Note: If chemical tanks and associated rail traffic is of interest to you then take a look at 'Lineside Industries - Dyes and Inks'. Chemical factories often produced a limited range of goods, dye factories made use of many. Petrochemicals and the modelling of oil refineries are discussed under 'Lineside Industries - Petroleum and LPG' and fertilisers are considered separately under 'Lineside Industries - Agricultural Merchants & Fertilisers.
Notes on some of the individual chemical company histories have been included at the end of this section.
The so called 'heavy chemical industries' produce all the commonly used industrial chemicals in bulk, including acids, alkalis, gasses, alcohols and some odds and ends. Their customers are other industries who use these chemicals for processing or as 'feed stock' to make more complex chemical products. This is a complex area, within the industry large quantities of one chemical are often used in the manufacture of another and some chemicals were produced as a byproduct of other processes. As a result you may find a large works producing a range of chemicals or smaller works producing a single, or very small range of chemical product(s).
The main reason for considering a chemicals plant on a layout is probably the use of PO stock. Following the Railways Rates Act of 1892 the railway companies were not obliged to provide rolling stock for materials which might damage them, hence there are a large number of PO designs and liveries associated with the chemical industry such as salt wagons, lime wagons and acid tanks. Which of these should appear depends on what the factory is producing.
To give yourself some leeway the best option has to be a generic 'chemical factory' with no specific products. If you want to include elements or rolling stock associated with a specific chemical industry these are discussed in more detail below.
There is at least one rather modern 'N' gauge generic 'chemical' factory, featuring large roof mounted tanks, available from one of the Continental firms (this is okay, but it makes a better paint factory or lubricating oil works).
Depending upon what was being made the slope-sided buildings associated with powdery or granular materials discussed in 'Lineside Industries - Prototype industrial ancillary structures' might appear.
Fig ___ Building for bulk powder or granular materials
Where the powder or granular material is to be loaded into or delivered by railway wagons it is common to have a covered conveyor belt extending from somewhere near the top of the building to a covered area for loading or unloading hopper wagons. These diagonal conveyors are a characteristic of the heavier side of the chemical industry and can be easily represented using strip wood with printed paper sides and top with any 3-D detail added using strips of card.
The plan shown below is very loosely based on the arrangement of the Albright and Wilson works at Whitehaven which produced phosphorus-based detergents by the "wet" process. The track plan allows for all likely forms of traffic to and from the works (coal for the boilers would use siding B). A run-round loop can be added, running from the branch into the works, back to the right round the corner and re-joining the main line (although this does use the main line for the run round). The prototype was on the end of a lengthy single track line which seems to have been laid in just to serve this works (there may have been other factories served by this branch however). There were no run-round facilities visible so going one way or the other the engine would have been pushing (I believe it was when leaving the works as all the sidings there seem to have been kick-backs).
Fig ___ Chemical works for a corner site
Many older chemical works could be simply represented with a couple of large buildings, resembling the mills of Lancashire, with a couple of chimneys and a few tanks gathered about them. The kits intended for oil refineries may be used to some effect to produce a larger installation.
Index for Specific Chemical Industries
The various chemicals covered in this section each support an independent industry, each having its own distinctive structures and in some cases railway rolling stock, having said which many chemical works produce a range of chemicals at a single combined works. Notable examples include the closely related alkali and chlorine industries, sulphuric and nitric acid were also often made at a single works. Sketches of some of the buildings and rolling stock associated with particular chemicals are included under their respective industries.
The chemical industry is not a recent development, the word chemistry comes from Alchemy, derived from the Arabic term 'The Art (or Science) of Khem', Khem being the Arabic word for Black and Egypt being known as the 'Black Land'. Prior to the nineteenth century most chemicals used were naturally occurring minerals and organic matter from living things. Chemistry was in its infancy but prompted by the Industrial Revolution it developed rapidly and spawned a major 'industry'.
Chemists understand the processes relating to the interaction of materials, they can set up equipment on a bench, run the process and produce small quantities of the desired product. If this is then scaled up for industrial purposes it is known as a 'batch process', and most early chemical production worked on the batch system. One example being the processing of gas works tar using large iron 'pot stills' to separate out the tar into its constituents.
Chemical engineers are a product of the industrial revolution, they work out how to take the basic process and convert or modify it so that, ideally, it runs continuously and produces many tons of the product per day. As a result chemical engineers are often given the title 'process engineer'. In the case of coal tar they developed the 'pipe still' (discussed under 'Lineside Industries - Chemical Industries - Coal Tar Distillers'), for making fertiliser from nitric acid they produced the 'acid tower', and there are many more examples. In Britain, with the legacy of the Norman Invasion and the 'us and them' culture it spawned, the pastimes of the wealthy (the 'Normans') were held in higher status than the practical products of 'industry' (the 'peasants'). Given some of the prices these days railway modelling should be a very high status hobby, but that's another story. The scientific community was rather 'sniffy' about chemical engineering, holding the chemists, physicists and mathematicians in higher regard than these 'mere' engineers (although completely dependent on their products). In the rest of the world, particularly France, Germany and the USA, the potential contribution of real-world chemical engineering was more fully appreciated, nevertheless it was in Manchester in 1901 that an engineer called George Davis published his very influential 'Handbook of Chemical Engineering'.
Chemicals are seldom used on their own, they are usually required for some other process. In Britain soap manufacture and textiles were two of the biggest customers for chemical works. Textile manufacture required large quantities of alkalis, acids, soaps (see Margarine & Soap), dyes and 'mordants' (see under Dyes & Inks). The demands of the textile industry therefore prompted and largely funded the early development of the chemical industry whilst the railways facilitated the delivery of raw materials and the transportation of finished chemicals. As other industries grew in importance the chemical industry developed to service their needs, for example factories were set up in the later 1930s to make TEL (tetra ethyl lead) for use as an anti-knock agent in petrol (see also Lineside Industries - Petroleum and LPG).
One of the most important sources of chemicals during the period under consideration has been the town gas works (discussed under Lineside Industries - Gas Works Coke and Smokeless Fuels) and the coke plants associated with steel works. The by-products from the coal tar included a range of chemicals including ammonia (used for, amongst other things, making nitrate fertilisers).
There is a Museum of the Chemical Industry (Gossage Building, Mersey Road, Widnes, WA8 0DF (Tel: 0151 240 1121) which is open every day except Mondays (or was when I visited it some years ago).
The history of the British chemical industry has been one of gradual consolidation and amalgamation. The most significant event occurred in 1926 when the British Dyestuffs Corporation merged with Nobel Industries, United Alkali Co and Brunner Mond & Co to form the giant Imperial Chemical Industries or ICI. Chemicals are a wide ranging field however and there remained a number of smaller firms, mostly producing a small range of specialist products, a couple of the larger examples are the BOC Group, which produces liquefied gasses, notably carbon dioxide, nitrogen and oxygen and Albright and Wilson who specialised in phosphorous based chemicals (they started out supplying white phosphorous to the match industry).
There are only a limited number of major sources for industrial chemicals; Vegetable matter supplies many chemicals we take for granted in everyday life, coal and wood provide carbon and some interesting oily liquids, various minerals such as saltpetre (imported in considerable quantities), limestone (calcium carbonate) and salt are used in a wide range of processes whilst petroleum oil has become increasingly important particularly since the 1940's.
The chemical industry considers itself divided into two branches, heavy and light. The heavy chemical industry deals with raw materials and primary processing, the quantities involved in the heavy chemical industry tend to favour wagon-load or even train-load consignments. The light side of the industry deals mainly with combining or refining the heavy chemicals to produce end-user material and this naturally tends to favour smaller consignments with wagon-load being common but train loads being rare.
Important chemicals can be divided into three main classes; 'organic', acids and alkalis (more correctly called 'bases').
Organic chemicals are those based on carbon, mainly the hydrocarbons found in oil, coal and wood, inorganic chemistry deals with materials not involving carbon most of which have little practical application. Most organic chemicals are derived from living or once living things and to date about three million organic chemicals have been identified.
In 1828 a German scientist (Woehler) found a way of synthesising organic Urea from inorganic ammonium cyanate, proving the substances which had been obtained from living organisms were no different than materials obtained from minerals. This was a major breakthrough and changed the face of industrial chemistry.
Pure carbon is itself an important chemical, charcoal, anthracite coal and coke are all fairly pure forms of carbon with many industrial uses. Lamp black is finely divided carbon (better known as 'soot') made by burning oil or coal gas with a restricted amount of air. Lampblack was used to make inks which did not fade and shoe polish but its most important use after the 1930's was in motor car tyres. Rubber tyres are actually about one third carbon, which makes the rubber much more hard wearing and accounts for the black colour. Lampblack was shipped in cloth bags but being a fine powder it leaked out and stained the surrounding area, railway wagons which had been used to carry the stuff needed extra sweeping out to prepare them for their next cargo. Coke, made from coal or obtained from oil, is pure carbon and as well as being a fuel it has a range of uses in industrial chemistry. Similarly charcoal (made from wood) is almost pure carbon and, up to the 1930s charcoal was an important industrial chemical (coconut charcoal is still a widely used material in the filters of gas masks). The by-products of coke and charcoal production also yielded a range of useful chemicals (see also under Lineside Industries - Chemical Industries - Coal Tar Distillers and Wood Tar Distillers).
In 1564 a deposit of graphite (a form of carbon) was found in the lake district that was so pure it could be sawn into sheets and it was used to make rather crude pencils. This stuff was so valuable it was escorted by armed guards when shipped to London. By the 1780's the Lakes graphite was exhausted so experiments started on alternatives, Staedler the German company took up a patent in 1785 which used graphite mixed with clay and baked to form a 'pencil lead', this is the type of pencil we still use today. Graphite was also imported from Ceylon, however it can be made in bulk by heating coke in an electric furnace. As well as pencil leads it is used as a lubricant, in the polish for black metals (stove polish) and for electrodes.
Acids and alkalis have a rather close relationship in chemistry, one of the oldest chemical tests is the 'Litmus paper', consisting of blotting paper soaked in vegetable dyes (there are actually a combination of 15 dyes in the paper). Acids turn blue litmus paper red, alkalies turn red litmus paper blue, the test is reliable and the phrase 'litmus test' passed into everyday language to indicate some definitive way of separating two classes.
Acids in their pure form may be solids (such as crystals of citric acid from fruit), liquids (such as sulphuric acid) or even a gas (hydrochloric acid). Bases are compounds which react with acids to produce water and a salt, bases which are soluble in water are called alkalis. Salts are acids in which the hydrogen has been replaced by a metal.
Up to (I believe) the early 1960s a lot of liquid acids were shipped in pottery vessels called 'acid jars', the example shown is typical, it stands nearly six feet high and holds 200 gallons of acid. One common application was the transport of hydrochloric acid (also known as muriatic acid).
Fig ___ An 'acid jar'
These jars would be seen at the works and were transported by rail in specially built wagons (see under hydrochloric acid below).
The mineral acids, sulphuric and nitric, were discovered by the Arabs in about 1000 AD. By far the most important is sulphuric acid which is used in a vast range of processes (including the manufacture of nitric acid) and is probably produced in greater quantities than any other chemical world wide. Consumption per head of sulphuric acid actually gives a fair indication of the industrial capacity of a country.
Sulphuric acid was originally produced by heating hydrated iron sulphate (known as 'green vitriol') and absorbing the gas produced in water (hence 'oil of vitriol', a once common term for sulphuric acid). This method was superseded by burning sulphur in the form of crude sulphur ('brimstone') and nitre (potassium nitrate or 'saltpetre') under a glass bell to make sulphur dioxide which again mixed with water to make the acid, but in 1746 John Roebuck of Birmingham devised the 'lead chamber process'.
This process burned the sulphur and nitre in a furnace, the fumes were then fed into a lead lined chamber with a few inches of sulphuric acid in the bottom (if you just use water you get a rather nasty 'mist' forming). The result is an ever more concentrated form of the acid, known as oleum, which is then diluted with water to produce industrial strength sulphuric acid. Early lead chambers were modest affairs, a typical works of the early nineteenth century might have six chambers each six foot wide, twelve feet long and about ten feet high with iron trays on which the sulphur and nitre mix was burned. The chambers would be enclosed in a building often of rather crude wooden construction.
Sulphuric acid or 'vitriol' has been commercially produced in Britain since the 1730's (in the area around Twickenham and Richmond, near London) and by the time the railways were being built the UK was exporting over two thousand tons a year. Oleum is the more concentrated form, sometimes called 'fuming sulphuric acid' (sulphuric acid was originally called 'oil of vitriol' and oleum is the Latin for 'oil').
Sulphuric acid (H2SO4) was in great demand in the expanding industrial economy for making bleach and explosives, allowing the manufacture of Soda instead of expensive potash for soap makers and glass works and freeing more of the available potassium salts to be used for agriculture.
In 1827 the Guy-Lussac Tower system was developed, which soon established itself as the most popular method for making the acid. The tower was usually about 50 feet high, and 8 feet across, lined with lead with a timber frame and timber cladding, set up beside a large, usually rectangular, lead chamber structure. There was also a second tower, called a Glover tower of similar construction and a tall chimney. The illustration is based on a model of one of the early examples, the tall tower remained a feature of several acid works into the 1950s (possibly later), they tended to be rectangular with a 'hut' type structure on the top. The multi-compartment rectangular 'lead chamber' bit was still being built in the 1950s.
Fig ___ An early sulphuric acid plant
The size increased steadily until by the 1930's chambers of nearly 30,000 cubic feet (850,000 litres) were in operation. The chamber may be a large, boxlike room or an enclosure in the form of a truncated cone. There may be from three to twelve chambers in a series; the gases pass through each in succession, and the acid produced contains about 65 percent sulphuric acid. The base of the chambers inside tower is always supported above the ground so that any leaks will be spotted quickly.
By the 1870's the manufacture of sulphuric acid was well organised and quite efficient whilst cheap saltpetre imported from Chile had brought the cost down. Principal producing areas were London, Lancashire, the North East and Glasgow, although odd plants were in use in or near many cities. In about 1918 an alternative process was developed in which Iron Pyrites (FeS2, a kind of rock sometimes called 'fools gold') was heated to drive off the sulphur, this was a lot cheaper than the saltpetre. Pyrites had been known about for many years, when struck against iron or flint they produce sparks, so they were used in early 'wheellock' muskets and pistols. By the 1930s the bulk of the sulphur used for acid production in the UK came from pyrites which we imported from Spain in large quantities. This material is a light grey rock rather similar to limestone in appearance although more grey than white. An alternative source of sulphur, widely used to make sulphuric acid, was the 'spent oxide' from gasworks (see also Lineside Industries - Gas Works, Coke and Smokeless Fuels).
Phil Clarke sent me some scanned 'post card' pictures of the vitriol works at Glasgow in the 1920s, asking what they depicted. The illustrations below are based on Mr Clarke's pictures which I have tinted to try and highlight the detail (the colours are not prototypical, the whole lot would probably be shades of dark grey). I believe the three main elements are as indicated. I believe the piles of material in the foreground are the imported pyrites.
Fig ___ A 1920s sulphuric acid plant
Do not be put off by the complexity of the tapering towers, there were simple square ones as well as shown below.
You may also see mention of Copperas Works on old maps, copperas (sometimes called green vitriol) is ferrous sulphate (a compound of iron and sulphur) and can be used to make sulphuric acid by distillation. Copperas occurs naturally and deposits are often associated with coal mining. However the Copperas works had generally disappeared in the second half of the nineteenth century.
After the 1880s sulphur was also recovered in a very pure state from the 'alkali waste' of the Leblanc process (discussed below), but this 'recovered sulphur' was too expensive to be burned for making acid. The technology was developed at the Chance Bros establishment in Oldbury near Birmingham (they became Chance & Hunt Limited in the late 1890s and part of ICI in 1926, in April 1999 Chance & Hunt once again became Chance & Hunt Limited, following a management buy-out from ICI and in July 2002 joined the pan-European Azelis group of companies.)
In all the above processes the resulting sulphur trioxide (SO3) combines with the water (H2O) to produce the acid (H2SO4). The process released a lot of noxious gasses up the chimneys until the 1860's when legislation was introduced requiring de-nitrifying towers to wash the nitre from the fumes, this could then be recovered and re-used. These were simply a tall structure, as high as a five storey building, and 10-20 feet (3-7m) square at the base with a water feed pipe running up the side, a large pipe entering at the base and another emerging from the top and returning down to ground level (thence to the base of the chimney).
1831 Peregrine Phillips developed the contact process for the production of sulphuric acid, it was first used on an industrial scale 1875 but there were several problems to solve and the process was not much used in Britain until about the time of the First World War. The contact process is much cheaper to run than the old lead chamber system and by the 1920s it was established as the standard method of production (and continues as such today). The old wooden sulphuric acid towers with their valuable lead lining did not remain standing long after they ceased production and had probably all disappeared by about 1940. The sketch below shows a rather neat (and easy to model) example, this would replace the three tapering towers in the works shown above.
Rectangular Sulphuric Acid Tower (sketched from a photo from about 1930)
The contact process has three stages, first sulphur is burned to produce sulphur dioxide, a catalyst is then used to further oxidise this into sulphur trioxide, the trioxide is then disollved in concentrated sulphuric acid to produce highly concentrated oleum (which is then diluted to the required strength). You cannot make the acid by dissolving the trioxide in water as so much heat is generated it produces a vapour.
The illustration below is based on a model (held by the Science Museum in London) of a sulphuric acid plant built in the early 1950s. To my untutored eye this plant appears to be of the 'lead chamber' type (the assumed chamber is to the left), but this seems unlikely at this date and it is presumably a contact process plant. I have made some slight changes to the original for modelling purposes, for example the row of small tanks (bottom centre) are shown as 'Ratio' type horizontal tanks, on the prototype these were two rows of vertical tanks to either side of the walkway.
Fig ___ An 1950s sulphuric acid plant
Modern sulphuric acid plants can be quite small establishments and feature several small storage tanks similar to those in the Ratio Oil Tank kit, often silver in colour, and a silver tower with complex large diameter external silver pipework roughly two and a half stories high. These towers are similar to the 'oil refinery' kits available from continental manufacturers, although these are rather thin and would benefit from some additional external pipework for this application. You could make your own a using a 'Vicks' inhaler tube with wire pipe-work.
The example shown below is typical I believe, although the key characteristic feature is the tower and large diameter pipework shown at A on the right of the picture.
Fig ___ A modern sulphuric acid plant
Sulphuric acid can be shipped in glass containers, bottles and carboys, and also in iron tanks, the acid 'passivates' the iron on contact so corrosion does not occur. These tanks could be removable tanks, commonly called 'de-mountable' tanks, and an example of a de-mountable tank for sulphuric acid, a so called 'Vitriol' tank, is available as a kit from Fleetline.
Sulphuric Acid Tank wagon
Carboys are spherical glass bottles about eighteen inches in diameter carried in conical wicker baskets packed with straw (see Appendix One - Packaging materials and containers for more on carboys).
Alum (aluminium ammonium sulphate) is a 'mordant', a vital constituent of dyes, and was in great demand for the growing textile industry. Supplies were obtained from mines such as those at Pleasington in Lancashire as early as the seventeenth century. The alum is often found in shale deposits associated with coal mines and a process to recover small amounts of alum from the shale using sulphuric acid was invented in 1850, adding to the demands on the acid manufactures. An alum factory might be quite small, traffic inwards would be shale from a local coal mine and sulphuric acid in glass carboys or iron tanks, outgoing would be sacks of alum.
Sulphuric acid is such an important chemical there are inevitably concerns regarding supplies of raw materials, with the main problem being pure sulphur. Sulphur is a brittle, pale-yellow, nonmetallic element which has been used since ancient times. Most of the sulphur used comes from deposits in Texas and Chile and although large these are limited. Imported sulphur was shipped in bags and barrels but more often in bulk, the latter being transported in sheeted hopper wagons by the later 1960s.
After the Second World War ICI developed a process for recovering sulphur from a rock called Anhydrite and began commercial mining at Billingham. Anhydrite or calcium sulphate (CaSO4), resembles marble in appearance, it is a hard granular material chemically similar to Gypsum. British rail built special hopper wagons to carry the white granular powder from Billingham to the ICI sulphuric acid plant at Widnes. Sulphur can be recovered from some petroleum oils and by the 1960's something like ten percent of the world supply of sulphur came from oil refineries.
Sulphur is also used to make Calcium Bisulphate (used in paper making to dissolve the unwanted lignin in wood pulp and leave the cellulose fibres), for vulcanising rubber, making matches (the head is actually phosphorous sulphide), as an insecticide and fungicide and in various medicines.
The chemistry involved in making nitric acid is straightforward, but the engineering to do this on an industrial scale is very complex. Nitric acid (HNO3) is difficult stuff to handle as it eats most metals, one of its common names is 'engravers acid' (although it is fairly easy going on cast iron). It is shipped in glass bottles, glass carboys, large non porous earthenware jars or these days in specially lined railway tank wagons.
Nitric acid used to be made by distilling saltpetre imported from Chile with concentrated sulphuric acid in horizontal cast iron stills, condensing the resulting vapour in stoneware jars called Woulfe's bottles. Someone then came up with vertical earthenware condensers, air was blown up these, condensing the acid vapour (which ran out at the bottom) the remainder being passed to a tall tower where a waterfall dissolved the peroxides and other nasties remaining in the gas.
The big change came when someone worked out how to make the stuff from ammonia (NH3), all you do is mix the ammonia with air and heat it in the presence of a platinum catalyst, producing nitrogen monoxide and steam, this is passed through water to produce the nitric acid. Having said which it took nearly a hundred years to work out the details of this process and it was not used industrially until about the time of the First World War, shortly after the method for making synthetic ammonia was developed (discussed below). The early nitric acid plants were made of stoneware so had to operate at atmospheric pressure, but the development of stainless steels in the mid-1920s enabled pressure operation to be developed. By the early 1930s the heat generated in the process was being used to generate steam to produce power to run the plant, by the 1940s the plants were energy self-sufficient. By the 1960s nitric acid plants were producing 200 tons per day, by the mid 1970s the figure was about 350 tons per day.
A key feature of a modern (post 1930s) nitric acid plant is the tall silvery tower at its centre, the sketch below is based on a model of a plant built in about 2000, the model was open frame, I have added walls, you can add windows and doors to taste. See also Farming Related Industries - Fertilisers for a picture of a plant in Scotland.
Nitric Acid Plant
Nitric acid is a colorless liquid however pure acid decomposes at high temperatures or on exposure to strong light and becomes yellow. This stuff has many uses, for parting gold and silver, in the manufacture of coal-tar dyes and as various metallic nitrates. Most is these days used to make fertilisers, either for ammonium nitrate or in the various nitrophosphate processes. Ammonium nitrate is also used in the manufacture of explosives and at one time nitrate fertiliser (mixed with coal dust and fuel oil) was used by farmers to blow up tree stumps and by terrorists to make bombs but these days it has a small percentage of ammonium sulphate added which renders the nitrate non-explosive.
Up to the 1950's lead nitrate (made by treating lead with nitric acid) was an important 'mordant' in the textile industry and more recently nitric acid has been a regular rail cargo transported in purpose built rail tanks to nuclear reprocessing establishments.
Fuming nitric acid consists of a solution of nitrogen peroxide in concentrated nitric acid, it is a deep red in colour and was prepared by distilling dry sodium nitrate with concentrated sulphuric acid.
Hydrochloric acid (also known as muriatic acid) was originally manufactured using salt and sulphuric acid (muriatic means 'pertaining to brine or salt'). It is the third of the 'mineral acids' and is actually hydrogen chloride gas (HCl) dissolved in water. Following the Alkali Act 1863 the hydrogen chloride gas produced in the Leblanc soda works had to be recovered (dissolved in water) and the soda manufacturers found it to be a valuable by-product (discussed below under Alkalis). It eats most metals so was transported in earthenware jars (as illustrated above), although dangerous it is actually one of the main constituents of stomach acid in humans.
The sketch below is a 15 ton 9-plank wagon built to carry non-porous earthenware jars of hydrochloric acid, this example was sketched from a photo dated about 1910 I believe and the acid was probably recovered from the washing towers at an alkali works (discussed below). This is not difficult to model, replace the sides on a Peco 7 plank wagon with plain scribed card, add the strapping for 10x20 thou strip and internal dividers from 20 thou card. Make the tops of the jars from beads with the top of a dress making pin inserted in the hole, bed these into Milliput inside the frame. The jars should have lifting lugs but these are below the top of the wagon and (in N) you can get away with this.
Fig ___ An 'acid jar' wagon
Hydrochloric acid was once used for making chlorine by adding it to manganese dioxide (in the form of managese ore or recovered from other processes), these days the situation is reversed, hydrochloric acid is made by mixing sulphuric acid with sodium chloride, itself derived from sodium chlorate (common table salt), the resulting gas dissolves in water to produce the acid.
Both hydrochloric acid and a solid called 'salt cake' (sodium sulphate with impurities) are produced from salt in a device called a Mannheim Furnace, which is a brick lined chamber about ten to fifteen foot in diameter with an iron pan built into the bottom. The furnace is fed through the top and produces hydrochloric acid gas which is piped off and the salt cake which is periodically removed through a door in the side.
Hydrochloric acid oxidised with manganese dioxide produces chlorine, which when mixed with lime produced the 'bleaching powder' (discussed separately below) used in the paper and cloth industries. It is also used in making photographic materials, drugs and dyes. It is used to make glucose from starch and glue from animal bones and it is important for the plastics industry (notably in the manufacture of PVC). It eats metal but can be shipped in rubber lined metal tanks and drums or in glass bottles and carboys. One of the main uses for hydrochloric acid is to prepare metals for galvanising (coating with zinc) or electro-plating (it removes rust from iron and steel for example, the practice is called 'pickling'). Once used for this purpose it was often sold on but the impurities it collected were often undesirable and these days the steel works tend to employ hydrochloric acid regeneration processes. All of these seem to employ heating of the liquor but by recuperation of the spent acid a closed acid loop is established and the steel works needs less frequent supplies. The iron oxide by-product of the regeneration process is also valuable and is used in a variety of secondary industries.
Salt cake is chemically sodium sulphate (Na2SO4) forms white crystals or powder, it is used in soap manufacture, paper pulping (especially for kraft paper, see Paper & Paper Products), as a filler in synthetic detergents and in processing textile fibres. It has several uses in the manufacture of ceramics and is important for the manufacture of plate glass but since the 1960's it has increasingly been recovered from natural sources. It is shipped either in bags or in metal drums.
Acetic acid is what gives vinegar its taste but it is also an important industrial chemical, in its pure form it is called Glacial acetic acid. Up to the 1940s a lot of industrial grade acetic acid was recovered from wood distillation plants in the forested areas of the country (these are discussed separately under Wood Tar Distillers). From the 1930s it was increasingly produced in oil refineries by reacting methanol with carbon monoxide in the presence of a catalyst. Acetic acid is used in a range of processes including plastics manufacture, dyes, pesticides, and as a coagulant for latex in rubber manufacture and has been shipped in bulk rail tankers since the late 1960's. It is a clear colourless liquid which does not leave a coloured stain, it is flammable (it ignites at about 800 degrees Celsius) and when shipped it is usually marked as being corrosive Vinegar is acetic acid diluted with water, typically there will be between 4 and 8 percent acetic acid in the mix along with traces of a range of other chemicals. Vinegar brewing is considered separately in the section on food related industries. Most vinegar is made by fermenting fruit juice or 'malt' (see under Beer, Ales & Cider) with a mold, the liquid can then be distilled to produce a clear colourless liquid called 'white vinegar'. Vinegar is not pure acetic acid and is not used for industrial processes.
Phosphoric acid is another important industrial chemical, it was discovered in the 1850's and has been produced in considerable quantity (it is usually made by combining phosphorous pentoxide with water but usually shipped as a liquid with no water in it called orthophosphoric acid). Phosphoric acid is an important fertiliser (see also 'Lineside Industries - Agricultural Merchants and Fertilisers') and is used in a range of processes including dyeing cotton, sugar refining, soap manufacture, metal pickling & rust proofing, dyes and petrol additives and even as a food additive (notably in 'fizzy' drinks). It is often shipped as a clear liquid in specially lined tank wagons and drums (it attacks iron based metals and eats through glass) but in its pure form it is a solid transparent crystalline material originally shipped in jute bags but these days in lined steel drums. Peco offer an N Gauge tank wagon in Albright & Wilson livery lettered for carrying phosphoric acid and Hornby offer a depressed centre four wheeler tank in similar livery for OO (see below under Chemical Manufacturers - Albright and Wilson). Note that phosphoric acid tanks are usually heavily stained with white in service.
Phosphoric acid plants feature a lot of pipework and numbers of horizontal tanks (of the type offered by Ratio as oil tanks) and some larger but not very tall tanks (short versions of the type found in oil refineries), at the core is a tower of some kind with a central tubular structure. The tower is usually the tallest structure, the example below is typical but it is the shortest example I could find.
Fig ___ Tower at the centre of a phosphoric acid plant
For the larger tanks a commercial oil tank can be cut in half to produce one covered and one open tank (you need to add the walkway across the top of the tank).
Hydrofluoric acid (HF) is a solution of hydrogen fluoride in water, notable as it eats through glass (it attacks the silicon dioxide that is a major component of most forms of glass). Although it is not regarded as a strong acid it is extremely corrosive, rather toxic and hence difficult to handle. This acid is made using fluorspar (calcium fluoride, also known as Blue John) which is treated with concentrated sulphuric acid to yield hydrofluoric acid. The fluorspar used to be mined at Castleton in Derbyshire, but that mine now only produces it for ornamental ware and fluorspar is now imported.
Hydrofluoric acid is used by oil refineries for some processes but its main use is probably the manufacture of materials such as PTFE (polytetrafluoroethylene or Teflon) and refrigerants such as freon and arcton. It is transported in small quantities in specially lined or polythene containers (I think it was transported in earthenware bottles but I am not certain on that point).
Hydrocyanic Acid (HCN) is almost certainly the most dangerous cargo carried by rail, technically the correct name should be Hydrogen Cyanide (it is a gas at slightly above room temperature). Other names used for this stuff are prussic acid, formonitrile, aero liquid HCN, and zaclondiscoids. It was first derived from Prussian Blue pigment (hence Prussic acid) and in the 1780s it was called 'Blue acid' by a Swedish chemist, this lead to the names for the range of cyanide compounds, which are named from the Greek word for 'blue'. There was initially a limited demand for this stuff, it was used to make potassium cyanide and sodium cyanide for the gold mines (and for entomologists who used it to kill specimens), for some types of rat poisons and is some methods of fumigation. In the early 1890s a Mr G.T. Beilby patented a method of production using ammonia gas passed over glowing coal. This method was used until Hamilton Castner in 1894 developed a synthesis starting from coal, ammonia, and sodium yielding sodium cyanide, which reacts with acid to form gaseous HCN. Between the two world wars the German chemical company IG Farben developed a process using methane and ammonia which remains the main method of production today (although there are others, and it is produces as a byproduct of some other work notably the manufacture of acrylonitrile).
More recently the uses of hydrogen cyanide have expanded a lot, it is used in producing adiponitrile for nylon, methyl methacrylate, sodium cyanide, cyanuric chloride, chelating agents, and miscellaneous other uses, including in the manufacture of insecticides and rodenticides for fumigating enclosed spaces, ferrocyanides, acrylates, lactic acid, pharmaceuticals, and specialty chemicals. It is a severe explosion hazard when exposed to heat or flame, or by chemical reaction with oxidizers. Under certain conditions, particularly contact with alkaline materials, hydrogen cyanides can polymerize or decompose explosively. The gas forms explosive mixtures with air and will react with water, steam, acid, or acid fumes to produce highly toxic fumes of cyanides. This stuff is very toxic by inhalation, ingestion and through skin contact. Inhalation, ingestion or skin contact may be fatal (it can be absorbed through the skin). The TUA air braked four wheeled tank wagons built to transport HCN in the 1970s, owned by ICI (Grangemouth) they resemble the Peco long wheelbase tank but have raised ends to prevent the tank sliding off in a derailment. These operated under very strict rules, more fully discussed in the section on Freight Operations under 'Explosives, corrosives and compressed gasses'.
Alkalis may also be supplied as either solids or liquids, you may remember the school Chemistry mantra 'an acid plus a base produces a salt plus water', well alkalies supply the majority of the industrial 'bases' and there is an entire branch of chemical engineering known as the 'alkali industry' (up to the 1970s the UK was the worlds most important producer of alkali). This industry combines a range of chemical compounds, many of them based on chlorine and (since the mid 20th Century) generally produced in parallel in single large and generally efficient plants.
The word alkali is another inheritance from Arabic chemists and the term 'alkaline' was widely used to indicate a 'base' (although modern chemists define the term rather more rigorously). In industry it is usually a form of salt that is referred to, of which common examples include calcium carbonate (sometimes called 'lime' or 'free lime'), sodium hydroxide (often called caustic soda, made from salt) and potassium hydroxide (commonly called 'caustic potash). Lye is a generic term for both potassium and sodium hydroxide or even a mixture of the two.
The most important alkali has always been Sodium Carbonate, commonly called Soda. Much used in a range of industrial processes relating to everything from glass to soap the original source was burnt seaweed. From the early nineteenth century to around the time of the First World War soda was made by the (French) Le Blanc process (Le Blanc himself received no remuneration as the revolutionary French government confiscated the valuable patent rights). In Le Blanc's process salt is treated with pure sulphuric acid to produce sodium sulphate, this is then burned in a soda furnace with lime and coal to produce crude soda commonly called 'soda ash'. British production started in Liverpool in the early 1820's and plants were established at St Helens soon after.
Fig ___ Typical LeBlanc works
This image is in the public domain
The main drawback with Leblanc's process was that it produced fumes which turned into clouds of hydrochloric acid when they mixed with water in the air. There were also other hazardous by-products including nitrogen oxides, sulphur and chlorine gas, which often escaped or were released to the atmosphere. Obviously this polution annoyed the neighbours and was a problem which caused considerable litigation. Some soda factories had chimneys up to 300 foot high to try and reduce the local damage (that is about two feet or 60cm high in N gauge). A businessman and engineer called Gossage had interests in the chemical and soap industries and in 1836 he devised a washing tower to remove the dangerous fumes. He used a nearby disused windmill, filled with brushwood, with water sprayed in at the top and the smoke fed in at the bottom, the water dissolved most of the acid although at the time he allowed this to run off into a nearby river. A law was passed to encourage factories to reduce their pollution (the 1863 Alkali Act) and required these towers to be used. Similar cleaning systems are in use today, usually referred to as 'scrubbers'.
Washing towers were built of brick and/or wood, typically about as tall as a five or six storey building and about 20-30 feet (7-10m) square at the base.
It wasn't long before someone spotted that the resulting hydrochloric acid was a useful industrial chemical and the acid from these towers was recovered and decanted into large earthenware jars (see picture under acids above). Other materials produce at a larger Leblanc soda works might include; chlorine (which could be used on site to manufacture bleaching powder (discussed in detail below) and other chlorates). Ordinary alkali can be made from the sulphate of soda, also produced were caustic soda, soda crystals, bicarbonate of soda, calcium chloride, sodium silicate and ammonium chloride. It was common practice to recover sulphur from the alkali waste.
At about the turn of the century the British chemists John Brunner and Ludwig Mond took up the alternative ammonia-soda 'Solvay' Soda process and founded Brunner Mond to exploit it. This process had been invented in 1811 by a Mr Freznel but was not developed industrially until 1861 by Ernest Solvay (1838-1922), by whose name it became known. The Solvay process featured an 80 foot tall 'carbonating tower', in which ammoniated brine was poured down from the top while carbon dioxide bubbled up from the bottom, producing the desired sodium carbonate. The new process operated continuously, was comparatively free of hazardous by-products and with an easily purified final product. It is much less polluting than the Le Blanc system and a by-product is moderately valuable calcium chloride, but it was only in the later 1920s that this process completely replaced the Le Blanc based production and the old buildings remained in place for many years after that.
The drawbacks of the Solvay system are the amount of energy required (there is a lot of heating and drying in the process) and the chloride effluent that can contaminates streams and rivers if not recovered properly at the plant. Today the high energy cost and more stringent pollution controls have told against the Solvay process and there has been increasing use of naturally occurring deposits of soda, mainly from America.
A Solvay process plant would require supplies of uses salt, ammonia and limestone.
Crude soda ash is a greyish white powder and has many uses in industry. The railways have supplied rolling stock reserved for this traffic since at least the 1920's, BR reserved some of their COVHOP wagons and their metal bodied open sand wagons fitted with a sheet supporter specifically for this traffic. The railways were still shifting it in bulk in the later 1980s (quite possibly later than that).
Fig ___ BR soda ash wagon
One of its uses is in petrol refining and hoppers of sheeted opens of soda ash would be regular visitors to a refinery.
To obtain pure soda the ash was immersed in iron tanks full of water for several hours and the resulting liquor was then evaporated in heated lead pans. Soda is an important chemical in textile production and is used in glass and paper making, aluminium production and in soaps.
The dissolved soda is allowed to cool slowly it forms crystals which were sold as 'washing soda' (actually there were other processes here to remove trace impurities but non required disctinctive structures).
Caustic Soda (sodium hydroxide, sometimes called Lye) was produced by converting soda ash (as a by-product of the Leblanc soda process) by adding calcium hydroxide (milk of lime) to the solution. In the late 19th century they began using electricity to break down salt water to produce chlorine at one electrode and caustic soda at the other and this became increasingly the norm as the old Leblanc works closed down. By the later 1930s I believe electrolysis of brine was the most common method of production.
One characteristic feature of caustic soda production is the large settling tank, a modern example is shown below, note the tank (on the right) is raised above the ground. As I understand it the apparatus mounted above the tank is a stiring device, with a central shaft passing down into the tank. The smaller tanks to the left are the follow-on stage where the liquor is heated and further processed.
Fig ___ Caustic Soda Settling Tank
The resulting caustic soda was run directly into the sheet-iron drums in which it was sold. These were sealed as soon as they got cold to prevent the absorption of moisture by the caustic (these days it goes into holding tanks).
Caustic soda was and is commonly supplied mixed with water and delivered in tank wagons to larger users, I believe some of these tank wagons may have been of the 'hutched' type illustrated under Chlorine below. It is also supplied as white pellets in sealed 10 lb cans.
Caustic soda is used in a very wide range of processes, including the manufacture of soap, for removing the hair from hides in the leather trade, in paper manufacture it is used to break down wood pulp, oil refineries use it in large quantities as a neutralising agent, it is used to commercially peel fruits and it is the basis of the plastics Rayon and cellophane. Cotton drawn through this stuff under tension comes out stronger and better able to take a dye, this is known as 'mercerisation' and the textile industry also uses caustic soda as a bleaching agent.
Chlorine, named for its green colour by Sir Humphrey Davey in 1810, it was first liquefied in 1822 by Michael Faraday, by 1900 it was available as a compressed gas in cylinders and I think it was sometimes shipped out pressurised to a liquid in unusual 'hutched tank wagons'. These were conventional cylindrical gas tanks mounted inside a wooden wagon body with a peaked roof top similar to the salt and lime wagons. There was a small ventilated box on the top to give access to the loading hatch on top of the tank. I understand that chlorine dissolved in water (called Hypochlorous acid) may also have been shipped in rail tanks, this was used as a bleach, an oxidizer, a deodorant, and a disinfectant.
Both ICI (Runcorn) and Castner Kellner Alkali (Runcorn) operated hutched tanks for the carriage of liquid chlorine in the 1930's but I am unsure when these tanks were phased out (or what the supposed function of the external wooden body was) but I believe some were built with a ten foot wheelbase (rather than nine foot), suggesting they were in use in the 1950's. Modelling this wagon is discussed fully in the section on Kit Bashing.
Fig___ Model and sketch of a hutched tank wagon
As the contents was compressed gas I suspect these wagons may have been painted light stone with a red band all the way round the body as 'class A' tanks but the only data I have does not mention this. The only details of the livery of which I am sure is that they carried fast traffic stars and were clearly marked Liquid Chlorine on the side.
The ICI 10'6" wheelbase chlorine tanks shown below in post war liveries were unfitted but had a long working life, they were introduced in the 1940s and were finally withdrawn in about 1980. By about 1960 the standard marking for compressed gasses was a vertical red band at each end of the white tank body and in about 1970 this changed to a white tank with horizontal orange band.
Fig ___ Chlorine tank wagons
In the mid 1950s there were a number of small bogie tankers built for Murgatroyds to carry liquid chlorine and there have been a number of pressurised four wheelers built for this traffic in the BR era. Murgattroyds had been in the salt business since the 1890s but the Murgatroyd Salt and Chemical works at Sandbach began operations in 1950, primarily to supply the Stavely Iron and Chemical Co.
Chlorine gas was originally made from hydrochloric acid (mostly supplied by the Leblanc alkali works as disciussed above) and manganese dioxide (in the form of managese ore or recovered from other processes), as most of the chemistry involved would eat metals the plant was made of earthenware. Next came the Weldon process, employing a complex series of chemical reactions and featuring a tall iron cylinder, say 9 feet (3m) wide and 30 feet (10m) high, called the oxidizer. This recycled the manganese but required regular shipments of ground chalk or limestone as well as lime. By the later 19th century however the Deacon process was used, in which hydrogen chloride gas (supplied as hydrochloric acid in earthenware jars) was reacted with atmospheric oxygen in a tall tower, producing water and chlorine gas. From the later 19th century they started using electricity to break down brine (producing chlorine gas at one electrode and caustic soda at the other. By the mid 20th century the electrolysis of brine was the normal method of manufacture.
Chlorine gas has a number of industrial uses, it was used as a bleach for cloth in the late 18th century. A chlorine solution in lime-water (hypochlorite) was first used as a germicide in the maternity wards of Vienna General Hospital in Austria in 1847, in the 1850s John Snow used it to disinfect the water supply in London after an outbreak of cholera. 'Chlorine bleaches' such as Domestos are actually based on a salt called sodium hypochlorite (which can be made using Hypochlorous acid mixed with a 'base'). Chlorine was used to make 'bleaching powder' (discussed below) and is also used for bleaching wood pulp in paper manufacture. Polyvinylchloride (PVC) was invented in 1912, at the time no one had any use for it.
Chlorine was also used to extract bromine from sea water, although you only get a couple of ounces of bromine from a ton or so of water this was worth having as it formed a vital part of the old lead-based anti-knock agent in petrol. At one time there were large factories engaged in this work, mainly in America but in the UK a plant was set up at Hayle in Cornwall which came on stream in 1940 and in the early 1950s a new plant was built at Amlwch on Anglsey (these plants are discussed in the section on Petrol Additives and Refinery Chemicals).
In the late 1700's Charles Tennant, a weaver by trade, invented bleaching powder by passing chlorine gas over slaked lime. This seemingly insignificant discovery revolutionised the linen trade by substantially reducing the time, effort and cost involved in the bleaching of cloth prior to dyeing. As a result a huge chemical business was built up, centred on St Rollux, a suburb of Glasgow. Bleaching powder was valuable stuff, commercial production began as the textile industry developed in the 1790's and it sold for over a hundred and forty pounds a ton. The cloth was dipped in a solution of the powder then in a bath of mild acid which released the chlorine itself, the bleached cloth was then dipped in a solution of 'antichlor' and then washed with water. The white powder was shipped in wooden barrels, themselves bleached to a light colour, with rust coloured metal hoops.
An early bleach works would typically employ a Weldon still (with its tall metal tower, see under Chlorine above) to produce chlorine gas, by the 1930s I believe they had the gas delivered (in the hutched tank wagons discussed above). There might be a lime kiln on site or lime might be brought in read-made (the lime used was slaked but not wet, so hutched wagons would be used). The lime is spread a few inches deep on trays in lead lined chambers, The chlorine gas admitted to the chamber, where it is absorbed by the lime (it has to be left for about 12 hours for all the chlorine to be absorbed). The powder is then turned over in the trays and the gas treatment repeated, on occasion a third treatment is required to produce the required strength of product.
Not all chlorine is the same, that produced by the Deacon process (a complicated system employing a catalyst) was weak and had to be further dried before it could be used to make bleaching powder. This was done in a tall, usually rectangular, brick tower filled with coke and supplied with a stream of moderately concentrated sulphuric acid. Normal bleaching chambers were impractical with Deacon process gas and very large stone build chambers were built, these were expensive and hard to keep gas tight and by about 1900 were replaced by a different system. This had a series of four horizontal iron tubes, mounted one above the other and each containing an archemedian screw. The powder was fed in at the top, the gas (mixed with air) at the bottom, the gas was forced up through the stack whilst the powder was carried along each pipe in turn by the screw and dropped down to the next level at the end. If the system was working properly the bleaching powder was delivered as a steady stream at the bottom whilst the gas escaping at the top had all chlorine removed and was pure air.
The finished product, a white powdery substance, was usually sold in tierces, that is, casks (barrels) containing 42 gallons (a third of a 'pipe') about four feet high and lined with brown paper. Filling the barrels had to be one of the worst jobs in history, it helped if the casks were on the ground floor and the packers worked through traps in the floor above. The casks had to be kept dry, and preferably cool, and were never exposed to direct sunlight (which could decompose the material and cause an explosion). It was shipped to paper makers and cotton bleachers with smaller quantities supplied to make disinfectants and the like.
Most bleach works appear to have featured a number of long low buildings arranged around a yard and a tall chimney. Remember the barrels would not be stacked in the open but would be protected from direct sunlight by a canopy on the loading bay. The example shown below is based on the popular Ashburton track plan, this industry gives the place a less rural feel than the traditional mill. Although the 'kick back' siding feeding the 'works' in notoriously troublesome to shunt it is long enough to accommodate the kind of building associated with a bleach works (for an alternative track plan based on the same station see 'Food Related Industries - Milk, Creameries and Dairies'). The sketch includes the tower used in the Weldon still and having the coopers workshops at the front allows for some interesting detailing work.
Fig ___ Track plan including a bleach works
A more concentrated form of bleaching powder, based on calcium hypochlorite, has since been developed. Based on different production processes, bleaching powder concentrate also contains calcium chloride or sodium chloride and calcium hydroxide. The effective chlorine content is more than 60 percent, by contrast, the effective chlorine content in conventional bleaching powder is around 30 percent.
One of the more important organic chemicals is acetylene gas, which is produced by adding calcium carbide to water. This gas burns well and was widely used for portable lighting such as bicycle lamps as well as for welding and cutting using cylinder-fed oxy-acetylene torches (invented in 1900 by Edmund Fouche - see also Lineside Industries - Industrial and agricultural vehicles and equipment).
The development of electric furnaces in the 1870's enabled the production of calcium carbide by heating a mixture of limestone and coke to a very high temperature. This cheap carbide reduced the cost of acetylene dramatically, but shipping carbide is somewhat problematic as it will react with water in the air to give off the acetylene. The carbide is a dark grey to black solid and has to be kept in sealed containers to keep out of contact with moisture from the air. It is therefore shipped in drums filled with a light oil or cased glass bottles.
Acetylene gas is itself unstable, if compressed into a cylinder it is likely to spontaneously explode. To get round this problem the acetylene cylinder is filled with a porous material soaked in acetone. The pressurised acetylene dissolves in the acetone and when the cylinder is opened and the pressure drops it bubbles out in the same way carbon dioxide comes out of a 'fizzy' drink when the bottle is opened. Dissolved in the acetone the acetylene is stable and it was removed from the list of official explosives in about 1905, so the cylinders could thereafter be shipped in ordinary railway wagons and vans.
Acetylene is most commonly associated with oxy-acetylene cutting torches but it also forms the basis of a wide range processes and chemicals. One of the more important is 'vinyl chloride' (tetrachloroetane), which is made using acetylene and hydrochloric acid. Vinyl chloride is used to make PVC and forms the basis of a great many widely used plastics (most of the hard plastics used in motor car interiors are based on vinyl chloride).
Ammonia is probably the most important inorganic chemical, it is a gas and by volume the third most important chemical produced today. Ammonia is unpleasant stuff, it combines with water to form corrosive ammonium hydroxide, as there is a lot of water on human skin this makes it dangerous. It is usually shipped as 'anhydrous ammonia' (NH3) refrigerated to -33 degrees centigrade and/or compressed at 125 psi into liquid form.
Ammonia was first recovered from coal gas in about 1850 but at about the time of the first World War the German Fritz Haber (1868-1934) invented a process for synthesizing ammonia using the nitrogen in the air. In the Haber process nitrogen and hydrogen are passed over a catalyst of iron and molybdenum at high temperatures. This was a strategically important development at the time as the ammonia was required for making nitrate type explosives.
Since the 1960s ammonia (NH3) has been mainly obtained from oil refineries from partial combustion of natural gas (mainly methane, CH4). Ammonia was usually shipped dissolved in water (Ammonium Hydroxide) in drums or tank wagons. Since the 1960's pure ammonia gas has been shipped in pressurised tank wagons. These are painted white with an orange band round them and with AMMONIA written on the side in lettering about eight inches to a foot high.
Fig ___ 90 ton ammonia tank wagon
Ammonia is an important fertiliser, either on its own or more commonly in the form of compounds such as ammonium nitrate, it is also used for making both nitric acid and Soda (sodium carbonate) and it has become increasingly important in the manufacture of plastics. Ammonia is used as a 'feed stock' in petro-chemicals, in its pure form it is also used in some types of refrigerator. The salts of ammonia are important for making fertilisers, drugs, dyes and explosives.
Oxygen, Nitrogen and Argon
These three gasses are generally recovered from the atmosphere, which is mostly nitrogen and about 21 percent oxygen. The sketch below shows a farily modern plant (2000 or so) for recovering all three gasses.
Fig ___ Oxygen and Nitrogen recovery plant
Fig ___ A BOC bogie gas tanker from the 1960s
Fig ___ A Distillers Co Carbon Dioxide tanker from the mid 1970s
Arcton and Freon
Arcton (once an important refrigerant gas but no longer used for that purpose) is made by treating fluorspar rock (calcium fluoride) with concentrated sulphuric acid to produce hydrofluoric acid, this is then treated with chloroform and super-heated steam to produce chlorodifluoromethane, also called HCFC-22 or Arcton-22. The ICI arcton plant was at Runcorn (now owned and operated by a Japanese company, Asahi Glass Fluoropolymers).
Arcton was shipped in tank wagons and the ICI operated arcton (refrigerant) ferry tank are further discussed in the section on 'Kit Bashing' in the subsection 'K Various types of unusual tank wagons'. I believe they operated from the later 1950s until the 1980s.
Fig ___ ICI Arcton tank
The gas was stored in pressurised tanks, which seem to have been a fairly standard design for pressurised gasses in the UK. These tanks are generally large horizontal types and the basic size and shape seems to have been fairly standard at about 12 foot diameter (4m) 35-60ft (10- 18m) long (occasionally 80 ft but these were rare). The only photo I have was supplied by Graham Davies, it shows the arcton gas tanks at the Runcorn ICI plant.
Fig ___ Arcton pressurised gas tanks
Arcton is no longer used as a refrigerant but it is used to make PTFE (polyetrafluoroethene). During World War Two ICI obtained the UK manufacturing rights for PTFE, also called Teflon (ICI call it 'Fluon') and set up a plant to make it at Hillhouse near Blackpool.
Alcohols are important industrial chemicals, the two most important are ethanol and methanol but other industrially useful alcohols include Ethane-1 ,2-diol (Ethylene glycol), Propane-1 ,2,3-triol (Glycerin) and 2 - (2-propyl)-5-methyl-cyclohexane-1-ol (better known as Menthol). Alcohols have a number of industrial uses, for example 50/50 solution of ethylene glycol and water is commonly used as an antifreeze in engine cooling systems and ethanol is used to make hand washing gel which sterilises the skin but evaporates so you don't need a towel after washing your hands. Alcohols are generally useful as solvents and can be used as a fuel for internal combustion engines (discussed below).
Ethanol is also known as ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol and it is usually made by fermenting something sugary in the same way alcoholic drinks are made. For industrial use it is also produced from ethanol at oil refineries (since the 1930s I believe). The industrial stuff is near pure (and deadly in undiluted form). As it is 'drinkable' ethanol is subject to taxation in the same way that beer wine and spirits are taxed, so it is usual to add a non-drinkable alcohol to it for industrial purposes. One common additive is methanol which renders the liquid poisonous. Ethanol with these additives is called denatured alcohol, when methanol is used it may be referred to as methylated spirits ('Meths') or 'surgical spirits'. Industrially ethanol is both an essential solvent and a feedstock for the synthesis of other products, notably ethyl halides, ethyl esters, diethyl ether, acetic acid, butadiene, and ethyl amines.
Methanol is technically called isopropyl alcohol but often called wood alcohol as the main source used to be wood distillation or pyrolysis (see also Lineside Industries - Chemical Industries - Wood Tar Distillers). It can also be made from black liquor from pulp and paper mills. It was first produced in a pure form by Robert Boyle in the 1660s. You cannot drink methanol, just 10 ml will cause blindness, and as little as 100 ml will kill you.
Up to the 1920s all supplies were obtained from wood distillation but then the Germans worked out how to synthesise it, this involved using very high temperatures and pressures and am expensive catalyst, so wood distillation remained an important source. By the 1930s it was being produced from coal gas but the process involves some serious plant and it was probably the 1940s when coal gas and LNG became the principal sources. More recently methanol production has made use of better catalysts and operate at lower pressures, in the later 1960s ICI developed the most common modern technique, called 'low pressure methanol' or LPM.
In the post World War two era methanol has been associated with refineries where it is made using LPG. A typical petroleum gas based methanol plant is a classic 'tall silver towers' installation with a lot of associated pipework. They tend to be long rectangular installations, the illustration below has been altered to reduce the width by about 50 percent. This still has all the essential elements but it would take a lot of bent metal wire for the pipework.
Fig ___ LPG based methanol plant
Methanol is widely used for a number of industrial processes, LPG plants use it to melt ice that forms inside the plant when water gets inside but its main use is in making formaldehyde (which is then used to make a range of other products). It has been transported in rail tanks since the 1930s (possibly earlier), it is a Class A liquid.
Fig ___ ICI Class A tank wagon for Methanol (pre World War Two)
Alcohol as fuel
Ethanol has often been used as a fuel, the original Model T Ford was designed to run on it as the farmers could make their own fuel. That was stopped by the Prohibition act in the USA and the oil companies then put a lot of effort into discouraging its use thereafter. When the oil crisis of the 1970s pushed up the cost of petrol people began looking at methanol as a fuel, in the USA the auto makers produced a range of vehicles which can run on a petrol-alcohol mix, mainly using methanol. This fell from favour in the 1990s when the cost of methanol went up but in the 1970s and 1980s it was used to make the petrol additive methyl tert-butyl ether (MTBE) as a replacement for tetraethyl lead. More recently (as the oil supplies have started to reduce) alcohols are again being considered as a fuel, but this focuses on fermented vegetable matter which would consume grain and would mean large parts of the world starving (which might be politically sensitive).
Odds and ends - Small scale chemical manufacturing
Up to about 1800 alum was an important mordant, used in dying cloth. The UK originally imported supplies but in the 17th century a group of engineers from Italy were persuaded to come to England to set up alum production. An industry was founded, mainly in Yorkshire, to process the shale mined along the coastline, which contained the key ingredient, aluminium sulfate. This material was also found in the shale waste from coal mines and at Pleasington in Lancashire they mined it just to make the alum. To process the shale it required ten tons of coal per ton of alum, the shale and coal were piled up and set alight, being left to burn for several days. The white ash left behind was the required material which was then processed with stale urine brought in by ship from London and Hull (the first public urinals in Hull were built as collecting points for this trade).
A new process to recover small amounts of alum from the shale using sulphuric acid was invented in 1850, adding to the demands on the acid manufactures. An alum factory might be quite small, traffic inwards would be shale from a local coal mine and sulphuric acid in glass carboys or iron tanks, outgoing would be sacks of alum.
Whitby became a rich town on the back of the alum trade but alum was replaced by mordants obtained from coal tar and production from shale was wound up by the 1890s.
The railway involvement in Yorkshire coastal alum manufacture was I believe nil, the stuff was made on the coast and transport by ship was convenient and cheap. However the works were distinctive and for a pre-grouping layout they can be used to add some local flavour to a coastal line in Yorkshire.
The companies listed below are considered typical for their respective industries.
In the listing below I have tried to include all companies operating branded chemical carrying railway rolling stock in the UK. There have been, and are, an awful lot of chemical companies out there and more examples will get added to this sub section over time.
Imperial Chemical Industries (ICI) By the early 1920s the German chemical dye firms had merged into a single entity called IG Farben (prior to its dissolution after World War it was fourth-largest company in the world, after General Motors, US Steel and Standard Oil) and in America Du Pont was dominating the chemical industry. British firms were worried about this and formed ICI in 1926 to protect their interests. ICI was created by merging four existing companies; The United Alkali Company, Brunner Mond, Nobel Explosives and British Dyestuffs Corporation. ICI were by far the biggest UK chemicals company, producing chemicals, explosives, fertilisers, insecticides, dyestuff's, non-ferrous metals, and paints. The main production plants were:
Billingham and Wilton (on Teesside). Initially this site produced fertilisers but from the mid 1930s it also produced plastics. During World War II it manufactured synthetic ammonia for explosives. The various works in this area were merged in the 1960s to form ICI Heavy Organic Chemicals Division and ICI Agricultural Division.
The works at Blackley, near Manchester, produced dyestuff's. When the company was divided into divisions in the 1960s this became the ICI Dyestuffs Division and at various times it was combined with other specialty chemicals businesses and became ICI Colours and Fine Chemicals and then ICI Specialties.
The site at Runcorn not far from Liverpool but in Cheshire, produced chlorine and caustic soda. In the 1960s it became ICI Mond Division but later became part of the ICI Chemicals and Polymers Division.
ICI operated a wide range of rolling stock, they had the bogie hoppers bringing limestone down from Buxton to Northwich (replacing a fleet of wooden bodied standard 4 wheel wagons), quite a few wooden open wagons, a few vans and a number of chemical tank wagons (see under Chlorine above). The example below was built in the later 1950s and used for Arcton (a refrigerant), this was heavy so the tank was small. The wagon is equipped for ferry operation and has the standard ferry fittings and ID plate on the right hand end of the chassis. Modelling this wagon in N is discussed in the section on Kit Bashing.
Fig ___ ICI Arcton tank
A pre-war ICI methanol tank is illustrated in the section 'Lineside Industries - Petroleum and LPG'.
From 1944 ICIs manufacturing interests in the United Kingdom were organised in a number of Divisions, each of which was responsible for the manufacture and sale of a group of related production. The Divisions operated over 100 works in the United Kingdom making 12,000 different products. Though they varied considerably in size, even the smallest Division was a substantial enterprise. The core of the business was bulk chemicals but from the later 1960s there was a shift in emphasis toward the higher value products such as pharmaceuticals.
Fig ___ ICI logo
In 1991 Brunner Mond Holdings Limited was formed by the break-off of the UK and Kenyan soda ash businesses from ICI, recreating Brunner Mond as an independent company (see also Brunner Mond below). In 1993 the pharmaceuticals, agrochemicals, specialities, seeds and biological products were placed into a new and independent company called Zeneca Group (which merged with Astra AB in 1999 to form AstraZeneca PLC, one of the largest pharmaceutical companies in the world). Finally the Dutch firm Akzo Nobel (owner of Crown Berger paints) took over the now much reduced ICI itself in June 2007.
United Alkali Company Limited United Alkali was a British chemical company formed in 1890 by Charles Tennant. The firm produced soda ash by the Leblanc process, which was sold to the glass, textile, soap, and paper industries. Tennant also set up a number of other companies (see also under Tennants Consolidated Ltd below) but United Alkali Co became part of ICI in 1926.
Fig ___ United Alkali logo
A soda ash company set up in 1873 by John Brunner and Ludwig Mond and based at Winnington near Northwich, Cheshire they produced their first soda ash in 1874 using the then new Solvay ammonia process. In 1924 Brunner Mond acquired the Magadi Soda Company of Kenya and in 1926 Brunner Mond merged with three other British chemical companies to form Imperial Chemical Industries. The famous ICI limestone hoppers were used to supply the Brunner Mond plant in Cheshire, as of 2008 the trains still run but the wagons are modern high capacity hoppers. In 1991 Brunner Mond Holdings Limited was formed by the break-off of the UK and Kenyan soda ash businesses from ICI, recreating Brunner Mond as an independent company. After this time the Brunner Mond branding was applied to the large hopper wagons carrying limestone. Brunner Mond was purchased by the Indian giant Tata Chemicals in 2006.
Fig ___ Original and post ICI Brunner Mond logos
British Dyestuffs Corporation Ltd was a British company formed in 1919. The British Government was the company's largest shareholder, and had two directors on the board. The organisation was created because, prior to World War One, British industry had relied on Germany for 89 percent of its dyes, and much of the remainder relied on German produced feed stocks. This caused problems during the war and the plan was to address this shortcoming. To start with the Corporation bought out other firms notably Read Holliday and Sons of Huddersfield. The company supplied a comprehensive range of dyes within a competitive market, its most notable foreign competitors were Du Pont and IG Farben. It became part of ICI in 1926.
Fig ___ British Dyestuffs Corporation logo
Nobel Industries Limited
The British Dynamite Co. Ltd. was formed in 1870 by Alfred Nobel to produce and market his new explosive 'dynamite'. The name changed to Nobel's Explosives Co. Ltd. in 1976. After the first world war several important concerns were merged with Nobel's Explosives Co. Ltd. to form a new company called Explosives Trades Ltd., later renamed Nobel Industries Ltd.
This company was one of the original members of ICI when it was formed in 1926, becoming ICI Explosives Division. In 1948 the Division was renamed the Nobel Division because by this time it was producing a range of materials which, although logically allied to explosives manufacture, were not them-selves explosive in character. This included a wide range of industrial nitrocelluloses, a basic raw material in the manufacture of paint, lacquers and leather-cloth and also a range of acids, chiefly sulphuric acid, together with a number of heavy and fine chemicals. Following the de-merger of ICI in the early 1990s this company was purchased by Inabata & Company (a Japanese trading firm). This company is more fully discussed in the section on Explosives and Fireworks Industries as that was their business.
Fig ___ Nobel Industries logo
Chance and Hunt
A chemical company based in Oldbury they produced a range of chemical products including soda ash and sulfuric and hydrochloric acid. They were established in the early 19th century as a branch of Chance Bros the glass makers of Smethwick to make chemicals for the glass works. They expanded their range of chemical to include sulphuric acid (by the chamber process), saltcake, hydrochloric acid and soda ash (described above) and by the 1850s they were also selling sal ammoniac and ammonium carbonate.
In the 1870s they worked out how to recover the sulphur from the waste of the Le Blanc soda ash process and in the 1890s the name changed from Chance Bros to The Oldbury Alkali Co Ltd. and then to Chance and Hunt. They made TNT during World War One but the firm was controlled by Brunner Mond by the end of the war.
Fig ___ A Chance and Hunt 'acid jar' wagon
When ICI was formed Chance and Hunt became part of that organisation but continued to trade under their old name for certain products until 1939, when they became the Chance and Hunt Department of ICI Mond Division. Their main operations at this time were centred on the Oldbury works with a second works set up at Wednesbury, Staffordshire.
The firm owned salt works in Stafford, the salt being used to make the soda, and operated some salt wagons in their own livery.
Fig ___ Chance & Hunt salt wagon
In the later 1960s a large part of the Oldbury works was taken up by the new motorway and it became just a distribution depot. In 1999 amidst the de-merger of ICI the management bought the company, which became Chance and Hunt Limited, in 2002 they joined the multi-national Azelis group of companies. As of 2008 they were producing a wide range of chemicals from agricultural fertilisers to a range of adhesives and resins.
Albright and Wilson
A major British chemical company, ranked second only to ICI in the UK chemical industry (although much smaller), it was founded in 1856 as a manufacturer of potassium chlorate and white phosphorus for the match industry. Specialising in the field of phosphorus chemistry it was the world's biggest supplier of phosphates for detergents. They operated large sites initially at Oldbury near Birmingham and subsequently additional plants at Avonmouth near Bristol and on the Mersey near Liverpool.
In 1955 Albright and Wilson took over the Marchon Chemical Company based in Whitehaven, which produced phosphorus-based detergents by the "wet" process. The track plan shown under Modelling A Chemical Works above is based on this installation.
The phosphate detergent business rapidly declined in the later 1970s due to problems it was causing in the environment. This lead to a near collapse of the company which was then rescued by a deal with Tenneco Inc. (an American oil company) in 1971.
White phosphorus continued in production at Oldbury until 1972 when production was moved to Newfoundland. The white phosphorous was shipped back to the UK in bulk tankers, discharging at Portishead in Somerset. Although wholly-owned by Tenneco from 1978, Albright & Wilson retained its identity and management until it was divested by a public offering in 1995, as a part of the break-up of Tenneco. The move of the white phosphorous plant to Canada was beset by management failures and caused a slump in profits and in 1999 the company was absorbed by the French chemical company Rhodia (the Whitehaven Marchon plant had ceased production in the 1980s, the name ceased to exist when Rhodia took over). Parts of the original Albright and Wilson company are now owned by the Huntsman Corporation.
Peco offer a tank wagon in Albright & Wilson livery lettered for carrying phosphoric acid, this can be used on layouts from the mid 60s (when the tank type was introduced) until 2000 or shortly thereafter (when A&W was bought out by Rhodia). Note that phosphoric acid tanks are usually heavily stained with white in service. This company used a range of chemicals, including liquid chlorine (supplied to their Oldbury works in tankers, I believe by ICI).
Fig ___ Albright & Wilson Logo (as used from 1960s) and Hornby tank
In 1986 Albright & Wilson Limited closed the internal railway system at their Marchon Works at Whitehaven, which included the cable worked incline known as the 'Corkickle Brake'. I believe this was the last working standard gauge cable-hauled incline in the UK.
Castner-Kellner Alkali Co. Ltd
This firm was the lineal descendent of the chemical factory set up in Liverpool by James Muspratt in the year 1822. It was at the Castner-Kellner Works at Runcorn that a new field in chemical manufacture opened when H. Y. Castner's electrolytic chlorine process was first established there in the later 19th century. The firm became closely involved with Brunner Mond and was one of the companies that formed ICI in 1926 but the brand remained in use for many years thereafter.
Murgatroyd's Salt & Chemical Co. Ltd.
Murgattroyds had been in the salt business since the 1890s but the Murgatroyd Salt and Chemical works at Sandbach began operations in 1950, primarily to supply the Stavely Iron and Chemical Co. with caustic soda. In the mid 1950s there were a number of four wheeled and small bogie tankers built for Murgatroyds to carry liquid chlorine, Tri-ang used to offer a model of the bogie type (although this had diamond frame bogies and should have had the plate frame type). The rough sketch below is what I believe the Murgatroyd's livery may have been (this was before the introduction of the horizontal orange band for compressed gasses), I must stress there is a lot of guesswork in this, not least because it is based on the old Triang model.
Fig ___ Murgatroyd's chlorine gas tank
Paul Bartlett's excellent 'fotopic' site (see bibliography - photo sites) has a collection of photos of these wagons in their later BP era livery.
Joseph Crosfield and Sons Ltd.
This firm had many wide ranging interests centred on its soap production business however it also sold quantities of Silicate of soda.
Izal was a subsidiary of Newton, Chambers and Co (founded in 1789 who operated coal mines and iron works). Izal was a disinfectant business, utilising the products of coal distillation at the coke works of the Newton Chambers steel works next door, they advertised their products as being 'non poisonous' (a rare claim for disinfectants). Izal, based at Thorncliffe near Sheffield, it was formed some time before the First World War and made extensive use of rail transport (Bachmann offer a coal wagon in OO). Shortly before that war Izal built some tank wagons (at least 6). I am unsure what these were for as Izal would generally obtain the distillates from the adjoining works of their parent company, these tanks may have been for distributing industrial quantities of their disinfectants.
Fig ___ Izal tank and coal wagon liveries
At the time Izal was offering 'Disinfectant Fluids and Powders, Insecticidal Fluids and Powders, Liquid Soaps, Cleansers, Antiseptic Toilet Rolls, etc.'. Prior to World War Two Izal toilet paper was standard in schools and hospitals, that supplied to schools had nursery rhymes printed on it, during World War Two this changed to a caricature of Hitler. During the war the engineering side of the business built over 1000 Churchill tanks. By the 1960s Izal were listed as 'Specialists in the manufacture of various germicides including Izal, Sanizal, Zalpine toilet rolls' and they also produced Ronuk floor polish at the Izal plant (after buying out the Brighton based firm in the mid to late 1960s). Newton Chambers and Co were taken over by industrial holding company Central and Sheerwood in 1972.
Associated Ethyl from 1961 Associated Octel This organisation started as a government project in the later 1930s, with war looming they needed home produced sources of additives for high performance engines. At the time the UK was importing tetra ethyl lead (TEL) and dibromoethane (DBE) from the USA. As a precaution the British built a government owned TEL plant at Northwich in Cheshire and a DBE plant at Hayle in Cornwall, both came on stream in 1940. In the early 1950s a new DBE plant was built at Amlwch (Bromine is recovered from seawater, but it takes 22,000 tons of seawater to produce 1 ton of bromine), I think the Hayle plant closed at about this time. Somewhere about this time these Government owned plants were purchased by private chemical companies, and a new company was formed to run them called The Associated Ethyl Company Limited, the name changed to The Associated Octel Company limited in 1961. This company also set up a plant at Ellesmere Port in Cheshire in 1940 (I think this was another TEL plant). All these plants were rail connected and a daily tank train ran between Ellesmere Port and Amlwch ran from the 1950s until 1993. The tank wagons carried either ethylene dibromide, in plain grey tank wagons, and the liquid chlorine in gas tank wagons. Given the dangerous nature of the cargo the train had barrier vehicles and (oddly) a brake van at each end of the rake (I am not sure why two vans were used).
At the Amlwch end there were a set of loops that served as an exchange siding and a works loco took the tanks into the plant (looked a bit like the BR class 03), once diesel engines took over they worked right into the plant themselves. The Amlwch plant closed in 2003 but rail services had ended in the early 1990s.
To shift the TEL they have used a number of 'demountable' tanks (transported on railway company owned 'conflat' wagons) as well as rather some 'continental' looking rail tank wagons (built to full RIV ferry specifications, there are some wagons in the Continental ranges that would serve). Some of the containers did not have the difficult to replicate logo, an example is shown below. This horizontal type had a dove grey tank and is not difficult to model (the tanks from the W&T twin-gas tank kit make a fair starting point). Some of these tanks were carried on standard BR conflat wagons (I think some had purpose built chassis, still owned by BR, but these may just have been older pre-nationalisation container flats).
Fig ___ Associated Octel TEL demountable tank
This company used an octagonal logo on some containers and their tank wagons which is difficult to replicate. Early examples were orange and had the word Ethyl in them, by the early 1960 they were blue on a white background with Octel on them. The logo was only used on some of the demountable tanks, these were basically a vertical cylinder and hence not too difficult to model. They were white so a printed wrapper made on a computer could be used (these tanks also had a large orange and black data panel on the side which would be near impossible to do by hand in N).
Fig ___ Associated Octel blue logo
In 2007 Associated Octel became Innospec, it remains a world scale chemicals company specialising in fuel additives.
British Oxygen Company The British Oxygen Company began life in the mid 1880's when two French brothers by the name of Brin developed a new method of obtaining oxygen by heating barium oxide and set up Brin's Oxygen Company. The main use for oxygen at the time was 'lime light' in theatres but the company promoted its use in sugar bleaching, preserving milk, making saccharine, vinegar and linoleum, maturing whiskey and in iron and steel manufacture.
Particularly profitable were fizzy oxygenated drinks.
Early distribution was in cloth 'gas bags' but iron cylinders soon followed. The problem with these was that the cylinder weighed and cost a lot more than the gas it contained which restricted the practical distribution. In the later 1880's Brin's therefore began licensing a number of producers throughout the country and in 1890 they patented a new steel cylinder which soon became the international standard. Brin's also expanded into making fittings for these cylinders.
At about the turn of the century a new method of obtaining oxygen direct from the air was independently developed in Britain, Germany and the United States, as often seems to have happened the German team headed by Dr. Carl von Linde reached the patent office first. By 1906 Brin's had obtained a licence to make oxygen using the new system, they abandoned their now outmoded method and changed their name to British Oxygen Company Limited.
There followed a steady expansion as new uses for oxygen were developed, notably in welding and cutting, and with the coming of War in 1914 BOC production was dramatically ramped up to meet the demands of the armament manufacturers.
In the post war years BOC continued to expand, buying up smaller firms and further developing production of acetylene and 'rare gasses' (argon, krypton, neon, xenon and helium). The latter were mainly used for their inert chemical properties for filling various kinds of light fittings and lamps but also in hospital anaesthetics. In 1920 BOC bought Sparklets, who made small cylinders of carbon dioxide for soda siphons, and in 1930 BOC merged with a South African company with whom they had worked on developing oxy-acetylene cutting and welding equipment.
In 1935 BOC designed the Queen Charlotte's Gas-Air Analgesia Apparatus, and in 1936 they introduced Entonox, a new analgesic gas for use in childbirth and in ambulances. In the same year BOC built the first 'ring main' system for distributing oxygen to hospital beds and theatres. At this time they established a new Medical division and produced what was to become the standard gas-air anaesthetic apparatus for use in hospitals.
All medical gases were distributed in steel cylinders
In 1936 BOC expanded its interests in welding by buying Quasi-Arc Co, who had developed improved electrical welding electrodes.
The second world war placed demands on the company, the Sparklets subsidiary in particular developed its little gas bottles into a great range of types for everything from inflating life-jackets to releasing ether into aircraft engines to help them start in sub zero temperatures.
The 1950's saw a major competitor arrive in Britain, the American company Air Products but this was coupled with a dramatic increase in the demand for steel, which required a lot of oxygen. The old methods of shipping the gas in pressurised tanks could in no way meet the demands of the new furnaces and BOC pioneered the development of on-site oxygen production, supplying oxygen by the ton. Other customers for this 'tonnage oxygen' included Wimpey, who used it for rocket motor testing, and as a fuel for the Thor and Blue Streak missiles.
Nitrogen was originally used in electric light bulbs, also for making Ammonia (Haber Process) and up to the 1940's for making Nitric Acid (Birkeland-Eyde Process). Demand increased with the development of flash or freeze drying and in the 1960's BOC set up a joint venture with Linde AG of Germany.
The 1960's and 70's saw a wide ranging diversification of BOC in spite of a scathing report by the Monopolies & Mergers Commission who claimed they were over charging clients (non of the clients had complained however). They went into fatty acid production, resins and adhesives.
Fig ___ A BOC bogie gas tanker from the 1960s
One major area of interest remained gas welding and cutting and BOC were at the forefront of underwater technology that became so important with the development of the North Sea oil fields. In 1978, after years of negotiation with the American authorities, BOC bought the American firm Airco. This doubled the size of BOC and prompted a name change to BOC Group.
In 2006 BOC was bought by the German Linde AG group, which then became the worlds largest gas producing company.
The British Cyanides Company Limited formed in about 1880 as a joint venture by Albright and Wilson and Chance and Hunt to exploit a new process for extracting gold from low-grade ore. Both companies produced cyanide already and their joint subsidiary was established on land between the two existing firms premises in Oldbury near Birmingham. Their main customer was South Africa, but in 1900 the Boer War broke out this market disappeared overnight. They tried a range of products including ferro-cyanide (from sulpho-cyanide using purssiate of soda) . In 1904 they came up with a better method of making cyanide and the company was re-launched and then went into using the barium process to fix nitrogen from the air and produced cyanogen, from which they made sodium cyanide. In World War One they made sodium manganate for gas masks and during the war they set up a potash plant (used to make high quality glass for the Admiralty) and after the war they also made prussate of soda. They were listed a few years later as making 'Yellow Prussiates of Soda and Potash, Carbonate and Bicarbonate of Potash, Permanganate of Potash'. They tried using sulpho-cyanide to make thiourea for use in silk and tafeta but those materials went out of fashion in the later 1920s but in 1924 they had patented a method for making urea-formaldehide resins by condensing thiourea with formaldehyde to produce water-white resins with which they produced 'moulding powders' (powder mixed with the resin, an early form of plastics). Thereafter they were increasingly involved in the plastics business, their history and the later formation of British Industrial Plastics is discussed separately under Plastics Manufacturers.
Tennants Consolidated Ltd
Tennants can trace its origins back to the late 1700's when the founder Charles Tennant, the son of a farmer and apprenticed as a Weaver invented bleaching powder ((chloride of lime) by passing chlorine gas over slaked lime to form bleaching powder, a mixture comprised of calcium hypochlorite and other derivatives. This seemingly insignificant discovery revolutionised the linen trade by substantially reducing the time, effort and cost involved in the bleaching of cloth prior to dyeing. Tennant Consolidated Limited was established in 1797 and a huge chemical business was spawned centred on St Rollux, a suburb of Glasgow. Tennant had already worked with the chemist Charles Macintosh and helped establish Scotland's first alum works at Hurlet, Renfrewshire. The chemical business founded by Tennant became known as the United Alkali Company Ltd. and this part of the Tennants business empire merged with others in 1926 to form the chemical giant Imperial Chemical Industries. The chemical works at Springburn closed in 1964. Tennants Consolidated Ltd continued to exist outside the ICI structure, it remains today (2008) a major industrial group with wide ranging interests, its headquarters remains in Glasgow and it owns a factory in Maryhill operating under its name (as well as many subsidiary companies).
A manufacturer of floor polishes and wood treatments based in Brighton, I am not sure when they set up but they were definitely up and running in 1907. They produced a range of polishes and waxes (highly regarded in hospitals for their germicidal properties) and developed the Ronseal range and Colron wood dyes in the 1950s. Ronuk operated several railway tanks and models in their pleasingly different livery have appeared from time to time. I believe the tank pre-dates Ronseal, however there are two main types of polish (liquid and wax) and there are also solvents (mainly turpentine produced at Wood Tar Distillers) involved in some polishes. The advertising for the Airfix model of a Ronuk tank suggested it carried 'white spirit' (a petroleum distillate that is often used as a cheap substitute for turpentine), however white spirit is a Class B liquid (flash point above 23 deg C and below 60 deg C) , so these tanks should have been red oxide to conform to the rules. It may have carried turpentine (a solution of resins distilled from the sap of conifers, used in varnish and as a paint solvent, in this case it would serve as a solvent for the wax in the polish), this can fall outside the Class B specification depending on the exact 'mix'. It may have been used to ship bulk liquid wax to a bottling plant.
Fig ___ RONUK tank
Ronuk was purchased by Izal Ltd in the late 1960s (see Izal above). Ronuk then became a separate sales division of Izal in 1970 (trading as Roncraft), and was bought three years later by the Sterling Drug Company.
In 1989, Sterling was bought by Eastman Kodak until the multinational photographic company sold all of its do-it-yourself business to Forstmann Little & Co. in 1994. The New York-based investment bank renamed the company to Ronseal Ltd and sold it to Sherwin-Williams in 1997. Ronseal is based at Thorncliffe Park in Sheffield in the UK and also has a thriving business in Dublin, Republic of Ireland.
Chemical & Metallurgical Corporation Ltd.
This company was incorporated in 1919 and was taken over by ICI in 1933, eventually becoming part of the Mond division of ICI. They operated a fleet of chemical tank wagons (they ordered 30 in 1928, one of which was number 133, but they presumably also had a number of open wagons for coal and their other products). These tanks had a twelve foot wheelbase and (although for 'chemicals') had standard size tanks, six feet four inches in diameter and twenty one feet six inches long. Peco offer a model in this livery but based on their ten foot wheelbase tank, however this the company may have operated some tanks of this size and the Peco model does resemble the longer wagons in general outline.
Fig ___ CMC Logo
The head Office was listed as being in London and their works were at Stratford (E London), Harlesden (Middx) and Astmoor (Runcorn, Cheshire), the 'return to' instruction on the Runcorn tanks read 'Return when empty to Astmoor Works Sidings, Via Warrington and Acton Grange, (Manchester Ship Canal Rly)'. It is likely that these tank wagons continued in use in their original livery for many years after the take over by ICI.