Manufacture blackpowder

Coming. In blackpowder manufacture, the stage of the process which produces uniform spherical grains. 

Mill cake. In blackpowder manufacture, a product taken from the edge runner mills. 

Later on the decomposition of cellulose at high temperature was examined by a number of authors. Most of the research was devoted to the problem of the origin of coal. The experiments of T. Urbanski at al. [50] using infra-red spectroscopic analysis for the examination of the products of thermal decomposition of cellulose are described in Vol. III. (Charcoal for blackpowder manufacture). 

In the manufacture of fast cord the first process is to coat paper or textile yarns with a blackpowder/nitrocellulose dope by a dipping process. These yarns are thoroughly dried and a number of them passed through an extruder and given a thick covering of plastic incendiary composition. The cord thus produced is covered with a protective layer of plastic, usually polyethylene. The overall diameter of the cord is about 2-5 mm. 

Most blackpowders contain 75% of potassium nitrate, 15% of charcoal and 10% of sulphur. For safety fuse, however, blackpowders are made with reduced amounts of potassium nitrate. Also manufactured are sulphurless powders, containing approximately 70% of potassium nitrate with 30% of charcoal. These sulphurless powders are used for ignition purposes where sulphur could cause corrosion of metallic components. 

During the beginning of the nineteenth century, the alkali and acid industries provided the model for other chemical industries. One characteristic of the chemical industry is that development in one area often stimulates development in another area. For example, the lead-chamber method produced enough sulfuric acid to make the acid practical for use in the LeBlanc process. Similarly, the Solvay process used ammonia produced when coke was made for steel production. Certain chemical industries were perceived by royalty and national leaders as critical to their nation s welfare. One of these was the manufacture of gunpowder, also known as blackpowder. Gunpowder is a mixture of approximately... 

The forerunner of all modern explosives, blackpowder, formerly often called gunpowder, is a mixture of potassium nitrate (saltpetre), sulphur and charcoal. The origin of blackpowder is obscure and dates back to very remote times. According to numerous historical works, in particular that of Romocki [1] blackpowder was invented by the Chinese many centuries B.C. The secret of its manufacture penetrated from there to Central Asia and was brought to Europe by the Arabs about the middle of the thirteenth century. 

Potassium nitrate is obtainable from natural deposits in hot countries e.g. Ceylon, Egypt, Mexico, India, Iran and some areas of the U.S.S.R. It occurs there as the result of the microbiological oxidation of organic nitro compounds and of the reaction of the products with the alkaline components of the soil. On being refined by crystallization such saltpetre was (and partly still is) used for the manufacture of blackpowder. In Great Britain for instance until relatively recently the only source of potassium nitrate was saltpetre from India. 

At one time potassium saltpetre was also obtained from manure and wood ash. Here potassium nitrate forms as a result of microbiological processes followed by reaction with potassium carbonate. Descriptions from various periods of history may also be found that refer to the collection of saltpetre from the walls of cellars situated in the vicinity of sewers. In this way, for instance, saltpetre was acquired in Poland for the manufacture of blackpowder during the insurrections of 1830 and 1863. 

Potassium saltpetre for the manufacture of blackpowder must be of high purity. The technical specification for the synthetic product according to the U.S.S.R. standard (GOST 1939-43) is summarized in Table 81. 

Technical specification for synthetic KNO3 used in the manufacture of blackpowder fGOST 1939-43)... 

According to Soviet Standards GOST 828-41 sodium saltpetre for the manufacture of blackpowder mixtures should contain not less than 98% NaN03 and less than 2% moisture. 

For the manufacture of blackpowder the sulphur used should be of highest purity, refined by distillation. Crude sulphur (which usually contains 2-5% of impurities) is distilled from retorts heated to a temperature of400°C. The receiver should be maintained at a temperature above 115°C (120-130°C), i.e. above the melting point of sulphur (114-115°C). Under these conditions the distillate condenses to a liquid which is then cast into sticks or blocks. This is the only form of sulphur suitable for the manufacture of blackpowder. If the receiver temperature is lower, the sulphur distilled from the retort condenses as flowers of sulphur which always contain a little S02) and even traces of H2S04 (the substance is easily oxidized due to its large surface area). Sulphur in this form is therefore slightly hygroscopic and acidic, and is unsuitable for the manufacture of blackpowder. 

It is very important to select a suitable type of wood for the manufacture of the charcoal used in blackpowder. It must be soft, but not resinous and should be prepared from white wood of such trees as alder, poplar, willow, hazel etc. Before carbonization the wood must be de-barked and cut into pieces 10-30 mm thick. In some countries where hemp is plentiful the stems of this plant are used for making charcoal. 

The methods of manufacture depend upon the trend of development traditional in a given factory or country. The variety of methods arises partly from the fact that the manufacture of blackpowder is highly dangerous so that different countries... 

This principle of mixing by means of suspended wheels was not introduced until the end of the nineteenth century before then the kneading process in edge runners was the most dangerous operation in the manufacture of blackpowder. Wooden... 

Blackpowder for the manufacture of propellent charges has long been obsolete although some types are still produced for other purposes. Thus the French cube powder, poudre C or poudre SP, is employed as an igniter in bag cartridges. 

The manufacture of blackpowder is one of the most dangerous in the production of explosives. 

Fig. 105. System for illuminating buildings in which blackpowder is manufactured.

In Great Britain they are frequently referred to as E.C. powder (this stands for Explosives Company, one of the early manufacturers in England). In the U.S.A. they are usually referred to as bulk powder, probably because they were loaded in bulk, volume for volume, with blackpowder. 

Swedish Bofors Industries began to manufacture blackpowder. 

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