Processes for the Manufacture of Lead and Silver Azide

There are many chemical compounds which, when used appropriately, will perform the function of a primary explosive and transfer or amplify an initial stimulus to the degree required to initiate detonation in secondary explosives. In fact, a secondary explosive itself can be used, and the need for hazardous and expensive materials like the azides (in particular, lead azide) may be questioned. 

A similar selection process occurred within the family of inorganic azides soon after their discovery at the end of the nineteenth century. Silver azide was recognized as at least the equal of lead azide in performance, but lead has alii 

The trend in detonator and explosive-train design, which has continued into the 1970s, has been to smaller components, requiring decreased amounts and diameters of more efficient explosives. This trend itself has tended to emphasize the technological importance first of lead and then silver azide and to assure the continued modification of their properties by process development and control. 

While the finished products sought in different countries are usually quite similar, if not identical, in performance characteristics, somewhat different philosophies exist with respect to control of the manufacturing processes. Thus, in the United States the manufacture of lead azide for military purposes is not so rigorously specified as it is in Britain, and more emphasis is given to satisfactory performance in routine tests as the criterion for an acceptable product. This difference of emphasis, together with the smaller scale of production, have led to a greater standardization in Britain, not only of the processes but also of equipment, and the processes have been exported or licensed for use in several countries of Europe and in Asia and Australia. 

On the other hand a more thorough knowledge of the effect of process variables has been required in the United States both to contend with large fluctuations in the demand for materials and to understand the consequences of looser manufacturing specifications. Thus, although the processes introduced into the U.S.A. are often based on the Taylor processes, these have also evolved with distinguishing features. 

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Lead, silver, and mercury azides were all discovered in 1890-1891 by Curtius, but it was Hyronimus in 1907 who first obtained a (French) patent for the use of lead azide in the explosives industry. Following World War 1 interest in lead azide became more general as both the civilian and defense industries of Western Europe and the United States began to explore the use of the material [2]. It was during the 1920s and 1930s that it became more widely appreciated that lead azide is not only hazardous to handle but also hazardous to manufacture, and processes to reduce the difficulties were developed commercially and in ordnance factories to meet different specifications. 

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