Zinc JJesilrcrizatioii. 81 



V. — On Zinc Desiloerlzation, 



BY T. EGLEHTOK, PH. D. 

 Read January 7th. 1878. (and revised to June, 1880). 



When lead ores contain silver, or when it occurs in 

 other ores in districts where lead ores can be had, they are 

 smelted alone or together and the silver afterwards separated from 

 the lead. The silver is either extracted on the spot or more gen- 

 erally sent to the East to be separated there. This material is 

 called "base bullion," a very improper name, since it is not bul- 

 lion at all, but only argentiferous or work-lead; and although this 

 term is current in the West, it should not be adopted in techni- 

 cal literature. The furnaces in which the ores are smelted are 

 almost invariably shaft-furnaces, as the ores are very silicious, 

 and the process used is that of direct or indirect precipitation. 

 The furnaces are usually water-Jacketed and generally provided 

 with Arendt's tap. The works which treat these ores are situ- 

 ated for the most part in Nevada, Utah and Colorado. A few 

 furnaces have been erected in the East, as at St. Louis, Mans- 

 field Valley near Pittsburgh, and in the vicinity of New York ; 

 but, as a general thing, it will not pay to transport the ores 

 which come from all the Western territories, to the East, when 

 there are works competing for them at home, unless they are 

 exceedingly rich, or there is some special business reason why 

 they should be treated here. 



It is not proposed to give a description of the process of smelt- 

 ing, which in many respects is peculiar to the West, but only 

 some peculiarities with regard to a few of the works from which 

 the details of desilverization have been taken. These are the 

 Germania Works, Salt Lake, the works of the St. Louis Smelt- 

 ing and Refining Company, at Cheltenham, Mo., and those of 

 the .Pennsylvania Lead Co., at Mansfield Valley, near Pitts- 

 burgh, Penn. 



The Western works treat ores which come jirincipally from 



