258 JOSEPH M. SHEAHAN 



or Swedish process; reverberatory or English smelting; and 

 the converter or Bessemer process. 



The blast furnace process consists in roasting the ores 

 in special apphances, following this by smelting the roasted 

 product with coke or charcoal in blast furnaces. The series 

 of chemical reactions which result during this treatment 

 are too technical to set forth here, but the result is copper 

 matte, a mixture of copper, sub-sulphide and some of the 

 original impurities of the ore. 



This matte is then commonly enriched by partly calcin- 

 ing it and again smelting it in the blast furnace, although 

 this second process is not always employed. 



The matte then is roasted and then smelted with siUceous 

 fluxes in addition to the carbon which is used in the first smelt- 

 ing to produce coarse or black copper. 



In the reverberatory process the ore is first partly calcined 

 and then is smelted in a reverberatory furnace with a quartz 

 lining, with the addition of siliceous materials or ores if nec- 

 essary. The resulting matte then is concentrated by being 

 partly roasted and then smelted again in reverberatory fur- 

 naces. 



The matte resulting from the concentrating process is 

 converted into crude copper by partial roasting followed by 

 fusion in reverberatory furnaces. The converting process 

 is not applied to ores, but is usually employed to reduce to 

 coarse copper the matte produced by either the blast furnace 

 or the reverberatory method. This converting process 

 consists in blowing a highly subdivided stream of air under 

 pressure, through molten matte which is contained in a pear 

 shaped or cylindrical converter lined with quartz ore material. 

 The matte to be blown is first melted in cupolas and then 

 run into the converters. 



Wet methods of reduction consist in getting into aqueous 

 solution, by means of suitable solvents, the copper which 

 of necessity must occur in some combination suitable for 

 solution, and of precipitating it from these solutions by suit- 

 able precipitants. The precipitate thus secured is refined by 

 the dry process. The copper ores to which this wet proc- 

 ess is applied contain the copper in the form of oxide, car- 



