1865.] MACFARLANE — EXTRACTION OF COPPER. 243 



the furnace a spray-wheel and chamber such as described by Whelp- 

 ley and Storer as being attached to their pulveriser. In contact 

 with the.water, these gases would form dilute sulphuric and hydro- 

 chloric acids, the further treatment and separation of which would 

 be matters of comparative ease. 



The best method of treating the solution obtained by lixiviat. 

 ing the calcined product would probably be simply to acidify the 

 solution slightly, and precipitate while warm with metallic iron. 

 The resulting copper would, after washing, be almost chemically 

 pure ; and in all likelihood, by compressing it into cakes and fusing 

 it in crucibles, a pure product might be obtained. The residual 

 solution after the precipitation would, on evaporation, yield large 

 quantities of sulphate of soda. The cost of the manipulation 

 connected with the lixiviation, etc., would probably not be less 

 than $1.50 per ton; and if we include the production of the 

 sulphate' of soda, it would probably be raised to $2.50 per ton. 



Although it is altogether impossible to give any reliable 

 estimates with regard to be cost of a process which has not been 

 tried on a large scale, yet it may be as well to attempt a calcula- 

 tion as to the cost and proceeds of this method of extraction, in 

 order to ascertain as to whether it is economically feasible. The 

 expenditure on the operation might be estimated as follows : 



One ton of 7 per cent ore ($2.25 per unit on 6| per cent).$14 62 



Crushing 10 



Pulverising 20 



Calcining ! 00 



Lixiviating, &c 2 50 



Refining the precipitated copper to ingot 2 00 



Concentrating the sulphuric and muriatic acids 3 00 



500 lbs. salt 2 00 



130 lbs. iron q 00 



$31.42 

 The following sums might be realized for the various products : 

 130 lbs. ingot copper (supposing 6 per cent only to be ob- 

 tained from 7 per cent ore), at 22 cents $26 40 



979 lbs. dry sulphate of soda (supposing only one third of 

 the sulphur to be recoverable iu this form),at 1 cent per 



lb. (6s. sterling is its value in England) 9 79 



660 lbs. sulphuric acid (supposing another third to be re- 

 coverable in this form), at 2 cent, per lb. (1 penny per 



lb. being its value in England) 23 20 



1188 lbs. muriatic acid, at 2 cents 5 $± 



$55 33 



