^12 Scientific Proceedings, Royal Dublin Soc%eiy. 



General Remarks on the '-'Hydro-Metallurgical" Treat- 

 ment OF Copper Ores. 



Since "wet methods" for treating poor copper ores and the 

 residue from the sulphuric acid burners have been received with 

 more favour, numerous improvements in the details of the general 

 treatment have been proposed and numerous processes have been 

 introduced to meet the peculiarities and circumstances of each 

 particular case. 



Each of these processes usually consists of three principal 

 operations, the treatment iu one or more of these operations 

 varying so as to produce a variety of processes. 



It is unnecessary here to describe these processes* in detail, 

 but in speaking of the general treatment, we may notice the 

 more interesting modifications that have been proposed. 



In the general treatment of ores by wet or hydrometallurgical 

 methods three stages or principal operations are recognisable. 



I. Treatment of the Ore (Generally sulphide). — In order to 

 render the copper salts soluble in water, in dilute acid, or in 

 a solution of some salt, 



II. Solution of the Copper Salts (as chloride or sulphate), 

 and sometimes the purification of the solution, by removing either 

 the more valuable or the more injurious ingredients. 



III. Precipitation of the Copper (usually as the metal or 

 as sulphide), and often an after treatment of the liquors for the 

 recovery of the other salts in solution. 



The last operation or precipitation is that in which we are 

 more particularly interested, but it seems desirable to consider 

 something of the previous treatment of the ore and copper solution. 



Treatment of the Raw Ore. — The ores usually treated are 

 either oxides, carbonates, or sulphides, of copper. Oxides and 

 carbonates are generally treated with a solution either of a 

 chloride or of an acid. They are, however, sometimes roasted 

 with the former. Sulphides are of more common occurrence, and 



* The more important of these processes are described in our Standard Metallurgical 

 Works, from which much of the following has been compiled, such as Percy's ; Crookes and 

 Rohrig'sadaptationof Kerl's work ; Phillips'; Greenwood's. An admirable reszmie of the more 

 recent " wet methods" will be found in Dingler's Polytechuisches Journal, 1879, Band. 

 231, pp. 254, 357, and 428. Also Proceedings Roy. Soc, New South Wales, 1876. Vol. X., 

 page 135, reprinted in Iron, 1879, page 76, and translated into Bulletin de la Societe 

 d'Encouragement, (1878), Series 3, Vol. V., page 612. 



