LEACHING OF PRECIOUS METALS FROM COMPLEX SULPHIDE ORES——2.DIRECT LEACHING OF Cu SULFIDE CONCENTRATE BY ACIDIC THIOUREA SOLUTIONS
(1.Institute of Chemical Metallurgy; Academia Sinica; Beijing 100080
2.Institute of Technology; S—100044 Stockholm; Sweden)
2.Institute of Technology; S—100044 Stockholm; Sweden)
Abstract: Recovery of gold and silver from a sulphide concentrate by thiourea leaching was investigat- ed.The effects of various parameters on the process,such as oxidants,the initial concentration of thiourea and acidity in solutions as well as reaction temperature,were systematically exam- ined.From the results it was confirmed that(a)oxidants had no significant influence on the dis- solution of gold and silver at a fixed initial concentration of thiourea;(b)the initial concentra- tion of thiourea and acidity affected the dissolution rate only in the earliest period of leaching; (c)the rate of the process was controlled by reagent diffusion.The optimum operations were worked out for the thiourea leaching process of the concentrate.
Key words: sulphide concentrate; thiourea leaching; recovery of gold silver