De. Akretche et al., SELECTIVE LEACHING OF A POLYMETALLIC COMPLEX ORE BY SULFURIC-ACID ANDTHIOUREA MIXED WITH SEA-WATER, Hydrometallurgy, 38(2), 1995, pp. 189-204
Leaching of a polymetallic complex ore from Oued El Kebir (Algeria) wa
s studied. This ore contains copper, lead, silver and zinc. In additio
n to the conventional roasting sulphuric acid leaching, the effect of
thiourea as leaching reagent was examined. In both cases all parameter
s were investigated and the increase in both lead and silver extractio
n by means of adding sea water was shown. Then, to improve the selecti
vity, leaching of this ore was carried out first at a 0.1 M concentrat
ion of sulphuric acid where both copper and zinc are dissolved. After
filtering, the dissolution of the acidified residue was followed using
a neutral solution of thiourea which contains 40% (vol/vol) of sea wa
ter. This second step allowed recovery of both silver and lead. The gr
ain size effect was also studied to optimise lead and silver dissoluti
on.