Ks. Rao et Rk. Paramguru, DISSOLUTION OF SPHALERITE (ZNS) IN ACIDIC FERRIC SULFATE-SOLUTION IN THE PRESENCE OF MANGANESE-DIOXIDE, Minerals & metallurgical processing, 15(1), 1998, pp. 29-34
Citations number
12
Categorie Soggetti
Metallurgy & Metallurigical Engineering","Mining & Mineral Processing
This paper describes a new approach for examining the kinetics and mec
hanism of zinc dissolution from sphalerite concentrate in acidic ferri
c sulfate solution in the presence of manganese dioxide. A literature
search was performed to access the possible action of the two oxidizin
g agents, i.e., ferric ion and manganese dioxide. The possibility of g
alvanic coupling between ZnS and MnO2 and the cyclic action of the red
ox couple, Fe2+/Fe3+, on these two minerals were theoretically examine
d based on corrosion principles. Expressions for the mixed potential (
E-m,) and the mixed current (i(m)), were derived for the relevant corr
osion and galvanic couples. Leaching experiments were conducted to est
ablish which of the above phenomena is operative during leaching. The
results indicated that the dissolution mostly occurs by the action of
ferric ion on ZnS producing ferrous ions. The presence of MnO2 enables
a quick conversion of ferrous to ferric, which maintains the rate of
Zn dissolution. The process has promising features for commercial expl
oitation.