S. Prasad et al., SULFATION OF CHALCOPYRITE WITH STEAM AND OXYGEN IN THE PRESENCE OF SOME ADDITIVES, Materials transactions, JIM, 37(6), 1996, pp. 1304-1310
It has been observed that the sulphides undergo weathering process to
produce the metal sulphates at a very slow rate. Therefore, higher con
version to sulphates may be achieved by creating aggressive conditions
at higher temperature similar to that of weathering process by using
a mixture of steam and oxygen. The results obtained by this method sho
ws a conversion of 82.32% copper sulphate from a chalcopyrite concentr
ate at 773 K in presence of 10% Fe2O3. The role of different additives
like ferric oxide, ferrous sulphate and sodium sulphate on sulphation
of chalcopyrite with steam and oxygen was investigated. The copper su
lphate formation without any additive was found to be 71.9% whereas th
e values were 84.4 and 86.5% with 10% Na2SO4 and 20% FeSO4 respectivel
y at 773 K. The kinetics of the sulphation with additives has also bee
n studied in the fixed bed in the temperature range 673-773 K in absen
ce of external mass transfer effect due to particle size, how rate, et
c. The reaction was found to be topochemical in nature. The activation
energy values using the Arrhenius equation plots were obtained as 29.
2 kJ/mol with 10% Fe2O3, 23.57 kJ/mol with 10% Na2SO4 and 21.03 kJ/mol
with 20% FeSO4 in the above temperature range. The sulphated products
were characterized by XRD and SEM studies.