WILKOMIRSKY, I.; PARRA, R.; PARADA, F.; BALLADARES, E.:
Proceeding Copper 2013, Vol. IV, 302-314 (2013).
A new process is being developed which permit to recover up to 98% of copper, 76% molybdenum and 98% zinc from copper smelter slags, generating a solid residue of red hematite that can be used in paints and ceramics. The process consist of two consecutive step: an initial total sulphation of the slag at 150-180oC with sulphuric acid followed by a thermal decomposition at 700oC – 750oC of the sulphated slag to form copper and zinc sulphates, copper molybdate and hematite. The acid used in the first step of sulphation is re-synthtetical in the seconds step of thermal decomposition and recirculated back to the sulphation step. The process is being developed at pilot scale in a plant that will be commissioned by the end of 2013.