Utilizing Iron Residues from Zinc Production in the U.S.S.R.

When zinc calcine leach residues are subjected to conventional hydro-metallurgical treatment, iron is removed from the production circuit in the form of jarosite or goethite. A combined hydrometallurgical treatment of zinc calcine and zinc oxide fume leach residues applied at a zinc plant in the U.S.S.R. produces potassium jarosite containing undesirable impurities of 1.5–2.0 wt.% Zn, 0.2–0.3 wt.% Cu, 0.2–0.6 wt.% Pb, 0.005–0.01 wt. % Cd and 27–29 wt. % Fe. After some study, it was found that low-contaminant jarosite can be used in iron-oxide pigments and in cement clinker production. Methods for manufacturing such products have been developed and tested on a pilot-plant scale, and commercial tests are in progress. The investigations carried out for low-contaminantjarosite utilization resulted not only in the development of a wasteless and environmentally acceptable technology for zinc calcine treatment, but made it possible to recover one more valuable component—iron—from zinc raw materials.