PROCESS FOR THE REFINEMENT OF RESIDUES FORMED IN ELECTROLYTIC ZINC PROCESSES AND CONTAINING BASIC SULPHATES AND HYDROXIDE OF IRON, AND ZINC FERRITE, AND FOR THE RECOVERY OF THE ZINC PRESENT IN THE RESIDUES

摘要

Purification of residues from zinc extraction contng. basic sulphates, hydroxides, Fe and Zn ferrite comprises thermally treating the alkaline suspension so that the partial pressure of O and S and the temp. of the system Zn-Fe-So w.r.t. ZnSO4 and Fe2O3 stability are controlled, the zinc and other non ferrous metals pass into soluble sulphates the hydroxide and ferrite being transformed into oxides leaving the non-oxide as the only insoluble component permitting this to be filtered off. Avoids scrapping of high tonnages of Fe2O3 because of their high Zn content.