METHOD FOR PROCESSING LATERITE ORES UNDER PRESSURE AT HIGH TEMPERATURE FOR THE SELECTIVE DISSOLUTION OF NICKEL AND COBALT

摘要

The present invention concerns a method for the selective dissolution of nickel and cobalt from laterite ores with the assistance of (a) sulphadisation and (b) oxidative extraction at elevated temperature and pressure. Sulphadisation of the ore takes place in conditions of elevated pressure and temperature in an inert atmosphere. This processing precedes the oxidative extraction during which the nickel and cobalt are selectively dissolved from the nickel-containing laterite, while the dissolution of the iron in the extraction solution is minimised. The stage of sulphadisation of the laterite ore is the main point of the invention and contributes to the increased dissolution of the nickel and cobalt to a significant percentage. The main point of this invention is the sulphadisation of the laterite ore and the subsequent production of a solution of sulphuric acid in situ in sufficient quantity to dissolve the nickel and cobalt contained in the ore.