RECOVERY OF METAL OXIDES AND ASSOCIATED ACID FROM PROCESS SOLUTIONS USING WATER AS REAGENT

摘要

Traditionally, metal oxides have been recovered from chloride-based liquors by either precipitation of the hydroxide or carbonate, followed by calcining, or by direct pyrohydrolysis of the chloride salt. In this paper, an alternative method of recovering metal oxides, and simultaneously recovering the hydrochloric acid for recycle, from chloride solutions is presented. The use is made of the unique properties of concentrated chloride solutions to hydrolyse and precipitate either the metal oxide directly, or the basic chloride which can then be calcined to the pure oxide. Results are presented for the recovery of copper, cobalt and nickel as basic chlorides, and iron as hematite. The application of this technique as applied to copper is also demonstrated in nitrate media.