PROCESS FOR THE PRODUCTION OF NICKEL, HIGH-PURITY MAGNESIUM OXIDE AND CEMENT

摘要

Sulfuric acid leaching is applied to recover nickel from a nickel-containing oxidic raw material which also contains magnesium and iron. High-purity magnesium oxide and cement are produced at the same time. The heavy metals are separated by an organic metal extraction agent; nickel, cobalt and manganese are stripped therefrom by a mineral acid, and the nickel is recovered. Copper, zinc and iron are obtained by further stripping with sulphuric acid. Carbon dioxide and ammonia are added to the aqueous solution obtained from the heavy metal separation stage to precipitate magnesium carbonate or hydroxide carbonate and an ammonium sulphate solution is formed. The precipitation product is separated and calcined to form magnesium oxide. Gypsum is formed from the ammonium sulphate solution and is fired to form cement clinker. The resulting sulphur dioxide containing gas is processed in a sulphuric acid plant and used in the raw material leaching stage.