METHOD OF PREPARING ALUMINA FROM HIGH-SULFUR AND HIGH- CARBONATE BAUXITE Russian patent published in 2000 - IPC

FIELD: chemical industry, more particularly processing of bauxite with high carbonate and sulfur content using Bayer sintering process. SUBSTANCE: method comprises crushing, grinding, classifying the pulp and the latter is further processed to isolate alumina. Grinding is carried out in the presence of circulating alkali solution. Sand fraction resulting from classification is further ground to particle size of 2 mm with yield of 2+1 mm class being not higher than 15%, and leached out. Sand fraction containing iron sulfide and carbonate is isolated from leaching pulp and is dumped, and leaching pulp is further processed. Invention makes it possible to simplify the process and increase amount of stock for preparing alumina to 85%. EFFECT: more efficient preparation method. 3 tbl