METHOD FOR PRODUCTION OF EXTRACTION PHOSPHORIC ACID Russian patent published in 2009 - IPC C01B25/22 

FIELD: mining.

SUBSTANCE: invention is related to the field of production of extraction phosphoric acid (EPA) out of phosphor-containing raw materials with inclusion of low grade phosphate raw materials in process, in particular nodule phosphorites. Method for production of extraction phosphoric acid, includes phosphor-sulfuric acid decomposition of phosphate raw materials, containing apatite and nodule phosphoric concentrates, with creation of extraction pulp, its separation into phosphoric acid and residue of calcium sulfate by filtration, flushing of the latter with water and return of circulating phosphate solution produced after flushing into process. According to suggested method, nodule phosphoric concentrate is previously treated with circulating phosphate solution and/or extraction pulp taken in amount necessary for decomposition of carbonate part of nodule phosphoric concentrate, process of treatment is carried out at temperature of 60-90°C for 1-5 min, foam product is separated, and produced phosphate pulp is sent to the stage of phosphor-sulfuric acid decomposition. Ratio of apatite and nodule phosphorites is taken as equal to 1:(0.1-10). Process of phosphor-sulfuric acid decomposition is carried out either in dihydrate, or in semi-hydrate mode.

EFFECT: method makes it possible to produce acid of practically the same quality as from apatite, having preserved all parametres of process, and to avoid foam formation at the stage of decomposition.

4 cl, 1 tbl