METHOD FOR PREPARING AMMONIUM PHOSPHATE Russian patent published in 2004 - IPC

FIELD: inorganic chemistry, chemical technology, fertilizers. SUBSTANCE: invention relates to methods for preparing ammonium phosphates, namely ammophos and diammonium phosphate, based on the decomposition of ammonium raw with a mixture of phosphoric and sulfuric acids to obtain phosphoric acid and its the following process for fertilizers. Such fertilizers are used in agriculture widely. Method involves decomposition of apatite concentrate with mixture of sulfuric and phosphoric acids, separation of prepared pulp by filtration and isolation of production phosphoric acid, washing out calcium sulfate precipitate with water, recovery washing out waters to decomposition stage, ammonization of acid, granulation and drying product. By this method filtrate obtained after separation of pulp is fed to clearing up to the residual content of solid substances in production phosphoric acid 0.2-0.5 % by mass and fed to ammonization stage. Condensed pulp containing 10-35% of solid substances is recovered to decomposition stage completely. The following variants in carrying out the method are possible: before feeding to ammonization a cleared acid is concentrated partially or completely up to the necessary concentration. Invention provides preparing ready product showing stability of export quality in minimal consumptions for manufacturing and also new products containing nutrient substance by 1-5% more in reducing exploitation consumptions and specific amount of metal per structure. EFFECT: improved preparing method. 3 cl, 4 ex