Hydrochloric acid process of producing feed level calcium diphosphate and gypsum coproduct

Abstract

The hydrochloric acid process of producing feed level calcium diphosphate and gypsum coproduct includes the steps of: acidolysis and depositing separation, filtering, the first section neutralization, the second section neutralization, preparing feed level calcium diphosphate, purification and concentrating calcium solution, synthesizing gypsum, recovering hydrochloric acid, and preparing gypsum product. The process adopts phosphate rock powder and sulfuric acid as main material, utilizes hydrochloric acid to acidolyze phosphate rock powder, recovers hydrochloric acid for reuse, controls the leaching out of fluorine and promotes it to precipitate for separating out, and has increased calcium solution purification step. The process has the features of high quality of feed level calcium diphosphate, P2O5 yield up to 90 %, production of gypsum with wide use, less environmental pollution and raised comprehensive utility.

Description

technical field [0001] The invention belongs to chemical production, and relates to a method for producing feed calcium hydrogen phosphate and co-producing gypsum by adopting a hydrochloric acid method. Background technique [0002] The production methods of conventional wet feed calcium hydrogen phosphate include sulfuric acid method and hydrochloric acid method, with the former being the main method. Although the sulfuric acid method has the characteristics of low production cost, easy access to the main raw material sulfuric acid, and large-scale industrial production; but there is defluorination and a large amount of phosphogypsum waste generated in the production (each ton of calcium feed product will produce 2.5 tons of phosphogypsum ) processing difficulty is big, and processing cost is high, and the gained calcium hydrogen phosphate causes the product phosphorus content on the low side because of containing a small amount of calcium sulfate, and can not utilize the d...