Process for producing phosphoric acid

摘要

The process for producing phosphoric acid provides for the decomposition of raw phosphate (rock phosphate) with sulphuric acid and phosphoric acid until a slurry is formed which contains the phosphoric acid and crystalline dihydrate or hemihydrate of the calcium sulphate, followed by the isolation of the end product from said slurry. According to the invention, the decomposition of raw phosphate is carried out with a mixture of sulphuric acid, phosphoric acid and part of the said slurry which is recycled to the decomposition stage, together with air in the form of a disperse system, the weight ratio of the disperse phase to the dispersant being from 1:0.09 to 1:0.16, or, to be fed in separately in the form of disperse systems, with a mixture of sulphuric acid and phosphoric acid with air, the weight ratio of the disperse phase to the dispersant being from 1:0.2 to 1:0.3, and said recycled slurry with air, its weight ratio being from 1:0.07 to 1:0.08, or with a mixture of sulphuric acid and phosphoric acid with air in the form of a disperse system, the weight ratio of the disperse phase to the dispersant being from 1:0.1 to 1:0.55.