METHOD OF PRODUCING WET-PROCESS PHOSPHORIC ACID FROM KARATAU PHOSPHORITE TYPE RAW MATERIAL Russian patent published in 2011 - IPC C01B25/225 

FIELD: chemistry.

SUBSTANCE: invention relates to dihydrate methods of producing wet-process phosphoric acid, which is used to produce mineral fertiliser, from Karatau phosphorite type raw material. Phosphate material is decomposed with sulphuric acid and recycled phosphoric acid at temperature 70-75°C. The decomposition product, which is separated by filtration from a calcium sulphate residue with P₂O₅ content of 19-22%, is evaporated to P₂O₅ content of not less than 35% and settled. The decomposition product, which is separated by filtration from the calcium sulphate residue with P₂O₅ content of 19-22%, is evaporated to P₂O₅ content of 41-45% and then mixed with the decomposition product, which is separated by filtration from the calcium sulphate residue with P₂O₅ content of 19-22%, to bring P₂O₅ content in the obtained wet-process phosphoric acid to 35-40%. The difference in densities of the wet-process phosphoric acid with P₂O₅ content 41-45% and wet-process phosphoric acid with P₂O₅ content 35-40% is kept in the range of 0.08-0.14 g/cm³.

EFFECT: method has high efficiency on the coefficient of extraction of P₂O₅ into the solution, coefficient of washing off phosphogypsum and content of P₂O₅ in the obtained wet-process phosphoric acid, while reducing power consumption and corrosiveness of the decomposition process.

4 cl, 1 tbl, 1 dwg, 2 ex