PRODUCTION OF PHOSPHATE COMPOUNDS OF MATERIALS CONTAINING PHOSPHORUS AND AT LEAST ONE METAL SELECTED FROM IRON AND ALUMINUM Russian patent published in 2022 - IPC C02F11/00 C01B25/22 C01B25/26 C05B11/04 C05B11/16 C05F7/00 

FIELD: chemistry.

SUBSTANCE: invention relates to the processing of materials containing phosphorus and at least one metal selected from iron and aluminum, and in particular to the processing aimed at reuse. A method for producing phosphate compounds includes dissolving raw materials containing ash of sewage sludge containing phosphorus, aluminum and iron in hydrochloric acid. Insoluble residues from the dissolution stage are separated. Iron hydroxide is added, causing precipitation of phosphate compounds. Precipitated phosphate compounds are removed. Phosphate compounds are dissolved with an alkaline solution. Iron hydroxide is filtered out. Lime is added, causing precipitation of calcium phosphate. Precipitated calcium phosphate is separated. A leaching solution, after separation of precipitated calcium phosphate, is reused to dissolve phosphate compounds with an alkaline solution. Phosphorus is isolated in a valuable form that does not contain heavy metals from any type of ash of sewage sludge. In addition, the isolation of other elements contained in ash, such as calcium, iron, aluminum, heavy metals, etc., is ensured.

EFFECT: obtaining phosphate compounds.

8 cl, 39 dwg, 19 tbl