METHOD OF PHOSPHORUS RECOVERY Russian patent published in 2009 - IPC C22B7/00 C01B25/02 C22B3/22 

FIELD: chemistry.

SUBSTANCE: invention refers to method of phosphorus recovery from aqueous slurry to be divided into aqueous suspension containing suspended phosphorus particles and impurities, and coarse solid particles. Adding flocculant to the suspension enables to agglomerate suspended phosphorus particles and impurities removed from water and heated up to melt element phosphorus. Coalescing agent is added to coalesce melted element phosphorus separated from impurity particles. Coarse solid particles are mixed with hot water to melt phosphoric sludge thereafter separated from inert solid particles. Solid particles are heated up to burn any residual element phosphorus. Separated melted phosphoric sludge is mixed with chromic acid solution to recover phosphorus as a separate phase. Reducing agent is added to residual water and solid particles thus reducing Cr⁺⁶ in Cr⁺³. At last, alkali is added to water and solid particles to ensure reaction with residual phosphorus and produce phosphorus compounds. Reaction mass is filtered. Filter cake is to be buried as a safe waste.

EFFECT: transformation of residual processing sludge into safe waste.

9 cl, 1 dwg, 1 ex