METHOD OF PURIFYING WASTE WATER FROM PHOSPHATES Russian patent published in 2013 - IPC C02F1/58 C02F1/28 C01B25/36 B01J20/24 C02F101/10 

FIELD: chemistry.

SUBSTANCE: invention can be used to purify wastes from phosphates in chemical, metallurgical or petrochemical industry. The method is realised by treating water with aluminium sulphate to form insoluble aluminium phosphate particles and removing the solid treatment products from the treated water. Treatment is carried out in the presence of dispersed cellulose fibres in the water, said fibres containing at least 94 wt % fibres with length of not more than 1.23 mm and at least 54 wt % fibres with length of not more than 0.63 mm. The obtained solid treatment products in form of a composite material consist of said fibres with strongly sorbed chemically deposited aluminium phosphate particles. The composite material is removed by pressure floatation. In the preferred version, the fibres are dispersed in water in amount of 40-150 mg/dm³, wherein the composite material is removed from the treated water with aluminium phosphate content therein of 50-300 pts.wt per 100 pts.wt cellulose fibres, and a portion of the floatation sludge is returned to the treatment process.

EFFECT: method simplifies treatment by enabling treatment of water at a high volume rate equal to the rate of sludge formation, which cuts the duration of the treatment process.

4 cl, 4 ex