METHOD OF PURIFYING ACIDIC SLIGHTLY MUDDY MINE AND UNDERDUMP WATER Russian patent published in 2010 - IPC C02F1/52 B01D21/01 C02F103/10 

FIELD: chemistry.

SUBSTANCE: invention relates to purification of slightly muddy waste water from suspended material and ions of heavy metals, for example mine and underdump water formed when extracting nonferrous metal ores through a mining or pit-run method. To realise the method, initial waste water containing ions of heavy metals is neutralised with lime milk to pH 7.0-8.5, treated with a polyacrylamide based flocculant, settled and clarified water is separated from the residue. The flocculant used is a mixture of anionic and cationic polyacrylamides with molecular weight not less than 10x10⁶ in volume ratio equal to 3-2:1. The flocculation process is carried out in the presence of a residue obtained after separating clarified water in the previous purification cycle. In the preferred version of the method, the residue obtained in the previous purification cycle is used in volume ratio to water coming in for purification equal to 0.5-1:10.

EFFECT: invention reduces consumption of flocculant by 3 times, increases density of the residue and reduces expenses on thickening the residue.

2 cl, 1 tbl, 13 ex