METHOD OF PURIFYING NATURAL WATER FROM IRON AND FLUORINE Russian patent published in 1996 - IPC

FIELD: water purification. SUBSTANCE: invention relates to a method in which water is treated with an aluminium sulfate/ferric sulfate mixture, clay, sodium hydrocarbonate, potassium permanganate, activated carbon, and starch followed by settling and filtration. In order to increase defluorination degree and reduce usage of reagents, the following makeup of blend is used (in wt %): aluminium sulfate, 15.4-19.0; ferric sulfate, 4.8-5.1; clay, 57.0- 61.6; sodium hydrocarbonate, 15.4-16.8; potassium permanganate, 0.95-1.0; activated carbon, 0.8-1.0; starch, the balance. Purification is carried out at pH 6.4-7.9. Another distinguishing feature consists in that the amount of blend corresponds to weight ratio of aluminium sulfate (recalculated for alumina) to fluorine equal to (7-9):1. EFFECT: enhanced efficiency of process.