METHOD OF PREPARING COAGULATION-FLOCCULATION REAGENT AND WATER TREATMENT PROCESS Russian patent published in 1999 - IPC

FIELD: water treatment. SUBSTANCE: invention relates to inorganic substance technology and can be of use to prepare iron- containing coagulant-flocculants for treating water, precipitating mineral dispersed materials from aqueous suspensions, and for concentrating metals dissolved therein. Coagulation-flocculation reagent is prepared by treating iron-silicon material with 5-25% sulfuric or hydrochloric acid with its 60-100% intake as compared to stoichiometrically required amount to provide molar ratio of total iron to oxygen from 1:0.2 to 1:1.7. As iron-silicon materials, concentration- plant waste and metallurgical production reject slags containing fayalite and/or olivine are utilized; and so are, as acid solution, acidic etching solutions from metallurgical enterprises or wash sulfuric acid from sulfuric acid production, or gaseous hydrogen chloride from caustic soda production are utilized. Water is treated by adding reagent containing iron salt and colloidal silicic acid while controlling pH of liquid phase of suspension formed within a range of 3.5-11.0, after which suspension is settled and liquid phase separated from precipitate. EFFECT: increased reagent's immunity to polymerize and reduced content of ballast components; increased degree of water purification owing to extended treatment pH range. 4 cl