RU94026839A - Process for purification of alkalized waste water, inorganic coagulator for waste water purification, and method of preparation thereof - Google Patents

Abstract

FIELD: production of inorganic substances. SUBSTANCE: alkalized waste water is purified with assistance of inorganic coagulator on the basis of aluminium and iron taken in amount 0.07- 2.5 g/l followed by agitation and settling. Coagulator containing 2-10 wt % alumina, 2-10 wt % ferric oxide, and 2-10 wt % sulfuric acid (including 20-40% of free acid) in water may be prepared from red slime formed in silica production. The latter is first treated with 3-5% hydrochloric acid observing 1:(5-10) solids to liquid ratio, whereupon solid residue is treated with 50-55% sulfuric acid at 100-110 C and 1:(6-8) solids to liquid ratio, pulp is filtered, and to solution obtained, concentrated sulfuric acid is added, its total concentration in solution having thereby reached 20-50 wt %. The solution is then allowed to stand for 1-20 h and settled down precipitate is separated. Method and coagulator make it possible not only to clarify waste water but also to considerably reduce its alkali content. So method may find use at water-purification stations, in particular at those for clarification and neutralization of wastes from metallurgical, enrichment, and chemical enterprises. EFFECT: increased degree of waste water purification.

Claims (1)

The invention relates to a technology for the production of inorganic substances and the processing of mineral raw materials and can be used at enterprises of alumina production and processing plants to obtain additional marketable product from waste. The invention also relates to a technology for treating wastewater having a high alkali content, and can be used in wastewater treatment plants, in particular stations for clarification and neutralization of industrial wastewater from metallurgical, enrichment and chemical industries. A method for purifying alkalized wastewater by introducing an inorganic coagulant based on aluminum and iron in an amount of 0.07 - 2.5 g / l, followed by stirring and settling. The inorganic coagulant used in the purification method contains components in the following ratio, wt.%: Al ₂ O ₃ 2 - 10; Fe ₂ O ₃ 2 - 10; H ₂ SO _{4 total} 40 - 60 (including H ₂ SO _{4 free} 20 - 40); H ₂ O _cristo - up to 100. The proposed coagulant can be obtained from red mud of alumina production, which is first treated with 3 - 5% hydrochloric acid with a ratio of t: w = 1: 5 - 10, and then the solid residue is treated with 50 - 55 % sulfuric acid at a temperature of 100 - 110 ^o C and a ratio of t: W = 1: 6 - 8, the pulp is filtered, and concentrated sulfuric acid is added to the resulting solution until its total content in the solution is 25 - 50 wt.%, solution incubated for 10-20 hours and the precipitate is separated. The proposed method of wastewater treatment and the coagulant used in this method allows not only to clarify the effect, but also significantly reduce the alkali content in wastewater.