SU1747394A1 - Method for purification sulfide containing sewage - Google Patents

Abstract

Use: wastewater treatment of flotation processing plants processing copper and copper-molybdenum ores. SUMMARY OF THE INVENTION: Wastewater is treated with a stoichiometric amount of copper-containing reagent at 70-80 ° C. 1 tab.

Description

The invention relates to wastewater treatment of non-ferrous metallurgy enterprises and can be mainly used for wastewater treatment of flotation concentration plants processing copper or copper-molybdenum ores, where large amounts of sodium sulfide are used as a flotation reagent.

Closest to the proposed method is the removal of soluble sulphide from washing wastewater. In accordance with this method, soluble sulphides are removed from wastewater by adding various acidic liquid wastes containing sufficient amount of soluble metal ions, such as zinc, copper, iron, to the treated streams. for complete precipitation of sulfides as insoluble metal sulfides. Moreover, the purification is carried out in two stages: copper-containing acidic wastes are first added and up to 90% (not more) of copper sulfide sulphides are precipitated, and then another acidic waste containing iron is added to purify the remaining sulfide ions as iron sulfide. .

The disadvantage of this method is the stepwise implementation, which during the purification of large volumes of wastewater makes it very difficult to filter individual sediments. This method does not allow simultaneous purification of thiosulphate solutions, which are always present in sulphide-containing solutions as a product of the natural decomposition of sodium sulfide.

The aim of the invention is to simplify the process while simultaneously purifying from thiosulfates.

The goal is achieved by the fact that according to the proposed method, which includes treating with copper-containing reagent and separating sludge, wastewater is treated with a stoichiometric amount of precipitating reagent at 70-80 ° C.

To carry out the process, the initial wastewater containing sulphides, hydrosulphides and thiosulphates is introduced, calculated by stoichiometry to the amount of sulphide and thiosulphate ions, the required amount of copper vitriol copper chloride or acidic copper-containing effluents of copper plants. min at 70-80 ° C

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Depending on the need for further discharge or use of the liquid phase, the pulp or the filtrate is alkalinized to neutrality from the balance. After filtration of the copper sulfide precipitate in the filtrate, there are no sulfide and thiosulfate ions either.

The introduction of a precipitating reagent in an amount less than the stoichiometrically necessary, and the treatment at lower temperatures does not achieve the goal: the COD of the treated effluent remains high due to the presence of thiosulfate ions in them. Aftertreatment causes an unjustified complication of the process, an increase in the cost and time required for the complete purification of impurities remaining in the solution,

Example K1p of an artificially prepared solution containing 2.2 g / l of sulfide ion, 5.06 g / l of thiosulfate ion, is added with stirring the stoichiometric amount (28.4 g) of copper vitriol. Part of the pulp is filtered without heating (at room temperature), and the rest is heated to a certain temperature with intermediate filtration and determination of the residual content of sulfide and thiosulfate ions.

The results of the deposition of sulfide and thiosulfate ions at different temperatures are shown in the table.

Example 2. K1l plum thickener copper concentrate with a pH of 11.5 composition, g / l: sulfide ions of 1.6; thiosulfate 3.1; sulfite ions 0.15; COD (dichromate) - 4400 mg / l 02

with stirring, 19 g of copper sulfate CuSCM SHaO are added. The pulp is heated to 70 ° C for 30 minutes, alkalized with lime to pH 8, the precipitate is separated by filtration. Sulfide-, thiosulfate-, sulfite ions are absent in the filtrate, COD

purified solution of 25.0 mg / l 02. Weight

sediment 7.5 g, the copper content in it is 64.1%.

Simultaneously with the cleaning solution from

sulfide-, hydrosulfide-, sulfite- and thiosulfate-ions the proposed method allows for 60-70% purification of these solutions from oils and petroleum products. The initial solution contained 30 mg / l of substances extracted by ether. After cleaning them

content decreased to 10.5 mg / l. This greatly simplifies the cleaning process.

The precipitates of copper sulphides in the form of copper-rich concentrate go to the metallurgical processing, the purified effluents go to the circulating water supply system.

Claims (1)

Invention Formula The method of purification of sulphide-containing wastewater by treatment with copper-containing reagent with the separation of the resulting sediment is distinguished by the use of the reagent at 70-80 ° C to simplify the process while cleaning from thiosulphates.