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Hexavalent chromium-containing waste water treatment method

A technology for wastewater treatment and hexavalent chromium, which is applied in water/sewage multi-stage treatment, neutralized water/sewage treatment, reduced water/sewage treatment, etc. The problem of large dosage of solid ferrous sulfate, etc., achieves the effect of less slag and convenient treatment

Inactive Publication Date: 2011-05-25
AVIC STANDARD PARTS MFG
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  • Description
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Problems solved by technology

[0013] The purpose of the present invention is mainly to provide a new wastewater treatment method containing hexavalent chromium in order to solve the above problems existing in the existing chromium-containing wastewater treatment method. Large amount of solid ferric hydroxide precipitates; when treating hexavalent chromium wastewater, the amount of lime added is large, resulting in many solid chromium hydroxide precipitates, etc.

Method used

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  • Hexavalent chromium-containing waste water treatment method
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  • Hexavalent chromium-containing waste water treatment method

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Embodiment 1

[0036] Embodiment 1: Chromium-containing wastewater treatment method is:

[0037] ①Add industrial sulfuric acid with ρ=1.84mg / mL in the reaction tank, according to the calculation formula G 1 =D×Q Calculate the acid dose and add it carefully and slowly;

[0038] where: G 1 : Acid dose, kg

[0039] D: per m 3 The amount of acid required for wastewater is 0.3 ~ 0.4kg / m 3

[0040] Q: Total volume of wastewater

[0041] 2. Add sodium metabisulfite in the reaction tank, and add it according to the weight ratio of sodium metabisulfite to hexavalent chromium ion at a dosage ratio of 3.5:1, so that the hexavalent chromium in the chromium-containing wastewater is reduced to trivalent chromium;

[0042] ③ Add sodium hydroxide to the neutralization tank to make the trivalent chromium completely form chromium hydroxide precipitation, and add sodium hydroxide according to the following formula:

[0043] G2=T×Q

[0044] In the formula: G2: the mass of caustic soda to...

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Abstract

The invention discloses a hexavalent chromium-containing waste water treatment method, which uses sodium hydrogensulfite generated by hydrolysis of sodium pyrosulfite as a reducer and adopts an intermittent process technique for treatment. The concrete treatment process comprises: 1, adding sulfuric acid into waste water, and regulating the pH value of the waste water to 2.0 to 3.0; 2, adding sodium pyrosulfite to reduce hexavalent chromium in the waste water into trivalent chromium, wherein the adding ratio of the sodium pyrosulfite is calculated according to the weight ratio of sodium pyrosulfite to hexavalent chromium of 3.5-5:1; 3, adding sodium hydroxide into a neutralization tank to regulate the pH value of the waste water to 8 to 9 to precipitate the trivalent chromium completely in form of chromium hydroxide; and 4, separating a solid phase from a liquid phase by using the flocculation force of a polyacrylamide polymeric flocculant and the action of a tube sedimentation tank, discharging waste water, piling mud in a centralized manner after press-filtering the mud by a press filter, and processing the mud uniformly according to regulations.

Description

technical field [0001] The invention relates to a method for treating wastewater by chemical methods, in particular to a method for treating wastewater containing hexavalent chromium by chemical methods. Background technique [0002] At present, the surface treatment of electrochromic electroplating, electropolishing, chemical oxidation of aluminum parts, pickling of copper parts, passivation of copper parts, light emission after electroplating and high chromium passivation, light emission after electroplating cadmium and high chromium passivation, and white color after electroplating After passivation, black passivation, and dichromate filling, the cleaning wastewater contains highly toxic hexavalent chromium, which flows into the wastewater treatment tank through the sewage pipe. The PH value of these chromium-containing wastewater is generally between 3 and 6, and its main components are chromic anhydride, sulfuric acid and nitric acid, and the ions contain Cr +6 , Fe +...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F1/66C02F1/70C02F101/22
Inventor 陈红英
Owner AVIC STANDARD PARTS MFG
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