Method for electrolyzing and recovering hexavalent chrome in chromium-electroplating waste water

A technology of electrolytic recovery and electrochromium plating, which is applied in metallurgical wastewater treatment, chemical instruments and methods, water/sewage treatment, etc., can solve the problem that chromium cannot be reused, achieve low operating costs, low equipment investment, and good economic benefits Effect

Inactive Publication Date: 2009-10-07
吴秋波
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Problems solved by technology

[0004] The present invention aims at the disadvantage that the chromium recovered from the chrome wastewater cannot be reused in the electroplating tank existing in the treatment of the chromiu

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  • Method for electrolyzing and recovering hexavalent chrome in chromium-electroplating waste water

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Embodiment Construction

[0020] The present invention will be further described through the embodiments below with reference to the accompanying drawings.

[0021] Refer to attached figure 1 , a method for electrolytic recovery of hexavalent chromium in electrochrome plating wastewater, it comprises the following steps:

[0022] (1) Electrochrome plating waste water is injected in the reactor 4 through liquid inlet pipe 1, and sulfuric acid solution is added in electrochrome plating waste water under stirring, makes the pH value of electrochrome plating waste water be 1.0~1.3;

[0023] (2) Add sodium pyrosulfite to the chromium electroplating wastewater, the amount of sodium pyrosulfite added is 3.5 to 6 times that of hexavalent chromium, so that the oxidation-reduction potential of the electrochrome plating wastewater is below 220mv, and when the trivalent chromium salt begins to precipitate, then Add sodium carbonate solution to make the pH value of the chromium plating wastewater be 8.0 to 8.5;

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Abstract

The invention relates to a method for electrolyzing and recovering hexavalent chromium in chromium-electroplating waste water. Aiming at overcoming defects that chromium recovered from chromium waste water by the prior chromium-electroplating waste water treatment method cannot be reused for an electroplating tank, the invention provides the method for electrolyzing and recovering the hexavalent chromium in the chromium-electroplating waste water, which has simple operation and low recovering cost. The method comprises the following steps: sulfuric acid solution, sodium metabisulfite and sodium carbonate solution are sequentially added to the chromium-electroplating waste water; the reacted chromium-electroplating waste water flows into a precipitator for precipitation; through the precipitation, supernatant fluid flows into a neutralization pond for neutralization, the chromium-electroplating waste water is input a press filter for press filtering, and obtained chromic salts are washed with clear water; the chromium-electroplating waste water, the chromic salts and sulphuric acid are added in an electrolytic tank of a concentration purifier, and the sulphuric acid is added in a porous pot of the concentration purifier; when the concentration of the hexavalent chromium is larger than 20g/l and the concentration of trivalent chromium is smaller than 1g/l by electrolysis in the chromium-electroplating waste water in the electrolytic tank of the concentration purifier, the chromium-electroplating waste water can be used as a replenishing liquor for the electroplating chromium.

Description

technical field [0001] The invention belongs to the technical field of industrial waste water treatment, in particular to a method for electrolyzing and recovering hexavalent chromium from electrochrome plating waste water. Background technique [0002] So far, there are many ways to treat and recycle electroplating chromium wastewater, but basically it is recycled into trivalent chromium to make chromium oxide, ferrite, leather treatment agent, etc., and hexavalent chromium is also used to make chrome yellow, heavy Recycled sodium chromate, etc., have not been treated and reused in electrochrome plating tanks. The chromium wastewater in most existing electroplating plants is generally reduced to trivalent chromium salt, and then the wastewater flows into the comprehensive wastewater pool, where the trivalent chromium is turned into electroplating sludge and discarded. The electroplating sludge contains a variety of heavy metals , Such as copper, nickel, zinc, trivalent chr...

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Application Information

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IPC IPC(8): C02F9/06C02F1/461C02F1/62C02F1/66C02F103/16
Inventor 吴秋波
Owner 吴秋波
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