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Treatment method of cadmium ion in EDTA-free acidic non-cyanide cadmium plating wastewater

A treatment method, cadmium ion technology, applied in metallurgical wastewater treatment, biological water/sewage treatment, neutralization water/sewage treatment, etc., can solve the problem that the treatment of acidic cyanide-free cadmium plating wastewater cannot meet the standard

Active Publication Date: 2017-01-18
GUANGZHOU ULTRA UNION CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] An object of the present invention is to provide a treatment plan for acidic cyanide-free cadmium-plating wastewater not containing EDTA, so as to solve the problem that the current treatment of acidic cyanide-free cadmium-plating wastewater cannot meet the standard

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Measured by titration, the mass concentration of cadmium ions in the NCC-617 plating solution is 18.2g / L. Use a pipette to draw 1mL of the plating solution into 6 100mL volumetric flasks, add 80mL of water and dilute with dilute sulfuric acid or hydrogen. Adjust the pH of the test solution with sodium oxide solution from 1.43 to 11.36, add water to 100 mL, and the cadmium ion in the obtained test solution is 0.182g / L. Investigations from the electroplating workshops of aerospace companies show that the mass concentration of cadmium in the cyanide-free cadmium plating wastewater is generally much lower than 0.182g / L. Treatment with the test solution can indicate the actual treatment of cyanide-free cadmium plating wastewater. Happening. Transfer the test solution in the volumetric flask into a 300mL beaker, add 2mL of 10% sodium dimethyldithiocarbamate (sodium thiram) solution to the test solution, stir the test solution for 20-30s, and use quantitative filter paper after...

Embodiment 2

[0030] Use a pipette to draw 1, 2, 3, 4, and 5 mL of NCC-617 acid cyanide-free cadmium plating solution into 5 100 mL volumetric flasks, and dilute to the mark with water. Transfer the test solution in the volumetric flask into a 300mL beaker, respectively add 10% sodium dimethyldithiocarbamate (sodium thiram) solution 2, 4, 6, 8, 10mL to the test solution in the above order, Stir the test solution for 20-30 seconds, filter the test solution with quantitative filter paper after 60 minutes, and measure the mass concentration of cadmium ion in the filtrate with a WFX-210 atomic absorption spectrophotometer. The results are listed in Table 2.

[0031] Table 2 The influence of the cadmium content in the test solution on the cadmium ion concentration in the filtrate after treatment

[0032] Cadmium in test solution (g / L)0.1820.3640.7281.5462.912 Add thiram (g / L)2.0484.0968.19216.34832.768 PH of test solution6.736.616.546.486.39 Cadmium in the filtrate (mg / L) 0.0050.0180.0370.0930...

Embodiment 3

[0035] Major equipment:

[0036] Acidic cyanide-free cadmium plating wastewater storage tank;

[0037] pH adjustment pool;

[0038] Precipitation reaction tank;

[0039] Flocculation tank

[0040] Inclined pipe settlement tank;

[0041] Neutralization reaction tank;

[0042] Biochemical reaction tank

[0043] Plate and frame filter press.

[0044] Chemicals:

[0045] Precipitating agent: 10% sodium dimethyldithiocarbamate aqueous solution;

[0046] Flocculant: 0.5% aqueous polyacrylamide solution;

[0047] Dilute sulfuric acid: the volume ratio of concentrated sulfuric acid to water is 1:9;

[0048] Sodium hydroxide solution: the mass fraction is 5% sodium hydroxide aqueous solution.

[0049] Step 1: Adjust the pH of the wastewater: pump the electroplating wastewater from the NCC-617 acidic cyanide-free cadmium plating wastewater storage tank into the pH adjustment tank, stir the tank liquid, add dilute sulfuric acid or sodium hydroxide solution to adjust the wastewater pH = 4.43 ~ 6.73, use Th...

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PUM

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Abstract

The invention discloses a treatment method of cadmium ion in acidic non-cyanide cadmium plating wastewater containing no strong coordination agent EDTA. When pH of cadmium plating wastewater is 2.47-9.34, sodium dimethyldithiocarbamate and cadmium ion react to generate cadmium dimethyl dithiocarbamate precipitate; after the precipitate is separated, content of cadmium ion in discharged wastewater meets requirements of GB 21900-2008 ''electroplating pollutant discharge standard'' Table 2. When pH of the wastewater is 4.43-6.73, sodium dimethyldithiocarbamate precipitate cadmium, cadmium ion in the wastewater meets requirements of GB 21900-2008 ''electroplating pollutant discharge standard'' Table 2.

Description

Technical field [0001] The invention relates to the field of wastewater treatment, in particular to a method for treating cadmium ions in acidic cyanide-free cadmium plating wastewater without EDTA. Background technique [0002] The cadmium plating layer has excellent corrosion resistance and flexibility, and has been widely used. Cadmium and its compounds have certain toxicity. At the end of the 20th century, the cadmium plating process has been basically eliminated from the electroplating of civilian products. However, due to the special requirements of aerospace, navigation and some electronic products, some companies still retain a certain amount of cadmium plating process. . The quality of traditional cyanide cadmium plating solutions and products is stable, but cyanide is one of the pollutants strictly prohibited by the state. It is imperative to replace cyanide cadmium plating with cyanide-free cadmium plating, and time is pressing. In accordance with the requirements of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/14C02F101/20C02F103/16
CPCC02F1/54C02F1/66C02F3/00C02F9/00C02F2001/007C02F2101/20C02F2103/16
Inventor 郭崇武赖奂汶
Owner GUANGZHOU ULTRA UNION CHEM LTD
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