Method for treating potassium chloride cyanide-free cadmium plating wastewater

A treatment method, potassium chloride technology, applied in metallurgical wastewater treatment, water/sewage treatment, chemical instruments and methods, etc., can solve problems such as inapplicability, and achieve the effect of simple and convenient treatment method

Active Publication Date: 2018-06-15
GUANGZHOU ULTRA UNION CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But this method is only suitable for the treatment of potassium chloride cyanide-free cadmium plating rinse water, which does not contain chromium ions, while the original wastewater discharge system and wastewater treatment equipment in the electroplating workshop of aerospace enterprises have been finalized, potassium chloride cyanide-free cadmium plating Wastewater often includes cadmium plating rinse water, cadmium plating passivation rinse water and deplating rinse water. In addition to containing cadmium ions, it also contains heavy metal ions such as chromium ions. This invention is not applicable to the existing potassium chloride cyanide-free plating Cadmium wastewater treatment equipment and cadmium plating wastewater

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Embodiment 1: a kind of processing method of potassium chloride cyanide-free cadmium plating rinse water

[0033] A. Reduction of hexavalent chromium: transfer potassium chloride cyanide-free cadmium plating rinsing water from the electroplating wastewater adjustment tank to the pH adjustment tank, stir the pool liquid, add dilute sulfuric acid solution to adjust the pH of potassium chloride cyanide-free cadmium plating rinsing water to 3.0, Add a 10% sodium metabisulfite aqueous solution with a mass concentration, use a potentiometer to control the ORP value of potassium chloride cyanide-free cadmium plating rinse water to be -250mV, and adjust the amount of 10% sodium metabisulfite aqueous solution;

[0034] B. Precipitation of heavy metal ions: the potassium chloride cyanide-free cadmium-plating rinse water after step A flows into the precipitation reaction tank, and under stirring conditions, every ton of potassium chloride cyanide-free cadmium-plating rinse water a...

Embodiment 2

[0039] Embodiment 2: a kind of processing method of chromic acid passivation rinse water of cadmium plating layer

[0040] The difference between embodiment 2 and embodiment 1 is that the processing object is the chromic acid passivation rinse water of the cadmium plating layer, and the remaining parameters and operations refer to embodiment 1.

[0041] The treatment results show that the contents of cadmium and chromium in the chromic acid passivation rinse water of the treated cadmium plating layer all meet the requirements in Table 3 of GB21900-2008 "Electroplating Pollutant Discharge Standard" (cadmium 0.01mg / L, chromium 0.5mg / L) .

Embodiment 3

[0042] Embodiment 3: A kind of treatment method of unqualified coating deplating rinsing water

[0043] The difference between embodiment 3 and embodiment 1 is that the processing object is unqualified coating deplating rinse water, and other parameters and operations refer to embodiment 1.

[0044] The treatment results show that the contents of cadmium and chromium in the deplating and rinsing water of unqualified coatings after treatment all meet the requirements in Table 3 of GB21900-2008 "Electroplating Pollutant Discharge Standard" (cadmium 0.01mg / L, chromium 0.5mg / L).

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PUM

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Abstract

The invention belongs to the field of wastewater treatment, and concretely to a method for treating potassium chloride cyanide-free cadmium plating wastewater. The method comprises the following steps: S1, adjusting the pH value of the wastewater, and adding an aqueous solution of sodium pyrosulfite; S2, adding an aqueous solution of sodium diethyldithiocarbamate, and adjusting the pH value of thewastewater; S3, adding a flocculant to make precipitated particles aggregate, and separating the precipitated particles from the wastewater; S4, adding hydrogen peroxide to the wastewater; and S5, adjusting the pH value of the wastewater treated in step S4. The method significantly reduces the content of cadmium and chromium in the potassium chloride cyanide-free cadmium plating wastewater to make the wastewater discharge meet the requirements of national standards, and is suitable for original wastewater treatment and discharge systems in existing electroplating workshops of enterprises.

Description

technical field [0001] The invention belongs to the field of waste water treatment, and in particular relates to a treatment method for potassium chloride cyanide-free cadmium plating waste water. Background technique [0002] Cadmium and its compounds are toxic to a certain extent. Long-term exposure or inhalation can lead to poisoning, which is harmful to human health and the environment. However, the standard electrode potential of cadmium is low, and it can be used as a sacrificial anode protective film for metals such as iron, aluminum or copper. It has low brittleness, good gloss and strong adhesion, so it is widely used in aerospace, navigation and electronic industry products, and cannot be replaced in the short term. The traditional cyanide cadmium plating solution and product quality are stable, but cyanide is one of the pollutants strictly prohibited by the state. Cyanide-free cadmium plating has gradually replaced cyanide cadmium plating. Because cyanide-free ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F101/20C02F101/22C02F103/16
CPCC02F1/56C02F1/62C02F1/66C02F1/70C02F1/722C02F9/00C02F2101/20C02F2101/22C02F2103/16
Inventor 郭崇武赖奂汶崔延昌
Owner GUANGZHOU ULTRA UNION CHEM LTD
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