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Treatment method of potassium chloride cyanide-free cadmium plating and passivation mixed wastewater

A technology of mixed wastewater and treatment method, which is applied in the fields of metallurgical wastewater treatment, chemical instruments and methods, oxidized water/sewage treatment, etc., can solve problems such as inability to effectively destroy ammonium triacetic acid, inability to meet COD, and achieve low treatment costs and reduced costs. Effect of COD Value

Active Publication Date: 2022-02-01
GUANGZHOU ULTRA UNION CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this technical scheme, hydrogen peroxide is used to oxidize organic matter in wastewater, but hydrogen peroxide cannot effectively destroy complexing agents such as nitrilotriacetic acid, and COD after wastewater treatment generally cannot meet the requirements of the GB 21900-2008 standard

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Embodiment 1: process cadmium-containing 150mg / L potassium chloride cyanide-free cadmium plating and passivation mixed waste water

[0051] This embodiment provides a kind of processing method of potassium chloride cyanide-free cadmium plating and passivation mixed wastewater, to process potassium chloride cyanide-free cadmium plating and passivation mixed wastewater containing cadmium 150mg / L, potassium chloride cyanide-free cadmium plating and passivation mixed wastewater containing 150mg / L of cadmium ions, 1500mg / L of carboxyl-containing complexing agents such as nitrilotriacetic acid, 50mg / L of trivalent chromium, and 50mg / L of hexavalent chromium; including the following steps:

[0052] Step 1. Precipitate cadmium ions

[0053] Transport the waste water from the potassium chloride cyanide-free cadmium plating and passivation mixed waste water adjustment tank to the cadmium sedimentation tank, add lime emulsion to adjust the pH of the waste water to 6-7, and add 20L...

Embodiment 2

[0066] Embodiment 2: process cadmium-containing 300mg / L potassium chloride cyanide-free cadmium plating and passivation mixed wastewater

[0067] The present embodiment provides a kind of processing method of potassium chloride cyanide-free cadmium plating and passivation mixed wastewater, to process cadmium-containing 300mg / L potassium chloride cyanide-free cadmium plating and passivation mixed wastewater, potassium chloride cyanide-free cadmium plating and The passivation mixed wastewater contains 300 mg / L of cadmium ions, 3000 mg / L of carboxyl-containing organic acid complexing agents such as nitrilotriacetic acid, 50 mg / L of trivalent chromium, and 100 mg / L of hexavalent chromium; including the following steps:

[0068] Step 1. Precipitate cadmium ions

[0069] The waste water is input into the cadmium sedimentation tank from the potassium chloride cyanide-free cadmium plating and passivation mixed waste water adjustment tank, and the lime emulsion is added to adjust the p...

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Abstract

The invention provides a treatment method for potassium chloride cyanide-free cadmium plating and passivation mixed wastewater, using the precipitating agent sodium dimethyldithiocarbamate to precipitate cadmium, and adjusting the pH with lime emulsion, through dimethyldithiocarbamate The synergistic effect of sodium carbamate and calcium ions is to use calcium ions to precipitate carboxyl-containing organic acid complexing agents such as nitrilotriacetic acid in wastewater under alkaline conditions. After the complexing agents in wastewater are precipitated, they are released from complex ions Trivalent chromium reacts with sodium dimethyl dithiocarbamate to form precipitates, thereby effectively removing trivalent chromium, and using ferrous ions to reduce hexavalent chromium to trivalent chromium and form precipitates under the condition of pH 10-12 , can effectively remove hexavalent chromium in wastewater, and remove the remaining sodium dimethyl dithiocarbamate in wastewater by precipitation, which greatly reduces the COD value of wastewater. The method has simple process, low processing cost and good market application prospect.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, and in particular relates to a treatment method for potassium chloride-free cadmium plating and passivation mixed wastewater. Background technique [0002] Cyanide cadmium plating is a commonly used cadmium plating method, but cyanide is very toxic, and there is a big safety hazard in the discharge of wastewater after treatment. In order to eliminate cyanide cadmium plating, Guangzhou Chaobang Chemical Co., Ltd. developed a potassium chloride cyanide-free cadmium plating process, which has been widely used in Guizhou aerospace enterprises and achieved good environmental and social benefits. [0003] After cadmium plating, aerospace parts are treated with hexavalent chromium passivation. The cadmium plating wastewater and passivation wastewater from the traditional cadmium plating production line flow into the cadmium plating wastewater regulating tank together, and then ar...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C02F101/22C02F103/16
CPCC02F1/76C02F1/5245C02F1/56C02F2103/16C02F2101/22
Inventor 郭崇武李小花赖奂汶
Owner GUANGZHOU ULTRA UNION CHEM LTD