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Processing method of electroplating wastewater containing cyanogens and chrome

A treatment method and a chromium electroplating technology are applied in the field of treatment of cyanide-containing chromium-containing electroplating wastewater, which can solve the problems of unpublished concentrated water treatment methods, unsuitability for treatment, and high energy consumption, achieve significant energy-saving effects, and simplify the concentrated water treatment process. , the effect of reducing processing costs

Inactive Publication Date: 2012-07-04
NANJING NORMAL UNIVERSITY
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  • Claims
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Problems solved by technology

[0003] Chinese patent CN100413791C discloses an electroplating wastewater integrated membrane separation and recycling process, CN101481157A discloses an integrated membrane advanced treatment electroplating wastewater process, and CN1590322A discloses a membrane separation method for zero discharge of electroplating wastewater treatment, these methods are for single electroplating Variety of rinsing water treatment, not suitable for treatment of mixed electroplating wastewater containing cyanide and chromium
[0005] Chinese patent CN101318732B discloses a process of recycling electroplating wastewater to produce pure water. The electroplating wastewater containing heavy metal ions is sequentially subjected to pretreatment, nanofiltration and reverse osmosis separation to obtain pure water for production. Although the water quality of this process is good, the investment Large, high energy consumption, unpublished concentrated water treatment method

Method used

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  • Processing method of electroplating wastewater containing cyanogens and chrome
  • Processing method of electroplating wastewater containing cyanogens and chrome

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Experimental program
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Effect test

Embodiment 1

[0026] A mixed electroplating wastewater containing cyanide and chromium, the pH value is 7.5, the total cyanide content is 21.8mg / L, the hexavalent chromium content is 27.5mg / L, and the total heavy metal ion content such as copper and zinc is less than 100mg / L. use as figure 1 The method shown:

[0027] (1) Adjust the pH value of electroplating wastewater to 8.5 with 20% NaOH solution;

[0028] (2) Start O 3 generator, press O 3 :CN - The mass ratio is 4:1 into O 3 , stir, and control the oxidation time to 45 minutes (min) before entering the reduction pool;

[0029] (3) According to hydrazine hydrate (N 2 h 2 ·H 2 O) The mass ratio of hexavalent chromium to hexavalent chromium is 0.75:1. Add the reducing agent hydrazine hydrate into the reduction pool, stir, and the waste water is sent to the precipitator for solid-liquid separation after the reduction time in the reduction pool is 30 minutes;

[0030] (4) After precipitation, the clear liquid reaches the comprehens...

Embodiment 2

[0039] A mixed electroplating wastewater containing cyanide and chromium, the pH value is 8.8, the total cyanide content is 31.5 mg / L, the hexavalent chromium content is 37.8 mg / L, and the total heavy metal ion content such as copper and zinc is 100 ~ 200 mg / L L. Since the pH value of electroplating wastewater is 8.8, there is no need to adjust the pH value. The specific treatment steps are as follows:

[0040] (1) Start O 3 generator, press O 3 :CN - (mass ratio) 5:1 into O 3 , stir, and control the oxidation time to 60 minutes before entering the reduction pool;

[0041] (3) According to hydrazine hydrate (N 2 h 2 ·H 2 O) The mass ratio of hexavalent chromium to hexavalent chromium is 1:1. Add the reducing agent hydrazine hydrate into the reduction pool, stir, and the waste water is sent to the precipitator for solid-liquid separation after the reduction time in the reduction pool is 60 minutes;

[0042] (4) After precipitation, the clear liquid reaches the comprehen...

Embodiment 3

[0051] A kind of mixed electroplating wastewater containing cyanide and chromium, the pH value is 9.2, wherein the total cyanide content is 51.3 mg / L, the hexavalent chromium content is 62.8 mg / L, and the total heavy metal ion content such as total copper, total zinc, and total chromium is Greater than 200mg / L. Because the pH value of electroplating wastewater is 9.2, there is no need to adjust the pH value. The specific treatment steps are as follows:

[0052] (1) Start O 3 generator, press O 3 :CN - (mass ratio) 6:1 into O 3 , stir, and control the oxidation time to 60 minutes before entering the reduction pool;

[0053] (3) According to hydrazine hydrate (N 2 h 2 ·H 2 O) The mass ratio of hexavalent chromium to hexavalent chromium is 1:1. Add the reducing agent hydrazine hydrate into the reduction pool, stir, and the waste water is sent to the precipitator for solid-liquid separation after the reduction time in the reduction pool is 60 minutes;

[0054] (4) After se...

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Abstract

The invention provides a processing method of electroplating wastewater containing cyanogens and chrome, comprising the following steps of: regulating the pH value of mixed electroplating wastewater containing cyanogens and chrome; introducing O3 into an oxidation pond; adding hydrazine hydrate into a reduction pond, and introducing the wastewater into a precipitator after reducing the wastewater; discharging 10-30 percent of clear solution reaching a standard after precipitation, and enabling 70-90 percent of clear solution to flow into a middle wastewater pond; regulating the pH value of the wastewater in the middle wastewater pond, and adding NaHSO3; introducing the wastewater in the middle wastewater pond into a medium filter and a precision filter; introducing the outlet water of theprecision filter for first-segment nanofiltration processing; enabling the concentrated water in the first-segment nanofiltration to enter reverse osmosis-segment processing; enabling the concentrated water in the reverse osmosis segment to finally enter second-segment nanofiltration, and enabling the permeation liquid of the second-segment nanofiltration to return to the middle wastewater pond for circular processing; and enabling the permeation concentrated water of the second-segment nanofiltration to return to an original water tank for circular processing. The method can be used for processing the mixed electroplating wastewater containing cyanogen and chrome, other heavy metals and the like, and not only can realize higher recycle rate and lower the cost, but also can reduce energy consumption.

Description

technical field [0001] The invention relates to a treatment method for electroplating wastewater containing cyanide and chromium, and belongs to the technical field of electroplating wastewater treatment. Background technique [0002] Cyanide plating and chrome plating are very common types of plating. Among them, cyanide electroplating has many advantages such as mature process, easy management, fine coating finish, beautiful color, good covering ability and dispersion ability, etc. It is the most widely used electroplating process. Highly toxic substances that are carcinogenic, teratogenic or mutagenic are extremely harmful to humans and the environment; wastewater containing hexavalent chromium produced by chromium plating also poses a greater threat to the environment. If such waste water can be regenerated and reused, it is of great significance for environmental protection and the sustainable development of the electroplating industry. [0003] Chinese patent CN10041...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C02F1/66C02F1/78C02F1/44C02F101/18C02F101/22C02F103/16
Inventor 张显球杜明霞杨柳张勇
Owner NANJING NORMAL UNIVERSITY
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