Processing method of electroplating wastewater containing cyanogens and chrome

A treatment method and technology for electroplating wastewater, applied in metallurgical wastewater treatment, neutralized water/sewage treatment, oxidized water/sewage treatment, etc., can solve the problems of unpublished concentrated water treatment method, unsuitable treatment, high energy consumption, etc., to achieve Significant energy saving effect, simplified concentrated water treatment process, and reduced treatment cost

Inactive Publication Date: 2010-11-03
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 Although the water quality of this process is good, the investment Large, high energy consumption, unpublished concentrated water treatment method

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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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Effect test

Embodiment 1

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

[0027] (1) Adjust the pH 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, control the oxidation time to be 45 minutes (min) and then enter the reduction tank;

[0029] (3) Press hydrazine hydrate (N 2 H 2 ·H 2 O) The mass ratio to hexavalent chromium is 0.75:1, add the reducing agent hydrazine hydrate into the reduction tank, stir, and the wastewater is sent to the precipitator for solid-liquid separation after the reduction time in the reduction tank is 30min;

[0030] (4) The clear liquid after precipitation meets the comprehensive sewage discharge standard (GB...

Embodiment 2

[0039] A mixed electroplating wastewater containing cyanide and chromium, the pH value is 8.8, the total cyanide content is 31.5mg / L, the hexavalent chromium content is 37.8mg / L, and the total heavy metal ion content such as copper and zinc is 100-200mg / 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 enter the reduction tank after 60min;

[0041] (3) Press hydrazine hydrate (N 2 H 2 ·H 2 O) with a mass ratio of hexavalent chromium of 1:1, add reducing agent hydrazine hydrate to the reduction tank, stir, and the wastewater is sent to the precipitator for solid-liquid separation after the reduction time in the reduction tank is 60min;

[0042] (4) The clear liquid after precipitation reaches the comprehensive sewage discharge standard (GB8978-1996), of which ...

Embodiment 3

[0051] A mixed electroplating wastewater containing cyanide and chromium, with a pH value of 9.2, wherein the total cyanide content is 51.3 mg / L, the hexavalent chromium content is 62.8 mg / L, and the total copper, total zinc, total chromium and other total heavy metal ions content are More than 200mg / L. Since 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 enter the reduction tank after 60min;

[0053] (3) Press hydrazine hydrate (N 2 H 2 ·H 2 O) with a mass ratio of hexavalent chromium of 1:1, add reducing agent hydrazine hydrate to the reduction tank, stir, and the wastewater is sent to the precipitator for solid-liquid separation after the reduction time in the reduction tank is 60min;

[0054] (4) The clear liquid after precipitation meets the comprehensive sewag...

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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 the precision 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 method for treating cyanogen-containing and chromium-containing electroplating wastewater, 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 technology, easy management, fine coating, beautiful color, good covering ability and dispersion ability, etc. It is the most widely used electroplating process. However, a large amount of cyanide-containing wastewater is produced in the cyanide electroplating process, which has Carcinogenic, teratogenic or mutagenic highly toxic substances are extremely harmful to humans and the environment; the hexavalent chromium-containing wastewater produced by chrome plating also poses a greater threat to the environment. If such wastewater can be regenerated and reused, it is of great significance for envi...

Claims

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Application Information

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Patent Type & Authority Applications(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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