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A treatment process for electroplating wastewater containing cyanide and chromium

A treatment process and chromium electroplating technology, which is applied in metallurgical wastewater treatment, water/sewage treatment, water/sewage multi-stage treatment, etc. It can solve the problems of difficult treatment of wastewater and increase the difficulty of treatment, so as to strengthen the purification effect and reduce the secondary Pollution, the effect of improving purification efficiency

Active Publication Date: 2018-12-18
NORTHERN ENG DESIGN & RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In reality, it is difficult for electroplating enterprises to completely separate the water quality. Chromium-containing wastewater is often mixed with cyanide or cyanide-containing wastewater often contains hexavalent chromium or trivalent chromium. The mixed wastewater is more difficult to treat, especially in some enterprises. Completely mixed, wastewater It also contains a large amount of iron salt, which is easy to form ferricyanide, which cannot be oxidized by sodium hypochlorite, which increases the difficulty of handling, and often the cyanide and total chromium are not up to the standard

Method used

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  • A treatment process for electroplating wastewater containing cyanide and chromium
  • A treatment process for electroplating wastewater containing cyanide and chromium
  • A treatment process for electroplating wastewater containing cyanide and chromium

Examples

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Effect test

Embodiment 1

[0028] The daily discharge of electroplating wastewater in an electroplating factory is 2,000 tons. Among them, the water quality of the electroplating wastewater containing cyanide and chromium in this electroplating factory is shown in Table 1

[0029] Table 1

[0030]

[0031] This embodiment includes the following steps:

[0032] (1) The above-mentioned cyanide-containing and chromium-containing electroplating wastewater is pretreated through an iron-carbon micro-electrolysis reactor, and the refractory macromolecules and biochemical organic substances are degraded into small molecules by iron-carbon micro-electrolysis method, so as to improve the biodegradability of organic wastewater .

[0033] (2) Discharge the waste water after step (1) into the primary sedimentation tank, and use alkali, such as sodium hydroxide or calcium hydroxide, to adjust the pH to 9~11. Since the wastewater contains a large amount of ferrous ions and some ferrocyanide, ferric ions are need...

Embodiment 2

[0040] The indicators of electroplating wastewater treated in this example are shown in Table 1.

[0041] This embodiment includes the following steps:

[0042] (1) Pass the above cyanide-containing and chromium-containing electroplating wastewater through the iron-carbon micro-electrolysis reactor for pretreatment, and use the iron-carbon micro-electrolysis method to degrade the refractory macromolecules and biochemical organics into small molecules, so as to improve the biochemical properties of organic wastewater sex.

[0043] (2) Discharge the waste water after step (1) into the primary sedimentation tank, and use alkali, such as sodium hydroxide or calcium hydroxide, to adjust the pH to 9~11. Since the wastewater contains a large amount of ferrous ions and some ferrocyanide, ferric ions are needed to remove ferrocyanide, so sodium hypochlorite is added to oxidize part of the ferrous iron into ferric iron, so that the wastewater contains ferrous iron at the same time , f...

Embodiment 3

[0050] The indicators of electroplating wastewater treated in this example are shown in Table 1.

[0051] like figure 1 As shown, this embodiment includes the following steps:

[0052] (1) This step is a pretreatment stage. The above-mentioned cyanide-containing and chromium-containing electroplating wastewater has strong acidity, generally at a pH of about 3. The above-mentioned cyanide-containing and chromium-containing electroplating wastewater is passed through an iron-carbon micro-electrolysis reactor, The electrolysis method degrades the refractory macromolecules and biochemical organics into small molecules, and improves the biodegradability of organic wastewater. This embodiment uses a swirl micro-electrolysis reactor, preferably, a swirl with the patent number ZL201420467908.9 The micro-electrolysis reactor is filled with micro-electrolysis packing, and the waste water is passed through the equipment through the pump, and the residence time is 10~20min. Through the m...

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Abstract

The invention relates to a treatment process of electroplating wastewater containing cyanogen and chromium. The treatment process is characterized by comprising the following steps: (1) enabling the electroplating wastewater containing cyanogen and chromium to flow through an iron-carbon micro-electrolysis reactor; (2) adjusting pH to be 9-11, then adding sodium hypochlorite, reacting for 10-60 minutes, controlling the pH value to be 4-6, reacting for 10-60 minutes, then adding a flocculant for carrying out flocculation treatment, and then carrying out precipitation treatment; (3) adjusting the pH value to be 10-12, then adding sodium hypochlorite, enabling oxidation-reduction potential of the treated wastewater to be 350mV or above, reacting for 30-60 minutes, and then adding active carbon and reacting for 10-60 minutes; and (4) adding the flocculant and then precipitating. The treatment process is capable of removing harmful materials in the wastewater, particularly removing iron-cyanogen complex which is difficultly removed by conventional methods, adsorbing heavy metals and ensuring that various indexes of the treated electroplating wastewater containing cyanogen and chromium reach the standards.

Description

technical field [0001] The invention relates to a treatment process for electroplating wastewater containing cyanide and chromium, and belongs to the technical field of electroplating wastewater treatment. Background technique [0002] The electroplating industry is usually divided into cyanide-containing wastewater, chromium-containing wastewater, heavy metal wastewater, and acid-base wastewater according to the types of pollutants. Among them, cyanide- and chromium-containing wastewater contains highly toxic cyanide and hexavalent chromium, and it is discharged to Water can be hazardous to aquatic life. Under normal circumstances, cyanide-containing and chromium-containing wastewater need to be collected and treated separately. Because the pH of hexavalent chromium in chromium-containing wastewater is acidic, generally between 2 and 3, it needs to be reduced with a reducing agent and then chemically precipitated, while the pH of cyanide-containing wastewater requires Unde...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/06C02F103/16
CPCC02F1/281C02F1/461C02F1/56C02F1/725C02F9/00C02F2103/16
Inventor 孟宪礼李瑞杰李洪瑞付丽霞张建磊李德喜李相龙
Owner NORTHERN ENG DESIGN & RES INST CO LTD
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