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Treatment method for wastewater after vanadium precipitation

A vanadium-precipitated waste water and treatment method technology, applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., can solve the problem of high COD in discharged waste water, failure to meet discharge standards, failure to meet standards Discharge and other issues, to achieve the effect of reducing the occupied area and investment scale, realizing the reuse of resources, and high efficiency of wastewater treatment

Inactive Publication Date: 2012-11-28
CITIC JINZHOU METAL
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Problems solved by technology

The disadvantages are: after the treatment of industrial wastewater containing chromium and vanadium, the COD of the wastewater is difficult to control, easily exceeds the standard, and cannot be discharged up to the standard. Secondary treatment is required, and the process is long.
Its disadvantages are: after the treatment of hexavalent chromium wastewater, COD and total chromium (TCr) are difficult to control, and it is easy to cause single or multiple indicators such as COD and total chromium (TCr) to exceed the standard and fail to meet the discharge standard
In order to ensure that the discharge of hexavalent chromium in wastewater meets the standard, a large amount of sodium pyrosulfite is added (the weight ratio of sodium pyrosulfite to hexavalent chromium is 3.5:1 to 5:1), far exceeding the theoretical addition amount (the theoretical addition amount is the weight of hexavalent chromium 2.74 times of that), the reaction time is longer, and after the reaction, the residual amount of sodium pyrosulfite (dissociated into bisulfite in the solution) is too much, resulting in high COD in the effluent wastewater, generally exceeding 300mg / L, and the COD cannot reach the wastewater Discharge standard, secondary treatment must be carried out through oxidation and other methods; after the reduction of wastewater, trivalent chromium is neutralized and precipitated with sodium hydroxide. Due to the strong alkalinity of sodium hydroxide, it is difficult to control the pH value after neutralization. When the pH value ≥ 8.5, Cr(OH) 3 The precipitate redissolves in solution to form Cr(OH) 4 — , resulting in a high content of total chromium (TCr) in the filtrate, which usually exceeds 1.5mg / L and cannot be discharged up to the standard. The filtrate usually must undergo secondary treatment to reduce the total chromium content

Method used

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  • Treatment method for wastewater after vanadium precipitation
  • Treatment method for wastewater after vanadium precipitation
  • Treatment method for wastewater after vanadium precipitation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Such as figure 1 Shown, the concrete steps of the treatment method of acidic vanadium precipitation wastewater are as follows:

[0033] (1) put 20m 3The acidic vanadium precipitation wastewater is injected into the wastewater treatment tank, and the concentration of chromium (Ⅵ) in the vanadium precipitation wastewater is detected to be 325mg / L, and the concentration of vanadium (Ⅴ) is 140mg / L. The amount is 2.0 times the sum of the mass of chromium (Ⅵ) and vanadium (Ⅴ) in the vanadium precipitation wastewater) to carry out the main reduction reaction, the temperature of the first main reduction reaction is 40℃~45℃, and the reaction time is 20min, so that the Chromium (Ⅵ) and trace vanadium (Ⅴ) are reduced to chromium (Ⅲ) and vanadium (Ⅳ) respectively;

[0034] (2) After detecting the concentration of chromium (Ⅵ) in the vanadium precipitation wastewater after the first reduction is 101 mg / L, and the concentration of vanadium (Ⅴ) is 38 mg / L, add 44.5 kg of auxiliary r...

Embodiment 2

[0037] (1) will 30m 3 The acidic vanadium precipitation wastewater was injected into the wastewater treatment tank, and the concentration of chromium (Ⅵ) in the vanadium precipitation wastewater was detected to be 1302 mg / L, and the concentration of vanadium (Ⅴ) was 171 mg / L, and 141.4 kg of solid sodium metabisulfite (sodium metabisulfite) as the main reducing agent was added to the wastewater treatment tank. The amount added is 3.2 times the sum of the mass of chromium (Ⅵ) and vanadium (Ⅴ) in the vanadium precipitation wastewater), the temperature of the first main reduction reaction is 85°C to 90°C, and the reaction time is 60min, so that the chromium (Ⅵ) in the vanadium precipitation wastewater ) and trace vanadium (Ⅴ) are reduced to chromium (Ⅲ) and vanadium (Ⅳ) respectively;

[0038] (2) After detecting the concentration of 50 mg / L of chromium (Ⅵ) and 21 mg / L of vanadium (Ⅴ) in the vanadium precipitation wastewater after the first reduction, add 55.4 kg of auxiliary redu...

Embodiment 3

[0041] (1) will 40m 3 The acidic vanadium precipitation wastewater was injected into the wastewater treatment tank, and the concentration of chromium (Ⅵ) in the vanadium precipitation wastewater was detected to be 876 mg / L, and the concentration of vanadium (Ⅴ) was 182 mg / L. Then, 101.6 kg of solid sodium metabisulfite (sodium metabisulfite), the main reducing agent, was added to the wastewater treatment tank. The amount added is 2.4 times the sum of the mass of chromium (Ⅵ) and vanadium (Ⅴ) in the vanadium precipitation wastewater), the temperature of the first main reduction reaction is 55°C-60°C, and the reaction time is 25min, so that the chromium (Ⅵ) in the vanadium precipitation wastewater ) and trace vanadium (Ⅴ) are reduced to chromium (Ⅲ) and vanadium (Ⅳ) respectively;

[0042] (2) After detecting the concentration of chromium (Ⅵ) in the vanadium precipitation wastewater after the first reduction is 47mg / L, and the concentration of vanadium (Ⅴ) is 24mg / L, add 51.1kg o...

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Abstract

A treatment method for wastewater after vanadium precipitation comprises: detecting the concentrations of chromium (VI) and vanadium (V) in the wastewater after vanadium precipitation, and adding solid sodium pyrosulfite according to the total mass of the chromium (VI) and the vanadium (V) for a first reduction reaction; detecting the concentrations of the chromium (VI) and the vanadium (V) in the wastewater after vanadium precipitation and after the first reduction reaction, and adding ferrous sulphate or ferrous chloride according to the total mass of the chromium (VI) and the vanadium (V) for a second auxiliary reduction reaction; and adjusting pH value by using alkali, neutralizing, precipitating, press filtering, and the wastewater reaching the discharge standard for discharging. The indexes of chemical oxygen demand (COD), the suspension solids (SS), the total chromium (TCr) and the chromium (VI) are easy to control after the wastewater after vanadium precipitation being treated by using the method, and all the indexes meet the wastewater discharge standard of the nation. By using the method, a small quantity of waste residue is produced, the chromium and the vanadium are fully enriched in waste residue, and the waste residue can be used as the raw material for producing the vanadium and chromium, realizing the recycle of resource, eliminating environmental pollution and reducing wastewater treatment cost.

Description

technical field [0001] The invention belongs to the field of wastewater treatment, in particular to a method for treating chromium (VI) and vanadium (V) in acidic vanadium precipitation wastewater. Background technique [0002] Acidic vanadium precipitation wastewater is wastewater containing chromium (Ⅵ) and vanadium (Ⅴ) produced during the production process of vanadium pentoxide or vanadium trioxide, which contains chromium (Ⅵ) and vanadium (Ⅴ). The concentration of vanadium (Ⅴ) is 0.3g / L~2.5g / L, the concentration of vanadium (Ⅴ) is 0.10g / L~0.25g / L, and the pH value is 1~3. Both chromium (Ⅵ) and vanadium (Ⅴ) have very strong toxicity, especially chromium (Ⅵ) seriously pollutes the ecological environment. It is enriched in organisms through the food chain and cannot be decomposed by microorganisms. Water-soluble chromium (Ⅵ) has been Listed as one of the most harmful chemical substances to the human body. [0003] At present, the main methods for industrially tre...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F101/20C02F101/22
Inventor 齐牧崔传海孙海英李宝玉杨锦铭马锦红鲁少冲庄立军
Owner CITIC JINZHOU METAL
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