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Purification method of wastewater containing heavy metal and arsenic

A technology for wastewater purification and heavy metals, which is applied in chemical instruments and methods, water pollutants, and multi-stage treatment of water/sewage, etc. It can solve the problems of incomplete metal sulfide precipitation, high wastewater treatment costs, and unsatisfactory purification effects. Achieve the effect of improving liquid-solid separation performance, stable performance, and easy storage and storage

Inactive Publication Date: 2012-11-07
CENT SOUTH UNIV
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  • Summary
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the neutralization hydrolysis method is simple to operate, the purification effect is often not ideal, because the hydrolysis pH of different metal ions is different, and the ions with different valence states of the same metal have different forms of existence under the same pH condition.
Although the solubility of heavy metal sulfides and arsenic sulfides in water is very small, the precipitation of metal sulfides is not complete when sulfides are added to heavy metal wastewater with low concentration.
Therefore, for the heavy metal-containing wastewater with complex components, it is often necessary to use a combination of multiple purification methods to treat it before it can be discharged up to the standard, which makes the wastewater purification process complicated and the wastewater treatment cost high.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Acid wastewater produced by smelting enterprises 10m 3 , the heavy metal elements and contents contained in it are shown in Table 1. First, ferric sulfate is added to make the SO in the wastewater 4 2- The concentration rises to 8.6g / L, and then the high-valent chromium in the solution is reduced to Cr 3+ Add the reducing agent sodium sulfite to 1.1 times the stoichiometric number, stir at room temperature for 10 minutes, then add limestone, stir at 10°C for 5 hours, pre-adjust the pH value of the solution to 3.8, then add lime milk, stir at room temperature for 1 hour, and control the pH value of the solution 8.7, heavy metals and harmful elements such as arsenic in the solution are precipitated, and the filtrate and filter residue are obtained by filtration; the filtrate is discharged up to the standard, and the filter residue is used for smelting furnace batching. The acid wastewater purification results are shown in Table 1:

[0016] Table 1 Acidic wastewater pur...

Embodiment 2

[0019] 2000ml of vanadium raffinate from stone coal acid leaching. The composition of the raffinate is shown in Table 2. Since the vanadium extraction raffinate itself contains a large amount of sulfate, there is no need to supplement sulfate ions, and the solution has been added to the solution before extraction of vanadium. The vanadium and chromium in the solution exist in a low-valence state, so there is no need to supplement sulfate ions and add a reducing agent for reduction. Limestone is directly added to the vanadium extraction raffinate, stirred at room temperature for 2.5 hours, and the pH value of the solution is pre-adjusted. to 4.0, then add calcium oxide, stir at 60°C for 2.5 hours, control the pH of the solution to 11.2, precipitate harmful elements such as heavy metals and arsenic in the solution, and filter to obtain the filtrate and filter residue; the filtrate is returned to stone coal for acid leaching of vanadium for recycling , and the filter residue is st...

Embodiment 3

[0023] Analyze 5000ml of waste water in the laboratory waste water pool, the heavy metal elements and content contained in it are shown in Table 3, first add Glauber's salt to make the SO in the waste water 4 2- The concentration rises to 35.2g / L, and then the high-priced manganese and chromium in the solution are reduced to Mn 2+ and Cr 3+ Add reducing agent iron powder 5 times the total stoichiometric amount, stir at 10°C for 180 minutes, then add calcium carbonate, stir at 40°C for 1 hour, pre-adjust the pH value of the solution to 5.2, then add calcium hydroxide, stir at 80°C for 0.5 hour, Control the pH value of the solution to 8.5, so that harmful elements such as heavy metals and arsenic in the solution are precipitated, and the filtrate and filter residue are obtained by filtration; Analysis laboratory wastewater purification results are shown in Table 3:

[0024] Table 3 Analysis of Laboratory Wastewater Purification Results

[0025]

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PUM

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Abstract

The invention provides a purification method of wastewater containing heavy metal and arsenic. The purification method mainly comprises the process steps as follows: adding sulfuric acid or soluble sulfate into the wastewater to supplement sulfate ions; then adding a reductant to reduce high-valence manganese, chromium and vanadium in the wastewater; adding calcium carbonate to pre-adjust the pH value of the solution; adding lime for neutralization, precipitating and separating out heavy metals and harmful elements such as arsenic from the wastewater, and packaging the precipitates in gypsum slag, discharging or reusing filtered liquid after satisfying standards, and recycling filter residue. The purification method provided by the invention has the advantages of being simple in process, good in purification effect, low in cost and environment-friendly.

Description

technical field [0001] The invention relates to a method for purifying waste water containing heavy metals and arsenic. The invention belongs to the technical field of wastewater purification. Background technique [0002] Metallurgical and chemical industry processes will produce a large amount of waste water containing heavy metals such as vanadium, chromium, manganese, cobalt, nickel, antimony, bismuth, copper, zinc, cadmium, lead, tin and harmful elements such as arsenic. At present, there are many purification methods for heavy metal-containing wastewater, including neutralization hydrolysis, sulfide precipitation, insoluble chloride precipitation, oxidation-reduction chemical method, microbial method, etc. Although the neutralization hydrolysis method is simple to operate, the purification effect is often not ideal, because the hydrolysis pH of different metal ions is different, and the ions of different valence states of the same metal have different forms of existen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F101/20
Inventor 王学文王明玉
Owner CENT SOUTH UNIV
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