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Method for treating arsenic-containing wastewater with recyclable composite salt precipitation agent

A compound salt and precipitant technology, applied in flocculation/sedimentation water/sewage treatment, water/sewage treatment, chemical instruments and methods, etc. The effect of resource recovery and recycling, fast filtration, and large concentration range

Active Publication Date: 2019-12-31
深圳准诺检测有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method is easy to implement and low in cost, the waste water after recovering arsenic has not been effectively treated, and the reducing agent cannot be recycled.

Method used

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  • Method for treating arsenic-containing wastewater with recyclable composite salt precipitation agent
  • Method for treating arsenic-containing wastewater with recyclable composite salt precipitation agent
  • Method for treating arsenic-containing wastewater with recyclable composite salt precipitation agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031]With n(Ca) / n(As)=1.05, n(Cu) / n(As)=0.45, n(Fe) / n(As)=1.20, n(Zn) / n(As)=1.20 After mixing calcium chloride, zinc chloride, ferrous sulfate and copper sulfate pentahydrate, add it to 4L 9.8g / L As(III)-containing wastewater (initial pH=1.8), stir at room temperature for 10min, and then use The sodium hydroxide solution was stirred to adjust the pH of the solution to 8.5, continued to stir for 0.5 h, and then filtered to obtain arsenic-containing slag and arsenic-precipitated liquid. The content of each component in the solution after arsenic precipitation is shown in Table 1:

[0032] Table 1 Contents of each component in the liquid after arsenic precipitation (mg / L)

[0033]

[0034] Under the conditions of liquid-solid ratio 3:1 (mL:g), sulfuric acid concentration 0.8mol / L, and leaching temperature 25°C, the arsenic-containing slag was leached for 0.5h, and the leaching slag and leaching liquid were obtained by filtration, and the content of each component in the leac...

Embodiment 2

[0048] With n(Ca) / n(As)=1.0, n(Cu) / n(As)=0.6, n(Fe) / n(As)=1.5, n(Zn) / n(As)=1.5 After mixing calcium chloride, zinc chloride, ferrous sulfate and copper sulfate pentahydrate, add it to 4L 2.39g / L arsenic-containing wastewater (initial pH=1.9), stir at room temperature for 10min, and then add sodium hydroxide The pH of the solution was adjusted to 8.5 under the condition of stirring, and the stirring reaction was continued for 1.5 hours, and then filtered to obtain arsenic-containing slag and arsenic-precipitated liquid. The content of each component in the solution after arsenic precipitation is as shown in Table 4:

[0049] Contents of each component in the solution after table 4 arsenic precipitation (mg / L)

[0050]

[0051] The arsenic-containing slag was leached for 1 hour under the conditions of sulfuric acid concentration 1.7mol / L, liquid-solid ratio 5:1, and leaching temperature 30°C, and the leaching residue and leaching solution were obtained by filtration. The ars...

Embodiment 3

[0063] With n(Ca) / n(As)=16.8, n(Cu) / n(As)=7.2, n(Fe) / n(As)=19.2, n(Zn) / n(As)=19.2 Mix calcium chloride, zinc chloride, ferrous sulfate and copper sulfate pentahydrate and add them to 4L 50mg / L arsenic-containing wastewater (initial pH=1.9), stir at room temperature for 10min, and then use sodium hydroxide solution Adjust the pH of the solution to 8.7 under stirring conditions, continue to stir and react for 1.5 hours, and then filter to obtain arsenic-containing slag and arsenic-precipitated liquid. The contents of each component in the solution after arsenic precipitation are shown in Table 7:

[0064] Contents of each component in the solution after table 7 arsenic precipitation (mg / L)

[0065]

[0066] It can be seen from Table 7 that the concentration of each element in the waste water can be kept within the range of the "Comprehensive Wastewater Discharge Standard" (GB8978-1996) by expanding the compound salt ratio and treating low-concentration arsenic-containing was...

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Abstract

The invention discloses a method for treating arsenic-containing wastewater with a recyclable composite salt precipitation agent. The method comprises the following steps of (1) adding composite saltinto the arsenic-containing wastewater to be precipitated, adjusting the pH value to be 7.5-9.0 by alkali for reaction, and performing filtering to obtain arsenic-containing residues and post-arsenic-precipitation liquid, wherein the composite salt is a mixture of soluble salts of Ca, Cu, Fe and Zn; (2) leaching the arsenic-containing residues with sulfuric acid, and performing filtering to obtainleaching liquid and leaching residues; (3) introducing SO2 into the leaching liquid for reduction, and performing evaporation concentration, cooling crystallization and filtering to obtain arsenic trioxide and arsenic removal mother liquid; and (4) supplementing the soluble salts to the arsenic removal mother liquid according to the concentration of the composite salt in the step (1), and returning to the step (1) for cycle use. According to the method, the arsenic-containing wastewater can be directly treated, oxidation is not needed, arsenic in the arsenic-containing residues can be efficiently recovered with the low energy consumption, the complex salt can be recycled, and the concentration range of the treated wastewater is wide.

Description

technical field [0001] The present invention relates to a method for resourceful treatment of arsenic-containing wastewater, in particular to a method for treating arsenic-containing wastewater by using a recyclable compound salt precipitant. A method for recovering arsenic trioxide and reusing compound salt. It belongs to the field of waste water resource utilization. Background technique [0002] Arsenic is a carcinogen that is toxic to the human body and other organisms. The poisoning dose to humans is 0.01-0.052g, and the lethal dose is 0.06-0.2g. Its toxicity is related to their chemical properties and valence states. Generally, inorganic arsenic compounds are more toxic than organic arsenic compounds. Trivalent arsenic is about 60 times more toxic than pentavalent arsenic. The smelting of arsenic compounds and the development and smelting of other non-ferrous metals will cause arsenic pollution to the environment, and because arsenic compounds can be used as raw mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C01G28/00C02F101/10
CPCC02F1/5236C01G28/005C02F2101/103
Inventor 郑雅杰徐蕾龙华
Owner 深圳准诺检测有限公司
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