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A method for removing heavy metals in zinc sulfate production wastewater

A technology for the production of wastewater and zinc sulfate, which is applied in the field of heavy metals, can solve the problems of complex process and high removal cost, achieve the effect of reducing the content of sulfide ions, reducing the amount of vulcanizing agent, and ensuring stable existence

Active Publication Date: 2017-07-07
HUNAN SHUI KOU SHAN NONFERROUS METALS GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although there are also reports on the removal method of thallium in wastewater, the process is complicated and the removal cost is high

Method used

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  • A method for removing heavy metals in zinc sulfate production wastewater
  • A method for removing heavy metals in zinc sulfate production wastewater

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The heavy metal content in the zinc sulfate production wastewater stock solution treated in this embodiment is: Zn: 520 mg / L; Cd: 86 mg / L; As: 0.0001 mg / L; Pb is not detected, Tl: 4.6125 mg / L, pH: 6.0 .

[0032] Reference figure 1 In this embodiment, a method for removing heavy metals in zinc sulfate production wastewater includes the following steps:

[0033] 1) Zinc powder replacement: The pH of zinc sulfate production wastewater is 6.0, and no adjustment is required; add zinc powder (0.453g / L) at 5 times the sum of the mass of cadmium and thallium in the wastewater, stir and mix for 2 hours to remove sulfuric acid Cadmium and thallium in zinc production wastewater are filtered and separated to obtain replacement liquid and replacement residue;

[0034] Among them, Zn in the replacement solution: 630 mg / L; Cd: 64 mg / L; Tl: 1.6638 mg / L;

[0035] 2) Neutralization and hydrolysis: adjust the pH of the replacement solution in step 1) to 9.0 with 1.5mol / L NaOH standard solution,...

Embodiment 2

[0040] The heavy metal content in the zinc sulfate production wastewater stock solution treated in this embodiment is: Zn: 875 mg / L; Cd: 110 mg / L; As: 0.0019 mg / L; Pb: 0.0785 mg / L, Tl: 4.073 mg / L, pH : 6.0.

[0041] Reference figure 1 In this embodiment, a method for removing heavy metals in zinc sulfate production wastewater includes the following steps:

[0042] 1) Zinc powder replacement: adjust the pH of zinc sulfate production wastewater to 3.5; add zinc powder (1.369g / L) at 12 times the sum of the mass of cadmium and thallium in the wastewater, stir and mix for 2.5 hours to remove zinc sulfate production wastewater Cadmium and thallium, and filter and separate to obtain replacement liquid and replacement slag;

[0043] Among them, Zn in the replacement solution: 910 mg / L; Cd: 32 mg / L; Tl: 0.131 mg / L;

[0044] 2) Neutralization and hydrolysis: adjust the pH of the replacement solution in step 1) to 10.5 with 2.5mol / L NaOH standard solution, stir and react for 2h to hydrolyze an...

Embodiment 3

[0049] The heavy metal content in the zinc sulfate production wastewater stock solution treated in this embodiment is: Zn: 673 mg / L; Cd: 141 mg / L; As: 0.0275 mg / L; Pb: 0.0278 mg / L, Tl: 4.683 mg / L, pH : 6.0.

[0050] Reference figure 1 In this embodiment, a method for removing heavy metals in zinc sulfate production wastewater includes the following steps:

[0051] 1) Zinc powder replacement: adjust the pH of zinc sulfate production wastewater to 5.0; add zinc powder (1.311g / L) at 9 times the total mass of cadmium and thallium in the wastewater, stir and mix for 3 hours to remove the zinc sulfate production wastewater Cadmium and thallium are separated by filtration to obtain replacement liquid and replacement residue;

[0052] Among them, Zn in the replacement solution: 701 mg / L; Cd: 46 mg / L; Tl: 0.3445 mg / L;

[0053] 2) Neutralization and hydrolysis: adjust the pH of the replacement solution in step 1) to 10 with 2.0mol / L NaOH standard solution, stir and react for 0.5h to hydrolyze...

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Abstract

A method for removing heavy metals in zinc sulfate production wastewater, comprising the following steps: 1) Zinc powder replacement: adjusting the pH of zinc sulfate production wastewater to 3.0-6.0; adding zinc according to 5-12 times the sum of cadmium and thallium in the wastewater 2) Neutralization and hydrolysis; 3) Sulfurization and removal of thallium: add sulphurization agent and auxiliary thallium removal agent to the neutralization solution, and the sulphurization precipitation reaction is 1~ 2h, make the thallium content in the wastewater ≤0.005mg / L; send the replacement slag in step 1) and the neutralization slag in step 2) directly to the zinc sulfate production workshop as raw materials for recycling. The method is simple to operate, low in cost, and the removal rate of thallium is as high as 99.9%; the auxiliary thallium removal agent can react with thallium to form a relatively stable complex complex state substance, which plays an auxiliary role in the removal of thallium by the vulcanizing agent; recycling waste residues reduces waste residues Disposal costs and production costs of zinc sulphate.

Description

Technical field [0001] The invention relates to a method for removing impurities from zinc sulfate production wastewater, in particular to a method for removing cadmium, zinc, thallium and other heavy metals in zinc sulfate production wastewater. Background technique [0002] Wastewater containing heavy metals in the zinc sulfate production industry has not been properly treated, and there is also a lack of consideration for the recycling and reuse of heavy metal resources. Most of the wastewater treatment processes are: first neutralize with lime, then sulfide, wastewater with complex heavy metal components Electric flocculation and other deep thallium removal measures must be added, and the process flow is complicated. Among them, lime neutralization refers to adding lime milk to wastewater containing heavy metals, and using the OH produced by lime milk - It chemically reacts with heavy metal ions to form insoluble metal hydroxide precipitates, which are separated by filtration...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C02F101/20C02F103/34
Inventor 付绸琳谭振华张晓林杜红陈国兰付高明
Owner HUNAN SHUI KOU SHAN NONFERROUS METALS GRP