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Method for removing mercury in hydrometallurgy acid wastewater

A technology of acidic wastewater and hydrometallurgy, applied in the fields of metallurgical wastewater treatment, chemical instruments and methods, water pollutants, etc., can solve problems such as human and environmental damage, high toxicity, environmental problems, etc., to improve precipitation efficiency, prevent Effects of hydrogen sulfide gas

Inactive Publication Date: 2015-12-09
BAIYIN NONFERROUS GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Mercury, commonly known as mercury, has a low melting point and boiling point. It is a silvery-white shiny heavy liquid in its elemental state. It is chemically stable and insoluble in acid and alkali. Mercury can evaporate at room temperature. Mercury vapor and mercury compounds Most of them are highly toxic. In the process of hydrometallurgy, mercury is oxidized into compounds in the boiling furnace stage, and enters the sulfuric acid system along with the smelting flue gas. In the sulfuric acid purification process, along with the dilute acid washing process, the mercury in the flue gas enters the washing acid wastewater , the mercury in the above production process enters the environment, which will cause serious environmental problems
[0003] At present, domestic enterprises generally adopt the sulfidation method, that is, directly add sodium sulfide to the waste acid to precipitate the mercury in the dirty acid. Excessive sodium sulfide will produce highly toxic hydrogen sulfide gas in acidic environment, causing serious harm to human body and environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] The hydrometallurgical acidic wastewater is settled, the sediment is piled up after the sedimentation, and the rare precious metals are recovered. The supernatant of the settled acidic wastewater enters the neutralization reaction tank, and the calcium hydroxide solution is added for neutralization. The pH of the solution is monitored by a pH meter. 5 to 6 is regarded as the end point of the neutralization reaction; filter the neutralized acid wastewater, send the neutralized slag to the slag yard for stacking, and send the neutralized clear liquid to the intermediate reaction tank. The volume of the clear liquid is 99660252cm3, and the mercury content in the clear liquid after neutralization is 90.76mg / l. Add 3.5kg of sodium sulfide to react for 45-60min. HgS, Hg and S, then add 2kg flocculant to form insoluble large particles, pump the neutralized clear liquid into the automatic backwash surface filter for solid-liquid separation, and the separated neutralized clear li...

Embodiment 2

[0014] The hydrometallurgical acidic wastewater is settled, the sediment is piled up after the sedimentation, and the rare precious metals are recovered. The supernatant of the settled acidic wastewater enters the neutralization reaction tank, and the calcium hydroxide solution is added for neutralization. The pH of the solution is monitored by a pH meter. 5 to 6 is regarded as the end point of the neutralization reaction; filter the neutralized acid wastewater, send the neutralized slag to the slag yard for stacking, and send the neutralized clear liquid to the intermediate reaction tank. The volume of the clear liquid is 284900285cm3, and the mercury content in the clear liquid after neutralization is 51.92 mg / l. Add 5.7 kg of sodium sulfide to react for 45-60 minutes. At the same time, blow the compressed air on the clear liquid after neutralization to ensure that the liquid is evenly mixed and generate insoluble HgS , Hg and S, then add 5.6kg flocculant to form insoluble la...

Embodiment 3

[0017] The hydrometallurgical acidic wastewater is settled, the sediment is piled up after the sedimentation, and the rare precious metals are recovered. The supernatant of the settled acidic wastewater enters the neutralization reaction tank, and the calcium hydroxide solution is added for neutralization. The pH of the solution is monitored by a pH meter. 5 to 6 is regarded as the end point of the neutralization reaction; filter the neutralized acid wastewater, send the neutralized slag to the slag yard for stacking, and send the neutralized clear liquid to the intermediate reaction tank. The volume of the clear liquid is 382482987cm3, and the mercury content in the clear liquid after neutralization is 176.47mg / l. Add 26kg of sodium sulfide to react for 45-60min. Hg and S, then add 7.6kg flocculant to form insoluble large particles, pump the neutralized clear liquid into the automatic backwash surface filter for solid-liquid separation, and the separated neutralized clear liqu...

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Abstract

The invention belongs to the technical field of chemical engineering and relates to a method for removing mercury in hydrometallurgy acid wastewater. According to the scheme, the method includes the steps that sedimentation is conducted on the hydrometallurgy acid wastewater, and a calcium hydroxide solution is added into acid wastewater supernatant after sedimentation to be neutralized till the pH is 5-6; filter pressing is conducted on the neutralized acid wastewater, sodium sulfide and flocculant are sequentially added into the neutralized supernatant for mercury removal, and then solid-liquid separation is carried out on the neutralized supernatant. According to the method, a lime neutralizing-sodium sulfide sedimentation method is adopted for treatment of waste acid containing mercury, then the sodium sulfide and the flocculant are added, hence, gaseous hydrogen sulfide can be effectively prevented from being generated, and sedimentation efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a method for removing mercury from hydrometallurgical acid wastewater. Background technique [0002] Mercury, commonly known as mercury, has a low melting point and boiling point. It is a silvery-white shiny heavy liquid in its elemental state. It is chemically stable and insoluble in acid and alkali. Mercury can evaporate at room temperature. Mercury vapor and mercury compounds Most of them are highly toxic. In the process of hydrometallurgy, mercury is oxidized into compounds in the boiling furnace stage, and enters the sulfuric acid system along with the smelting flue gas. In the sulfuric acid purification process, along with the dilute acid washing process, the mercury in the flue gas enters the washing acid wastewater , the mercury in the above-mentioned production process enters the environment, which will cause serious environmental problems. [0003] At present, d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F103/16C02F101/20
Inventor 杨随心王新元杨宁宁
Owner BAIYIN NONFERROUS GROUP