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Method for repairing mercury polluted soil through combination of low-temperature thermal desorption and chemicals

A chemical stabilization and mercury-polluted technology, applied in the restoration of polluted soil, etc., can solve the problem of low cost of soil destruction, achieve the effect of reducing the cost of using chemicals, reducing soil structure damage, and improving stabilization efficiency

Active Publication Date: 2017-11-28
AEROSPACE KAITIAN ENVIRONMENTAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In view of the defects in the heat treatment and stabilization repair methods of mercury-contaminated soil in the prior art, the purpose of the present invention is to provide a combination of thermal decomposition technology and stabilization technology to realize the recovery of various forms of mercury in mercury-contaminated soil. A method for removing and efficiently stabilizing mercury-contaminated soil with less damage to soil and lower cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The mercury-contaminated site soil left over from the relocation of a chemical factory in Hunan was taken. The average mercury content in the soil was 120mg / kg. The mercury concentration is 0.13mg / L.

[0048] (1) Air-dry the mercury-contaminated soil until the moisture content is lower than 10%, and crush it until the particle size is less than 3cm;

[0049] (2) Weigh 500 g of the pretreated soil and put it into a heat treatment device for heat treatment, set the treatment temperature to 350° C., and the treatment time to 30 minutes. The heat-treated soil is unearthed from the discharge port, the mercury in the tail gas is condensed and recovered, and then the residual mercury is removed by activated carbon adsorption. Specified limit.

[0050] (3) Add 5% sodium sulfide solution after the soil after the heat treatment is cooled to normal temperature, the addition of sodium sulfide is that the molar ratio of sulfur element and mercury element in the soil is 1:1, stir e...

Embodiment 2

[0060] Get the same soil as in Example 1, and through the same air-drying and crushing process. Weigh 500 g of the pretreated soil and put it into a heat treatment device, and heat treatment is performed under the conditions that the treatment temperature is set at 350° C. and the treatment time is 20, 30, and 40 minutes, respectively. After the heat-treated soil is cooled to normal temperature, carry out the same stabilization treatment as in Example 1, and after 3 days of maintenance, carry out leaching according to the "Solid Waste Leach Toxicity Leach Method Horizontal Oscillating Method" (HJ557-2009), and the concentration of mercury in the leach solution is 0.002 mg / L, ND, ND.

Embodiment 3

[0062] Get the same soil as in Example 1, and through the same air-drying and crushing process. Weigh 500 g of the pretreated soil and put it into a heat treatment device, and heat treatment is performed under the conditions that the treatment time is set to 30 minutes, and the treatment temperatures are respectively 250°C, 300°C, and 350°C. After the heat-treated soil was cooled to normal temperature, the same stabilization treatment as in Example 1 was carried out, and after 3 days of maintenance, the leaching was carried out according to the "Solid Waste Leaching Toxicity Leaching Method Horizontal Oscillating Method" (HJ557-2009), and the concentration of mercury in the leachate was 0.007 mg / L, 0.001mg / L, ND.

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Abstract

The invention discloses a method for repairing mercury polluted soil through combination of low-temperature thermal desorption and chemicals. The method comprises the following steps: firstly, performing low-temperature thermal desorption treatment on mercury polluted soil so as to remove metal mercury, organic combined mercury and a part of inorganic combined mercury with a low melting point in the soil; and performing a vulcanization reaction with a sulfurizing salt solution, further adding excessive ferrite precipitate S2-, further adding clay minerals and humus for adsorption, adding a pH adjusting agent to adjust the pH value of the mercury polluted soil to 6-7, and maintaining for more than 3 days. By adopting the method, removal of mercury of mercury with a low melting point in soil and immobilization of mercury of a high melting point are achieved, migration and biological availability of the mercury in the soil are greatly reduced, and compared with a conventional mercury polluted soil treatment method, the method has the characteristics of being good in repairing effect, small in chemical amount, low in energy consumption and free of soil structure damage.

Description

technical field [0001] The invention relates to a method for repairing mercury-contaminated soil, in particular to a method for repairing mercury-contaminated soil through low-temperature thermal desorption combined with stabilization, and belongs to the technical field of heavy metal soil treatment. Background technique [0002] In recent years, with the rapid development of industry and agriculture, a large amount of mercury has been released in the process of production and use, making the soil polluted by mercury more and more serious. The main sources of soil mercury pollution are atmospheric deposition, sewage irrigation, industrial pollution sources (coal-burning, chlor-alkali industry, battery factory, smelting, papermaking and other industries), agricultural pollution sources (use of pesticides and fertilizers), mercury-containing waste (thermometers, waste battery, etc.) mishandled, etc. Mercury and its compounds in the soil can enter the human body through the fo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/06B09C1/08
CPCB09C1/06B09C1/08
Inventor 邵乐史学峰刘晓月韩凤
Owner AEROSPACE KAITIAN ENVIRONMENTAL TECH CO LTD
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