Chemical stabilization repair method of lead contaminated soil

A lead-contaminated soil and repair method technology, applied in the field of contaminated soil regeneration, can solve the problems of limited molar ratio dosage, limited dosage, high soil moisture content, etc., and achieve the goal of reducing secondary pollution and reducing phosphorus Leaching, reducing the effect of phosphorus leaching

Inactive Publication Date: 2019-02-22
重庆市环境科学研究院 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, for high-concentration lead-contaminated soils, under the same dosage molar ratio, the stabilization and repair effect of ferrous sulfide particle suspension is not as good as that of phosphate based on the different reaction me...

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  • Chemical stabilization repair method of lead contaminated soil

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Experimental program
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preparation example Construction

[0030] 1) Preparation of ferrous sulfide particle suspension;

[0031] 2) Soil pretreatment;

[0032]2.1) Use a crusher to crush and screen the contaminated soil to obtain contaminated soil with a particle size of less than 10 cm, and measure the lead content in the soil;

[0033] 2.2) weighing the crushed and sieved contaminated soil obtained in step 2.1);

[0034] 3) Soil chemical stabilization treatment;

[0035] 3.1) Add a certain amount of sodium phosphate solution and sodium chloride solution to the pretreated contaminated soil obtained in step 2.2) to keep the moisture content (water / soil) of the contaminated soil at 30% to 50%. Water can be added, followed by medium-speed mechanical stirring, the stirring rate is controlled at 500-1000rpm, and the stirring time is controlled at 5-10min, so that the contaminated soil and the agent are mixed evenly;

[0036] 3.2) Moisturize and maintain the polluted soil obtained in step 3.1) for 2 to 5 days, then add a certain amount...

Embodiment 1

[0043] Use a crusher to crush the contaminated soil and sieve it to obtain contaminated soil with a particle size of less than 10cm. The concentration of lead in the soil is 200mg / kg, and the weight of the soil is 20kg;

[0044] For the first chemical stabilization treatment, add sodium phosphate solution and sodium chloride solution to the polluted soil, the molar ratio of sodium phosphate addition to lead content in polluted soil is 2:1, the molar ratio of sodium chloride addition to lead content in polluted soil The ratio is 0.5:1; add water to keep the moisture content of the contaminated soil at 30%; mechanically stir at a medium speed at 500rpm for 5 minutes to mix the contaminated soil and the agent evenly, and then moisturize and maintain for 2 days;

[0045] In the second chemical stabilization treatment, ferrous sulfide particulate suspension and calcium carbonate are added to the soil. The molar ratio of the ferrous sulfide particulate addition to the lead content of...

Embodiment 2

[0048] Use a crusher to crush the contaminated soil and sieve it to obtain contaminated soil with a particle size of less than 6cm. The concentration of lead in the soil is 500mg / kg, and the weight of the soil is 30kg;

[0049] For the first chemical stabilization treatment, add sodium phosphate solution and sodium chloride solution to the polluted soil, the molar ratio of sodium phosphate addition to the lead content of the polluted soil is 6:1, the molar ratio of the sodium chloride addition to the lead content of the polluted soil The ratio is 1.3:1; add water to keep the moisture content of the contaminated soil at 40%; mechanically stir at a medium speed at 750rpm for 8 minutes to mix the contaminated soil and the agent evenly, and then moisturize and maintain for 3 days;

[0050] For the second chemical stabilization treatment, ferrous sulfide particulate suspension and calcium carbonate are added to the soil. The molar ratio of the ferrous sulfide particulate addition to...

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Abstract

The invention relates to a chemical stabilization repair method of lead contaminated soil. The chemical stabilization repair method comprises the steps that (1) ferrous sulfide particle suspension liquid is prepared; (2) the lead contaminated soil is pretreated, wherein the lead contaminated soil is crushed and sieved to obtain soil with the particle size smaller than 10 cm; (3) chemical stabilization treatment of the first time is carried out, a sodium phosphate solution and a sodium chloride solution are added into the soil treated through the step (2), the water content of the soil is keptbetween 30% to 50%, and after uniform stirring and mixing, moisture preserving maintenance is carried out for 2 days to 5 days; and (4) chemical stabilization treatment of the second time is carried out, calcium carbonate and the ferrous sulfide particle suspension liquid prepared in the step (1) are added into the soil treated in the step (3), the water content of the soil is kept between 40% to60%, after uniform stirring and mixing, moisture preserving maintenance is carried out for 1 week to 3 weeks, and the repaired soil is obtained. The combined repair method is provided and is combinedwith the advantages of multiple repair agents, the treatment effect of the lead contaminated soil is improved, secondary contamination is relieved, and the TCLP leaching quantity of lead in the treated soil can be reduced to be 0.25 mg/L or below.

Description

technical field [0001] The invention belongs to the technical field of regeneration of polluted soil, and in particular relates to a method for chemically stabilizing and repairing lead-contaminated soil. Background technique [0002] Lead is one of the most toxic heavy metals to animals, plants and humans in the environment, and it is also a widely distributed, highly accumulative, non-biodegradable environmental pollutant. After lead pollutes the soil, it will enter the human body through a series of direct or indirect ways, which will have a huge impact on human health; in addition, lead has a great impact on the growth and development of plant roots. [0003] Lead in soil is a process of solid-liquid phase dynamic equilibrium, and the activity and toxicity of lead in soil also mainly depend on this equilibrium process. Most of lead in soil will be adsorbed by mineral particles in soil, and some Organic matter is complexed, and a small amount of lead exists in the form o...

Claims

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Application Information

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IPC IPC(8): B09C1/08
CPCB09C1/08
Inventor 汪军刘元元王健张晟刘坤
Owner 重庆市环境科学研究院
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