Method for repairing heavy metal polluted soil by chemical combined leaching

A technology of contaminated soil and combined leaching, applied in the field of soil remediation, can solve the problems of not using in-situ and ex-situ combined chemical leaching repair methods, etc., to avoid secondary pollution, low requirements and loss, and low power consumption Effect

Active Publication Date: 2013-09-25
张辉
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, the heavy metal contaminated soil remediation process has not used the combined in-situ and ex-situ chemical leaching remediation method

Method used

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  • Method for repairing heavy metal polluted soil by chemical combined leaching

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] (1) At the original site of heavy metal polluted soil, pile up 10m of the polluted soil to be treated 3 , spray chemical eluent to the heap to pre-soak the heap, the volume ratio of the chemical eluent to the polluted soil to be treated is 0.4:1, and pre-soak for 26 hours;

[0036] (2) dig up the heap after the pre-soaking is completed, and sieve;

[0037] (3) Transfer the sieved soil to the chemical reaction kettle, carry out stirring and strengthening reaction, add chemical eluent at the same time, the volume ratio of chemical eluent and polluted soil to be treated is 1.8: 1, the time of intensified reaction is 50 minutes;

[0038] (4) The soil after the strengthening reaction is dehydrated by pressure filtration to obtain repaired soil; the waste water obtained by pressure filtration is purified by adding a precipitant and a flocculant, which can be recycled. The repair results are shown in Table 1:

[0039] Table 1

[0040]

Embodiment 2

[0042] (1) At the original site of heavy metal polluted soil, pile up 10m of the polluted soil to be treated 3 , spray chemical eluent to the heap to pre-soak the heap, the volume ratio of the chemical eluent to the polluted soil to be treated is 0.6:1, pre-soak for 20 hours;

[0043] (2) dig up the heap after the pre-soaking is completed, and sieve;

[0044] (3) Transfer the sieved soil to the chemical reaction kettle, carry out stirring and strengthening reaction, add chemical eluent at the same time, the volume ratio of chemical eluent and the polluted soil to be treated is 3: 1, the time of intensified reaction for 20 minutes;

[0045] (4) The soil after the strengthening reaction is dehydrated by pressure filtration to obtain repaired soil; the waste water obtained by pressure filtration is purified by adding a precipitant and a flocculant, which can be recycled. The repair results are shown in Table 2:

[0046] Table 2

[0047]

Embodiment 3

[0049] (1) At the original site of heavy metal polluted soil, pile up 10m of the polluted soil to be treated 3 , spray chemical eluent to the heap to pre-soak the heap, the volume ratio of the chemical eluent to the polluted soil to be treated is 0.5:1, and pre-soak for 24 hours;

[0050] (2) dig up the heap after the pre-soaking is completed, and sieve;

[0051] (3) Transfer the sieved soil to the chemical reaction kettle, carry out stirring and strengthening reaction, add chemical eluent at the same time, the volume ratio of chemical eluent and the polluted soil to be treated is 2: 1, the time of intensified reaction for 30 minutes;

[0052] (4) The soil after the strengthening reaction is dehydrated by pressure filtration to obtain repaired soil; the waste water obtained by pressure filtration is purified by adding a precipitant and a flocculant, which can be recycled. The repair results are shown in Table 3:

[0053] table 3

[0054]

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Abstract

The invention discloses a method for repairing heavy metal polluted soil by chemical combined leaching. The combined leaching repairing method comprises the following steps: piling up the to-be treated polluted soil in an original field of the heavy metal polluted soil, spraying a chemical eluent to the pile with a volume ratio of the chemical eluent to the to-be treated polluted soil being 0.4-0.6:1; digging the pre-infiltrated pile and screening; transferring into a chemical reaction vessel, stirring and performing an intensifying reaction, at the same time adding the chemical eluent with a volume ratio of the chemical eluent to the to-be treated polluted soil being 1.8-3:1; and water-soil separating the soil which is subjected the intensifying reaction, respectively processing and obtaining restored soil and purified recycle water. The respective advantages of an in-situ chemical leaching method and an ex-situ chemical leaching method are combined in the repairing method, the heavy metal removing rate of the repairing method is higher than the removing effect when only one of the two leaching methods is employed, and the required repairing time is far less than the required repairing time of the in-situ chemical leaching method.

Description

technical field [0001] The invention belongs to the technical field of soil remediation, and in particular relates to a chemical combined leaching repair method for heavy metal polluted soil. Background technique [0002] With the gradual deepening of human understanding of the environment, the remediation of contaminated soil, especially heavy metal-contaminated soil, has become a hot issue in environmental science circles at home and abroad. The remediation methods of heavy metal contaminated soil can be classified into physical remediation, chemical remediation, phytoremediation, biological remediation, and electrodynamic remediation according to the remediation principle; according to the classification of soil treatment methods, they can be classified into leaching method, destruction method and immobilization method. The chemical leaching repair process of heavy metal contaminated soil is a combination of chemical method and leaching method. It is based on the injectio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08
Inventor 张辉黄新建
Owner 张辉
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