Curing agent for heavy metal contaminated soil restoration and heavy metal contaminated soil restoration method

A technology of contaminated soil and curing agent, which is applied in the restoration of contaminated soil, chemical instruments and methods, soil conditioning materials, etc., can solve the problems of long repair period, poor long-term repair effect, large soil damage, etc., and achieve solidification of heavy metals , Reduce the effect of leaching toxicity

Inactive Publication Date: 2013-01-16
BEIJING CHINA SCI GENERAL ENERGY & ENVIRONMENT CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the current inorganic materials have disadvantages such as large amount of use,

Method used

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  • Curing agent for heavy metal contaminated soil restoration and heavy metal contaminated soil restoration method
  • Curing agent for heavy metal contaminated soil restoration and heavy metal contaminated soil restoration method
  • Curing agent for heavy metal contaminated soil restoration and heavy metal contaminated soil restoration method

Examples

Experimental program
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Effect test

no. 1 example

[0033] In one embodiment of the present invention, the main component of the curing agent for remediation of heavy metal contaminated soil is sulphoaluminate cement.

[0034] When the curing agent is used to repair heavy metal contaminated soil, the following two steps are included: step 1, use sulfoaluminate cement to prepare the curing agent, that is, repair powder; step 2, combine the heavy metal contaminated soil with the repair The powders are mixed, and water is sprayed during the mixing process.

[0035] The main reaction that occurs during curing is the hydration reaction of sulphoaluminate cement

[0036] 3CaO·Al 2 o 3 ·CaSO 4 +nH 2 O→3CaO·Al 2 o 3 ·CaSO 4 ·(30-32)H 2 O+

[0037] The hydration rate of sulphoaluminate cement is very fast, and the hydration is close to completion within 24 hours, so the hydration reaction of sulphoaluminate cement is mainly at the beginning of the reaction.

[0038] Note that sulfoaluminate cement powder should be absolutely w...

no. 2 example

[0041] In another embodiment of the present invention, the curing agent for remediation of heavy metal-contaminated soil may also contain a composition containing active silica in addition to sulphoaluminate cement powder. Here, the composition containing active silica may be silica fume, fly ash or pozzolan. For example, in this embodiment, silica fume can be selected to be added.

[0042] Through the addition of silica fume, the curing effect of heavy metals is strengthened, especially for the long-term effectiveness of the restoration. It can enhance the solidification effect of heavy metals and ensure that heavy metals in soil will not be reactivated under environmental conditions after remediation and pollute the environment.

[0043] The specific reaction mechanism is described as follows, and the main reactions that take place include the following two:

[0044] The first is the hydration reaction of sulphoaluminate cement

[0045] 3CaO·Al 2 o 3 ·CaSO 4 +nH 2 O→3Ca...

no. 3 example

[0057] A preferred embodiment of the present invention is described below.

[0058] In this embodiment, on the basis of the second embodiment, quicklime powder and glucose as a surfactant can be added to the solidifying agent for remediation of heavy metal-contaminated soil. That is, the solidifying agent for remediation of heavy metal contaminated soil contains sulfoaluminate cement, silica fume, quicklime and glucose.

[0059] In specific implementation, the mass percentage of sulfoaluminate cement in the curing agent is preferably controlled to be 40%-60%, the mass percentage of silica fume in the curing agent is preferably controlled to be 30%-45%, and the mass percentage of quicklime in the curing agent The mass percentage is preferably controlled to be 5%-15%. But in fact, if the mass percentage content falls outside the above-mentioned range, the curing agent mixed with the three can also solidify the soil polluted by heavy metals, but the effect is not as good as that...

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Abstract

The invention discloses a curing agent for heavy metal contaminated soil restoration and a heavy metal contaminated soil restoration method. The curing agent for the heavy metal contaminated soil restoration comprises sulphoaluminate cement, and composition containing active silica and quick lime can be further added in the curing agent. After the sulphoaluminate cement is mixed with soil contaminated by heavy metal, firstly calcium sulphoaluminate in the sulphoaluminate cement is reacted with water to form monosulfate calcium hydroaluminosulfate, then heavy metal compound chemical bond is broken, heavy metal and atoms in ettringite are subjected to recombination of the chemical bond, metal atoms are constrained in a crystal lattice in space and not prone to be precipitated, thereby the purpose of curing heavy metal can be achieved, and the leaching toxicity of the heavy metal is reduced. A test proves that an obvious restorative effect can be achieved after the sulphoaluminate cement is used for 24 hours, namely after restoration, the soil leaching concentration is reduced and maintained within specified requirements, and the heavy metal can be effectively cured.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a curing agent for remediation of heavy metal polluted soil and a method for remediation of heavy metal polluted soil. Background technique [0002] Heavy metals generally refer to about 60 elements with a specific gravity above 4.0 or about 45 elements with a specific gravity above 5.0. Heavy metals in environmental pollution research mainly refer to elements with significant biological toxicity such as Pb, Cd, Hg, Cr, and metalloid As, and also include heavy metals such as Zn, Cu, Co, Ni, and Sn with certain toxicity. Some heavy metal elements are essential elements for the human body and other organisms, but their concentration exceeds a certain range will cause poisoning. [0003] Soil heavy metal pollution refers to the phenomenon that human activities introduce heavy metals into the soil, causing the content of heavy metals in the soil to be significantly ...

Claims

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Application Information

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IPC IPC(8): C09K17/10C09K17/48B09C1/08
Inventor 张亮吕溥刘向坤赵虎军
Owner BEIJING CHINA SCI GENERAL ENERGY & ENVIRONMENT CO LTD
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