Composite heavy metal contaminated soil remediation agent and preparation method thereof

A technology for polluted soil and remediation agents, applied in soil conditioning materials, chemical instruments and methods, fertilizer mixtures, etc., can solve the problems of poor effect of ordinary Portland cement, large amount of chemicals added, and high remediation costs, so as to reduce the leaching of heavy metals. Concentration and environmental risks, improved gelation reaction strength, and high resource utilization effects

Inactive Publication Date: 2021-03-12
CHINA CITY ENVIRONMENT PROTECTION ENGINEERING LIMITED COMPANY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Traditional cementing materials such as cement and lime are currently the most commonly used remediation agents for heavy metal-contaminated sites, but a large number of contaminated site remediation engineering experience shows that ordinary Portland cement is not effective in remediating heavy and complex heavy metal-contaminated sites, and has poor long-term stability and The problem of high re-dissolution rate of heavy metals. In addition, cement is a typical high energy consumption and heavy pollution industry, which has a large load on the ecological environment
Aiming at the problem of complex heavy metal pollution, it is often necessary to solve the problem by compounding agents, but there are few types of agents available for compounding and industrial application, which makes the addition of more agents, large capacity expansion ratio and high repair cost when compounding and using. , poor repair effect

Method used

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  • Composite heavy metal contaminated soil remediation agent and preparation method thereof
  • Composite heavy metal contaminated soil remediation agent and preparation method thereof
  • Composite heavy metal contaminated soil remediation agent and preparation method thereof

Examples

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preparation example Construction

[0022] The preparation method of the composite heavy metal contaminated soil remediation agent, the specific process is as follows:

[0023] First, after washing the white mud with water, dry it at 40°C, ball mill it and pass it through a 100-mesh sieve; dry the metakaolin at 40°C, pass it through a ball mill and pass it through a 100-mesh sieve; Blast furnace slag was dried at 40°C, ball milled and passed through a 100-mesh sieve; the phosphogypsum was washed with water, dried at 40°C, ball-milled and passed through a 100-mesh sieve.

[0024] Among them, the heavy metal content in the metakaolin, blast furnace slag, and washed white mud and phosphogypsum is lower than the screening of the second type of construction land in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" (GB36600-2018) Values, namely copper ≤ 18000mg / kg, hexavalent chromium ≤ 5.7mg / kg, cadmium ≤ 65mg / kg, arsenic ≤ 60mg / kg, lead ≤ 800mg / kg, mercury ≤ 38mg / kg, nickel ≤ 90...

Embodiment 1

[0028] For the complex heavy metal polluted soil of a certain project, the toxic leaching is carried out according to the method of "Solid Waste Leaching Toxic Leaching Method Sulfuric Acid Nitric Acid Method" (HJ / T 299-2007). The contents of each heavy metal in the leachate are Cu: 5.63mg / L, Pb : 1.15mg / L, Zn: 4.98mg / L, As: 0.98mg / L; use the following restoration agents A1, A2, A3, A4 and agents B, C to solidify and stabilize the composite heavy metal contaminated soil.

[0029] Select white mud with a CaO content of 32%, wash the white mud with tap water, and then dry it at 40°C, use a ball mill to grind the white mud, and pass through a 100-mesh sieve; blast furnace slag with a CaO content of 28% Dry at ℃, ball mill and pass through a 100-mesh sieve; wash the phosphogypsum with tap water, then dry at 40°C, ball-mill the phosphogypsum with a ball mill, and pass through a 100-mesh sieve; metakaolin at 40°C Dried under the hood, ball milled and passed through a 100-mesh sieve....

Embodiment 2

[0034] For the complex heavy metal polluted soil of a certain project, the toxic leaching is carried out according to the method of "Solid Waste Leaching Toxic Leaching Method Sulfuric Acid Nitric Acid Method" (HJ / T 299-2007). The contents of each heavy metal in the leachate are Ni: 26.9mg / L, Pb : 14.5mg / L, Cr: 3.53mg / L. The following remediation agents A1, A2, A3 and agents B, C were used to solidify and stabilize the complex heavy metal contaminated soil.

[0035]Select white mud with a CaO content of 35%, wash the white mud with tap water, and then dry it at 40°C, use a ball mill to grind the white mud, and pass through a 100-mesh sieve; blast furnace slag with a CaO content of 32% Dry at ℃, ball mill and pass through a 100-mesh sieve; wash the phosphogypsum with tap water, then dry at 40°C, ball-mill the phosphogypsum with a ball mill, and pass through a 100-mesh sieve; metakaolin at 40°C Dried under the hood, ball milled and passed through a 100-mesh sieve. Weigh 70kg o...

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Abstract

The invention provides a composite heavy metal contaminated soil remediation agent. The composite heavy metal contaminated soil remediation agent is prepared from, by mass, 55%-70% of white mud, 15%-20% of metakaolin, 10%-15% of blast furnace slag and 5%-10% of ardealite. In addition, the invention further provides a preparation method of the composite heavy metal contaminated soil remediation agent. Industrial waste residues are adopted as main raw materials, solidification of the heavy metal contaminated soil is achieved through chemical properties and mutual activity excitation of the industrial waste residues, the characteristics of being low in cost, high in resource utilization rate, good in disposal effect and the like are achieved, the technical problems of poor effect, weak long-term stability and high heavy metal redissolution rate of composite heavy metal contaminated soil treated by an inorganic cementing material in the prior art are effectively solved, a new way is provided for resource utilization of white mud and ardealite, and agent support is provided for safe remediation and resource utilization of the composite heavy metal contaminated soil.

Description

technical field [0001] The invention belongs to the technical field of remediation of heavy metal-contaminated soil, and in particular relates to a composite heavy metal-contaminated soil remediation agent and a preparation method thereof. Background technique [0002] With the adjustment of my country's economic structure and the continuous acceleration of urbanization, a large number of industrial pollution sites have been left in my country's urban areas. According to the "National Soil Pollution Survey Announcement" issued by the Ministry of Environmental Protection in 2014, the pollution points exceeding the standard rate of heavy industrial enterprise land, industrial waste land, industrial park, solid waste centralized treatment and disposal site and mining area are 36.3% and 34.9% respectively. , 29.4%, 21.3% and 33.4%. Such sites often have many types of pollutants (Cd, Hg, As, Cu, Pb, Cr, Zn, Ni and other heavy metals coexist), high pollutant concentrations (conce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K17/08
CPCC09K17/08
Inventor 宁智张亭亭赵颖王平方园园
Owner CHINA CITY ENVIRONMENT PROTECTION ENGINEERING LIMITED COMPANY
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