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Heavy metal curing agent and method for treating heavy metal compound contaminated soil by same

A compound pollution and curing agent technology, applied in the restoration of polluted soil, chemical instruments and methods, soil conditioning materials, etc., can solve the problems of unfavorable fixation, unfavorable fixation of Pb and Cu, etc., and achieve low manufacturing cost and solidification treatment cost Inexpensive, the effect of reducing the risk of toxicity

Inactive Publication Date: 2016-05-25
CHINA UNIV OF MINING & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The relatively mature research is the fixation of Pb, Cr, Cu, and Zn by lime and fly ash; the precipitation of hydroxides formed by alkaline substances and Pb, Cu, and the formation of composite salts by iron sulfate and As to achieve the fixation of Pb, Cu, and Zn in soil. and As fixation; for the pollution of Pb, Cu and As, because high pH is conducive to the fixation of Pb and Cu, but not conducive to the fixation of As, on the contrary, low pH is not conducive to the fixation of Pb and Cu, and Pb is easy to fix at low pH leaching

Method used

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  • Heavy metal curing agent and method for treating heavy metal compound contaminated soil by same
  • Heavy metal curing agent and method for treating heavy metal compound contaminated soil by same
  • Heavy metal curing agent and method for treating heavy metal compound contaminated soil by same

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preparation example Construction

[0018] Preparation of combined curing agent: calcinate shells at 600°C for 4h, peat at 200°C for 2h, pass through a #10 mesh (2mm) sieve, and the pH of shell ash is 11-13, the pH of peat ash is 7.5-8.5, According to the mass percentage of shell ash and peat ash 1:0, 2:1, 2:2, 3:1 or 3:2, add it to the soil to form a weakly alkaline soil environment.

[0019] The method for processing heavy metal compound polluted soil: directly add described combined solidifying agent in the described heavy metal compound polluted soil through pretreatment, the consumption of combined solidifying agent is 5%-25% of the mass of described heavy metal compound polluted soil, is It is lower than or equal to the sum of the maximum percentages after the combination of the two curing agents, and the moisture content is kept at 40%; the mixture after adding the combined curing agent is cured for no less than 14 days to complete the curing process.

[0020] During curing, the mixture is kept sealed dur...

Embodiment 1

[0022] Embodiment 1: The soil used for solidification comes from the former site of a resource regeneration company in a certain city, and the heavy metal Pb in the soil is determined through analysis 2+ (5796ppm), As 5+ (610ppm), Cu 2+ (760ppm) seriously exceeds the standard, as the experimental soil of this example.

[0023] A heavy metal compound polluted soil solidifying agent of the present invention, the solidifying agent comprises shells and peat (Canadian moss peat), the shells are calcined at 600°C for 4h, the peat is calcined at 200°C for 2h, and the specific components are shown in Table 1-0 , after passing #10 mesh (2mm) sieve, according to the mass ratio of 0:0, 1:0, 2:1, add in the middle of certain heavy metal composite polluted soil, obtain S1, S2, two kinds of combined curing agents, wherein S0 is without adding shell ash, peat ash and S2 only adds shell ash and does not add peat ash as the comparison of this combination curing agent invention. The mass rat...

Embodiment 2

[0030] Embodiment 2: Adopt HJ / T300-2007 method to solidify heavy metal leaching situation, table 2-1 is the leaching concentration of the heavy metal ion of the heavy metal compound polluted soil after curing 14 days in the embodiment 1 of the present invention;

[0031] Table 2-1 TCLP results

[0032]

[0033] During the curing process, the solid waste leaching toxic leaching method—acetic acid buffer solution method (HJ / T300-2007) was used to obtain leachate for the cured body after 14 days of curing.

[0034] It can be seen from the above table 2-1, according to the solid waste leaching toxicity leaching method-acetic acid buffer solution (HJ / T300-2007). The pH value of the leaching solution is reduced due to the addition of peat ash, and the pH changes in the range of 7-10 (S0-S2), which belongs to an alkaline environment and is conducive to the solidification of heavy metals. It is also known that the soil sample S2 heavy metal Pb 2+ 、As 5+ and Cu 2+ The leaching c...

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Abstract

The invention discloses a heavy metal curing agent and a method for treating heavy metal compound contaminated soil by the same, and belongs to composite curing agents and curing methods for heavy metal compound contaminated soil. The curing agent comprises, by mass, 5-15% of shell lime and 5-10% of peat ash. The method includes the steps of calcining shells at the temperature of 600 DEG C for four hours and peat at the temperature of 200 DEG C for two hours, sieving the calcined shells and peat with 10-mesh sieves (2mm) to obtain the curing agent; adding the curing agent into the heavy metal compound contaminated soil by the mass proportion of 10-25% of the heavy metal compound contaminated soil to obtain a mixture, and curing the mixture for at least 14 days, thereby completing the curing. The curing agent and the curing method have the advantages that resources for making the curing agent are wide, manufacturing cost is low and curing treatment cost is low; heavy metal leaching concentration of the heavy metal contaminated soil cured by the curing agent is much lower than the limit value of hazardous wastes identification standards on extreme conditions, toxicity of the heavy metal compound contaminated soil is reduced greatly, and curing effect thereof is perfect.

Description

technical field [0001] The invention relates to a combined curing agent for heavy metal compound polluted soil and a curing method thereof, in particular to a heavy metal curing agent and a method for treating heavy metal compound polluted soil. Background technique [0002] Soil heavy metal pollution has become one of the largest and most harmful environmental problems, and it is also a hot spot in the field of environmental research. Heavy metals are different from other pollutants. Once they enter the soil environment, they are difficult to remove. Instead, they will be enriched or transformed into more toxic compounds. In general, heavy metal pollution is not a single element pollution, but a compound pollution formed by entering the soil in the form of inorganic and organic mixtures. Heavy metals have poor mobility in soil and tend to be retained in soil. After entering the human, animal and plant body, the incubation period is long, which seriously affects human heal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08C09K17/06
CPCB09C1/08C09K17/06Y02P20/141
Inventor 李向东冯启言何小霞
Owner CHINA UNIV OF MINING & TECH
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