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Extractant for treating heavy metals in fly ash and method for extracting heavy metals with the extractant

A technology for extracting agents and heavy metals, applied in the field of environmental engineering, can solve the problems of toxic reagents and high cost of removal methods, and achieve the effects of low price, reduced leaching toxicity and high treatment efficiency

Inactive Publication Date: 2013-09-04
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The current various heavy metal removal methods and inventions have their own characteristics, and there are also some shortcomings: 1) mainly for the treatment of heavy metals in the soil; 2) the cost of the removal method is relatively high, and the reagents are toxic

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The extractant is prepared by mixing 50% kerosene and 50% P204 by volume evenly.

[0031]After uniformly mixing the above extractant with the fly ash of the municipal solid waste incineration plant according to the liquid-solid mass ratio of 1:1, place it in a stirrer at room temperature and stir continuously for 24 hours, then let it stand for stratification. Heavy metals in fly ash include zinc or lead. Static stratification is divided into upper and lower layers. The unsaturated extractant in the upper layer can be recycled until saturated. The saturated extractant can also be recycled after stripping with hydrochloric acid solution. The heavy metals in it are recovered in the form of a mixture. The leaching concentration of heavy metals in the lower layer of fly ash is lower than the concentration limit of the toxic equivalent of fly ash in the pollution control standard of domestic waste landfill. The leaching toxicity of heavy metals is shown in Table 1. The leach...

Embodiment 2

[0037] The extractant is prepared by mixing 80% kerosene and 20% P204 by volume evenly.

[0038] After uniformly mixing the above extractant with the fly ash of municipal solid waste incineration plant at a liquid-solid mass ratio of 5:1, place it in a stirrer at room temperature and stir continuously for 12 hours, then let it stand and separate into layers. Heavy metals in fly ash include zinc or lead. Static stratification is divided into upper and lower layers. The unsaturated extractant in the upper layer can be recycled until saturated. The saturated extractant can also be recycled after stripping with hydrochloric acid solution. The heavy metals in it are recovered in the form of a mixture. The leaching concentration of heavy metals in the fly ash in the lower layer is lower than the concentration limit of the toxic equivalent of fly ash in the pollution control standard of domestic waste landfill. The leaching toxicity of heavy metals is shown in Table 2. The leaching c...

Embodiment 3

[0043] The extractant is prepared by mixing 65% kerosene and 35% P204 by volume evenly.

[0044] After uniformly mixing the above extractant with the fly ash of municipal solid waste incineration plant at a liquid-solid mass ratio of 3:1, place it in a stirrer at room temperature and continuously stir for 20 hours, then let it stand for stratification. Heavy metals in fly ash include zinc or lead. Static stratification is divided into upper and lower layers. The unsaturated extractant in the upper layer can be recycled until saturated. The saturated extractant can also be recycled after stripping with hydrochloric acid solution. The heavy metals in it are recovered in the form of a mixture. The leaching concentration of heavy metals in the fly ash in the lower layer is lower than the concentration limit of the toxic equivalent of fly ash in the pollution control standard of domestic waste landfill. The leaching toxicity of heavy metals is shown in Table 3. The leaching concent...

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Abstract

Belonging to the technical field of environmental engineering, the invention discloses an extractant for treating heavy metals in fly ash and a method for extracting heavy metals with the extractant. The extractant of the invention comprises the following components by volume: 50-80% of kerosene and 20-50% of di(2-ethylhexyl)phosphate. The preparation method of the extractant in the invention includes the step of mixing the raw materials in the above ratio uniformly. The invention also discloses a method for extracting heavy metals with the extractant, and the method consists of the steps of: mixing the extractant for treating heavy metals in fly ash with the fly ash in a mass ratio of 1:1-5:1, placing the mixture in a stirrer at room temperature and stirring the mixture continuously for 12-24h, then leaving it for standing and layering. The extractant provided in the invention has wide source, low price and high treating efficiency, and the fly ash after extraction has zinc and lead leaching concentrations lower than the limit value prescribed by domestic waste landfill pollution control standards.

Description

technical field [0001] The invention belongs to the technical field of environmental engineering, and relates to an extractant for treating heavy metals in fly ash and a method for extracting heavy metals. Background technique [0002] Heavy metals are the primary indicators for the risk assessment of fly ash, among which mercury is the most toxic, followed by cadmium, lead, chromium and arsenic. These heavy metals can produce obvious toxic effects as long as they exist in trace amounts. The fly ash of domestic waste incineration concentrates more heavy metals in the waste. It is a recognized and legally hazardous waste and must be treated and disposed of safely. Currently, domestic waste incineration fly ash is mainly used in safe landfills, but safe landfills occupy a large area and require high processing costs. The main mineral components in fly ash are silicates and aluminosilicates, which belong to SiO 2 -Al 2 o 3 - Metal oxide system, the fly ash after harmless t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/02C22B3/38C22B13/00C22B19/00
CPCY02P10/20
Inventor 赵由才汪宝英宋玉牛静
Owner TONGJI UNIV