Heavy metal recycling method based on municipal solid waste incineration (MSWI) fly ash

A technology of waste incineration fly ash and recovery method, which is applied in chemical instruments and methods, improvement of process efficiency, removal of solid waste, etc., can solve the problems of low added value, increased dissolution toxicity, inconvenient resource utilization, etc. Recover value, save disposal cost, harmless and reliable effect

Inactive Publication Date: 2011-10-05
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0008] The disadvantages of this technology are: 1) Heavy metals still remain in the incineration fly ash after treatment, which brings inconvenience to the subsequent resource utilization; 2) There is a problem of long-term stability when the heavy metals are stabilized by forming hydroxide precipitation. question
That is to say, the hydroxides of heavy metals are only stable under alkaline conditions. If the pH of the environment decreases, their dissolution toxicity will increase greatly; 3) In addition to achieving harmlessness, waste incineration fly ash does not form new phases, Low added value when utilized as a resource

Method used

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  • Heavy metal recycling method based on municipal solid waste incineration (MSWI) fly ash

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Embodiment 1

[0021] The toxic equivalent of dioxin in the waste incineration fly ash produced by a municipal waste incineration plant was 6.1ngTEQ / g, and the heavy metal Pb and hexavalent chromium exceeded the toxicity leaching standard by the HJ / T300 leaching method. Using the method of the present invention, in the first step, 1M (molar concentration) NaOH solution is added to the waste incineration fly ash at a liquid-solid ratio of 6 ml / g to form an ash / NaOH solution mixed system. The second step is to add hydrazine hydrate up to 0.8% of the mass of incineration fly ash. In the third step, the reactant was heated to 230° C. under constant stirring and mixing, and kept at the reaction temperature for 5 hours, and then cooled to room temperature. The fourth step is to add AlCl with a concentration of 1M (molar concentration) while continuing to stir and mix. 3 solution until the pH reaches 8.5. The fifth step is solid-liquid separation, in which the liquid is directly discarded. The s...

Embodiment 2

[0023] The toxic equivalent of dioxin in the waste incineration fly ash produced by a municipal waste incineration plant is 3.7ngTEQ / g, and the heavy metal Pb detected by the HJ / T300 leaching method exceeds the toxicity leaching standard. Adopting the method of the present invention, in the first step, 3M (molar concentration) NaOH solution is added to the waste incineration fly ash at a liquid-solid ratio of 10 ml / g to form an ash / NaOH solution mixed system. The second step is to add hydrazine carbonate up to 0.3% of the mass of incineration fly ash. In the third step, the reactant was heated to 150° C. under constant stirring and mixing, and kept at the reaction temperature for 3 hours, and then cooled to room temperature. The fourth step is to add an Al(NO3)3 solution with a concentration of 5M (molar concentration) in the state of continuous stirring and mixing until the pH reaches 11.0. The fifth step is solid-liquid separation, in which the liquid is directly discarded....

Embodiment 3

[0025] The toxic equivalent of dioxin in the waste incineration fly ash produced by a municipal waste incineration plant is 4.5ngTEQ / g, and the heavy metals Cd and Zn detected by the HJ / T300 leaching method exceed the toxicity leaching standard. Adopting the method of the present invention, the first step is to add 2M (molar concentration) NaOH solution to the waste incineration fly ash at a liquid-solid ratio of 3 ml / g to form an ash / NaOH solution mixed system. The second step is to add hydrazine carbonate to reach 1.2% of the mass of incineration fly ash. In the third step, the reactant was heated to 95° C. under constant stirring and mixing, and kept at the reaction temperature for 24 hours, and then cooled to room temperature. The fourth step is to add Al with a concentration of 2.5M (molar concentration) while continuing to stir and mix well. 2 (SO 4 ) 3 solution until the pH reaches 9.0. The fifth step is solid-liquid separation, in which the liquid is directly disca...

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Abstract

The invention relates to a heavy metal recycling method based on municipal solid waste incineration (MSWI) fly ash in the technical field of treatment for environmental protection. After an alkali solution and hydrazine substances are added to the MSWI fly ash and heated, and a water-soluble aluminum salt solution is further dripped; finally, after solid and liquid separation is conducted, heat treatment is carried out on an obtained solid phase to obtain a zeolite-active alumina compound absorbant; and the absorbant is put into sewage full of heavy metal to absorb and recycle the heavy metal. In the preparation process of the absorbant provided by the invention, dioxin in the MSWI fly ash is decomposed and removed; the MSWI fly ash is recycled as resources, and the heavy metal in the MSWI fly ash and the heavy metal in the sewage are recycled as the resources; and because the dioxin is decomposed and removed and the heavy metal is also extracted, the recycling method provided by the invention is safer and more reliable compared with the traditional treatment manner.

Description

technical field [0001] The invention relates to a method in the technical field of environmental protection treatment, in particular to a method for recovering heavy metals based on waste incineration fly ash. Background technique [0002] With the rapid development of my country's social economy, the acceleration of urbanization and the continuous improvement of people's living standards, the problem of urban waste has become increasingly prominent. Garbage disposal has become one of the major issues restricting the sustainable development of cities in our country. [0003] The basic disposal methods of MSW include landfill, incineration and composting. Among them, the incineration treatment has the advantages of small footprint, short treatment time, significant reduction (weight reduction up to 70%, volume reduction up to 90%), can kill all pathogenic microorganisms and parasite eggs, and can be recycled and utilized during the incineration process. The heat energy is b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/02B01J20/30B01J20/18C02F101/20C22B3/12B09B3/00C02F1/28
CPCY02P10/20
Inventor 吴德意谢杰李春杰
Owner SHANGHAI JIAO TONG UNIV
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