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Method for pretreating fly ash of domestic refuse incineration through cooperative disposal of cement kilns

A domestic waste incineration and co-processing technology, applied in water/sludge/sewage treatment, water/sewage treatment, neutralized water/sewage treatment, etc. Control and other issues, to achieve the effect of shortening the process cycle, low cost and reliable operation

Inactive Publication Date: 2010-06-30
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Our previously submitted invention "method for recycling domestic waste incineration fly ash in cement kiln" (application number 200710177811.9) provides a method for recycling domestic waste incineration fly ash in cement kiln, including water washing-carbonation pretreatment and There are two stages of calcination in the cement kiln. In view of the high pH in the washing liquid and the characteristics that the dissolution of heavy metals is difficult to meet the standard, the patent uses CO 2 Neutralize alkalinity and precipitate heavy metals. The moisture content of the dehydration filter cake is 25-45%. However, in practical applications, the use of waste gas from the kiln tail requires a large amount of construction work, high investment, and it is difficult to control the pH in actual operation, and the precipitation effect of heavy metals is unstable.

Method used

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  • Method for pretreating fly ash of domestic refuse incineration through cooperative disposal of cement kilns
  • Method for pretreating fly ash of domestic refuse incineration through cooperative disposal of cement kilns
  • Method for pretreating fly ash of domestic refuse incineration through cooperative disposal of cement kilns

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Embodiment 1

[0022] Embodiment 1 (concrete technique such as figure 1 shown)

[0023] Incineration fly ash of a municipal solid waste incineration plant, the content of Cl element is 17.96wt%, the content of Zn element is 0.54wt%, the content of Pb element is 0.23wt%, the content of Sn element is 0.12wt%, and the content of Cu element is 0.09wt%. , Cr element content is 0.09wt%.

[0024] Mix each batch of 1t incineration fly ash and water in the water washing equipment according to the weight ratio of water: ash = 4:1, stir for 10 minutes, let it stand for half an hour, then extract the supernatant into the neutralization tank, slowly add the concentration It is 20% industrial sulfuric acid, and it is stirred while adding, and the pH meter monitors and controls the sulfuric acid dripping amount in real time. After the pH reaches 6-9, transfer the solution to the chelation tank, add 1 wt% DTC chelating agent based on the fly ash mass according to the preliminary experiment, stir rapidly w...

Embodiment 2

[0025] Embodiment 2 (concrete technique is as figure 2 shown)

[0026] Incineration fly ash of a municipal solid waste incineration plant, the content of Cl element is 17.96wt%, the content of Zn element is 0.54wt%, the content of Pb element is 0.23wt%, the content of Sn element is 0.12wt%, and the content of Cu element is 0.09wt%. , Cr element content is 0.09wt%.

[0027]Incineration fly ash and water are mixed in water washing equipment according to the weight ratio of water: ash = 15: 1, stirred for 10 minutes, and transferred to the vacuum belt filter press as a whole, and the water content of the press filter cake is reduced to 22.1wt%. The amount of chlorine is reduced to 0.86wt%, and it can be mixed with raw meal in an amount of 4wt%, and then directly put into kiln for calcination. Add DTC chelating agent with 1.5wt% fly ash mass according to the preliminary experiment, stir rapidly while adding, and transfer to the flocculation tank as a whole after stirring for 15...

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Abstract

The invention discloses a method for pretreating fly ash of domestic refuse incineration through cooperative disposal of cement kilns, which belongs to the technical field of solid waste treatment and disposal. The method comprises a fly-ash washing-dechlorination stage, a washed-ash dehydration stage, a supernatant treatment stage and a kiln-entering calcination stage, wherein sulfuric acid serving as neutralizer is added to supernatant or removed filtrate in order to neutralize the supernatant or the removed filtrate and allows pH to reach a range between 6 and 9, and then dithiocarbamate-type derivatives serving as a heavy metal chelating agent and a polyacrylamide flocculating agent are added in turn to guarantee the precipitation effect of heavy metal ions. Sulfuric acid neutralization and heavy metal precipitation are performed on eluate to ensure that washing liquid can reach discharge standards. The method utilized to treat fly ash has the advantages of saving raw materials of the cement industry, effectively fixing heavy metal, thoroughly burning down dioxin, disposing of fly ash safely, economically and conveniently and achieving environmental, economic and social benefits.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment and disposal, and in particular relates to a pretreatment method for co-processing of domestic waste incineration fly ash in a cement kiln. Background technique [0002] In recent years, with the rapid development of waste incineration in our country, as an inevitable product of waste incineration, the output of fly ash is also increasing year by year. At the end of 2008, the incineration and treatment capacity of municipal solid waste in my country was 68540t / d, of which the incineration capacity of grate furnace and fluidized bed was 43970t / d and 24570t / d respectively, and the amount of fly ash produced by grate furnace was 1 / 2 of the amount of waste entering the furnace. 3-5%, the output of fluidized bed fly ash is 15-20% of the furnace waste, then the daily output of fly ash is 5004.6-7112.5t, and the annual output is 1.65-2.35 million tons. Domestic waste incineration fly ash ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00C04B7/26C02F1/62C02F1/66
CPCY02P40/10
Inventor 金宜英张俊丽凌永生李欢王雷聂永丰
Owner TSINGHUA UNIV
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