Water washing pretreatment method for making fly-ash from incineration harmless

A harmless technology for incineration of fly ash, applied in the field of environmental engineering, can solve problems such as clogging of cement kilns and hindrance of cement hydration

Inactive Publication Date: 2007-04-18
SHANGHAI UNIV
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  • Description
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  • Application Information

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Problems solved by technology

However, since a large amount of hydrochloride in fly ash will hinder the hydration of cement, and volatile heavy metals will cause clogging o

Method used

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  • Water washing pretreatment method for making fly-ash from incineration harmless
  • Water washing pretreatment method for making fly-ash from incineration harmless

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Embodiment Construction

[0012] After the fly ash is washed twice with water at a solid-to-liquid ratio of 1:8 at room temperature, chloride ions in the fly ash are removed to reduce the mass percent concentration to below 1%, and part of the heavy metals are washed out. The water for the second wash is reused as the wash water for the next batch of fly ash, reducing the water demand for the washing process.

[0013] The washing wastewater generated in the washing process is fed into CO at normal temperature and pressure. 2 , settling for half an hour to reduce the concentration of heavy metals in wastewater, then add a small amount of mixed organic flocculant, stir at room temperature, after precipitation, the concentration of ss and heavy metals in wastewater can be reduced to below the national wastewater discharge standard.

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Abstract

A process for pre-treating the fly ash generated by incineration without environmental pollution includes such steps as washing the fly ash with water for removing a lot of soluble anions and part of heavy metal ions and carbonizing and flocculating the washing sewage to make it reach draining standard.

Description

technical field [0001] The invention relates to a harmless and stabilized treatment method for hazardous waste, which belongs to the technical field of environmental engineering. In particular, it relates to a method for pretreatment of incineration gray scale and water washing. Background technique [0002] Municipal waste incineration produces a large amount of fly ash, which is equivalent to 2%-5% of the original waste mass, and contains a large amount of heavy metals and organic pollutants (such as dioxins, etc.), which is a hazardous waste clearly stipulated in the national standard (GB18485-2001) , must be processed before disposal. Current treatment methods focus on solidification stabilization, with cement being the most common stabilizer for hazardous waste. Add about 10% to 20% of the mass of fly ash into the cement, and use the strong alkalinity of the cement (pH about 12) to convert the heavy metal contained in the fly ash into a stable hydroxide, so it is very...

Claims

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Application Information

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IPC IPC(8): B09B3/00C02F1/62C02F1/52
Inventor 钱光人孙福成杨晓燕葛文莹徐霞
Owner SHANGHAI UNIV
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