A method for synchronously realizing the detoxification of incineration fly ash and the reduction and solidification of chromium slag

Abstract

The invention discloses a method for synchronously achieving incineration fly ash detoxification and chromium slag reduction curing. The method includes the following steps that (1), incineration flyash and tuff are weighed, mixed to be uniform and ground, and gelatinized powder is obtained; (2), sodium hydroxide and sodium silicate are weighed, mixed to be uniform and ground, and an alkali activator is obtained; (3), sodium persulfate and sodium oxalate are weighed, mixed to be uniform and ground, and a reductive detoxification inducer is obtained; (4), chromium slag, the gelatinized powder,the alkali activator and the reductive detoxification inducer are weighed, mixed to be uniform and ground, and fly ash and chromium slag powder is obtained; (5), the fly ash and chromium slag powderis weighed and dissolved in water, the materials are mixed to be uniform, and fly ash and chromium slag slurry is obtained; (6), the fly ash and chromium slag slurry is sealed, activated through microwaves, cooled and put in a die to be cured. The leaching concentrations of multiple heavy metals and dioxin in the fly ash and a chromium heavy metal in the chromium slag are all lower than the entrance limiting value of a municipal solid waste landfill. Treated cured bodies have high acid resistance and high constraint capacity for heavy metal inorganic pollutants and organic pollutants.

Description

technical field [0001] The invention relates to a treatment method for hazardous solid waste, in particular to a method for synchronously realizing detoxification of incineration fly ash and reduction and solidification of chromium slag. Background technique [0002] Municipal solid waste incineration fly ash contains heavy metal inorganic pollutants with high leaching concentration and highly toxic dioxin organic pollutants. Chromium slag contains hexavalent chromium heavy metal ions, which are all listed in the "National Hazardous Waste List". Garbage incineration If fly ash and chromium slag are directly landfilled without specific treatment, the released heavy metal ions and organic pollutants will pollute water quality and soil, thereby seriously endangering human health. According to the "Pollution Control Standards for Domestic Garbage Landfill Sites" (GB16889-2008), the content of heavy metal pollutants and organic pollutants must be lower than a certain standard bef...

AI Technical Summary

Problems solved by technology

High-temperature sintering has problems such as high energy consumption, high technical requirements for tail gas disposal, poor product quality, and secondary treatment of slag.

Chemical stabilization has problems such as large amount of chemical stabilizer, sensitivity of stabilized fly ash to environmental changes, difficulty in simultaneously stabilizing organic pollutants and inorganic pollutants, etc.

Chemical leaching not only consumes a large amount of eluent, but also easily produces secondary pollution in the process of solid-liquid separation and leaching waste disposal.

Physical packaging has problems such as mixing of coating layer and fly ash, large amount of asphalt, and difficulty in long-term storage of fly ash in landfill environment after disposal.

Electric removal technology has problems such as continuous water filling during operation, high power consumption, and uneven pollutant enrichment areas.

The cost of curing technology is relatively low, the raw materials used are easy to obtain, and it has a good binding force on the activity of heavy metal substances in fly ash, and the technology is mature and easy to manage. However, the strength of the existing technology after curing is not high, and the performance of curing heavy metals Relatively poor, the acid leaching resistance of the cured product is weak, and the cured body has weak binding to organic pollutants

[0004] Reduction-solidification integration is a common method to deal with chromium slag. At present, the most widely used reducing agents are zero-valent iron and ferrous ions. However, during the reduction process, the ferric ions produced will significantly reduce the solidification of chromium slag in the later stage. The acid resistance increases the leaching toxicity and environmental sensitivity of the cured body

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