Utilizing fly ash from coal-fired power plants to improve the utilization of incineration fly ash resources and reduce toxicity

Abstract

Municipal solid waste incineration fly ash (raw ash) can be used as an admixture, but it contains much toxic substances and has a negative effect on cement performance. Co-sintering technology has the potential to solve the above problems. When Municipal solid waste incineration fly ash and fly ash from coal-fired power plants were co-sintering, the effects on the properties of incineration fly ash and used as an admixture was studied. The results showed that co-sintering increased the pozzolanic activity of municipal solid waste incineration fly ash by more than 80%, significantly increased the decomposition rate of chlorides and dioxins, and increased the amount of admixture from 1.58% of the raw ash to 11.11% of the sintered ash. When used as an admixture, the cement prepared with sintered ash reduced fineness (when the dosage was 20%, from 13.61% of the raw ash to 8.89% of the sintered ash), reduced water requirement (when the dosage was 20%, from 33.68% of the raw ash to 26.67% of the sintered ash), and increased compressive strength compared to the cement prepared with the raw ash. When the dosage was 5%, it has the highest compressive strength, which was 35.1 MPa and 53.2 MPa at 3 d and 28 d, respectively. Co-sintering with fly ash from coal-fired power plants reduced the toxicity of municipal solid waste incineration fly ash, enhanced its resource utilization in cement, and provided new ideas for the disposal and recycling of hazardous solid waste.

Keywords: Admixture; Co-sintering; Disposal and recycling; Municipal solid waste incineration fly ash; Toxicity.