Distribution and chemical species transition behavior of chlorides in municipal solid waste incineration fly ash during the pressure-assisted sintering treatment

CO2-Assisted Water-Washing Process of Municipal Solid Waste Incineration Fly Ash for Chloride Removal

“…Nevertheless, the fly ash produced by municipal solid waste incineration (MSWI) and flue gas purification is classified as hazardous waste (code 772-002-18 in China) because of its relatively high concentration of persistent organic pollutants and high leaching rate of heavy metals. , The productions of fly ash derived from a mechanical grate furnace incineration system and fluidized bed incineration system are about 3 and 15% of MSW by weight, respectively. In 2020, over 7 million tons of MSWI fly ash was produced in China, and most of these ashes are landfilled after stabilization/solidification to reduce their leaching toxicity and fluidity. , Recently, the environmental risk of landfills has been widely concerned and even questioned for the poor long-term stability of chelated ash. , Du et al found that Pb immobilization by cement solidification failed, and both Pb and Cd immobilization by a chelator also failed after 6 years. Furthermore, the shortage of land supply even causes few new landfills to be built in some cities.…”

Controlling Role of CaClOH in the Process of Dechlorination for Municipal Solid Incineration Fly Ash Utilization

“…8,9 Compared with only IFA heating, cotreatments containing silicon aluminum were beneficial for dechlorination through heat treatment. In previous studies, the residual chlorines were 18.19−24.21 wt % for only IFA heating, 10,11 3.23−10.1 wt % for cosintering, 12,13 and 0.06−3.16 wt % for covitrification. 14,15 The residual chlorine was generally distributed in sintering products, 16 which means that dechlorination and fixed chlorine were controlled by decomposition and phase transformation of the chlorine-containing phase during thermal treatment.…”

Toward a Sustainable Municipal Solid Waste Incineration Fly-Ash Utilization Network: Integrating Hybrid Life Cycle Assessment with Multiobjective Optimization

“…Nowadays, cement kiln coprocessing (IFA to clinker) is the most widely used thermal treatment in China, although it needs high energy consumption and complex equipment. − Meanwhile, low-temperature catalytic pyrolysis and water-washing-combined processes of IFA are being practiced at the industrial scale in Zhejiang Province, China. With this nonthermal treatment technology, the degradation efficiency of polychlorinated dibenzo-p-dioxins/furans in IFA could reach about ∼99% in an inert atmosphere at 300–500 °C, , and most of the chlorides, leachable salts, and amphoteric heavy metals from IFA can be removed by the water-washing process . Importantly, finally, detoxicated IFA can be used as a raw ingredient for concrete or brick making. , Additionally, Zheng et al found that IFA treatment scenarios with washed wastewater discharge perform better in environmental credit and production cost than the scenarios with chloride recovery.…”

“…With this nonthermal treatment technology, the degradation efficiency of polychlorinated dibenzo-p-dioxins/furans in IFA could reach about ∼99% in an inert atmosphere at 300−500 °C, 22,23 and most of the chlorides, leachable salts, and amphoteric heavy metals from IFA can be removed by the water-washing process. 24 Importantly, finally, detoxicated IFA can be used as a raw ingredient for concrete or brick making. 25,26 Additionally, Zheng et al 27 found that IFA treatment scenarios with washed wastewater discharge perform better in environmental credit and production cost than the scenarios with chloride recovery.…”