Effect of additives on melting temperature and energy consumption of municipal solid waste incineration fly ash

Abstract

This paper presents the melting temperature (MT) and energy consumption (EC) of model municipal solid waste incineration (MSWI) fly ash (FA) under the influence of calcium oxide (CaO), silicon dioxide (SiO2), aluminium oxide (Al2O3) and boron oxide (B2O3) based on thermochemistry simulations. Nine different base-to-acid ratios (B/A) of raw FA have been explored. The results show that the effects of CaO, SiO2 and Al2O3 vary for different B/A ranges. SiO2 and Al2O3 play positive roles in decreasing the MT and EC of FA4–FA9 with high B/A (B/A: 2.61, 4.48, 6.43, 6.90, 8.32, 8.82). CaO plays a positive role in decreasing the MT and EC of FA1 and FA2 with low B/A (B/A: 0.22, 0.43). In FA3 (B/A: 1.22), the MT and EC of FA cannot be reduced by adding CaO, SiO2 and Al2O3. The addition of B2O3 cannot only further reduce the MT of FA, but also reduce the EC. B2O3 and SiO2 can work together to reduce the MT and EC when B/A is high (2.61–8.82), and SiO2 and B2O3 can be introduced into the FA by adding waste glass and other boron containing waste to realize the coordinated disposal of waste.

Municipal Solid Waste Incineration Ash-Incorporated Concrete: One Step towards Environmental Justice

“…Vitrification is a process to melt the MSWI FA residue with the addition of other solid wastes or additives (also known as flux agents). The addition of basic oxides (e.g., Na 2 O, K 2 O, MgO, and CaO) or solid wastes with high content of basic oxides lowers the melting point of the ash residue [121,122], thus reducing the energy consumption of thermal pretreatment. Although flux agents lower the cost of fuel consumption, the trade-off of melting temperature and cost of flux agents must be considered (e.g., B 2 O 3 is relatively expensive).…”

Synergistic effect of polyvinyl chloride and coal ash on thermal separation of heavy metals from MSWI fly ash through molten salt process

“…However, fly ash (FA) is a second pollutant produced from MSWI, and it contains a large number of heavy metals, salts, dioxins and other harmful substances, which are classified as hazardous waste and need to be treated safely (Chen et al, 2019; Ohbuchi et al, 2020; Vehlow et al, 2006). The treatment of FA is primarily safe landfill after solidification, including cement solidification (Tang et al, 2020; Yakubbu et al, 2018a), melting solidification (Alhadj-Mallah et al, 2015; Gao et al, 2021) and chemical stabilization (Liu et al, 2016; Wang et al, 2015). Due to the shortage of land resources and the increasing availability value of FA, FA disposal technology has been mainly focussed on resources recovery technology in recent years.…”