Mineralization behavior and strengthening technology of high calcium MSWI fly ash in sintering co-treatment process

Abstract

Co-processing of municipal solid waste incineration fly ash (MSWI-FA) during iron ore sintering is a potentially feasible path for harmless and resourceful utilization. In this paper, the mineralization behavior of high calcium water-washed municipal solid waste incineration fly ash (WM-FA) during iron ore sintering was studied through high temperature in-situ, diffusion couple and sintering experiments, and the corresponding regulation technology was put forward. When adding 1.0 wt.% WM-FA, the tumbler index of sinter was slightly reduced from 69.20% to 68.82%. This index dropped to 62.43% with increasing the proportion of WM-FA to 2.0 wt.%. Potential reason indicated that WM-FA showed higher soft melting temperature than that of sintering mixture, resulted in its insufficient mineralization property. By adding 20 wt.% iron ore into the WM-FA pellets, the mineralization reaction inside and outside WM-FA was significantly improved, and a large amount of CaO·Fe2O3 liquid phase was formed. The tumbler index of sinter increased from 62.43% to 68.35%. Research findings provides a certain theoretical basis for the treatment of municipal solid waste incineration fly ash in the sintering process, and is of great significance to the green and sustainable development of iron and steel industry and cities.