Effect of Fe2+/Fe3+ on high-strength ceramsite prepared by sintering geopolymers using iron ore tailings

Iron ore tailings (IOTs) and coal gasification slag (CGS) were used to prepare novel ceramsites via high-temperature sintering. The IOTs activated by NaOH form a geopolymer that was sintered at 650 °C, 850 1050 °C obtain ceramsites. formation of the confirmed characteristic peaks Si–O–T (T = Si, Al) in Fourier transform infrared spectra. X-ray diffractograms showed Fe3+ participated geopolymerization reaction, whereas Fe2+ did not; hence effect Fe2+/Fe3+ ratio investigated. This increased with increasing sintering temperature, thereby facilitating nucleation within sample. mullite–pyroxene network formed upon improved strength prepared ceramsite its structure became more compact. Specifically, cylinder compressive from 10.5 35.5 MPa after °C. Overall, this method preparing high-strength CGS can be for preparation lightweight concrete.