Preparation of ferric-rich sulfoaluminate cement from solid wastes and characterization of its mineral formation process

Abstract

Ferric-rich sulfoaluminate cement (FR-SAC) prepared from solid waste has attracted more and more attention. However, the mineral compositions of solid waste-based FR-SAC clinkers are changeful due to the complex composition of raw materials. In this study, the influences of mineral composition and impurities in solid wastes on the mineral formation of FR-SAC clinker were investigated. The results showed that mullite in fly ash and sodium aluminosilicate in red mud did not decompose but easily reacted with other raw materials to form FR-SAC clinker. Al2(SO4)3 in galvanic sludge decomposed before the formation reaction of FR-SAC clinker. The insufficient SO2 involved in the reaction should be noted. Besides, Na2O and K2O promoted the decomposition of CaSO4 and the formation of C4AF. Most of the TiO2 formed CaTiO3, resulting in the increase of gehlenite and the decrease of C2S and CaSO4. These results can reduce the error when these solid wastes were used to prepare FR-SAC.