Sulfoaluminate Cement and Low-Temperature Roasting Additive from Low Aluminate Raw Materials with a High Content of Silicon Oxide

Abstract

The preparation of sulfoaluminate clinkers from low-aluminate natural and technogenic raw materials that are substandard for the production of aluminate cement due to the high content of silicon oxide is considered. Raw mixtures for the synthesis of sulfoaluminate clinkers of the most approximate chemical composition from natural raw materials and from technogenic products are calculated. The technological properties, phase compositions of clinkers obtained by sintering, and hydraulic properties of sulfoaluminate clinkers and compositions with their application are compared. The presence of a sulfate component avoids the formation of clinkers in the hydraulically inert gehlenite. The presence of alkaline and other impurity compounds in the used technogenic waste reduces the synthesis temperature of sulfoaluminate clinkers by 130 degrees; changes the phase composition and properties of cement; shifts the effect of sulfation from the aluminate phase to the silicate phase. In clinkers, mainly calcium sulfoaluminate is formed from natural raw materials, and calcium sulfosilicate is formed from technogenic products. It is established that cement stone made of clinker based on natural raw materials has high strength, including in the early stages of hardening. From the considered technogenic waste, it is possible to obtain a sulfoaluminate additive of low-temperature roasting, which increases the strength characteristics of the stone from the binding composition in the early stages of hardening.