Experimental Investigation and Modeling of Sulfoaluminate Cement Preparation Using Desulfurization Gypsum and Red Mud

Abstract

Desulfurization gypsum, the byproduct from wet flue gas desulfurization, and red mud, from the production of aluminum oxide, are two bulk industrial solid wastes that trigger many local environmental problems in China. This study aims to jointly utilize them. Through experimentation and modeling using FactSage, it has been found to be feasible to prepare sulfoaluminate cement using these wastes. The calcination temperature in the preparation was as low as 1250–1300 °C, and the main mineral phases of the cement clinker were 3CaO·3Al2O3, CaSO4, β-2CaO·SiO2, and 2CaO·Fe2O3. The cement clinkers tested showed excellent mechanical strength performances. This process was found to be an efficient way to consume industrial solid wastes, with the total proportion of desulfurization gypsum and red mud over 70–90% by mass in the raw materials. The sulfoaluminate cement products have outstanding cost superiority over Portland cement because of their low material costs, low material pretreatment costs, and low calcination temperature. Moreover, this technology could bring about immense environmental and social benefits in terms of waste consumption, energy conservation, and CO2 reductions. This technology has considerable prospects, and it is worth undertaking further research into its potential applications.