Effects of alternative calcium sulphate-bearing materials on cement characteristics in vertical mill and storing

This study investigates the impact of gypsum, anhydrite and blends of them on cement and their impact on the vertical mill operation and cement storing. Mixtures of gypsum and anhydrite were prepared in the ratios: 100:0, 62.5:37.5, 50:50, 25:75 and 0:100. The results of setting time, compressive strength, soundness and moisture content showed that both gypsum and hemihydrate had the same performance in vertical cement mill as cement retarders with no noticeable change on physicomechanical properties of hardened pastes and blending both with different proportions can be used as a controller of cement setting and moisture result in improvement in cement mill operation and cement storing. In conclusion, gypsum can be replaced by anhydrite partially or completely in a vertical cement mill with no effect on cement properties. Additionally, gypsum and anhydrite blending can control moisture content in cement, improve cement storing and avoid storing problems. (C) 2021 The Authors. Published by Elsevier Ltd.