Effect of flotation phosphorus tailings on the microstructure and compressive strength of white Portland cement

The phosphate mining industry produces large amounts of tailings. Rational utilisation of phosphorus tailings (PT) is of great significance for the full exploitation of waste resources and environmental protection. In this study, PT were used as one of the raw materials to prepare white Portland cement clinker (WPCC). Various techniques were used to study the effect of PT on the mineral composition, ionic solid solution and compressive strength of the WPCC. The results showed that using PT in WPCC significantly improved the burnability of the raw material, increased the liquid phase content and promoted the formation of minerals. The addition of PT was found to stabilise α′-C₂S crystals and promoted the change of C₃S crystals in the clinker from T-type to M-type. The addition of PT had no significant effect on the decomposition temperature of calcium carbonate, the appearance temperature of the liquid phase and the formation temperature of C₃S. A PT content of 2.5% produced the highest strength of the WPCC: compared with the control group, the 3-day strength increased by 46.86% and the 28-day strength increased by 82.59%.