A novel method for preparing phosphorus building gypsum (PBG)-based building materials with low water/gypsum ratios

It is necessary to consider the dual problems of poor performance and low production efficiency that stem from the highly utilised water/gypsum ratios in the traditional preparation of phosphorus building gypsum (PBG)-based building materials. These problems cannot be easily overcome because that PBG tends to agglomerate at low water/gypsum ratios, which will hinder the hydration process and result in poor mechanical behaviour. In this study, a slurry-particle mixing system was proposed for the preparation of PBG-based building materials with homogeneous hydration at low water/gypsum ratios. More specifically, slurry-particle mixing system samples (SPMS) and pure PBG slurry samples (PPSS) with various water/gypsum ratios were prepared for comparative analysis. The results showed that the fluidity of SPMS with a low water/gypsum ratio could meet the actual production requirements. When compared with the PPSS, the SPMS had a lower water content and a higher dry density at the same water/gypsum ratios. When the water/gypsum ratio was low (e.g., 0.30), the SPMS exhibited more satisfactory moulding behaviour, greater absolutely dry compressive strength, and lower total porosity. In summary, this study presents a feasible method and viable theoretical guideline for the manufacture of PBG-based building materials with low water/gypsum ratios.