The use of tricyclic copolymer latex (AMPS) can effectively improve the carbonation resistance of sulphoaluminate cement. This paper investigated polymer AMPS and polycarboxylic acid to modify sulphoaluminate cement materials by exploring the carbonation level of sulphoaluminate cement paste and mortar and the strength before and after carbonation. Then, the optimal dosage of polymer and polycarboxylic acid was obtained so that the carbonation resistance of sulphoaluminate cement reached the best state. The compressive strength was significantly improved by adding AMPS for sulphoaluminate cement paste and mortar. After carbonation, the strength decreased and combined with the carbonation level; it was concluded that the carbonation resistance of sulphoaluminate cement materials was the best when the optimal dosage of AMPS and polycarboxylic acid was 5% and 1.8%, respectively. Due to the addition of AMPS, the hydrated calcium aluminosilicate (C-A-S-H) and hydrated calcium silicate (C-S-H) gels, generated by the hydration of sulphoaluminate cement and the surface of unreacted cement particles, are wrapped by AMPS particles. The water is discharged through cement hydration. The polymer particles on the surface of the hydration product merge into a continuous film, which binds the cement hydration product together to form an overall network structure, penetrating the entire cement hydration phase and forming a polymer cement mortar with excellent structural sealing performance. To prevent the entry of CO2 and achieve the effect of anti-carbonation, adding polycarboxylic acid mainly improves the sample’s internal density to achieve the anti-carbonation purpose.

Preparing calcium sulfoaluminate cement (CAS) from solid waste phosphogypsum (PG) instead of natural gypsum is an effective way to utilize solid waste. In this paper, CAS clinker was successfully prepared from PG and the mineral content of calcium sulfoaluminate () in the sample was above 65%. The effects of raw material ratio, calcination temperature, and time on clinker composition were investigated. The mechanical properties of different samples were tested. The optimum ratio for preparing CAS using PG was 42.23% limestone, 17.43% PG, and 40.34% bauxite. The optimal calcination conditions are a high temperature of 1250 °C for 45 min. The 3-day compressive strengths of the laboratory-prepared CAS were all above 50 MPa. It was found that as the calcination temperature increased, the amount of produced gradually increased. Temperatures above 1300 °C resulted in the decomposition of . The calcination time did not significantly affect the mineral composition of the clinker or the strength of the cement. was observed to be rounded and hexagonal platelets with crystal sizes of 1 to 2 μm, a relatively small size that is favorable to the hydration of , as observed by SEM images. In addition, the high calcination temperature affected the particle morphology of , changing it from a well-defined polygonal structure to a molten state. The test results provide helpful information for improving PG utilization and applying PG in CAS production.

In this paper, analytically pure chemical reagents, as raw materials, were fired in barium calcium sulfoaluminate cement clinker. The effect of the iron phase on the calcination of barium calcium sulfoaluminate cement clinker was studied. The content of f-CaO in the sample was determined using the ethylene glycol method. The raw meal’s heat absorption and heat release were tested with an integrated thermal analyzer TG-DSC, and XRD and SEM measurements were used to characterize the composition and microstructure of the clinker. The results showed that the iron phase could lower the decomposition temperature of the calcium carbonate. When the calcination temperature increased, the lattice spacing of the mineral changed. The XRD pattern showed that a substitution reaction had occurred. Ba2+ replaced Ca2+ and formed a sulfoaluminate barium calcium mineral. The SEM images showed hexagonal plates or dodecahedral barium calcium sulfoaluminate minerals.