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 (${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$) 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 ${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$ produced gradually increased. Temperatures above 1300 °C resulted in the decomposition of ${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$. The calcination time did not significantly affect the mineral composition of the clinker or the strength of the cement. ${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$ 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 ${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$, as observed by SEM images. In addition, the high calcination temperature affected the particle morphology of ${\mathrm{C}}_4{\mathrm{A}}_3\overline{\mathrm{S}}$, 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 innovation and entrepreneurship education, how to effectively use big data technology to improve the quality of education has become an urgent problem. In this article, the authors summarize the development of big data technology and its application background in higher education and point out the limitations of traditional education quality evaluation methods. They discuss the research status of the quality evaluation of innovation and entrepreneurship education in colleges and universities at home and abroad and the application of big data in education quality evaluation. Using the fuzzy comprehensive evaluation method, they constructed a quality evaluation model of innovation and entrepreneurship education in colleges and universities based on big data and proposed a corresponding evaluation process and index system. Finally, through empirical analysis, they verified the effectiveness and operability of the evaluation model. This research has theoretical and practical significance for improving the quality of innovation and entrepreneurship education in colleges and universities.

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.

This research presents the spatial Durbin method, which may be used to analyze the relationship between economic educational attainment and economic development in China. The method accounts for regional dependence and variety when calculating the impact of economic education on a province economic development. A pedagogical economic strategy has also taken into account how varied the education model is while implementing it. The study’s conclusions, which were based on data from Chinese provinces, showed that China’s distribution of postgraduates (PGs) was geographically autocorrelated and unstable. This work contributes to existing in two ways. It quantifies the influence of postgraduate education on technical innovation in a big, quickly rising economy. The research assesses direct and indirect impacts to comprehend postgraduate education. Overall, PG education has a big impact on technological innovation. Three geographical weighting matrices were utilized in the research study to assess spatial overflow, and it was shown that PG education in nearby provinces greatly boosted innovation. The spatial overflow effect of the economic matrix (EM) was stronger than that of the matrix adjacent to it. In both the EM and the economic-geographical matrix, the spatial overflow impact of postsecondary education was bigger than its direct influence. This research contributes to an improved considerate of the characteristics and goals of PG training in a rapidly changing market.

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.

Recycled concrete fines (RCFs) have the potential to serve as a supplementary cementitious material (SCM) after carbonation. Traditionally, carbonation of RCFs results in calcium carbonate primarily in the form of calcite, which significantly limits the development of RCFs as an SCM. In this research, a wet grinding carbonation (WGC) technique was introduced to enhance the reactivity of RCFs. The research indicates that RCFs after WGC exhibit a finer particle size and a larger specific surface area. The carbonation products include calcite with smaller grains, metastable calcium carbonate, and nanoscale silica gel and Al-Si gel. When RCF-WGC is used as an SCM in ordinary Portland cement (OPC), it significantly promotes the hydration of the cement paste, as evidenced by the advancement and increased intensity of the exothermic peaks of aluminates and silicates. RCF-WGC can significantly enhance the compressive strength of hydrated samples, particularly at early ages. Specifically, at a curing age of 1 day, the compressive strength of WGC5, WGC10, and WGC20 samples increased by 9.9%, 22.5%, and 7.7%, respectively, compared to the Ref sample (0% RCF-WGC). At a curing age of 3 days, the compressive strength of the WGC5, WGC10, and WGC20 samples showed even more significant improvements, increasing by 20.8%, 21.9%, and 11.8%, respectively. The performance enhancement of the WGC samples is attributed to the chemical reactions involving nanoscale silica gel, Al-Si gel, and calcium carbonate in the RCFs. When RCF-WGC is used as an SCM to replace 5%, 10%, and 20% of cement, it can reduce carbon emissions by 27.5 kg/t, 55 kg/t, and 110 kg/t, respectively. Large-scale application of RCFs as a high-value SCM can significantly reduce the life-cycle carbon emissions of the cement industry, contributing to the achievement of carbon peaking in China’s cement sector.