Influence of phosphorus impurities on the performances of calcium sulfoaluminate cement

Huang, Yongbo; Qian, Jueshi; Liu, Congzhen; Liu, Na; Yan, Shi‐Ping; Ma, Ying; Sun, Huaqiang; Yang, Fan

doi:10.1016/j.conbuildmat.2017.05.028

Cited by 54 publications

(8 citation statements)

References 31 publications

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“…The hydration reaction of ye'elimite with calcium sulfate produces ettringite, which is associated with the expansion and strength development [19]. When a large amount of ettringite produces after hardening, expansion and even cracking can occur [26]. Consequently, the dimensional stability of CSA cement should be studied.…”

Section: Dimensional Stabilitymentioning

confidence: 99%

Effect of Borax on Calcium Sulfoaluminate Cement Properties

Yan¹

2022

Ceramics - Silikaty

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This work reports the effect of borax on the performance of calcium sulfoaluminate (CSA) cements which contain different amounts of gypsum. The heat evolution, setting time, compressive strength, dimensional stability and hydration products were investigated. The results indicated that borax significantly retards the early hydration and setting time of CSA cement. The setting time is prolonged with an increased amount of additional borax. The addition of gypsum influences the early hydration of CSA cements with borax. The early strength of the mortars with borax suffers a decrease for mortars containing 5 % gypsum. The addition of borax leads to an increase in the mechanical strength of the mortars with 15 % and 20 % gypsum. An appropriate amount of borax as a retarder is beneficial to the strength development of CSA cements. The shrinkage and expansion rates of the cements with borax are limited. The presence of borax inhibits the hydration of ye'elimite and the depletion of gypsum at 1 day. The effect of borax on the ettringite formation is related to the gypsum content of the CSA cements.

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Section: Dimensional Stabilitymentioning

confidence: 99%

Effect of Borax on Calcium Sulfoaluminate Cement Properties

Yan¹

2022

Ceramics - Silikaty

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“…Although high-temperature treatment can effectively reduce the impact of some impurities on the performance of additional products, there are still some problems such as high energy consumption and unstable composition of decomposition products . At present, the high-temperature decomposition of PG is mainly studied in carbon reduction, , sulfur reduction, and admixtures. − However, the carbon reduction system is dominated by lignite, high sulfur coal, bituminous coal, coke, and graphite. − The sulfur reduction system is mainly sulfur and H 2 S. The admixture system is dominated by Al 2 O 3 , SiO 2 , and Fe 2 O 3 . However, the cost of using coke, graphite, sulfur, and admixtures is higher than that of using raw coal, and H 2 S is hazardous to humans.…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of the Activity of Anthracite on the Decomposition of Phosphogypsum

Liang

Yang

et al. 2022

Ind. Eng. Chem. Res.

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In this paper, a thermogravimetric analyzer with Fourier transform infrared spectroscopy (TG-FTIR), pyrolysis device and gas chromatography (Py-GC), and kinetic models were used to study the effect of anthracite with different activities on the decomposition of phosphogypsum (PG) and the reaction mechanism was analyzed. The results show that the decomposition rate of PG is affected by the CO partial pressure and the thickness of the decomposition product layer, and the high-activity anthracite has a high decomposition rate of PG. It mainly contains CO, CO 2 , and SO 2 in the decomposition process, while the solid products are mainly CaS, CaO, and Ca 2 SiO 4 . According to the kinetic calculation results at 800−1100 °C, it can be divided into three stages, namely, the one-dimensional diffusion model based on the solid−solid reaction, the two-dimensional diffusion based on the gas−solid reaction model, and the nucleation and growth model of CaO.

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“…Zhao et al used density functional theory (DFT) simulations to demonstrate that P atoms were more likely to replace S atoms to form phosphorusdoped ye'elimite when PG was used to produce CAS clinker [27]. Previous studies have focused on the hydration of PG-prepared CAS clinker's hydration characteristics, properties, and doping mechanism [28][29][30]. However, no systematic research has been conducted on the preparation process of CAS produced by PG, which is of great importance for industrial production.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Process Parameters of Phosphogypsum for Preparing Calcium Sulfoaluminate Cement

Zhang

Chang

et al. 2022

Buildings

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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.

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Influence of phosphorus impurities on the performances of calcium sulfoaluminate cement

Cited by 54 publications

References 31 publications

Effect of Borax on Calcium Sulfoaluminate Cement Properties

Effect of Borax on Calcium Sulfoaluminate Cement Properties

Study on the Effect of the Activity of Anthracite on the Decomposition of Phosphogypsum

Investigation of Process Parameters of Phosphogypsum for Preparing Calcium Sulfoaluminate Cement

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