Investigation of the Fusion Characteristics of Ash in the Reduction of Pyrite and Phosphogypsum

Wang, Ye; Wang, Junzhe; Zhang, Zhiye; Yang, Lin; Yang, Xiushan; Zhong, Benhe; Kong, Xingjian; Wang, Xinlong

doi:10.1007/s40831-017-0138-0

Cited by 9 publications

(7 citation statements)

References 30 publications

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“…23 Simultaneously, the presence of impurities, such as phosphorus and fluorine, severely retards the setting time of the cement and reduces the early strength, causing unstable cement quality. 24,25 Currently, these problems are generally minimized by reducing the operating temperature or increasing the melting characteristics of the materials to significantly reduce the amount of liquid phase, thus avoiding crust blockage in the kiln. Simultaneously, some byproducts without strict restrictions on phosphorus and fluorine contents were adopted to solve the problem of unstable product quality.…”

Section: Introductionmentioning

confidence: 99%

“…However, this process produces liquid phases at the burning temperature of the clinker, which wraps the phosphogypsum to decrease the decomposition rate and causes ring formation in the rotary kiln . Simultaneously, the presence of impurities, such as phosphorus and fluorine, severely retards the setting time of the cement and reduces the early strength, causing unstable cement quality. , …”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Process Optimization and Mechanism Study for Sulfur Recovery from High-Silica Phosphogypsum via Carbothermal Reduction Smelting

Wang,

Hou,

et al. 2024

ACS Omega

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Phosphogypsum produced from wet-processed phosphoric acid mainly consists of calcium sulfate dihydrate, which is an important sulfur resource. The traditional sulfuric acid and cement process based on phosphogypsum suffers from unstable cement quality owing to impurities such as phosphorus and fluorine and kiln ringing caused by the low-melting phase. This study investigated sulfur recovery and value-added utilization of liquid slag from high-silica phosphogypsum via carbothermal reduction smelting. A phosphogypsum ingredient (PGI) system was constructed by adding appropriate amounts of silica, alumina, magnesium oxides, and iron oxides to meet the production requirements of slag wool. Carbothermal reduction smelting experiments suggested that the temperature and C/S molar ratio significantly affected the desulfurization rate and phase structure of the slag. More than 97.44 wt % of sulfur could be recovered with a C/S molar ratio of 0.5−0.8 at 1300 °C or above in the molten state, and the molten slag was an amorphous magnesium−calcium−aluminosilicate. The PGI desulfurization mechanism is discussed based on the phase transformation and slag microstructure evolution.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Process Optimization and Mechanism Study for Sulfur Recovery from High-Silica Phosphogypsum via Carbothermal Reduction Smelting

Wang,

Hou,

et al. 2024

ACS Omega

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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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“…At present, scholars’ research on phosphogypsum pyrolysis mostly focuses on gas as a catalyst or solids as a catalyst [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Okumura [ 27 ] studied the influence of the CO–CO 2 concentration ratio on calcium sulfate decomposition in CO-CO 2 -N 2 atmosphere and found that the regeneration of Cao from CaSO 4 was strongly dependent on the CO/CO 2 concentration ratio.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Optimization of Phosphogypsum Suspension Decomposition Conditions under Double Catalysis

Chen

2021

Materials

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Phosphogypsum (PG) is not only a solid waste discharged from the phosphate fertilizer industry, but also a valuable resource. After high-temperature heat treatment, it can be decomposed into SO2 and CaO; the former can be used to produce sulfuric acid, and the latter can be used as building materials. In this paper, the catalytic thermal decomposition conditions of phosphogypsum were optimized, and the effects of the reaction temperature, reaction atmosphere, reaction time and carbon powder content on the decomposition of phosphogypsum were studied. The research shows that the synergistic effect of carbon powder and CO reducing atmosphere can effectively reduce the decomposition temperature of phosphogypsum. According to the results of the orthogonal test under simulated suspended laboratory conditions, the factors affecting the decomposition rate of phosphogypsum are temperature, time, atmosphere and carbon powder content in turn, and the factors affecting the desulfurization rate are time, temperature, atmosphere and carbon powder content in turn. Under laboratory conditions, the highest decomposition rate and desulfurization rate of phosphogypsum are 97.73% and 97.2%, and the corresponding reaction conditions are as follows: calcination temperature is 1180 °C, calcination time is 15 min, carbon powder content is 4%, and CO concentration is 6%. The results of thermal analysis of phosphogypsum at different temperature rising rates show that the higher the temperature rising rate, the higher the initial temperature of decomposition reaction and the temperature of maximum thermal decomposition rate, but the increase in the temperature rising rate will not reduce the decomposition rate of phosphogypsum.

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Investigation of the Fusion Characteristics of Ash in the Reduction of Pyrite and Phosphogypsum

Cited by 9 publications

References 30 publications

Process Optimization and Mechanism Study for Sulfur Recovery from High-Silica Phosphogypsum via Carbothermal Reduction Smelting

Process Optimization and Mechanism Study for Sulfur Recovery from High-Silica Phosphogypsum via Carbothermal Reduction Smelting

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

Experimental Study on Optimization of Phosphogypsum Suspension Decomposition Conditions under Double Catalysis

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