Influence of Carbon and Pyrite on Desulfurization Behavior of Red Gypsum at High Temperature

Red gypsum is generated from TiO 2 production industry by the sulfate method, which contains iron, calcium, and sulfur elements. The iron and calcium elements can be reused as iron-making raw materials, but the sulfur element in the gypsum is required to be removed as it has a harmful effect on the...

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Bibliographic Details
Published in:Journal of sustainable metallurgy 2022-03, Vol.8 (1), p.409-418
Main Authors: Ma, Xiaoling, Tan, Hongbin, Dong, Faqin, Yang, Feihua
Format: Article
Language:English
Subjects:
Calcium
Carbon
Carbon content
Decomposition
Desulfurizing
Earth and Environmental Science
Environment
Gehlenite
Gypsum
High temperature
Iron oxides
Ironmaking
Metallic Materials
Phase composition
Pyrite
Raw materials
Research Article
Sintering
Sulfur
Sustainable Development
Titanium dioxide
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Summary:Red gypsum is generated from TiO 2 production industry by the sulfate method, which contains iron, calcium, and sulfur elements. The iron and calcium elements can be reused as iron-making raw materials, but the sulfur element in the gypsum is required to be removed as it has a harmful effect on the properties of iron. Herein, the influence of carbon and pyrite on the desulfurization behavior of red gypsum is systematically investigated by high-temperature decomposition. In the absence of carbon, a small amount of anhydrite (CaSO 4 ) phase is decomposed after sintering at 1200 °C for 2 h. However, the undesirable oldhamite (CaS) phase is observed in the entombed RG/carbon50 mixture after sintering at 800 °C for 2 h, which implies that a strong reducing atmosphere can promote oldhamite to get generated. Overall, anhydrite decomposition is influenced by the carbon content, sintering temperature, and holding time. In the case of RG/carbon100 mixture, the diffraction peaks of anhydrite are not observed after sintering at 1100 °C for 2 h and 1200 °C for 0.5 h. Moreover, the main phases in RG/carbon100 mixture are found to be gehlenite (Ca 2 Al(AlSiO 7 ), magnetite (Fe 3 O 4 ), dicalcium diiron oxide (Ca 2 Fe 2 O 5 ), and lime (CaO). In addition, the phase composition of RG/carbon100 mixture is not influenced by the addition of different amounts of pyrite (FeS 2 ) after sintering at 900, 1000, and 1100 °C. Graphical Abstract
ISSN:2199-3823
2199-3831
DOI:10.1007/s40831-021-00483-8