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Reduction Kinetics of Hematite Powder in Hydrogen Atmosphere at Moderate Temperatures

Abstract

Hydrogen has received much attention in the development of direct reduction of iron ores because hydrogen metallurgy is one of the effective methods to reduce CO2 emission in the iron and steel industry. In this study, the kinetic mechanism of reduction of hematite particles was studied in a hydrogen atmosphere. The phases and morphological transformation of hematite during the reduction were characterized using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. It was found that porous magnetite was formed, and the particles were degraded during the reduction. Finally, sintering of the reduced iron and wüstite retarded the reductive progress. The average activation energy was extracted to be 86.1 kJ/mol and 79.1 kJ/mol according to Flynn-Wall-Ozawa (FWO) and Starink methods, respectively. The reaction fraction dependent values of activation energy were suggested to be the result of multi-stage reactions during the reduction process. Furthermore, the variation of activation energy value was smoothed after heat treatment of hematite particles.

Funding source: Thanks are given to the financial supports from the National Key R&D Program of China (2017YFB0603800 & 2017YFB0603805), National Natural Science Foundation of China (51604046, 51674053), Fundamental and Frontier Research Project of Chongqing (cstc2017jcyjAX0322), Natural Science Foundation of Hebei Province (No. E2018209266) and Natural Science Foundation of Tangshan city (No. 17110208a).
Related subjects: Applications & Pathways
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/content/journal4245
2018-09-23
2023-01-27
http://instance.metastore.ingenta.com/content/journal4245
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