National University of Science and Technology MISIS, Moscow, Russia

N. A. Maslennikov, Assistant, Dept. of Minerals and Technogenic Raw Materials Beneficiation and Processing, e-mail: masl.nik2000@gmail.com
Yu. V. Konyukhov, Dr. Eng., Head of the Dept. of Minerals and Technogenic Raw Materials Beneficiation and Processing, e-mail: ykonukhov@misis.ru
I. N. Burmistrov, Dr. Eng., Leading Expert, Dept. of Functional Nanosystems and High-Temperature Materials, e-mail: burmistrov.in@misis.ru

University of Science and Technology Beijing, Beijing, China

Rita Khanna, Ph. D., Prof., School of Metallurgical and Ecological Engineering, e-mail: rita.khanna66@gmail.com

Tashkent Branch of National Research University MPEI, Tashkent, Uzbekistan

M. V. Kravchenko, Cand. Eng., Director, e-mail: mail: Kravchenkomv@mpei.ru

Hydrogen reduction technology with zero greenhouse gas emissions is a promising alternative to the carbothermic process implemented according to the classical scheme: a blast furnace converter. This study reports investigations on the kinetics of hematite ore reduction by hydrogen in a stationary and vortex layer. The vortex layer apparatus is a magnetic inductor in which a resistance furnace with a stainless-steel flow reactor is inserted. The reactor is loaded with reduceable material and magnetic needles. Under the influence of a magnetic field, the needles move and interact with the material, each other and the walls of the chamber. Three ore specimens from Russian and Chinese deposits with significant differences in morphology and composition were investigated. Ore A (Russian origin) contained spherical particles with low iron content but high silica levels, whereas ores B and C (Chinese origin) contained needle like particles high in iron content and low silica levels. Pure hematite powder was used as a reference sample. The transformation of hematite into magnetite and iron was studied in a hydrogen flow at 375 °C and 400°C under conditions of a stationary and vortex layer. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry were used to study the properties of the initial materials, intermediate and final products. The calculation of the rate constants was carried out using Mekewan model. The paper shows that the process of reducing iron ores with hydrogen proceeds more intensively in a stationary layer, while the reduction rate of pure Fe₂O₃ is higher in a vortex layer. The results obtained indicate the critical influence of impurities (such as silicon dioxide) and the polydispersity of the initial powder on the kinetics of hydrogen reduction.

The research was supported by a grant from the Russian Science Foundation (project No. 24-29-00672).

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