Physics of the solid-phase oxidation and reduction of metals

Рощин, В. Е.; Рощин, А. В.

doi:10.1134/s0036029515050146

Cited by 21 publications

(16 citation statements)

References 2 publications

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“…Shell of carbides on the surface of spinelide (a) and graphite (b) and the shell of a carbon-free Fe -Cr alloy on the surface of a spinelide crystal embedded in dunite (c). The work of the authors.Thereby, the results of experiments do not correspond to the concepts of the mechanism of either direct or indirect reduction, but they fully confirm the electron theory of reduction developing by the authors[11][12][13][14].The essence of this theory is in the fact that in any reduction reaction the reducing agent (solid carbon, gaseous CO, or any other) does not interact with the oxide molecules of the metal being reduced (they are not in the oxide phase), but with anions of the oxygen-type crystal lattice of oxides. The products of this interaction C + O 2− = CO + Va 2− are gas molecules (CO) and anion vacancies (Va 2− ) in an oxide lattice.…”

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confidence: 54%

Characteristics of Metal Reduction During Prereduction of Chromite types of Ore

Рощин¹,

Рощин²

2019

Kms

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confidence: 54%

Characteristics of Metal Reduction During Prereduction of Chromite types of Ore

Рощин¹,

Рощин²

2019

Kms

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“…1 - 100,00 Fe; 59 Mg,37,66 О,6,20 Fe,11,54 Mn Один такой комплекс в состоянии производить 100 - 300 тыс. т стали в год.…”

Section: обсуждение результатов исследованияunclassified

Electron Theory of Metals Reduction: Theory and Methods of Metals Extraction From Various Types of Ore

Рощин

Гамов

Рощин

et al. 2019

Izv. vysš. učebn. zaved., Čern. metall.

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The present work analyzes the existing mechanism of solid-phase metals reduction from oxides. It was shown that the existed mechanisms of reduction do not explain the diversity of the practical results leading to a generally accepted opinion that there is no single uniform reduction mechanism. This study presents the results of the solid-phase reduction of metals from lump magnetite, siderite, titanomagnetite and chromite types of ore by carbon from various deposits. The obtained results were compared with the results of reduction of chromium, silicon and aluminum by carbon from pure oxides. Change in the electrical characteristics and analysis of the processes of electron- and mass transfer under reducing conditions were performed to clarify the general theoretical concepts of reduction mechanism. It has been concluded that there is general process of transformation of the crystal lattice of oxide into the crystal lattice of metal for reduction of different metals. The positions of electron theory for solid-phase reduction of metals from crystal lattice of oxides were developed using the basic concepts of chemistry, solid state physics about imperfect crystals, quantum mechanics and character of electron distribution and transfer in metals and ionic semiconductors. The theory embraces all the known results of reduction with formation of metal on the surface of high-grade lump ore, nucleation of metal inside of the complex and low-grade types of ore and formation and sublimation of suboxides. Major ideas of the developing theory of electron reduction have been formulated on the basis of metals reduction as a result of the exchange of electrons between the reducing agent and metal cations in oxides by means of the charged anion vacancies formed on the surface and their scattering in the volume. The transformation of the cations’ ionic bond in oxides into metallic bond of the metal phase on the surface (or inside of the oxide lattice) occurs without the displacement of the cations over significant distances and thermodynamic difficulties for the formation of metallic nucleus when the charged anion vacancies merge (skipping the stage of formation of the atoms of metal). There might be no direct contact between the metal and the reducing agent in case of formation of the metal phase inside of the oxide volume. As a result, harmful impurities from the reducing agent, e.g. carbon and sulphur, do not penetrate into iron during reduction of complex and low-grade types of ore. Therefore, for the reduction of iron from such an ore, it is possible to utilize a low-quality reducing agent, e.g. steam coal. The selective solid-phase reduction of iron from lump complex ore makes it possible to obtain a metal-oxide composite material containing pure DRI and valuable oxides which are difficult for reduction, i.e. oxides of magnesium, titanium and vanadium.

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“…На сегодняшний день процессы восстановления металла в комплексных оксидах мало изучены. В работах [1][2][3][4][5][6][7] экспериментально подтверждено восстановление металла в объёме комплексных оксидов типа сидеритовой, хромовой, ильменитовой руды. Однако в таких комплексных оксидах металл концентрируется в крупные частицы разной формы, локально и в отдельных зёрнах.…”

Section: Introductionunclassified

The Phase Composition Change During Solid-Phase Carbothermal Reduction of a Complex Oxide With Low Iron Content

Зырянов¹,

Bilgenov²,

Гамов³

et al. 2018

MET

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The phase composition change as a result of the solid-phase carbothermal reduction of metal from a bulk complex oxide with a low iron content-dunite was explained. The experiments were conducted in a laboratory resistance furnace (Tamman's furnace) to study solid-phase carbothermal reduction of iron from dunite at temperature 1300 °C and for 1 hour holding time. A comparison of the results of the micro-X-ray and X-ray phase analysis of the initial dunite samples with samples after the solid-phase carbothermal reduction was performed. The phases in the initial samples of dunite were:

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Physics of the solid-phase oxidation and reduction of metals

Cited by 21 publications

References 2 publications

Characteristics of Metal Reduction During Prereduction of Chromite types of Ore

Characteristics of Metal Reduction During Prereduction of Chromite types of Ore

Electron Theory of Metals Reduction: Theory and Methods of Metals Extraction From Various Types of Ore

The Phase Composition Change During Solid-Phase Carbothermal Reduction of a Complex Oxide With Low Iron Content

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