scholarly journals ELECTRON THEORY OF METALS REDUCTION: THEORY AND METHODS OF METALS EXTRACTION FROM VARIOUS TYPES OF ORE

2019 ◽  
Vol 62 (5) ◽  
pp. 407-417 ◽  
Author(s):  
V. E. Roshchin ◽  
P. A. Gamov ◽  
A. V. Roshchin ◽  
S. P. Salikhov
Keyword(s):  
Crystal Lattice ◽  
Solid Phase ◽  
Reducing Agent ◽  
Metal Phase ◽  
Low Grade ◽  
Reduction Mechanism ◽  
Electron Theory ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Anion Vacancies

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.

scholarly journals Distribution of solid-phase reduction of iron in a layer of ilmenite concentrate

2020 ◽  
Vol 63 (2) ◽  
pp. 116-121
Author(s):  
K. I. Smirnov ◽  
P. A. Gamov ◽  
V. E. Roshchin
Keyword(s):  
Iron Reduction ◽  
Solid Phase ◽  
Point Contact ◽  
Reduction Process ◽  
Reducing Agent ◽  
Metal Phase ◽  
Contact Boundary ◽  
Silicate Phase ◽  
Ilmenite Concentrate ◽  
Reduction Of Iron

Processing of titanium-containing ores with extraction of all the major elements is an urgent task of minerals rational use. It is shown that none of the existing processing schemes allows extracting of all the major useful elements at the same time from titanium-containing iron ores, i.e. – iron, titanium and vanadium. This problem can be solved using selective extraction of these elements based on new ideas about electronic reduction mechanism. Propagation of the process of solid-phase selective reduction of iron with the powder of carbon-containing material deep into the layer of grains of ilmenite concentrate from the surface of its contact was experimentally studied. The results of determining the amount of metal phase released as it moves away from the concentrate – reducing agent contact boundary are presented. Based on the results concerning amount of precipitated metal phase, a conclusion was made about diffusion processes in a layer of concentrate grains contacting only between themselves, limiting process of iron reduction. It is shown that near the plane of contact of solid reducing agent with the layer of concentrate grains, the rate of iron reduction is higher than the rate of high iron content phase precipitation from ilmenite. In depth of ilmenite concentrate layer, process of iron reduction is preceded by formation of iron-containing silicate phase from concentrate grains, where iron is reduced earlier than in ilmenite grains. Formation of iron-containing silicate phase contributes ilmenite grains sintering. It was concluded that in the concentrate layer in contact with solid reducing agent layer in absence of contact of each ilmenite grain with solid reducing agent, the point contact of grains and presence of voids between them in the layer do not prevent propagation of reduction process in the layer of grains contacting with each other only.

Solid-Phase Reduction of Iron from Suroyam Titanomagnetite Ore during Metallization in Rotary Kiln

2019 ◽  
Vol 946 ◽  
pp. 512-516
Author(s):  
K.I. Smirnov ◽  
S.P. Salikhov ◽  
V.E. Roshchin
Keyword(s):  
Electron Microscope ◽  
Melting Point ◽  
Rotary Kiln ◽  
Solid Phase ◽  
Reduction Process ◽  
Reducing Agent ◽  
Continuous Processing ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Electron Microscope Analysis

In this work the solid-phase reduction of iron from the Suroyam titanomagnetite ore was studied during metallization in a rotary kiln. The technique of preparation of the ore and reducing agent for metallization and the process of continuous processing of materials in a rotary kiln were described in detail. For metallization the temperature was chosen 1150°C, due to low melting point of apatite from one of the components. The results of the electron microscope analysis of the initial ore and samples subjected to metallization for 1-hour reduction time were presented. The reduction of iron occurred despite absence of pores and contact with a reducing agent in the grains of titanomagnetite. Iron in the grains of titanomagnetite surrounded by apatite was reduced to wustite; whereas, iron surrounded by clinopyroxene was reduced to metallic iron. This indicated the effect of composition of the gangue materials on the reduction process.

Investigation of the process of metallized materials production from iron concentrate of hydrometallurgical enrichment of ferromanganese ores of Kuzbass

2021 ◽  
Vol 77 (6) ◽  
pp. 665-674
Author(s):  
O. I. Nokhrina ◽  
I. D. Rozhikhina ◽  
M. A. Golodova ◽  
I. E. Khodosov
Keyword(s):  
Experimental Study ◽  
Gas Phase ◽  
Solid Phase ◽  
Thermodynamic Simulation ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Isothermal Exposure ◽  
Iron Concentrate ◽  
Phase Reduction ◽  
Reduction Of Iron

Study of the processes of solid-phase reduction of iron from oxides using coals as reducing agents and the development of energy-efficient technologies for the production and use of metallized materials from concentrates obtained as a result of hydrometallurgical enrichment is an actual scientific direction in ferrous metallurgy. Theoretical studies of the processes of solidphase reduction of iron from iron-containing concentrate obtained as a result of hydrometallurgical enrichment of ferromanganese and polymetallic manganese-containing ores, by coals grades D (long-flame) and 2B (brown) were carried out by the method of thermodynamic simulation using the “Terra” software complex. The experimental study of the process of solid-phase reduction of iron from experimental mixtures was carried out in a muffle furnace SNOL 4/900 and in a resistance furnace with a graphite tubular heater (Tamman furnace). The influence of the composition and volume of gas phase, formed as a result of volatile components emission in the process of coals of two grades heating at 373–1873 K obtained, optimal temperature and consumption of coals defined, which ensure complete reducing of iron from iron-containing concentrate, compositions as well as volumes of gas phase. The influence of temperature of the isothermal exposure on the rate and degree of solid-phase reduction of iron from iron ore oxides was experimentally determined when using coals of different process grades and coke fines as reducing agents. Empirical equations of reduction degree versus time of isothermal exposure for different metallization temperatures were obtained. It is shown that the change in the degree of recovery on temperature with high accuracy was described by a linear dependence, and the change in the recovery rate on the temperature – by a power dependence. Conditions of effective metallization were determined when using iron concentrate and coals of different process grades for production of spongy metallized materials with content of Femet more than 80%, and 1.5–2.5 % C, 0.1 % S, 0.02 % P. As a result of thermodynamic simulation and experimental study of the process of iron reduction from iron concentrate, optimal consumption of coal of grades D and 2Б at temperature 1473K was determined. It was established that the best reducing agent with a minimum specific consumption is long-flame coal grade D. It was found that with an excess of reducing agent, it is possible to achieve almost complete extraction of iron from the concentrate, at the level of 98–99%.

Pyro-Metallurgical Processing of Ilmenite Concentrate with Production of Iron and Titanium Oxides

2021 ◽  
Vol 316 ◽  
pp. 385-389
Author(s):  
K.I. Smirnov ◽  
P.A. Gamov
Keyword(s):  
Crystal Lattice ◽  
Pure Iron ◽  
Solid Phase ◽  
Oxide Phase ◽  
Titanium Oxides ◽  
Laboratory Studies ◽  
Ilmenite Concentrate ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Metallurgical Processing

The main problem of processing of ores with a high content of titanium oxides is refractory slag based on TiO2, which makes it difficult to melt. The methods of processing of titanomagnetite and ilmenite ores were analyzed. It is shown that the existing scheme of processing does not meet the requirements of complex use of materials. The paper presents the results of laboratory studies on reduction of ilmenite concentrate and subsequent pyrometallurgical separation of reduction products without addition of flux or slag-forming materials. Solid-phase reduction of iron enabled to extract iron selectively from the ilmenite crystal lattice, not diluting the oxide phase with the reducing agent ash. Using the advantages of solid-phase reduction, the possibility of obtaining pure iron and slag with a high content of titanium oxides was shown.

scholarly journals Separation of ferromanganese ore components by non-contact and contact carbothermic reduction

2021 ◽  
Vol 64 (10) ◽  
pp. 761-767
Author(s):  
N. Kosdauletov ◽  
E. K. Mukhambetgaliev ◽  
V. E. Roshchin
Keyword(s):  
Solid Phase ◽  
Oxide Phase ◽  
Metallic Phase ◽  
Reducing Agent ◽  
Pure Hydrogen ◽  
Solid Carbon ◽  
Phase Reduction ◽  
Manganese Alloys ◽  
Reducing Gas ◽  
Reduction Of Iron

The possibility of joint selective solid-phase reduction of iron and phosphorus in ferromanganese ore has been experimentally confirmed. The experiments were carried out in a Tamman laboratory furnace at a temperature of 1000 °C and holding for two and five hours. The article presents results of the study of phase composition and phases' quantitative ratio of the reduction products, as well as chemical composition of the phases. It was established that reduction roasting in CO atmosphere provides a transition from oxide phase to metal phase only of iron and phosphorus. At the same time, the concentration of manganese oxide MnO increases in the ore oxide phase. The use of solid carbon as a reducing agent under the same conditions leads to transition to the metallic phase together with iron and phosphorus of a part of manganese. Based on the obtained data, it is proposed to selectively reduce iron and phosphorus at a temperature of 1000 °C with a reducing gas. Gas reduction will make it possible to use existing gas furnaces, in particular, multi-pod furnaces, for metallization of iron and phosphorus in ferromanganese ore, and natural gas, including hydrogen -enriched gas, and even pure hydrogen, as a reducing agent and energy carrier. Due to this, at the stage of ore metallization in production of manganese alloys, greenhouse gas CO2 emissions can be reduced. The results of the work can be used in the development of theoretical and technological bases for processing ferromanganese ores with a high content of phosphorus, which are not processed by existing technologies.

scholarly journals Selective reduction of iron and phosphorus from oolitic ore

2020 ◽  
Vol 63 (7) ◽  
pp. 560-567
Author(s):  
S. P. Salikhov ◽  
B. Suleimen ◽  
V. E. Roshchin
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Solid Phase ◽  
Selective Reduction ◽  
Metallic Phase ◽  
Metal Phase ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Phosphorus Reduction ◽  
Reductive Roasting

Possibility of selective solid-phase reduction of iron from oolitic ore has been experimentally confirmed. Solid phase reduction was carried out at temperatures of 850 and 1000 °C in CO atmosphere and in the mixture with solid carbon. Distribution of iron and phosphorus was investigated with scanning electron microscope. It was found that at temperature of 1000 °C minimum amount of phosphorus (up to 0.3 %) is transformed into the metallic phase at reduction by carbon monoxide. Upon reduction in mixture of ore with carbon, phosphorus content in metal phase reaches 1.0 – 1.3 % evenat temperature of 850 °C. Thermodynamic modeling of the processes occurring during reductive roasting of oolitic ore was carried out depending on temperature (1000 – 1400 K) and amount of carbon in the system. It is shown that reduction temperature and degree of phosphorus reduction vary depending on ratio of CO and CO2 in the gas phase. At temperatures below 892 °C, phosphorus is not reduced and all iron is in metal phase. With an increase in amount of carbon in the system, phosphorus appears in metal phase. With an excess of carbon in the system, all phosphorus is in metal phase at temperature of 892 °С. Thus, with a certain amount of carbon in the system and, correspondingly, with a certain ratio of CO and CO2 in gas phase, selective reduction of iron is possible without phosphorus reduction even at temperature of 1100 °С. Comparison of experimental results with results of thermodynamic calculation confirms possibility of se selective reduction of iron without phosphorus reduction only by carbon monoxide.

Influence of Temperature and Holding Time on Number and Size of Metal Particles during Solid-Phase Reduction of Iron by Carbon

2021 ◽  
Vol 316 ◽  
pp. 496-501
Author(s):  
A. Bil'genov ◽  
A.R. Tabylbaeva ◽  
P.A. Gamov
Keyword(s):  
Crystal Lattice ◽  
Solid Phase ◽  
Direct Reduction ◽  
Complex Oxide ◽  
Holding Time ◽  
Iron Particles ◽  
Experimental Conditions ◽  
Influence Of Temperature ◽  
Reduction Of Iron ◽  
Average Size

There is a lack of complete understanding of the mechanism and kinetics of reduction of metals from oxides. This paper presents results and methods of a series of experiments on direct reduction of metals by solid carbon in the form of graphite from a complex oxide with a low iron content in a laboratory muffle furnace at temperatures of 1300, 1400, 1500, 1600 °C and holding time of 1, 3, 5, 7 hours. The statistical analysis of amount and average size of reduced iron particles inside the oxide was studied. Dependence of amount and average size of the reduced iron particles on temperature and time of reduction is presented. The phenomena of iron crystals’ growth, occurring as a result of changes in the crystal lattice of oxide, was studied under experimental conditions. The influence of temperature and holding time on iron particles’ nucleation and their growth in the crystal lattice of a complex oxide were compared. Investigation of mechanism of metals’ reduction from complex oxides and influence of experimental conditions on the nucleation and growth enables to identify new patterns in the process of reduction of metals from their oxides, in general.

Statistical Analysis of Metal Particles Forming during Reduction of Oxides with Low Iron Content

2018 ◽  
Vol 284 ◽  
pp. 673-678 ◽  
Author(s):  
A.S. Bilgenov ◽  
Yu. Kapelyushin ◽  
P.A. Gamov
Keyword(s):  
Solid Phase ◽  
Metallurgical Industry ◽  
Metal Particles ◽  
Low Grade ◽  
State Reduction ◽  
Reduction Behavior ◽  
Phase Reduction ◽  
Ore Minerals ◽  
Average Size ◽  
Solid State Reduction

Metallurgical Industry slowly moves towards wider utilization of complex ore minerals. Reduction behavior of complex crystalline structures can hardly be interpreted applying kinetic modeling adopted for pure oxides. The quantitative mathematical analysis of the metal particles forming during solid state reduction of a complex mineral has been suggested. The analysis with 95% reliability showed that during solid phase reduction of dunite at 1300 °C for 60 min about 360 particles with an average size about 0.62 mm formed from the total area S = 20880 mm. Such an approach could be useful for development of sophisticated kinetic models applied for reduction of a low-grade complex ore.

Solid-Phase Reduction and Separation of Iron and Phosphorus from Manganese Oxides in Ferromanganese Ore

2021 ◽  
Vol 410 ◽  
pp. 281-286
Author(s):  
Nurlybay K. Kosdauletov ◽  
Vasiliy R. Roshchin
Keyword(s):  
Manganese Oxides ◽  
Solid Phase ◽  
Oxide Phase ◽  
Metallic Phase ◽  
Scanning Microscope ◽  
X Ray ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Reducing Roasting ◽  
Electron Scanning Microscope

The possibility of joint solid-phase reduction of iron and phosphorus from ferromanganese ore has been experimentally confirmed. Solid-phase reduction was performed at a temperature of 1000°C and exposure time of 2-5 hours, in a CO atmosphere, also produced the separation of the reduction products by melting. The distribution of iron and phosphorus was studied using an electron scanning microscope. The phase analysis of the samples was studied using a Rigaku Ultima IV X-ray diffractometer. The results were processed using the "Match" software. Reducing roasting in a CO atmosphere provides a transition from the oxide phase to the metallic phase of only iron and phosphorus without loss of manganese, thus increasing the concentration of MnO oxide in the residual oxide phase of the ore.

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