scholarly journals Iron reduction from concentrates of hydrometallurgical dressing

2021 ◽  
Vol 64 (10) ◽  
pp. 728-735
Author(s):  
I. A. Rybenko ◽  
O. I. Nokhrina ◽  
I. D. Rozhikhina ◽  
M. A. Golodova ◽  
I. E. Khodosov
Keyword(s):  
Experimental Study ◽  
Thermal Decomposition ◽  
Thermodynamic Modeling ◽  
Iron Reduction ◽  
Solid Phase ◽  
Experimental Studies ◽  
Statistical Processing ◽  
Reducing Agent ◽  
Volatile Components ◽  
Software Complex

The article presents results of theoretical and experimental studies of the processes of iron solid-phase reduction from an iron-containing concentrate obtained as a result of hydrometallurgical dressing of ferromanganese and polymetallic manganese-containing ores with coals of grades D (long-flame) and 2B (brown). The method of thermodynamic modeling using TERRA software complex was used to study the reducing properties of hydrocarbons by calculating equilibrium compositions in the temperature range of 373 - 1873 K. The authors obtained the dependences of compositions and volume of the gas phase formed as a result of the release of volatile components during heating on the temperature for the coals of the grades under consideration. As a result of thermodynamic modeling, the optimal temperatures and consumption are determined, which ensure the complete iron reduction from an iron-containing concentrate. The results of experimental studies were obtained by modern research methods using laboratory and analytical equipment, as well as methods of statistical processing. Results of the coals analysis carried out using the Setaram LabSys Evo thermal analyzer showed that the process of thermal decomposition of coals of the studied grades proceeds according to general laws. The process of thermal decomposition of long-flame coal proceeds less intensively than of brown coal. The results of an experimental study of the processes of thermal decomposition of reducing agents have shown that volumes of the gas phases, formed when coals are heated to a temperature of 1173 K in an argon atmosphere, practically coincide with the calculated values. As a result of thermodynamic modeling and experimental study, the optimal consumption of D and 2B grades of coal is determined at a temperature of 1473 K. The best reducing agent with a minimum specific consumption is long-flame coal of D grade. When determining the optimal amount of reducing agent in charge mixtures during the study of metallization processes, it was found that with an excess of reducing agent, it is possible to achieve almost complete extraction (98 - 99 %) of iron from the concentrate.

Experimental Studies and Thermodynamic Modeling of the Interaction of O2 with SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
Y. Song ◽  
F. W. Smith
Keyword(s):  
Phase Diagram ◽  
Thermal Decomposition ◽  
High Temperatures ◽  
Thermodynamic Modeling ◽  
Surface Segregation ◽  
Experimental Studies ◽  
Temperature Phase ◽  
Temperature Phase Diagram

ABSTRACTWe report on experimental studies and thermodynamic modeling of the reaction of O2 with the 4H- and 6H-SiC surfaces at high temperatures. This reaction leads to the growth of passivating SiO2 layers at high O2 pressures, etching of the surfaces at lower pressures, and enhancements of the surface segregation of carbon at still lower pressures. A pressure-temperature phase diagram for the oxidation of SiC is presented. Evidence for the thermal decomposition of the SiO2 layer on SiC is also presented.

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.

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%.

Improving the Process of High-Temperature Processing Steel-Smelting Dump Slag by Means of Experimental and Theoretical Research

2016 ◽  
Vol 843 ◽  
pp. 203-207
Author(s):  
I.V. Chumanov ◽  
Evgeny A. Trofimov ◽  
A.N. Dildin
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Experimental Research ◽  
Thermodynamic Modeling ◽  
Solid Phase ◽  
Theoretical Research ◽  
Phase Recovery ◽  
Software Complex ◽  
High Temperature Processing ◽  
Factsage Software

The aim of this work is conducting theoretical and experimental research of the processes and modes of high-temperature processing of steel slags for more complete extraction of the metal component. "FactSage" software complex (version 6.4) was used to execute the thermodynamic modeling of the processes occurring during the recovery of metals from steelmaking slags. The experimental research included experiments on solid-phase and liquid-phase recovery of slag samples at the temperatures of 1000 – 1500 °C. The results of thermodynamic modeling and experimental high-temperature slag processing allows speaking about the advisability of preliminary solid-phase recovery slag in the atmosphere of carbon monoxide with subsequent high-temperature (liquid phase) recovery to obtain separate metal fractions.

scholarly journals Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source precursor for antimony sulfide thin films

2021 ◽  
Author(s):  
Jako S. Eensalu ◽  
Kaia Tõnsuaadu ◽  
Jasper Adamson ◽  
Ilona Oja Acik ◽  
Malle Krunks
Keyword(s):  
Thin Films ◽  
Thermal Decomposition ◽  
Mass Loss ◽  
Solid Phase ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Thermal Decomposition Mechanism ◽  
Product Analysis ◽  
Gaseous Species ◽  
Single Source Precursor

AbstractThermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III) (1), a precursor for Sb2S3 thin films synthesized from an acidified aqueous solution of SbCl3 and KS2COCH2CH3, was monitored by simultaneous thermogravimetry, differential thermal analysis and evolved gas analysis via mass spectroscopy (TG/DTA-EGA-MS) measurements in dynamic Ar, and synthetic air atmospheres. 1 was identified by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) measurements, and quantified by NMR and elemental analysis. Solid intermediates and final decomposition products of 1 prepared in both atmospheres were determined by X-ray diffraction (XRD), Raman spectroscopy, and FTIR. 1 is a complex compound, where Sb is coordinated by three ethyldithiocarbonate ligands via the S atoms. The thermal degradation of 1 in Ar consists of three mass loss steps, and four mass loss steps in synthetic air. The total mass losses are 100% at 800 °C in Ar, and 66.8% at 600 °C in synthetic air, where the final product is Sb2O4. 1 melts at 85 °C, and decomposes at 90–170 °C into mainly Sb2S3, as confirmed by Raman, and an impurity phase consisting mostly of CSO 2 2− ligands. The solid-phase mineralizes fully at ≈240 °C, which permits Sb2S3 to crystallize at around 250 °C in both atmospheres. The gaseous species evolved include CS2, C2H5OH, CO, CO2, COS, H2O, SO2, and minor quantities of C2H5SH, (C2H5)2S, (C2H5)2O, and (S2COCH2CH3)2. The thermal decomposition mechanism of 1 is described with chemical reactions based on EGA-MS and solid intermediate decomposition product analysis.

scholarly journals Elucidation of the Volatilome of Packaged Spanish-Style Green Olives of Conservolea and Halkidiki Varieties Using SPME-GC/MS

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 75
Author(s):  
Alexandra Nanou ◽  
Athanasios Mallouchos ◽  
Efstathios Z. Panagou
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Acid Ethyl Ester ◽  
Volatile Components ◽  
Propanoic Acid ◽  
Qualitative Composition ◽  
Organoleptic Characteristics ◽  
Increasing Trend ◽  
Volatile Profiles ◽  
Over Time

Olives are characterized by a wide variety of volatile compounds, which are primarily products of microbial metabolism that contribute to the organoleptic characteristics of the final product and especially to its flavor. The volatilome in Spanish-style processed green olives of Conservolea and Halkidiki cultivars were analytically characterized. A solid phase micro-extraction (SPME) technique was used for the extraction of volatile components from the olive samples that were further identified and quantified by gas chromatography coupled to mass spectrometry (GC–MS). Eighty-eight (88) compounds were identified, including several aldehydes, ketones, acids, terpenes, but mainly esters and alcohols. Results showed that there were no significant differences in the qualitative composition of the volatile profiles between the two varieties. Acetic and propanoic acids, thymol, ethanol, 2-butanol, 1-propanol, ethyl acetate as well as ethyl propanoate were the most dominant compounds found in both cultivars. However, some quantitative differences were spotted between the two varieties regarding some of the identified volatile compounds. The quantity of 2-butanol was higher in the Halkidiki variety, while propanoic acid ethyl ester was found in higher amounts in the Conservolea variety. Furthermore, differences in the quantities of some volatile compounds over time were observed. Most of the identified compounds presented an increasing trend during storage.

scholarly journals Volatile Profiles of Five Variants of Abeliophyllum distichum Flowers Using Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS) Analysis

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 224
Author(s):  
Yeong-Geun Lee ◽  
Won-Sil Choi ◽  
Seung-Ok Yang ◽  
Jeon Hwang-Bo ◽  
Hyoun-Geun Kim ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Morphological Characteristics ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Components ◽  
Headspace Solid Phase Microextraction ◽  
Chromatography Mass Spectrometry ◽  
Abeliophyllum Distichum

Abeliophyllum distichum (Oleaceae), which is the only species in the monotypic genus and is grown only on the Korean peninsula, has a high scarcity value. Its five variants (white, pink, round, blue, and ivory) have different morphological characteristics in terms of the color of petals and sepals or shape of the fruits. Despite its high value, there has been no study on variant classification except in terms of their morphological characteristics. Thus, we performed a volatile component analysis of A. distichum flowers and multivariate data analyses to reveal the relationship between fragments emitted from five variants of A. distichum flowers with their morphological characteristics. As a result, 66 volatile components of this plant were identified by headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), showing unique patterns for each set of morphological characteristics, especially the color of the petals. These results suggest that morphological characteristics of each variant are related to the volatile composition.

Theoretical and experimental studies on the thermal decomposition of 1-butyl-3-methylimidazolium dibutyl phosphate

2020 ◽  
Vol 65 ◽  
pp. 104162
Author(s):  
Shunchao Li ◽  
Huichun Jiang ◽  
Min Hua ◽  
Xuhai Pan ◽  
Hangchen Li ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Studies
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