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Biochar has been extensively used in ferrous metallurgy in recent years as it has comparable metallurgical properties to coke and coal, showing great potential for reduction of the production cost of iron and steel with enhanced quality and for promotion of environmental protection. This article reviewed the main applications of biochar in the iron and steel industry, including its use in coking,...
A process is being developed to recycle zinc-bearing metallurgical dust by reductive sintering. In the present work, the reaction behavior of zinc and iron oxides was studied in different conditions in CO–CO2 atmosphere, to understand the processes involved and determine the optimal conditions. The results showed that dezincification started to become significant when the coke addition was 9.0 wt...
The dual effect of sodium-salt-assisted reductive roasting for iron recovery and chromium enrichment from lateritic iron ore was investigated. Iron oxides were reduced to metallic iron through reductive roasting, while Al- and Si-bearing components were transformed to sodium aluminosilicate and/or diaoyudaoite. Thus, direct reduced iron (DRI) was recovered by magnetic separation, while Cr(III) element...
The reduction process of chromium-bearing vanadium–titanium sinter (CVTS) was studied under the simulated conditions of a blast furnace at 1173 K, and the kinetics and mineral phases were analyzed. The reduction kinetics of CVTS at different reduction times was studied using a shrinking unreacted core model. The microstructure, mineral phase and variations of the sinter during reduction were observed...
Preparation of refractory materials from ferronickel slag by sintering over a broad temperature range (1200°C to 1500°C) with addition of sintered magnesia was explored. The thermodynamic calculations indicated that the amounts of newly generated high-melting-point forsterite and spinel phases increase with increasing temperature. The experimental analysis demonstrated that elevating the sintering...
In our previous study, an intermediate material enriched with multiple rare earth elements (REEs, e.g., La2O3, Ce2O3, Sc2O3, and Y2O3) and TiO2 was obtained after removing iron, silica, and alumina from bauxite residues. For valorization of this valuable intermediate material, the selective leaching and separation of REEs and TiO2 by phosphoric acid leaching was investigated. Approximately 90% of...
A technical route has been proposed to upgrade diasporic bauxite ores for iron and alumina enrichment based on reductive roasting, followed by magnetic separation and alkaline leaching. The thermodynamic analysis revealed that by reductive roasting of the bauxite ore at 980–1100°C, hematite in the ore is transformed to magnetite and kaolinite is converted into γ-Al2O3 and SiO2 (amorphous). Meanwhile,...
The melting behavior of titanium-bearing electric furnace slag is a key factor for effective smelting of vanadium titanomagnetite in electric furnaces. The melting behavior of synthetically produced CaO-SiO2-MgO-Al2O3-TiO2 slags with different TiO2 contents (48 wt.% to 54 wt.%), CaO/SiO2 mass ratios (0.8 to 1.4), and MgO contents (8 wt.% to 14 wt.%) was experimentally investigated in this study. The...
The suppression of titanium oxide reduction enables both successful separation of iron from slag and smooth production operations for the smelting of vanadium titanomagnetite. This study investigates the distribution behavior of titanium between the hot metal and enriched titanium slag during the electric furnace smelting of vanadium titanomagnetite metallized pellets. Activity calculations indicate...
The behavior of silicon during smelting of vanadium titanomagnetite metallized pellets in an electric furnace has been investigated thermodynamically and experimentally. Thermodynamic calculations indicated that the activities of free oxygen ion and silicate increase with increasing CaO and MgO content in the titanium slag, whereas silica activity decreases as CaO and MgO increase. High-temperature...
Reduction and smelting of the vanadium titanomagnetite metallized pellets have been experimentally investigated in this study. By using the high-temperature smelting, rapid quenching, and electron probe x-ray microanalysis (EPMA) technique, the effects of basicity, reaction time, and graphite reductant amount were investigated. The vanadium contents in iron alloys increase with increasing basicity,...
Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium–vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid–solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined...
The effects of borax (sodium borate) on the enhancement reduction of pre-oxidized Panzhihua ilmenite were investigated. The effects of borax on the mineral phase transformation, microstructures, crystal cell parameter, melting point and Mg distribution were studied to reveal the mechanism of enhancement reduction. Under the constant reduction conditions, the borax could reduce the reduction activation...
The proven global tin reserves were reported to be approximately 4.7 million tons (Mts) in 2016, and among these resources, only approximately 2.2 Mts can be recovered economically. The original tin deposits will be exhausted in several years, therefore, tin-bearing secondary resources, such as tin alloy, tin anode slime, e-wastes, tin slag and tin-bearing tailings, will become the primary source...
Methane and hydrogen reduction has emerged as promising technology for clean and efficient metallurgy. To understand the reduction process of MnO2 by CH4-H2 gas mixture, the effects of various CH4/(CH4 + H2) molar ratios (0–1) and temperatures (1100°C–1250°C) on the reduction of pure MnO2 were researched. Characterization of the solid carbon derived from the decomposition of CH4 gas was also determined...
As an important secondary resource with abundant platinum group metals (PGMs), spent catalysts demand recycling for both economic and environmental benefits. This article reviews the main pyrometallurgical processes for PGM recovery from spent catalysts. Existing processes, including smelting, vaporization, and sintering processes, are discussed based in part on a review of the physiochemical characteristics...
The complicated reduction behaviors of iron, vanadium and titanium oxides must be accurately controlled for the successful smelting of vanadium titanomagnetite. The aim of this study is to investigate the effects of the binary basicity, MgO content, smelting temperature, duration and reductants on the reduction of iron, vanadium and titanium oxides during the electric furnace smelting of vanadium...
In this study, extraction of aluminum-, iron-, and titanium-bearing constituents from diaspore-type bauxite ores was investigated by stepwise treatment consisting of pre-desilication via alkali-leaching of bauxite ore, extraction of alumina via Bayer process, and recovery of iron from red mud via magnetic separation. The pre-desilication results showed that the removal of silica reached 73.92% and...
The characteristics of microwave power absorption in materials for ferrous metallurgy, including iron oxides (Fe2O3, Fe3O4 and Fe0.925O) and bitumite, were explored by evaluating their dielectric loss (QE) and/or magnetic loss (QH) distributions in the 0.05-m-thick slabs of the corresponding materials exposed to 1.2-kW and 2.45-GHz microwave radiation at temperatures below 1100°C. It is revealed that...
The correlations between phase evolution, fusion behavior, and Ni-Fe granules growth of laterite ore–CaO mixtures during reductive roasting have been investigated. The minimum melting point of 1220°C of the CaO-MgO-Al2O3-SiO2 system with 17–36 wt.% CaO is demonstrated via phase diagram analysis, and this point is decreased in the presence of FeO. This reveals that the fusion behavior in close association...
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