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Fe–TiC powder composite was successfully synthesized from mixtures of ilmenite concentrate (FeTiO3) and carbon black through mechanical activation and subsequent reduction at a temperature that was considerably lower than that used in conventional carbothermic reduction synthesis. Mixed ilmenite powder and carbon black were milled in a planetary ba...
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... starting materials were ilmenite concentrate with mean particle size of 90 μm. Its chemical composition is listed in Table 1 and carbon black powder (190 μm) with a high purity of more than 99% was used as the reducing agent. Ilmenite and carbon were mixed at the stoichio- metric ratio of 4:1 to provide sufficient carbon for full reduction of ilmenite to TiC and Fe according to the following reaction: ...
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... However, it was noted that a further increase in temperature from 1000 °C upward could lead to the continuous disappearance of TiO 2 until stable phases of sub-oxides (magneli) of titanium, e.g. Ti 4 O 7 and Ti 3 O 5 , are formed [34,35]. ...
A systematic study on the mechano-thermic reduction of low-grade ilmenite concentrate for the production of high-grade TiO2 powder used in the production of non-oxide ceramics for cutting tool applications has been successfully carried out. Samples were prepared via planetary ball milling and carbothermic reduction processes, and the as-reduced product was subsequently leached in order to improve the synthesized TiO2 by removing the metallic iron in it and other minor soluble impurities dissolved in the iron. The mechano-thermic reduction was achieved by milling a representative mixture of ilmenite and carbon in a molar ratio of 1:1, followed by carbothermic reduction at 1000 °C in a laboratory high-temperature furnace for 60 min. The as-reduced product was subsequently leached at 80 °C for 6 h in a hydrochloric acid solution. It was found that there was a complete reduction of ilmenite to metallic iron and TiO2 at 1000 °C. The results of the FESEM showed there were only two distinct regions of metallic iron (bright region) and titanium dioxide (grey region) with minor traces of unreacted carbon (dark spots), although there was clear regional demarcation between these regions. However, the iron dissolution during the acid treatment was almost 100% as there were no peaks of iron in the as-leached powder. The results of these analyses confirmed the synthesis of high-grade TiO2, which finds application in cutting tool applications and other areas such as in reflective pigment production.
... Однако при этом вместо частиц карбида TiC были синтезированы частицы оксикарбида Ti(O,C), что было связано с меньшей температурой восстановления. Улучшение эффективности рассматриваемого метода было достигнуто при использовании высокоэнергетической механической активации смеси реагентов [15,16]. Механическая активация в течение 30 ч смеси ильменита и сажи позволила снизить температуру синтеза с 1300 до 1200 °С и за 3 ч успешно синтезировать порошковый композит TiC-Fe [16]. ...
... Улучшение эффективности рассматриваемого метода было достигнуто при использовании высокоэнергетической механической активации смеси реагентов [15,16]. Механическая активация в течение 30 ч смеси ильменита и сажи позволила снизить температуру синтеза с 1300 до 1200 °С и за 3 ч успешно синтезировать порошковый композит TiC-Fe [16]. Не-смотря на использование дешевого сырья, метод карботермического восстановления приводит к достаточно длительной и энергоемкой технологии получения кермета TiC-Fe. ...
... Researchers have also tried to prepare Fe-TiC composite through MSA process and thermal plasma process from the cheaper ilmenite concentrate and carbon black. 22,23 However, the process requires a long time (∼50 h) and the impurity phase still presents in the final products. ...
Fe-TiC composite has been directly synthesized from natural ilmenite/carbon mixture precursors at 900–1000◦C and 3.1–3.8 V in molten CaCl2. The pressed natural ilmenite/carbon mixture pellet was used as the cathode, and an inert solid oxide oxygen-ion-conducting membrane (SOM) tube filled with carbon-saturated liquid tin as well as a graphite rod were employed as the anode, respectively. The reaction mechanism of the electroreduction process from ilmenite/carbon mixture to Fe-TiC has been discussed based on the Rietveld refinement analysis, and the characteristic of the produced Fe-TiC composite has also been systematically analyzed. The result shows that the SOM-based anode electrochemical process possesses higher current efficiency compared with the graphite-based anode electrochemical process. The electrochemical process shows a considerable reduction speed due to the reinforcement of the in-situ reduction-generated Fe. The produced Fe-TiC composite shows homogenous structure. In addition, nanoscale TiC particles can be further produced through a facile leaching process from the obtained Fe-TiC composite. The TiC powder synthesized through the electrochemical process is of great potential to be used for the refinement for aluminum and/or aluminum alloys.
... [1][2][3][4][5][6] Titanium carbide powders are oen used for manufacturing cutting tools, aerospace materials, grinding wheels, abrasive-resistant materials, polishing paste, and magnetic recording heads, as well as crucibles for smelting metals. [7][8][9][10] In cermets, titanium carbide can substitute for another transition metal carbide, tungsten carbide (WC), because of their similar properties such as high hardness and high resistance to corrosion. The most important benet can be attributed to the fact that titanium carbide needs a cheaper binder nickel (Ni) in comparison with cobalt (Co), which is required in WC based cemented carbide. ...
In the present work, nano-sized titanium carbide (TiC) particles were successfully synthesized through a process of producing carbon coated titanium precursors, heating these precursors under vacuum conditions at 1450 °C for 2 h, and treating the products in hydrogen/argon (1:1) mixed gas or hydrogen gas. The effects of carbon content, pressure and temperature of removing excess carbon on the TiC products were examined by using XRD, SEM, TEM and DTA-TG analysis. Experimental results demonstrated that TiC powders with a single phase were obtained when the molar ratio of Ti to C ranged from 1:2 to 1:4. With changing the molar ratio of Ti/C in the precursors, the particle size of the synthetized TiC powders varied from 30 to 200 nm. After treatment in the hydrogen/argon mixed gas at 830 °C for 3 h, the TiC product accounted for a high TiC purity of 99.36% and possessed a small grain size of about 20 nm. The vacuum calcination method coupled with the hydrogen/argon mixed gas process applied in this work would be an efficient way to obtain nano-sized and purified TiC particles, which hold great promising for industrial purposes.
... On comparing the above results with ilmenite concentrate results [20], it can be concluded that different behaviors of the three mixtures after reduction at 1200 and 1300°C for 3 h are obtained. In the case of the ilmenite concentrate mixture, only 30 h mechanical activation was required to produce Fe-TiC at 1200°C. ...
... In the case of the ilmenite concentrate mixture, only 30 h mechanical activation was required to produce Fe-TiC at 1200°C. Increasing the reduction temperature to 1300°C was not recommended due to formation of closed shells of metallic iron around ilmenite grains which seriously prevents the gaseous reduction to proceed [20][21]. Conversely, in the case of the black sand ilmenite mixture, 50 h mechanical activation was needed to produce Fe-TiC composite at 1200°C. ...
Preparation of Fe-TiC composite from mixtures of carbon black and two different titanium bearing minerals (black sand ilmenite and natural rutile) was studied. Milled (mechanically activated) and unmilled carbon containing mixtures were prepared and then heated at temperatures 1200°C and 1300°C for 3 h under an inert atmosphere. The reaction progress, as well as reaction products, was evaluated using thermogravimetric analysis (TGA-DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). The feasibility of producing Fe-TiC composites from titanium bearing materials mixed with carbon black was proved. Fe-TiC could be produced by carbothermic reduction of mechanically activated black sand ilmenite containing mixtures milled for 50 h and heated up to 1200°C. On the other hand, 60 h milling followed by heating up to 1300°C was needed in case of natural rutile containing mixture. The morphology of the Fe-TiC produced from black sand ilmenite showed a homogeneous distribution of Fe and TiC enriched areas, while the Fe-TiC produced from natural rutile showed intense distribution of TiC phase with traces of iron and lower titanium oxide.
A systematic study on the mechano-thermic reduction of low-grade ilmenite concentrate for the production of high-grade TiO 2 powder used in the production of non-oxide ceramics for cutting tool applications has been successfully carried out. Samples were prepared via planetary ball milling and carbothermic reduction processes, and the as-reduced product was subsequently leached in order to improve the synthesized TiO 2 by removing the metallic iron in it and other minor soluble impurities dissolved in the iron. The mechano-thermic reduction was achieved by milling a representative mixture of ilmenite and carbon in a molar ratio of 1:1, followed by carbothermic reduction at 1000°C in a laboratory high-temperature furnace for 60 min. The as-reduced product was subsequently leached at 80°C for 6 h in a hydrochloric acid solution. It was found that there was a complete reduction of ilmenite to metallic iron and TiO 2 at 1000°C. The results of the FESEM showed there were only two distinct regions of metallic iron (bright region) and titanium dioxide (grey region) with minor traces of unreacted carbon (dark spots), although there was clear regional demarcation between these regions. However, the iron dissolution during the acid treatment was almost 100% as there were no peaks of iron in the as-leached powder. The results of these analyses confirmed the synthesis of high-grade TiO 2 , which finds application in cutting tool applications and other areas such as in reflective pigment production, etc.
The application of the SHS reactions yielding TiC coupled with the reduction of Fe from iron oxide to preparation of TiC–Fe powders from plain and granulated green mixtures was overviewed with special emphasis on (Fe2O3 + 2Al)–(Ti + C) (I) and (Fe2O3 + 3C)–(Ti + C) (II) compound mixtures. In case I of aluminothermic reduction, green (Ti + C) + x(Fe2O3 + 2Al) charges were prepared as a mixture of granules prepared separately from thermite (Fe2O3 + 2Al) and carbide (Ti + C) blends. In case II of carbothermic reduction, green (Ti + C) + x(Fe2O3 + 3C) mixtures were used without preliminary granulation. In both cases, combustion in an open reactor proceeded steadily without material splashing and yielded highly porous Fe(Al)–Fe3Al–Al2O3–TiC or TiC–Fe cermets that can be easily grinded to get abrasive powders. The above reactions are energy saving, technically simple, cost effective, and rather promising for R & D of industrial-scale processes to fabricate powdered TiC–Fe cermets to be used as abrasive materials, wear-resistant coatings, and catalysts.
Al2O3-TiC/Fe metal-base ceramic composite materials were prepared by means of powder metallurgy method with TiC, C, Mn, Ni, Mo, α-Al2O3 powders and reduction of Fe powder as the main raw materials. It was sintered in a tube vacuum sintering furnace (φ 150 mm)with high vacuum of 2.5 Pa, 1530°C, holding time of 90 min. The influences of different rare earth on water absorption, bulk density, microstructure and wear-resistant property were investigated. The results show that the water absorption and bulk density (0.0310% and 6.7770 g/cm3 respectively) of Al2O3-TiC/Fe cermets wear the optimum by doping 0.3wt% Y2O3, and the wear resistance is improved.
In this research, synthesis of Fe-TiC nanocomposites from activated ilmenite concentrate and carbon black was investigated. Ilmenite and carbon black as raw materials were milled in a planetary ball mill and sampled after different milling times. The activated powder was heat treated at different temperatures in an atmosphere control tube furnace and analyzed by X-ray diffraction technique. The X-ray diffraction results showed that increasing the milling time would lower the synthesis temperature of final products. Furthermore, the lattice parameter showed deviation from standard size, and mean grain size was decreased. In contrast, the strain of the system was increased based on the calculations.
