Synthesis of Titanium Oxycarbide from Concentrates of Natural Ilmenite (Weathered and Unweathered) and Natural Rutile, U
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Unweathered ilmenite, weathered ilmenite, and a rutilerich (zircon-containing) concentrate were reduced with 39 pct H2-6 pct CH4 (balance Ar) reduction gas at 1473 K (1200 °C). Despite differences in initial iron content, phase composition, and thermal stability of the phases, the main steps of the reaction sequence for the three materials were the same. The metallic iron product could be removed by leaching. In all cases, the product after leaching was a carbon-rich titanium oxycarbide. DOI: 10.1007/s11663-017-1048-z Ó The Minerals, Metals & Materials Society and ASM International 2017
Iron-bearing titaniferous minerals such as ilmenite or pseudorutile can be cost-effective materials for production of titanium oxycarbide; such titanium oxycarbide would be useful material for titanium metal production if metallic elements other than titanium can be removed before or after production of the oxycarbide.[1] Ilmenite is the lowest-cost practical titanium feedstock, but varies greatly in properties such as chemical composition, particle size, and porosity. To test these effects, this work considered two ilmenites, one unweathered and one highly weathered, together with a natural rutile, and
JIE DANG is with the State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China, and with the Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, and also with the College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China. FARZIN FATOLLAHI-FARD and PETRUS CHRISTIAAN PISTORIUS are with the Department of Materials Science and Engineering, Carnegie Mellon University. Contact e-mail: pistorius@ cmu.edu KUO-CHIH CHOU is with the State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing. Manuscript submitted January 15, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS B
also different particle sizes (obtained by grinding the concentrates). Another effect that was studied is the deportment of silicon—under the highly reducing conditions needed to produce titanium oxycarbide, it should be possible to reduce silica, dissolving silicon into iron, or forming a silicide such as Fe3Si. It appears that this reaction was not considered in previous work. The possibility to upgrade iron-containing oxycarbide by leaching the iron was tested, and results reported here. In earlier work, Zhang and Ostrovski[2] reported that Australian ilmenite can be reduced in CH4-H2-Ar mixtures with the formation of metallic iron and titanium oxycarbide at temperatures of 1223 K (950 °C) and above, and that the optimum temperature is 1473 K (1200 °C). Natural ilmenite can vary considerably in degree of weathering, resulting in different iron contents and phase compositions; Gupta et al.[3] found that the degree of weathering of ilmenite has a great effect on the reduction by carbon. In contrast, Gao et al.[4] found that carbothermic reduction of quite different raw materials (ilmenite cont
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