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In this study, reaction steps of a process for synthesis of titanium oxycarbide from titanium slag were demonstrated. This process involves the reduction of titanium slag by a methane-hydrogen-argon mixture at 1473 K (1200 °C) and the leaching of the reduced products by hydrofluoric acid near room temperature to remove the main impurity (Fe3Si). Some iron was formed by disproportionation of the main M3O5 phase before gaseous reduction started. Upon reduction, more iron formed first, followed by reduction of titanium dioxide to suboxides and eventually oxycarbide.

Unweathered ilmenite, weathered ilmenite, and a rutile-rich (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.

Titanium metal production by the Kroll process requires a high-grade ore material as a feedstock for chlorination, such as natural or synthetic rutile. Electrochemical methods for making titanium have generally required even higher purity. This paper describes different methods for iron removal from a pseudorutile mineral sand for the eventual goal of producing commercially pure titanium powder by the MER electrochemical process. One method involves the dissolution of the Fe $$_2$$ O $$_3$$ content of the ore in an alkali chloride molten salt, followed by plating to remove the dissolved species as metallic iron. The other method described involves the reduction of the ore to titanium oxycarbide, which also reduces iron and some other metal oxides present to metallic form. This reduced material is used as an anode in an electrochemical cell, and the metallic impurities are selectively removed by careful control of the anode potential. The products of both processes are compared with respect to their impurity contents, and their potential applications to different titanium production methods are also examined.

A process to remove impurities from titanium oxycarbide–the feedstock used to make titanium via the MER electrochemical process–from impure oxycarbide produced from low-grade feedstocks such as ilmenite is described. Titanium oxycarbide produced by carbothermal reduction from a natural ilmenite concentrate will contain many metallic impurities, such as iron, manganese, and silicon. If these impurities are not removed, then these metallic impurities will contaminate the titanium product. The MER process can be modified into a two-step process to first remove the contaminating metallic impurities before titanium production begins. A simplified system has been used to test this iron removal method, and the titanium oxycarbide produced by this first electrochemical step has been characterized to determine its impurity content.

The metal–organic framework UiO-66-NH2 was synthesized in a scaled batch of approximately 100 g. The material was then pressed into small pellets at pressures ranging from 5000 to 100000 psi to determine the effects on porosity and crystal structure. Nitrogen isotherm data and powder X-ray diffraction data indicate that the structure remains intact up to 25000 psi, with only a slight decrease in surface area. The structure exhibits significant degradation at pressures above 25000 psi. Subsequently, the powder was pressed at 5000 psi and then crushed and sieved into 20 × 40 mesh granules for evaluation against ammonia and cyanogen chloride in a breakthrough system simulating individual protection filters and respirator cartridges. The MOF showed capacity similar to that of a broad-spectrum carbon for both ammonia and cyanogen chloride; however, the breakthrough times, especially for cyanogen chloride, were dramatically reduced, likely as a result of mass-transfer limitations from the completely microporous...

The production of synthetic rutile using a novel electrochemical process using a molten salt electrolyte is described. The product produced by this process is of similar quality and composition to existing synthetic rutile materials, which are used as a feedstock to many titanium and pigment production processes. The mechanism that underlies this process is the solubility of iron(III) oxide in chloride salts, which can then be reduced electrochemically, producing metallic iron, and leaving behind synthetic rutile. The effect of electrolyte composition is also investigated.

The production of synthetic rutile—a common starting material for most titanium production processes—from iron-rich titanium minerals such as pseudorutile and ilmenite is described. The process for “upgrading” the mineral to synthetic rutile is by carbothermal reduction of the mineral while immersed in a molten salt at high temperature, followed by magnetic separation of the reduced iron. A variety of factors are also investigated, such as particle size of the mineral, the type of mineral, and the molten salt used. The solubility of iron(III) oxide in different molten salts is also experimentally determined.

The production of titanium oxycarbide — a consumable anode material used in molten-salt processes for electrowinning titanium — from heavy mineral concentrate, such as a high-titania leucoxene and natural rutile is described. The oxycarbide is prepared by carbothermic reduction of the oxide at elevated temperature. Particle size distribution (of the titanium oxide raw material) and temperature have large effects on the kinetics of the reaction, which seem to follow a “shrinking-core” model. It is anticipated that low porosity (in the anode pellets) would be advantageous during electrolysis. Particle size distribution, extent of reaction during carbothermic reduction, and sintering temperature are expected to affect pellet porosity after sintering, and are being tested experimentally.

The free energy of mixing in the Ti(O,C) shows negative deviation from ideality. A recent paper, Journal of Materials Chemistry A, 2014, 2, 2641, erroneously shows a large positive deviation from ideality.

Titanium production is a long and complicated process. What we often consider to be the standard method of primary titanium production (the Kroll process), involves many complex steps both before and after to make a useful product from titanium ore. Thus new methods of titanium production, especially electrochemical processes, which can utilize less-processed feedstocks have the potential to be both cheaper and less energy intensive than current titanium production processes. This project is investigating the use of lower-grade titanium ores with the electrochemical MER process for making titanium via a molten salt process. The experimental work carried out has investigated making the MER process feedstock (titanium oxycarbide) with natural titanium ores|such as rutile and ilmenite|and new ways of using the MER electrochemical reactor to \upgrade" titanium ores or the titanium oxycarbide feedstock. It is feasible to use the existing MER electrochemical reactor to both purify the titanium oxycarbide feedstock and produce titanium metal.