Becher process

Abstract: Typically, pure TiO2 in pellet form has been utilised as the feedstock for the production of titanium metal via the solid state extraction FFC process. For the first time, this paper reports the use of loose synthetic rutile powder as the feedstock, along with its full characterisation at each stage of the reduction. The kinetics and mechanism of the reduction of synthetic rutile to a low oxygen titanium alloy have been studied in detail using a combination of X-ray diffraction, scanning electron microscopy, oxygen analysis, and X-ray fluorescence techniques. Partial reductions of synthetic rutile enabled a reaction pathway to be determined, with full reduction to a low oxygen titanium alloy occurring at 16 h. Major remnant elements from the Becher process within the feedstock were followed throughout the process, with a particular emphasis placed on the reduction behaviour of iron within the alloy. Although impurities such as Fe, Al, and Mn are found in the feedstock and alloy, no major deviations from previously reported reaction mechanisms and phase transformations utilising a pure porous (25–30 % porosity) TiO2 precursor were found. Following reduction, the titanium alloy powder produced from synthetic rutile (approx. 3500 ppm oxygen) has been consolidated via an emerging rapid sintering technique, and its microstructure analysed. This work will act as the baseline for future alloy development projects aimed at producing low-cost titanium alloys directly from synthetic rutile. Producing titanium alloys directly from synthetic rutile may negate the use of master alloy additions to Ti in the future.

Abstract: An innovative and sustainable carbothermal reduction and nitridation (CTRN) process of ilmenite (FeTiO3) using a mixture of polyethylene terephthalate (PET) and coal as the primary reductant under an H2–N2 atmosphere was proposed. The use of PET as an alternative source of carbon not only enhances the porosity of the pellets but also results in the separation of Fe from titanium oxycarbonitride (TiO x C y N z ) particles because of the differences in surface tension. The experiments were carried out at 1250°C for 3 h using four different PET contents ranging from 25wt% to 100wt% in the reductant. X-ray diffraction (XRD), scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDX), and LECO elemental analysis were used to study the phases and microstructures of the reduced samples. In the case of 75wt% PET, iron distinctly separated from the synthesized TiO x C y N z phase. With increasing PET content in the sample, the reduction and nitridation rates substantially increased. The synthesis of an oxycarbonitride with stoichiometry of TiO0.02C0.13N0.85 with minimal intermediate titanium sub-oxides was achieved. The results also showed that the iron particles formed from CTRN of FeTiO3 exhibited a spherical morphology, which is conducive for Fe removal via the Becher process.