An innovative method of production of metallic Ti powder via titanium oxycarbonitride and titanium sulfide synthesized from ilmenite

提出了以钛铁矿（FeTiO3）为原料，通过tix （1<x<2）和TiN制备钛金属粉末的新工艺思路。以FeTiO3为原料，采用碳热还原和氮化（CTRN）法制备了TiN或TiOxCyNz。从TiN中制备干净的TiS2是生产高纯度Ti粉的关键。CS2或S2气体均可用于由TiOxCyNz或FeTiO3合成硫化钛。然而，CS2气流会导致样品的污染。专门制造的双区炉使硫逐渐蒸发，并能控制S2气的分压。使用S2气体可以显著抑制碳污染。在1473 K下，TiN分别在3.6和10.8 ks下转变为Ti2.45S4和TiS2的单相。当样品在1473 K下硫化10.8 ks时，硫化物的氮含量降至<0.005 mass% N。然后，在加入少量CaS的熔融CaCl2中，采用电化学OS法将硫化物还原为Ti金属粉末。硫化物样品的碳杂质含量降至0.01质量% C，钛粉样品的碳杂质含量降至<0.1质量% C。研究了TiC的硫化作用，在1473 K温度下，经过18 ks，制备出了碳含量<0.025质量% C的纯TiS2样品，适用于Ti粉的生产。通过在熔融CaCl2-0.5 mol%的ca中电化学还原TiN或TiC，成功地制备了由O < 0.15 wt%的片状Ti片组成的球形Ti粉。利用这一建议，可以通过它们的硫化物制备Ta和Nb粉末。

A new processing concept for production of Ti metal powder via TiSx (1<x<2) and TiN from ilmenite (FeTiO3) has been proposed. TiN or TiOxCyNz was synthesized by carbothermal reduction and nitridation (CTRN) of FeTiO3.The preparation of clean TiS2 from TiN plays a key role in production of high-purity Ti powders. Either CS2 or S2 gas could be used for synthesis of titanium sulfides from TiOxCyNz or FeTiO3. However, CS2 gas stream leads to contamination of the samples. A dual-zone furnace specially manufactured gradually evaporated the sulfur and could control the partial pressure of S2 gas. The carbon contamination was remarkably suppressed using S2 gas.TiN was thus transformed to the single phase of Ti2.45S4 and TiS2 at 1473 K for 3.6 and 10.8 ks, respectively. Nitrogen content of the sulfide was reduced to <0.005 mass% N when the sample was sulfurized at 1473 K for 10.8 ks. Then, the sulfide was reduced to Ti metal powder by the electrochemical OS process in molten CaCl2 with a small addition of CaS. The carbon impurity decreased to 0.01 mass% C for the sulfide and <0.1 mass% C for the Ti powder samples.Sulfidation of TiC was also studied and pure TiS2 samples with carbon content of <0.025 mass% C were prepared at 1473 K for 18 ks, which is applicable for producing Ti powder. We successfully produced Ti powders with spherical morphology consisted of the foil-like Ti sheets with < 0.15 wt% O from TiN or TiC by the electrochemical reduction in molten CaCl2-0.5 mol% CaS. Using this proposal, Ta and Nb powders could be prepared via their sulfides.