Distribution of niobium and vanadium in titanium tetrachloride production middlings

Abstract

This paper describes the results of a study that looked at the distribution of niobium and vanadium at different stages of titanium slag and titanium tetrachloride production. The former is produced by smelting while the production of the latter is based on chlorination of titanium feedstock in molten alkali metal salts. Titanium feedstock was subjected to reduction smelting at 1.400–1.600 oC in the presence of carbonaceous reducing material. In this case, an AM grade of anthracite was used as such material. The resulting titanium slag was ground and dried and then it was subjected to chlorination at 700–820 oC in molten alkali metal salts in the presence of ground anthracite as the carbonaceous reducing material. The findings indicate that 99.9% of niobium and 84.9% of vanadium convert to the titanium slag produced through the smelting of ilmenite concentrate. The following distribution of niobium in the middlings can be observed at the following stage when the slag is chlorinated in molten salts to obtain titanium tetrachloride: 37% goes to the chlorinator tailings, 3% gets trapped in the dust chamber as part of chloride fumes, 1.8% gets settled in the melt of the settling chamber with a salt bath, and 58.2% gets accumulated as a solid deposit of titanium tetrachloride slurry at the first condensation stage. Out of the total amount of vanadium that is fed into the chlorinator with titanium feedstock, 13.9% goes to the tailings while 78.4% gets recovered as commercial titanium tetrachloride. During the following purification stage, 0.33% of vanadium remains in the purified titanium tetrachloride while the rest of it goes into the waste bottoms.