Replacement behavior of Ti and Mg and selective separation of MgxTi3-xO5 (x=1, 0.9, 0.75, 0.6) from Ti-bearing electric furnace smelting slag via super-gravity

Ti-bearing electric furnace smelting slag produced from direct reduction and electric furnace smelting process of vanadium titanomagnetite ore, contains a high TiO2 content of 40–55 wt%. While a mass of Mg, Al, Ca and Si are closely mixed with Ti in the slag, which greatly limits the recovery of Ti resource from the slag. In this work, the replacement behavior of Ti and Mg in MgxTi3-xO5 was studied, and selective separation of various MgxTi3-xO5 phases from Ti-bearing electric furnace smelting slag was conducted via super-gravity. It was found that Mg could replace Ti in Ti3O5 and form the MgxTi3-xO5, and increasing of cooling rate greatly limited the doping of Mg into MgxTi3-xO5, the MgxTi3-xO5 was transformed from (MgTi2)O5 to (Mg0.9Ti2.1)O5, (Mg0.75Ti2.25)O5 and (Mg0.6Ti2.4)O5 respectively. On this basis, various MgxTi3-xO5 (x = 1, 0.9, 0.75, 0.6) phases were selectively separated from the smelting slag via super-gravity, where the mass fraction of TiO2 was increased from 78.69 to 90.32 wt% while that of MgO was decreased from 13.56 to 6.98 wt% with the increase of Ti/Mg ratio in MgxTi3-xO5. Moreover, the replacement mechanism of Mg and Ti was confirmed from characterization of crystal structure and lattice parameter of various separated high-purity MgxTi3-xO5 crystals.