Direct electrochemical extraction of Ti5Si3 from pressed cathode pellets comprising of powdered Ti/Sicontaining metal oxide compounds was investigated by using molten salt electro-deoxidation technology.Three groups of mixtures including TiO2 mixed with SiO2,Ti-bearing blast furnace slag（TBFS） mixed with TiO2, and TBFS mixed with high-titanium slag（HTS） were prepared at the same stoichiometric ratio（Ti:Si=5:3） corresponding to the target composition of Ti5Si3,and used as the starting materials in this experiment,respectively. The pressed porous cylindrical pellet of the Ti/Si-containing compounds served as a cathode,and two different anode systems,i.e.,the inert solid oxide oxygen-ion-conducting membrane（SOM） based anode system and graphite-based anode system were used contrastively.The electrochemical experiment was carried out at 900-1050℃and 3.0-4.0 V in molten CaCl2 electrolyte.The results show that the oxide components were electro-deoxidized effectively and Ti5Si3 could be directly extracted from these complex Ti/Si-containing metal oxide compounds.
In this paper,the thermodynamics of the reduction of ilmenite using multiple gases(H_2/CO) was calculated.It is found that the metallization rate of 20.1%-98.8%,H_2 consumption rate of 43.0%-99.1%,and carbon deposition amount of 5.7 × 10^(-7) — 0.49 mol can be obtained based on the conditions of hydrogen volume fraction of 10%-90%and temperature of 450-1200 ℃.Experimental study was also carried out using synthetic ilmenite as initial materials and reduced in a static bed reactor at 1100 ℃.The metallization rate reaches 97%when the multiple gas(70%H_2/10%CO/20%Ar) flow rate is 120 ml·min^(-1).A thermogravimetric analyzer was used to measure the variation of sample weight caused by the deposition of solid carbon.The amount of carbon deposited during experiments reaches its maximum while the original hydrogen volume content is 20%.The experimental results are well consistent with the thermodynamic analysis.
