| Vanadium was used in steel industry,aviation industry,energy,the nuclear industry and chemical industry oil and other fields.Industrial production method of titanium is discontinuous,complex,high cost,which has seriously restricted vanadium extensive application.Electro-deoxidation method(FFC) is a kind of continuous and low cost new technology for the preparation of refractory metal,for the preparation of metal vanadium provides a new way of thinking.However,nowadays research focus on CaCl2and other alkali metal chloride molten salt system.Because of chloride system easy to absorb moisture,high background current,low efficiency,and the product easy to be carbon pollution and easy to precipitate chlorine gas,so this research adopts the industrial cryolite molten salt system.Multi-ammonium vanadate as raw material,preparation of V2O3by preforming,reduction and sintering.the V2O3as cathode piece electrolytic preparation of metal vanadium to shorten the process and improve the efficiency of electrolysis.Investigating the effects of gas flow,reduction temperature and time on the vanadium content,and determine the optimum sintering conditions.The results show that the optimal process:245MPa molding pressure,2%bingder amount,21.21%moisture content,lL/min gas flow,750℃temperature,30min reduction time,1200℃sintering temperature,2h sintering time,the purity of V2O3over90%.Graphite crucible as anode,V2O3pellet as cathode for electro-deoxidation prepar vanadium in industrial cryolite molten salt.Determine the optimum process parameters:1000℃temperature electrolysis,3h electrolysis time,3.5V cell voltage,0.3%-0.5%alumina concentration,the current efficiency is43.80%,recovery rate of vanadium is94.82%.Reduction mechanism study shows that the oxygen in V2O3is removed by oxygen ionization,the electrolytic reduction process:V2O3â†'VOâ†'VO2-and [AlF4]-or [AlF6]3-to produce Al2O2F42-is the main reason for the electrolytic rate is higher than the chloride molten salt system. |
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