Study On Vacuum Aluminothermic Reduction To Preparing Titanium

Titanium is a kind of structural and functional material,which has many desirable properties,such as being light,strong,corrosion-resistant,and widely temperature adapt ability.In this paper,study on thermodynamic analyzes of the experiments that with aluminum powder as the reducing agent,Na2TiF6 and NaF as raw materials to preparing titanium,study on aluminum vacuum aluminothermic reduction experiments and molten salt electrolysis experiments,at the same time,research molten salt electrolysis experiments with electrochemical analysis,the research results were as follows:Through the thermodynamic analysis of vacuum thermal reduction,Na2TiF6 is more easily to be reduced to titanium with aluminum powder as the reducing agent,measure actual reaction temperature of aluminothermic reduction reaction at 570?.In the process of vacuum aluminothermic reduction,with the increase of temperature,extend holding time,increasing the amount of reducing agent,and the degree of reduction of Na2TiF6 improved,the aluminum content of products decreased and the titanium content of by-products cryolite containing titanium increased after reduction.The experiments show that the reduction temperature of 1000 ?,insulation time of 1.5 h,excessive coefficient of reducing agent of 4%,reaction temperature,time of 45 min is the ideal reduction experiment condition,It can be reduced a pure titanium.The main phase in the reducing by-product is Na3AlF6,it also contains a little amount of Na3TiF6,Na5Al3F14 and Ti phase.In the process of molten salt electrolysis experiments,that with by-products cryolite containing titanium as addition agent into the electrolyte for molten salt electrolysis to prepared aluminum titanium alloys,with the extension of electrolysis time,titanium content of electrolytic aluminum titanium alloy will gradually rise,titanium recovery rate is also improved,and,the amount of addition agent in the electrolyte and cell voltage have little effects on the electrolytic process.The experiments show that on this condition about the electrolysis time of 3.5 h,10%for the amount of additive,cell voltage of 3.0 V,it can get aluminum titanium alloys.Thermal reduction of by-products cryolite containing titanium as additives into the electrolyte for molten salt electrolysis to prepared aluminum titanium alloys.the mainly phase of titanium in aluminum titanium alloys is TiAl3,and the distribution of TiAl3 which appears dendrite structure is in the alloy substrate.With the increase of titanium content,dendrite structure of the alloy structure Become thick and long from short and fine,also become intensive.Electrochemical analysis of molten salt electrolysis process shows that in the process of electrolysis,separating out the reduction of aluminum,sodium,titanium.Titanium exists two kinds of different valence,direct reduction for titanium from +2 and +3 valence,the electrochemical potential is 0.1 V and 0.4 V respectively.In this paper,the research results show that Na2TiF6 and NaF as raw materials to the vacuum aluminothermic reduction of preparing titanium is completely feasible,aluminium content of product by the reduction reaction at about 1%,the by-product cryolite containing titanium can make the titanium content reduced to less than 0.008%after molten salt electrolysis,at the same time it can get aluminum titanium alloy.The method can be Applied to production of titanium and aluminum titanium alloy,the production process does not produce waste slag,which can achieve the efficient utilization of titanium resources,the experiment can eventually get three products,such as metal titanium,aluminum alloy and cryolite,it has a good application prospect.