Study On The Process Of Separation Between Slag And Metal During The Production Of Ti-Al-based Alloy From Sulphate Titanium Slag By Aluminothermic Reduction

There are rich titanium resources in the area of Panzhihua and Xichang,but most of them are not efficiently utilized.The sulphate titanium slag produced by the factories in Panzhihua has a high content of calcium and magnesium,which makes it unsuitable for producing sponge titanium and chloridization titanium white directly.Most of them are used to produce titanium dioxide by sulfuric acid method,which causes serious environmental pollution.Ti-Al-based alloy has lots of excellent properties,such as low density,high specific strength and thermostability etc.,and it has received considerable attentions as high temperature structural materials.Therefore,how to achieve better comprehensive utilization of titanium resources in Panzhihua and Xichang and develop an environment friendly,high-efficiency,energy saving and simple method for preparing Ti-Al-based alloy have attracted much attention from researchers.In this paper,the sulphate titanium slag from Panzhihua is used as raw material to prepare Ti-Al-based alloy by using aluminothermic reduction,and the problem that the slag cannot be separated easily and conveniently is investigated.This paper first made a thermodynamic analysis of aluminothermic reduction of titanium slag system.To solve the slag-metal separation problems during the reduction process,the Stokes Law is used as the basis,and the properties of the molten slag probably produced during the aluminothermic reduction preparation of titanium aluminum based alloys were calculated and analyzed using thermodynamic software FactSage.Orthogonal test was used to choose better parameters for the separation of slag and metal and identity the type of slag which was beneficial to the separation.At the same time,based on the optimized scheme obtained from the orthogonal experiment,the effects of the aluminum addition,CaO addition,temperature and holding time on the slag-metal separation were investigated.Finally,the intensified separation of the slag and metal assisted by high gravity was put forward,and the related experimental devices were designed.The following conclusions were drawn:(1)With the aid of thermodynamics software FactSage,the simulation and calculation done showed that when CaO/Al2O3 ratio was 0.8,1 and 1.2,and added TiO2,MgO or both into the CaO-Al2O3-based slag system.CaO/Al2O3 ratio of 1.2 for slag was the most conducive to the slag-metal separation theoretically,however,its viscosity was very sensitive to the tempreture.(2)The experiment of the slag-metal separation revealed that,by adjusting the ratio between the different raw materials and controlling the temperature and holding time,the degree of the slag-metal separation could reach the highest level of 92.66%,and when the composition of the reducing slag was close to C-type slag(CaO/Al2O3 was 0.8 corresponding slag system),the slag-metal separation degree and the alloy aggregation were the best.(3)The theoretical analysis of the high gravity separation of slag and metal showed that the high gravity by changing the acceleration of gravity g to intensify the effect of slag-metal separation,and the experimental device which was used to produce high gravity was designed.