The Basic Research Of Preparating Rich Titanium Materials By Carbothermal Reduction-nitridation With Ilmenites

There are many titanium resources in the area of Panzhihua and Xichang.The ilmenite produced by the factories in Panzhihua has a high content of calcium and magnesium,which makes it inadaptable for producing chloridization titanium white directly.Carbothermal reduction-nitridation of ilmenite can selectively be chlorinated at low temperatures.In the low temperature,the impurities such as calcium and magnesium which are not be chlorinated can't affect the chloride process,so it can realize the selective chlorination and reduce the chlorine consumption in chloride process.In this paper,the rich titanium materials which include TiN?TiC and Ti-C-N were prepared by carbothermal reduction-nitridation method with Panzhihua ilmenite as raw material.Firstly,this paper analysed the thermodynamics,carbon content and equilibrium components of the carbon reduction reaction of ilmenite,then researched the pelletizing process parameters by pelletizing under the condition of inner carbon experimental.And by using X-ray diffraction,optical microscopy and scanning electron microscopy observed the effects of temperature,holding time,nitrogen flow rate and carbon content in the process of carbothermal reduction-nitridation of ilmenite.Finally,numerical modeling described the temperature field inside the reactor under different nitrogen flow rate and the effect of nitrogen flow on the temperature of the whole nitriding reaction system.The thermodynamic calculation and balance component shows that: the route of preparing TiN in FeTiO3 by carbothermal reduction nitridation under 1250? is FeTiO3?TiO2?Ti3O5?TiN;The route of preparing TiC in FeTiO3 by carbothermal reduction nitridation under 1200? is FeTiO3?TiO2?TiC,but FeTiO3?TiO2?Ti3O5?TiN will happen at the same time temperature.The experimental parameters optimization of pellet preparation under the condition of inner carbon results show that the largest influencing factor of the pellets in the ilmenite is the PVA concentration.The maximum shatter number of the pellets in the process conditions is 0.4 percent of PVA,4 percent of water,5MPa pressure.The experiment of carbothermal reduction-nitridation of ilmenite revealed that TiC is mainly produced in TiO2 at the beginning of the reaction and the content of C in TiN(C)system is the main one.However,with the prolonging of the holding time,Ti is reduced more completely and the content of N increase in the carbonitriding system.When the nitrogen flow rate is from 0.085 m/s to 0.17 m/s,the nitriding effect of ilmenite is obviously improved and the nitrogen flow rate is increased.However,The reduction of Fe2TiO5 in the system is inhibited when the nitrogen flow rate is 0.21 m/s.With increasing the carbon content,the reduction of Fe2TiO5 can be obviously increased and the content of Ti and C also increased,at the same time,the content of N in the product decrease obviously.The numerical simulation of titanium rich material prepared by carbothermal reduction nitridation of ilmenite show that:the nitrogen flow rate has a great influence on the distribution of nitrogen and the free flow region in the whole process,which leads to the lack of nitrogen concentration in the local area and the nitriding effect is not ideal.In the high-speed region of nitrogen,with the inlet position as the center,there is a clear low-temperature zone in the certain diameter of the circular area(diameter size determined by the flow rate).The temperature increases from inside to outside and the internal temperature field of the crucible is reduced by nitrogen entry as the reaction time progresses.