Research On Preparing Vanadium Nitride From NH₄VO₃ By One-step Method

At present,in response to China's steel industry,crude steel production increased year by year,functional steel production and other issues,China's"13th Five-Year Plan"on the steel industry put forward new requirements to resolve the excess capacity of the steel industry to promote the transformation and upgrading of the steel industry,Enhance the quality of steel products has become China's current development of the steel industry benchmark.Vanadium in the domestic steel industry in the demand for its total amount of 75%to 90%,and has been used in the form of vanadium iron,mainly used in machinery,chemicals,aerospace,defense and other industries.Since the 21st century,nitrogen as an additive gradually applied to the steel industry,steel nitrogen can be better to refine and strengthen the grain,has gradually replaced the vanadium iron is widely used in the steel industry,vanadium nitride as A new type of alloy additive,in enhancing the performance of steel,energy conservation and other aspects compared to vanadium iron has obvious advantages.In this paper,we study the preparation of vanadium nitride by one step reduction nitridation.Through the thermodynamic analysis of the reduction process with ammonium metavanadate as oxides,nitrides and carbides in one-step prepared vanadium nitride vanadium in vanadium nitride,The order of reaction of raw materials in the preparation process of vanadium nitride was NH₄VO₃?V₂O₅?VO₂?V₂O₃?VC?VN.According to the thermodynamic principle,the effects of reaction conditions,such as pressure,temperature and specific surface area of the reaction system,on the reduction and nitridation process were investigated.The kinetic behavior of vanadium nitride synthesis by one-step synthesis of ammonium metavanadate was studied by thermogravimetric analysis and differential thermal analysis.When the temperature was below 780K,the rate constant of the curve was 0,which shows that the reaction time And the reaction rate is constant.At this stage,the nitriding reaction does not occur.When the temperature rises to 780K⁹00K,the rate constant curve shows a symmetrical change,which increases first and then decreases.The reaction rate constant Fluctuation represents a one-step synthesis of vanadium nitride during the carbonation process,the raw material of ammonium metavanadate in this temperature range of full reaction;with the reaction time,after 200min,when the temperature gradually increased to1000¹200K Figure 4.3 shows that the reaction rate constant shows a tendency to increase first and then decrease and reach a maximum rate constant at 1180 K.When the temperature exceeds 1180 K,the reaction rate constant drops sharply until the end of the reaction.This is a one-step synthesis of vanadium nitride The main nitridation zone.In order to study the performance advantage of vanadium nitride in steel,this paper discusses the structural characteristics and application of nano vanadium nitride.By analyzing the characteristic parameters such as unit cell parameters,crystal area,unit cell volume,atomic number and atomic spacing of nanometer grade vanadium nitride particles,the number of particles,the number of particles,the number of surface atoms and the number of surface cells Relationship.The basic parameters of vanadium nitride nanostructures were determined by the above basic parameters,and the optimal nanoscale scale of nanometer nitriding was simulated by the surface effect,small size effect and macroscopic quantum tunneling effect of nano-particles.In order to ensure the stability of vanadium nitride,and to ensure the reaction activity of vanadium nitride crystals,we must consider the best comprehensive two nanometer scale,so in theory to determine the optimal nano scale of vanadium nitride should be about 200nm,but the final determined according to different structure and different combination of parameters of vanadium nitride.With the production practice,more in-depth study.