Study On Simulation Calculation Of Internal Hydrogen Adsorption In WO₃ And Hydrogen Reduction Technology

By hydrogen reduction of tungsten oxide ultrafine tungsten powder in coarse and fine phenomenon,can not effectively control the morphology and particle size of tungsten powder,for tungsten oxide hydrogen reduction process dynamics research compare deficient,and difficult to use the means of laboratory study on the dynamic mechanism of effective,based on this,this article explores the hydrogen using density functional theory algorithm in WO terminating surface of WO₃(001)surface of the adsorption behavior of internal,using CASTEP module structure optimization and energy calculation,explore the hydrogen in WO₃ structure change and the energy change of the adsorption occurred.At the same flow rate,hydrogen reduction experiments were carried out at different hydrogen flow rates and reduction temperatures.XRD analysis and FE-SEM detection were carried out on the products.The effects of hydrogen partial pressure and reduction temperature on the microstructure of particles in the process of hydrogen reduction of tungsten were analyzed,and the following conclusions were drawn:(1)WO termination on WO₃(001)surface W_5c can not adsorb hydrogen atoms,but can adsorb hydrogen atoms on W_4c,hydrogen can adsorb on the oxygen atoms WO termination on WO₃(001)surface for isotopic adsorption and heterotopic adsorption,and H₂·O_2c and H·O_1c are respectively constructed in the original model.In the optimized structure,H₂·O_2c may change,but H·O_2c does not,and H·O_2c is more stable.When one of the adsorption points of heterotopic adsorption is selected on tungsten atom,H·W_xc(X=5,6)is constructed.In the optimized structure,H·W_xc will lose hydrogen atoms and finally become H·O_2c and W_xc.(2)The adsorption energy of hydrogen on the WO termination surface of WO₃was 18.116 Kcal/mol for isotopic adsorption and 14.116 Kcal/mol for heterotopic adsorption on the WO termination surface of WO₃.The isotopic adsorption energy was higher than the ecotopic adsorption energy,so the adsorption energy of hydrogen on the WO termination surface of WO₃ was 14.116 Kcal/mol.The adsorption energy of hydrogen on the WO terminating surface of WO₃ is 15.093 Kcal/mol,and the adsorption energy of hydrogen on the WO terminating surface of WO₃ is higher than that on its internal.(3)Hydrogen partial pressure,reduction time and reduction temperature can affect the morphology of tungsten powder.Increasing the reduction temperature and prolongation of reduction time can inhibit the phenomenon of clamping in tungsten powder.Very low hydrogen partial pressure and high hydrogen partial pressure are conducive to the preparation of fine and uniform tungsten powder.In the process of hydrogen reduction of xavellite,the brown tungsten oxide phase will appear.At 750?,the purple tungsten oxide phase will appear in the process of reduction.At this time,the rod tungsten powder will also appear in the product.In the process of hydrogen reduction of xavellite,the brown-tungsten phase will appear.At 750?,the purple tungsten phase will appear in the process of reduction.Yellow tungsten oxide can be used as a raw material for the preparation of uniform ultrafine tungsten powder,When the reduction temperature is 700?and the flow rate of hydrogen is 100 m L/min,the microstructure of tungsten powder is basically inherited from that of yellow tungsten oxide.