Thermodynamics and Kinetics of Preparing Sponge Zirconium by Kroll Method
In this paper,in order to further optimize the process of preparing sponge zirconium by magnesium thermal reduction method(Kroll method),the effects of reducing agent Mg content,sublimation temperature and argon partial pressure on the reduction process are analyzed by calculating the Gibbs free energy change and reduction rate of ZrCl4 reduced by Mg,and the structural composition,impurity distribution and hardness changes of sponge zirconium products were studied.The results show that controlling the temperature of the sublimation furnace at 792℃and ensuring an excess of reducing agent Mg can reduce the types of metal chloride impurities entering the reduction furnace.The least amount of black powder can be produced when the average proportion of pAr is 0.25 and the corresponding reduction reaction rate is 17.9 kg·h-1.Cl,Fe,Mg and O impurity elements exhibit local aggregation in sponge zirconium.The aggregation sites of Cl and Mg elements correspond to the aggregation site of O elements.In addition,the highest hardness value of the sample is 112 HB.
万方数据
维普
