Optimization Of Preparation Technology Of High-Purity Metal Terbium And Industrial Practice

Metal terbium has superconductivity and high ferromagnetism at low temperature,which can be made into new magnetic materials and superconducting materials,and plays an increasingly important role in the national economy.At the present stage,it is of great practical significance to study the preparation technology of metal terbium,which can make full use of China's abundant rare earth resources and turn the resource advantage into technical advantage.In order to solve the problems in the production of metal terbium,such as the excessive content of non-rare earth impurities,the low yield of primary direct reduction and the short average service life of tungsten crucible,the method of determining the main production process parameters and optimizing the auxiliary process parameters was used to find the key to solve the problems,so as to realize the high-efficient mass production of metal terbium.(1)The key process parameters are those which have great influence on the yield of metal terbium and the content of impurities in metal,such as argon pressure,reducing agent dosage,refining temperature and time,etc.The results showed that when argon pressure reached-0.07 mpa and-0.06 mpa,the primary reduction yield of metal terbium reached the peak.When the excess calcium in reducing agent was25.8%,the yield was 97.8%,reaching the highest value.Meanwhile,the contents of calcium and tungsten impurities in metal terbium could reach 0.24% and 0.036%respectively.In the secondary refining stage,when the heat preservation time was40 min and the heat preservation temperature was 1500?,the comprehensive indexes of metal terbium products obtained from the production were the most ideal.(2)Auxiliary materials include pot building process,water cooling grinding tool,material placing process,etc.It was found that on the basis of the original magnesia pot with a single particle size(2.0um),magnesia with a particle size of 0.5-2um was proportionally increased by about 50%,and the service life of the crucible was significantly improved.After replacing the steel plate with water-cooled mold,the content of impurity calcium in the metal was reduced to 0.12%,the content of impurity tungsten was reduced to 0.16%,and the content of impurity iron was reduced to 0.018%,all of which could reach the excellent quality index.The yield of the improved metal terbium reduction reaction increased from 96% to 98% when the reaction materials were placed according to the melting point and the metal calcium was crushed at the same time.In this paper,the key technological parameters and auxiliary materials and equipment in the production of metal terbium of our company were studied.and the optimum technological parameters were determined,which increased the reduction yield of metal terbium to more than 98%,reduced the content of impurity elements,and improved the average service life of tungsten crucible.