Molten Salt Electrolysis Preparation Of Gadolinium, Yttrium, And Iron Alloy Pilot Study

The topic is based on the project of JiaTong New Material Limited Company, the preliminary work of adding a little Gd and Y in the Nd-Fe-B permanent-magnet material. According to Chen Jiuchang's patented technology "New Nd-Fe-B Alloy" requirements, prepared alloy of Gd, Y and Fe by molten salt electrolysis. Because Gd, Y will not cause too much fluctuation to the performance of Nd-Fe-B permanent-magnet material, it can meet the requirement of product using,but Gd,Y are relatively cheaper, as to Nd-Fe-B permanent-magnet material, preparing RE-Fe alloy by molten salt electrolysis is more convenient and reasonable than preparing pure metals and may reduce the cost.It may prepare Gd-Fe alloy through molten salt electrolysis.Through the orthogonal experimental method, it determines the good technological conditions for the electrolysis temperature is about 1000℃, the cathode-current density is 8.5～10 A·cm^-2, molten salt composition GdF₃: LiF mass ratio of 90:10 or so in the experiment. Simultaneously we examine several factors, such as the composition of the molten salt, electrolytic temperature and cathodic current density , affect on electrolytic process. The craft is feasible after experiment proving and product analysis. The current efficiency and yield of rare earth respectively achieves above 65% and 85%.It also can prepare Y-Fe alloy through molten salt electrolysis. The average electrolysis temperature is 980℃, the average tank voltage is 10V, the cathode-current density is 9 A·cm^-2, the mass ratio molten salt composition GdF₃: LiF is 90:10. Compared by joining the high-purity Y₂O₃ and the rich yttrium oxide, we conclude that taking the high-purity Y₂O₃ as raw material, the yield of rare earth and the current efficiency is higher, the yttrium grade in the alloy is about 75% and the current efficiency may achieve above 65%.Moreover, Gd-Y-Fe ternary alloy is also attempted to prepare through molten salt electrolysis. Although the craft is feasible, the current efficiency is somewhat low, the technical conditions are to be optimized.Finally, the carbon content analysis experiment of Gd-Fe alloy has been carried out. We preliminarily understand that the electrolysis temperature, current efficiency and oxide utilization affect on the carbon content, and carry on the related recycling experiment to waste Gd molten salt in the production. In the whole recovery process, the total yield of rare earth reaches 90.74%, and the quality of the molten salt and rare earth oxide meets the requirement.