Die Cast Parts,Copper Die Casting Parts,Die Casting Aluminum Cookware,Aluminum Alloy Die Casting Power Tools Ningbo Zongchi Machinery Technology Co., LTD , https://www.nbdiecastservice.com
Purification of rare earth metals by molten salt extraction
Certain rare earth metal mixed molten salt in contact with a high temperature, changing the metal O, N, H and other impurities in the partition between the molten metal and achieve the purpose of removing gaseous impurities. According to Japanese patents, rare earth metal lanthanum extracted with LiF, CaF 2, etc. can meet the requirements of magnetostrictive materials. In the above second purification method, DyF 3 is added for remelting and decalcifying, and in addition to consuming excess calcium, it is also a process of extracting molten salt, and the purpose of purifying impurities is achieved, and the oxygen content is reduced by 50%. Carlson ON et al. [17] used YF 3 -C a Cl 2 and YCl 3 as molten salts to perform molten salt extraction on the intermediate alloy during the molten salt extraction process of the intermediate alloy during the preparation of the metal ruthenium process. Finally, a metal ruthenium having an oxygen content of 0.015% and a nitrogen content of 0.002% was obtained (the metal ruthenium prepared by the molten salt extraction has an oxygen content of 0.12% to 0.25% and a nitrogen content of 0.015%). Spedding F·H· et al. [13] heated the metal ruthenium with C a F 2 and Ca at 1500 ° C for 15 min, cooled and slag, and then vacuum smelted to obtain an oxygen content of 0.936%. Nitrogen 0.04%). The Beijing Research Institute of Nonferrous Metals has carried out the test of preparing high-purity metal lanthanum by molten salt extraction method. The crude metal lanthanum, Ca and lanthanum fluoride are placed in a reduction furnace for reduction, and the purity of bismuth and high purity bismuth can be obtained at the same time. And according to the state of crystallization, the two are separated by hand selection, wherein the common ruthenium has a high crystal content due to high impurity content, and the high purity ruthenium is finely crystallized.
References
17 , Nagai H, et al. Matall Trans, 1978, 9B: 25 to 28