METHOD OF NIOBIUM REFINING Russian patent published in 1998 - IPC

FIELD: metallurgy; may be used in production of materials of high purity for atomic power engineering, electrical engineering, chemical machine building, in particular, method of niobium refining by multiple electron-beam remelting into mold with ingot pulling and electromagnetic mixing of melt. SUBSTANCE: at least one of remelts, excluding the last, is carried out by successive building-up of metal portion. After building-up, each portion is subjected to soaking with simultaneous treatment with electronic beam and electromagnetic mixing and upon attainment of the preset degree of metal refining, next portion of metal is built up. Height of built-up portion amounts to 10-15% of mold diameter. Duration of soaking of each portion is not less than 3 min and specific power of electronic beam during soaking is 0.5-1.5 kW/sq. cm of mold cross-section. EFFECT: higher degree of refining and homogeneity of metal, and increased process technical-and-economic index. 7 cl, 1 tbl