MATERIAL FOR ALUMINUM REFINEMENT, ALUMINUM REFINEMENT, METHOD FOR PRODUCING HIGHLY PURE ALUMINUM AND ELECTROLYTIC CAPACITOR ALUMINUM, AND ELECTROLYTIC CAPACITOR ALUMINUM

摘要

PROBLEM TO BE SOLVED: To effectively remove peritectic-crystal-forming impurities and eutectic-crystal-forming impurities in aluminum refinement.

SOLUTION: The raw material used in aluminum refinement comprises a peritectic-crystal-forming element and boron in an amount which is larger by 5 to 80 ppm mass than the total chemical equivalent when the boron is calculated as a metal boride in which the metal is the eutectic-crystal-forming element. The raw material is melted in a melting furnace 1 to form a molten metal. In a reaction chamber 2A, the eutectic-crystal-forming element is reacted with boron in the molten metal to form a metal boride. The formed metal boride and the metal boride formed in the melting step are removed. In refinement chambers 2B, 2C, 2D, and 2E, highly pure aluminum freed of the eutectic-crystal-forming elements including unreacted boron is crystallized by segregation solidification.

COPYRIGHT: (C)2005,JPO&NCIPI