| 摘要 |
<p>PCT No. PCT/FR94/00862 Sec. 371 Date Jun. 13, 1995 Sec. 102(e) Date Jun. 13, 1995 PCT Filed Jul. 11, 1994 PCT Pub. No. WO95/03434 PCT Pub. Date Feb. 2, 1995A process for obtaining aluminum of purity above 99.998%. A liquid aluminum raw material is subjected to a fractional crystallization to obtain prepurified aluminum crystals in a yield of between 50 and 80% and a liquid aluminum portion of lesser purity. The prepurified aluminum crystals are subjected to a three-layer electrolysis process in which the uppermost layer comprises a cathodic purified aluminum layer. The aluminum of purity above 99.998% is removed from the uppermost layer at a yield of above 90%, the aluminum having a total rare earth content of less than 100 ppb and a total content of U+Th of less than 20 ppb.</p> |
