| 摘要 |
<p>PURPOSE:To separate and recover molten Al having high purity into the crucible below a refractory filter by putting Al scrap contg. Fe as an impurity into a crucible having said filter in the bottom, heating the scrap to a specific temp. to melt and pressurizing the inside of a furnace. CONSTITUTION:The graphite crucible 3 having opened top and bottom ends is set into an electric furnace 1 provided with a heater 1A. The refractory filter 22 made of ceramics or coke is attached to the open surface at the bottom end of the crucible 3 and the cylindrical graphite crucible 4 having the bottom is placed below said filter. The melt of the Al scrap contg. a harmful impurity such as Fe is put into the preheated crucible 3 and is heated to the temp. higher by 30-40 deg.C than the deposition temp. of the compd. composed of Al and Fe then the temp. is gradually decreased to the temp. at which the compd. composed of Al and Fe crystallizes or below. Gaseous N is simultaneously forced into the furnace through a supply pipe 10 and the inside of the crucible 4 below the filter 22 is evacuated by a suction pipe 12 to filter the pure Al by the filter 22 into the lower crucible 4. The crystallized impurity is allowed to remain on the filter 22.</p> |
