PURPOSE: To deposit a high purity metal contg. no impurities on a hearth by putting molten metal contg. impurities into the furnace having a gaphitic hearth and cooling the hearth part.
CONSTITUTION: Flow pipes 5 for a cooling medium each provided with a high aluminous refractory brick 3 on the side wall, having many graphite blocks 4 laid in the bottom, and having a notch 11 in a part of each block with an expansion absorbing member mounted therein are beforehand provided. The melt of impure Al contg. impurities such as Fe is charged through an inlet 9, and while the melt is kept stired with a stirrer 8, a refrigerant such as water is run into the pipes 5 to cool the blocks 4. The Al 15# of high purity contg. no impurities deposits from the impure Al on the layer 3 and accumulates on the layer 3. When 40W50% of the molten Al charged into the furnance deposits as high purity Al, the remaining impure molten Al is discharged from the furnace by tilting the furnace, whereafter the high purity Al on the graphite hearth 3 is melted by heating with a burner and is thus removed.
MATSUOKA SHIROU
HASHIMOTO TAKASHI
KAWAKAMI HIROSHI
SEKI YOSHINORI
