GB554685A - - Google Patents

Abstract

554,685. Melting metals; alloying. WEBB, G. W., and PROCTOR, W. F. Oct. 13, 1941, Nos. 13159/41 and 2225/42. [Class 82(i)] [Also in Groups XI and XXIII] Metals, e.g. aluminium, are melted in a bath of molten inert material having a lower melting point than, and a different specific gravity from the metal, and a boiling point above the melting point of the metal, e.g., in a salt bath, which may include fluorides. A casing 1 contains a hopper 2 with refractory bars 3 to receive ingots from pre-heating chambers 4. The lower end of the hopper opens into a trap box 9 with a flanged valve seating which receives an inverted cup valve operated by a handle 13. Electrodes 15 are arranged in the hopper for heating the salts above the metal, and electrodes are arranged for heating the salts in the casing 1. The temperature may be controlled by a thermostat. The metal discharge tube 11 may also be provided with a thermostatically controlled heater. The outlet end of the hopper may be modified to provide a measuring chamber by which a measured quantity of molten metal is discharged at each operation ofthe valve. The valve seal may be of lead to avoid attack on the valve by aluminium. The lead seal may be omitted if the valve is of a material impervious to aluminium, and is sufficiently deep. In a modification in which the metal, e.g., magnesium or its alloys, is lighter than the salt, the hopper is inverted and the metal floats upwards towards the discharge passage. Instead of ingots, swarf may be melted, in which case it is fed from a container by a pusher, or conveyer, or through a tube with valve. In another modification, metals may be mixed in the hopper to form an alloy, by means of a helical rotary mixer.