Abstract: In a process for refining molten metal selected from the group consisting of magnesium, copper, zinc, tin, and lead comprising the steps of:1. feeding the molten metal into a refining zone;2. providing a gas injection device submerged in said molten metal comprising (a) a shaft fixedly attached to a vaned rotor at its lower end, (b) a stationary sleeve surrounding said shaft, and (c) a passageway for conveying and discharging refining gas into the molten metal running the length of said gas injection device;3. introducing refining gas into the upper end of said passageway under sufficient pressure to be injected into the melt;4. withdrawing the spent refining gas and the dissolved gases released by the metal while collecting other non-metallic impurities in a slag layer on the surface of the molten metal; and5. withdrawing the refined molten metal from said refining zone.

Abstract: A vessel adapted for maintaining metal in a molten state comprising, in combination:A. an insulating refractory shell impervious to molten metal;B. a lining for a major proportion of that interior surface of said shell, which will be below the surface of the melt, said lining comprising graphite or silicon carbide blocks, which are free to expand in at least one direction in response to the application of heat; andC. at least one heating means disposed within any of the blocks.

Abstract: An externally heated cast iron vessel, intended for containing a reactive molten metal, such as aluminum, is made resistant to attack by the molten metal, thereby increasing its useful service life and minimizing contamination of the melt, by lining the inside of the cast iron shell with a plurality of inert self-supporting, refractory plates, of for example, graphite, in such manner that the plates are free to move along their joints as well as relative to the shell upon thermal expansion, and permitting the molten metal to penetrate behind the lining through the joints and crevices therein opened by thermal expansion, thereby producing a refractory layer, in situ in the space between said lining and the inside surface of said cast iron shell, comprising a solid (FeAl.sub.3) reaction product of iron and said molten metal.

Abstract: An externally heated cast iron vessel, intended for containing a reactive molten metal, such as aluminum, is made resistant to attack by the molten metal, thereby increasing its useful service life and minimizing contamination of the melt, by lining the inside of the cast iron shell with a plurality of inert self-supporting, refractory plates, of for example, graphite, in such manner that the plates are free to move along their joints as well as relative to the shell upon thermal expansion, and permitting the molten metal to penetrate behind the lining through the joints and crevices therein opened by thermal expansion, thereby producing a refractory layer, in situ in the space between said lining and the inside surface of said cast iron shell, comprising a solid (FeAl.sub.3) reaction product of iron and said molten metal.

Abstract: A process for removing alkali metal impurities from molten aluminum while avoiding the emission of environmentally harmful gases and fumes. The process comprises introducing a sparging gas comprising a mixture of an inert gas and a gas selected from the group consisting of chlorine, fluorine, halogen-containing compounds and mixtures therefor into unalloyed molten aluminum while maintaining the concentration of halogen in the sparging gas at a value intended to selectively halogenate the alkali metal impurities at a sufficiently high utilization such that the concentration of chloride in the effluent gas is maintained below a predetermined permissible limit.