| 摘要 |
<p>8630-3 PROCESS FOR REFINING MOLTEN METAL 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. maintaining a protective atmosphere above the surface of said molten metal at a greater than atmospheric pressure, thereby preventing contact of the melt with air or atmospheric moisture; 3. 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; 4. introducing refining gas into the upper end of said passageway under sufficient pressure to be injected into the melt; 8630-3 5. preheating the refining gas by contact thereof with the hot walls of the passageway, whereby the gas is expanded, before being sub-divided into gas bubbles, to the point where thermal growth of said bubbles in the melt is substantially prevented; 6. directing the preheated refining gas to the vanes of said rotor of said gas injection device; 7. sub-dividing the refining gas into discrete gas bubbles by rotating said vaned rotor at a speed sufficient to create a circulation pattern in the molten metal such that the gas bubbles are transported substantially radially outward with a downward component relative to their points of entry into the melt thereby coming into intimate contact with substantially the entire mass of molten metal in said refining zone, resulting in the removal of dissolved gases and substantially all non-metallic impurities from said melt; 8. 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; and 9. withdrawing the refined molten metal from said refining zone.</p> |
