Process for refining magnesium, copper, zinc, tin and lead

摘要

The refining gas, for example nitrogen, is injected into the molten metal by means of an injection device comprising a rotor (1) with fins (2), driven by a vertical shaft (3) surrounded by a stationary sleeve (4). The gas is introduced through an annular passage arranged between the shaft and the sleeve and comes out by virtue of a clearance provided between the rotor and a grooved stator (11). In the molten metal, the rotor creates currents which make the bubbles of refining gas travel outwards and downwards, and this improves the gas-metal content. Since the gas is preheated in the sleeve (4), the bubbles do not expand within the metal and remain small. IMAGE