Continuous copper drossing of lead

摘要

A process for the continuous copper drossing of molten lead bullion is provided, the process comprising, establishing a column of molten lead having a hot top portion at a temperature of about 800 DEG C. to 1150 DEG C. and a bottom portion of substantially lower temperature of about 340 DEG C. to 425 DEG C. Approximately the middle portion of the molten lead is controlled at a temperature of about 750 DEG C. to 900 DEG C. to thereby provide a predetermined temperature gradient extending from the middle portion to the bottom portion controlled at about 340 DEG C. to 425 DEG C. The temperature of the top portion is controlled by induction heating and the temperature of the bottom portion by cooling coils containing a fluid coolant. The molten lead is fed continuously to the middle portion of the column while maintaining the temperature thereof at about 750 DEG C. to 900 DEG C. The molten lead is continuously withdrawn from the bottom portion of the column at a rate conducive to maintaining the desired predetermined temperature gradient between the middle of the container and the bottom thereof.