Desulfurization experiments were carried out with molten copper alloys by using a Na2CO3 flux in a 2 kg high freqency melting furnace to investigate the effects of alloying elements, melting atmosphere and melting temperature on the desulfurizing behavior of the flux. Sulfur distribution and desulfurization rate are affected by the contribution of alloying elements to the activity of sulfur in melts, the basicity of flux and the solidification temperature of alloys. The melting atomosphere has a large effect on sulfur re. moval: covering melt with charcoals or using a carbon crucible accelerates the desulfurizing ability of Na2CO3. The maximum desulfurizing ability was obserbed at 1, 473 K in the temperature range from 1, 423 to 1, 573 K. The reason is as follows: the sulfur removal is decreased at lower temperatures according to the temperature dependency of desulfurization equilibrium, and at higher temperatures by the vaporization of Na due to the reaction between Na2CO3 and carbon.
