Removal and Recycling of Antimony from Liquid Copper by Using CuCl-CaO Fluxes at 1423 K

The removal behavior of antimony from liquid copper by using CuCl-CaO fluxes was observed at 1423 K. It was difficult to remove antimony from liquid copper by using only CuCl flux. However, the addition of CaO to CuCl flux was effective for the removal of antimony. The concentration of antimony decreased with time or with increasing CaO content. About 99.9 pct of antimony was removed from liquid copper at 15 minutes for CuCl-25 mass pct CaO flux. A part of antimony vaporized from flux to gas phase. The weight loss of antimony from metal-flux system increased with the addition of CaO to flux. The mechanism of removal and recycling of antimony from liquid copper was discussed based on the observed results. A small part of antimony in liquid copper was chlorinated by CuCl flux, and then the formed antimony chloride vaporized from flux. In the case of CuCl-CaO fluxes, antimony in liquid copper was first oxidized, and then the formed antimony oxide was chlorinated by CuCl. It was possible that this chlorination reaction resulted in the formation of antimony compounds with the low boiling points such as antimony trichloride. Finally, antimony vaporized from flux.