REMOVAL OF LEAD AND ANTIMONY FROM LIQUID COPPER BY Cu_2O OR CuCl-BASED FLUXES BETWEEN 1423 K AND 1573 K

摘要

The partition ratios of lead and antimony between liquid copper and MgO saturated Cu_2O-CaO-SiO_2 flux and their removal rate by using CuCl-based flux were measured between 1423 K and 1573 K.rnFor Cu_2O-CaO-MgO_(satd) system, the partition ratio of Pb was not affected by the CaO content at 1573 K, while that of Sb increased with increasing CaO content. The maximum value was 160 at the CaO content of 15.4 mass%. For Cu_2O-CaO-SiO_2-MgO_(satd) system, two liquid phases of calcium silicate rich phase and Cu_2O rich phase were observed at 1573 K. The partition ratios of Pb and Sb between calcium silicate phase and liquid copper depended on the (mass%CaO)/(mass%SiO_2) ratio. When the (mass%CaO)/(mass%SiO_2) ratio increased, the partition ratio of Pb decreased and that of Sb increased.rnFor CuCl flux, the removal of Pb from liquid copper at 1473 K was possible, and a relatively low concentration could be reached. Moreover, most of lead as metal chloride vaporized from flux. For the removal of antimony from liquid copper at 1423 K, it was difficult by CuCl flux, and the removal ratio was approximately 20% for 75 minutes. However, the addition of CaO or Na_2CO_3 to CuCl flux was relatively effective to remove antimony, and the concentration of antimony reached a relatively low value after 15 minutes by using CuCl-CaO or CuCl-Na_2CO_3 fluxes. Moreover, a small part of antimony as chloride vaporized from flux.