| Removal of impurities such as antimony, arsenic, tin, lead and bismuth from molten blister copper by cryolite flux has been investigated in order to develope a new pyrometallurgical copper refining process. A 300g of molten blister copper in which Cu₂O was dissolved as an oxygen source was treated with cryolite. Experiments were carried out in argon atmosphere at 1200℃. At added oxygen of 0.5wt. %, antimony, tin and arsenic contents in molten blister copper decreased rapidly from 0.12wt.%, and 0.113wt.% to 6.0×10^(-3) wt.%, 1.4×10^(-3) wt.% and 1.0×10^(-3) wt.%, respectively. The cryolite flux, however, had only a moderate effect on the removal of lead whereas virtually no effect on the removal of bismuth. A brief thermodynamic analysis was carried out to estimate the solubility limits of impurity oxides in molten blister copper and the experimental results were well explained by the thermodynamic analysis. |
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