FIRE REFINING OF CRUDE COPPER BY FLUXES (2ND REPORT): REFINING OF CRUDE COPPER BY Na₂SO₄ AND CaO-Na₂SO₄ FLUXES.

Thermodynamic and kinetic studies on the removal of Va elements (As, Sb) from molten copper using a CaO-Na//2SO//4 flux were carried out. The distribution coefficients of As and Sb between the flux and molten copper were obtained at 1473 K. Although the values of As distribution coefficients in a CaO-Na//2SO//4 flux were smaller than those in a Na//2CO//3 flux, they were sufficiently high to consider its use as a flux for As in refining. The oxygen potential dependence of the As distribution coefficients suggested that the dissolved species of As in the flux was in the pentavalent state. The removal rates of As and Sb were measured at different temperatures and oxygen potentials.