Influences of Na₂O and K₂O Additions on Electrical Conductivity of CaO-SiO₂-(Al₂O₃) Melts

Abstract

The present study investigated the influences of Na₂O and K₂O on the electrical conductivity of CaO-SiO₂-(Al₂O₃) melts by the four electrode method. From the experimental results, it was found that the temperature dependence of electrical conductivity obeys the Arrhenius law. As adding Na₂O or K₂O to CaO-SiO₂-(K₂O) melts, electrical conductivity monotonously decreases. Meanwhile, Na₂O bearing melt always has a larger value of electrical conductivity than K₂O bearing melt when the compositions are the same. By substituting K₂O for Na₂O, the mixed alkali effect occurs that electrical conductivity first decreases and then increases with the substitution amount of K₂O. Furthermore, the mixed alkali effect is more evident for melts with Al₂O₃ than that without Al₂O₃.