MetallurgyHard
Question
The major role of fluorspar (CaF2) which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite (Na3AlF6) is :
Options
A.as a catalyst.
B.to make the fused mixture very conducting.
C.to lower the temperature of the melt.
D.to decrease the rate of oxidation of carbon at anode.
Solution
Na3[AlF6] being ionic provides ions, thus increases the conductivity of the mixture and lowers its melting point (impurity lowers the melting point of the melt).
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