Before electrolysis of alumina, it mixed with cryolite $\left({\mathrm{Na}}_3{\mathrm{AIF}}_6\right)\text{ and }{\mathrm{CaF}}_2$ to

In the electrolysis of alumina it is mixed with cryolite $\left({\mathrm{Na}}_3{\mathrm{AIF}}_6\right)$and fluorspar $\left({\mathrm{CaF}}_2\right)$in the ratio 20 : 40 : 20. The function of cyolite and fluorspar is to decrease the fusion temperature of alumina and make it good conductor of electricity.