Question

Answer in one word: Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

Answer 1

Extraction of aluminium is done from Bauxite, a common ore of aluminium.

1. Cryolite ${\mathrm{Na}}_3{\mathrm{AlF}}_6$ is added to extraction of aluminium to decrease the melting point of alumina.

(i).The molten cryolite act as a solvent which reduced the energy costs in extracting aluminium.

(ii).The ions of aluminium oxide are allowed to move freely at low temperature.

Hence,cryolite is added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.