Calcium is obtained by electrolysis of a fused mass consisting six parts $\mathrm{C}\mathrm{a}\mathrm{C}{\mathrm{l}}_2$ and one part $\mathrm{C}\mathrm{a}{\mathrm{F}}_2$ at about ${700}^{\mathrm{o}}\mathrm{C}$ in an electrolytic cell made of graphite which acts as anode and a water cooled cathode of iron.
$\mathrm{C}\mathrm{a}\mathrm{C}{\mathrm{l}}_2\mathrm{}\rightleftharpoons \mathrm{C}{\mathrm{a}}^{2+}+2\mathrm{C}{\mathrm{l}}^{-}$
At anode: $2\mathrm{C}{\mathrm{l}}^{-}\to \mathrm{C}{\mathrm{l}}_2+2{\mathrm{e}}^{-}$
At cathode: $\mathrm{C}{\mathrm{a}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{C}\mathrm{a}$