Name the following:
(a) A metal which is liquid at room temperature.
(b) The process of heating an ore to a high temperature in the presence of air.
(c) The compound formed by the reaction between calcium oxide and silica.
(d) A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.
(e) Name an allotrope of a non-metal that allows electricity to pass through it.