a) Aluminium is produced by electrolysis of alumina using carbon as a consumable anode. A cell operates under the following conditions: Total current =250000A, total cell voltage =4.4V, current efficiency =96%, current density at the liquid aluminium cathode =6000A/m2, density of molten aluminium =2270kg/m3 (i) How much aluminium is produced per cell in 24 hours, give your answer in kgs ? [4] (ii) If the metal is not tapped, by how much does the level of molten aluminium rise in 24 hours? (iii) What is the specific energy consumption (kWh/kg Al)? [2] (iv) What are the main gaseous emissions and how can they be controlled? [2] [2]