The carbon plant produces approximately 330,000 tonnes of anodes per year for use in the potlines.
Anodes are made from petroleum coke, recycled butts and pitch. Butts are the residual carbon part of spent anodes. The coke and butts are crushed and screened before different quantities are mixed with pitch at about 180°C and formed into “green” anodes. Each anode weighs about one tonne. The “green” anodes are baked at about 1,200°C before being used in the electrolytic cells.
The production of one tonne of aluminium requires about 0.5 ton of anodes. Approximately 75,000 tonnes of butts per year will be recycled at the plant.
Both the paste plant and the anode baking plant are equipped with state of the art fume treatment plants to minimize emissions.
The anode service plant consists of the bath cleaning plants (BCP’s) and the anode rodding plant (ARP). Spent anodes are pre - cleaned in the BCP’s. Bath residues are recycled to the potline and butts are recycled to the paste plant. Anode hangers are prepared in the ARP and checked before new baked anode blocks are attached. The complete anode assemblies are then returned to the potline.