Factors influencing properties of carbon electrodes

Aluminium is obtained commercially from the Hall-Heroult Process, the electrolytic reduction of bauxite (aluminium oxide). The electrodes used are made from different types of carbon; the bulk of the electrode, known as the filler, is typically made from either a calcined-anthracite or petroleum coke, the particles of which are bonded together by the binder component of the electrode, which is usually coal-tar pitch. Large quantities of electrodes are consumed each year; attrition is by a variety of causes, and since there is no commercially realistic alternative to the Hall-Heroult Process, any means of reducing loss of electrodes would improve the economics of the extraction process. [Continues.]