Technical note : the materials cycle

The term 'materials cycles' describes the total process during which raw materials are fashioned into materials for use in manufacture and subsequently the manufactured articles are returned to the earth, water and atmosphere as various kinds of 'waste'. Materials cycles are interconnected by energy cycles. Currently it is becoming imperative for the engineer to be aware of the total materials cycle, and to minimize the dissipation of materials and energy in fulfilling the technical and economic demands of industry. An example is given here of the energy budget of aluminium production, and how savings in energy use can be incorporated in new designs of plant which is to produce or use aluminium.