Integrated Desalination and Primary Aluminium Production

Primary aluminium is produced increasingly in regions where there is a scarce supply of clean and fresh water. A self sustainable, secure supply of fresh water is of strategic importance for aluminum smelters. Desalination plants can be installed in combination with gas-fired power plants, and it is shown that part of the natural gas consumed for production of water in the desalination process can be replaced with waste heat from the aluminium smelter pot gas. Besides, installation of heat exchangers allows a significant downsizing of Gas Treatment Centers as well as improved control of stack fluoride emissions. It is shown that a compact, robust double-effect desalination plant can provide the water required during predicted variations in water consumption and profitably use wasted heat for a typical AP40 smelter. The corresponding calculated cost of water is comparable to the cost of water available commercially.