Refractories are used to contain thermal processes and provide protection for personnel and furnace structures. The refractory must possess several beneficial properties including resistance to various wear mechanisms inherent to the process, and thermal conductivity that suits the energy needs of the process. Historically, dense, high thermal conductivity refractories have been used as working linings to provide wear resistance and process containment. Secondary layers of less dense, more thermally insulating materials have been used to reduce heat flux through the lining.
It is also important to consider the decrease in greenhouse emissions that result from burning less fuel. Greater than 3.75 million metric tons of CO2 were emitted by aluminum production processes in 2000.3 The same 1 percent improvement in efficiency would result in a reduction of more than 96,500 MT of CO2.