The beneficiation of bauxite ore, used to produce aluminum and the subsequent refining of the aluminum to specific alloys and/or shapes, is an energy intensive process. Large amounts of heat energy (generated via electrical discharge in the primary process and from the burning of fossil fuel in the secondary process) are lost as a result of the insufficient thermal insulating properties of current refractory linings. As a consequence, the increased BTU value per unit of aluminum is accompanied by a greater use of energy generating resources, increased emissions, and an elevated the cost of the final metal product - in summary, a negative impact on the global competitiveness of U.S. aluminum producers. This project will develop an insulating refractory lining, suitable for use in hot processes for aluminum manufacture. The lining will allow for limited metal and flux penetration while offering an estimated 10 to 35 percent reduction in heat loss compared to conventional refractory linings. Phase I will investigate compounds and mixtures of compounds of the general formula (CaO)x(Al2O3)x in combination with aluminum penetration inhibitors as a prototype aggregate for forming a refractory monolith. The pore size distribution of the monolith will be altered to limit metal and flux penetration while improving the thermal insulating quality of the monolith.
Commercial Applications and Other Benefits as described by the awardee: The material should find use in the aluminum industry in the working lining of hearths, upper and lower sidewalls, belly band areas, roofs, chip melters, troughing, transfer ladles, and over-the-road crucibles. In addition, the material should find use in float glass lines (molten tin contact) and the rotary kilns used to produce cement and lime (another area of intense energy use)
