Investigation of (CaO)x(Al2O3)x for Thermal Insulation and Molten Aluminum Contact

75253S 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 cost of the final metal product. 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 investigated compounds and mixtures of compounds of the general formula (CaO)x(Al2O3)x, in combination with aluminum penetration inhibitors, as candidate aggregates for forming a refractory monolith. Energy savings greater than 35% was demonstrated theoretically. Phase II will optimize the physical traits of successful compounds and provide sufficient material for experimental trials in customer process vessels via the creation of a pilot production facility. Data collected from the pilot production facility will be used to design, engineer, and build a full scale production facility. Commercial Applications and Other Benefits as described by the awardee: The material should find use in the aluminum industry in the working lining of holders, 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), other non-ferrous metal applications, and the rotary kilns used to produce cement and lime (another area of intense energy use).