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The development of viable techniques for the recycling and reclamation of metal-matrix composites (MMCs) is critical to the commercialization of these advanced materials. The recycling of both MMC wrought alloy (6061) scrap and foundry alloy (highsilicon) returns has been studied. The MMC extrusion alloy scrap has been recycled back into direct-chill cast logs and the resulting billet has been tested to determine whether the composite properties are degraded by repeated recycling. Similarly, fluxing and degassing techniques have been developed 50 that MMC foundry alloy gates and risers produced in shape-casting may be recycled back into useful castings. These fluxing and degassing processes have been tested commercially. Ultimately, when either type of MMC scrap can no longer be recycled, the alumina particles in the wrought alloys or the silicon carbide particles in the foundry alloys may be removed by common salt or other fluxing techniques. Rotary salt furnace technology has been shown to be effective for this approach, and the results of large-scale trials are reported here.

Scrap rate, throughput, alloy recovery and raw materials are all areas of the casthouse which usually get substantial attention as means of either increasing profits or reducing costs. However, furnaces, which are often overlooked by the casthouse, can also deliver surprisingly high savings. Moreover, these potential savings can only magnify as energy costs and pressures to reduce carbon footprint increase. This paper gives an insight into where savings can be achieved by a casthouse with proper furnace operation. Knowledge of how a furnace should be operated is often neglected but as this paper tries to highlight, developing this knowledge can be extremely worthwhile.

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