(70aj) Unique Applications of Fluidization for High-Volume Foundry Sand Processing

?Precision Sand Mold? casting processes have become one of the dominant aluminum engine-casting methods. Typically, a single process line will produce 60-160 engine blocks per hour, each block requiring a phenolic urethane resin-bonded sand mold weighing 200-400 kg. After casting, a novel technology can be employed to simultaneously heat treat the casting, remove the sand mold/cores, and thermally reclaim the sand. Sand is then cooled, classified, and transported to the core shop where it is re-used to make new precision sand molds. Many plants experience a greater than 90% re-use rate for their sands, and most recover sands at a very low LOI (loss on ignition).

Achieving a high rate of reliable sand processing, several foundries worldwide use 30 to 40 tonnes per hour of sand. At these sand usage rates, it is an economic necessity to reclaim sands successfully. The technology employed is composed of a high volume fluid bed thermal regeneration system (integrated with the heat treat system), vibratory sand conveyors, pneumatic conveyors, and fluidized bed cooler/classifiers. This paper will address the overall sand process, current equipment designs and operation, and focus on key technology developments both past and present.