Recycling of Bag House Dust from Foundry Sand

Non-metallic foundry waste is generally composed of spent green sand, core sand, and dust collected in the ventilation bag-house systems of the foundry facility. Currently, practices exist for the recovery of sand particles from green sand and core sand at the expense of the other constituents via combustion or degradation. However, new methods are necessary to extract values other than sand from the bag-house dust material. This is important, because the dust of composed of as much as 50 weight percent non-sand recoverable materials, such as coal and clay. This research evaluates the potential to beneficiate bag-house dust material by way of froth flotation. The coal constituent of the dust was extracted at grades near 60 weight percent and recoveries near 70 weight percent. The clay constituent was extracted at grades near 30 weight percent and recoveries near 40 weight percent.