Optimizing the Moulding Properties of Recycled Ilaro Silica Sand

Effect of varying binders (bentonite and dextrin) and water on the properties of recycled foundry sand made from silica sand mined from Ilaro Silica sand deposit in Ogun State Nigeria and have been used in several cycles for production of cast iron was examined. The used sand was washed in hot water, dried and the sieved for grain distribution. Varying bentonite and dextrin contents were added together with water to portions of the silica sand and thoroughly mixed. The moulding sand properties (permeability, green strength, compatibility, shatter index and moisture content) of the recycled foundry sand were determined. It was observed that the recycled Ilaro sand (after several cycle of usage) has grain Fineness Index (GFI) of 50 and that it can still be reused by minimum addition of binders. It was concluded that the optimum green strength and permeability for the recycled sand was achieved when 12g of bentonite, 8g of dextrin and 12cm3 of water were added to 200g of recycled sand.