A study on recovery of alumina grains from spent vitrified grinding wheel

About one-third of a grinding wheel is required for clamping. This portion remains unusable after the grinding wheel is consumed. However, this portion has virgin abrasives which can be used for grinding. The challenge is to recover the grains from the spent wheel, segregate the grain from the bond and to take stock of the property changes that might have happened during vitrification. If these can be done effectively, then the grain, initially declared as waste, can be used for re-manufacturing of grinding wheels. This paper describes methods to regenerate the grains from spent vitrified grinding wheels and indicates how the property can be characterized for reusability of the recovered grits. Chemical separation method was employed to remove the bond from the grinding wheel. A modified ball milling method is proposed to overcome the normal issue of agglomerates faced in recovered grits. Scanning electron microscope images of standard and recovered grains show the presence of sharp edges. So, these recovered grains could be reused for making grinding wheels. Results indicate that the so-called waste grains are tougher and can be used as value-added material in resinoid and coated abrasives.