On the use of grains recovered from spent vitrified wheels in resinoid applications

Vitrified grinding wheels are used in various end applications. They are easy to dress and have better mechanical properties. In general, grinding wheels are used till the stub portion. After usage, this stub portion is discarded as waste. Grains in this portion are fresh. Recovering and reusing the grain in the stub portion are both economically and environmentally beneficial. This work deals with the recovery and reuse of abrasive grains from vitrified brown alumina grinding wheel rejects. Grains are recovered using mechanical crushing processes. The recovered grains are used for production of resinoid cylindrical grinding wheel of 350 mm outer diameter. Performance of this grinding wheel was compared with standard grinding wheel of brown alumina grain in a CNC cylindrical grinding machine. The experiment was conducted by varying three feed rates (0.25, 0.5, and 1 mm/min). The trial wheel exhibits lower wheel wear and higher grinding ratio in all feed rates, without any loss in material removal rate. The difference in performance of the grinding wheel is correlated to the difference in toughness of the grains. It is shown that grains from vitrified rejects of brown alumina can be recovered and advantageously used in resinoid applications. This helps in reusing the otherwise wasted abrasive, thereby reducing pollution to the environment.