ROTOR SPEED - SIZE REDUCTION RELATIONSHIP IN A VERTICAL SHAFT IMPACT CRUSHER

Vertical shaft impact crushers (VSI), mainly used in aggregate production, are operated in mining industry widespread in the world. The VSI, which is used as a tertiary or quaternary cursher, is very well known in aggregate industry by its production of cubical particles and in mining industry by its fines generation. The particles fed into the crusher is accelerated by means of the rotor and directed to the walls of the crusher where a high velocity impact breakage occurs. The adjustable rotor speed allows to crush the material from different energy levels to obtain different product finenesses. In this study the size reduction performance of the crusher was assessed with respect to rotor tip speed rather than particle shape. Results showed that the product gets finer as the rotor tip speed increases and the optimum operating condition can be achieved by adjusting the capacity of the crusher