THE AUTOGENOUS FINE GRINDING KELSEY AXIAL DISPLACEMENT (KAD) MILL

摘要

The marginal improvements which continue to be made to fine grinding practices have exposedrnthe limits of conventional technologies and highlighted the need for a radically new approach. Thernpatented autogenous Kelsey Axial Displacement (KAD) Mill design consists of a rotating sphericalrngrinding chamber, which shares the same spherical centre as the shaft-mounted counter-rotating discrnassembly. The axis of the disc assembly can be inclined to the axis of the spherical grinding chamberrnby pivoting the disc shaft about the common spherical centre. The inter-particle energy transferrnrequired for breakage results from particle velocity differentials created by the discs intercepting thernrotating mass. Particle size reduction is concentrated in high shear zones, which envelop the outerrnsurface and periphery of the discs.rnThis paper traces the development of the KAD Mill from pilot to commercial scale. Pilot work coversrna range of minerals including magnetite, calcite, dolomite, barite, limestone and talc. Test resultsrninclude open and closed circuit operation in wet and dry modes. Conventional milling constraintsrnand energy consumption issues are addressed while new dimensions are added to the feed size rangernacceptable for wet and dry grinding to fine and ultra-fine sizes.