Influence of throw and compression ratio on particle shape-- A full scaleinvestigation and laboratory tests

摘要

The machine parameters of throw and eccentric speed affect the particle shape. Their influence on par-ticle shape is however not fully investigated. Preliminary tests on a full-scale crusher had shown certain trends in regard to the flakiness of the prod-uct (Fig. 1). These effects were investigated in detail by means of a series of piston-and-die tests, followedby modelling of the laboratory data. An empirical model of a crusher was developed which links the prod-uct size distribution and the shape of the particles to operating parameters. The simulator producedtrends which were similar to the full-scale data. The throw and eccentric speed affects the utilised compression acting on the rock/rock-bed. This paperpresents a method suitable for characterizing the compressive breakage behaviour of rock materials dur-ing form conditioned compression. In this method, size reduction is primarily related to geometric com-pression. The method provides a complete description of the breakage characteristics of the tested rockmaterial when compressive crushing is employed. The results can be used for modelling and simulationpurposes in the design of crushing equipment or crushing plants. A novel approach to optimise form conditioned crushing in order to achieve an acceptable particle sizeand shape is presented. The paper concludes that inter-particle breakage in combination with high compression ratio is bene-ficial for the particle shape. The full scale tests support this since an increase in throw imprOSies particleshape for particles subjected to inter-particle breakage.