Kis, Piroska B.

Mihálykó, Csaba

Kis Piroska B.

Mihálykó Csaba

University of Szeged

Investigation of the asymptotic behaviour of a closed-circuitgrinding systemPiroska B. Kis and Csaba MihálykóA discrete mathematical model for a grinding mill-classifier system expressed in the formof delay difference equations was developed. In the model, the mixing of the material to beground by the axial dispersion model, the breakage kinetics by the first order breakage law,and the classifier by a usual classification function are described.Closed-circuit grinding system, characterised by external classifier can be used successfullyto reduce the energy consumption, and at the same time, to prevent the ’over-grinding’ of theproduct. However, because of the continuous recycling of the coarse material, such a systemmay exhibit instabilities in the form of oscillations and overloading of the mill, therefore a moredetailed analysis of the system behaviour is required.The closed-circuit grinding system considered in this paper is as follows: the fresh materialto be ground enters the mixer and it mixed perfectly with the still coarse material recycled fromthe classifier. Travelling through the mill, the particles are continuously ground and mixedbecause of their stochastic motion. The ground material is sent to the classifier, from that thefine component is removed as the finished product, while the coarse material is recycled.The discrete model developed is the basis of the computer simulation. The whole grindingprocess can be observed, statistical characteristics of the ground material can be calculated atany moment of time with the aid of simulation. The influence of the parameters of both themill and the material to be ground can be investigated via simulation.At this time, we focus on the asymptotic behaviour of the model. For that reason the setof model equations is written in matrix form. The asymptotic behaviour of the grinding mill-classifier system was investigated by means of the eigenvalues of matrices, and the influenceof the classification was examined via numerical experiments.69

Investigation of the asymptotic behaviour of a closed-circuit grinding system : [abstract]

http://acta.bibl.u-szeged.hu/59771/1/cscs_2004_069.pdf

Investigation of the asymptotic behaviour of a closed-circuit grinding system

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