Discrete model for analysis and design of grinding mill-classifier systems

Discrete mathematical and computer models are developed for the simulation of grinding mill-classifier systems on the basis of distributed parameter models of continuous grinding processes. The discrete model is derived from the partial integro-differential equation describing axial mixing and breakage of particles in grinding mills. The convective flow and axial dispersion in the mill are modeled as particle size-dependent processes, while the recirculation line is described as plug flow of the classifier rejected material involving also some time delay. The resulted set of recursive linear algebraic equations was the basis of computer model developed in MATLAB environment. The capabilities of the computer model are demonstrated by presenting and analyzing results obtained by numerical experiences. The influence of both the kinetic and process parameters of the mill-classifier system on the size distribution of the ground material as well the dynamic behavior of the system are presented and analyzed. The computer model is suitable for designing the configuration and operational conditions of both open- and closed-circuit grinding mill-classifier systems efficiently.