Prediction of product particle size distribution using batch grinding equation

Advancing the chemical engineering fundamentals

Particulate Systems (T2-3P)

PhD Gordana Matijasic
Faculty of Chemical Engineering and Technology, University of Zagreb
Department of Process Engineering
Marulicev trg 19
10000 Zagreb
Croatia

Ing Krunoslav Žižek
Faculty of Chemical Engineering and Technology
Department of Mechanical and Thermal Process Engineering
Marulićev trg 20
10 020 Zagreb
Croatia
Croatia

Prof Marin Hraste
University of Zagreb
Faculty of Chemical Engineering and Technology
Marulicev trg, 19
10000 Zagreb
Croatia

Keywords: grinding, particle size distribution, batch grinding equation

Mathematical description of comminution process implicates identification of a model which will enable an optimal design and process control. The conventional approach to the description of comminution process starts with an introduction of statistical functions: selection function and breakage function. By determining the mentioned functions it is possible to predict the particle size distribution of the comminution product using batch grinding equation.
Wet grinding experiments were conducted using mono- and polidispersed dolomite samples in planetary ball mill. Dolomite size domain was discretized in twelve geometric size intervals (root2 basis). Selection function and breakage functions were derived experimentally, grinding each size interval independently. Obtained results were used in batch grinding equation.
Simple programme called GrindSIM was developed on the basis of well known Reid's solution for batch grinding equation. Analytical solution was also found using Laplace transform method. Numerical solution was derived using Runge-Kutta method. Simulation was performed on five different polidispersed dolomite samples using all three methods.
Results according to all three methods reveal very good agreement with those obtained experimentally for all used polidispersed samples. Knowledge of selection and breakage functions for one-size intervals enables prediction of particle size distribution for polidispered samples. Anyway, application of GrindSIM is limited to material properties and process conditions in which selection and breakage functions are obtained. The comprehensive use is possible if selection and breakage functions could be expressed in more general form involving process parameters and material properties dependence.

Presented Monday 17, 13:30 to 15:00, in session Particulate Systems (T2-3P).