Optimization of processing parameters of a ball mill refiner for chocolate

The aim of this work was to optimise the ball mill based refining process of chocolate, in terms of refining time and energy consumption. Experiments were planned following a central composite design (CCD), considering refining time (rt) and agitator shaft speed (as) as factors. The experimental variables measured were chosen from the main characteristics that describe unmoulded chocolate. A complete second order model was fitted to the experimental data. The most significant coefficients were that of energy consumption, iron content and particle size. Optimisation consists in a bound minimization of refining time using the desirability function. The optimum conditions calculated were as follows: 58 rpm for as and 38.5 min for rt. A control experiment carried out in the optimised conditions to corroborate the results obtained, confirmed calculated expectations of response variables. In conclusion, the study enabled to identify new working conditions for the ball mill considered, rising output from 109 kg/h to 156 kg/h, with a 43% increase in productivity.