Wet milling is a key production operation that is utilised to control particle size distribution (PSD) in slurry materials. The optimisation and control of milling is fundamental as the PSD ultimately impacts its rheological properties, the industrial performance and the chemical and thermal stability of the final products performances. A common problem in formulated products manufacturing arises when a variety of equipment technologies and scales is utilised. This makes process and product optimisations challenging and time consuming.
A typical configuration in wet milling are rotor-stator systems with grinding beads. The aim of this project is to develop a frame for the study of material flow and energetics for the grinding media considering different operating conditions and equipment scales. Reports of experimental work assessing the performance and the quality of the output fractions are numerous, but they lack in describing the fundamentals of collisions and the interplay of the different phases of the system. To shed some light into the system a dual synergetic numerical modelling is proposed in the framework of this project to extract the flow velocity, power draw and impact energy. On one hand, the Discrete Element Method (DEM) will be used to simulate the grinding media, flow kinematics and energetics. On the other hand, the computational fluid dynamics (CFD) combined with population balance modelling will be used to investigate fluid flow within the equipment configurations. A better understanding of the operation of mills will ultimately result in better process control, minimization of material losses, and a reduction of necessary experiments / out-of-spec material. The numerical results will be validated with experimental data obtained with several techniques. PEPT (Positron Emission Particle Tracking) and PIV (Particle Image Velocimetry) for flow studies. Techniques such as PSD zeta potential, acoustic and rheological measurements for physical characterisation.