Dewatering of finely dispersed calcium carbonate-water slurries in decanter centrifuges: About modelling of a dynamic simulation tool

Finely dispersed suspensions are used as intermediate or end products in many processes in the chemical, pharmaceutical, and minerals processing industries. Continuously working decanter centrifuges are often applied for the separation or purification of the resulting suspensions. In order to minimise the experimental effort for dimensioning a centrifuge, mathematical models are required which describe the process adequately. The mathematical description of the cylindrical and conical part is needed to predict the build-up of finely dispersed cake in decanter centrifuges. This article presents a physically based computational model to predict the dynamic behaviour of decanter centrifuges. The method considers settling behaviour, cake consolidation, and sediment transport by means of material functions. The used material functions describe the behaviour of the slurry within the apparatus and are measured with well-established lab-scale centrifuges. Consideration of the cylindrical and conical part in the mathematical model allows for the investigation of the influence of different parameters (e.g. cone angle, length of cone, rotational speed, differential speed, etc.) on the process behaviour of decanter centrifuges. The presented dynamic model is validated by comparison with experimental data for an industrial-scale decanter centrifuge.