Inferential Sensor of Residual Moisture Content and Separation Efficiency Applied to Pilot-Scale Vibrating Screen

Chemical Engineering Faculty, Federal University of Uberlandia, Brazil

Abstract: Vibrating screening is still one of the main operations considering solid-solid and solid-liquid separation processes. Although it is an equipment of simple design and execution, the full description of a screening unit operation may be difficult to predict, considering that several operational variables can influence it. Therefore, the main objective of this work was to develop an inferential sensor to be used with an optimized control system in order to automate and improve the sieving process. Semi-empirical models were identified considering a pilot-scale vibrating screen by using a suspension of phosphate rock concentrate (with a density of 3.25 g/cm3 and average particle size of 95 µm), water, and xanthan gum. The experiments for obtaining the models followed a factorial design 3k and relate moisture content of retained solids and separation efficiency to g-force and solids concentration in the feed. The vibrating model was obtained by the disturbance in the rotation of the vibration motors and relates the g-force with rotation of these motors. The combination of the models was studied through simulation. The behavior of moisture content and separation efficiency was evaluated and an operation optimization was performed. For the studied range, the system worked properly, leading to g force to the best possible value, depending on operating conditions of the vibrating screen.