Optimization of closed underflow mini-hydrocyclones for separating sand from well water by two indices of mass efficiency and cut diameter using the Taguchi method: a case study of Mashhad, Iran

In this study, the Taguchi method was applied in order to design experiments and optimize the performance of mini-hydrocyclones by closed underflow for sand removal from well water. To optimize the hydrocyclones, two indices, mass removal efficiency and the cut diameter, were used. The first index analysis results showed that under the optimum conditions, the overall mass removal efficiency of solids will be up to 98.4%. An analysis of cut diameter data illustrated that under optimum conditions, the predicted cut diameter will be about 12.7 μm, while this diameter was estimated at about 16.3 μm under optimum mass removal efficiency conditions. The actual values of mass removal efficiency and cut diameter were determined at about 97.2 ± 1.1% and 14.5 ± 0.7 μm, respectively, for hydrocyclone manufacturing on the basis of mass removal optimum conditions. The use of the traditional estimation models such as Plitt, modified Plitt, Luz, and so on, which are applied for mining and mineral processing, illustrated that the estimated cut diameters were about 7.9, 8.4, 8.2, 0.45, and 2.33 μm, respectively. This estimation represented that these models are not suitable to predict the cut diameter of the hydrocyclone with closed underflow. Further investigation revealed that only the scale-increasing model could well predict a cut diameter of about 15.4 μm.