Modeling and simulation of gravitational solid–solid separation for optimum performance

• Published in: Powder technology 2013-05, Vol.239, p.337-347
• Main Authors: Rotich, Nicolus, Tuunila, Ritva, Louhi-Kultanen, Marjatta
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical engineering; engineering; Exact sciences and technology; glass; Gravitational classification; gravity; mathematical models; Miscellaneous; Modeling; screening; separators; Simulation; simulation models; Solid-solid systems; Solid–solid separation; systems engineering
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2013.01.056

Reichert cone separators have been used for classification in the mineral processing industry for over six decades now. However, their application has always been limited to wet processing. In this paper, we assess the potential of their modification and use in gravitational dry solid–solid separation. A theoretical model was formulated, describing the motion of particles along inverted cone-shaped series of inclined screens with increasing aperture sizes under the force of gravity. A mathematical model to quantify the rate of separation was also suggested based on the theory. Three important design parameters were proposed to aid the actual engineering design of the system. The two models were test-run by numerical simulation under computer-generated, uniformly distributed random sized particles on a hypothetical 0.254m radius cone, from which a theoretical screening rate of 32.52g/s was achieved. The simulations were verified experimentally by designing a prototype system of equal effective screening area, and with equal input masses of glass beads, an overall screening rate of 23g/s and a maximum separation efficiency of 66.4% was achieved. This study showed that a change in momentum of a heap of dry particulates controllably released on a perforated inclined surface is enough to cause sufficient separation of particles (~66.4%). The rates of separation achieved depend heavily on the inclination, particulate momentum, screening area, and particle sizes and shapes. [Display omitted] ► We have described the motion of particles along inclined screens under gravity. ► Dry particles can be separated gravitationally on an inclined perforated surface. ► We suggested a mathematical model to quantify the separation rate. ► We proposed three parameters for equipment design. ► We have also tested the models experimentally and we have reported the results.