Abstract
The Magstream separation process, developed by Intermagnetics General corporation, offers an alternative method for both laboratory and plant mineral separations. It is based on the concept of using a fluid whose effective density is magnetically derived. The separator can be applied to both purely gravimetric separation of non–magnetic materials and magnetic–gravimetric separation of paramagnetic material.The separation density can be easily adjusted by changing the speed of rotation or process fluid concentration. A separation band can be drawn on a plot of particle density and magnetic susceptibility to illustrate the separation of particles that would be achieved. The process fluid is a non–toxic, water–based bio–degradable magnetic fluid, and relatively inexpensive compared to heavy liquids and sodium polytungstates.The Model 100 separator available at the Julius Kruttschnitt Mineral Research Centre is portable and suitable for analysing small batch samples. The separator selectivity is at best ± 0.1 SG units, which may cause a lower grade of products in separations of materials with a small SG differential.The separator has been evaluated for mineral sands applications. Several good applications of Magstream have been identified. Particularly effective separations were quartz/heavy mineral concentrate, kyanite/zircon, monazite/zircon and rutile/zircon (multiple passes required).This paper describes the Magstream process, operation, the mathematical model of separation, and presents the results of the separation case studies in detail.