Multistage Magnetic Particle Separator II. Classification of Ferromagnetic Particles

Abstract

ABSTRACTA multistage magnetic particle separator was designed and built. The objective of multistage magnetic separation is the collection of particles in liquid suspension according to their net magnetization. The multistage separator was tested in experiments in which suspensions of an iron-carbon composite paniculate in poly(ethylene glycol) were used as feed and in which particles were collected in up to nine fractions according to magnetophoretic mobility. In these experiments particles were aligned in a cylindrical container at a common distance below the top of the container by magnetic levitation using a horizontal bipolar “elevator” electromagnet. After the electromagnet was switched off particles were further levitated by a cylindrical permanent “capture” magnet into a capture chamber directly above and in fluid contact with the container in which the particulate was aligned. After a selected period of time (1–20 min) the capture chamber containing particles that were levitated into it was sheared away from the sample chamber. This process can be repeated up to 15 times using capture chambers in a rotating plate. By changing the time period and capture magnet strength each successive capture results in the collection of particles having decreasing net magnetization based on susceptibility of the particulate material and volume of magnetic material per particle. The test material used in this study was a ferromagnetic particulate consisting of an iron-carbon microcomposite. The separation of a heterogeneous particulate suspension into nine subcategories was demonstrated.