New development of compact magnetic separator for on-site material screening in various geological survey

Abstract

Magnetic separation has been recognized as a valuable technique for extracting or separating target materials from mixed heterogeneous particles. In conventional geological research, it has been used to separate ferro- and ferri-magnetic minerals such as Fe–Ni metal, magnetite and ilmenite. Recently, a mixture of diamagnetic and weak paramagnetic particles has been successfully separated into groups of different materials using a compact magnetic circuit; however, the resolution was not sufficiently high to analyze various heterogeneous particles studied in geological research. Here, we show that the resolution has remarkably improved by developing new magnetic separator. Accordingly, the separation efficiency of particles due to magnetic translation increased by a factor of ~ 2.5, and two different materials were definitely resolved when their variance of the magnetic susceptibility exceeded ~ 2 × 10−7 emu/g; previously, limit of the resolution was above 7 × 10–7 emu/g. We also established the orbit simulation program in magnetic and gravitational field, which accurately predicted the actual trajectory due to magnetic translation. The improved separation resolution of the new separator has significantly increased the range of solid materials that can be magnetically separated, and the range of applications has been considerably expanded to include the matrix of primitive meteorites, surface soils of solid planets and satellites, volcanic ash and sedimentary rocks. The newly developed device is compact and requires little electric power, allowing on-site material screening in various geological research.