Magnetic Chromatography with a Periodically Intermittent Magnetic Field

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09640721
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 分離・精製・検出法
• Research Institution: Nagoya University
• Principal Investigator: NOMIZU Tsutomu Education Center for International Students, Nagoya University, Professor, 留学生センター, 教授 (50175527)
• Co-Investigator(Kenkyū-buntansha): TANAKA Tomokazu Graduate School of Engineering, Nagoya University, Assistant Professor, 工学部, 助手 (40236609)
• Project Period (FY): 1997 – 1998
• Keywords: magnetic chromatography / periodically intermittent magnetic field / chromatography / magnetic particles / magnetite / hematite / maghemite

Research Abstract

The investigators have developed magnetic chromatography by which magnetic fine particles suspended in liquid stream are separated under a periodically intermittent magnetic field depending on their magnetic properties. Previously, the investigators have succeeded to separate the mixture of magnetite and hematite particles by this approach with an open tubular separation column consisting of PTFE tube placed along the round edge of iron core in a small electromagnet.
In the previous equipment, the maximum magnetic flux density was 170 mT with a 4A of electromagnetic coil current, it is not enough to separate smaller magnetite particles than 0.1μm or particles with weak magnetic properties. In this work, it reaches 1,200 mT with a 30 A of coil current when a large electromagnetic coil, 880 rolls of 2.2 x 3.2 mm square copper wire, is used with a large yoke. After comparing shapes of yoke head, along the round edge of which the separation column is placed, a reverse-cone shape provided the highest performance for chromatographical separation of magnetite particles because of having the longer pathway to maintain the higher magnetic flux density and field gradient.
It was also found that a successive current control of DC supply by personal computer is effective to separate the mixture of magnetite, hematite and maghemite particles, although it was difficult to do by a previous operation only with controlling applied and interval times with a constant current.