Magnetic separation using superconducting magnets

Since the 1970s, magnetic separation has been increasingly used for purification of liquids, such as heavy-metal ion removal from laboratory waste water, purification of kaolin clay in the paper-coating industry, waste water recycling in the steel industry, and recycling of glass grinding sludge in cathode-ray tube polishing factories. In the 1980s, large superconducting magnets were adopted for the field coils of high-gradient magnetic separation systems used for kaolin clay purification. After the development of liquid-helium-free superconducting magnets in the 1990s, new national research projects were initiated in Japan to expand the application of superconducting magnetic separation to other areas. This paper discusses some of the fundamental characteristics of magnetic separation, the progress of super-conductorization (use of superconducting magnets as field coils in magnetic separation systems) and recent R&D activities at the National Research Institute for Metals in Japan. (C) 2001 Elsevier Science B.V. All rights reserved.