A Study on the Development of an Open-Gradient Magnetic Separator Under Dry Condition

Abstract

This is an attempt to explore feasibility to develop an open gradient magnetic separator for mixed powder under dry condition. The magnetic separator proposed here is intended to separate the ferromagnetic particles from mixed powder, being based on the consideration that the separation efficiency depends upon changing systematically the particle sizes and its surface properties such as hydrophobicity and cohesive force. As a result, it is found that the separation efficiency became lower as the particle size of the mixed particles became smaller. This is supposed to be caused by the cohesive force between the particles of ferrite and alumina which are easily affected by the magnetic drag force and the gravity difference. But the result is encouraging because the separation efficiency will be enhanced if the magnetic gradient is increased and if air flow in the separator is optimized in the appropriate system of the open-gradient magnetic separator proposed in this paper.

Removing metal debris from thermosetting EMC powders by Nd-Fe-B permanent magnets

“…Hence, the configuration of the parallel arrangement of magnets is selected in this study. As the efficiency of separation of metal debris from EMC powders depends on the size, density and speed of the metal debris, and magnetic strength [8], a proper selection of the magnets and their arrangement are essential. Thus, the field strength of the proposed parallel configuration is examined first as follows.…”

“…Even though the removal of metal debris in the EMC powders is essential in the electronic packaging industry, the related issue was rarely reported in the literature. This situation is very unique comparing to other industries facing similar issues, such as those in making foods, drugs, general powders [4][5][6][7][8], and metal machining [9,10]. For the food, drug, and general powder industries, the causes of metal debris are similar to those of EMCs.…”

“…Hence, for these industries, various methods have been applied to remove metal debris. These methods of removal are generally based on permanent magnets as the debris are usually ferromagnetic materials [4][5][6][7][8][9][10]. However, comparing to these industries, the uniqueness of lacking in the literature of metal debris removal in the EMC industry deserves special attention.…”

Application of superconductivity for magnetic force control in medical and industrial fields

“…For this reason, the blockades in a separator are often caused and then the separation efficiency decreases markedly. When the diameter of the particle becomes smaller, the magnetic force to the object becomes smaller and the cohesive force increases because specific surface of particle becomes larger [4]. These make the magnetic separation more difficult.…”

Research and Development of Superconducting Magnetic Separation System for Powdered Products

“…This makes the magnetic separation more difficult. [1] The permanent magnet and electromagnet have been used for the separation of the powders. The neodymium magnet makes it possible to make the higher magnetic field of 1 T. Though the neodymium magnet makes it possible to make Manuscript the higher magnetic field of 1 T, the magnet has not enough performance to separate particles because the strong magnetic field can be produced only in the vicinity of the magnet.…”