Clarifying liberation mechanism of electrical disintegration by electromagnetic field analysis

Rintaro Hayashi, Shuji Owada

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

The enrichment of useful components from ores and/or wastes has become important with increasing recent worldwide resources demand and the amount of wastes generated from the urban mines, in order to establish real "sound resource-cycle society" including the activity of resource exploitation. The first stage of the treatment in the process must be comminution and it is important to make good liberation among compositional phases in the targeted resources. Electrical disintegration (ED) is well known to make a selective breakage at phase boundary. However, the detailed mechanism of the phenomena is not clarified yet, in especial, on the influence of electrical properties of compositional materials on the liberation. This paper made a comparison between the liberation degrees of ED products and the results of electromagnetic field analysis using finite element method (FEM). In the experiments, we used several synthetic cement paste based samples in which mineral particles were dispersed to apply the ED, and in the electromagnetic field analysis, we calculated the charge density accumulated and the Maxwell stress at phase boundary. It was found, for highly insulating mineral samples, that higher breakdown voltage was necessary because electric charge was not easily accumulated at phase boundary but that higher liberation degree was obtained after the breakdown (ED). It was also found the tendency that higher liberation was observed for the samples which had higher maximum Maxwell stress calculated by the electromagnetic field analysis. From the results, the electrical charge and Maxwell stress induced at phase boundary could be driving forces of selective breakage. In addition, we also applied the ED to the printed circuit boards (PCBs) in order to concentrate miner rare metals, which were essential for producing electronic devices. It could be demonstrated that the devices installed on the PCB were easily detached from the board and that most of metal elements in the devices was exposed and liberated from the insulating plastic covers, which were broken in the ED, then, it is considered that the subsequent solid phase separation could be effective for concentrating such metal elements.

Original languageEnglish
Title of host publication26th International Mineral Processing Congress, IMPC 2012
Subtitle of host publicationInnovative Processing for Sustainable Growth - Conference Proceedings
Pages1951-1961
Number of pages11
Publication statusPublished - 2012 Dec 1
Event26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - New Delhi, India
Duration: 2012 Sep 242012 Sep 28

Publication series

Name26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings

Conference

Conference26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth
CountryIndia
CityNew Delhi
Period12/9/2412/9/28

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Keywords

  • Electromagnetic field analysis
  • Liberation
  • Miner rare metal
  • Printed circuit board

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geotechnical Engineering and Engineering Geology

Cite this

Hayashi, R., & Owada, S. (2012). Clarifying liberation mechanism of electrical disintegration by electromagnetic field analysis. In 26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings (pp. 1951-1961). (26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings).