Production of “Urban Ore” from Used Electronic Equipment without Human Intervention

Development of a Simple Recycling Technique Applying Small-Scale Distributed Treatment Based on Paradigm Shift

2008.11.26

National Institute for Materials Science

Dr. Kohmei Halada, Managing Director of the Innovative Materials Engineering Laboratory and Managing Director of the Strategic Use of Elements Interdisciplinary Cluster at the National Institute for Materials Science, developed a simple technique which is applicable to small-scale distributed treatment for promoting the recovery of scarce elements from the used products called “urban concentrates.”

Abstract

  1. Dr. Kohmei Halada, Managing Director of the Innovative Materials Engineering Laboratory and Managing Director of the Strategic Use of Elements Interdisciplinary Cluster at the National Institute for Materials Science (President: Prof. Teruo Kishi), developed a simple technique which is applicable to small-scale distributed treatment for promoting the recovery of scarce elements from the used products called “urban concentrates.”
  2. This method utilizes the crushing capacity and crushing characteristics of the ball mill. After being roughly crushed to approximately several cm in length, electric devices are charged and treated in ball mill without sorting, enabling selective separation/powdering of the components and plating on boards. This results in the formation of a powder less than 1mm in size, in which scarce metal components are concentrated, and thus makes it possible to obtain “urban ore” in a powdered ore form which is easily treated by flotation, melting, and other downstream processes. Because this process leaves plastics, aluminum, and copper-containing boards respectively in sheet form, the remaining non-powdered components are also easily sorted in the following process.
  3. In almost all cases, the recycling processes used in Japan up to the present comprised disassembly and sorting, followed by crushing and other processes. Great effort had been devoted to developing an effective method of disassembly and sorting without manual intervention. In contrast, rather than applying manual work or technologies to forcibly disassemble groups of products when inadequate effort has been given to “design for disassembly”, which is essentially a responsibility of the product manufacturer, this technology is based on a paradigm shift in which the electric devices are regarded practically as mixed materials and charged collectively to the process, and is then separated taking advantage of the physical properties of the substances themselves and the connecting parts.
  4. The ball mill has been widely used as a powder manufacturing technology to date. However, by overturning the conventional common sense and charging large objects of a size exceeding the crushing limit into ball mill, conversely, it is possible to selectively separate parts such as junctions, ceramics, plating, and the like, while leaving structural parts such as plastics and aluminum which are difficult to crush. Furthermore, these separated materials are pulverized by the essential effect of the ball mill.
  5. In addition to the fact that this method is possible using simple equipment, namely, the ball mill, there are few environmental and siting restrictions, as it basically does not require heat or water. From this viewpoint, it is suited to small-scale distributed type production of “urban ores” containing concentrated scarce metals. For more effective practical application, joint study of the ball and rotation conditions, etc. corresponding to the treatment scale is underway with private companies.
  6. An exclusive NIMS patent application for “Crushed material obtained from electronic equipment” and a joint patent application with Re-Tem Corporation for “Electronic equipment crushing method” have been filed in connection with these results. On December 12, this achievement will be announced at the “Urban Concentrates Workshop II,” which is to be held under the sponsorship of the Ecomaterials Forum, with joint sponsorship by the NIMS Strategic Use of Elements Interdisciplinary Cluster.