Minor rare metals are essential to produce almost any kinds of electric and electronic appliances and the stable supply is of great importance for the manufacturers, because the deposits are quite limited to a few countries. Recycling of such metals is one of the strong methods.The Japanese government settled on recycling regulation in the cabinet and is trying to enforce it this April, in which minor rare metals, especially Ta, Nd, Dy, W, and Co, should be recycled from small domestic appliances (SDAs). However, novel technology is necessary to be developed because most of such metals are presently not recovered due to their low market values. Most of them are discarded into land fill sites and/ or distributed into the slags in non-recoverable state even when collected and fed to non-ferrous metals smelters. An important technology must be the separation of these metals from the SDAs before being charged to the non-ferrous metals smelters in which only heavy and precious metals, Cu, Au, Ag, Pt, etc., are recovered. -This paper introduces a technological approach to recover minor rare metals from scrap SDAs, which was carried out in several national projects managed by the Japan Oil, Gas and Metals National Corporation (JOGMEC). New concentration methods of such minor metals have been developed by combining novel crushing and various physical separation technologies. It was discovered in the project that the devices installed on the PCBs could be detached from the boards in non-distractive form by applying novel comminution. The following "Devices Separation" was considerably a good way to concentrate minor rare metals. In addition, the applicability of all the SDA bearing metals to the "Devices Separation" and conventional "Powder Separation" in the concentration process was demonstrated.
|World of Metallurgy - ERZMETALL
|Published - 2013 5月 1
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