Concentration of rare metals from printed wiring board of small electronic appliances

A new resources recycling system is proposed, the concept of "Reserve of (waste) to Stock (RtoS)" to create "Artificial Resources Deposit", which involves collection of wasted home electronic appliances from citizens, disassembly of electronic devices, concentration of rare metals in the devices, extraction of rare metals from the concentrate, and also proposing the stock system of the concentrates, for recovering rare metals from the scrap devices in the future. In especial, the target material in the paper was scrap mobile phones, which contain considerable amounts of common, precious and rare metals. The former two kinds of metals have been almost recovered by various pyro-and hydrometallurgical processes. However, most of the rare metals, essential to produce modern electronic devices, are usually discarded every year, which cannot be recovered by conventional nonferrous metals smelting and refining processes. This paper describes the possibility to concentrate the rare metals in electronic devices by application of comminution and physical separation technologies, followed by the application of some novel metallurgical processes to extract them. It is intended to combine (1) comminution to liberate installed devices by a new method and (2) various physical separation techniques to separate electronic parts from each other ("parts separation") and to separate comminuted particles by their composition ("powder separation"). Several kinds of rare metals have been concentrated by the above process which will be expected to be stocked.