In Japan, disposed automobiles are generally shredded. The valuable metals are recovered from this shredded materials and then the shredder residue is landfilled. However, by the problem of the shortage of reclaimed lands and of the soil pollution caused by the metals in the residue, needs for the material recycling from shredder residue are highlighted. Shredder residue contains nonferrous metals such as copper, lead and zinc. In order to prevent environmental pollution, these nonferrous metals should be recovered from the thermal processed residue of shredder residue.Recovery of nonferrous metals in the incinerated residue of shredder residue has been investigated by Nippon mining & metals group. In Nikko Mikkaichi Recycle Co., Ltd., copper residue and lead slime have been recovered from the incinerated residue in the zinc smelting plant. Copper residue was charged in the converter of copper smelting plant and electrolytic copper was recovered in Saganoseki Smelter & Refinery. Simultaneously, lead slime was treated in the lead smelting plant and crude lead was recovered. The recovery rates of copper, lead and zinc from shredder residue are proximately 90%, 96 96, 74% in the investigation.Mitsubishi Materials Corporation has developed the recovery process of copper and lead by carbonizing shredder residue. The carbonized residue from the carbonization pilot plant of shredder residue was smelted and lead was efficiently recovered in crucible test. At the same time, the copper recovery process was investigated and the process by using conventional copper smelting plant was proposed. These processes are one of the effective methods to recover these metals.
The application of the anomalous X-ray scattering (AXS) technique has been tested for obtaining qualitative and quantitative powder diffraction analysis of a multi-component mixture having a relatively complicated chemical composition and containing two elements of nearly the same atomic number. The system selected for analysis consisted of three chemically different mixtures of Cu2S and CaFe204. The differential intensity pattern obtained from the measurements at two energies, 8.955 keV and 8.680 keV, corresponding to 25 eV and 300 eV below the Cu K absorption edge (8.980 keV), enabled the isolation of the Bragg reflections of Cu2S from the calcium ferrite matrix and provided information for the quantitative determination of the Cu2S component. The results indicate that the AXS technique is promising in reducing the unsolved difficulties associated with the conventional X-ray powder diffraction method. The quantitative analysis of Cu2S in industrial copper smelting slags was also carried out by this new method.
Shredder residue consists of many types of plastics, glasses and heavy metals. When it is landfilled, waste water which contains heavy metals is generated. Thermal processing technology should be developed in order to prevent environmental pollution and reduce its volume. Incinerating technology of shredder residue has been investigated by Nippon Mining & Metal group as a national project since November in 1996. Incineration pilot test plant was constructed by using the zinc smelting equipment which had already shut down in Nikko Mikkaichi Recycle. The incinerating capacity of the plant is 3 t/hr., and 1.5 t/hr. of shredder residue and 1.5 t /hr. of liquid waste are practically incinerated in the pilot test operation. Some operational troubles of the incineration caused by shredder residue have ocurried. Especially, the dust trouble in the off-gas treating plant was serious, However, the pilot plant has been improved, and most of the problems have been already solved.The generation of pollutants from the incineration plant has been kept as extremely low level by the off-gas treating plant and the waste water treating plant. Most of copper in shredder residue is distributed in the bottom ash, and 40% of lead and 30% of zinc are mostly distributed in the fly ash. The bottom ash and the fly ash are treated in the zinc smelting plant in order to recover zinc, lead and copper. Industrial technology of the incineration of shredder residue has been developed.
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