■Both industries are stepping up their efforts to reduce and recycle shredder dust from home appliances and automobiles, which generate approximately 1.2 million tons annually and are mostly disposed of in landfills. The Japan Iron Recycling and Mining Association estimates that the average shredder dust contains 3% copper, 0.3% lead, and 0.5% zinc by weight, which simply means that 36,000 tons of copper, 3,600 tons of lead, and 6,000 tons of zinc are disposed of annually. In addition, the original landfill volume of home appliances (230,000 tons per year) contains 9.4% (58,000 tons) of copper, which can be recycled as a mineral resource to ensure a stable supply of resources. Since most nonferrous metals have a lower melting point than iron, they can be recycled using less energy than smelting from ore, leading to energy savings.
■The "Recycle Mine Bark (RMP) Initiative," launched by the Ministry of International Trade and Industry (MITI) in 1995, is attracting attention. This concept aims to recover and recycle metals from shredder dust and other metal-containing waste by using the ore dressing, smelting, and mine drainage treatment facilities left over from closed mines. In the North Central region, where the RMP concept was approved for the first year, Kamioka Mining (Yoshiki-gun, Gifu Prefecture) and Nikko Mikkaichi Recycle (Kurobe City, Toyama Prefecture) are the main companies involved in the project. Kamioka Mining began recycling automobile batteries in 1994, the year before the certification, and currently processes 4,000 tons of batteries per month to recover and recycle lead, gold, silver, and plastics. In the future, the company plans to study the recovery and volume reduction of valuable metals from waste home appliances, waste OA equipment, and shredder dust. Nikko Mikkaichi Recycle was established in November 1995 based on Nikko Metal's Mikkaichi Smelter & Refinery. The company incinerates shredder dust and extracts distilled zinc from secondary zinc raw materials such as zinc slag using an electric furnace. The smelting process is characterized by its ability to concentrate and recover not only distilled zinc but also copper and lead, and the recovered copper and lead tailings are transported to the Nikko Group's Saganoseki Smelter & Refinery (Saganoseki, Oita Prefecture) for recycling as copper and lead ingots. However, according to the economic evaluation of the shredder dust processing business conducted by Toyama Prefecture in FY98, the total revenue from contracted processing of shredder dust, waste plastic, and waste liquid, and from sales of bullion such as silver was 27,712,000 yen per month. On the other hand, costs for incineration, smelting, and slag treatment totaled 31,747,000 yen, resulting in a loss of 4,035,000 yen. The main reason is that metal recovery costs are more than twice as much as the revenue from bullion sales, and according to our calculations, processing more than twice as much shredder dust as the current level (800 tons/month) would make the business economically viable.
■In June 1998, the Kitashika region of Akita Prefecture, a model region, established the "Recycle Mine Bark Promotion Council" consisting of the prefectural government, mining-related companies, and local governments. The council is now moving forward with a concrete plan to commercialize the recycling of home appliances using the former mine sites of Hanaoka Mining (Odate City, Akita Prefecture) and Kosaka Smelting & Refining (Kosaka Town), both of which are affiliated with Dowa Mining Co. Under the plan, televisions, refrigerators, humidifiers, and air conditioners from three Tohoku prefectures (Akita, Aomori, and Iwate) will be collected, crushed at Hanaoka Mining's ore dressing facility, and copper and lead will be extracted using a flotation separator. The materials are then transported to the Kosaka Smelter and Refinery, where they are recycled into high-purity metals.
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