Japan has world's biggest 'urban mines'
The total volume of metal resources, including gold and silver, that are used in electrical appliances and electronics in Japan is the world's largest, surpassing natural metal reserves held by each major mineral-producing country, according to a recent research by a national institute studying materials.
The survey by the National Institute for Materials Science (NIMS) in Tsukuba, Ibaraki Prefecture, was the first to estimate the total amount of metal resources of various nations, including those contained in electrical products and other goods.
Those metals are often described as "urban mines" and have recently been drawing attention for their usefulness.
Amid fears over the depletion of metal resources, efficient recycling of such metals could mean having a "mineral lode" for the country, NIMS said.
A research team headed by Komei Harada, chief of the material laboratory of NIMS, calculated the total amount of metals contained in electrical products and other goods in this country by analyzing data on trading of 20 types of metal imported and exported as materials or finished products.
According to the team, of those metals, there are about 6,800 tons of gold in the country, which accounts for 16 percent of total natural reserves in mines around the world and is worth about 20 trillion yen.
There are an estimated 60,000 tons of silver, or 23 percent of the total reserves in the world, and 1,700 tons of iridium, or 61 percent.
Comparing natural mines in each major mineral-producing country with Japan's "urban mine," this country ranks top in terms of the volume of gold, exceeding the volume in South Africa. Japan also has the world largest silver, lead and iridium resources in the urban mines, according to the team.
Japan has been regarded as a country with few natural resources, but the latest finding shows it is actually rich in rare metals. With the aim of recycling such metals, the research team will calculate the amount of the metals that are not currently efficiently used because they are being discarded.
The team said it also would study methods of retrieving the rare metals from discarded electrical appliances and other products at low cost. "I was surprised that the amount of metal resources in urban areas is so much larger than expected," Harada said.
「都市鉱山」と呼ばれる電気製品の廃棄物などの中に存在する希少金属の国内での蓄積量が、世界有数の天然資源国の埋蔵量に匹敵することを、物質・材料研 究機構が算出し、１１日に発表した。液晶画面の透明電極に使われ世界で獲得競争が激しいインジウムは現有埋蔵量の約６１％（１７００トン）、銀は約２２％ （６万トン）、金は約１６％（６８００トン）に上った。
インジウムや金、銀、鉛の蓄積量は、最大の天然資源埋蔵国より多かった。このほか、ハンダに使われるスズは現有埋蔵量の約１１％、人工骨 などに使われるタンタルが同じく約１０％。世界の年間消費量と比べると、リチウムは７．４倍、白金は５．７倍、インジウムは３．８倍、金は２．７倍に相当 する量だった。
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"Mining town" Japan is one of the largest waste precious metal
January 12, 2008 when 03 min 22
"Mining town" and called waste electrical products such as rare metals present in the country for the amount of accumulation of the world's largest reserves of natural resources comparable to the country, that is calculated to Materials Science , announced on the 11th. LCD screen transparent electrode used indium competitive in the world is acquiring existing reserves of about 61 percent (1,700 tons), silver is about 22 percent (60,000 tons) of gold was about 16% (6,800 tons) above Different.
The amount of accumulation of urban mine, about 20 kinds of metal such as trade statistics and industrial relations table using the materials and components of the product will be included in the import content of their product exports pull demanded. Manufacture and use of products in the overseas release of wastes contained in the minutes also included.
Indium, gold, silver, lead the amount of accumulation is the largest reserves of natural resources from many countries. In addition, tin solder used in about 11 percent of existing reserves, such as artificial bone was also used about 10 percent of tantalum. Compared with the world's annual consumption, lithium is 7.4 times and 5.7 times platinum, indium is 3.8 times the money is equivalent to 2.7 times.
Rare metals, technology and the use of alternative materials to reduce the amount of research and development is underway. Reuse of waste from a powerful way to ensure resources are likely.
The mechanism of the material labs Akira Yuki Harada said, "only a small, rare metals as a waste product is cheaper than the value of being released overseas. Reality check and make effective use of measures need to hurry," he said he said.