TSUKUBA, Ibaraki Pref. – Japan has the biggest “urban mine” in the world because gold, silver, indium and other recyclable rare metals are accumulating in its home appliances, a local research institute said Saturday.
Japan owns about 6,800 tons of gold (16 percent of the world’s known deposits) and about 60,000 tons of silver, accounting for 22 percent of global deposits, according to the research by the National Institute for Materials Science.
Furthermore, Japan’s stockpile of indium, used to make liquid crystals, constitutes around 61 percent of global deposits, it said.
“While many products with these materials are usually transferred overseas as post-consumer waste stuffs, we would like to study how to use these potential resources,” an institute official said.
The institute researched about 20 rare metals used in home appliances, based on government trade statistics.
It calculated Japan’s stockpiles of the rare metals by subtracting the amount exported — including those used for exported parts and finished products — from those imported, including those used in imported goods.
It also includes rare metals in home appliances being manufactured and in use, as well as those in discarded products, the institute said.