The big sacks lined up in one corner of the facility are full of cell phones, computer motherboards, IC chips and other items taken from discarded consumer electronic goods. At first glance they look like they are ready for the dump, but no—they are actually a potential gold mine, yielding several hundred grams of almost 100% pure gold per ton.

Most gold is kept as bars or jewelry, but things are changing. Some time ago, electric and electronic industries began using gold to plate certain components. Before long, they were using gold on IC chip electrode surfaces and connecting the electrodes with gold wires. A more recent innovation is golden vapor-deposited film on recording media surfaces. So today, industries use a surprising amount of gold.

How much gold is stored away in such forms? Dr. Harada Komei of the National Institute for Materials Science (NIMS) says, “We’re assuming 6,800 tons, in Japan alone.” That would represent 16% of the mineable gold deposits worldwide, and more than the deposits in South Africa, the biggest gold-producing country on the planet.

If the world keeps using rare and precious metals, or iron or copper for that matter, at the same pace as before, they will all be used up one day, just as oil will be. This is why attention is turning to “urban mining,” which means collecting valuable components from no-longer-used products all over Japan, and recycling their metals, especially the rare and precious ones.

Today’s cell phones would not function well without gold parts.
Above: Crystal oscillator covers. They come in different shapes and sizes.
Left: Wire used to connect IC chip electrodes.

“Urban mining” is being pioneered by metal refining companies. They have started collecting and recycling components that contain gold, silver, and rare and precious metals like platinum and palladium. The facility mentioned at the beginning of this article is retrieving gold that is 99.99% pure, using chemical and electrolytic processes on the “ore.” They get more than 500 grams of gold for every ton of components.

But it certainly is not easy to start up an “urban mine.” For one thing, although tens of millions of cell phones are taken out of service every year in Japan, only about one-third are collected for recycling. Dr. Harada and his fellow researchers studying resources and material recycling say the recycling industry really needs to find ways to collect unwanted electronic goods from homes, companies and factories, so that their circuit boards, IC chips and other valuable components can be recovered.