Rocks, Minerals and Your Computer
Many minerals have unique properties. Fortunately, we have discovered ways to put them to use in improving our standard of living. Without rocks and minerals, many of the gadgets and gizmos you depend on every day - including the computer or cell phone you are using to visit our website - could not exist.
About 15% of electronic devises and equipment are recycled in the United States (according to Wikipedia). Recycling is considered an important environmental tool. Obsolete computers and other old electronics can be valuable resources for secondary raw materials. More than 35 minerals and metals (such as tin, silicon, iron, aluminum and a variety of plastics) are used in the construction of a variety of electronics, but only precious metals such as gold, silver, copper and palladium are currently valuable enough to be considered for recycling. (For those not familiar with palladium, it is used to make good electrical contacts, to make some surgical instruments, and used for parts in watches and other jewelry.)
The quantities and type of materials used in computer and other electronic products vary depending on the manufacturer and the purpose of the device. Gold and other precious metals in an obsolete compute/electronics have to be collected, concentrated and refined in order to acquire a higher value.
According to the EPA, for every million cell phones we recycle, 35 thousand pounds of copper, 772 pounds of silver, 75 pounds of gold, and 33 pounds of palladium can be recovered; reference EPA.
Circuit boards and batteries contain most of the heavy metals and have the highest percentages of precious metals. It has been reported (Veldhuizen and Sippel, 1994) that one metric ton of circuit boards can contain between 80 and 1,500 g of gold and between 160 and 210 kg of copper.
So historically, recovering precious metals from obsolete computers and old electronics has been good for the recycling industry (USGS Fact Sheet, 2001). However, more recently in an effort to reduce production costs of electronics, companies have been reducing the amount of the precious metals in the manufacturing of electronics (Porter, 1998).
The following graphic illustration shows how much of each of the three precious metals (in Troy ounces) was recovered from (1) a 486 PC, (2) a 586 microprocessor, (3) a cellular telephone and (4) an outdated external modem. It also shows the dollar value recovered from each based on the value of each of the metals at the time the operation took place. But be aware that prices for precious metals change almost daily.
As a class exercise, recalculate the value of the gold, silver and palladium based on current prices. You can find the latest updated precious metals prices by visiting the website of precious metals dealer Monex. The number you will want is listed under the "Precious Metal Spot Prices". Remember: Although we still use the Avoirdupois system in the US and most other countries use the Metric system, the weight of a precious metal is nearly always given in Troy ounces.