Valuable Materials in e-waste
Electronic goods are composed of hundreds of different materials, often of high value. Gold, Platinum, Silver, Copper etc. are valuable materials which recyclers recover from e-waste. A study in 1996 found that more than 50% of the weight of an average desktop computer was in plastics, iron and aluminium. While precious metals as a percentage of the total weight were relatively small, the concentration of such metals, like Gold, was much found to be higher in e-waste than found in naturally occurring mineral ore.
Extracting Gold from E-waste - India
Composition of a Desktop Personal Computer Based on a typical desktop computer, weighing ~27 kg
| Material name | Content (% of total weight) | Weight of material in computer (kg) | Use | Location |
| Plastics | 22.9907 | 6.26 | Insulation | Cable, Housing |
| Lead | 6.2988 | 1.72 | Metal joining | Funnel glass in CRTs, http://www.pwbrc.org/faq10.cfm ">PWB |
| Aluminum | 14.1723 | 3.86 | Structural, Conductivity | Housing, CRT, PWB, connectors |
| Germanium | 0.0016 | < 0.1 | Semiconductor | PWBs |
| Gallium | 0.0013 | < 0.1 | Semiconductor | PWBs |
| Iron | 20.4712 | 5.58 | Structural, Magnetivity | Housing,CRTs, PWBs |
| Tin | 1.0078 | 0.27 | Metal joining | PWBs, CRTs |
| Copper | 6.9287 | 1.91 | Conductivity | CRTs, PWBs, connectors |
| Barium | 0.0315 | < 0.1 | Â | Panel glass in CRTs |
| Nickel | 0.8503 | 0.23 | Structural, Magnetivity | Housing, CRT, PWB |
| Zinc | 2.2046 | 0.6 | Battery, Phosphor emitter | PWB, CRT |
| Tantalum | 0.0157 | < 0.1 | Capacitor | Capacitors/PWB, power supply |
| Indium | 0.0016 | < 0.1 | Transistor, rectifier | PWB |
| Vanadium | 0.0002 | < 0.1 | Red Phosphor emitter | CRT |
| Terbium | 0 | 0 | Green phosphor activator, dopant | CRT, PWB |
| Beryllium | 0.0157 | < 0.1 | Thermal Conductivity | PWB, connectors |
| Gold | 0.0016 | < 0.1 | Connectivity, Conductivity | Connectivity, conductivity/PWB, connectors |
| Europium | 0.0002 | < 0.1 | Phosphor activator | PWB |
| Titanium | 0.0157 | < 0.1 | Pigment, alloying agent | Housing |
| Ruthenium | 0.0016 | < 0.1 | Resistive circuit | PWB |
| Cobalt | 0.0157 | < 0.1 | Structural, Magnetivity | Housing, CRT, PWB |
| Palladium | 0.0003 | < 0.1 | Connectivity, Conductivity | PWB, connectors |
| Manganese | 0.0315 | < 0.1 | Structural, Magnetivity | Housing, CRT, PWB |
| Silver | 0.0189 | < 0.1 | Conductivity | Conductivity/PWB, connectors |
| Antinomy | 0.0094 | < 0.1 | Diodes | Housing, PWB, CRT |
| Bismuth | 0.0063 | < 0.1 | Wetting agent in thick film | PWB |
| Chromium | 0.0063 | < 0.1 | Decorative, Hardner | Housing |
| Cadmium | 0.0094 | < 0.1 | Battery, blue-green Phosphor emitter | Housing, PWB, CRT |
| Selenium | 0.0016 | 0.00044 | Rectifiers | rectifiers/PWB |
| Niobium | 0.0002 | < 0.1 | Welding | Housing |
| Yttrium | 0.0002 | < 0.1 | Red Phosphor emitter | CRT |
| Rhodium | 0 | Â | Thick film conductor | PWB |
| Platinum | 0 | Â | Thick film conductor | PWB |
| Mercury | 0.0022 | < 0.1 | Batteries, switches | Housing, PWB |
| Arsenic | 0.0013 | < 0.1 | Doping agent in transistors | PWB |
| Silica | 24.8803 | 6.8 | Glass, solid state devices | CRT,PWB |
Source: Microelectronics and Computer Technology Corporation (MCC). 1996.
Electronics Industry Environmental Roadmap. Austin, TX: MCC.
