Posted May 3rd, 2011
How a computer is recycled – literally
We are wrapping up our annual survey this week and we wanted to get a jump on a question that we asked. A part of that survey was in conjunction with our new blog that we started back in November 2008. We asked people if they could have one question answered in regards to electronics recycling, what would it be? The overwhelming question that we received from the survey is: how we do what we do? How do we actually recycle the electronics and what’s the entire process?
By answering this question, we would like to start bringing more transparency to an industry that, lately, has much to hide. We will start with computers and will work our way through other major office electronics in future blogs. This blog post will deal mainly with desktop computers.
So how is a computer recycled? Well, before we start it’s important to understand the major components that make up a computer and what elements are contained in those components.
- The outer case – Usually the case of the computer is made up of low-grade ferrous steel and ABS plastic. ABS stands for Acrylonitrile Butadiene Styrene and it is a very rigid plastic. The plastic also contains Brominated Flame Retardants.
- Motherboard – The motherboard is the main circuit board inside of a computer. The motherboard is made up of a variety of precious metals like gold, silver, copper, and lead based solder.
- Processor – The processor (also known as a “Central Processing Unit” or “CPU”) is a microchip that acts as the computer’s “brain”, executing instructions sequentially as if following a recipe for making a cake. The processor is made of mostly gold and silicon.
- Hard Drive – The hard disk (also known as a “hard drive” or “fixed disk”) is a data storage device containing a rigid magnetic disk. The disk is in a sealed aluminum housing inside of the computer. The hard drive contains mostly aluminum. The hard drive also has a small motherboard which is similar to the main motherboard in the computer.
- Floppy and CD Drive – The CD and floppy drives read data from removable disks. The drives contain steel, copper, and other metals.
- Power supply – The power supply unit supplies a low-voltage current to the motherboard. The power supply is made of mostly steel and copper.
- RAM or Memory – Memory is the part of a computer that stores programs and data during processing. The memory modules are made with mostly gold and silicon.
- Expansion Card – An expansion card is a circuit board that can be plugged into a computer’s motherboard to provide additional functions. Expansion cards are almost identical in metal content to motherboards.
- CMOS Battery – Most computers contain a small button-like battery. This battery is an alkaline-type battery and is one of the most toxic items in the computer.
So now that you know what’s in a computer, let’s talk about how the different metals and plastics are recovered and refined. When it comes to computers, we are able to recover and recycle 100% of the material. Since reusing items greatly reduces the negative impacts on the environment, we try to remove as many reusable parts as economically possible. When all reusable parts have been removed from the computer, it is ready for shredding and separation. The first step in processing the computers for shredding is to remove the CMOS battery. If it is left in the computer, this battery presents problems to the size reduction shredders that are used to separate the material. Once the CMOS battery is removed, it’s recycled using an approved battery recycler located in the United States. During the process of removing the CMOS, the cover of the computer is removed. The cover is usually made up of light iron (ferrous). All low light iron that we generate is processed locally at several metal-processing facilities. The iron is passed through size reduction shredders, loaded on rail cars or barges, and then sent to steel mills.
At this point, the computer is basically intact. The only thing that has been removed is the cover panel, CMOS battery, and any possible reusable parts. The computer is now ready for material separation and recovery.
This three-step process maximizes material recovery:
The first step is the preparation phase. This phase of the process is where the computer is downsized by very large industrial shredders. These shredders grind down the entire computer into small, manageable pieces. The shredded material runs over a machine called an eddy current separator which contains a magnet on a roller. As the material moves over the roller, the steel (or ferrous as they call it in the recycling world), the precious metals (which are in the motherboard), hard drive, wire, and processor are then separated by the eddy current separator. That separated steel is then freighted to local steel mills. The precious metal material then moves on to the second phase of the process.
The delamination phase begins to process the shredded material even further by using a fractionator. This machine spins the shredded material against a series of knives effectively breaking the physical bonds of the material, liberating it for final recovery.
The final step is the separation and refinement. This is where the delaminated material is separated into three different recoverable fractions:
- Red metals: Copper and precious metals
- White metals: Aluminum alloys
- Plastics: Mixed Plastics, free of metal contamination
Finally, the different fractions are processed by refineries that specialize in metals and plastics. Once the material leaves the refinery, it is in the form of raw materials and is then ready to be reused.