Printed circuit boards are all over. Think of the electronic products that you have come across. They all have a printed circuit board as the fundamental piece in their makeup. Unfortunately, a relatively high number of electronic scraps also imply that many PCBs go to waste. Still, the waste circuit boards can help assemble electrical components. Thus, it's essential to have a recycling process for these valuable materials. In that regard, our article will delve into the essence of recycling PCBs. Furthermore, it'll expound on the PCB recycling process.
Why Recycle PCB?
Electronic Waste
People casually disposed of electronic waste and other hazardous materials in the past. However, the electronic industry has grown bigger, implying more destruction than ever. Thus, the recovery of materials is more important than ever.
We can use it as a raw material for other electronics rather than the waste circuit board finding its way in pits.
How to Recycle Circuit Boards?
Green Printed PCB without components.
It is possible to recycle PCB boards, but you will not get everything back. The primary materials in PCB are copper and FR-4. You can use this copper as an electrical conductor. However, you can only obtain pure copper as the fiberglass will degrade in the recycling process. Still, fiberglass is essential in several low-tech applications.
Here are the ways to recycle PCB:
Thermal Recovering
As the name suggests, the technique involves subjecting the PCB to high temperatures. Primarily, it's handy in the recovery of metals as the FR-4 cannot survive high temperatures. Also, it's easy to implement, but it releases hazardous fumes of lead and dioxin.
Chemical Recovering
Firstly, you need to place the PCB in a bed of acid. The acid solution will digest the FR-4, making it impossible to recover. Like the technique mentioned above, you can only contain metals from this recovery process.
Also, the process will release wastewater which you can reuse after treatment.
Computer parts ready for recycling.
Physical Recovering
It involves the physical separation of metals from nonmetals. Primarily, this is via first smashing and shredding the PCB. Recycling wasted printed materials using this process is safe as it doesn't contribute to environmental pollution.
However, it has several hazards for the operators. First, the machine involved is extremely noisy. Secondly, it emits dust particles laden with heavy metals and other intoxicants. Lastly, the high temperature causes the PCB to produce an irritant odor.
Circuit Board Recycling Process
Printed circuit board with components
The primary process involves cutting and sorting the PCB components via the following steps.
- First, you need to remove the components attached to the green boards via drilling.
- Next, cut the PCB board into tiny pieces.
- Also, you need to separate ferromagnetic materials from non-ferrous metals. Thus, you'll require magnetic separators to isolate the non-magnetic waste.
- Lastly, you need to sort out other materials such as ceramics and fiberglass.
After cutting and sorting, companies in the recycling industry use three main procedures.
Electronic Waste
Pyrometallurgy
Pyrometallurgical processes involve heating the PCB to approximately 1400 to 1600 degrees. Subsequently, metals such as lead, tin, and oxides will change to a liquid slurry. Additionally, the heating will change organic materials to hydrogen and carbon monoxide.
Hydrometallurgy
First, you need to dissolve the PCB in a solution of aqueous leaching agents. Next, you need to add a precipitation agent to convert the slurry from liquid to solid waste. Lastly, add the materials to an ion exchange system to remove the metal ions.
Electrochemical Process
Primarily, this procedure involves the separation of precious metals via electrolysis from the waste stream.
What You Can Recycle from Printed Circuit Boards
Copper is the main product recovered from PCBs.
Essentially, recycling aims to acquire as many metal scraps as possible. The precious primary materials that you'll recover are copper and tin. You'll obtain copper from:
- Treatment sludge
- Edge trim
- Etching solution
- Rack stripping
- Solder stripping
Furthermore, in the extraction of copper, you can also obtain copper hydroxide, specifically in the hole process. Lastly, you can generate tin during the hot air leveling procedure.
How to Make PCBs More Recyclable?
A PCB board without components
There is an ever-increasing number of PCBs in the electronics industry. Thus, we need to recycle more waste electrical materials. However, at the moment, there's little that we can do to improve PCB recyclability.
Earlier, there was a notion that using SMD components in place of THT could improve PCB recyclability. Nonetheless, this has proven to be ineffective.
Summary
Environmental protection is a critical concern in the present world. Thus, all stakeholders in the PCB industry need to join hands to ensure that there is little electronic waste. It will be handy in limiting the energy consumption in the PCB production process.
At OurPCB, we are leading advocates in PCB recycling. Thus, if you have any queries on this process, talk to us at any time.