How to Recover Gold from Electronic Scrap
You must have heard of using the gold films in various components of latest computerized machines. Though the gold used in these components is merely a thin film coated on the PCB boards. But if you can see and try to collect the thin films from hundreds of such components it can give you a considerable amount of gold with a little effort and technique that will be discussed in this article.
You can retrieve gold from the connector ends which are known as computer fingers. These connectors are covered with a thin gold film which can be removed through an etching process and by removing the copper and nickel layers that will loosen the gold film.
Though, this process involves highly corrosive acids and solutions, so you need to be very careful in carrying it out. Be sure to have gloves, goggles, respirator and acid safe clothes with you before you start the process
To start with the procedure, you will need to have the following things
- Copper chloride solution
- Air bubbler
- A plastic strainer
- A plastic bowl
At first, you will put all the gold plated fingers in the plastic strainer. Fix the air bubblers in a way that the bubbler tube will run below the strainer and into the bowl. Put the strainer containing the gold filmed connectors into the bowl and pour in the HCL so that it covers the gold fingers. Pour in the copper chloride solution as well and add some water to make sure the whole set of gold fingers is covered with the solution.
Turn on the bubbler, cover the bowl and leave it for 24 hours. After 24 hours, you may check in the solution. Separate out the bubbler by removing the tube and you will see the solution now will show the olive green color and a few thin gold foils below the strainer. Set the apparatus back and leave it for next 24 hours. You will see the solution will turn dark green and many of the gold fingers will be clear of the golf film.
Leave the apparatus for 4 more days and after 6 days you will see that all the gold films are now removed through the etching process of copper and nickel layers that make sure the gold is separate out very clearly.
Turn off the bubbler and strain the components carefully. You will have the gold film in the bowl below the solution. Make sure to clean the connectors in water in a clean bucket to get any loose gold film on the components. Preserve the water for filtration in later steps. Let the rest of the materials dry out.
Now take the filtration apparatus, set in the filter paper and pour the dark green solution on it until all copper chloride (green solution) is filtered out which can be used later for next batch.
Pour into the bowl, the water we obtained after washing the components in clean water, with the extracted thin films from the copper chloride solution.
Filter the whole solution through the filter paper to get rid of the water and obtain the thin films.
Now take the filter paper along with the gold foils on it and put in a beaker containing HCL. Heat the beaker to medium heat on a hot plate. The acid in the beaker would be diluted HCL which is half water and half acid.
After the solution gets heated, you need to pour in 3 ml of conc.HNO3 into the beaker to start the process of making Aqua Regia dissolve the gold foils.
You can see the immediate reaction in the beaker and the gold foils will dissolve in the mixture and then the filter paper will take the form of a poop.
You may also insert the foils that were obtained after drying out the connectors to make sure you have as much as the films as possible.
After getting dissolved, you will need to filter the solution to get the clean gold water. To make sure nothing is left in the paper poop, you will have to wash the filtered remains with the help of water by pouring water while it is on the filter paper.
The solution containing the gold is then reduced and dried to extract the gold in the solid form which requires additional steps. This process is all that you need to know about extracting the gold from the computer scrap gold fingers.