What is e-waste?
- Electronic waste or e-waste refers to electronic products that have been discarded or have reached the end of their life.
- Electronic scrap such as mobiles, computers, laptops, etc. contain toxic elements such as beryllium, cadmium, lead, etc. which can pollute the environment.
- The world produces 50 million tonnes of e-waste every year, out of which 80% ends up in land fill, polluting the soil.
The value of e-waste
It is estimated that 100,000 mobile phones contain 2.4 kg of gold, 25 kg of silver, and 900 kg of copper and other metals.
Issues in extracting gold from e-waste
- Gold is almost inert and does not dissolve easily in chemical solutions making extraction from e-waste very difficult.
- The common techniques used for extraction of gold require huge quantities of sodium cyanide which is environmentally toxic.
- The earlier processes required 5000 liters of aqua regia (a mixture of nitric acid and hydrochloric acid) which cannot be reused, thus increasing the cost.
The new process
- The new process uses a solution of acetic acid mixed with oxidants and other acids to dissolve gold at a much faster rate.
- The solution does not have any negative environmental issues associated with it.
- It is economically cheap as it costs 50 cents a litre and can extract 1 kg of gold using 100 litres of the solution.
Advantages of new process
"We've found a simple, cheap and environmentally benign solution that extracts gold in seconds, and can be recycled and reused," - Professor Stephen Foley, University of Saskatchewan in Canada.
Now, a technique to extract gold from e-waste
- Scientists from University of Saskatchewan in Canada have discovered a novel technique to extract gold from e-waste.
- Gold extraction from e-waste until now has been environmentally damaging because of the involvement of sodium cyanide.
- The new technique is not only economically feasible but also environmentally benign.
- The team of Professor Stephen Foley will now aim to scale up the process for large scale applications.