Gold, the precious metal that built and destroyed empires, was the focus of millions of investors for years. Two years ago, gold prices peaked at around $2,000 per ounce. This ongoing interest in gold not only motivated ancient kings to start wars of conquest but also inspired a team of scientists to search for innovative methods of extracting gold.
In late March of 2015, a team of researchers found that human waste contains minute traces of gold and other precious metals. This waste is carried to wastewater facilities along with other metal-containing products like detergents. By taking waste samples from different communities, scientists have determined that the gold level in the sewage is the same as that of a minimal mineral deposit — an amount that is commercially viable to extract from rocks.
This is not the most recent advance in gold extraction, however. Recently, a research team discovered an efficient method of stripping gold from electronic wastes. Modern electronics contain very small parts that are powered by low currents. As a result, a reliable, corrosion-resistant metal is necessary for the devices to work. Therefore, most electronics contain trace amounts of gold that are bound to their internal components.
However, extracting gold from electronics is difficult, and the amount of recovered gold from a single device is very low. Gold is a very non-reactive metal, which forces companies to use chemicals such as sodium cyanide to dissolve and extract gold. However, sodium cyanide is both environmentally damaging and expensive, making it unsuitable for stripping small amountsof gold from electronics.
To avoid using sodium cyanide, the research team, led by Stephen Foley, an associate professor at the University of Saskatchewan, developed a method that relies on a combination of acids and oxidants. This solution consists of acetic acid mixed with an oxidant which, in the presence of another acid, dissolves gold at a record rate.
In their experiments, gold from electronic circuit boards were dissolved in around 10 seconds. In a large scale study, 100 liters of the solution was capable of dissolving one kilogram of gold. Additionally, the fluid is cheap and more environmentally-friendly than sodium cyanide; a liter of this solution costs 50 cents and can be reused in subsequent extractions.
This novel solvent resembles a more commonly known liquid called aqua regia. Known for being very corrosive, aqua regia consists of a mixture of nitric acid and hydrochloric acid that, in the correct ratio, can dissolve nonreactive elements such as gold and platinum.
Although it can be used to extract gold, there are several disadvantages to using aqua regia. First, the components of the solution react with one another, speeding up the decomposition of the liquid and reducing its effectiveness. Furthermore, only one kilogram of gold can be extracted with 5,000 liters of aqua regia, none of which can be recycled.
As a result, the solution developed by Foley is currently considered one of the best options for commercial extraction of gold from electronic wastes.
FAQs
Researchers have recovered gold from electronic waste. Their highly sustainable new method is based on a protein fibril sponge, which the scientists derive from whey, a food industry byproduct. ETH Zurich researchers have recovered the precious metal from electronic waste.
Is it worth it to extract gold from electronics? ›
While extracting gold from electronics is not without its challenges, it can be worth it for individuals looking to recover valuable metals and reduce e-waste. However, following safety precautions and using personal protective equipment when handling hazardous chemicals is essential.
Can you make money getting gold from electronics? ›
Scientists have developed a highly effective method to recover gold from electronic waste, an advance they say could yield $50 worth of gold for every dollar spent.
What is the extract process of gold? ›
The principal technology is the cyanide process, in which gold is leached from the ore by treatment with a solution of cyanide. The first step is comminution (grinding) to increase surface area and expose the gold to the extracting solution. The extraction is conducted by dump leaching or heap leaching processes.
What electronics have the most gold content? ›
The components with the highest content of precious metal include:
- CPUs.
- Memory.
- Circuit connectors.
- Motherboards.
- Cables and wires.
- Hard drives.
- Cell phones.
But how much gold is found in a computer? On average, a desktop computer contains about 0.2 grams or 0.007 ounces of gold. While this may seem like a minuscule amount, the gold content can significantly accumulate if you are considering a large-scale recycling operation.
Do old TVs have gold in them? ›
Televisions are made of several different materials. Some of the most valuable components of an older CRT monitor are metals. CRT TVs usually contain parts made of copper, gold, iron, steel, and many more, all of which can be refined for the manufacturing of new products.
How pure is electronic gold? ›
By: Bob Dixon, Product Line Director, Electronic Materials
Materion is one of few companies able to consistently refine gold to the 99.999% purity level. That ultra clean purity level is required by some of the most advanced high technology companies.
How much gold is in the average electronic? ›
It's also not including the cost to remove it. Other sources estimate that the average computer contains 1/5th gram of gold, which is worth about $12. Laptops, on the other hand contain around 1/10th gram or $6 in gold. The actual value of the e-waste will vary depending on its type.
How much gold is in a smart TV? ›
Not very much. In fact, almost none. Gold, at $1900 per troy ounce (31.3 grms), is too costly to use very much of it in any electronic device. The cheap TV sets will use tin plating where gold might be used in the higher end TVs.
Circuit boards are the biggest users of gold: more specifically, motherboards. This is because gold can be found on their surfaces and connectors. Other precious metals like copper and aluminum can be found in electronics, as well. That said, these materials aren't as highly valued as gold.
What machine is used to extract gold? ›
Several types of machinery are used in mining to extract precious metals, such as gold, silver, and platinum. Some of the biggest machines used in the extraction of these metals include excavators, draglines, shovels, giant trucks, crushers, and grinding mills.
How long does it take for gold to form naturally? ›
Gold formation takes millions to billions of years. Through geological processes like hydrothermal and magmatic activity, gold slowly accumulates in deposits over vast timescales.
What chemical is used to extract gold? ›
Leaching chemicals include: Sodium Cyanide: It is extensively used in cyanide leaching for the extraction of gold. Activated Carbon: Activated Carbon helps in the adsorption of gold-cyanide solution. Caustic Soda: It is responsible for the elution stripping of adsorbed gold on activated carbon.
What chemicals are used to extract gold? ›
Leaching chemicals include:
- Sodium Cyanide: It is extensively used in cyanide leaching for the extraction of gold.
- Activated Carbon: Activated Carbon helps in the adsorption of gold-cyanide solution.
- Caustic Soda: It is responsible for the elution stripping of adsorbed gold on activated carbon.
Removing Gold Using Fire
Use steel tongs to turn over the burning circuit boards. Get a metal bin or tray, and put the circuit boards into it. Break the boards into smaller pieces so they burn faster. Light the boards on fire.
