Chinese technique recovers over 98% of gold from old phones

Recovering precious metals from electronic waste, known as urban mining, is both profitable and sustainable, but existing methods often rely on highly corrosive or toxic chemicals that harm the environment and human health such as cyanide, according to the South China Morning Post.

To address this, researchers from the Guangzhou Institute of Energy developed a process based on a self-catalytic leaching mechanism, Interesting Engineering reported. In a study published in November 2025 in Angewandte Chemie International Edition magazine, the team reported a gold recovery rate of more than 98.2% from waste central processing units in old mobile phones and printed circuit boards from home appliances, along with a 93.4% recovery rate for palladium.

The team said the process costs about one-third of current market prices for gold recovery, making it the most cost-efficient method reported so far. Processing about 22 pounds (10 kilograms) of discarded circuit boards can yield roughly 1.4 grams of gold at a total cost of around $72, equivalent to about $1,45 per ounce. For comparison, current gold prices are around $4,500 per ounce, according to the American Precious Metals Exchange.

Beyond cost savings, the method uses about 62.5% less energy and cuts reagent costs by more than 93% compared with conventional techniques.

A gold nugget sits on electronics waste. Photo from Instagram

According to the United Nations’ 2024 Global E-waste Monitor, global electronic waste rose 82% between 2010 and 2022 and is projected to increase another 32% by 2030 to about 82 million metric tons. Much of this waste contains valuable metals, including gold, which is widely used in electronics for its conductivity, durability, and resistance to corrosion.

Researchers estimate that printed circuit boards typically contain around 200–900 milligrams of gold per kilogram, according to Popular Science, making discarded phones and computers a potential source of precious metals.