Popular Science has an article on the accidental discovery of a new method for extracting gold from ore that uses cornstarch instead of the cyanide salts presently used in production:
Researchers at Northwestern University recently stumbled upon a solution that uses cornstarch instead. It involves some complex chemistry, but it’s cheap, biologically friendly and nasty-ingredient-free.
Led by Sir Fraser Stoddart, a chemistry professor at Northwestern, the team discovered this method by accident when looking for something else. A postdoc named Zhichang Liu was trying to make three-dimensional cubes out of gold and starch, aiming to use them as storage containers for gases and small molecules. But a liquid mixture of dissolved gold-bromide salts and a starch-derived sugar didn’t form cubes, it formed needles. This was strange, so the team decided to try to replicate it and tested different forms of sugars.
The team has already perfected a process to safely reclaim gold from metal scraps and jewelry, and is working on commercially viable methods to extract the precious yellow metal from ore.