Scientists from Northwestern University have discovered an environmentally kinder way to mine gold, which involves using simple cornstarch instead of cyanide to isolate gold from raw materials in a selective manner.
The scientists say that this "green" technique extracts gold from crude sources and leaves behind other metals that are frequently discovered mixed together with the crude gold. The technique can also assist with the removal of gold from consumer electronic waste.
Most gold mining companies today use gold extraction techniques involving the use of cyanide, which is very bad for the environment.
Sir Fraser Stoddart, the Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences, says that researchers have switched "nasty reagents with a cheap, biologically friendly material derived from starch."
Interestingly, the starch method was discovered by accident, using simple test tube chemistry. The scientists mixed together a test tube of the starch-derived alpha-cyclodextrin and one of a dissolved gold salt. They had been attempting to produce a three-dimensional cubic structure that could be used to keep gases and tiny molecules. Instead, they got needles, which formed quickly upon mixing the two solutions at room temperatures.