A new gold recovery method based on corn starch instead of cyanide could help reduce the amount of toxins introduced into the environment during gold mining.
The process was discovered by accident when Northwestern University postdoctoral fellow Zhichang Liu mixed together two solutions at room temperature: one containing the corn starch-derived alpha cyclodextrin and the other containing a dissolved gold salt. Liu had been hoping to create cubes to store gases and small molecules, but instead the mixture produced bundles of gold needles made up of tiny gold wires that could be harvested from the liquid.
Not only is the corn starch-based gold extraction process less expensive than conventional methods, it is also less toxic—producing the relatively benign alkali metal salt as a by-product.
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