Isolating Gold Without Cyanide
For millennia humanity has been fascinated with gold, first making jewelry from it and more recently advanced pieces of technology. These applications combined with its scarcity makes gold one of the more sought after elements in the world, so any economical means of collecting it is used. Now researchers at Northwestern University have discovered a new means to isolate gold dissolved in a solution using a cornstarch derivative.
While many people may imagine gold mining as something achievable with a pickaxe, it actually involves a great deal of chemistry as many gold sources are crude, and have it bonded with other, undesired elements. Currents methods of isolating the gold from these other elements require cyanide, which results in hazard waste products. The Northwestern researchers however stumbled upon a new way to grab the gold out of solutions while trying to create cubic nanostructures for storing small molecules and gases. Instead of cubes, needles formed and once these were examined, the researchers found the gold atoms within them were isolated, along with other metals.
After some experimentation, the researchers found it was alpha-cyclodextrin, a starch fragment that was most capable at isolating the gold atoms. In fact it is more efficient at isolating gold than the current cyanide based methods, so we may soon see industries adopting it to harvest gold from natural sources, and potentially scrap alloys.
Source: Northwestern University