Mining gold has never been considered an environmentally friendly process. In order to get gold out of the earth, extremely toxic cyanides are sprayed on crushed ore to help with the extraction process. While effective, using cyanides regularly leads to environmental contamination, making this a less than ideal method of mining gold. However, up until now, all of the alternatives were either too expensive to consider or they had serious contamination concerns of their own. A recent discovery, though, identified cornstarch as a viable option in making the process of gold extraction much better for the Earth.
The role of cornstarch in gold mining
Cornstarch is an inexpensive, relatively common household product that is typically used to thicken up sauces and soups. Researchers determined that cornstarch could be used to extract gold, even when other metals were present. In addition, there is potential for this new process to get gold out of consumer electronic waste as well. It is important to note, however, that there are several ingredients involved in the process in addition to cornstarch.
An unexpected discovery
The discovery happened as researcher Zhichang Liu attempted to make a cubic structure that would hold small molecules and gases. As he worked, he used two aqueous solutions. One came from alpha-cyclodextrin, which is starch-derived, and the second came from gold salt. Liu combined the two solutions and the result was the formation of small needles rather than the cubes that Liu wanted to create. The researcher, however, was intrigued; his experiment then took a different turn as he decided to look closely at the needles to figure out what they were.
The impact of Liu’s research
Liu went on to do further research, combining a variety of complexes with aqueous solutions. When all was said and done, he figured out that alpha-cyclodextrin was able to isolate gold very effectively. Alpha-cyclodextrin is made up of six glucose units and happens to be a cyclic starch fragment. Researchers were excited by the discovery; removing cyanide from the gold mining process means that extraction can take place in an environmentally friendly way. As a bonus, the new solution is also inexpensive, making it a viable option going forward.
When people hear the words “eco-friendly,” they generally think about green cleaning solutions, carpooling to work or changing their lightbulbs. However, mining gold could soon join the list, a development that comes as a surprise to researchers and miners alike. While using cornstarch to extract gold is not something that anyone could have predicted, the fact that it is affordable and much less harmful to the environment than cyanide has the mining industry buzzing.
Image credit: James St. John, courtesy flickr