Gold From Sea Water

It has been known since 1872 that sea water contains gold dissolved in it. The reason why industry hasn’t yet been able to extract gold from sea water is because of its tiny concentration. If all the gold dissolved in the sea were successfully extracted and cast into a cube, each length of the cube would be a little over nine metres long. When you compare that to the vastness of all the oceans, you can appreciate the dilution involved, and the mammoth task of extracting enough gold to make it worth the effort.

It was suggested by the German chemist Fritz Haber that if a viable method of taking gold from the sea were found, Germany could sell the gold in order to pay its debts after the First World War. As soon as he discovered that he was dealing with such dilute quantities he stopped his research.

There have been several scams involving investors paying for shares in a company claiming to be able to economically extract gold from the sea and inland lakes. By the time it had been discovered that the apparatus used to extract gold didn’t work, the con artist would have already absconded. These fraudulent enterprises may have discouraged meaningful research into what might have been an extremely lucrative industry.

It has been suggested that crown reagents might one day be used to harvest metals from the sea. These chemicals stick to metal ions and keep them in solution. The downside is that they react with water. Research is ongoing into new theoretical compounds which could be stable in water and specifically adhere to gold ions.

Another theoretical method involves channelling sea water across a selectively permeable membrane which has numerous ion channels impregnated in it. The dissolved gold ions and water molecules may pass through the membrane but other ions in solution may not. This increases the concentration of gold on the other side of the membrane. If there are many parallel membranes contained within an isolated unit, it could just be possible for the concentration of gold ions to be high enough to make electroplating from solution, onto a small gold ’seed’ a reality. Growing a bar of gold out of sea water seems like a prospect too tasty to ignore.