24/04/2019· Scientists believe all the gold on Earth formed in supernovae and neutron star collisions that occurred before the solar system formed. In these events, gold formed during the r process. Gold sank to the Earth's core during the planet's formation. It's only accessible today because of
The Miller process is rapid and simple, but it produces gold of only about 99.5 percent purity. The Wohlwill process increases purity to about 99.99 percent by electrolysis. In this process, a casting of impure gold is lowered into an electrolyte solution of hydrochloric acid and gold chloride.
Wohlwill process The electrolytic method of gold refining was first developed by Dr. Emil Wohlwill of Norddeutsche Affinerie in Hamburg in 1874. Dr. Wohlwill's process is based on the solubility of gold, but the insolubility of silver, in an electrolyte solution of gold chloride in hydrochloric acid. The impure gold is cast into anodes of about 100 ounces each, which are suspended in porcelain cells,