Electrorefining is a process that uses the principals of electrolysis to recover gold from an alloy typically found in jewelry. Electrolytic gold recovery begins with a bath of hydrochloric acid, which forms the electrolyte. The cathode is usually a thin sheet of 24K gold, but it needs to be better than 99.5% pure. The gold alloy (source material) comprises the anode. This method is called the Wohlwill process.
While a high electric current passes through the electrolyte, between the anode and cathode; the acid bath dissolves the anode material and, through ion transfer, a high purity of gold is transferred onto the cathode. Gold purity is typically 99.999%. Once the anode has been dissolved, the gold cathode can be removed, rinsed and melted into ingots. Unfortunately, the entire process can take a couple of days.
For economical refining; often a different refining process, known as the Miller Chlorination Process, is used to separate gold to a purity of about 99.5%. The impure portions of this alloy will contain a significant amount of silver. The Miller refined gold can then be electrorefined to improve purity to 99.999%.