Potential-controlled gold purification method

The invention discloses a potential-controlled gold purification method. The method comprises the following steps that hydrogen peroxide and sodium chlorate are sequentially added into coarse gold powder in a hydrochloric acid solution to carry out potential-controlled chlorination gold separation, so that gold is dissolved into the solution in the form of chloroauric acid; sodium sulfate and sodium hydroxide are added into gold separation liquid to adjust the pH value, and silver and lead are precipitated when the solution is cooled; and sodium sulfite and sodium hydroxide are added into the neutralized solution, meanwhile, the pH value and the potential of the solution are controlled, so that the precipitated gold powder is reduced, and the reduced gold powder obtained after solid-liquid separation is washed with pure water, an ammonia water solution, a nitric acid solution and pure water in sequence to remove impurities. The method has the advantages that the essence lies in that the purification of the go