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  2. Gold extraction - Wikipedia

    en.wikipedia.org/wiki/Gold_extraction

    The expansion of gold mining in the Rand of South Africa began to slow down in the 1880s, as the new deposits being found tended to be pyritic ore. The gold was difficult to extract from such ores. A process known as chlorination was once used to treat pyritic gold ore. Typically, the ore was roasted and then treated with chlorine gas. The ...

  3. Gold parting - Wikipedia

    en.wikipedia.org/wiki/Gold_parting

    Invented by Emil Wohlwill in 1874, the Wohlwill process produces the highest purity gold (99.999%). It is an electrolytic process using pure gold for the cathode (or titanium as a starter cathode) and chloroauric acid (gold chloride-hydrochloric acid) as the electrolyte; this is made by dissolving gold with chlorine gas in the presence of ...

  4. Wohlwill process - Wikipedia

    en.wikipedia.org/wiki/Wohlwill_process

    The Wohlwill process is an industrial-scale chemical procedure used to refine gold to the highest degree of purity (99.999%). [1] The process was invented in 1874 by Emil Wohlwill. This electrochemical process involves using a cast gold ingot, often called a doré bar, of 95%+ gold to serve as an anode.

  5. Electrowinning - Wikipedia

    en.wikipedia.org/wiki/Electrowinning

    Electrowinning is the oldest industrial electrolytic process. The English chemist Humphry Davy obtained sodium metal in elemental form for the first time in 1807 by the electrolysis of molten sodium hydroxide. Electrorefining of copper was first demonstrated experimentally by Maximilian, Duke of Leuchtenberg in 1847. [2]

  6. Gold cyanidation - Wikipedia

    en.wikipedia.org/wiki/Gold_cyanidation

    Other metals are recovered from the process include copper, zinc, and silver, but gold is the main driver of this technology. [1] Due to the highly poisonous nature of cyanide, the process is controversial and its use is banned in some parts of the world. Cyanide can be safely used in the gold mining industry. [3]

  7. Hydrometallurgy - Wikipedia

    en.wikipedia.org/wiki/Hydrometallurgy

    Metal recovery is the final step in a hydrometallurgical process, in which metals suitable for sale as raw materials are produced. Sometimes, however, further refining is needed to produce ultra-high purity metals. The main types of metal recovery processes are electrolysis, gaseous reduction, and precipitation.

  8. Electrolytic process - Wikipedia

    en.wikipedia.org/wiki/Electrolytic_process

    The video describes the electrolytic process as it is occurring on Captain Kidd's Cannon, which is on display and currently undergoing the electrolytic process. An electrolytic process is the use of electrolysis industrially to refine metals or compounds at a high purity and low cost. Some examples are the Hall-Héroult process [1] used for ...

  9. Electrolysis - Wikipedia

    en.wikipedia.org/wiki/Electrolysis

    The key process of electrolysis is the interchange of atoms and ions by the removal or addition of electrons due to the applied potential. The desired products of electrolysis are often in a different physical state from the electrolyte and can be removed by mechanical processes (e.g. by collecting gas above an electrode or precipitating a ...