| 摘要 |
PURPOSE:To recover easily gold and silver in short time with good purity by adding a conductive salt and reducing agent to a waste stripping liquid of gold plating and controlling the potential of a cathode to electrodeposit silver first then to electrodeposit gold. CONSTITUTION:A conductive salt such as sodium hydroxide and reducing agent such as formalin soln. are added to a waste stripping liquid of gold plating which is alkaline and has free cyan and oxidizing agent as well as co-existing gold and silver in order to permit the electrolytic treatment thereof. The potential of a cathode is first controlled to the low potential range where silver deposits mainly to electrodeposit silver then the potential of the caqhode is controlled to the high potential range where gold deposits mainly to electrodeposit gold in the stage of subjecting such waste liquid to an electrolytic treatment. The electrodeposited materials having a high ratio of silver and gold are thus respectively obtd.
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