| 摘要 |
<p>A method for smelting a noble metal involving a silver treatment process comprising the steps of leaching crude silver with nitric acid, purifying the leachate, electrolyzing silver, and recirculating the liquid after the electrolysis. In the step of purifying the leachate, the leachate is neutralized by the addition of lime to precipitate and remove impurity metals, such as selenium, tellurium, bismuth, and copper. In the step of recirculation, sulfuric acid is added to the liquid after the electrolysis to precipitate and remove the lime and to restore nitric acid for reutilization. Preferably, the silver treatment process is carried out simultaneously with the gold recovering step comprising dissolving the slag formed in the leaching of crude silver with nitric acid by chlorination and recovering gold from the leachate by solvent extraction or reductive precipitation. This method facilitates preparation of high-purity gold and silver in a markedly shorter gold smelting time than that in the prior art.</p> |
