用王水將化金後,點先可以收回足金呢

用電解可把王水和金分開。

displacement reaction
you can put some metel which reactvity series is higher than gold e.g Fe Cu Mg......
because other metel wil first change to be ion so that the AuNO3 and Au2SO4 will become some other salt
the reac will be
2AuNO3+Mg=Mg(NO3)2+2Au
and
Au2SO4+Mg=MgS04+2Au

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用電鍍可以回收足金
只需要化金水就得啦~
通電時....會有足金出現係陰極(無論乜電極)上,因為金離子會優先放電(放棄電荷)
陽極會出現氧氣或者氯氣(王水生成既金化物係氯化金同硝酸金)
要睇金化物濃度而決定出乜氣體
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我只係知道珠寶行業會用來鍍金,不過回收純金用呢個方法都得
但好似無聽過由k金->純金,因為純金易變形,唔會用來做飾物..