what is the rule of dilute NaCN in extracting of gold
Role of NaCN in extraction of gold is as follow:
NaCN is used in leaching of gold.
In this process, finely powdered gold is treated with dilute solution of NaCN, a current of air is passed. As a result gold pass into solution forming soluble complex cyanides while the impurities remain unaffected which are filtered off.
4 Au + 8KCN + O2 + 2H2O → 4K[Au(CN)2] + 4KOH
