Can I borrow your broken gold necklace for my chemistry lab?

Resumo

A laboratory experiment on the recovery of gold from an obsolete piece of jewelry was developed. The gold leaching system consists of K₃[Fe(CN)₆] (potassium ferricyanide), NaCl (sodium chloride), O₂ (oxygen) and NaOH (sodium hydroxide); K₃[Fe(CN)₆] acts as a nontoxic source of cyanide, as well as an oxidizing agent (along with oxygen). Dicyanoaurate ([Au(CN)₂]-) obtained in this process is isolated and characterized by spectroscopic methods. Due to the relative simplicity of this operation and the low toxicity of the reagents required, it can be performed in any educational laboratory. This experiment gives students practice with leaching processes, which are of great importance in the mining industry.