Sodium cyanide-50KG

Sodium cyanide is a poisonous compound with the formula NaCN. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its high reactivity toward metals. It is a moderately strong base. When treated with acid, it forms the toxic gas hydrogen cyanide:

Sodium gold cyanide

Sodium cyanide is used mainly to extract gold and other precious metals in the mining industry. This application exploits the high affinity of gold(I) for cyanide, which induces gold metal to oxidize and dissolve in the presence of air (oxygen) and water, producing the salt sodium gold cyanide (or gold sodium cyanide) and sodium hydroxide:

4 Au + 8 NaCN + O2 + 2 H2O → 4 Na[Au(CN)2] + 4 NaOH

A similar process uses potassium cyanide (KCN, a close relative of sodium cyanide) to produce potassium gold cyanide (KAu(CN)2). Few other methods exist for this extraction process.

Sodium cyanide is used in extracting gold and silver from their ores. It forms soluble complexes with these metals. Other uses are in electroplating baths, heat treatment of metals, fumigation, and preparing other cyanide salts and complexes.