Sodium Cyanide

Sodium cyanide is used throughout the world, primarily as a reagent in the mining industry for the isolation of precious metals. Close to 90% of sodium cyanide is used for gold and silver processing in North America and around 78% is used for this purpose worldwide. However, it also has use as a chemical intermediate, especially in regions where there is not a local supply of hydrogen cyanide, since sodium cyanide can be transported and stored. In Japan and Europe, chemical uses predominate, while in North and South America, Australia, South Africa, and China, use for gold extraction is the major application. There is substantial world trade in solid sodium cyanide, with the United States, the Republic of Korea and Australia as the major exporting nations. Mexico, China, South America and West Africa are exhibiting relatively higher growth than the rest of the world. 

The sodium cyanide market has changed quite a bit in recent years as a result of the impressive rise in gold prices. Gold mining companies have been investing capital in new grassroots exploration projects, as well as prolonging activities in mines that had been winding down. Some of the operations that had been shuttered have also been restarted. This has resulted in increased demand for sodium cyanide and growth is expected to continue during the forecast period, depending on continuing operations at the gold mines. However, it is possible that consumption could decline over the next five years as a result of a combination of factors. Increasing delays and impediments in starting up large-scale projects could impact consumption, as would investment in capital costs. The ongoing global financial crisis may cause people to invest more in gold, thus creating demand, but mining companies may find it difficult to finance projects. Exploration efforts for both expansions and new projects continue, but there are relatively few new areas that are available for gold exploration and production. A decrease in gold production also increases the potential of higher long-term gold prices. 

The following pie chart shows world consumption of sodium cyanide:

There is pressure in many regions worldwide to ban the use of sodium cyanide in the recovery of gold. Montana and Wisconsin have legislated that there can be no new operations involving sodium cyanide but existing operations are grandfathered in. There have been instances of accidents and spills involving sodium cyanide that prompted a voluntary industry program known as the International Cyanide Management Code for the Manufacture, Transport and Use of Cyanide in the Production of Gold (ICMC). The ICMC was developed under the auspices of the United Nations Environmental Program (UNEP) and the International Council on Metals & the Environment (ICME). In May 2000, at a joint UNEP/ICME-sponsored international workshop in Paris, cyanide producers, regulatory and transportation personnel, gold mining companies and environmental advocacy organizations around the world gathered to form a steering committee that would create the ICMC. The first draft was published in May 2002. After several rounds of negotiations and reworking, the final form was ready in 2006. Signatories to the code agree to the highest standards of practice for manufacturing, transportation and use of cyanide. Major global gold producers, transporters and suppliers of cyanide products have signed the ICMC, which includes third-party auditing and certification of the facilities every three years. Currently, there are 121 mines, cyanide producers and transporters that are signatories. The ICMC is administered by the International Cyanide Management Institute.

There are several precious metal chemical isolation techniques that do not utilize sodium cyanide (thiourea and thiocyanate processes). Haber, Inc., based in Towasco, New Jersey, has a technology (HGP Process) for the extraction of gold from ores that uses an unidentified nontoxic solvent. Sodium bromide has been used at pilot-plant levels and reportedly results in relatively better "eco-friendly" waste by-products. However, none of these technologies has proven to be notably competitive or more environmentally friendly than sodium cyanide. Though significant work has been done to improve the gold extraction process, successful and advantageous alternates to sodium cyanide have yet to emerge that are economically viable or more environmentally friendly.

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