Industrial Cyanide Use

Cyanide is a widely used and valuable industrial chemical. According to the World Health Organization, over one million tons of cyanide (about 80 percent of the annual production of cyanide compounds) is used in the chemical industry for production of organic chemical such as nylon and acrylics, in electroplating, metal processing, and photographic applications.

	Locations of Known Cyanide Users, Processors, Manufacturers, Distributors and Cyanide Waste Receivers and/or Generators

	Number of Known Cyanide Users, Processors, Manufacturers, Distributors and Cyanide Waste Receivers and/or Generators per 1,000 persons by County

Types of Cyanide Used in the Industry

Hydrogen Cyanide
Hydrogen cyanide is by far the most widely used in the chemical industry. Hydrogen cyanide is used primarily as an intermediary in industrial processes that result in products used in building construction, transportation vehicle interiors and residential or commercial building interiors and furnishings. Man-made end products include nylon, rayon, polyvinyl chloride, modacrylic, polyurethane foam, polyester wadding, neoprene foam, rubber, plastics, Styrofoam, insulation and adhesive resins.

Sodium Cyanide
Sodium cyanide is extensively employed in a large number of industrial processes, including electroplating and case-hardening of metals; the extraction of gold and silver from ores; base metal flotation; coal gasification; and the fumigation of ships, railroad cars, buildings, grain silos, flour mills, seeds in vacuum chambers, and soil.

The most prevalent uses for sodium cyanide is in the mineral processing industry, where it has been used for more than 100 years. One of the reasons for the high value placed on gold is its resistance to attack by most chemicals. One exception is cyanide, which dissolves the precious metal, which is most important when gold-containing ores are comprised of finely divided gold particles locked up within other minerals. Read more information on the use of cyanide in gold mining.

Potassium cyanide
Potassium cyanide is used for electrolytic refining of platinum, for metal coloring, and as an electrolyte for the separation of gold, silver, and copper from platinum

Cyanide salts
Cyanide salts are used as chelating agents, and the complex cyanides of copper, zinc, and cadmium are used in electroplating processes, principally the plating of iron, steel, and zinc

Calcium cyanide
Calcium cyanide is used chiefly as a fumigant, because it readily releases hydrogen cyanide when exposed to air; as a fertilizer, defoliant, herbicide, and rodenticide; as a stabilizer for cement; and in stainless steel manufacture

Other forms of cyanide and their uses:

• Cyanogen is used as a fumigant, as a fuel gas for welding and cutting heat-resistant metals, and as a rocket and missile propellant
• Cyanogen chloride is used as a fumigant gas and as a reagent in chemical synthesis
• Cuprous cyanide is used in plating baths for silver, brass, and copper-tin alloy plating as an antifouling agent in marine paint, and as an insecticide and fungicide
• Potassium silver cyanide is used in silver plating and as a bactericide
• Potassium ferricyanide is used chiefly for blueprints, in photography, for staining wood, in calico printing, and in electroplating
• Sodium ferrocyanide is used in ore flotation, as an anti-caking agent in rock salt, and in photography for bleaching, toning, and fixing
• Sodium nitroprusside has been used as an antihypertensive agent and in congestive heart failure and is used for deliberate induction of hypotension during certain neurosurgical procedures

Industrial Cyanide Use and the Environment

The releases of cyanide into the environment are diverse. Releases to air include chemical manufacturing and processing industries, such as metallurgical industries and metal plating, and extraction of gold and silver from low-grade ores. Other sources include volatilization from cyanide wastes disposed of in landfills and waste ponds, emissions from municipal solid waste incinerators, biomass burning, fossil fuel combustion, including vehicle emissions, fumigation operations, and the production of coke or other coal carbonization procedures.

Rules and Regulations

The U.S. Environmental Protection Agency (EPA) has requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management for those who handle hazardous materials such as cyanide.

The EPA also regulates the levels of cyanide that are allowable in drinking water. The highest level of cyanide allowed in drinking water is 0.2 parts cyanide per 1 million parts of water (0.2 ppm).

The Occupational Safety and Health Administration (OSHA) has set a limit for hydrogen cyanide and most cyanide salts of 10 parts cyanide per 1 million parts of air (10 ppm) in the workplace.

Since rules and regulations are always changing it is important to always refer the newest guidelines.