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Sodium cyanide

Summary

Sodium cyanide is an important chemical that has been manufactured in Australia since the late 1980s. There are now three plants.

Sodium cyanide is also known as cyanide of sodium, cymag, hydrocyanic acid sodium salt. It is a white powder or solution in water. Liquid cyanide contains 30 per cent cyanide while the solid is 98 per cent pure in Australia (though lower grades are produced overseas).

Sodium cyanide (NaCN) is a chemical used overseas predominantly in metal plating and chemical applications such as dyes and pharmaceuticals. In Australia it is principally used for the gold mining industry to extract gold from gold bearing ore using the carbon-in-leach and carbon-in-pulp processes with 98 per cent of Australia’s gold production dependent on it. These processes enable commercial recovery of gold at very low concentrations (down to just 0.85gm per tonne or 0.85 ppm of soil or mine tailings). Between 300 and 500 tonnes of sodium cyanide (valued at ca. US$0.7m) is required for each tonne of gold (valued at say $13m) produced so that cyanide represents around 8 per cent of the value of gold produced.

Sodium cyanide is also used in nickel production as an arsenic suppressant.

Notes:

- About 90 per cent of Australia’s gold reserves are non-alluvial providing 98 per cent of production. Less than 1 per cent of Australia’s gold production does not use sodium cyanide.

- Acid thiourea has been used as an alternative to sodium cyanide but this is unsuitable for use in soils with soluble iron and clays as typical of Australia.

- Sodium cyanide extraction has replaced the mercury amalgam process which is environmentally harmful and less than two-thirds as efficient. A small amount of sodium cyanide is also used in electroplating and metal cleaning baths, metal hardening and insecticides.

Ticor is believed to be using technology less demanding of ammonia.

Production at all three production centres is at around world scale using the latest technology having been established in the last ten years.

Australian Gold Reagents (AGR)

link

Ticor Chemical Company

This operation was closed in April 2004 and the site sold in July 2004.

Ticor Chemical Company is located at Yarwun near Gladstone, Queensland. the plant was commissioned in 1991 and in 1994 DuPont acquired a 50 per cent interest. Like its nearby located competitor ICI, it generally produces the dry form of sodium cyanide with a production capacity of about 40 000 tonnes tpa and is now 100% owned by Ticor. The company employs about 75 persons. The required raw materials are purchased on the open market.

Production of briquettes are 15gms, 31mm by 30mm by 11mm with a specific gravity of 1.6 and a minimum of 98 per cent purity (0.2% water maximum). The cyanide is packaged in 1 000 kg Intermediate Bulk Containers of plywood.

Orica

Orica operates a plant at Yarwun (close to the Ticor operation) with a production capacity of about 35 000 tpa of dry cyanide. Ammonia is road freighted and shipped. 

Application

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Demand

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Price

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Trade

Imports

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Exports

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Production

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Technology

Sodium cyanide is manufactured by the Andrussow process using ammonia, natural gas, air, and caustic soda. The process reacts ammonia with natural gas and air over a platinum/rhodium catalyst to produce hydrogen cyanide gas.

Raw Materials

Ammonia

The production of 1 tonne of sodium cyanide requires:

-  0.65 tonnes oa ammonia.

Caustic Soda

The production of 1 tonne of sodium cyanide requires:

-  0.95 tonnes of caustic soda

Natural Gas/Air

The production of 1 tonne of sodium cyanide requires:

- 36 gigajoules of natural gas/...more coming soon...of air

Electricity

- 0.67 megawatts of electricity