Uses of Gold
Gold and silver have many uses. According to the estimations of GoldFields Mineral Services, in 2016, 3,168 tonnes of gold have been produced worldwide. Approximately 80% of this production is absorbed by goldsmiths. Greece imports approximately 12 tonnes of gold per year for the manufacture of jewellery, and approximately 40,000 people are employed in this field. However, gold is not only a “precious metal”, it is many more things:
- It is an excellent conductor of electricity
- It is resistant to corrosion
- It is almost completely indestructible and yet quite malleable
- It is non toxic, and non carcinogenic
- It is one of the most efficient heat reflecting means
Some other uses of gold, per sector, are the following:
Electronics and Telecommunications
Due to the fact that gold is an excellent conductor of electricity, it is used:
- In computers and semiconductors.
- In automatic wheelchairs for disabled persons.
- In the sensors of the automotive airbags, where it ensures that they will operate when they must during the entire lifetime of the vehicle.
- For the protection of computers against short circuit which can be caused by strong ion charges.
- In the covers of transmitters in telephone devices for their protection against corrosion.
- In television and video apparatus, where microcircuits consist of thin gold fibers.
Lasers and Optical Equipment
- In astronomical telescopes gold is used for covering secondary mirrors due to its great reflectivity in the infrared spectrum
- In photocopiers. These apparatus use gold-plated mirrors for the effective reflection of the heat that is used for the generation of images.
- In photo CD. The Hartman Kodak company has developed a photo CD system that uses gold as reflection surface.
- In satellites, electronic circuits and reflective sheets made of gold.
- In security systems, that require infrared night rays of high reliability. Security cameras use gold for their reflective properties.
Medicine and Health
Gold is valuable in modern medicine because it is not toxic and is biologically benign.
- In dentistry, gold is principally used in the form of alloys. In the USA, approximately 13 tonnes of gold are used annually for dental bridges, fillings and dentures.
- In ophthalmic surgery, gold is used in the lagophthalmos disorder, which is the inability to close the eyelids completely. Gold is implanted in the eyelids to help them close.
- In lasers. The new gold diffusion lasers achieve a high intensity beam with the required wavelength, which searches for and destroys selectively cancer cells without causing any harm to the healthy neighboring cells.
- In the treatment of rheumatoid arthritis. Gold is used for the treatment of rheumatoid arthritis since the 1920s and consists the primary treatment since the 1960s. According to research, it seems that gold affects the process that causes the simultaneous occurrence of pain and swelling.
- In thermometers. A new type of thermometer has been created that contains gold, which measures the temperature of the human body in two seconds just by holding it on the outer ear. It is a non invasive method for monitoring the body temperature which is particularly useful in babies or patients.
- In scientific research. The connection, in the laboratory, of tiny gold particles with DNA has created new microscopic structures that allow for a large-scale research, treatment and diagnostic capacities in sectors such as biochemistry, genetics and medicine.
Industry and aviation
- In aircraft engines
- In aircraft windows
- In the research for response to the air pollution
- In car paint drying furnaces
- In various mechanical systems
- In fire shelter equipment
- In food freshness sensors, etc.
Information on Cyanide
Cyanide is a natural compound that molecularly consists of carbon and nitrogen. The Gold mining industry uses cyanide for the extraction of gold for many decades now.
Cyanide is a chemical which is widely used and is necessary in the modern world. Over 1,300,000 tonnes of cyanide are produced every year. It is used in many industrial applications, while only 18% of the cyanide world production is used in mining industry.
As many other substances (e.g. alcohol), it can be fatal when it is taken in high concentrations, but does not cause any chronic disease or environmental problem when its concentrations are low.
Cyanide is rapidly degraded through natural, chemical and biological processes and does not remain stable in the environment.
Cyanide is not carcinogenic or radioactive, does not cause mutagenicity or teratogenicity, as it can be seen in publications of the World Health Organization (WHO) and the Center for Disease Control (CDC) of the USA, here:
It does not belong to heavy metals, it is not bio-accumulative and must not be related with acid drainage. Cyanide can be prepared, stored, transported and used with safety.
In metallurgy, a cyanide compound, sodium cyanide, is used. For most of the people the phrase “sodium cyanide” causes an immediate negative reaction. Sodium cyanide is a dry, solid, non volatile product. Although particularly toxic, it is a low-risk chemical compound, because the ways of its safe use are clarified and standardized. It can be easily transported and safely used, whether in the solid form or in a solution form, by taking the appropriate measures. Sodium cyanide can become a safe and effective reagent in many industrial activities.
Natural Occurrence of Cyanide
Cyanide is formed naturally. It is produced and used by plants and animals.
The compound of hydrogen cyanide (HCN) exists in many fruits, vegetables, oysters and nuts such as apricots, broad beans, beans, soy, cashews, pistachios, cherries, chestnuts, cereal grains, lentils, nectarines, peaches, potatoes, walnuts, etc.
There are more than 2,000 natural sources of cyanide which include species of arthropods, insects, bacteria, algae, fungi and plants.
Plants such as clovers and sugar beets consist known sources of cyanide poisoning in pets and humans.
Cyanide compounds sources are everyday before us, such as automobile engine exhaust, cigarette smoke, salt, both in edible form and the one used in snow-covered roads, etc.
Industrial Uses of Cyanide
Cyanide is mainly used in chemical industry. 80% of the total cyanide production is used in the production of nitrile, nylon and acrylic plastic.
Other industrial uses of cyanide include the plating, processing and painting of metals, photographic applications, the production of synthetic rubber, leather processing, the production of farming products and agricultural medicines, the synthetic silk industry, the production of detergents, etc.
Cyanide can be also met in medicinal uses. For example, it consists a constituent of vitamin Β12 (cyanocobalamin) for the treatment of pernicious anaemia. It has been also used for the treatment of arterial hypertension in the Nitroprusside preparation and of cancer in the chemotherapy preparation Laetrile .
Cyanide compounds are used in surgical dressings for the treatment and reduction of pain.
20% of the cyanide production is in the form of sodium cyanide, a solid form that can be easily and safely used and handled.
Of this quantity, 90% (that is 18% of the total production) is used in metallurgy and principally in the extraction of gold.
Use of Cyanide in the Production of Gold
Gold mines use dilute solutions of sodium cyanide (NaCN), with a cyanide content from 0.01 to 0.05% (100 to 500 ppm – parts per million).
The dilution process of the metals with sodium cyanide is called extraction.
Gold mines use cyanide compounds for the extraction of gold for over 100 years.
In the Perama project, after the extraction that takes place in tanks, the sterile solution along with the solid waste (tailings) will be channeled to the closed Tailings Management Pond.
The processing plant will operate with the principle of zero discharge to the environment.
The destruction of cyanides will be performed with chemical oxidation with the process that has been established as the INCOTM method – (SO2 + oxygen).
The sodium cyanide management practices in the mine will be available for public update and the local communities will be able to be informed for every activity of the mine.
- Eldorado’s Kisladag mine in Turkey became ICMC certified in 2013.