Silicon Metal is known as a semi-metallic or metalloid, having several of the characteristics of metals. It is the second most abundant element in the Earth’s crust after oxygen, naturally occurring in various forms of silicon dioxide or silicates and very rarely in its pure form in volcanic exhalations. It takes its name from the Latin Silicus, which means flint.Silicon can be found in the form of sand, quartz, rock crystal, amethyst, agate, flint and opal as an oxide. Granite, asbestos, feldspar, clay, mica are a few examples of the numerous silicate materials. Silicon is abundant, relatively easy to mine and is one of Man’s most useful elements.
Properties of Silicon Metal
Most metallurgical silicon metal is used as an alloying agent in the aluminium industry due to its ability to increase the strength of aluminium. Demand from the aluminium industry has grown steadily in recent years due to increased usage of aluminium in structural engineering, aircraft manufacture and the automotive industry. Aluminium alloys are lighter and more resistant to corrosion than carbon-steel and can be made by addition of metals such as copper, zinc, magnesium, manganese as well as silicon.
Production of Silicon Metal
On a commercial scale metallurgical silicon metal is produced by the carbothermic reaction of silica (quartz) in an electric arc furnace using carbon electrodes where the temperature in the main reaction zone of temperatures exceeds 1800ºC. Commercially produced metallurgical grade silicon metal is typically Si 98% pure and is notably produced in China, Russia, Brazil, Norway, South Africa and USA.
Uses of Silicon Metal
Adding Silicon Metal to aluminium alloys makes them strong and light. As a result they are increasingly used in the automotive industry to replace heavier cast iron components. This allows weight reductions, a reduction in fuel consumption, increased efficiencies and subsequent benefits to the environment by reducing the greenhouse gas emissions and conserving fossil fuels.
There is increasing demand for Silicon Metal from the solar power generating industry where solar panels are made from silicon, which use the sun’s energy to produce domestic and industrial electricity. Silicon based polymers are also used as alternatives to hydrocarbon based products. They can appear in many every day products such as lubricants, greases, resins, skin and hair products. A more well known use of silicon is silicon chips, produced from semi-conductor grade silicon they are components in many every day electronic devices.