Metallurgical-Silicon-Metal
Metallurgical grade silicon (Si) is a lustrous black metal used as a reducing agent in steel and iron production, a de-oxidiser and for metal alloying.
Metallurgical silicon metal is a metalloid, or semi-metallic substance having many of the characteristics of metals. Only oxygen is more abundant than silicon in the earth's crust and it occurs in nature in various forms of silicates, or as a silicon dioxide, although it is rarely found in its purest form in volcanic exhalations.
Silicon, is found primarily in sand, opal, agate, amethyst, crystal, rock, quartz and flint as an oxide. In fact the name itself is derived from the latin word 'silicus' which means flint. Silicate materials are also found in mica, clay, feldspar, asbestos and granite. It is abundant, one of the most useful of the elements and easy to mine.
Metallurgical silicon metal is mostly used as an alloying material in the aluminium industry because of its ability to add strength to aluminium products. There has been a steady growth in demand from the aluminium industry for metallurgical silicon metal owing to the increased use of aluminium in the motor car, aircraft and structural engineering industries. Aluminium alloys are more resistant to corrosion and lighter than carbon-steel, as well as being able to made with the addition of manganese, magnesium, zinc and copper, as well as silicon.
Metallurgical silicon metal is produced on a commercial scale by using carbothermic (the use of carbon as a reducing agent) reaction of quartz in an electric arc furnace using carbon electrodes. To get this reaction the temperature in the reaction area has to be over 1,800 degrees Celsius. The reaction taking place with wood, charcoal and coal inside the furnace. The liquid silicon collects in the bottom of the furnace from where it is drained and cooled. In order to receive a commercial grade result the metallurgical silicon metal has to be around 98 percent pure silicon. Most metallurgical silicon metal produced in this way is made in China, Russia, Brazil, Norway, South Africa and the USA.
The main uses of metallurgical silicon metal are as follows:
- In the motor car industry replacing heavy cast iron components. This results in weight reduction that in turn allows for lower fuel consumption and a benefit to the environment by conserving fossil fuel and a corresponding reduction in greenhouse gas emissions
- A growing demand from the solar power generation industry as solar panels are made from silicon.
- Silicon based polymers as an alternative to hydrocarbon products such as; hair and skin products, resins, grease and lubricants
- Silicon chips that are used in many popular electronic devises
There is often confusion experienced between the defining of silicate from silicon. In simple terms silicate is made up of metals such as aluminium, oxygen and silicon. On the other hand silicon is made up of different compounds. The main difference between the two is that silicon is one of the elements required to make silicate but silicate comprises silicon and other elements. Metallurgical silicon metal's primary use is in the aluminium casting industry where it is made into aluminium silicon alloy parts . Its other main uses is in the chemical industry where it is used to make fumed silica. Fumed silica is used as a thickening as well as an anti-caking agent in powders and products such as tooth paste and cat box filler.
Australian Mines that produce Bauxite
Gove (NT)
Up to 600 workers employed at the Gove bauxite refinery in the Northern Territory face an uncertain future as Pacific Aluminium suspends alumina production.
Ely (QLD)
The Ely Alcan Queensland Pty Ltd agreement at the Weipa bauxite mine is due to expire in 2041 but an option will give it a further 21 years extension.
Skardon River (QLD)
Gulf Alumina acquired 100 percent of the Skardon River tenement in 2011 from its koalin mining joint partner to develop the mining of bauxite at the site
Weipa (QLD)
The Weipa bauxite mine on the western side of the Cape York Peninsula in northern Queensland is both owned and operated by Rio Tinto Alcan.
Huntly (WA)
The Huntly mine in Western Australia is the largest bauxite mine in the world currently producing about 23 million tonnes of bauxite annually.
Willowdale (WA)
The Willowdale bauxite mine that commenced production in 1984 still processes 10 million tonnes of bauxite a year at the nearby Wagerup Refinery.
Worsley (WA)
The Worsley bauxite mine and alumina refinery in South West Western Australia employs more than 1,800 people and produces 4.6 million tonnes of alumina annually.
South Aurukun (QLD)
The South Aurukun bauxite tenements on the Cape York Peninsula in Far North Queensland are held by Gulf Alumina.
Marchinbar Island (NSW)
The Marchinbar Island bauxite deposit in far north Northern Territory could be mined to satisfy a growing demand from China in the near future.
Kwinana Refinery (WA)
The Kwinana refinery in WA employs around 1,000 direct employees with 60 percent living in the nearby towns of Rockingham, Cockburn and Kwinana.
Wagerup Refinery (WA)
The Alcoa owned Wagerup alumina refinery in W.A. has received governmental approval to lift alumina production from 2.6 to 2.65 million tonnes annually.
Pinjarra Alumina Refinery (WA)
The Pinjarra alumina refinery, near Mandurah south of Perth, is an important part of Alcoa's three refinery system in Western Australia.
Portland Aluminium Smelter (VIC)
The Portland Aluminium smelter in western Victoria, a joint venture operation between Alcoa, CITIC and Marubeni, caters solely to the Asian market.
Felicitas (WA)
The Felicitas bauxite project in Western Australia contains a bauxite resource of 220 million tonnes that will give it a life of mine of 25 years
South Of Embley (QLD)
Despite Rio Tinto placing its South of Embley bauxite project in Cape York, Queensland, on hold for 18 months it still considers it a 'good project.'
Bauxite Hills (QLD)
The Bauxite Hills Project on the Cape York Peninsula in Queensland is hoping to take advantage of an expected increase in the demand for Alumina.
Bald Hill (TAS)
Australian Bauxite Limited's Bald Hill mine, in Tasmania, is to start production in December, 2014. It is the first new bauxite mine in Australia, for over 35 years.
Urquhart Point (QLD)
The Urquhart Point Heavy Mineral Sands Project in Cape York in Far North Queensland is expected to begin production in mid-2015.
Amrun (QLD)
The Amrun bauxite project in far north Queensland, that was previously known as the 'South of Embley' project has been approved for development and expected to be in production by 2019.
