Magnesite
Magnesite is primarily a pale white mineral that has many industrial uses because of its heat resistance, it is also used in the making of attractive jewellery.
Magnesite is a mineral found as a natural ore with a similar crystal structure as calcite and identified as being magnesium carbonate (MgCO3). It often forms when rocks rich in magnesium such as dolomite, or serpentine, become exposed to water, rich in carbon dioxide. Magnesite is rather hard and can be likened in this way to marble and turquoise. It most often has a dull white appearance about it, much like porcelain before it is glazed. However, the colour of magnesite can not be relied on as it can appear quite colourless or, pink, tan, gray even yellow as it is very porous and can absorb colour from other sources. This makes it popular among jewellery makers as it will readily absorb dye that can make it appear to be turquoise. It is so porous in fact that when licked with your tongue you will find it tends to stick. It is also very fluorescent and particularly susceptible to ultra violet light. It has many industrial uses as well as being an ingredient in the production of fireworks and Epsom salts.
There is no Relationship Between Magnesite and Turquoise
Magnesite has no relationship to turquoise whatsoever despite it often erroneously being referred to as a type of turquoise. Turquoise is a phosphate and contains copper. Magnesite does not, although it does have a web like pattern to it that can easily be mistaken as the matrix that is dominant in turquoise. Cunning jewellery manufacturers can make magnesite appear to be the more expensive turquoise and it is very hard to pick any difference between the real thing. Often the only way of knowing it could be magnesite is the lower price the piece is being offered at.
Magnesite has Many Industrial Uses
Industrially, magnesite is often used with lime to form slag in furnaces associated with the production of steel to protect the magnesium lining of the furnace. It can also be used in the production of fertilisers and in the making of magnesium chemicals. In much the same way lime is produced magnesite is able to be burnt in conjunction with charcoal to make periclase (MgO). Periclase is an important ingredient in the production of refractory materials, non metallic materials that can absorb very high temperatures.
Raw magnesite is found in two different forms, cryptocrystalline and crystalline. Cryptocrystalline is more purer than crystalline and is usually associated with a silica content that gives it an off white colour. This type of magnesite is used for the following;
- The production of certain chemicals, pharma chenicals, mosaic applications, animal feeds and fertilisers
- The manufacturing of caustic calcined magnesite
- The manufacturing of dead burnt magnesite
Dead burnt magnesite is almost entirely used in the making of refractory materials such as basic refractory bricks which are used by industry for the following purposes:
- Coating in the steel industry
- SLAG splashing in arc furnaces and SLAG beneficiation
• Magnesite mortar and fettling material as well as in the making of ramming mass composition
Magnesite that is lightly calcined is chemically reactive and used in:
- Animal feeds
- Fertilisers
- Boiler lagging
- Magnesium chemicals
- The polishing industry in the form of abrasive bricks for grinding
- The grinding wheel industry in the form of Sorel cement used in binding abrasives
- The building industry in Oxy chloride flooring
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.
