Pig-Iron
Pig iron is the metallic product of a furnace containing over 90 percent iron. The name refers to the old-fashioned way of casting iron into sand moulds.
Pig iron is the name given to the metallic product of a furnace containing more than 90 percent iron. It became known as pig iron because of the way the iron moulds stretched out either side of a runner into which blast furnace iron was poured. The runner was known as the sow and the moulds branching out from the sow were called pigs. Modern pig iron production is produced by a continuous pig casting machine. Pig iron details include the following:
Pig iron results from the smelting of iron with a high carbon fuels such as, coke, anthracite or charcoal.
Limestone is used as a flux. Anthracite is the coal with the highest coal content and lesser amount of impurities. Because of pig iron's high content of carbon, silica and any other mass of impurity that floats on the molten metal, called dross, it can be quite brittle and therefore has limited applications. For these reasons it is an intermediate product that requires further melting to enable it to be used in the producing of steel.
Raw pig iron is used in the manufacturing of wrought iron in puddling furnaces and in recent times turned into steel.
This is achieved by melting the pig iron while blowing a strong current of air over the melted metal as it is being agitated or stirred. This action causes any silicon and other dissolved impurities to become oxidised.
Pig iron can also be turned into a product known as grey iron.
This is achieved by remelting the pig iron along with scrap iron and steel, after removing the impurities alloys are added and the carbon content adjusted. Some grades of pig iron are found suitable for the production of ductile iron, commonly known as cast iron.
Pig iron/slag, produced today is poured from the bottom of a blast furnace through a trough, into a ladle car, that takes it directly to the steel mill while it is still in liquid form.
This pig iron is referred to as hot metal. It is introduced into a steel making vessel via either an electric arc furnace, an induction furnace or a basic oxygen furnace. This process burns off any excess carbon under controlled conditions while at the same time adjusts the composition of the alloy. Pig iron was used as ballast on board the NASA Boeing 747 Shuttle Carrier Aircraft.
The demand for pig iron has increased in recent times as steel makers become more and more aware of the benefits it has over alternate sources of iron.
Modern pig iron improves process control, gives optimal slag conditions, has consistent chemistry, produces a steel with low nitrogen and contains low residuals. For these reasons it attracts a premium price over that of scrap iron prices.
A blast furnace producing pig iron works continuously with the raw material being fed in small amounts every 10 or 15 minutes.
The slag is removed every two hours and pig iron tapped around five times each day. In order to tap the pig iron the refractory clay plug has to be removed from an opening at the bottom of the crucible. This allows the liquid metal to flow along a clay channel to where a skimmer separates the slag from the iron. The molten iron then enters a refractory lined railway car, some of which have a capacity to hold up to 100 tonnes of metal at the one time. These cars take the metal to the steel mill in this form or alternatively as cast iron slabs.
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.
