By changing the proportions of these additional elements, it is possible to make steels suitable for a great variety of uses. The table below shows the special properties and uses of some iron compounds.
Steel buildings, bridges such as the Sydney Harbour Bridge , reinforcing in concrete buildings, roofing, cladding, doors, fencing. Animals need iron for making energy and carrying blood around the body foods rich in iron include red meat and liver, egg yolks and leafy green vegetables.
Iron was the first element to be recognised as essential for people. A physician in successfully used iron to treat patients who were pale, lacking in energy and suffering from anaemia.
Iron is among the oldest metals known to humans. Paleolithic Man used finely ground haematite as body paint. Around BC, the Egyptians and Sumerians first used iron from meteorites to make beads, ornaments, weapons and tools. The time line of Iron Age varied geographically; for instance the Hittites forged iron they heated it, then hammered it, then cooled it quickly to produce iron that was harder than the bronze that people had been using before around the period of - BC and similarly according to Tewari , archaeological evidence indicates iron working in India occurred around to BC.
By the time of the Roman Empire, iron was being used for beds, gates, chariots, nails, saws, axes, spears, fishhooks and tools for sharpening. During the Middle Ages, with the introduction of the iron cannon and cannon ball, the consumption of iron increased to overtake copper and bronze as the most widely used metal.
In the late 19th century the Age of Steel began, with wooden ships giving way to steel, machinery coming to factories and the invention of the railroad. Iron is indispensable to modern civilisation and people have been skilled in its use for more than 3, years.
However, its use only became widespread in the 14th century, when smelting furnaces the forerunner of blast furnaces began to replace forges. Iron ores are rocks from which metallic iron can be economically extracted. Most deposits of iron ore in the world are found in rocks known as banded iron formations BIFs. These are sedimentary rocks that have alternating layers of iron-rich minerals and a fine-grained silica rock called chert.
Many of the banded iron formations that are being mined today were formed millions of years ago. About million years ago there was no or very little oxygen dissolved in the oceans. However, the oceans did contain a lot of dissolved silica, which came from the weathering of rocks.
Every now and again this silica precipitated out from the seawater as layers of silica jelly, which slowly hardened to become the rock we call chert. Soluble iron oxide was also produced from the weathering of rocks and was also washed into the sea by rivers. About million years ago the oceans were inhabited by bacteria that developed the ability to photosynthesise and produce oxygen. There were seasonal 'blooms' that released huge amounts of oxygen into the seawater that reacted with the soluble iron oxide to form insoluble iron oxide.
This precipitated out of solution as the minerals magnetite and hematite forming layers of iron among the other layers of sediment on the sea floor.
Over many millions of years these processes of precipitating silica and iron oxide were repeated over and over again resulting in the deposition of alternating layers of chert, hematite and magnetite. The name banded iron formation comes from the characteristic colour banding of these huge deposits. The process continued for nearly a billion years and eventually let to the accumulation of oxygen in the atmosphere.
Most of the world's important iron ore resources occur in banded iron formations, which are almost exclusively of Precambrian age i. Also minor production of micaceous hematite. Pyrite FeS was mined at Brukunga to make sulfuric acid, which in turn was used, for the manufacture of superphosphate.
The ore was formed by supergene enrichment of host BIF with both structural and mineralogical controls on ore distribution. Since then some Mt of high-grade ore has been mined from five massive hematite deposits in the Middleback Range. From to the Iron Monarch and Iron Baron-Iron Prince mines were the main supply of ore for Australia's iron and steel industry. The favourable logistics of low cost of ore extraction and the nearby portsite at Whyalla, led BHP to establish an integrated steelworks at Whyalla in Iron Baron was closed in and Iron Monarch was closed in Both these mines and the Iron Princess north of the Iron Monarch , and the Iron Cavalier are in the process of being recommissioned.
In BHP Steel Pty Ltd divested itself of all long products businesses which included the Whyalla operations and its attached iron ore resources. From this announcement OneSteel emerged as a totally independent competitive steelmaker and miner. With OneSteel further rationalising its operations with the emergence of Arrium Mining, a dedicated exporter of iron ore, and supplier of iron ore to OneSteel's integrated steelworks at Whyalla.
Arrium are the current major producers of iron ore from massive hematite deposits in the South Middleback Range. Limited outcrop and drilling has confirmed that the source of the anomalies is a magnetite-rich ironstone, commonly a BIF.
These BIFs are described below in order of age. Wilgena Hill Jaspilite, Middleback Ranges. It generally has a strong magnetic signature particularly so in Middleback Range, a discontinuous series of strike ridges of BIF extending north-south for 60 km. The source of the magnetic anomaly has been identified as magnetite-rich BIF beneath a cover of haematitic BIF averaging 90m thick. Returning to the Eyre Peninsula, there has been considerable resource drilling by several companies throughout the whole of the Eyre Peninsula on rocks of magnetite-bearing BIF.
Indeed the Eyre Peninsula region has been confirmed as a major iron ore province in South Australia. Drilling at the Warramboo prospect has identified the source as a metasedimentary magnetite-bearing gneiss of granulite facies, possibly originally a BIF. Beneficiation testwork by a relatively simple grinding and wet magnetic separation process yielded a grade suitable for use in the production of DRI direct reduced iron feedstock.
Published resource is 3. The Mount Woods Inlier contains considerable strike lengths of linear magnetic anomalies attributed to both BIF and magnetite-rich metasomatite, which interpretation has been confirmed by drilling.
There has been little exploration of these BIFs for iron ore. IMX Resources in drilled their Tomahawk prospect, and confirmed the source of the magnetic anomaly as a magnetite-bearing BIF.
The Ooldea prospect lies on a magnetic anomaly associated with the Karari Fault Zone. The magnetic signature of the Karari Fault persists discontinuously for km to the northeast. Braemar ironstone facies occurs as a stratigraphic package of magnetite-rich ironstone associated with diamictite and is located in the Nackara Arc region of the Adelaide Geosyncline. The rock has been described as 'Rapitan'-type BIF i. Its iron ore potential was assessed in the early s at the Razorback Ridge prospect.
It is non-magnetic and has colour variations ranging from steel silver to reddish brown. Pure mineral hematite contains The Brockman Iron Formation in the Hamersley province contains significant examples of high-grade hematite iron ore deposits. Magnetite is another iron oxide mineral. It is generally black and highly magnetic, the latter property aiding in the beneficiation of magnetite ores. Mineral magnetite contains Magnetite mining is an emerging industry in Australia with large deposits being developed in the Pilbara and mid-West regions of Western Australia, and in South Australia.
High-grade hematite ore is referred to as direct shipping ore DSO because after it is mined, the ores go through a relatively simple crushing and screening process before being exported for use in steelmaking.
Like hematite ores, magnetite ores require initial crushing and screening, but undergo a second stage of processing that relies on the magnetic properties of the ore and involves magnetic separators to extract the magnetite and produce a concentrate. Further processing involves the agglomeration and thermal treatment of the concentrate to produce pellets that can be used directly in blast furnaces, or in direct reduction steel-making plants.
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