Iron ores are minerals found within the Earth's soil that create
iron (Fe) particles via heat and the process of reduction. They consist of iron
oxides which are the principal source for iron required by global iron industries,
and steel industries.
The majority of iron ores are used for steelmaking. Specifically,
approximately 98 per cent of all iron ores produced are used to manufacture
steel related products. Iron is a key element in a variety of commodities such
as:
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Magnets
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Auto parts and equipment
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Machines and equipment used
within the construction industry
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Medicine
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Paints
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Plastic products
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Cosmetics
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Insecticides
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Water purification systems
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Kitchenware and home
appliances
Several iron ores exist within the Earth's soil. They include:
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Hematite or haematite
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Magnetite
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Taconite
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Goethite
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Limonite
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Siderite
However, the most popular forms utilized by the mining industry
are hematite ores, and taconite ores, the latter form being a type of
magnetite.
Taconite ores are fragments of sedimentary rock that contain
layers alternating between chert, or carbonate, and magnetite. The particles of
magnetite are used to produce iron, and are sometimes extensively beneficiated
to create hematite.
The term taconite is often used to refer to banded iron formations
(BIFs). These types of sedimentary rock, usually abbreviated as BIFs, were
formed during the Proterozoic Eon, and are found internationally. BIFs are the
main resource for hematite ores, as they are known to contain impressive deposits
of hematite.
Hematite ores contain iron grade levels from 40 to 70 per cent Fe.
Hematite comes in an assortment of forms such as:
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Kidney ore
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Martite
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Specularite
Regardless of the type, all hematite ores are similar in colour as
each are usually within the colour range of orange and red.
Hematite ores are considered to have an efficient mining and
separation process when compared to other iron ores. For this reason, hematite
ores are known as direct shipping ores (DSOs). Once extracted and procured, hematites
can also immediately be delivered to fabricating companies. On the other hand,
it is also for this reason that hematite ores tend to carry more impurities in
contrast to other iron ores, like magnetite.
Taconite ores containing fine traces of magnetite are commonly
extracted in areas within North America. The Labrador Trough is a massive area
within Canada concentrated in taconite deposits. It spans Ungava Bay, Quebec,
and Labrador, and is recorded at 1,600 kilometres (km) long and 160 km wide.
Although taconite ores have low iron grade levels, about 30 per cent
Fe, these ores are capable of producing iron products with grades of about 60
to 70 per cent Fe. However, these high grade levels of iron are only achievable
by taconite ores that have first been beneficiated. The process of separating
commercially useable iron minerals from waste materials known as gangue, is a
noticeably more demanding process in taconite and magnetite ores than in
hematite ores. The process usually includes:
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Crushing
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Screening
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Grinding
At this point, the magnetite or taconite ores are passed through a
magnetic separator, are filtered, and dried. While this process is far more
extensive than that of hematite ores, it offers fewer impurities.
The iron ores hematite, magnetite, and taconite are all long
standing sources for iron mining industries. These ores have a variety of
benefits such as the ability to produce products with high iron grades.
Depending on factors like time and money, as well as the purpose of the final product,
certain ores are more ideal than others. It is important to understand the
similarities and differences between each in order to know which ore form is
most appropriate for a specific product.