Download Document

IRON ORE
• Iron ores are rocks and minerals from which metallic iron can
be economically extracted.
• The ores are usually rich in iron oxides and vary in color from
dark grey, bright yellow, deep purple, to rusty red. The iron
itself
is
usually
found
in
the
form
of magnetite (Fe3O4), hematite(Fe2O3), goethite (FeO(OH)),
limonite (FeO(OH).n(H2O)) or siderite (FeCO3).
• Hematite is also known as "natural ore", a name which refers
to the early years of mining, when certain hematite ores
containing up to 66% iron could be fed directly into ironmaking blast furnaces. Iron ore is the raw material used to
make pig iron, which is one of the main raw materials to
make steel.
• 98% of the mined iron ore is used to make steel.Indeed, it has
been argued that iron ore is "more integral to the global
economy than any other commodity, except perhaps oil".
Sources
• Metallic iron is virtually unknown on the surface of the
Earth except as iron-nickel alloys from meteorites and
very rare forms of deep mantlexenoliths.
• Although iron is the fourth most abundant element in the
Earth's crust, comprising about 5%, the vast majority is
bound in silicate or more rarely carbonate minerals.
• The thermodynamic barriers to separating pure iron from
these minerals are formidable and energy intensive,
therefore all sources of iron used by human industry
exploit comparatively rarer iron oxide minerals, the
primary form which is used being hematite.
• Iron ore mining methods vary by the type
of ore being mined. There are four main
types of iron ore deposits worked
currently, depending on the mineralogy
and geology of the ore deposits. These
are magnetite, titanomagnetite, massive
hematite and pisolitic ironstone deposits.
Hematite: the main iron ore in
Brazilian mines
Stockpile of iron ore pellets will be
used in steel production.
Processed Taconite pellets as used
in the steelmaking industry, with a US
Quarter shown for scale
Banded iron formations
• Banded
iron
formations
(BIF)
are
metamorphosed
sedimentary
rocks
composed
predominantly of thinly bedded iron minerals and silica
(as quartz).
• The iron mineral present may be the carbonate siderite,
but those used as iron ores contain the
oxides magnetite or hematite.
• Banded Iron formations are known as taconite within
North America.
• Mining of BIF formations involves coarse crushing and
screening, followed by rough crushing and fine grinding
to comminute the ore to the point where the crystallised
magnetite and quartz are fine enough that the quartz is
left behind when the resultant powder is passed under a
magnetic separator.
•
•
•
•
•
•
Currently
magnetite
iron
ore
(taconite)
is
mined
in Minnesota and Michigan in the U.S., and Eastern Canada. Magnetite
bearing BIF is currently mined extensively in Brazil, which exports
significant quantities to Asia, and there is a nascent and large magnetite
iron ore industry in Australia.
Magmatic magnetite ore deposits
Occasionally granite and ultrapotassic igneous rocks segregate magnetite
crystals and form masses of magnetite suitable for economic concentration.
A few iron ore deposits, notably in Chile, are formed from volcanic flows
containing significant accumulations of magnetite phenocrysts. Chilean
magnetite iron ore deposits within the Atacama Desert have also
formed alluvial accumulations of magnetite in streams leading from these
volcanic formations.
Some magnetite skarn and hydrothermal deposits have been worked in the
past as high-grade iron ore deposits requiring little beneficiation. There are
several granite-associated deposits of this nature in Malaysia and
Indonesia.
Other sources of magnetite iron ore include metamorphic accumulations of
massive magnetite ore such as at Savage River, Tasmania, formed by
shearing of ophiolite ultramafics.
Another, minor, source of iron ores are magmatic accumulations in layered
intrusions which contain a typically titanium-bearing magnetite often with
vanadium. These ores form a niche market, with specialty smelters used to
recover the iron, titanium and vanadium. These ores are beneficiated
essentially similar to banded iron formation ores, but usually are more easily
upgraded via crushing and screening. The typical titanomagnetite
concentrate grades 57% Fe, 12% Ti and 0.5% V2O5
Hematite ore
• Hematite iron ore deposits are currently exploited on all continents
except Antarctica, with the largest intensity in South America,
Australia and Asia. Most large hematite iron ore deposits are
sourced from altered banded iron formations and rarely igneous
accumulations.
• Hematite iron is typically rarer than magnetite bearing BIF or other
rocks which form its main source or protolith rock, but it is
considerably cheaper to process as it generally does not require
beneficiation due to its higher iron content.
• However, hematite ores are harder than magnetite ores and
therefore require considerably more energy to crush and grind if
benefication is required. Hematite ores can also contain significantly
higher concentrations of penalty elements, typically being higher in
phosphorus, water content (especially pisolite sedimentary
accumulations) and aluminium (clays within pisolites).
• Export grade hematite ores are generally in the 62–64% Fe range
Production and consumption
Estimated iron ore production in million metric tons for 2009according to U.S. Geological Survey
Country
Production
China
880
Australia
394
Brazil
300
India
245
Russia
92
Ukraine
66
South Africa
55
Iran
33
Canada
32
United States
27
Kazakhstan
22
Sweden
18
Venezuela
15
Mauritania
10
Other countries
43
Total world
2240
World Mine Production and Reserves
United States
Australia
Brazil
Canada
China
India
Iran
Kazakhstan
Mauritania
Mexico
Russia
South Africa
Sweden
Ukraine
Venezuela
Other countries
World total (rounded)
Mine production
2010
2011e
50
54
433
480
370
390
37
37
1,070
1,200
230
240
28
30
24
24
11
11
14
14
101
100
59
55
25
25
78
80
14
16
48
50
2,590
2,800
Reserves
Crude ore Iron content
6,900
2,100
35,000 17,000
29,000 16,000
6,300
2,300
23,000 7,200
7,000
4,500
2,500
1,400
3,000
1,000
1,100
700
700
400
25,000 14,000
1,000
650
3,500
2,200
6,000
2,100
4,000
2,400
12,000 6,000
170,000 80,000
• Iron is the world's most commonly used metal - steel, of which iron
ore is the key ingredient, representing almost 95% of all metal used
per year.
• It is used primarily in structural engineering applications and in
maritime purposes, automobiles, and general industrial applications
(machinery).
• Iron-rich rocks are common worldwide, but ore-grade
commercial mining operations are dominated by the countries listed
in the table aside.
• The major constraint to economics for iron ore deposits is not
necessarily the grade or size of the deposits, because it is not
particularly hard to geologically prove enough tonnage of the rocks
exist.
• The main constraint is the position of the iron ore relative to market,
the cost of rail infrastructure to get it to market and the energy cost
required to do so.
• Mining iron ore is a high volume low margin business, as the value
of iron is significantly lower than base metals.
• It is highly capital intensive, and requires significant investment in
infrastructure such as rail in order to transport the ore from the mine
to a freight ship. For these reasons, iron ore production is
concentrated in the hands a few major players.
Major Producer
• CIS-Largest mining ore region of world contributes ¼ of
world ore. 4 major regions of mining.
– 1) Ukraine
• Krivoi Rog is main area of iron mining, mostly haematite, magnetite is
also available. 50km in length and 4km in breadth has enormous
resources of ore whose content is about 50%. This field gives ½ of
total production of CIS. The area enjoys advantages of easy
transportation both water and land, nearness to markets of East
European countries.
• Kerch situated on the eastern tip of Crimean Peninsula contributes 5%
poor quality of limonite with 25-40% ore
– 2) Urals
• Magnotogrsk is most outstanding. Name signifies ‘Magnet mountain’
refers to hill of iron ore over 150metres above the surface mainly
magnetite ore. Supplies 1/3 of the total ore of CIS. Other areas are
Kustanay, Vvoskava, Baikal and Chelyabinsk.
– 3) Kursk
– 4) Kuznetsk
– Also available in Siberia (Kuznetsk and Angara), Kursk, Tula,
Lipetsk (near Moscow) and Karelia (near Volgograd)
• USA-nearly 50MT in 2010. There are 22 states in USA.
Main region are
– Lake Superior
• Mesabi, Vermillion, Cuyana, Marquette, Minominee, Gogebic
ranges. Nearly 80% of US ore is obtained. Mesabi range is by far
the most outstanding. Lies in the Minnesota state nearly 100km
from the shore of Lake Superior. Many geographical and
economical factors favourable for large scale mining of iron ore in
this region.
– Alabama Region
• 5-10% of US ore production. Ore mined in Red mountains and
Birmingham valley. Ore field lie to the southern end of Appalachian
mountains where haemetite & magnetite of good quality. Mining
activity continues throughout year on account of cool winters. Ore
locally used in States of Alabama, Tennessee & Georgia.
– Others
• North East Iron ore fields-Adirondacks field (New York) & Cornwal
field (Pennsylvania) magnetite ore. Smelting is done nearby. Mining
is also done in state of Newjersy.
• Western ore field-Utah, Nevada, Wyoming, Montana & California
15% of US ore. Despite huge production imports from Chile,
Sweden, Spain & Algeria in order to meet the demand of steel
industry.
• Canada – 3 region. They are Lake
Superior region
– Ontario
• Ontario province deposits occur at Steep Rock
Lake & Miohipicoten.
– Quebec
• Labrador lowlands poor quality
– New Foundland
• Belie Island medium grade haematite ore
– Production is consumed in St Lawrence
lowland industrial centres & the remaining is
exported to USA, Japan, UK and other
European countries.
Europe-Sweden, France, Germany, the UK and Spain
•
Sweden
–
•
France
–
•
Poor content 27%. Mines are deep, exploitation difficult and expensive. Areas are –
Volgelburg, Sudetanland, Silesia, West Phalia, Saxony and Salzgilter region, south east of
Hanover. German steel industry depends upon imports from France, Sweden and Algeria.
Spain
–
•
Fields are in Lorraine-low content 40-45% but contains high phosphoric content. Ore seams
are nearly 100feet in thickness and are at depth of 600 feet. Area are- Briey, Longwy & Metz.
Thronville are leading mining centre.
Germany
–
•
leading producer in Europe. Deposits of high grade, reserves are enormous. Ores lies close
to surface. Easy & cheap to mine by open cast methods. The Northern mines of Kiruna &
Gallivare face severe winters & short hours of day light in winters and as such output is
restricted. Ores transshipped via Gulf of Bothania in summer and Narvik (Norway) in winter
when the Gulf is frozen. Also mined in Central Sweden at Dannesmora & Grangeborg. In
southern Sweden, Kopparberg-mines are deep, high grade , demand is negligible. Enough
ore for export- exported to USA, Germany, the UK & other European countries.
Large deposits in the NW part of the country near Bilbao on the Bay of Biscay. Iron content
over 50%. Ore free from sulphur and phosphorus. Cantabrian region produce most of output.
Ore is major export item, send to adjoining European countries.
UK
–
Cleveland, Midland and Scottish fields. Production is insufficient, import from Sweden,
France, Africa and Venezuela.
• The countries of continent of Africa accounts 10% of world output of
iron ore.
– N African countries are major contributors-Algeria, Morocco, Tunesia,
Liberia and Muritania.
– W African countries-Sierra Leone and Guinea.
– Union of S Africa is minor producer. Most production is exported due to
steel manufacturing is not developed in African countries except S
Africa.
• China
– Large ore deposits-Manchurian deposits at Anshan. Other region arelower Yangtze at Tayeh, the Chung King area and around Taiyun.
Scattered deposits occur in the Shantung peninsula, north of Paotow in
inner Mongolia, at Kinchuan and on the erstwhile USSR border in
Sikiang in lower Sikiang, near Canton and on island of Haisan in south.
• Australia
– Large ore reserves, widely distributed in western Australia at Mt
Goldsworthy, Mt whaleback, Mt Bruce, Mt Tom Price and at Yampi
Sound. Ore also obtained from Iron Knob in S Australia.
• India
– Reserves at tune of 12000MT both haematite and magnetite. Mined
nearly 83MT in 2002. areas are- Orissa, Bihar, Jharkhand, MP, AP, T
Nadu, UP, Rajasthan.