Saturday, October 7, 2017

Iron and Steel Industry

Iron and steel industry is made up of hundreds of large and small businesses, some of which are basic steel producers whereas others from into finished products.


Iron is one of the most widely distributed and abundant elements in the Earth’s crust, constituting about 5 % of the total. It is estimated that world supplies of iron ore are adequate for at least 100 years in spite of a projected increased in production that could double during the next quarter of a century.

Iron Ore

The development of present iron-ore deposits began millions of years ago when most of the world was under water. Immense quantities of sediment, some rich in iron, settled out through the ages. These age-old, iron bearing marine sediments from the basis of the major usable iron deposits in the world today. After these deposits were incorporated into the crust f the Earth, they were gradually moved closer to the surface by the drift of the continents and the upheaval of sediment layers on th sea bottoms. There are two color type of iron ore pure black and brown black. For black iron ore contain magnetic iron, and for brown and black color ore usually contain copper ore inside.

contain magnetic ore
Black iron ore

contain other substance usually copper
Brown and Black iron Ore

Iron ore reserves are found worldwide. Areas with more than 1 billions metric tons of reserves include, in order of decreasing amounts, Australia, Brazil, Canada, United States, Venezuela, South Africa, India, the USSR, Gabon, France, Spain, Sweden and Algeria.

North America has been fortunate in its ore deposits, which are found in commercially usable quantities in 22 states in the United States and in 6 Canadian provinces. In the United States the most abundant supplies, discovered in the early 1890s, are located in the lake superior region around the Mesabi Range. These deposits seemed inexhaustible in the 1930s. The tremendous demand for iron ore during World War II virtually tripled the output of the Mesabi Range and severely depleted its deposits of high grade ore. A worldwide search for new deposits by US companies yielded large deposits of rich ore, acceptable for blast furnace use. In Brazil, Australia, Canada, Venezuela, West Africa, and South Africa. You can see on the mountain if the rock on the mountain look like below picture that mean on the mountain probable contain of iron or copper, and can be mined.

iron rock

iron rock mountain

Two new upgrading techniques that have been developed ore sintering and pelletizing. Sintering is used when ore is two fine to be charge directly into the furnace. The ore is agglomerated with a mixture of coal and coke breeze (a powder) so that it forms a clinker-like substance. Sintering permits the passage difficult. Pelletizing is used to increase the iron content of low-grade ores such as taconites and jaspers, which average from 20% to 30% iron in their natural form, after being crushed, screened, ground, and concentrated, the ore is formed into small pellets with an iron content of 60% or more.

The method are employed in mining iron ore. Underground mining is the least economical and may take place at depths well in excess made in the postwar period, involve reserves that are located close to the surface, the most widely used method of mining today is open-pit mining.

Location of mining

mountain iron rock
iron mining rock

location of iron mining
iron mining location

Iron Making

Iron is made by refining iron ore to a point where it reaches 90% to 95% purity. Refining has been achieved in a number of ways through the centuries, dating back as far as the 2d millennium BC.
Iron production was at first extremely limited because of the slow and difficult methods used to refine ore. At fist lumps of iron were heated in contact with charcoal, producing a pasty mass mixed with a great deal of slag. This was hammered into a semi finished bar and then further worked into finished products.

The content method of smelting iron is in the Blast Furnace, which was developed in a crude form during the Midle ages. The furnace was a stone structure built in the form of a truncated pyramid into which iron ore, charcoal, and a fluxing material, usually limestone, were charged. Combustion was aided by a blast of cold air blown in at the base of the furnace. This operation chaged little anywhere in the world until about 1840, when anthracite coal was used for fuel in place of charcoal, and the air blast was heated.

The construction of furnace already changed at about that time. The short, square based stone stack was replaced by a tall, cylindrical structure made of wrought iron plates and lined with firebrick. These furnace were larger and increased the production of iron considerably. In the 1870s and 80s anthracite was gradually replaced by coke made from bituminous coal. Furnaces grew larger and by 1900 were capable of producing more than 200 tons of molten pig iron per day.

The blast-furnace process operates 24 hours a day, 7 days a week. This continuity is essential to efficient operation, if furnace is shut down, several days are often required before smooth operation is restored. The raw materials are constantly being charged into the top to replace the gassified carbon and the molten products that are removed from the furnace. The furnace is tapped about four times every day, at intervals of five or six hours.

The use of Iron

Until 1870 the greatest use of iron was in railroad rails and railroad car wheels. Iron was used in construction (steel structure) to a limited extent. Iron also had significant uses in the form of nails and wire, and in sheets steel or plated with tin, called tinplate, which were used for food containers.

With the advent of steel, most of the iron came to be used as raw material for the production of steel, and that remain its primary use. Steel derivative like carbon steel, alloyed steel, stainless steel and many others.

To day the principal use of blast furnace iron that is nor turned into steel is for cast product. The iron is purchased by foundries in solid form and then melted together with scrap to make castings for a number of industries.

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