Iron ore, production

Other countries that have large iron ore deposits include Brazil (Carajas and Quaddlatero Ferrifero deposits), AustraUa (Pilbara deposits), Ukraine (Krivi Rog deposit), Russia (Kursk deposit), Venezuela (Cerro BoHvar deposit), India (Bihar-Orissa, Hospet, Kudremukh, and Goa deposits). South Africa (Sishen and Thabazimbi deposits), and Sweden (Kimna, Svappavaara, and Malmberget deposits). A Hst of world iron ore production and reserves in 1992 by country is shown in Table 3. 

Annual world iron ore production has hovered around 9 to 9.75 x 10 t since the mid-1980s. International trade of iron ore peaked in 1980 at 4.24 X 10 t otherwise it has remained fairly steady in the range of3.6to4x 10 t/yr per year since the mid-1980s. The main exporting countries are Brazil, AustraUa, India, Canada, South Africa, Russia, Ukraine, and Venezuela. 

Fig. 1. World production trends in steelmaking raw materials where (—) represents iron ore production ( ...

Iron ore production for the iron and steel industry accounts for more than 99% of the total iron mined. At present, the largest iron ore mine in the world is Mount Whaleback in the Pilbara district of Western Australia. Most of the ore there is in the form of banded iron formations (BIF) and consists of hematite and goethite. 

FeOOH) and, in some places, siderite (FeCOj) are the most common varieties. World iron ore production is about 870 x 10 tons (approximately 29% in the former Soviet Union, 15% in Brasilia, 11% each in China and Australia, and 10% in North America). Deposits in emiched weathering zones are preferentially exploited. The ores are crushed and concentrated to have an iron content of 60% by milling and sintering before shipment to the ironworks (which are frequently overseas). This pro-... 

Annual iron ore production figures for the year 2000 are shown in Table 8.5. 

Gobalt occurs in the minerals cobaltite, smaltite, and erythrite, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product. It is also present in meteorites. 

Direct Reduction. Direct reduction processes are distinguished from other ironmaking processes in that iron oxide is converted to metallic iron without melting. Because this product, called direct reduced iron (DRI), is soHd, it is most suitable for melting in an electric arc furnace (EAF) as a substitute for scrap (see Furnaces, electric). The briquetted form of DRI, hot briquetted iron (HBI) is used when the product is to be transported. Briquetting increases density and chemical stabiUty. The predominant direct reduction processes (MIDREX and HyL III) are based on natural gas as a fuel and reductant source. They are economically attractive in regions where natural gas is cheap and abundant, especially if iron ore is available nearby (see Iron BY DIRECT reduction). ... 

Direct reduction (DR) is the process of converting iron ore (iron oxide) into metallic iron without melting. The metallic iron product, known as direct reduced iron (DRI), is used as a high quaUty feed material in steelmaking. 

SL/RN Process. In the SL/RN process (Fig. 4), sized iron ore, coal, and dolomite are fed to the rotary kiln wherein the coal is gasified and the iron ore is reduced. The endothermic heat of reduction and the sensible energy that is required to heat the reactants is provided by combustion of volatiles and carbon monoxide leaving the bed with air introduced into the free space above the bed. The temperature profile in the kiln is controlled by radial air ports in the preheat zone and axial air ports in the reduction zone. Part of the coal is injected through the centerline of the kiln at the discharge end. The hot reduced iron and char is discharged into an indirect rotary dmm cooler. The cooled product is screened and magnetically separated to remove char and ash. 

Charcoal was an important industrial raw material in the United States for iron ore reduction until it was replaced by coal in the early 1880s. Charcoal production increased, however, because of the demand for the by-products acetic acid, methanol, and acetone. In 1920, nearly 100 by-product recovery plants were in operation in the United States, but the last plant ceased operation in 1969. 

Bastnasite has been identified in various locations on several continents. The largest recognized deposit occurs mixed with monazite and iron ores in a complex mineralization at Baiyunebo in Inner MongoHa, China. The mineral is obtained as a by-product of the iron ore mining. The other commercially viable bastnasite source is the Mountain Pass, California deposit where the average Ln oxide content of the ore is ca 9%. This U.S. deposit is the only resource in the world that is minded solely for its content of cerium and other lanthanides. 

Russia and the RepubHc of South Africa account for more than half the world s chromite ore production. Almost all of the world s known reserves of chromium are located in the southeastern region of the continent of Africa. South Africa has 84% and Zimbabwe 11% of these reserves. The United States is completely dependent on imports for all of its chromium (4). The chromite s constitution varies with the source of the ore, and this variance can be important to processing. Typical ores are from 20 to 26 wt % Cr, from 10 to 25 wt % Fe, from 5 to 15 wt % Mg, from 2 to 10 wt % Al, and between 0.5 and 5 wt % Si Other elements that may be present are Mn, Ca, Ti, Ni, and V. AH of these elements are normally reported as oxides iron is present as both Fe(II) andFe(III) (5,6). 

The solid iron ore is formed into pellets, which are presented to the gas in a vertical shaft containing the pellets in tire form of a packed bed. The reducing gas enters the shaft at the bottom and rises tluough the packed bed reacting to form gaseous oxidation products, CO2 and H2O. The heat required to raise the reactants to a temperature at which the reaction rate is fast enough is usually canied by the inlet gas phase. 

The Japanese Direct Iron Ore Smelting (DIOS) process. This process produces molten iron directly with coal and sinter feed ore. A 500 ton per day pilot plant was started up in October, 1993 and the designed production rates were attained as a short term average. Data generated is being used to determine economic feasibility on a commercial scale. 

By far the largest source of phosphorus is phosphate rock, with some use of phosphatic iron ore, from which phosphorus is obtained as a by-product from the slag. Phosphate rock consists of the insoluble tricalcium phosphate and other materials. For use as a fertilizer, phosphate must be converted to the water soluble form, phosphoric acid (H3PO4) which has three hydrogen atoms, all of which are replaceable by a metal. Tricalcium phosphate, is converted to soluble monocalcium phosphate and to superphosphate, A fertilizer factory, typically, a large installation, characterized by large silos produces year round, but peaks with the demands of the growing season. Phosphorus has many uses other than for fertilizer. 

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