Iron ore smelting

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. 

Some cokeless technologies in use or under development include the Japanese direct iron ore smelting (DIOS) process, in which molten iron is produced directly with coal and sinter feed ore, the HIsmelt process, where ore fines and coal are used to achieve a production rate of 8 t/h using ore directly in the smelter, and the Corex process, which has an integral coal desulfurizing step, making it amenable to a variety of coal types.14... 

Inatani, T., The Current Status of JISF Research on the Direct Iron Ore Smelting Reduction Process (DIOS Project), in AIME Ironmaking Conf. Proc., p. 651 (1991)... 

In iron ore smelting spherical pellets of iron oxide (taconite) are reacted with CO (from coke) in a blast furnace... 

Iron ore smelting with coke (Abraham Darby) Darby develops a method of smelting iron ore by using coke, rather than charcoal, which at the time was becoming scarce. Coke is made by heating coal and driving off the volatiles (which can be captured and used). 

Fukui K (1996) A study on the new iron ore smelting reduction processes. Tetsu-to-Hagane 82(1) 1-7... 

The process of extraction requires first smelting (to obtain the crude metal) and then refining. In smelting, iron ore (usually an oxide) is mixed with coke and limestone and heated, and hot air (often enriched with oxygen) is blown in from beneath (in a blast furnace). At the lower, hotter part of the furnace, carbon monoxide is produced and this is the essential reducing agent. The reduction reactions occurring may be represented for simplicity as ... 

Smelting iron ores produces large amounts of sulfur dioxide, which is catalytically oxidized to sulfur trioxide for sulfuric acid production. This process is declining due to pollution control measures and the presence of some impurities in the product acid. 

The largest releases of polycyclic aromatic hydrocarbons (PAHs) are due to the incomplete combustion of organic compounds during the course of industrial processes and other human activities. Important sources include the combustion of coal, crude oil, and natural gas for both industrial and domestic purposes, the use of such materials in industrial processes (e.g., the smelting of iron ore), the operation of the internal combustion engine, and the combustion of refuse (see Environmental Health Criteria 202, 1998). The release of crude oil into the sea by the offshore oil industry and the wreckage of oil tankers are important sources of PAH in certain areas. Forest hres, which may or may not be the consequence of human activity, are a signihcant... 

Roasting pyrite, an iron ore composed of iron sulfide, results in the oxidation and decomposition of this compound to volatile sulfur dioxide and the formation of iron oxide, which can be smelted with relative ease into iron ... 

Iron ores are comparatively easy to smelt into metal. 

Iron does not occur in nature as a native metal. Lumps of meteoritic iron, which fell to the surface of the earth from outer space, are often found, however. It has been argued whether the earliest iron used by humans was of meteoritic origin or smelted from ores (Piaskowsky 1988). Combined with other elements, iron occurs in a varied range of ferruginous (iron-containing) ores that are widely dispersed on the upper crust of the earth some common iron ores often used for smelting are listed in Table 37. 

The extraction of the common metals from their ores in antiquity was based mainly on relatively simple equipment and processes. Lumps of copper or iron ore, for example, that may have formed part of a ring of stones around an ancient domestic fire and become embedded in its embers, could have been reduced to metal. It is quite reasonable to conjecture, therefore, that some prehistoric campfire became, quite accidentally, the first metallurgical furnace. All that is needed to convert a campfire into a smelting furnace is a small depression in the ground to receive the molten metal. A furnace of this type is illustrated in Figure 42 (Gowland 1912 Killick 2001). 

The authors would like to express their appreciation to researchers at BHP in Australia for providing information on the recent developments in smelting reduction of iron ore. 

Ibaraki, T., Kanemoto, M., Ogata, S., Katayama, H., and Ishikawa, H., Development of Smelting Reduction of Iron Ore - An Approach to Commercial Ironmaking, Iron Steelmaker, 17(12) 30 (1990)... 

HIsmelt A direct iron smelting process in which noncoking coal, fine iron ore, and fluxes and gases, are injected into a molten iron bath the carbon monoxide produced is used to prereduce the ore in a fluidized bed. Under development by CRA, Australia, since the early 1980s, joined by Midrex Corporation in 1988. Their joint venture company, Hismelt Corporation, commissioned a pilot plant at Kwinana, near Perth, Australia, in 1993. 

Pedersen A process for extracting aluminum from bauxite, which also yields metallic iron. The ore is first smelted in an electric furnace with limestone, iron ore, and coke at 1,350 to 1,400°C to produce a calcium aluminate slag and metallic iron. Aluminium is leached from the slag by sodium carbonate solution, and alumina is then precipitated from the leachate by carbon dioxide. The process requires cheap electricity and a market for the iron. It was invented by H. Pedersen in 1924 and operated at Hoy anger, Norway, from 1928 until the mid-1960s. British Patent 232,930. 

It is used in the smelting process to free metals from their ores. It is particularly important in the oxygen-converter process in the production of steel from iron ore. 

Centuries after man had started to use iron oxides as colouring agents, he discovered how to smelt them. The first iron was produced between 4000 and 2000 BC. Since then, this product of iron oxides has been used in weapons, utensils, tools, implements and construction. The extensive English iron ore deposits contributed to the lead England acquired in the Industrial Revolution. 

---