Direct reduction of iron

Direct Reduction of Iron Ore Bibliographical Survey, The Metals Society, London, 1979. 

Other markets for char include iron, steel, and sili-con/ferro-silicon industries. Char can be used as a reducing agent in direct reduction of iron. Ferro-silicon and metallurgical-grade silicon metal are produced carbothermally in electric furnaces. Silica is mixed with coke, either iron ore or scrap steel (in the case of ferro-silicon), and sawdust or charcoal in order to form a charge. The charge is then processed by the furnace to create the desired product. Char can be substituted for the coke as a source of reducing carbon for this process. Some plants in Norway are known to have used coal-char in the production of silicon-based metal products as late as mid-1990.5 The use of char in this industry is not practiced due to lack of char supply. 

Since hydrogen burns cleanly and reacts completely with oxygen to produce water vapor, this makes it more desirable than fossil fuels for essentially all industrial processes. For example, the direct reduction of iron or copper ores could be done with hydrogen rather than smelting by coal or oil in a blast furnace. Hydrogen can be used with conventional vented burners as well as unvented burners. This would allow utilization of almost all of the 30 to 40% of the combustion energy of conventional burners that is lost as vented heat and combustion by-products. 

SL/RN process -urea-formaldehyde [FORMALDEITYDE] (Vol 11) -direct reduction of iron [IRON BY DIRECT REDUCTION] (Vol 14)... 

Conventional uses of methanol account for 90% of present consumption and include formaldehyde, dimethyl terephthalate, methyl methacrylate, methyl halides, methylamines and various solvent and other applications. Newer uses for methanol that have revitalized its growth and outlook include a new technology for acetic acid, single cell protein, methyl tertiary butyl ether-(MTBE), and water denitrification. Potential uses for methanol include its use as a carrier for coal in pipelines, as a source of hydrogen or synthesis gas used in direct reduction of iron ore, as a direct additive to or a feedstock for gasoline, peak power shaving and other fuel related possibilities. Table II lists the world methanol demand by end use in 1979. 

Fuel uses are a potential application which would require substantial volumes of methanol. As mentioned earlier they are reviewed in the following chapter. A fuel related potential use of methanol is as a replacement for water used to carry coal in pipelines. Methanol is being considered for this use because it would eliminate a demand for water, which is often scarce in areas where coal is mined, and methanol could be burned as a fuel with the coal at its destination. Methanol has also been touted as a good feedstock for gases used in the direct reduction of iron ore. If this use of methanol is realized, it will not be before the mid to late 1980 s. Other potential new uses for methanol include a feedstock for ethylene and propylene production (9) and a feedstock for gasoline production (10). 

Direct Reduction of Iron Ore in a Moving-Bed Reactor Analyzed by Using the Water Gas Shift Reaction... 

A model for the direct reduction of iron ore in a moving bed has been developed. The model accounts for the water gas shift equilibrium as well as reduction by the species H2 and CO. Inclusion of this equilibrium has been shown to enhance reduction especially at the high conversions required.Increase of operating temperature can give decreased conversions. 

Another approach receiving increased interest is direct reduction of iron ore. In this process, coal is added directly to the smelting vessel and is the source of the reducing gases and thermal energy. Thus, easily crushed and handled, inexpensive noncoking coals of high calorific value can be used. Particle size requirements are variable, but less than 1 mm is most often used and, in some cases, there is an effort to restrict moisture content to below 6 percent. 

SPARG A process for the C02 reforming of methane, producing carbon monoxide and hydrogen, using a partially presulfided nickel catalyst. Developed by Haldor Topsoe in the 1990s for the direct reduction of iron ore, but not commercialized. 

The most likely syngas consumers in the infrastructure are Fisher-Tropsch diesel processes, ammonia producers, methanol producers and the Direct Reduction of Iron (DRI) process. The H2/CO ratios required by these process range from >0.68. 4. Assuming that syngas is produced using entrained flow reactors with reformers, preliminary economic evaluation revealed that the HQ pipeline should provide syngas in a ratio bandwidth of 0.9-1.1. 

While the traditional blast furnace is preferred for large-scale operations, processes for the direct reduction of iron ore using carbon monoxide and/or hydrogen are becoming increasingly important. Such processes have the ability to use lower-grade iron ores, particularly fine ore particles, and fuels such as natural gas that are unacceptable for the blast furnace. The iron... 

The M3A1 based materials were exposed in flowing C0-H2-H20 mixtures at 650 °C for different periods of time. Corresponding atmospheres are used in many processes attained from methane conversion for use in synthesis of ammonia, hydrocarbons, alcohols etc. or in the direct reduction of iron ores. The materials tested were (concentration in wt%) ... 

W. Pietsch, Die KomvergroKerung in der Verfahrenstechnik imd ihre industrielle Anwen-dung am Beispiel der Direktreduktion von Eisenerzen. (Size enlargement in process engineering and its industrial application as exemplified by the direct reduction of iron ores.) Aufbereitungs-Technik (part 1) 23 (1982)4, 193-200 (part 2) 23 (1982)5, 248-257. 

Another new application of coal briquetting that is already being used, is the den-sification and shaping of solid reductant for the direct reduction of iron ores. Such briquettes are mixed with iron ore and fed into the reactor where controlled combustion provides heat and reducing gas for the production of direct reduced iron (DRI). 

Size enlargement in process engineering and its industrial application as exemplified by the direct reduction of iron ores.)... 

Direct reduction of iron ore to sponge iron which can then be converted to steel in an electric arc furnace is a process that takes place outside a blast furnace avoiding the use of coke. This process is more favorable than the traditional raw iron production by merms of coke. The chemical reactions are ... 

As an indication of the flexibility of the EAF, it is used in some developing countries for the direct reduction of iron ore by carbon [27.18]. The furnace is charged with iron ore intimately mixed with ground carbon. Quicklime, calcined dolomite and fluorspar are added and an oxygen lance is used to oxidise the impurities much as in the BOS process. The slag is removed and the chemical... 

Midrex process Process for the direct reduction of iron ore with reduction gases [5, 6]. 

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