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Blast furnaces used in the ISP have a more intense operation than standard lead blast furnaces, with higher air blast rates per m 2 of hearth area and a higher coke consumption. [79] Zinc production with the ISP is more expensive than with electrolytic zinc plants, so several smelters operating this technology have closed in recent years. [80]
For blast furnaces, direct reduction corresponds to the reduction of oxides by the carbon in the coke. However, in practice, direct reduction only plays a significant role in the final stage of iron reduction in a blast furnace, by helping to reduce wustite (FeO) to iron. In this case, the chemical reaction can be trivially described as follows ...
Blast furnace gas (BFG) [1] is a by-product of blast furnaces that is generated when the iron ore is reduced with coke to metallic iron. It has a very low heating value , about 3.5 MJ/m 3 (93 BTU /cu.ft), [ 2 ] because it consists of about 51 vol% nitrogen and 22 vol% carbon dioxide , which are not flammable.
The coking plant that feeds a battery of blast furnaces is just as expensive as the blast furnace and requires a specific quality of coal. [ 64 ] [ 65 ] Conversely, many direct-reduction processes are disadvantaged by the costly transformation of ore into pellets: these cost on average 70% more than raw ore. [ 66 ]
Direct reduction processes can be divided roughly into two categories: gas-based and coal-based. In both cases, the objective of the process is to remove the oxygen contained in various forms of iron ore (sized ore, concentrates, pellets, mill scale, furnace dust, etc.) in order to convert the ore to metallic iron, without melting it (below 1,200 °C (2,190 °F)).
The blast furnace method is expected to survive into the 22nd century because of its efficient rate of iron production at competitive costs compared with other iron-making methods. Blast furnaces keep on improving with adaptations arising from new technologies driven by rising global demand, yet the main chemical process remains the same. But ...
News broke Wednesday that United States Steel plans to sell its two blast furnaces at Granite City Works to SunCoke Energy, Inc. If the sale goes through, it could cost the region approximately ...
The movement away from charcoal in US iron smelting began in 1827, when a puddling furnace in Phoenixville, Pennsylvania started using anthracite coal. Blast furnaces continued to use only charcoal until about 1840, when coke from coal started replacing charcoal as the fuel and reducing agent. [5]