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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 ]
The Boudouard reaction is an important process inside a blast furnace. The reduction of iron oxides is not achieved by carbon directly, as reactions between solids are typically very slow, but by carbon monoxide. The resulting carbon dioxide undergoes a (reverse) Boudouard reaction upon contact with coke carbon.
The internal operating temperature of the water jacket furnace is lower than that of a blast furnace used to make iron, and the process does not depend upon the formation of a bosh shell, as is critical in the operation of a blast furnace making iron. Conventional blast furnaces used for smelting iron ore use a hot blast.
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 efficiency of the blast furnace was improved by the change to hot blast, patented by James Beaumont Neilson in Scotland in 1828. [90] This further reduced production costs. Within a few decades, the practice was to have a 'stove' as large as the furnace next to it into which the waste gas (containing CO) from the furnace was directed and burnt.
The blast furnace is similar in structure to a cupola furnace used in iron foundries. The furnace is charged with slag, scrap iron, limestone, coke, oxides, dross, and reverberatory slag. The coke is used to melt and reduce the lead. Limestone reacts with impurities and floats to the top. This process also keeps the lead from oxidizing. The ...
The lower the position of a metal's line in the Ellingham diagram, the greater is the stability of its oxide. For example, the line for Al (oxidation of aluminium) is found to be below that for Fe (formation of Fe 2 O 3) meaning that aluminium oxide is more stable than iron(III) oxide. Stability of metallic oxides decreases with increase in ...