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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.
Initially, sulfur accelerates the extraction of oxygen from the iron oxide, but this effect reverses once metallic iron begins to form, significantly slowing the oxygen extraction process. [3] This unusual behavior is attributed to sulfur's strong affinity for the metallic iron that forms on the pellet surface, which inhibits the penetration of ...
Blast furnaces are currently rarely used in copper smelting, but modern lead smelting blast furnaces are much shorter than iron blast furnaces and are rectangular in shape. [76] Modern lead blast furnaces are constructed using water-cooled steel or copper jackets for the walls, and have no refractory linings in the side walls. [77]
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 ...
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 HIsarna ironmaking process is a direct reduced iron process for iron making in which iron ore is processed almost directly into liquid iron ().The process combines two process units, the Cyclone Converter Furnace (CCF) for ore melting and pre-reduction and a Smelting Reduction Vessel (SRV) where the final reduction stage to liquid iron takes place.
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. [ 63 ] [ 64 ] Conversely, many direct-reduction processes are disadvantaged by the costly transformation of ore into pellets: these cost on average 70% more than raw ore. [ 65 ]
The Chinese are thought to have skipped the bloomery process completely, starting with the blast furnace and the finery forge to produce wrought iron; by the fifth century BC, metalworkers in the southern state of Wu had invented the blast furnace and the means to both cast iron and to decarburize the carbon-rich pig iron produced in a blast ...