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Blast furnaces differ from bloomeries and reverberatory furnaces in that in a blast furnace, flue gas is in direct contact with the ore and iron, allowing carbon monoxide to diffuse into the ore and reduce the iron oxide. The blast furnace operates as a countercurrent exchange process whereas a bloomery does not.
The PCI method is based on the simple concept of primary air (termed the "conveying gas") carrying pulverized coal which injected through a lance to the tuyere (mid-bottom inlet of a blast furnace), then mixed with secondary hot air (termed the "blast") supplied through a blowpipe in the tuyere and then piped to a furnace to create a balloon ...
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 ...
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.
A part of the smaller one ( 5 – 20 mm) is used for hearth layer in sinter machine and the rest is taken to the blast furnace along with the biggest sized sinters. The temperature is typically maintained between 1,150 and 1,250 °C (2,100 and 2,280 °F) in the ignition zone and between 900 and 1000 °C in the soaking zone to prevent sudden ...
Molten pig iron (sometimes referred to as "hot metal") from a blast furnace is poured into a large refractory-lined container called a ladle. The metal in the ladle is sent directly for basic oxygen steelmaking or to a pretreatment stage where sulfur, silicon, and phosphorus are removed before charging the hot metal into the converter.
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 furnace is then tilted forward so that the lance is above the charge, and the charge is melted using an oil or natural gas burner that is inserted near the top of the furnace. [6] Once the charge has been melted, the furnace is tilted back into the blowing position and oxygen is blown into the bath. [6]