Indirect reduction of steel - Revision history

Multivac at 09:44, 23 July 2020

2020-07-23T09:44:50Z

Jburk at 21:17, 17 December 2018

2018-12-17T21:17:50Z

ChristiaanK: Internal links

2013-02-17T11:36:32Z

Internal links

ChristiaanK: Added older method

2013-02-17T11:24:19Z

Added older method

ChristiaanK: Created page

2013-02-04T12:35:55Z

Created page

New page

'''Indirect reduction''' is the production of [[steel]] from [[iron ore]] in two steps: first adding carbon, then removing carbon.

Note: Numerous details have been left out for the sake of clarity. The information below is not sufficient for the production of high-quality metal.

==Process overview==
Pig iron (which is high-carbon iron similar to [[cast iron]], but not intended as a final product) is produced in a blast furnace and then has excess carbon removed in an oxygen furnace.

Oxygen is blown into the molten pig iron at supersonic speeds, where it burns with carbon (a stronger reducing agent than iron) to produce carbon dioxide gas (which escapes) and heat. The reaction is highly energetic and serves to agitate the molten metal (mixing it) and also heats it (molten pig iron comes out of the blast furnace at less then the melting point of steel). The Bessemer converter, the original 19th century oxygen furnace, had a lining of acidic materials. The modern furnace is known as the basic oxygen furnace, due to its basic lining.

After the composition is further fine-tuned, the steel can be cast into various shapes.

==Comparison with direct reduction==
*Advantages
**Simpler, provided that large quantities of carbon and oxygen are available.
**Requires less electricity (when compared to melting directly reduced iron with an electric arc furnace).
**There is a reduced risk of [[hydrogen fracturing]] when compared to direct reduction by hydrogen gas.
*Disadvantages
**Uses more energy overall.
**Using hydrogen gas as the main reducing agent inherently implies direct reduction.

[[Category:Industry]]

← Older revision		Revision as of 09:44, 23 July 2020
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	The wrought iron for this process would itself have been converted from pig iron (see [[wrought iron]] for details), making it a three-step process of adding carbon, removing carbon and then adding carbon again.		The wrought iron for this process would itself have been converted from pig iron (see [[wrought iron]] for details), making it a three-step process of adding carbon, removing carbon and then adding carbon again.
		+
		+	==Direct reduction cycle==
		+	Iron can also be reduced via direct reduction by syngas (CO + H<sub>2</sub>) at high temperature (~1200K) , producing Fe, CO<sub>2</sub> and H<sub>2</sub>O<ref>https://www.researchgate.net/profile/Dabin_Guo/publication/309722185_fuel_process_techology/links/581eff1208ae40da2caf27fa.pdf</ref>. That CO<sub>2</sub> and H<sub>2</sub>O can then be recycled via a Zinc Sulfur Iodine reactor<ref>https://doi.org/10.1016/j.apenergy.2013.03.019</ref> to regenerate the syngas, as well as a useful O<sub>2</sub> stream. This [https://en.wikipedia.org/wiki/Direct_reduced_iron direct reduction iron] can then be processed into steel, or other iron products in a secondary process.

	==Comparison with direct reduction==		==Comparison with direct reduction==

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	<references />		<references />

−	[[Category:~~Industry]]~~	+	[[Category:Mining and Refining]]
−	~~[[Category:Metallurgy~~]]

@@ Line 6: / Line 6: @@
 '''Pig iron''' (which is high-carbon iron similar to [[cast iron]], but not intended as a final product) is produced in a blast furnace and then has excess carbon removed in an oxygen furnace.
-Oxygen is blown into the molten pig iron at supersonic speeds, where it burns with carbon (a stronger reducing agent than iron) to produce [[carbon dioxide]] gas (which escapes) and heat. The reaction is highly energetic and serves to agitate the molten metal (mixing it) and also heats it (molten pig iron comes out of the blast furnace at less then the melting point of steel). The '''Bessemer converter''', the original 19th century oxygen furnace, had a lining of acidic materials. The modern furnace is known as the '''basic oxygen furnace''', due to its basic lining.
+[[Oxygen]] is blown into the molten pig iron at supersonic speeds, where it burns with [[carbon]] (a stronger reducing agent than iron) to produce [[carbon dioxide]] gas (which escapes) and heat. The reaction is highly energetic and serves to agitate the molten metal (mixing it) and also heats it (molten pig iron comes out of the blast furnace at less then the melting point of steel). The '''Bessemer converter''', the original 19th century oxygen furnace, had a lining of acidic materials. The modern furnace is known as the '''basic oxygen furnace''', due to its basic lining. This process lowers the carbon content of the metal to the desired value.
 After the composition is further fine-tuned, the steel can be cast into various shapes.
@@ Line 18: / Line 18: @@
 *Advantages
 **Simpler, provided that large quantities of carbon and oxygen are available.
-**Requires less electricity (when compared to melting directly reduced iron with an electric arc furnace).
+**Requires less instantaneous [[electric power]] (when compared to melting [[direct reduction of steel | directly reduced iron]] with an [[electric arc furnace]]).
-**There is a reduced risk of [[hydrogen fracturing]] when compared to direct reduction by hydrogen gas.
+**There is a reduced risk of [[hydrogen fracturing]] when compared to direct reduction by [[hydrogen]] gas.
 *Disadvantages
 **Uses more energy overall.

@@ Line 4: / Line 4: @@
 ==Process overview==
-Pig iron (which is high-carbon iron similar to [[cast iron]], but not intended as a final product) is produced in a blast furnace and then has excess carbon removed in an oxygen furnace.
+'''Pig iron''' (which is high-carbon iron similar to [[cast iron]], but not intended as a final product) is produced in a blast furnace and then has excess carbon removed in an oxygen furnace.
-Oxygen is blown into the molten pig iron at supersonic speeds, where it burns with carbon (a stronger reducing agent than iron) to produce carbon dioxide gas (which escapes) and heat. The reaction is highly energetic and serves to agitate the molten metal (mixing it) and also heats it (molten pig iron comes out of the blast furnace at less then the melting point of steel). The Bessemer converter, the original 19th century oxygen furnace, had a lining of acidic materials. The modern furnace is known as the basic oxygen furnace, due to its basic lining.
+Oxygen is blown into the molten pig iron at supersonic speeds, where it burns with carbon (a stronger reducing agent than iron) to produce [[carbon dioxide]] gas (which escapes) and heat. The reaction is highly energetic and serves to agitate the molten metal (mixing it) and also heats it (molten pig iron comes out of the blast furnace at less then the melting point of steel). The '''Bessemer converter''', the original 19th century oxygen furnace, had a lining of acidic materials. The modern furnace is known as the '''basic oxygen furnace''', due to its basic lining.
 After the composition is further fine-tuned, the steel can be cast into various shapes.
 ==Comparison with direct reduction==
@@ Line 18: / Line 23: @@
 **Uses more energy overall.
 **Using hydrogen gas as the main reducing agent inherently implies direct reduction.
 [[Category:Industry]]