Direct Reduced Iron: Difference between revisions

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'''Direct-reduced iron (DRI)''' is a metallic material formed by the reduction (removal of oxygen) of iron oxide (iron ore) at temperatures below the melting point of iron. DRI is produced by the use of a reducing gas (often a mixture of hydrogen and carbon monoxide). The temperatures for this process are significantly lower than those in a blast furnace, and capital requirements are also lower. DRI may have a sponge-like structure, leading to the alternative name "sponge iron". Suitable starting materials are very high-grade iron ores (70% iron content and up) or rusted scrap steel, which is mostly iron. These could not be used in an induction furnace, as the reduction is a chemical reaction while induction only melts the already-reduced iron. One of the global leaders in sponge iron production is India, which has numerous small or medium-sized facilities. DRI is commonly manufactured in a rotary kiln.
{{Category=Materials}}


HDRI ("hot direct reduced iron"): moving the still-hot iron immediately for melting into an electric arc furnace or [[Induction_Furnace]], to save energy.
[[File:Small rotary kiln.jpg|400px|thumb|right|Small rotary kiln, Brazos County TX, 1966 (image from: Cushing Memorial Library and Archives, Texas A&M via CC license)]]


==Product ecology==
=Basics=
[[Induction_Furnace]] -- could use HDRI 
*Often abbreviated as DRI
*'''Direct-reduced iron is a metallic material formed by the reduction (removal of oxygen) of iron oxide (iron ore) at temperatures ''below the melting point'' of iron. DRI is produced by the use of a reducing gas (mostly a mixture of hydrogen and carbon monoxide). The temperatures for this process are significantly lower than those in a blast furnace, and capital requirements are also lower. DRI may have a sponge-like structure, leading to the alternative name "sponge iron".
*Suitable starting materials are very high-grade iron ores (70% iron content and up) or rusted scrap steel, which is mostly iron. These could not yet be used in an [[induction furnace]], as the reduction is a chemical reaction while induction only melts the already-reduced pure metal. India is one of the global leaders in sponge iron production, having numerous small or medium-sized facilities. DRI is commonly manufactured in a rotary kiln.


[[Gasifier]] -- to make the reducing gas: [http://www.openfarmtech.org/index.php/Compressed_Fuel_Gas syngas] is a mixture of H and CO


Biogas -- methane from biogas can be turned into the H/CO mix. Globally, fossil gas (a.k.a. "natural" gas) is the most commonly used fuel for DRI, so biogas is a possible replacement, although it would probably have to be upgraded first.
=Forms of Material Produced=
*Direct Reduced Iron, or Sponge Iron ( '''May want to make a page for this product, and move this page's content to "Direct Reduction (Mettalurgy)" ? ''' )
*HDRI ("hot direct reduced iron"): when the still-hot iron is immediately moved for melting into an electric arc furnace or [[induction furnace]], to save energy. Caution: when HDRI is exposed to air, it may rapidly oxidize (=explode!). '''OSE Will Use This for On-Site Usage'''
*Hot-briquetted iron (HBI) is a form of DRI designed for ease of shipping, handling and storage. It is made via briquetting the iron while it is still hot, then letting it cool
**Mainly used for trade (See [[Iron Shortage]] ) due to it's stability
**Does a [[Pelletized]] version exist/make sense?
**'''OSE Will Use This For Trade and Long Term Storage'''


Waste heat -- This process produces waste heat that could be used for pyrolyzing biomass (pyrolysis = heating in the absence of oxygen). This process releases syngas, keeping the process going, all powered by solid biomass, generating biochar as a by-product (permanently fixed carbon) .
=Product ecology=
==In's==
*Energy, which will be vary depending on if onsite fuel is used, or if electric heating, and offsite reducing gas are used
**[[Electricity]]
**[[Heat]]
*[[Iron Ore]] (deleted bit had some numbers on concentrations grab that + more sources later)
*[[Iron Scrap]] and [[Steel Scrap]]
*[[Reducing Gas]] (Either [[Syngas]] from an onsite source, or [[Hydrogen]] from remote sources)


[[Biochar]] -- is a charcoal-like soil amendment. It is resistant to biodegradation, i.e. it is carbon that has been permanently removed from the atmosphere. Some of the syngas that is produced during pyrolysis could be used for making DRI. If these processes are combined, then biochar is a valuable by-product. The slurry from a biogas digester could be co-composted with biochar to make an excellent soil amendment.
==Out's==
* '''Waste heat''' -- The DRI process generates waste heat that can potentially be used for pyrolyzing further biomass (pyrolysis = heating in absence of oxygen). Pyrolysis releases yet more '''syngas''' which can be fed back into the process. Everything is thus powered by biomass, generating '''[[biochar]]'''. In cold climates, any kind of waste heat can obviously be useful for heating winter greenhouses.


==Further information is needed !==  
=Further information is needed !=
*''Is this actually feasible on the small scale ?''
;Is this actually feasible on the small scale?
*''Are we missing something here ?''
: Sure - thousands of these in India
*''Does the process take place at atmospheric pressure ?''
;Does the process take place at normal atmospheric pressure?
*''Can a rotary kiln be designed at the village scale ?''
: Yes, it can
*''Are sufficient amounts of high-grade ores or rusted steel available ?''
;Can a rotary kiln be designed for the village scale?
: Yes, but this process does not have to take place in rotary kiln; the only thing that matters is good mixing.
A: Scalability is feasible, but efficiency may not be as good. The processes of the largest plants can also be done on a table top. The question is - at what point does it still make sense to do so? If we have access to abundant energy, feasibility may occur at a village scale.
;Are sufficient amounts of high-grade ores or rusted steel available?
: It doesn't matter. If we get the metal extraction from clays working, then we can concentrate most clays into high-grade ores.
: Scalability is feasible, but efficiency may not be as good. The processes of the largest plants can also be done on a table top. The question is - at what point does it still make sense to do so? If we have access to abundant energy, feasibility may occur at a village scale (added: concentrated solar power can serve as heat source; needs methane atmosphere). (Perhaps the [[Charcoal Blast Furnace]] could handle low end, and dri, the high end?)


A: This appears as a good alternative for smaller scale, lower-cost process, worth adding to our general awareness.
This appears to be a good alternative for smaller scale, lower-cost process, worth adding to our general awareness.


[[Category:Steel]]
=Other Metals=
[[Category:Metal Production]]
*paper: [http://openfarmtech.org/w/images/c/c9/Halman.pdf Carbothermal reduction of alumina: Thermochemical equilibrium calculations and experimental investigation]  
*paper: [http://openfarmtech.org/w/images/c/c3/Lvov.pdf Mechanism of carbothermal reduction of iron, cobalt, nickel and copper oxides]  


==External links==  
=Internal Links=
* Wikipedia: [http://en.wikipedia.org/wiki/Direct_reduced_iron Direct Reduced Iron]  
* [[Open Source Direct Reduced Iron Reactor]]
* Wikipedia: [http://en.wikipedia.org/wiki/Sponge_iron_reaction Sponge Iron Reaction]  
* [[Open Source Metal Recycling + Refining Construction Set]]
* Wikipedia: [http://en.wikipedia.org/wiki/Water_gas Water Gas Shift] => a way to increase the hydrogen content in syngas
* [[Magnetite]] - incl. extraction of high-grade iron ore from beach sand
* war-time 1942 TIME Magazine article on [http://www.time.com/time/magazine/article/0,9171,796046,00.html sponge iron]
* [[Metal]]
* [[Metal Refining]]
* [[Steel from dirt]]
* [[Kiln]]
* [[Charcoal Blast Furnace]]
 
=External links=  
* [[Wikipedia: Direct reduced iron]]  
* [[Wikipedia: Sponge iron reaction]]  
* [[Wikipedia: Water gas]] shift -> a way to increase the hydrogen content in syngas
* [http://www.time.com/time/magazine/article/0,9171,796046,00.html WW2-era (1942) TIME Magazine article on sponge iron]
* [https://www.hybritdevelopment.com/ A Company Attempting to Commercialize This]
 
[[Category: Incomplete Pages]] [[Category: Materials]] [[Category:Metalworks]]

Latest revision as of 07:05, 19 December 2020

Main > Materials

Small rotary kiln, Brazos County TX, 1966 (image from: Cushing Memorial Library and Archives, Texas A&M via CC license)

Basics

  • Often abbreviated as DRI
  • Direct-reduced iron is a metallic material formed by the reduction (removal of oxygen) of iron oxide (iron ore) at temperatures below the melting point of iron. DRI is produced by the use of a reducing gas (mostly a mixture of hydrogen and carbon monoxide). The temperatures for this process are significantly lower than those in a blast furnace, and capital requirements are also lower. DRI may have a sponge-like structure, leading to the alternative name "sponge iron".
  • Suitable starting materials are very high-grade iron ores (70% iron content and up) or rusted scrap steel, which is mostly iron. These could not yet be used in an induction furnace, as the reduction is a chemical reaction while induction only melts the already-reduced pure metal. India is one of the global leaders in sponge iron production, having numerous small or medium-sized facilities. DRI is commonly manufactured in a rotary kiln.


Forms of Material Produced

  • Direct Reduced Iron, or Sponge Iron ( May want to make a page for this product, and move this page's content to "Direct Reduction (Mettalurgy)" ? )
  • HDRI ("hot direct reduced iron"): when the still-hot iron is immediately moved for melting into an electric arc furnace or induction furnace, to save energy. Caution: when HDRI is exposed to air, it may rapidly oxidize (=explode!). OSE Will Use This for On-Site Usage
  • Hot-briquetted iron (HBI) is a form of DRI designed for ease of shipping, handling and storage. It is made via briquetting the iron while it is still hot, then letting it cool
    • Mainly used for trade (See Iron Shortage ) due to it's stability
    • Does a Pelletized version exist/make sense?
    • OSE Will Use This For Trade and Long Term Storage

Product ecology

In's

Out's

  • Waste heat -- The DRI process generates waste heat that can potentially be used for pyrolyzing further biomass (pyrolysis = heating in absence of oxygen). Pyrolysis releases yet more syngas which can be fed back into the process. Everything is thus powered by biomass, generating biochar. In cold climates, any kind of waste heat can obviously be useful for heating winter greenhouses.

Further information is needed !

Is this actually feasible on the small scale?
Sure - thousands of these in India
Does the process take place at normal atmospheric pressure?
Yes, it can
Can a rotary kiln be designed for the village scale?
Yes, but this process does not have to take place in rotary kiln; the only thing that matters is good mixing.
Are sufficient amounts of high-grade ores or rusted steel available?
It doesn't matter. If we get the metal extraction from clays working, then we can concentrate most clays into high-grade ores.
Scalability is feasible, but efficiency may not be as good. The processes of the largest plants can also be done on a table top. The question is - at what point does it still make sense to do so? If we have access to abundant energy, feasibility may occur at a village scale (added: concentrated solar power can serve as heat source; needs methane atmosphere). (Perhaps the Charcoal Blast Furnace could handle low end, and dri, the high end?)

This appears to be a good alternative for smaller scale, lower-cost process, worth adding to our general awareness.

Other Metals

Internal Links

External links

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