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Linkified early mentions of the chemical elements involved in the process, as well as the term "tuyure" |
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[[File:AOD (Argon, oxygen decarburisation) vessel.jpg|thumb|Refining of a 9.5%CrMoWVNbN steel in an argon, oxygen decarburisation (AOD) vessel]]
'''Argonoxygen decarburization''' ('''AOD''') is a process primarily used in [[stainless steel]] [[steel making|making]] and other high grade alloys with oxidizable elements such as [[chromium]] and [[aluminium]]. After initial melting the metal is then transferred to an AOD vessel where it will be subjected to three steps of refining; [[decarburization]], [[Reduction (chemistry)|reduction]], and [[desulfurization]].
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=== Decarburization ===
Prior to the decarburization step, one more step should be taken into consideration: ''de-siliconization'', which is a very important factor for refractory lining and further refinement.
The decarburization step is controlled by ratios of [[oxygen]] to [[argon]] or [[nitrogen]] to remove the [[carbon]] from the metal bath. The ratios can be done in any number of phases to facilitate the reaction. The gases are usually blown through a top lance (oxygen only) and [[tuyere
:4 Cr<sub>(bath)</sub> + 3 O<sub>2</sub> → 2 Cr<sub>2</sub>O<sub>3(slag)</sub>
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=== Desulfurization ===
Desulfurization is achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath.
:S<sub>(bath)</sub> + CaO<sub>(slag)</sub> → CaS<sub>(slag)</sub> + O<sub>(bath)</sub>
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== History ==
The AOD process has a significant place in the history of steelmaking, introducing a transformative method for refining stainless steel and shaping the industry's landscape.
=== 1960s ===
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== Additional uses ==
In additional to its primary application in the production of stainless steel, many various additional uses have been found for AOD across different industries and materials.
=== Carbon Capture and Utilization ===
AOD slag has shown promising potential for usage as a carbon-capture construction material due to its high capacity for CO2 and its low cost. Carbonation curing, a process utilizing CO2 as a curing agent in concrete manufacturing, enhances the chemical properties of stainless steel slag by stabilizing it. During carbonation, g-C2S (di-calcium silicate) in the slag reacts with CO2 to produce compounds like calcite and silica gel, resulting in increased compressive strength and improved durability of cementitious materials. The incorporation of AOD slag as a replacement material in ordinary Portland cement (OPC) during carbonation curing has been studied, demonstrating positive effects on strength and reduced porosity.<ref>{{cite journal |last1=Moon, Choi |first1=E.-J, Y.C |title=Development of carbon-capture binder using stainless steel argon oxygen decarburization slag activated by carbonation |journal=Journal of Cleaner Production |date=2018 |volume=180 |
=== Cementitious Activity and Modifiers ===
AOD slag exhibits cementitious activity, but its properties can be changed by modifiers. Studies have focused on the impact of modifiers, such as B2O3 and P2O5 on preventing the crystal transition of β-C2S and improving the cementitious activity of the slag. Addition of B2O3 and P2O5 has shown curing effects and increased compressive strength. These findings suggest that proper selection of modifiers can enhance the performance of stainless steel slag in cementitious applications.<ref>{{cite journal |last1=Baciocchi, Costa, Di Bartolomeo, Polettini, Pomi |first1=R., G., E., A. R. |title=Carbonation of Stainless Steel Slag as a Process for CO2 Storage and Slag Valorization. |journal=Waste and Biomass Valorization |date=2010 |volume=1 |issue=4 |
=== Chromium Leachability and Carbonation ===
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{{reflist}}
{{Iron and steel production}}
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