Electrochemically recycling degraded superalloy and valorizing CO2 in the affordable borate-modified molten electrolyte

Integrating electrochemical reduction of CO 2 and electrochemical oxidation to recycle degraded superalloys is a promising solution to ease resource scarcity and safeguard environmental sustainability. Herein, we propose an electrochemical technique for the conversion of bulk superalloy scraps and C...

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Bibliographic Details
Published in:Tungsten 2024-06, Vol.6 (2), p.382-393
Main Authors: Chen, Xiang, Sun, Yuan, Wang, Long, Qu, Xin, Zhao, Yan, Xie, Hong-Wei, Wang, Di-Hua, Yin, Hua-Yi
Format: Article
Language:English
Subjects:
Alkalinity
Alloys
Borax
Calcium carbonate
Calcium chloride
Carbon dioxide
Chemical reduction
Chemistry and Materials Science
Corrosion
Electrochemical oxidation
Electrolytes
High temperature
Leachates
Materials Engineering
Materials Science
Metal scrap
Metallic Materials
Metals
Molten salt electrolytes
Molten salts
Morphology
Nickel
Nuclear Chemistry
Original Paper
Oxidation
Particle and Nuclear Physics
Raw materials
Sulfation
Sulfation roasting
Superalloys
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Summary:Integrating electrochemical reduction of CO 2 and electrochemical oxidation to recycle degraded superalloys is a promising solution to ease resource scarcity and safeguard environmental sustainability. Herein, we propose an electrochemical technique for the conversion of bulk superalloy scraps and CO 2 into oxide powder at the anode and solid carbon at the cathode, respectively. In particular, a borax-modified CaCl 2 -based molten salt electrolyte is used for enhancing the electrochemical oxidation of superalloy scraps. At a temperature of 700 °C and a voltage of 2.8 V, 90.55 wt.% of alloy scraps were oxidized in a molten CaCl 2 –NaCl–CaCO 3 –Na 2 B 4 O 7 with an acid–base ratio ( K a/b ) of 1. The synergy of Cl − and B 4 O 7 2− of electrolyte prevents the passivation of the alloy anode and enables continuous oxidation. Furthermore, the Ni and Co in the anode products are recovered by sulfation roasting with recovery efficiencies of 85.58% and 95.27% for Ni and Co, respectively. Overall, modulating the alkalinity of the electrolyte for enhancing oxidation/pulverization of alloy scrap anode provides new insight into electrochemically recovering superalloy scraps.
ISSN:2661-8028
2661-8036
DOI:10.1007/s42864-023-00240-2