Efficient metallurgical extraction of vanadium slag: Experimental phase diagram study and thermodynamic modeling of Na2O-K2O-V2O5 system

PEI Guishang; Sammpath Kumar BHARATH; LI Zhuoyang; JIAO Mengjiao; XIANG Junyi; YAN Zhiming; LÜ Xuewei

doi:10.7513/j.issn.1004-7638.2025.06.003

Volume 46 Issue 6

Dec. 2025

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PEI Guishang, Sammpath Kumar BHARATH, LI Zhuoyang, JIAO Mengjiao, XIANG Junyi, YAN Zhiming, LÜ Xuewei. Efficient metallurgical extraction of vanadium slag: Experimental phase diagram study and thermodynamic modeling of Na2O-K2O-V2O5 system[J]. IRON STEEL VANADIUM TITANIUM, 2025, 46(6): 29-39, 65. doi: 10.7513/j.issn.1004-7638.2025.06.003

Citation:

PEI Guishang, Sammpath Kumar BHARATH, LI Zhuoyang, JIAO Mengjiao, XIANG Junyi, YAN Zhiming, LÜ Xuewei. Efficient metallurgical extraction of vanadium slag: Experimental phase diagram study and thermodynamic modeling of Na₂O-K₂O-V₂O₅ system[J]. IRON STEEL VANADIUM TITANIUM, 2025, 46(6): 29-39, 65. doi: 10.7513/j.issn.1004-7638.2025.06.003

Citation:

PEI Guishang, Sammpath Kumar BHARATH, LI Zhuoyang, JIAO Mengjiao, XIANG Junyi, YAN Zhiming, LÜ Xuewei. Efficient metallurgical extraction of vanadium slag: Experimental phase diagram study and thermodynamic modeling of Na₂O-K₂O-V₂O₅ system[J]. IRON STEEL VANADIUM TITANIUM, 2025, 46(6): 29-39, 65. doi: 10.7513/j.issn.1004-7638.2025.06.003

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Efficient metallurgical extraction of vanadium slag: Experimental phase diagram study and thermodynamic modeling of Na₂O-K₂O-V₂O₅ system

doi: 10.7513/j.issn.1004-7638.2025.06.003

1.
Warwick Manufacturing Group, University of Warwick, Coventry CV4 7AL, UK
2.
College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
3.
School of Metallurgy and Power Engineering, Chongqing University of Science and Technology, Chongqing 401331, China

More Information

Received Date: 2025-10-31
Accepted Date: 2025-11-25
Rev Recd Date: 2025-11-25

Available Online: 2025-12-31

Publish Date: 2025-12-31

Abstract

Abstract

Accurate and reliable thermodynamic databases are of significance for optimizing vanadium extraction and synthesizing vanadate materials. This study employed sealed platinum crucibles combined with X-ray diffraction (XRD) and differential thermal analysis (DTA) to confirm the presence of K₃V₅O₁₄ in the K₂O-V₂O₅ system, melting temperature of K₂V₈O₂₁ and KVO₃ were also determined as 532.4 ℃ and 516.5 ℃, respectively. Modified Quasichemical Model (MQM) was adopted, incorporating short-range ordering of second-neighboring cations in solution to describe changes in Gibbs free energy of solution phases. Thermodynamic model for the Na₂O-K₂O-V₂O₅ system was then developed in the framework of CALPHAD (Calculation of Phase Diagrams) methodology, reproducing experimental data across the entire composition range of the system. A self-consistent set of thermodynamic parameters for all phases in the system was obtained, ultimately establishing a reliable thermodynamic database. Furthermore, the developed database was applied to optimize sodium-roasting of vanadium slag at elevated temperatures, clarifying the phase evolution of vanadium-containing phases and identifying optimal operating temperature windows.
- Na₂O-K₂O-V₂O₅ system,
- phase diagram,
- thermodynamic optimization,
- CALPHAD

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References(63)

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