Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H3PO4-(NaPO3)6 Composite Agent

Tan, Jiahui; Kong, Xiangfeng; Yang, Jia; Liu, Dachun; Yang, Hongwei

doi:10.3390/met16020135

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Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent

by

Jiahui Tan

^1,2

,

Xiangfeng Kong

^1,2

,

Jia Yang

^1,2,

Dachun Liu

^1,2 and

Hongwei Yang

^1,2,*

¹

Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China

²

National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China

^*

Author to whom correspondence should be addressed.

Metals 2026, 16(2), 135; https://doi.org/10.3390/met16020135

Submission received: 26 December 2025 / Revised: 20 January 2026 / Accepted: 21 January 2026 / Published: 23 January 2026

(This article belongs to the Section Extractive Metallurgy)

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Abstract

This study presents a rapid and efficient laboratory-scale process for removing lead from Pb–Sb alloy melts using a composite H₃PO₄–(NaPO₃)₆ flux. Thermodynamic analysis was combined with experimental investigation to elucidate the influence of key parameters on lead removal behavior. The Wilson equation was employed to describe the non-ideal behavior of the Pb–Sb system, enabling estimation of equilibrium lead contents and providing theoretical support for interpreting experimental trends. Under the investigated conditions (1073 K, H₃PO₄/(NaPO₃)₆ mass ratio of 2:1, and a holding time of 10 min), the Pb mass fraction was reduced from 10.0 wt.% to 0.018 wt.%, corresponding to a lead removal efficiency of 99.86%. Compared with the traditional refining processes, this method shortens the processing time and avoids the use of volatile gas reagents, demonstrating its potential for lead–antimony separation. The results provide thermodynamic and experimental insight into phosphate-based refining of crude antimony.

Keywords: antimony pyrometallurgy; lead removal agent; polyphosphate; Wilson equation; phosphates; activity coefficients

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MDPI and ACS Style

Tan, J.; Kong, X.; Yang, J.; Liu, D.; Yang, H. Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent. Metals 2026, 16, 135. https://doi.org/10.3390/met16020135

AMA Style

Tan J, Kong X, Yang J, Liu D, Yang H. Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent. Metals. 2026; 16(2):135. https://doi.org/10.3390/met16020135

Chicago/Turabian Style

Tan, Jiahui, Xiangfeng Kong, Jia Yang, Dachun Liu, and Hongwei Yang. 2026. "Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent" Metals 16, no. 2: 135. https://doi.org/10.3390/met16020135

APA Style

Tan, J., Kong, X., Yang, J., Liu, D., & Yang, H. (2026). Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent. Metals, 16(2), 135. https://doi.org/10.3390/met16020135

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Thermodynamic and Experimental Investigation of Lead Removal from Pb-Sb Alloy Using an H₃PO₄-(NaPO₃)₆ Composite Agent

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