Purification of lanthanum chloride solution through tertiary amine extraction: thermodynamic and graded assessment

N. Zulkifli; N. Shoparwe; A.H. Yusoff; A.Z. Abdullah; M.N. Ahmad

doi:10.31643/2028/6445.03

Authors

N. Zulkifli Universiti Malaysia Kelantan
N. Shoparwe Universiti Malaysia Kelantan
A.H. Yusoff Universiti Malaysia Kelantan
A.Z. Abdullah Universiti Sains Malaysia
M.N. Ahmad International Islamic University of Malaysia

DOI:

https://doi.org/10.31643/2028/6445.03

Keywords:

lanthanum chloride, solvent extraction, zinc, N235, McCabe-Thiele.

Abstract

Purification of lanthanum chloride from high-load zinc contaminants remains a major challenge in producing grade 5N lanthanum oxides. This study investigates the process of matrix-driven solvent extraction using tertiary amine N235 to treat a 1.41 M rare earth oxides (REO) industrial lanthanum chloride feed containing 3000 mg/L zinc. Thermodynamic modelling with Medusa Hydra and Langmuir isotherms revealed that the high chloride activity (> 4 M) of the matrix induced significant changes in coordination towards the extractable [ZnCl₄]^2- complex. This transition has a spontaneous Gibbs free energy of -14.68 kJ/mol. While the two-stage counter-current flow sheet meets the industry target of less than 50 mg/L zinc, the five-stage configuration achieves a four-log reduction to 0.23 mg/L, effectively achieving 99.999% purity. This reagent's lean approach, using water-induced stripping, offers a sustainable and mathematically validated framework for ultra-high purity rare earth finishes.

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Author Biographies

N. Zulkifli, Universiti Malaysia Kelantan

PhD candidate at the Centre for Gold, Rare Earths and Materials Technopreneurship (GREAT), Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli 17600 Kelantan, Malaysia. ORCID ID: https://orcid.org/ 0009-0009-4772-0578

N. Shoparwe, Universiti Malaysia Kelantan

Associate Professor at Gold, Rare Earth and Material Technopreneurship Centre (GREAT), Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli 17600 Kelantan, Malaysia. ORCID ID: https://orcid.org/ 0000-0002-4329-2459

A.H. Yusoff, Universiti Malaysia Kelantan

Associate Professor at Gold, Rare Earth and Material Technopreneurship Centre (GREAT), Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli 17600 Kelantan, Malaysia. ORCID ID: https://orcid.org/0000-0003-0229-886X

A.Z. Abdullah, Universiti Sains Malaysia

Professor at the School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia.

M.N. Ahmad, International Islamic University of Malaysia

Associate Professor at the Sustainable Computational Nanotechnology and Chemistry Research Group (SuNCoM), Department of Chemistry, Faculty of Science, International Islamic University Malaysia, 25200 Kuantan, Pahang, Malaysia. ORCID ID: https://orcid.org/ 0000-0001-5742-0346

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