Work

Liquid–liquid extraction of boron from synthetic brines: mass transfer control and extraction mechanisms

Year: 2026

Type: article

Abstract: Boron recovery from natural brines is of increasing industrial interest, yet the factors controlling its extraction efficiency remain insufficiently understood. In this work, the kinetics and equilibrium behaviour of boron extraction from synthetic brines mimicking the Salar de Hombre Muerto were investigated using 2-ethylhexan-1-ol and 2-butyloctan-1-ol diluted in kerosene. Long-contact experiments under intense stirring showed that apparent equilibrium was reached after approximately 4 h. However, experiments performed in a Lewis cell under controlled hydrodynamic conditions revealed substantially slower extraction kinetics and a strong dependence of the overall extraction rate on stirring rate. Using the mass-transfer model described in this work, the overall mass-transfer coefficient for 2-ethylhexan-1-ol increased from 15.27 × 10 −5 mm s −1 at 50 rpm to a maximum of 35.91 × 10 −5 mm s −1 at 100 rpm, followed by a decrease to 31.61 × 10 −5 mm s −1 at 120 rpm. Comparison of the two alcohols under identical hydrodynamic conditions showed that 2-ethylhexan-1-ol provided higher boron extraction at longer contact times, demonstrating the influence of extractant structure on the overall mass-transfer behaviour. 1 H NMR analysis indicated that boron was predominantly extracted through solvation (approximately 98%), whereas esterification accounted for only a minor contribution (approximately 2%). Slope analysis further suggested the coexistence of multiple solvated species rather than a single well-defined extracted complex. Overall, the results indicate that boron extraction reflects the combined influence of equilibrium behaviour, hydrodynamic mass transfer, and extractant-dependent molecular interactions.

Source: Hydrometallurgy

DOI: 10.1016/j.hydromet.2026.106944

Authors: Abdoul Fattah Kiemde, Paola González, Younes Bouizi, Mario Avila-Rodriguez, Alexandre Chagnes

Institutions: Centre National de la Recherche Scientifique, GeoRessources, Université de Lorraine, Universidad de Guanajuato, Laboratoire de Cristallographie, Résonance Magnétique et Modélisations

Language: English

Topic: Extraction and Separation Processes

Subfield: Metals and Alloys

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,350

Funder: Université de Lorraine