Selective flotation of carbonate minerals

This study explores the selective flotation of carbonate minerals-dolomite, magnesite, and calcite using amino acid-based single- and double-headed collectors. The separation efficiency was evaluated using microflotation experiments, ζ potential measurements, UV–Vis spectroscopy, FTIR spectroscopy, and molecular modelling. The study aimed to understand how the molecular architecture of collectors influences their adsorption behaviour on mineral surfaces, leading to selective flotation.

Flotation recoveries were measured at both natural and pH 10.5 conditions. The monocarboxylate collector (C₁₂GlyNa) demonstrated high but non-selective recovery across all three minerals. In contrast, the double-headed collector, disodium N-dodecyl aminomalonate (C₁₂MalNa₂), exhibited strong selectivity, particularly for magnesite, due to optimal geometric matching between its head groups and the Mg-Mg atomic distances on the mineral surface. The amount of collector adsorbed was determined by UV–Vis analysis, while FTIR confirmed surface adsorption through characteristic alkyl stretching bands. ζ potential measurements supported these findings, showing that increased adsorption led to greater negative charge development on mineral surfaces. Molecular modelling further revealed that selective adsorption occurs when the collector's head group spacing aligns with metal-metal distances on the mineral surface, enabling effective electrostatic interactions.

These results highlight the potential for designing tailored collectors based on molecular recognition principles, offering a pathway for more efficient and selective flotation of carbonate minerals.