In lead concentrate cleaning, achieving efficient separation of galena from realgar—both significant naturally floatable minerals-relies critically on selective galena depression. This study introduces dimercaptosuccinic acid (DMSA) as a novel organic depressant by leveraging its distinct carbon-sulfur hybridization compared to diethyldithiocarbamate (DDTC). Quantum chemical analyses reveal that the sp3-hybridized sulfur in DMSA exhibits enhanced p-orbital reactivity, enabling stronger chemical adsorption on galena via Pb-S bonding. At pH 6.5, DMSA (4 mg/L) achieved optimal separation with a separation index of 11.88, outperforming DDTC (10 mg/L). FTIR/XPS confirmed DMSA’s chemisorption on galena, while theoretical calculations highlighted its superior Pb-S bond strength compared to DDTC. Notably, DMSA’s lower dosage and reduced environmental impact position it as a sustainable alternative to inorganic depressants. This work provides fundamental insights into sulfur orbital-driven adsorption mechanisms, advancing the rational design of eco-friendly flotation reagents.
In this work, 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) was explored as a novel sphalerite depressant in the selective flotation of galena from sphalerite. The separation performances were investigated by single and synthetic flotation tests. The depression mechanism was examined by Fourier Transform Infrared spectroscopy (FTIR), zeta potential and X-ray Photoelectron Spectroscopy (XPS) analysis. The flotation test results showed that PBTCA was an effective sphalerite depressant with good selectivity at broad pH range, which could achieve satisfactory separation results. Zeta potential and FTIR results indicated that PBTCA was more prone to adsorb on sphalerite surface than that of galena. In addition, SIBX could replace adsorbed PBTCA on the galena surface while it was impossible to substitute that on the sphalerite surface, which rendered sphalerite surface hydrophilic and enlarged the floatability difference. XPS analysis manifested that PBTCA was adsorbed on sphalerite surface through the strong complexation between carboxyl, phosphonic acid groups and Zn sites on sphalerite surface, forming C-O-Zn or P-O-Zn bond.
In this work, an environment-friendly sphalerite depressant 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was exploited in the flotation separation of sphalerite and galena . The flotation performances of sphalerite and galena treated by HEDP were investigated by mineral flotation tests. The depression mechanisms of HEDP on sphalerite were investigated by various characterization techniques such as zeta potential tests, Fourier Transform Infrared Spectrometer (FTIR), X-ray Photoelectron Spectroscopy (XPS) analysis, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and density functional theory (DFT) calculation. Flotation tests showed that HEDP selectively depressed sphalerite but almost did not influence the flotation of galena in sodium isobutyl xanthate (SIBX) system, which achieved effective flotation separation results. zeta potential tests and FTIR results proved the preferential adsorption of HEDP on sphalerite surface, but the pre-adsorbed of HEDP on galena could be replaced by SIBX easily. XPS, ToF-SIMS analysis and DFT calculation demonstrated that HEDP was coordinated with Zn atom through two different phosphonic acid group, forming a six membered chelating ring.
Effective collectors are crucial for efficient galena (PbS) flotation beneficiation. This study introduces a novel synergistic mixed collector system, comprising sodium diethyl dithiocarbamate (DTC) and O,O’-bis(2-butoxyethyl) ammonium dithiophosphate (BEAT), for enhancing galena recovery and selectivity against sphalerite. Microflotation tests demonstrated that a premixed DTC/BEAT system (1:1 M ratio, at the total dosage of 2 × 10 −5 mol/L) at pH ∼ 7.0 achieved a remarkable galena recovery of 94.23 %, significantly outperforming single collectors. This synergistic effect was further validated through bench-scale flotation of lead–zinc sulfide ores. Wettability results indicated that the mixed DTC/BEAT scheme induced superior hydrophobicity on galena surfaces compared to either single collector. Zeta potential, FTIR and XPS spectra verified the co-adsorption of both DTC and BEAT collectors onto the galena surface. The findings provide an effective strategy for improving galena flotation efficiency in mineral processing.
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