Dithiophosphinate-pyrite interaction: voltammetry and DRIFT spectroscopy investigations at oxidizing potentials

Area of Science:

• Mineral electrochemistry
• Surface chemistry
• Adsorption phenomena

Background:

• Pyrite is a key mineral in various industrial processes.
• Understanding surface interactions is crucial for mineral processing and environmental remediation.
• Dithiophosphinate (DTPI) is a potential collector agent.

Purpose of the Study:

• To investigate the electrochemistry of dithiophosphinate (DTPI) adsorption on pyrite.
• To determine the effect of pH on DTPI adsorption and surface species.
• To elucidate the mechanism of DTPI adsorption and its impact on electron transfer.

Main Methods:

• Cyclic voltammetry (CV) was used to study electrochemical behavior.
• Diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy identified surface species.
• Experiments were conducted under acidic, neutral, and alkaline conditions.

Main Results:

• Pyrite surfaces were covered by ferric oxyhydroxide species.
• Irreversible DTPI adsorption and partial electron transfer inhibition were observed.
• DTPI and its dimer were identified as major adsorbed species, with maximum adsorption in acidic solutions.

Conclusions:

• DTPI adsorption on pyrite is strongly pH-dependent.
• High pH leads to significant surface oxidation, reducing DTPI adsorption.
• Surface species and adsorption mechanisms were elucidated for pyrite-DTPI interactions.