Surface Instability of Serpentine in Aqueous Suspensions

Area of Science:

• Mineralogy
• Surface Chemistry
• Colloid Science

Background:

• Serpentine minerals, specifically lizardite, are common in various geological settings.
• Understanding the electrokinetic behavior of mineral suspensions is crucial for applications in mining, environmental remediation, and materials science.

Purpose of the Study:

• To investigate the electrokinetic behavior and stability of aqueous suspensions of lizardite serpentines.
• To correlate surface properties with mineral composition and alteration grade.

Main Methods:

• Crystallochemical analyses: X-ray diffraction, IR spectroscopy, Transmission Electron Microscopy (TEM), Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TG), X-ray Fluorescence (XRF).
• Electrokinetic measurements to determine surface charge and isoelectric point.
• Dissolution studies to assess mineral alteration.

Main Results:

• All studied samples were identified as lizardite-type serpentines with similar chemical compositions.
• Electrokinetic behavior is primarily governed by the surface Mg/Si atomic ratio.
• Lower isoelectric points correlate with Mg/Si ratios below the ideal lizardite value (1.5).
• Incongruent dissolution leads to surface enrichment of silicon.

Conclusions:

• The surface charge of lizardite in aqueous interfaces is directly dependent on the degree of surface alteration.
• Mineral alteration significantly impacts the electrokinetic properties and stability of serpentine suspensions.