Surface Instability of Serpentine in Aqueous Suspensions

✍ Scribed by P. Tartaj; A. Cerpa; M.T. Garcı́a-González; C.J. Serna

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 110 KB
• Volume: 231
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2000.7109

✦ Synopsis

The electrokinetic behavior and stability of aqueous suspensions containing serpentine minerals of different deposits have been studied. Crystallochemical analyses carried out by X-ray diffraction, IR spectroscopy, TEM, DTA/TG, and XRF revealed that all samples are lizardite-type serpentines with a similar chemical composition. It has been determined that the electrokinetic behavior of lizardite aqueous suspensions is mainly a function of the Mg/Si atomic ratio on surface. So, the low isoelectric point observed in some samples has been linked to values of this ratio lower than that of the ideal lizardite (Mg/Si = 1.5). Dissolution studies have shown that the removal of Mg cations from the solid at speeds faster than that theoretically expected (Mg/Si = 1.5), i.e., incongruent dissolution, is responsible for the enrichment of Si cations on surface. Therefore, it has been clearly established that the surface charge value developed in the lizardite/aqueous electrical interface is a function of the lizardite surface alteration grade.