The influence of oxygen defect states on the surface charge of alkali halides

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Journal of Colloid and Interface Science

DOI:https://doi.org/10.1006/jcis.1996.0460· OSTI ID:379544

Veeramasuneni, S; Yalamanchili, M R; Miller, J D ^[1]

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1. Univ. of Utah, Salt Lake City, UT (United States)

The sign of the surface charge for alkali halides in their saturated brines has been established from nonequilibrium electrophoresis measurements, and on this basis the flotation response of alkali halides was explained based on the adsorption of oppositely charged collector colloids by heterocoagulation. These surface charge results for alkali halides are generally as expected from simplified lattice ion hydration theory with some exceptions, specifically LiF, KCl, NaCl, KBr, RbBr, KI, and RbI. The presence of natural oxygen defect states in the crystal lattice and the inaccuracies involved in the gaseous ion hydration free energy values used appear, in the past, to be responsible for these deviations. The presence of natural oxygen defect states in KCl, KBr, RbBr, and RbI, as characterized by UV/Vis absorption, was found to account for their anomalous surface charge. Further, other positively charged alkali halides, LiF, NaCl, and KI, were found to be free of oxygen defect states. Nevertheless, oxygen defects can be created in these alkali halides to make them negatively charged, and this has been demonstrated for NaCl. Such negatively charged NaCl can be readily floated with positively charged amine collector colloids, thus confirming the surface charge/collector colloid adsorption theory.

• OSTI ID: 379544
• Journal Information: Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 1 Vol. 182; ISSN 0021-9797; ISSN JCISA5
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
40 CHEMISTRY
ABSORPTION SPECTROSCOPY
ALKALI METAL COMPOUNDS
CRYSTAL DEFECTS
FLOTATION
HALIDES
OPTIMIZATION
ORE PROCESSING
POTASSIUM CHLORIDES
SODIUM CHLORIDES
SURFACE POTENTIAL