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Title: ELECTRONIC SURFACE STRUCTURES OF COAL AND MINERAL PARTICLES

Technical Report ·
DOI:https://doi.org/10.2172/834520· OSTI ID:834520

Surface science studies related to tribocharging and charge separation studies were performed on electrostatic beneficiation of coal. In contrast to other cleaning methods, electrostatic beneficiation is a dry cleaning process requiring no water or subsequent drying. Despite these advantages, there is still uncertainty in implementing large-scale commercial electrostatic beneficiation of coal. The electronic surface states of coal macerals and minerals are difficult to describe due to their chemical complexity and variability. The efficiency in separation of mineral particles from organic macerals depends upon these surface states. Therefore, to further understand and determine a reason for the bipolar charging observed in coal separation, surface analysis studies using Ultra-violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS) were performed on coal samples and several materials that are used or considered for use in tribocharging. Electrostatic charging is a surface phenomenon, so the electronic surface states of the particles, which are influenced by the environmental conditions, determine both polarity and magnitude of tribocharging. UPS was used to measure the work function of the materials as typically used in ambient air. XPS was used to determine the surface chemistry in the form of contamination and degree of oxidation under the same environmental conditions.

Research Organization:
University of Arkansas (US)
Sponsoring Organization:
(US)
DOE Contract Number:
FG22-96PC96202
OSTI ID:
834520
Resource Relation:
Other Information: PBD: 1 Apr 2001
Country of Publication:
United States
Language:
English