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The Influence of Sulfate Ion on the Coal-wetting Performance of Anionic Surfactants.

Kilau HW
MISSING :30 pages
The Bureau of Mines is investigating surfactants added to water sprays to enhance the control of dust during coal mining operations. The objective of the present work was to establish the general applicability of adding sulfate ion to anionic surfactant solutions in order to improve wetting action. This was pursued through laboratory wettability testing of four anionic surfactants and one nonionic surfactant in combination with various concentrations of sulfate ion. The experimental results demonstrated that the addition of sulfate ion enhanced the wetting characteristics of all the anionic surfactants when applied to hard-to-wet coals, while easy-to-wet coal showed more complex wetting behavior. Sulfate ion in the presence of nonionic surfactant enhanced wetting only slightly or not at all. Surface tension measurements of the dilute aqueous surfactant-sulfate anion solutions indicated this property was not important in coal-wetting phenomena, as long as the value was below the critical value for coal. Sulfate ion helps surfactant reduce surface tension but primarily appears to affect wetting action by altering the adsorption characteristics of surfactant on the coal surface.
Publication Date
Document Type
IH; Report of Investigations;
Fiscal Year
Identifying No.
RI 9292
NIOSH Division
Source Name
Page last reviewed: November 26, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division