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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

COLLECTORS FOR ENABLING FLOTATION OF OXIDIZED COAL

Dube, Raghav M. 01 January 2012 (has links)
The coalburg seam coal is an example of difficult to float bituminous coal. Laboratory tests conducted on coalburg flotation feed sample revealed recovery values around 28% with 15% product ash when using fuel oil as collector under natural pH conditions. A detailed study showed that increasing pH from natural value of 5.6 to 7.5 provided a significant improvement in recovery of approximately 32 absolute percentage points. The improvement is believed to be result of the release of humic acids from the surface and the dispersion of clay particles thereby leaving a more hydrophobic surface. Based on the tests conducted with various commercially available collectors, oleic acid was selected as a model collector for oxidized coals. Conventional flotation tests found an increase in combustible recovery of 10 absolute percentage points above the pH improvement using 4:1 blend of fuel oil and oleic acid. The problem of higher ash in conventional cell product due to entrainment was minimized by the use of wash water in a flotation column. A flotation concentrate containing less than 7.5% ash was produced while recovering around 75% of the combustible material. Further testing using fatty acids-fuel oil blend also showed evidence of a near 200% increase in flotation rate.

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