Demineralization, coal

Figure 3. Effect of hydrogen pressure on conversion of Liddell coal (O), untreated coal (+) demineralized coal (A), hand-picked vitrain. Reaction temperature = 400°C reaction time = 4 hr.

Flotation of Naturally Hydrophobic Minerals. Flotation response of naturally hydrophobic minerals correlates very well with elec-trokinetic measurements. Figure 3 shows that the flotation of coal correlates well with zeta potential of demineralized coal (5.). The flotation rate is maximum where the zeta potential is zero and it decreases with increase in the magnitude of the zeta potential. Similar observations were made earlier by Chander and Fuerstenau (6 ) for the flotation of molybdenite. The decrease in flotation rate with increase in zeta potential is because of the electrical double layer repulsion between the charged particle and the air bubble. 

Table I. Analytical and Maceral Analyses of Demineralized Coals...

Samples. Two of the coals used 1n this study were obtained from the Penn State Coal Sample Bank, an HVA bituminous coal (PSOC 1103) from the Upper Elkhorn 3 seam in Eastern Kentucky and an HVA bituminous coal (PSOC 828) from the Brazil Block seam in Indiana. A third coal from which vitrinite and fusinite were hand picked was an Illinois No. 2 seam HVC bituminous coal from Northern Illinois. Also, resinite and vitrinite samples were hand picked from a Hiawatha seam bituminous coal from the King 6 mine in Utah. Finally, the alginite sample was obtained from an Ohio No. 5 seam (PSOC-297) coal by 06C (2,5). All of the elemental and petrographic analyses are presented in Table I. The details of the sink-float technique have been reported previously (1). Typically, a 3 micron particle size demineralized coal Ts centrifuged in aqueous CsCl2 solution of the appropriate density with a small amount of surfactant added to disperse the coal particles. The exinites in the float are... 

Aliphatic stretching, FTIR of vitrinite, 103-12 Alkyl phenols, Py-MS, 153f Analytical analyses of demineralized coals, density fractions, 71t Aromatic adjacent hydrogen in... 

The filled symbols represent data for the demineralized coal.)... 

---