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Effect of the properties of coal surface and flocculant type on the flocculation of fine coal

University of British Columbia

Three coal samples, selected out of eight with well-characterized surface properties, were used in flocculation tests. A synthetic mixture of coal and silica was used in the selective flocculation experiments. The flocculants tested included: a hydrophilic polyacrylamide (PAM) and a semihydrophobic (F1029-D) flocculants and a totally hydrophobic latex prepared by emulsion polymerization (FR-7A). Good hydrophobic agglomeration and selectivity were observed with the totally hydrophobic latex on non-oxidized hydrophobic coal only; increased coal hydrophilicity clearly affected agglomeration and selectivity. For the polyelectrolyte and the semihydrophobic flocculants, the flocculation vs. shear rate curves exhibited a maximum, while for the totally hydrophobic latex the degree of flocculation increased continuously over the whole tested range. The flocculation versus flocculant dosage curves displayed a maximum for the polyelectrolyte whereas for both semi-hydrophobic polymer and for the latex the degree of flocculation did not vary significantly beyond a certain dosage. Flocculation was found to be pH dependent: while better flocculation was observed in acidic solutions, better selectivity (deashing) was obtained in alkaline pH ranges.

Thesis/Dissertation

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2009-02-15

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http://hdl.handle.net/2429/4606

Materials Engineering

University of British Columbia

UBCV

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