Richard D. Coleman

Agglomeration-flotation: recovery of hydrophobic components from oil sands fine tailings

Laboratory agglomeration-flotation tests were used to evaluate the recovery of residual bitumen from a sample of Suncor oil sands fine tailings, using ground coal as a bitumen absorbent. To improve its effectivness, the coal was preconditioned with no. 2 fuel oil, subjected to 30 s high-shear mixing and collected by flotation over 3 min. This oil-conditioned coal was then contacted with mature fine tailings for 5 min with low-shear mixing. Flotation for 5 min resulted in the recovery of 93% of the residual bitumen, compared with 85% after 40 min mixing achieved in earlier tests. Equipment to accomplish this separation has already been designed, scaled and operated for fine coal recovery from washery wastes.

The effect of particle size and pH on the removal of pyrite from coal by conditioning with bacteria followed by oil agglomeration

Abstract The removal of 90% of the pyrite from coal by bacterial conditioning followed by oil agglomeration is attainable in Minto coal only if it is ball milled in the laboratory to an average particle size of about 5 μm. In grinding to industrially practical sizes of about 8 to 10 μm, the maximum amount of pyrite removed was about 50%. The contribution of the bacterial conditioning step was highly dependent on the pH of the feed slurry. A positive effect of bacterial conditioning was greatest at pH 2. At pH 10, the presence of bacteria was detrimental to desulfurization by oil agglomeration. Bacterial conditioning does not involve pyrite oxidation by Thiobacillus ferrooxidane because the pH of a coal—water mixture was normally above pH 5 for best pyrite depression where these bacteria are physiologically inactive, and because conditioning was achieved equally well with cells of Thiobacillus acidophilus and Escherichia coli.

Treatment of crude petroleum/water emulsions by agglomeration methods using fine coal

Persistent crude petroleum-water emulsions are produced in the recovery and extraction of heavier oils, for example, in the hot water processing of surface mined oil sands and during in-situ methods such as steam- or water-flooding. Over the past few years, much attention has been directed to the oil agglomeration method as a means of recovering and upgrading fine coal in water suspensions. The work reported here concerns the use of crude petroleum from produced emulsions in the coal agglomeration process. Two problems are adddressed in this way. Not only is oil recovered and emulsions broken in the case of the produced emulsions, but the coal is also benificiated through the rejection of water and inorganic impurities because of the selectivity of the agglomeration technique. Laboratory-scale experiments are reported using three different samples of produced emulsion from western Canada and a fine coal from waste tailings of a coal preparation plant. Results of the experiments are considered from the poi...

Beneficiation of coal-heavy oil coprocessing residue by oil-phase agglomeration☆

Surface characterization techniques (scanning electron microscopy and X-ray photoelectron spectroscopy) were used to examine toluene-insoluble solids from coprocessing of coal and heavy oil in order to evaluate their physical separation potential. Washability studies, using float-sink tests, were also carried out to provide an empirical estimate of the ash separation attainable. On the basis of the results, agglomeration tests were performed in an attempt to optimize the beneficiation of the organic matter in the residue pitch. Ash rejection in these tests ranged from 30 to 40%. Analysis of the ash from the agglomerated and reject fractions suggested that most of the iron was retained in the agglomerates.

MEASUREMENT OF PARTICLE SIZE DISTRIBUTION IN COAL OIL WATER FUELS BY FOUR METHODS

ABSTRACT Four methods were used to measure the solids particle size distribution in coal-ol1-water fuel. Both dry and wet screening were utilized for the coarser particles while four different instrumental methods were used to measure the finer particles in diluted liquid suspension. The wet stages of the analyses included both solvent-diluted organic suspensions and measurement after inversion to an aqueous system. Consistent differences in the absolute values of particle size were observed between the four procedures. Possible reasons for these differences are discussed.