A study of surface and liberation characteristics in coal beneficiation by oil agglomeration
Three high volatile bituminous Ohio coals of varying ash contents were beneficiated by oil agglomeration using No. 2 fuel oil, Varsol,and pentane. The degree of mineral matter removal varied with the different coal-oil combinations. To explain these differences, both surface and liberation characteristics were examined. The Washburn method for surface characterization was modified so as to remove the limitations which existed in the application of the technique to poly-disperse, heterogenous pulverized powders like the coals under study. This modified Washburn method allowed for the computation of the free energy changes involved with wetting. The effects of the differences in coals and oils could thus be distinctly quantified. The free energy approach, besides putting the study of wetting behavior on a fundamental footing, has also served to explain observed variations of the hydrophobicity of coal surfaces with rank, oxidation, etc. Fourier Transform Infrared Spectroscopy (FTIR) was used to study the inter-molecular forces behind the observed free energy changes. Studies on de-ashed coals and coals doped with minerals were also conducted. Mineral matter distribution within the coal matrix and liberation characteristics were studied using centrifugal micro-float sink techniques. By washing the agglomerates of the doped and un-doped samples in a flotation column, the degree to which entrapment of minerals in the agglomerates affected the beneficiation process was estimated.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:liberation coal oil agglomeration washburn method powders
Date of Publication:01/01/1988