Anthracite, lithotypes

In on effort to establish the mechanism of coal flotation and thus establish the basis for an anthracite lithotype separation, some physical and chemical parameters for anthracite lithotype differentiation were determined. The electrokinetic properties were determined by streaming potential methods. Results indicated a difference in the characteristics of the lithotypes. Other physical and chemical analyses of the lithotypes were mode to establish parameters for further differentiation. Electron-microprobe x-ray, x-ray diffraction, x-ray fluorescent, infrared, and density analyses were made. Chemical analyses included proximate, ultimate, and sulfur measurements. The classification system used was a modification of the Stopes system for classifying lithotypes for humic coals. 

From the foregoing it is evident that the lithotypes of anthracite are different. Differences in adsorption characteristics, surface structure, physical properties, and chemical composition conclusively demonstrate that the anthracite lithotypes are unalike and are distinct entities. It is also evident that to interpret research results of anthracite coals correctly, a petrographic knowledge of the coal is necessary. Anthracite cannot be regarded as a homogeneous substance. 

Mr. Campbell Anthracite lithotypes were investigated for their electro-kinetic characteristics to establish a basis for separation, utilizing froth flotation methods. The electrokinetic characteristics of macerals were not investigated. However, results from the lithotype work does imply that macerals have different electrokinetic characteristics. I believe electrophoretic methods could be used effectively to separate macerals for laboratory purposes. 

Coal seams display two different modes of variation rank and type. The rank of the material under consideration is anthracite. Regarding type, coal is composed of different bands of materials, distinctly contrasted in regard to physical and chemical composition. These bands are termed lithotypes in this paper, after the word coined by Seyler (2) in 1954. 

All of the anthracites used in this investigation were from Pennsylvania except two, a Russian anthracite and a Welsh anthracite. Tables I and II indicate the various designations and sources of the anthracite and lithotype samples. 

Table III. Isoelectric Points of Anthracites and Lithotypes Investigated...

Table IV. Distribution of Lithotypes in Anthracite Coal Samples...

The apparent specific gravity of the various lithotypes was measured. Results (Table VI) indicate that the order of increasing density for the lithotypes is vitrain, durain, and fusain. For Pennsylvania anthracites, the specific gravity for vitrain was found to vary between 1.36 and 1.53 for durain between 1.43 and 1.73 for fusain between 1.93 and 2.30. 

Table VIII. Ultimate Analysis of Anthracites and Lithotypes ...

John A. L. Campbell A set of 11 anthracites was investigated. Table IV lists the distribution of lithotypes in these anthracite samples. The anthracites were found generally to contain 60-80% vitrain, 10-30% durain and 1-10% fusain. 

It is felt that any anthracite seam will readily yield such lithotypes. Because fusain is relatively soft and friable and is likely to be ground to fines during handling, it may appear only as coatings or fine bands in other coal types. The durain in many cases looks like slate. Not realizing these two factors one could, without close inspection, be easily misled into believing that the major lithotype, vitrain, is the only lithotype present in a particular seam. 

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