Coal, analyses grading

A sample of medium-grade bituminous coal analysis is as follows ... 

Media Si. Media are suppHed in several size grades and the grade used varies at each plant. The finer grades improve media stabiUty, but finer particles are more difficult to recover and the feed rate of these finer-grade slurries should be reduced by a factor of 0.5—0.75 to maintain magnetic recovery. A typical size analysis as used in various heavy-media separation plants treating coal (qv) is given in Table 4. 

Beryllium (Be), 3 637-661. See also Beryllium compounds analysis, 3 645-647 chemical reactions, 3 639-640 in coal, 6 718-719 commercial grades, 3 644t economic aspects, 3 644-645 effect on copper resistivity, 7 676t fabrication, 3 642-644 in galvanic series, 7 805t handling, 3 647... 

Most of the analyses of Antarctic coal were based on blocks of transportable size taken from surface outcrops. In earlier work, sections of purer coal were cut from the blocks and submitted for analysis. In later work, selected blocks were crushed, and a float fraction of purer coal was submitted to provide analytic data from each deposit. These samples, while not useful for determining coal grade, may be adequate for indicating rank. Practically all of the Antarctic coal, with the exception of that at Amery (which may represent high volatile bituminous coal), corresponds to medium volatile bituminous or higher rank. The high apparent rank Antarctic coal may be classified according to conventional ASTM standards of rank based on proximate analysis, but it seems clear that these results serve only as a first approximation. 

Classification by grade covers the quality of the coal as detd by size,proximate analysis, ultimate analysis, ash-softening temp, ability to carbonize, calorific value, etc (See Ref 26, D339-37, p 1232)... 

Table 1 reports the elemental analysis and the ash content of the samples studied. The ash content is high for each sample due to the low grade coal precursor. 

In practice, there are several types of data acquired from such an analysis. The first group is a single parameter measurement at standardized points defined by concentration or time, which are used to compare coals and classify them. This is useful if a broad database already exists and the new sample can be graded with reference to known reactivity behavior from plant operation. 

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