PROCEDURE FOR ESTIMATING DISTRIBUTION OF MICROELEMENTS IN ORGANIC AND MINERAL SUBSTANCES OF COAL

The information on distribution of microelements (ME) in organic and mineral substances of coal and other solid mineral fuels helps understanding general geochemical mechanisms of ME accumulation in the caustobioliths and selecting technologies for their integrated use at the minimized environmental impact. Currently there are no methods for the quantitative division of coal and other solid combustible minerals into organic and mineral substances with the quantitative recovery of ME contained in initial specimen. In this regards, the routine method is separation to different density fractions, and a fraction having less density and, accordingly, smaller ash content has higher content of organic substances. The quantitative estimation of ME distribution (belonging to an organic or a mineral substance) is based on two criteria: reduced content of an i-th element in a g-th fraction (Yig) and recovery of an i-th element in a g-th fraction (Uig) calculated from the relations: where Сiо and Сig —contents of the i-th element in initial coal and in the g-th fraction; Ɣg—yield of the g-th fraction.

A fraction is an i-th ME concentrator in case when (Yig) ≥1.0. When (Uig) ≥ 50% or ≥ 0.5 g, the fraction is assumed the i-th ME carrier.

The experimental analysis of lignite from Low Ile deposit in Kazakhstan shows that the quantity of ME (Au, Ag, Re and other) in organic and mineral substances vary within wide ranges in coal specimens sampled at different points of the same deposit. For instance, a silver concentrator is assumed the heavier fraction out of two samples with the density more than 1.7 g/cm3 and out of two samples of medium density (1.4–1.7 g/cm3), and silver carriers are fractions with the density of 1.4–1.7 g/cm3 out of four samples and one sample with the density more than 1.7 g/cm3. Unequal content of ME in organic and mineral substances in the samples from the same deposit is revealed for all test ME (Au, Re, Mo, Cd, Ag). A reasoned conclusion of the quantitative distribution of ME in organic and mineral substances of coal even in terms of the same deposit can only be drawn based on the test data on a number of specimens sampled at different points of the deposit.

Keywords

Microelements, distribution, organic and mineral substances, difference, deposit.

Issue number: 2
Year: 2018
ISBN:
UDK: 622.33:550.4:552.57.58
DOI: 10.25018/0236-1493-2018-2-0-148-155
Authors: Silyutin S. A.

About authors: Silyutin S.A., Candidate of Technical Sciences, Head of Department, e-mail: silutinsa@suek.ru, OJSC «Siberian Coal Energy Company» (SUEK), Moscow, Russia.

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