Community Research and Development Information Service - CORDIS


The coal industry produces a large quantity of sludge (the fine residue of coal washing), which is difficult to make use of due to its characteristics (fineness and high ash content). In many mining areas, stocks of this product have grown considerably, taking up a large amount of space and causing a not insignificant risk of environmental pollution.

We are working on applying separation techniques based on surface properties, such as flotation, flocculation and selective agglomeration. The various analyses carried out on samples collected show that the sludge heaps with which this study deals can, as far as we are concerned, be considered homogeneous. This material is very fine with an average ash content of approximately 45%, and an average lower calorific value of 17 600 kJ/kg. The sludge is slightly sulphurous, with a sulphur content of the order of 0.65%. Two methods of evaluating the level of oxidation of sludge have been developed, alkaline attack and extraction with organic solvents. The study has shown that the treated sludge had a low level of oxidation. .

Additional information

Authors: AUQUIER W, ISSeP, Liège (BE);TRAN H, ISSeP, Liège (BE);BRUNELLO J, ISSeP, Liège (BE)
Bibliographic Reference: EUR 17159 FR (1997) 295pp., FS, ECU 49.50
Availability: Available from the (2)
ISBN: ISBN 92-826-9507-7
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