Flocculant behaviour with coal—Shale slurries

Polymer flocculants, whilst having a proven ability as settling and filtration aids, are relatively expensive additives and must therefore be selected and applied with careful consideration.When it appears possible to make reliable prediction of dosage requirement based upon some specific understanding of flocculant behaviour with a particular material, then such a prediction may further reduce the risk of incorrect selection and administration.This paper describes recent work conducted to examine the behaviour of coal slurries varying in ash content, when flocculated with a number of different flocculants. The objective of the work was to determine whether any common relationship existed between flocculant dosage requirement, and the proportions of coal-shale present in the slurry. However, the paper has been written not as an attempt to prescribe specific flocculant types but rather, to provide an indication of what is considered by the author as being a realistic approach towards the assessment of flocculant suitability for a particular mixture of coal and shale.