Journal article

Production of Ultra Clean Coal Part II - Ionic equilibria in solution when mineral matter from black coal is treated with aqueous hydrofluoric acid

KM Steel, J Besida, TA O'Donnell, DG Wood

FUEL PROCESSING TECHNOLOGY | ELSEVIER SCIENCE BV | Published : 2001

Abstract

A model for determination of the concentration of fluoride complexed aluminium and silicon species, free fluoride (F-), H+ ions and molecular HF in solution when aluminosilicate compounds are treated with aqueous HF is presented. The model elucidates chemical mechanisms governing both the dissolution behaviour of the mineral matter in coal towards aqueous HF, and the unwanted precipitation of various fluoride compounds, such as CaF2, MgF2 and NaAlF4. The controlling parameter for the precipitation of fluoride compounds is the free F- concentration in solution. The model has application toward the development of chemical strategies for dissolving virtually all of the mineral matter from coal ..

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University of Melbourne Researchers