Abstract: A process is described for removing mineral or ash constituents from heavy hydrocarbon residues, such as those resulting from coal-oil coprocessing, residue hydrocracking or coal liquifaction. The process comprises the steps of: (a) intimately mixing the ash-containing heavy hydrocarbon oil residue with a surfactant and a pH-conditioned aqueous solution under high shear mixing conditions to disperse the ash-containing residue in the aqueous phase thereby creating a fine oil-in-water emulsion, (b) adding a strong oxidizing agent to the emulsion to thereby break the emulsion and release the ash into the aqueous phase and (c) separating the ash-containing aqueous phase from the oil phase. The HLB method for characterizing the emulsion forming activity of a surface active material is described in M. J. Rosen, Surfactants and Interfacial Phenomena, John Wiley & Sons, New York (1989), incorporated herein by reference.