A composition for treating an inorganic slurry, the composition comprising: (a) a tetrakis (hydroxyorgano) phosphonium salt and (b) a dispersant selected from the group consisting of (i) a phosphonated compound containing at least one tertiary nitrogen atom, (ii) a phosphonated oligomer of an unsaturated acid, (iii) a homopolymer of an unsaturated acid, and (iv) a polyphosphate.
