A composition for treating an inorganic slurry, the composition including: (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, the phosphonated compound being a tetra sodium salt of nitrilo-tris(methylene phosphonate) and (ii) a homopolymer of an unsaturated acid, the homopolymer being a homopolymer of acrylic acid having a molecular weight in the range of 2,000 to 5,000.
