Patent ID: 8772356

Claim:
A method for treating an inorganic slurry to preserve the slurry against bacterial contamination, comprising the steps of: (I) providing a slurry in a substantially homogeneous phase, and then (II) adding to said slurry an effective amount of a composition comprising: (a) a tetrakis(hydroxyorgano)phosphonium salt selected from the group consisting of tetrakis(hydroxymethyl)phosphonium sulphate, tetrakis(hydroxymethyl)phosphonium chloride, tetrakis(hydroxymethyl)phosphonium phosphate, tetrakis(hydroxymethyl)phosphonium nitrate and tetrakis(hydroxymethyl)phosphonium oxalate; and (b) a dispersant selected from the group consisting of (b)(i) a sodium salt of nitrilo-tris(methylene phosphonate) and (b)(ii) a homopolymer of acrylic acid having a molecular weight in the range of 2,000 to 5,000; and (III) preserving the slurry against bacterial contamination, whilst avoiding instantaneous heterogeneous thickening of the slurry due to the tetrakis(hydroxyorgano)phosphonium salt.