A composition comprising: (a) tetrakis(hydroxymethyl)phosphonium sulfate (THPS); (b) water; and (c) methanol; wherein the weight percentages of (a), (b) and (c) are within the area on a ternary phase diagram for (a), (b) and (c) bounded by four points: (A) 5% THPS/58% water/37% methanol; (B) 5% THPS/36% water/59% methanol; (C) 65% THPS/27% water/8% methanol; and (D) 65% THPS/29% water/6% methanol.

A composition comprising: (a) tetrakis(hydroxymethyl)phosphonium sulfate (THPS); (b) water; and (c) 1,2-propanediol; wherein the weight percentages of (a), (b) and (c) are within the area on a ternary phase diagram for (a), (b) and (c) bounded by five points: (A) 20% THPS/40% water/40% 1,2-propanediol; (B) 20% THPS/20% water/60% 1,2-propanediol; (C) 65% THPS/22% water/13% 1,2-propanediol; (D) 65% THPS/25% water/10% 1,2-propanediol; and (E) 40% THPS/28% water/32% 1,2-propanediol.

A composition comprising: (a) tetrakis(hydroxymethyl)phosphonium sulfate (THPS); (b) water; and (c) 1,2-propanediol; wherein the weight percentages of (a), (b) and (c) are within the area on a ternary phase diagram for (a), (b) and (c) bounded by five points: (A) 20% THPS/40% water/40% 1,2-propanediol; (B) 20% THPS/20% water/60% 1,2-propanediol; (C) 65% THPS/22% water/13% 1,2-propanediol; (D) 65% THPS/25% water/10% 1,2-propanediol; and (E) 40% THPS/28% water/32% 1,2-propanediol.

A composition comprising: (a) tetrakis(hydroxymethyl)phosphonium sulfate (THPS); (b) water; and (c) 1,2-propanediol; wherein the weight percentages of (a), (b) and (c) are within the area on a ternary phase diagram for (a), (b) and (c) bounded by five points: (A) 20% THPS/40% water/40% 1,2-propanediol; (B) 20% THPS/20% water/60% 1,2-propanediol; (C) 65% THPS/22% water/13% 1,2-propanediol; (D) 65% THPS/25% water/10% 1,2-propanediol; and (E) 40% THPS/28% water/32% 1,2-propanediol.

A synergistic antimicrobial composition having two components. The first component is a hydroxymethyl-substituted phosphorus compound. The second component is one of the following biocides: hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine, 2,6-dimethyl-1,3-dioxan-4-yl acetate or ortho-phenylphenol or its alkali metal or ammonium salts.

A synergistic antimicrobial composition having two components. The first component is a hydroxymethyl-substituted phosphorus compound. The second component is one of the following biocides: hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine, 2,6-dimethyl-1,3-dioxan-4-yl acetate or ortho-phenylphenol or its alkali metal or ammonium salts.

A synergistic antimicrobial composition having two components. The first component is a hydroxymethyl-substituted phosphorus compound. The second component is one of the following biocides: hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine, 2,6-dimethyl-1,3-dioxan-4-yl acetate or ortho-phenylphenol or its alkali metal or ammonium salts.

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.

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.

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.