Rust and scale removal composition and process

A rust and/or scale removal composition comprising an aqueous dispersion of solids in water wherein said composition consists essentially of:

• I) from about 0.1 to about 40 weight percent solids;
• and
• II) from about 60 to about 99.9 weight percent water;
• wherein said solids comprise:
• a) from about 30 to about 95 weight percent of an inorganic reducing agent;
• b) from about 1 to about 50 weight percent of a chelating agent;
• c) from about 0.05 to about 5 weight percent of a low foam penetrating surfactant;
• d) from about 1 to about 30 weight percent of a water soluble polymeric dispersant;
• and
• e) from about 0.5 and about 5 weight percent of a hydrotrope selected from the group consisting of phosphate esters, phosphated alcohol ethoxylate, phosphated linear alcohol, and phosphated alkylphenol ethoxylate.

A process for removing rust and/or scale from an aqueous system comprising treating said aqueous system with from about 10 ppm to about 90% of the total fluid in the system of a rust and/or scale removal composition comprising an aqueous dispersion of solids in water wherein said composition consists essentially of:

• I) from about 0.1 to about 40 weight percent solids;
• and
• II) from about 60 to about 99.9 weight percent water;
• wherein said solids comprise:
• a) from about 30 to about 95 weight percent of an inorganic reducing agent;
• b) from about 1 to about 50 weight percent of a chelating agent;
• c) from about 0.05 to about 5 weight percent of a low foam penetrating surfactant;
• d) from about 1 to about 30 weight percent of a water soluble polymeric dispersant selected from the group consisting of copolymers and terpolymers of acrylic acid/3-acrylamido, 2-methyl propyl sulfonic acid;
• acrylic acid/sulfonated styrene;
• and acrylic acid sulfophenoxy methallyl ether/maleic acid, and salts thereof, and wherein said water soluble polymeric dispersant has a weight average molecular weight ranging from about 500 to about 25,000.

A process for removing rust and/or scale from an aqueous system comprising treating said aqueous system with from about 10 ppm to about 90% of the total fluid in the system of a rust and/or scale removal composition comprising an aqueous dispersion of solids in water wherein said composition consists essentially of:

• I) from about 0.1 to about 40 weight percent solids;
• and
• II) from about 60 to about 99.9 weight percent water;
• wherein said solids comprise:
• a) from about 30 to about 95 weight percent of an inorganic reducing agent;
• b) from about 1 to about 50 weight percent of a chelating agent;
• c) from about 0.05 to about 5 weight percent of a low foam penetrating surfactant;
• d) from about 1 to about 30 weight percent of a water soluble polymeric dispersant;
• and
• e) from about 0.5 and about 5 weight percent of a hydrotrope selected from the group consisting of phosphate esters, phosphated alcohol ethoxylate, phosphated linear alcohol, and phosphated alkylphenol ethoxylated.