Calgon Corporation

Merck + Co., Inc.

Bennett P Boffardi

Paul H Ralston

Leonard J Persinski

Michael M Cook

Jerry L Walker

Susan P Rey

Ann M Sherbondy

Monica A Yorke

Nicholas J Alfano

John P Farkas

Calcium carbonate scale deposits, occurring in gold and silver mining involving the cyanidation process which utilizes heap and vat leaching, and carbon-in-pulp, carbon-in-leach, particularly activated carbon separation columns; said scale deposits forming on the carbon surfaces and in the emitters and sprinklers of the heap leaching system, are controlled using polyether polyamino methylene phosphonates, which provide effective inhibition despite the severe conditions encountered in these systems, including very high pH's.

Scale control in gold and silver mining heap leach and mill water

An orthophosphate salt and sodium silicate, when used in a 3:1 ratio by weight, and in a concentration of 0.1 to 100 mg/L, are found to have a synergistic effect in controlling the corrosion of carbon steel in an aqueous system, e.g., a municipal water supply system. The synergistic combination is also useful in reducing lead solubility and leaching, and in stabilizing soluble iron and manganese and their reaction products.

Synergistic combination of sodium silicate and ortho-phosphate for

Monofluorophosphate salts, especially sodium monofluorophosphate (Na.sub.2 PO.sub.3 F), when added to various industrial water systems in concentrations between 0.1 mg/L and 50 mg/L, significantly reduce the amount of calcium carbonate scale which is formed on heat exchange and other metallic surfaces of such systems. Monofluorophosphate salts, especially sodium monofluorophosphate, when added to various water systems in concentrations between 0.1 mg/L and 50 mg/L also stabilizes soluble manganese ion and its reaction products, i.e., primarily MnO.sub.2, in desirable forms and reduced particle sizes. Monofluorophosphate salts, especially sodium monofluorophosphate, when added to various water systems in concentrations between 1 mg/L and 500 mg/L also stabilizes soluble iron ion and its reaction products, i.e., primarily Fe.sub.2 O.sub.3.

Monofluorophosphate for calcium carbonate scale control and iron and

Synergistic combination of sodium silicate and orthophosphate for

Monofluorophosphate salts, especially sodium monofluorophosphate (Na.sub.2 PO.sub.3 F), when added to potable water sources in concentrations between 0.1 mg/L and 500 mg/L, significantly reduces lead (Pb) leaching into said water, producing the double benefit of reducing lead solubility and thus content in drinking water, while at the same time adding fluoride to that drinking water, with the anticaries benefit that fluoridation provides.

Monofluorophosphate solubility inhibitor for lead in potable water

The instant invention is directed to an admixture, and its use in inhibiting scale and corrosion in aqueous systems, comprising:

Synergistic scale and corrosion inhibiting admixtures containing

A method for inhibiting corrosion in aqueous systems comprising adding to the system being treated an effective amount of a composition comprising a molybdate ion source and a water-soluble component selected from polymaleic acid anhydride, amine adducts of polymaleic anhydride, maleic anhydride copolymers, carboxylic acid/sulfonic acid polymers, salts of the above-described polymers, phosphonates, phosphino carboxylic acids, polyphosphoric acid and esters of polyphosphoric acid.

Method for controlling corrosion using molybdate compositions

A method for stabilizing metal ions in recirculating water systems is disclosed. This method utilizes 2-hydroxyphosphonoacetic acid at a dosage of 0.1-100 ppm to solubilize metal ions thereby reducing deposition and corrosion.

Method for stabilizing metal ions

The present invention is directed to a method to stabilize aluminum ions in recirculating water systems comprising adding to the system 0.1 to 1,000 ppm of a water-soluble polymer having an intrinsic viscosity of 0.05 to 2.5 dl/g in 1.0 M NaCl, prepared from: (A) 35 to 90%, by weight, of an unsaturated carboxylic compound selected from the group consisting of acrylic acid, methacrylic acid, their salts and mixtures thereof; and (B) 10 to 65%, by weight, of an unsaturated sulfonic compound selected from the group consisting of 2-acrylamido-2-methylpropylsulfonic acid, 2-methacrylamido-2-methylpropylsulfonic acid, their salts and mixtures thereof.

Use of carboxylic acid/sulfonic acid copolymers as aluminum ion

The instant invention is directed to a composition useful for inhibiting precipitation of calcium oxalate in aqueous systems comprising: (a) a water soluble phosphate, phosphonate or phosphinate; and (b) a water soluble polyelectrolyte wherein the ratio of component (a) to component (b) ranges from 10:1 to 1:10. The instant invention is further directed to a method of inhibiting the precipitation and deposition of calcium oxalate scale in an aqueous system, comprising adding to said system an effective amount of the above described composition, wherein said aqueous system has a pH greater than or equal to 2.0.

Process for controlling calcium oxalate scale over a wide pH range

A method of inhibiting corrosion of low carbon steel in an aqueous system comprising treating said system with 1.0 to 300 parts per million by weight of the total aqueous content of said system, of a composition comprising aminomethylphosphonic acid compounds and polymaleic anhydride or amine adducts thereof in a weight ratio of from 10:1 to 1:10.

Aminomethylphosphonic acid and polymaleic anhydride combinations for

A method of inhibiting corrosion in an aqueous system comprising treating said system with 1.0 to 300 parts per million by weight of the total aqueous content of said system, of a composition comprising polyphosphate and polymaleic anhydride or amine adducts thereof in a weight ratio of from 10:1 to 1:10.

Polyphosphate and polymaleic anhydride combination for treating corrosion

Use of amino tris(methylene phosphonic acid) and 1-hydroxyethylidene-1,1-diphosphonic acid in a ratio of from about 1:1 to about 3:1 by weight to inhibit corrosion of low carbon steel in aqueous systems.

Corrosion inhibitor

A method of inhibiting corrosion and scale formation in an aqueous system is disclosed which comprises the step of treating the said system with 0.1 to 500 parts per million by weight of the total aqueous content of the said system, of a composition which comprises amine adducts of maleic anhydride polymers and which may additionally include zinc.

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Bethel Park, PA, United States of America

Bennett P Boffardi