Abstract: Disclosed is a method and apparatus for preventing or minimizing scale deposition from hard water onto heat transfer surfaces in atmospheric cooling towers, such as those used in air conditioning and refrigeration systems, where evaporative cooling of water provides the necessary heat sink to the atmosphere. An electrical/mechanical control system responsive to changes in density of the water in the evaporative cooling system operates to permit discharge of water containing dissolved and suspended solids from the system when its density reaches a predetermined maximum value and to discontinue the discharge of cooling system water when its density reaches a predetermined minimum value. Water drained from the cooling system is replaced by fresh water, preferably by water containing chemical additives to increase solubility of hard water minerals in the cooling water.

Abstract: Disclosed is a method and apparatus for preventing or minimizing scale deposition from hard water onto heat transfer surfaces in atmospheric cooling towers, such as those used in air conditioning and refrigeration systems, where evaporative cooling of water provides the necessary heat sink to the atmosphere. An electrical/mechanical control system responsive to changes in density of the water in the evaporative cooling system operates to permit discharge of water containing dissolved and suspended solids from the system when its density reaches a predetermined maximum value and to discontinue the discharge of cooling system water when its density reaches a predetermined minimum value. Water drained from the cooling system is replaced by fresh water, preferably by water containing chemical additives to increase solubility of hard water minerals in the cooling water.

Abstract: A method for removal of scale from heat transfer equipment in which the scale contaminated surface is first contacted with a cleaning composition consisting essentially of an aqueous solution of hydroxyacetic acid and a polysaccharide gum and then contacted with a dilute aqueous solution of citric acid.

Abstract: Disclosed is a method and apparatus for preventing or minimizing scale deposition from hard water onto heat transfer surfaces in atmospheric cooling towers, such as those used in air conditioning and refrigeration systems, where evaporative cooling of water provides the necessary heat sink to the atmosphere. An electrical/mechanical control system responsive to changes in density of the water in the evaporative cooling system operates to permit discharge of water containing dissolved and suspended solids from the system when its density reaches a predetermined maximum value and to discontinue the discharge of cooling system water when its density reaches a predetermined minimum value. Water drained from the cooling system is replaced by fresh water, preferably by water containing chemical additives to increase solubility of hard water minerals in the cooling water.

Abstract: This invention relates to a method of beneficiating coal or mineral ores containing a metaliferous sulfide, e.g. iron sulfide or pyrite, and comprises removal of unwanted components, including pyrite, from such ores by subjecting an aqueous pulp of the pulverized mineral or coal to a froth flotation process in which pyrites are depressed by a depressant composition comprising xanthan gum, a hydroxycarboxylic acid and sodium silicate. The process is especially useful for removal of pyrite from a solid carbonaceous fuel, e.g., coal containing pyrite, and for the recovery of non-ferrous metal concentrates from ores containing pyrite. The coal or ore may be subjected to a mild preoxidation treatment to enhance sulfide removal in the subsequent froth flotation operation.

Abstract: The present invention is directed to a composition which includes an aliphatic alpha-hydroxy carboxylic acid, a gum or polymeric thickener which is soluble in water at a pH of about 3 or less and optionally sodium silicate. The composition may be employed in removing scale from a surface.

Abstract: The present invention is directed to a composition which includes an anionic fatty alcohol metal sulfate surfactant, a nonionic substituted poly (ethylene oxide) surfactant, an ethanolamine, zinc and hydroxyacetic acid. A method for removing scale from a surface is taught.