Olin Corporation

Louis C Fiorucci

Michael J Morgan

Michael E Johnson

Kevin M Gregory

A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

Alkali metal nitrate purification

A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

Purification of alkali metal nitrates

A process for producing particles of a non-friable eutectic mixture of sodium nitrate and potassium nitrate for solar power station use is disclosed. In one embodiment of the invention, the particles are produced by shock chilling a molten stream of mixed nitrate material and crushing the resulting flakes to a size range of between about -5 mesh and about +30 mesh. In a second embodiment, particles of this size are produced by spray granulation of a concentrated solution of mixed nitrate salts onto a fluidized bed to produce dry, free-flowing, solid spheres. In both embodiments, the particles are extremely hard, resistant to moisture pickup and adaptable to being readily shipped by bulk containers.

Mixed nitrate salt heat transfer medium and process for providing the

A nonaqueous, in-line method for removing carbonate and hydroxide contamination from a molten mixed sodium nitrate/potassium nitrate heat transfer salt. The method comprises dissolving a stoichiometric quantity of anhydrous Ca(NO.sub.3).sub.2 in the melt whereby an insoluble CaCO.sub.3 and Ca(OH).sub.2 precipitate is formed. The precipitate can be removed by settling, filtration or floatation techniques.

Nonaqueous purification of mixed nitrate heat transfer media

Disclosed is a process for reducing hexavalent chromium [Cr(VI)] in aqueous solutions to trivalent chromium [Cr(III)] by reacting a catalyzed hydrazine composition with the hexavalent chromium at a pH in the range from about 6.0 to about 8.0 to form an aqueous slurry of trivalent chromium compound, said catalyzed hydrazine composition comprising

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Hamden, CT, United States of America

Louis C Fiorucci