Fmc Corporation

John S Chiang

Michael J McCarthy

David Goldstein

Theodore F Munday

Joseph M Ilardi

Charles J Nicholson

William S Moore

The invention is a porous gas diffusion electrode suitable for manufacturing hydrogen peroxide by the reduction of oxygen in an alkaline electrolyte and of a process for fabricating the electrode.

Oxygen gas diffusion electrode

The invention is an electrochemical cell which is useful to reduce oxygen to hydrogen peroxide at a cathode and a process employing the cell. The cell not only avoids the safety hazard of a hydrogen explosion of the prior art cells but also avoids the need for a rigid separating means and cathode.

Process and cell for producing hydrogen peroxide

The invention is an electrochemical cell which is useful to reduce oxygen to hydrogen peroxide at a cathode. The cell avoids the safety hazard of a hydrogen explosion of the prior art cells. The cell has an added advantage in that the dimensions of the cathode are not limited by hydrostatic pressures or by the capacity of the channels and pores of the cathode.

Hydrogen peroxide electrolytic cell

The present invention is a layered article of manufacture or quilt suitable to be useful to construct an electrolytic cell for manufacturing hydrogen peroxide. In use the quilt is placed upon a planar anode and the upper surface contacted with a current collector.

Article for constructing an electrolytic cell

The invention is a method for operating a cell or plurality of cells for manufacturing hydrogen peroxide by reducing oxygen contained in the air. The method comprises directing air free from carbon dioxide over a cathode surface comprising an exterior surface of the cell. The oxygen from the air diffuses into the porous cathode and is reduced to hydrogen peroxide at the surface of an alkaline electrolyte.

Process for manufacturing hydrogen peroxide electrolytically

The invention provides a process to maintain the anolyte pH within a range of 1 pH unit while manufacturing potassium peroxydiphosphate on a commercial scale. The process comprises electrolyzing an alkaline anolyte containing potassium, phosphate, and hydroxyl ions at a platinum or noble metal anode optionally in the presence of a reaction promoter. The catholyte, an alkali metal hydroxide, is separated from the anolyte by at least two separating means, one separating means permeable to either anions or cations, but not both, and the other separating means permeable to an ion excluded by the first separating means.

Electrolytic process for manufacturing potassium peroxydiphosphate

The invention provides a process to maintain the anolyte pH in the desired range while manufacturing potassium peroxydiphosphate on a commercial scale. The process comprises electrolyzing an alkaline anolyte containing potassium, phosphate, and hydroxyl ions at a platinum or noble metal anode optionally in the presence of a reaction promoter. The catholyte, an alkali metal hydroxide, is separated from the anolyte by a separating means permeable to anions permitting hydroxyl ions to be transferred into the anolyte thereby maintaining the pH of the anolyte in the desired range.

The invention provides a process to manufacture fluoride-free potassium peroxydiphosphate on a commercial scale. The process comprises electrolyzing an alkaline anolyte containing potassium, phosphate, nitrate and hydroxyl ions at a platinum or noble metal anode. The catholyte is separated from the anolyte by a separating means permeable to at least one ion contained in the anolyte or catholyte.

Electrolytic process for manufacturing pure potassium peroxydiphosphate

Strontium carbonate is prepared by the process of reacting strontium nitrate in an aqueous reaction medium with carbon dioxide to precipitate strontium carbonate product, the nitric acid byproduct that forms being neutralized by the introduction of lime to the reaction medium.

Preparation of strontium carbonate

A method of spray drying 1-3-8 sodium aluminum phosphate reaction mixtures by the steps:

Method of producing sodium aluminum phosphate

Strontium nitrate is prepared by reacting celestite (strontium sulfate) with excess calcium nitrate in limited amounts of water, quickly extracting strontium nitrate from the reaction mixture by vigorous agitation with additional water, and recovering strontium nitrate by evaporation of the extract solution.

Preparation of strontium nitrate from celestite and calcium nitrate

Organic phosphate solvents used in the extraction of phosphoric acid from impure phosphoric acid solutions, and from which the phosphoric acid has been stripped, are washed with an aqueous alkali orthophosphate solution to remove impurities, particularly silica, fluorine and organic impurities, from the solvent prior to re-use.

Method of regenerating phosphoric acid extraction solvent

In the production of SALP tetrahydrate wherein sodium carbonate and aluminum hydroxide are added to aqueous phosphoric acid, the viscous reactive mixture is agitated with water to free the SALP tetrahydrate crystals from the gelatinous matrix. The crystals are recovered by filtration or centrifugation.

Method of producing crystalline sodium aluminum phosphate

High strength peroxymonosulfate is prepared by adding concentrated sulfuric acid to a solution of a soluble peroxydisulfate whereby the heat of solvation of the sulfuric acid hydrolyzes the peroxydisulfate to the peroxymonosulfate; the temperature is controlled to provide a range of about 140.degree. to 160.degree. F. After about 15 to 45 minutes, the solution is cooled rapidly to about room temperature.

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Mercerville, NJ, United States of America

John S Chiang