Produits Chimiques Ugine Kuhlmann

Paul Mollard

Louis Mesaros

Pierre Lakodey

A sodium perborate (NaBO.sub.2, H.sub.2 O.sub.2, 3H.sub.2 O) product having approximately spherical particles of size between about 250 and 600 microns, a bulk density between about 0.75 and 1.05 Kg./liter and a superior resistance to abrasion and impact, is prepared by a method comprising crystallization from a supersaturated aqueous solution of sodium perborate in the presence of an anionic surfactant and in the absence of alkaline metal silicates.

High-density sodium perborate and method of preparation

Improved processes for preparing sodium percarbonate, 2Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2, which can have an apparent density of 0.6 to 1 g/cm.sup.3 and a mean particle diameter of 210 to 610 microns, which processes comprise treating a sodium carbonate monohydrate or hydrate having 75 to 90% of Na.sub.2 CO.sub.3 and having a density equal to or even greater than 1.2 g/cm.sup.3 with 60 to 80% aqueous hydrogen peroxide, the reaction mixture containing a small quantity of nonionic surfactant stable in hydrogen peroxide and alkaline solutions, the percarbonate formed being well adapted for use in detergent compositions.

Processes for preparing sodium percarbonate

Sodium Chlorite is made stable under storage conditions by (1) admixing with the sodium chlorite a stabilizing salt chemically inert to sodium chlorite and having at least one hydrate whose melting point is higher than about 50.degree. C, in amount such that said stabilizing salt can capture a quantity of water equal to at least about 5% of the weight of the sodium chlorite (NaClO.sub.2), the weight of the water in the total mixture being at least about 5% of the weight of said sodium chlorite and (2) drying the mixture sufficiently to reduce the water not captured by the stabilizing salt to an amount equal approximately to zero. Sodium chlorite thus stabilized is thermally stable and does not congeal into a solid mass even when stored in drums for several months at 50.degree. C.

Storage-stable sodium chlorite

Processes for the preparation of sodium percarbonate having substantially the formula 2Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2, the processes being particularly suited to the use of ordinary sodium carbonate, which processes comprise reacting 60 to 80 percent hydrogen peroxide with sodium carbonate monohydrate or a hydrate of sodium carbonate containing from about 75 to 90 percent sodium carbonate; and products obtained thereby, particularly those percarbonate products having an excellent resistance to shock and attrition and effective densities of 0.61-0.92 g/cm.sup.3 and mean particle diameters of 250-610 microns.

Process for the production of sodium percarbonate

Processes for the preparation of alkali metal percarbonate which comprise separately spraying into a reaction chamber a hot aqueous solution of sodium hydroxide and an aqueous solution of hydrogen peroxide and introducing a hot gas containing air and carbon dioxide to obtain sodium percarbonate, the product having a mean particle diameter between 0.1 and 0.5 mm, an apparent density between 0.2 and 1 g/cm.sup.3, and an active oxygen content between 7 and 15.3 percent, the sodium percarbonate being particularly adapted for use in domestic laundry products.

Process for the production of sodium percarbonate by atomization

A method for preparing sodium chlorate comprises electrolyzing aqueous sodium chloride in the presence of at least one phosphorus-containing agent for complexing alkaline earth impurities, thereby advantageously extending the periods of uninterrupted satisfactory cell operation at substantially constant applied potential and facilitating the cleaning of electrodes between such periods.

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Sainte Foy Les Lyon, France

Paul Mollard