Abstract: Purification of aqueous hydrogen peroxide solutions using conventional ion-exchange techniques can result in the hydrogen peroxide decomposing explosively. Much safer processes are obtained by restricting the contact between the resin bed and the hydrogen peroxide solution to a very short contact time, by employing a treatment chamber that is vented to the atmosphere and also by slurrying the resin bed. The bed is conveniently retained on a mesh that acts as a filter (13) preferably conical having an aperture (17) at its apex through which is introduced a small fraction of the solution countercurrent (10) to the main solution flow (9) in order to slurry the bed (19). The solution can be recycled through the same bed or a plurality of beds. Very high purification can be achieved and combined with improved safety of operation.

Abstract: Granules of magnesium salts are obtained by spraying onto agitated feed particles of the salt a small amount of a dilute aqueous solution of a synthetic poly hydroxy-substituted compound, such as polyvinylalcohol, and drying the resultant agglomerate. It is especially suitable to carry out the granulation process in a warm air fluidized bed using feed particles of mainly below 200 microns producing eventually a low bulk density product mainly in the range 200-100 microns. The granular salts have a particle size of from 0.15 to 1.0 mm and a free-flowing bulk density of from 0.3 to 0.6 kg/l.

Abstract: Granules of the magnesium salts of percarboxylic acid carboxylates are obtained by spraying onto agitated feed particles of the salt a small amount of a dilute aqueous solution of a synthetic poly hydroxy-substituted compound, particularly polyvinylalcohol and drying the resultant agglomerate. It is especially suitable to carry out the granulation process in a warm air fluidized bed using feed particles of mainly below 200 microns producing eventually a low bulk density product mainly in the range 200-1000 microns.In a modification of the fluidized bed process, the agglomerating agent used can be a aqueous solution of carboxylated polyvinyl alcohol.

Abstract: Alkali metal or alkaline earth metal peroxides, for example, particularly, calcium peroxide, are produced by recovering a moist peroxide product from an aqueous mixture, formed by reacting hydrogen peroxide and a hydroxide or oxide of the alkali metal or alkaline earth metal, and drying the moist product by means of a pneumatic conveyer drier. The peroxide so produced is suitable for granulation. Alternatively, particulate substances, such as seed, are coated with the peroxide by blending with the moist peroxide product and passing the blend through the pneumatic conveyer drier.