Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting out agent, conventionally sodium chloride. The invention provides a process intended to be conducted without addition of chloride salting-out agent in which the dissolution step is controlled to restrict the sodium carbonate concentration to below 95%, preferably 60 to 90% of its saturated concentration at a temperature preferably controlled to at most 35C. and the mole ratio of hydrogen peroxide:sodium carbonate in the reaction vessel is controlled to between 0.7 to 1.2:1, and preferably about 1:1.

Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting out agent, conventionally sodium chloride.

Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting-out agent, conventionally sodium chloride. The invention provides a process intended to be conducted without addition of chloride salting-out agent in which the dissolution step (1) is controlled to restrict the sodium carbonate concentration to below 95%; preferably 60 to 90% of its saturated concentration at a temperature preferably controlled to at most 35° C. and the mole ratio of hydrogen peroxide: sodium carbonate in the reaction vessel is controlled to between 0.7 to 1.2:1, and preferably about 1:1.

Abstract: Process for obtaining aqueous hydrogen peroxide solutions by the alkylanthraquinone process, providing a concentrated aqueous hydrogen peroxide solution with a low content of impurities, according to which a continuous addition of acidifying compounds and/or of stabilising compounds is performed, consisting in recycling towards the oxidation unit at least a part of the purge leaving the distillation unit.

Abstract: Process for obtaining purified hydrogen peroxide solutions, consisting in evaporating the crude aqueous hydrogen peroxide solution containing the impurities and feeding by means of the vapour phase produced the foot of a distillation column provided in its lower part with a zone for washing the vapour phase with a small flow of liquid which refluxes in the bottom of the column and which has the same composition as the purified aqueous hydrogen peroxide solution forming the product leaving the column, in drawing off this purified product at a column height such that the draw-off is carried out above the vapour phase washing zone and in collecting at the bottom of the column a residue consisting of the small flow of washing liquid which contains most of the impurities. The washing zone has a diameter which is greater than that of the remainder of the column.Distillation column for carrying out the process.

Abstract: Electrolyser for the production of a gas, comprising a stack of vertical frames (1, 2) defining electrolysis chambers (4, 5), a degassing chamber (17) above the stack, a conduit for allowing electrolyte to enter (23) the degassing chamber, a vertical pipe (18) connecting the degassing chamber to the lower part of the electrolysis chambers and a nozzle (20) arranged around the pipe and connecting the degassing chamber to the upper part of the electrolysis chambers, the pipe (18) communicating with the degassing chamber (17) through a connecting conduit (19, 21) passing through the nozzle (20).