Particles of stabilized peroxygenated compounds, process for their manufacture, and composition containing such particles

Process for the manufacture of particles comprising at least one stabilised peroxygenated compound which is selected from the group consisting of the normally relatively unstable persalts of alkali metals comprising introducing an aqueous solution containing hydrogen peroxide and an aqueous solution containing the salt corresponding to said persalt continuously into a fluidised bed drier, feeding the fluidised bed drier continuously with seeds whose dimensions are less than those of the particles which it is desired to obtain, and evaporating the water present in said aqueous solutions continuously in the drier by means of the fluidisation gas, wherein a stabilizer for the peroxygenated compound is simultaneously introduced into the fluidised bed drier, said stabilizer being a polymer which possesses hydroxyl groups and carboxyl groups, or its percursor, said polymer containing monomeric units of the formula ##STR10## where R.sub.1 and R.sub.2 represent hydrogen or an alkyl group containing from 1 to 3 carbon atoms and where M represents hydrogen, an alkali metal atom or an alkaline earth metal atom M-.