Abstract: Process for bleaching a chemical paper pulp to a brightness of at least 89° ISO, consisting in subjecting the pulp to a treatment sequence of several stages including a final bleaching stage with hydrogen peroxide in alkaline medium carried out in the presence of at least one stabilising agent and at a consistency of at least 25% by weight of solids, the stages preceding this final stage having purified the pulp so that its manganese content does not exceed 3 ppm by weight with respect to the solids and that the pulp has been delignified beforehand to a kappa number not exceeding 5.

Abstract: Process for preserving the mechanical strength properties of a chemical paper pulp, comprising two treatment stages by means of a peroxidic reagent, with the first stage in an acidic medium and the second stage in an alkaline medium, according to which a treatment by means of a reducing compound is interposed between the two stages.

Abstract: Process for stabilizing solutions of peroxidic compounds used for bleaching. At least one polymer derived from an alpha-hydroxyacrylic acid, which contains units of the formula ##STR1## where R.sub.1 and R.sub.2 represent hydrogen or an alkyl group comprising from 1 to 3 carbon atoms which can be substituted by a hydroxyl group or a halogen atom, R.sub.1 and R.sub.2 being identical or different, and where M represents an alkali metal atom, a hydrogen atom or an ammonium group, is added to the solution as a stabilizer.

Abstract: A process for the reclamation of waste paper in the presence of an aqueous alkaline solution comprises having the solution contain at least a carboxylated polymer.