Abstract: Process for improving retention during the manufacture of paper, board or the like, which consists:first of all in adding to the fibrous suspension a first retaining agent formed by a cationic polymer of high molecular weight,then, optionally in shearing the flocs obtained,and finally, in adding to the suspension a second retaining agent of inorganic nature, characterized in that the second retaining agent is a kaolin pigment.

Abstract: A process for preparing stable emulsions of polyelectrolytes of high molecular weight as reverse emulsion, in which:the monomers are dissolved in an aqueous phase,an organic phase containing a surface-active agent is prepared,these two phases are mixed to obtain an emulsion of the water-in-oil (W/O) type,the monomers are polymerized,the emulsion is incorporated to obtain a water-in-oil (W/O) emulsion, so as to make the polyacrylamide obtained water-soluble, which consists in adding to the aqueous phase a soluble polymer of low molecular weight, of the same general chemical nature and of the same ionic nature as the polyelectrolyte of high molecular weight which is envisaged.Envisaged application: preparation of polyacrylamide for flocculation and/or thickening applications (urban and industrial water treatments, papermaking).

Abstract: Improved process for fluidifying flocculated aqueous suspensions of red muds in the production of alumina from bauxite by the Bayer process, which consists:in dissolving bauxite using sodium hydroxide;then, in decanting and in washing the red muds formed in order to separate them from the alumina in successive vats, while recycling the washing waters upstream;and finally, in eliminating the red muds thus treated;and in which a flocculant (F) consisting of a polyacrylamide of molecular weight greater than ten million is introduced into the suspension of one of the successive vats;wherein a dispersing agent (D) formed by an anionic acrylic acid polymer of molecular weight lower than fifty thousand is added simultaneously with said flocculant (F) to the suspension in the same vat.

Abstract: Process for the manufacture of a paper or a cardboard having improved retention, in which a polyacrylamide and bentonite are added to the fibrous suspension, wherein in that the polyacrylamide is a branched polyacrylamide, which is easily soluble in water, and is introduced in the dissolved powder form at a concentration of 0.03 to 1.0 per thousand (0.03 to 1.0%) by weight of the dry weight of the fibrous suspension.

Abstract: The device is composed of a conical section located on the edge of the disk rim. The greatest radius of the conical section is at least equal to the radius of the circumference passing through the bottom of the axial grooves into which the blade roots are inserted. A groove is formed in the end of the lower part of the root, this groove having a right angle triangular section. A locking part has one face pressed against the bearing and two other faces against the sides of the groove in the root. A blade extending longitudinally in the locking part works together with a groove in the slot of the blade root to keep the locking part in place.