Abstract: Process for removing an industrial residue containing sodium sulphate, in which the sodium sulphate in the residue 7 is treated with a calcium salt 12 to precipitate calcium sulphate 13, which is sent to a rock salt deposit 15, from which an aqueous solution of sodium chloride 16 is withdrawn.The process applies to the residues from the desulphurization of fumes by means of sodium bicarbonate.

Abstract: Substituted thiophenes of the general formula: ##STR1## in which: R represents a hydrogen atom, a halogen atom or an aliphatic group containing from 1 to 4 carbon atoms,X represents a hydrogen atom or a fluorine atom,Y represents an at least partially fluorinated aliphatic or aromatic group,m represents an integer equal to or greater than 2, andn represents an integer such that 0.ltoreq.n.ltoreq.7.The invention also relates to the electrically conducting polymers containing recurring units derived from monomers chosen from the substituted thiophenes.

Abstract: A mixture is produced, comprising from 50 to 95% by weight of at least one vinyl chloride-based resin, from 1 to 20% by weight of at least one olefin-based resin, from 1 to 20% by weight of a copolymer of ethylene and vinyl acetate which has a vinyl acetate content of between 10 and 35% and from 2 to 40% by weight of a copolymer of ethylene and vinyl acetate which has a vinyl acetate content of between 60 and 95%, and the product thus obtained is then processed.The process makes it possible in particular to produce sheets which have good mechanical properties and which have a remarkable transparency.

Abstract: The winder comprises a central driving carrier tube (1) and winding drums (2) equipped with self-blocking systems (3) for receiving reeling mandrils (4) arranged successively round the central driving carrier tube, the said drums (2) each being connected to this tube by means of a magnetic coupling (16), (17), (18) located inside the said tube (1) and connected, on the one hand, rigidly to this tube (1) and, on the other hand, to the drum (2), in said winder the connection between the magnetic coupling (16), (17), (18) and the drum (2) being made via a speed multiplier (6), (6'), (6"), (13) likewise arranged in the central driving carrier tube (1). The winder allows a reeling of a series of widths cut from the web material, this being carried out with controlled winding tensions.

Abstract: The invention relates to a solution for dialysis containing a derivative of 3-hydroxybutanoic acid chosen from oligomers of this acid and esters of this acid or of these oligomers with 1,3-butanediol.

Abstract: Process for the preparation of .beta.-hydroxybutyric acid esters, comprising:1) a step involving alcoholysis of the polyhydroxybutyrate in the presence of an alcohol, a halogenated solvent, and an acid,2) a neutralization step comprising the addition of an alcoholate in solution in the alcohol,3) a purification step comprising the addition of a halogenated solvent and the azeotropic removal of water and the alcohol,4) a step for recovery of the ester, comprising a filtration, a distillation of the halogenated solvent and a distillation of the ester.This process enables .beta.-hydroxybutyric acid esters of high purity to be obtained.

Abstract: Baths for chemical polishing of copper or copper alloy surfaces, comprising, in aqueous solution, hydrogen peroxide, phosphoric acid and tetraborate ions.

Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non-oxidizing one, leading to an activated catalyst. A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: The invention relates to catalytic compositions for the hydrogenation of chlorofluoroalkenes to fluoroalkenes, comprising a porous carrier impregnated with metal of group VIII of the Periodic Table of the elements and with one or more compounds chosen from the salts of an alkali metal or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: The device which is used for recovering a fusible core employed for moulding a hollow plastic article includes a bath of a liquid heated to a temperature at least equal to the melting temperature of the metal constituting the fusible core, a handling mechanism for introducing and holding the hollow article in this bath and a mechanism for heating, using electrical induction, the fusible core of the hollow article, the liquid bath being contained in a leakproof enclosure (1) made of an electrically nonconductive material which withstands the temperature of the bath and the mechanism of heating using electrical induction (4) being arranged outside and around the enclosure (1).

Abstract: Process for the purification of an aqueous alkali metal chloride solution from iodine compounds and ammonium compounds, in which the operation is carried out in two successive stages comprising a first stage in which the iodine compounds are oxidized to molecular iodine which is removed from the solution on a halogenated basic anion exchange resin, and a second stage in which the ammonium compounds are oxidized to form nitrogen which is removed in a stream of inert gas.

Abstract: Process for preparing a latex of polypyrrole in an aqueous reagent medium containing a ferric salt, a hydrolyzed polyvinyl acetate and a dodecyl sulphate.The films prepared with this conducting latex are homogeneous, adhere to metals and metallized glasses and have high conductivity.

Abstract: Process for the removal from vinyl chloride of compounds of the ester type by an operation of treatment comprising an alkaline washing and a treatment with a bisulphite.

Abstract: The invention relates to catalytic compositions for the hydrogenation of 1,1,2-trichloro-1,2,2-trifluoroethane to chlorotrifluoroethylene and trifluoroethylene comprising a porous oxygenated support impregnated with a metal of group VIII of the periodic table of the elements and one or more compounds chosen from the salts of an alkali or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: The present invention relates to a process for the treatment of heavy residues produced in the manufacture of chlorinated products, in which process a chemical compound chosen from certain fatty compounds is added to the heavy residues in order to form fluid and stable liquid suspensions.

Abstract: The invention concerns:a catalytic solid containing magnesium, a halogen, titanium and silicon, this catalytic solid also containing aluminium and being microporous;a process for preparing this catalytic solid;use of this catalytic solid for polymerizing alpha-olefines.

Abstract: Article made of lactic acid polymer capable of being employed particulaly as a biodegradable prosthesis exhibiting at 23.degree. C. a tensile regidity modulus higher than 5000 MPa and a tensile resilience higher than 500 kJ/m.sup.2 and a heat shrinkage of less than 50% at 130.degree. C.The article is produced by forging a blank at a temperature of between 80.degree. and 170.degree. C., with a draw ratio of 200 to 1000%.

Abstract: Compositions based on vinylidene fluoride polymers, which have a reduced smoke-producing capacity, comprising, as smoke-reducing agent, an effective amount of a dialkyltin dicarboxylate.The compositions are very particularly suitable for the manufacture of shaped articles in the building and the aeronautical industries.

Abstract: In a first stage, a lactone is polymerized by an ionic route in vinyl chloride with the aid of a catalyst consisting of the product, optionally complexed with tetrahydrofuran, of the reaction of an alkylmetal with ethylenically unsaturated alcohol, optionally in the presence of water and, in a second stage, the said vinyl chloride is polymerized by a radical route in an aqueous suspension and in the presence of the polymerization medium originating from the first stage, to which other unsaturated monomers are optionally added.The invention also relates to new modified vinyl chloride polymers consisting of lactone polymers whose number-average molecular weight is less than 5,000, grafted with vinyl chloride polymers.

Abstract: Process for the manufacture of alkali metal sulphide, in which an electrolysis cell is used in which a membrane which is selectively permeable to cations separates an anode chamber containing an anode from a cathode chamber containing a cathode, an electrolyte containing alkali metal is electrolyzed in the anode chamber and an aqueous solution of alkali metal polysulphide is electrolyzed simultaneously in the cathode chamber.