Abstract: A diaphragm is disclosed for molten salt bath electrolysis of metal halides, the diaphragm comprising carbon fibers disposed in one plane an in at least one direction, embedded at least partially in a rigid and inert material which can be graphite, carbides, oxides or nitrides. The diaphragm has a porosity between 10% and 60% in the form of apertures of an area between 1 and 50 mm.sup.2.

Abstract: The invention relates to a process and apparatus for the pumping and metering of liquid products, wherein the melting point is between 200.degree. and 350.degree. C. In the process, a pulsation generator with piston and diaphragm displaces a thermal fluid which actuates a pumping apparatus, and the fluid transmits its pulsations to a molten tin alloy or tin bath contained in a siphon, the bath in turn transmitting the pulsations to part of the liquid product to be displaced and which is contained in a conduit connecting the siphon to a diaphragm-free pumping head, between the suction valve and delivery valve of the said pumping head, which makes the latter operate in suction and delivery with respect to the same product between suction pipe and delivery pipe. The process and apparatus are particularly applicable to the pumping of melted salts with a melting point between 200.degree. and 350.degree. C. at temperatures between 210.degree. and 380.degree. C.

Abstract: The invention relates to a process and apparatus for the supply of a Kroll reactor with zirconium tetrachloride vapor, in which zirconium chloride powder is vaporized in a sublimator by heating power and the vapor obtained is passed into the reactor. Part of the heating power applied in the sublimator is supplied to the powder by an internal heating means, and the remainder of the heating power is supplied to the wall of the sublimator by an external heating means. The heating power of the internal heating means is used for the sublimation of the zirconium tetrachloride powder and the heating power of the external means is applied in order to compensate the heat losses of the wall of the sublimator.

Abstract: The process and the device according to the invention relate to the introduction, at a stable, known flow rate, of sublimable tetrachloride into a column for continuous extractive distillation under pressure of the chlorides. The sublimable tetrachloride is dissolved in a hot dissolver in a liquid solvent such as KAlCl.sub.4, and is then recirculated by pump at a stable, known flow rate into an evaporator connected to the column. The solution is then heated in an evaporator in order to sublime the majority of the product which it contains, the sublimed vapors thus passing into the column at a stable, known flow rate. The process according to the invention is adapted, in particular, to a plant for the production of ArCl.sub.4 of nulear purity and of HfCl.sub.4.

Abstract: The invention concerns a process for the production of metal Zr by means of molten Mg in a reactor 1 having a hearth plate 3, comprising separating the magnesium chloride formed in the reduction reaction from the metal Zr formed. The process is characterized by separating the magnesium chloride formed by tapping off towards the bottom of the reactor 1 by means of a chimney 6 whose bottom end portion 5 is fixed to an orifice 4 in the hearth plate 3 and whose transverse open top end 7 is above the portion of the metallic mass Zr, Mg which borders the chimney 6 at the end of the reduction reaction. The invention also concerns the corresponding apparatus for the production of metal zirconium. The invention provides a simplification in the operation of separating the MgCl.sub.2 formed and possibly, by virtue of a particular structure of the chimney according to the invention, gives an improvement in the operation of extracting the sponge cake produced.

Abstract: The invention concerns a process and an apparatus for maintaining a very thin film in an exchanger involving a flowing liquid film. The process wherein the liquid films are fed by gravity from a liquid source is characterised in that: each film is fed at the permanent flow (kd.sub.1) corresponding to the feed flow rate (d.sub.1) of the source; then for a short period of time the flow rate is increased to a transient value (kd.sub.2) for establishing a continuous film over the whole of the corresponding flow surface; then operation returns to the flow rate (kd.sub.1) for the film in question, the short periods of feeding the different films at their transient flow rates (kd.sub.2) being displaced in respect of time. The apparatus according to the invention comprises at the top of each flow tube a movable sleeve, lifting movement or rotary movement of which opens a supplementary communication between the liquid source and the tube, permitting the film flow rate to assume the transient value (kd.sub.2).

Abstract: The invention concerns a process for the production of metal Zr by means of molten Mg in a reactor (1) having a hearth plate (3), comprising separating the magnesium chloride formed in the reduction reaction from the metal Zr formed and the magnesium, then cooling, then extracting the sponge cake of metal Zr formed. The process is characterized by separating the magnesium chloride formed by tapping off towards the bottom of the reactor (1) by means of a chimney (6) whose bottom end portion (5) is fixed to an orifice (4) in the hearth plate (3) and whose transverse open top end (7) is above the portion of the metallic mass (Zr, Mg) which borders the chimney (6) at the end of the reduction reaction.The invention also concerns the corresponding apparatus for the production of metal zirconium.The invention provides a simplification in the operation of separating the MgCl.sub.

Abstract: The invention relates to a process for the separation of zirconium, and hafnium tetrachlorides from mixtures thereof. The process according to the invention consists of selectively absorbing zirconium tetrachloride and hafnium tetrachloride vapors in a solvent medium circulating counter-current to these vapors in a distillation column, wherein the solvent consists of a molten chloroaluminate and/or chloroferrate of potassium. The process described may be used to obtain hafnium-free zirconium tetrachloride which may then be used to prepare nuclear-grade zirconium, and hafnium tetrachloride containing little zirconium.

Abstract: The invention relates to a process for separating mixtures of hydrocarbons, notably conjugated diene hydrocarbons or aromatic hydrocarbons, from mixtures containing the same, by the general technique of permeation or pervaporation through specific membranes.The specific membranes used are formed of a high polymer comprising functional groups chemically combined by covalent bonding within the polymer forming the said membrane, the said groups possessing a physicochemical affinity, notably a capacity to complex, with respect to one of said hydrocarbons and, substantially, the absence of such a capacity with respect to other hydrocarbons of the mixture. For the separation of dienes, such as butadiene and pentadiene, membranes are used containing active nitrile, pyrrolidone, N-substituted groups, such as N-alkyl groups, preferably N-vinyl or N-methyl-pyrrolidone. The membrane can be obtained, for example, by copolymerization of butadiene with acrylonitrile, with the membrane containing about 2.