Abstract: The invention relates to a process for manufacturing an oxychloride or oxide of actinide(s) and/or of lanthanide(s) from a chloride of actinide(s) and/or of lanthanide(s) present in a medium comprising at least one molten salt of chloride type comprising a step of bringing said chloride of actinide(s) and/or lanthanide(s) present in said medium comprising at least one molten salt of chloride type into contact with a wet inert gas.

Abstract: The invention relates to a process for manufacturing an oxychloride or oxide of actinide(s) and/or of lanthanide(s) from a chloride of actinide(s) and/or of lanthanide(s) present in a medium comprising at least one molten salt of chloride type comprising a step of bringing said chloride of actinide(s) and/or lanthanide(s) present in said medium comprising at least one molten salt of chloride type into contact with a wet inert gas.

Abstract: A method of separating zirconium and hafnium tetrachlorides using a solvent comprising firstly an alkaline metallic solvent comprising a salt made up of an alkali metal chloride and an acidic metal chloride A, for example a chloroaluminate or an alkaline chloroferrate, and secondly an acidic metal or metalloid chloride B of acidity that is less than that of the acidic metal chloride A. The acidic metal or metalloid chloride B may be selected from chlorides of Mg, Zn, and Cu. The method may be a continuous separation method by selective absorption of the tetrachloride vapors by the solvent in the substantially or totally molten state.

Abstract: The invention relates to a method of separating zirconium and hafnium tetrachlorides using a solvent comprising firstly an alkaline metallic solvent comprising a salt made up of an alkali metal chloride and an acidic metal chloride A, for example a chloroaluminate or an alkaline chloroferrate, and secondly an acidic metal or metalloid chloride B of acidity that is less than that of the acidic metal chloride A. The acidic metal or metalloid chloride B is preferably selected from chlorides of Mg, Zn, and Cu. The method may be a continuous separation method by selective absorption of the tetrachloride vapors by the solvent in the substantially or totally molten state.

Abstract: The invention concerns a process and apparatus for electrochemical measurement of the concentration of oxide ions dissolved in a bath based on molten halides. The process is based on impedance measurement at a low current and a low overvoltage, between an indicator electrode, a reference electrode and a counter electrodes. The real value Z.sub.r of the impedance is determined for two frequencies, a low frequency Zr(B) (such as 15-25 Hz) and a high frequency Zr(H) (such as 10-100 kHz); the inverse of the concentration of oxide ions is a linear function of the difference between Zr(B) and Zr(H). This method has a high level of accuracy in the low ranges of concentration of oxide ions.

Abstract: A process for producing a strong, adherent protective layer on copper parts, with a high rate of covering of the substrate, by passivating anodization, characterized in that the copper parts are immersed in a liquid KF, 2HF bath and subjected to anodic current of low surface-related density which is less than 0.1 A/dm.sup.2, which current may be continuous or intermittent.

Abstract: A selective chlorination method of a mixture of simple or complex metallic oxides, comprising at least one of the elements to be used, iron, aluminum, titanium and silicon, as well as the impurities accompanying said elements, said method consisting of a grinding, a calcination, a placing in suspension in a bath of melted salts of the mixture of said metallic oxides and of their impurities and of an introduction of chlorinating agents into said bath maintained at a temperature which assures the volatility of at least one of the metallic chlorides formed; characterized by the fact that, in order to selectively extract the metallic chlorides formed from the bath, specific chlorinating mixtures are introduced into this bath by successive steps, said mixtures having increasing chlorinating power, and the introduction is in a number at the most equal to the usuable elements to be chlorinated.

Abstract: The present invention relates to a process for stabilizing a mixture of molten alkali metal nitrates and alkali metal nitrites usable particularly as a heat transfer fluid and to the stabilized mixture thus obtained.The process comprises adding to the mixture a quantity of alkali metal hydroxide such that the value of the logarithm of the ratio P(H.sub.2 O)/.vertline.OH.sup.- .vertline..sup.2 (where P(H.sub.2 O) denotes the partial pressure of water vapor expressed in atmospheres and .vertline.OH.sup.- .vertline. the hydroxide ion concentration expressed in moles/kg) is between a value b corresponding to the disproportionation of the nitrites into nitrate and nitric oxide and a value a corresponding to the appearance of peroxides, the values a and b being determined for a given nitrate/nitrite ratio, a given temperature and given partial pressures of the gases blanketing the mixture.