Central Glass Company, Limited

Nobuyuki Tokunaga

Akifumi Yao

Akiou Kikuchi

Tatsuo Miyazaki

Yasushi Kita

Yosuke Nakamura

Keita Nakahara

Shirou Moroi

Keizo Kojima

The present invention provide a water content measurement method for a hydrogen fluoride-containing compound represented by the general formula: XF.nHF (where X is either one of K, NH, Na and Li; and n is a rational number greater than 0), including the steps of causing thermal decomposition of the hydrogen fluoride-containing compound, thereby generating a thermal decomposition gas, and then, determining the water content of the hydrogen fluoride-containing compound by quantification of the water content of the thermal decomposition gas. By this measurement method, it is possible to accurately quantify the content of water in the hydrogen fluoride-containing compound XF.nHF.

Method and device for measuring water content in hydrogen fluoride-containing fluoride salt compounds

A provided emergency stop facility includes an alternative gas supply facility capable of supplying a cooling medium in a refining device as an alternative gas instead of an entrained gas shut-off by closure of an entrained gas shut-off valve with loss of a driving source caused by the emergency stop; an alternative entrained gas shut-off valve switching between supply and shut-off of an alternative gas to a hydrogen fluoride supply passage; and an instrumentation gas supply facility for emergency stop having an instrumentation gas shut-off valve enabling supply of an instrumentation gas by opening with loss of the driving source caused by the emergency stop, wherein at the emergency stop of the fluorine gas generating apparatus, the alternative entrained gas shut-off valve is opened upon receipt of the supply of the instrumentation gas, and the alternative gas is supplied to the hydrogen fluoride supply passage.

Fluorine gas generating apparatus

A fluorine gas generating apparatus generating a fluorine gas by electrolyzing hydrogen fluoride in molten salt, includes: an electrolytic cell including, above a liquid level of molten salt, a first gas chamber into which a product gas mainly containing the fluorine gas generated at an anode immersed in the molten salt and a second gas chamber separated from the first gas chamber into which a byproduct gas mainly containing a hydrogen gas generated at a cathode immersed in the molten salt; a hydrogen fluoride supply source retaining hydrogen fluoride to be replenished in the electrolytic cell; a refining device trapping a hydrogen fluoride gas evaporated from the molten salt in the electrolytic cell and mixed in the product gas generated from the anode to refine the fluorine gas; and a recovery facility conveying and recovering the hydrogen fluoride trapped in the refining device in the electrolytic cell or the hydrogen fluoride supply source.

A fluorine gas generating apparatus includes an electrolytic cell where the molten salt is retained and which is separated and divided above the liquid level of the molten salt into a first gas chamber where a product gas mainly containing a fluorine gas generated at an anode immersed in the molten salt is led and a second gas chamber where a byproduct gas mainly containing a hydrogen gas generated at a cathode immersed in the molten salt is led, and a refining device refining the fluorine gas by coagulating with a cooling medium and trapping a hydrogen fluoride gas evaporated from the molten salt in the electrolytic cell and mixed in the product gas generated from the anode. The cooling medium for coagulation of the hydrogen fluoride gas in the refining device and discharged is re-used as a utility gas used at spots in the fluorine gas generating apparatus.

The invention relates to a method for producing nitrogen trifluoride by gas-solid reaction. This method includes the steps of (a) providing a packed-bed-type vessel filled with a particulate solid of an ammonium complex of a metal fluoride; (b) introducing a fluorine-containing gas into the vessel to allow the fluorine-containing gas to flow upwardly through the vessel such that fluorine of the fluorine-containing gas is reacted with the particulate solid in the vessel, thereby to obtain a reaction gas containing nitrogen trifluoride; and (c) separating the nitrogen trifluoride from the reaction gas. A part of the reaction gas flowing out of the vessel may be introduced into the vessel, and thereby circulated through the vessel. The yield of nitrogen trifluoride becomes substantially improved by this method.

Method for producing nitrogen trifluoride by gas-solid reaction

The invention relates to a chemical vapor deposition (CVD) method for forming tungsten carbide, W.sub.3 C, by subjecting a gas mixture of tungsten hexafluoride, hydrogen and an aromatic hydrocarbon, e.g. benzene, to vapor phase reaction at an elevated temperature. The reaction temperature can be lowered to the extent of 250.degree. C. and the reaction can be carried out even at normal pressure, not necessarily under reduced pressure, by proportioning tungsten hexafluoride, hydrogen and the hydrocarbon such that in the gas mixture the atomic ratio of C to W falls in the range from 2 to 10 while the atomic ratio of H to C is not lower than 3. By this method a W.sub.3 C film excellent in glossiness can be deposited on various metal parts without adversely affecting the metal parts by the elevated temperature.

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Ube, Japan

Nobuyuki Tokunaga