Impure gaseous hydrogen chloride from organochlorosilane hydrolysis is freed of impurities by first scrubbing with an organochlorosilane, which may be the same or different from the organochlorosilane(s) hydrolyzed, and then further scrubbing with chloromethane. The purified gaseous hydrogen chloride is preferably used in chlorosilane synthesis.

Provided is a method for producing a hydrogen chloride that is capable of efficiently producing a hydrogen chloride with a simple facility. The hydrogen chloride is produced by a method including obtaining chlorine and hydrogen by electrolyzing an inorganic chloride aqueous solution of which a pH is 3 to 5, obtaining a crude hydrogen chloride by reacting the chlorine and the hydrogen obtained in the electrolyzing at 1000 C. to 1500 C. with a use of an excess quantity of the hydrogen with respect to the chlorine in a molar ratio, dehydrating the crude hydrogen chloride obtained in the reacting, and compressing and liquefying the dehydrated crude hydrogen chloride obtained in the dehydrating, and purifying the liquid crude hydrogen chloride by distillation.

A process of separating phosgene and hydrogen chloride, comprises: conveying a mixed stream containing hydrogen chloride and phosgene into a distillation column; withdrawing from the distillation column a bottom stream containing phosgene; withdrawing a top stream containing hydrogen chloride; compressing at least a portion of the top stream and at least partially condensing the compressed top stream to form a liquid stream, decompressing at least a portion of the liquid stream to form a cooled liquid stream and a cooled gas stream; and recycling the cooled liquid stream to the top of the distillation column as a reflux; the process additionally comprising temporarily introducing an absorbing solvent into the distillation column, in particular during starting-up and/or shutting-down of the process. The process allows for safe operation even when hydrogen chloride production only gradually begins or decreases, without the necessity of storing hydrogen chloride.

A hydrogen gas recovery system according to the present ingestion is configured by a condensation and separation apparatus (A) that condenses and separates chlorosilanes from a hydrogen-containing reaction exhaust gas exhausted from a polycrystalline silicon production step, a compression apparatus (B) that compresses the hydrogen-containing reaction exhaust gas, an absorption apparatus (C) that absorbs and separates hydrogen chloride by contacting the hydrogen-containing reaction exhaust gas with an absorption liquid, a first adsorption apparatus (D) comprising an adsorption column filled with activated carbon for adsorbing and removing methane, hydrogen chloride, and part of the chlorosilanes each contained in the hydrogen-containing reaction exhaust gas, a second adsorption apparatus (E) comprising an adsorption column filled with synthetic zeolite that adsorbs and removes methane contained in the hydrogen-containing reaction exhaust gas, and a gas line (F) that recovers a purified hydrogen gas having a reduced concentration of methane.

Provided is a method for producing a hydrogen chloride that is capable of efficiently producing a hydrogen chloride with a simple facility. The hydrogen chloride is produced by a method including causing an inert gas to be in gas-liquid contact with a hydrochloric acid in which a concentration is 20 mass % to 50 mass %, distilling the hydrochloric acid with which the inert gas is in gas-liquid contact in the gas-liquid contact and separating a hydrogen chloride from the hydrochloric acid to obtain a crude hydrogen chloride, dehydrating the crude hydrogen chloride obtained in the separating, and compressing and liquefying the dehydrated crude hydrogen chloride obtained in the dehydrating, and purifying the liquid crude hydrogen chloride by distillation.

A method includes injecting a feed stream including a hydrogen halide and water into a vapor liquid separator. The feed stream has a liquid phase and a vapor phase. The method further includes separating the liquid phase and the vapor phase in the vapor liquid separator to form condensate and vapor, and discharging the condensate from the vapor liquid separator in a liquid stream. The method also includes discharging the vapor from the vapor liquid separator in a vapor stream.

The invention relates to an improved process for making available the coproduct hydrogen chloride obtained in the preparation of an isocyanate by phosgenation of the corresponding amine for a desired subsequent use (i.e. a chemical reaction), in which part of the total hydrogen chloride obtained is isolated in gaseous form at a pressure which is higher than the pressure desired for the subsequent use of the hydrogen chloride by lowering the pressure of the crude product from the phosgenation and the remaining part of the total hydrogen chloride obtained is separated off at a pressure lower than that desired for the subsequent use from the liquid crude product from the phosgenation remaining after lowering of the pressure and is subsequently compressed to a pressure which is higher than that desired for the subsequent use, and in which the two hydrogen chloride streams obtained in this way are, preferably together after having been combined, purified so as to give a purified hydrogen chloride at a pressure which is higher than the pressure desired for the subsequent use.

This invention describes a hydrometallurgical process for the recovery and separation of valuable elements, in particular gold and silver, from a feed material comprising a refractory, intractable or otherwise poorly responding to conventional treatment routes ores, concentrates and other materials. In particular, the process is a process integrated into one or more existing value element extraction processes.

The invention relates to a method of separating a phosgene- and hydrogen chloride-comprising stream (5), wherein said method comprises conveying the hydrogen chloride- and phosgene-comprising stream (5) into a distillation column (1), withdrawing at the bottom of the distillation column (1) a phosgene-comprising stream (7) and withdrawing at the top of the column an essentially hydrogen chloride-comprising stream (9). At least a portion of the stream (9) withdrawn at the top is compressed and at least partially condensed and at least a portion of the liquid and compressed essentially hydrogen chloride-comprising stream is decompressed and recycled into the top of distillation column (1) as reflux.

Impure gaseous hydrogen chloride from organochlorosilane hydrolysis is freed of impurities by first scrubbing with an organochlorosilane, which may be the same or different from the organochlorosilane(s) hydrolyzed, and then further scrubbing with chloromethane. The purified gaseous hydrogen chloride is preferably used in chlorosilane synthesis.