Elemental fluorine is often manufactured electrochemically from a solution of KF in hydrogen fluoride and contains varying amounts of HF as impurity. The present invention provides a method for chamber cleaning using F.sub.2 which contains more than 0.1% by weight and equal to or less than 10% by weight of HF. Surprisingly, such an F.sub.2 is very well suited for the purpose of chamber cleaning. In a preferred embodiment, the F.sub.2 which contains more than 0.1% by weight and less than 2.5% by weight of HF is electrolytically produced, cleaned, delivered and used on site, without any pressurizing treatment. Omitting cleaning steps and process and using process conditions leaving a relatively high HF content in the F.sub.2 allows at the same time to omit pressurizing steps. The advantage is that less cleaning steps.

A method for producing fluorine gas including a fluorination step of obtaining a reaction mixture containing a major fluorinated substance that is a target component generated by fluorination of a raw material compound and by-product hydrogen fluoride, a separation step of separating the reaction mixture to obtain a main product component containing the major fluorinated substance and a by-product component containing the by-product hydrogen fluoride, a purification step of purifying the by-product component to obtain a recovered hydrogen fluoride component in which a concentration of an organic substance is reduced and a concentration of the by-product hydrogen fluoride is increased, an electrolysis step of performing electrolysis using the recovered hydrogen fluoride component as at least a part of an electrolyte to produce fluorine gas, and an introduction step of introducing the fluorine gas obtained in the electrolysis step into a reaction field for fluorination in the fluorination step.

A method for producing fluorine gas including electrolyzing an electrolyte in an electrolytic cell, measuring an electric energy accumulated after the electrolyte is placed in the electrolytic cell, and the electrolyzing is started, and sending a fluid generated in the inside of the electrolytic cell in the electrolyzing the electrolyte, to the outside of the electrolytic cell through a flow path. In the sending, the flow path is switched in accordance with the electric energy measured in the measuring an electric energy, such that the fluid is sent to a first flow path that sends the fluid to a first outside when the electric energy measured in the measuring an electric energy is not less than a predetermined reference value, or the fluid is sent to a second flow path that sends the fluid to a second outside when the electric energy is less than the predetermined reference value.

A method for producing fluorine gas including electrolyzing an electrolyte in an electrolytic cell, measuring an electric energy accumulated after the electrolyte is placed in the electrolytic cell, and the electrolyzing is started, and sending a fluid generated in the inside of the electrolytic cell in the electrolyzing the electrolyte, to the outside of the electrolytic cell through a flow path. In the sending, the flow path is switched in accordance with the electric energy measured in the measuring an electric energy, such that the fluid is sent to a first flow path that sends the fluid to a first outside when the electric energy measured in the measuring an electric energy is not less than a predetermined reference value, or the fluid is sent to a second flow path that sends the fluid to a second outside when the electric energy is less than the predetermined reference value.

A device for producing fluorine gas has a first flow path configured to send a fluid from the inside of an electrolytic cell through a mist removal unit configured to remove mist from the fluid to a fluorine gas selection unit and a second flow path configured to send the fluid from the inside of the electrolytic cell to the fluorine gas selection unit without passing through the mist removal unit and has a flow path switching unit configured to switch a flow path through which the fluid flows depending on the average particle size of the mist measured by an average particle size measurement unit. The second flow path has a clogging suppression mechanism configured to suppress clogging of the second flow path by the mist.

A device for producing fluorine gas has a first flow path configured to send a fluid from the inside of an electrolytic cell through a mist removal unit configured to remove mist from the fluid to a fluorine gas selection unit and a second flow path configured to send the fluid from the inside of the electrolytic cell to the fluorine gas selection unit without passing through the mist removal unit and has a flow path switching unit configured to switch a flow path through which the fluid flows depending on the average particle size of the mist measured by an average particle size measurement unit. The second flow path has a clogging suppression mechanism configured to suppress clogging of the second flow path by the mist.

A method for producing fluorine gas including electrolyzing an electrolyte in an electrolytic cell, measuring the current efficiency of fluorine gas production in the electrolyzing, and sending a fluid generated in the inside of the electrolytic cell in the electrolyzing the electrolyte, from the inside to the outside of the electrolytic cell through a flow path. In the sending, the flow path in which the fluid flows is switched in accordance with the current efficiency measured in the measuring the current efficiency, such that the fluid is sent to a first flow path that sends the fluid to a first outside when the current efficiency measured in the measuring the current efficiency is not less than a predetermined reference value, or the fluid is sent to a second flow path that sends the fluid to a second outside when the current efficiency is less than the predetermined reference value.

A method for producing fluorine gas including electrolyzing an electrolyte in an electrolytic cell, measuring the current efficiency of fluorine gas production in the electrolyzing, and sending a fluid generated in the inside of the electrolytic cell in the electrolyzing the electrolyte, from the inside to the outside of the electrolytic cell through a flow path. In the sending, the flow path in which the fluid flows is switched in accordance with the current efficiency measured in the measuring the current efficiency, such that the fluid is sent to a first flow path that sends the fluid to a first outside when the current efficiency measured in the measuring the current efficiency is not less than a predetermined reference value, or the fluid is sent to a second flow path that sends the fluid to a second outside when the current efficiency is less than the predetermined reference value.

There is provided a fluorine gas production device in which, even when an electrolytic solution containing hydrogen fluoride is electrolyzed at a high current density, a recombination reaction in the electrolytic solution and a recombination reaction in gas phase parts of an anode chamber and a cathode chamber are less likely to occur and the electrolytic solution can be electrolyzed with high current efficiency to produce fluorine gas. The fluorine gas production device includes an electrolytic cell (1), a partition wall (7) extending downward in the vertical direction from the ceiling surface inside the electrolytic cell (1) to partition the electrolytic cell (1) into an anode chamber (12) and a cathode chamber (14), an anode (3), and a cathode (5). The lower end of the partition wall (7) is immersed in the electrolytic solution (10) and a length (H) in the vertical direction of a portion immersed in the electrolytic solution (10) of the partition wall (7) is 10% or more and 30% or less of the distance from the bottom surface inside the electrolytic cell (1) to the liquid level of the electrolytic solution (10). The cathode (5) is completely immersed in the electrolytic solution (10) and the upper end of the cathode (5) is arranged at a lower position in the vertical direction relative to the lower end of the partition wall (7). The anode 3 is partially exposed from the liquid level of the electrolytic solution (10).

There is provided a fluorine gas production device in which, even when an electrolytic solution containing hydrogen fluoride is electrolyzed at a high current density, a recombination reaction in the electrolytic solution and a recombination reaction in gas phase parts of an anode chamber and a cathode chamber are less likely to occur and the electrolytic solution can be electrolyzed with high current efficiency to produce fluorine gas. The fluorine gas production device includes an electrolytic cell (1), a partition wall (7) extending downward in the vertical direction from the ceiling surface inside the electrolytic cell (1) to partition the electrolytic cell (1) into an anode chamber (12) and a cathode chamber (14), an anode (3), and a cathode (5). The lower end of the partition wall (7) is immersed in the electrolytic solution (10) and a length (H) in the vertical direction of a portion immersed in the electrolytic solution (10) of the partition wall (7) is 10% or more and 30% or less of the distance from the bottom surface inside the electrolytic cell (1) to the liquid level of the electrolytic solution (10). The cathode (5) is completely immersed in the electrolytic solution (10) and the upper end of the cathode (5) is arranged at a lower position in the vertical direction relative to the lower end of the partition wall (7). The anode 3 is partially exposed from the liquid level of the electrolytic solution (10).