Patent ID: 7785542

Claim:
A hydrogen iodide manufacturing apparatus for producing hydrogen iodide and sulfuric acid by causing iodine, sulfur dioxide and water to react with each other, the apparatus comprising: a sulfur dioxide dissolving tank that is a pressure-resistant container for producing aqueous solution of sulfur dioxide by mixing sulfur dioxide and water; a sulfur dioxide source for supplying pressurized sulfur dioxide into the sulfur dioxide dissolving tank; a reaction tank that is a pressure-resistant container for causing the reaction to take place in a pressurized condition; a pipe for supplying the aqueous solution of sulfur dioxide produced in the sulfur dioxide dissolving tank into the reaction tank; iodine-containing aqueous source for supplying iodine-containing aqueous solution into the reaction tank; and at least one back pressure valve for discharging gas therethrough from the sulfur dioxide dissolving tank and the reaction tank, so as to maintain pressure in the sulfur dioxide dissolving tank and the reaction tank above a predetermined level above the atmospheric pressure.