Hydrogen iodide manufacturing method and hydrogen iodide manufacturing apparatus

A hydrogen iodide manufacturing method comprising a step of producing sulfuric acid and an aqueous solution of hydrogen iodide by:

• forming a first aqueous solution containing sulfur dioxide or sulfurous acid by adding sulfur dioxide to water;
• and mixing a second aqueous solution containing iodine and the first aqueous solution, wherein the sulfur dioxide is pressurized to a gauge pressure level not lower than 0.2 MPa when the sulfur dioxide is added to water, and the first aqueous solution is pressurized to a gauge pressure level not lower than 0.2 MPa when the first aqueous solution and the second aqueous solution are mixed with each other.

A method of producing hydrogen from iodide and sulfur dioxide, the method comprising

• producing an aqueous solution of hydrogen iodide and sulfuric acid by causing iodine-containing aqueous solution and sulfur dioxide to react with each other in a pressurized condition of not lower than 0.2 MPa in gauge pressure;
• separating the hydrogen iodide from the sulfuric acid, and
• thermally decomposing the hydrogen iodide to hydrogen.