Innovative technologies are shown in red: (1) HI decomposer with membrane for H₂ separation, (2) direct feed of gas phase HI and I₂ into the HI distillation column, and (3) heat recovery from the Bunsen reaction by depressurized flash H₂SO₄ concentration, where HIx denotes a mixture of HI, I₂, and H₂O, minor compounds are within parentheses, Conc. represents concentrated, Dil. represents dilute, and Azeo. represents pseudo-azeotropic.