| abstract |
Chlorine is produced by oxidizing byproduced hydrogen chloride. An offgas containing hydrogen chloride as a byproduct is reacted (6) with oxygen at 300-500°C in the presence of a catalyst which contains chromic oxide (Cr₂O₃) as a principal component. The resulting gas is cooled rapidly and then washed (8) with water to recover vaporized chromium. The hydrogen chloride is then absorbed in water (9) to recover it as an aqueous hydrochloric acid solution. The still remaining portion of the resultant gas is washed with sulfuric acid (2l) to remove water from the same, followed by compression (28) and cooling (30). The resulting liquefied chlorine is separated (32). The still remaining gas composed principally of oxygen is thereafter returned to the oxidation step. |