Patent ID: 7922875

Claim:
A method of enriching a heavy oxygen isotope by distillation, comprising: a first distillation step (a) of feeding oxygen and ozone generated by an ozonizer into a distillation column filled with a diluent gas, and separating the oxygen, and the ozone and the diluent gas; a step (b) of discharging the oxygen from a top of the distillation column; a step (c) of depressurizing the distillation column; a photodecomposition step (d) of introducing a mixed gas of the ozone and the diluent gas from a bottom of the distillation column into a photoreaction cell, and irradiating the mixed gas with a laser light to selectively decompose the ozone containing the heavy oxygen isotope; a second distillation step (e) of returning non-decomposed ozone and oxygen containing the heavy oxygen isotope obtained in the step (d) to the distillation column, and separating the oxygen, and the ozone and the diluent gas; a step (f) of liquefying the oxygen containing the heavy oxygen isotope using a condenser provided at the top of the distillation column, and extracting the oxygen as a product oxygen; a step (g) of extracting the non-decomposed ozone from the distillation column, decomposing the ozone into oxygen using an ozone decomposition device, and then returning the oxygen to the distillation column; a third distillation step (h) of separating the oxygen and the diluent gas; and a step (i) of externally discharging the oxygen separated in the step (h), wherein the first through third distillation steps are all conducted within a single distillation column.