FIELD: cellulose production. SUBSTANCE: cellulose is treated with ozone-containing gas in the mixer for internal stirring at the high shift strength, and gas is fed under pressure 1.1-15 bars. Mass concentration at whitening with ozone-containing gas is 3-20% temperature is 15-80 C and pH 1-8. Gas has 20-300 g/m3 ozone, preferably 50-150 g/m3. Volume ratio of gas to liquid at whitening is (1:0.5)-(1:8), preferably (1:1)-(1:6). Cellulose suspension is treated with ozone-containing gas after alkaline peroxide extraction or after alkaline oxygen extraction fortified with peroxide. After treatment with ozone-containing gas cellulose suspension is treated with peroxide and alkaline extraction is carried out. EFFECT: improved method of cellulose whitening. 6 cl, 6 dwg
