| 摘要 |
PCT No. PCT/SE79/00046 Sec. 371 Date: Dec. 7, 1979 Sec. 102e Date: Nov. 15, 1979 PCT Filed: Mar. 2, 1979 Pub. No. WO79/00899 Pub. Date: Nov. 15, 1979. The digestion of the cellulose-containing material is performed with a digestion liquor containing sulphur and sodium followed by recovery and regeneration of said digestion liquor and bleaching of the cellulose-containing material with chlorine dioxide. The SO2-containing and possibly chloride-containing gas from the recovery boiler (11) of the process and from combustion of evil-smelling gases (20) is absorbed in an absorption liquor containing and alkali metal salt solution free of sulphur or sulphur compounds such as sulphide or thiosulphate, in a scrubber (27). The resulting scrubber liquor is mixed with acid residual solution (26) from the manufacture of chlorine dioxide, whereby sulphur dioxide (32) in gaseous state is returned to the process, whereafter the residual solution (34) free from SO2 is led to an evaporation and crystallization plant (35) for precipitation of alkali salts except chloride, substantially sodium sulphate, for obtaining a residual acid (37) consisting of chloride-containing sulphuric acid. The chloride-containing sulphuric acid is returned to the manufacture (19) of chlorine dioxide for generation chlorine dioxide, whereby the chloride content of the residual acid can be utilized. |
