A METHOD OF RECOVERING CHEMICALS FROM CHLORIDE-CONTAINING GREEN LIQUOR

摘要

The invention relates to a method of recovering chemicals from chloride-containing green liquor by precarbonating the green liquor by means of flue gases into hydrosulfide and soda, by removing hydrosulfide from the precarbonated solution in the form of hydrogen sulfide, by evaporation crystallizing the chloride- and soda-containing solution in order to separate the chloride salt from the alkaline solution. In order to reduce releases of hydrogen sulfide, the produced hydrogen sulfide is absorbed into a soda solution and/or an alkaline solution in order to produce a solution suitable for the preparation of white liquor, whereas the hydrogen sulfide which remains unabsorbed is returned to the precarbonation stage, in which the hydrogen sulfide is absorbed substantially completely. By means of the invention it is possible to achieve a closed cycle of chemicals without the chloride load of the system increasing, and at the same time the chloride is recovered and returned to the bleaching.