IMPREGNATION OF CHIPS WITH AN ACID LIQUID PRIOR TO A SULPHATE PULPING PROCESS

摘要

The method is for pre-treatment of chips that are fed to a sulphate cooking process. Through acidification of the chips in an acidic treatment fluid with a subsequent draining of free treatment fluid before subsequent steaming or wet-steaming, a high concentration of free hydrogen ions is established within the chip pieces. When the chips are subsequently formed into slurry with preferably a sulphide-rich alkali cooking fluid, H₂S is formed locally in the chip pieces which gives a yield-increasing effect in the subsequent cooking step of 1-3%.