PROCESS FOR THE PREPARATION OF THE DIGESTING LIQUOR REQUIRED IN A NEUTRAL SULFITE COOKING WITH AN ADDITION OF ANTHRAQUINONE

摘要

A process for the preparation of a neutralsulfite digesting liquor and for adjusting the pH of the liquor while starting from a sodium-sulfite/sodium-carbonate solution that contains sodium bisulfite and/or sodium bicarbonate. The pH of the solution is raised to the pH-range of 8 to 11 by stripping carbon dioxide off the solution by means of water vapour or some other inert gas. The final adjustment of the pH of the cooking liquor can be performed by means of sodium hydroxide.