Method of pulp production

Claim 1

IN THE ACID SULFITE PRECOOKING OF WOOD CHIPS FOLLOWED BY ALKALINE DIGESTION, THE IMPROVEMENT WHICH COMPRISES REMOVING THE MAJOR PROPORTION OF THE SPENT ACID SULFITE LIQUOR FROM THE PRECOOKED CHIPS, FORTIFYING THE SPENT ACID SULFITE LIQUOR BY ADDING A SUFFICIENT AMOUNT OF CHEMICALS AND WATER TO REPLACE THE CHEMICALS AND WATER LEFT WITH THE WOOD CHIPS, USING THE FORTIFIED SPENT ACID SULFITE LIQUOR FOR A SIMILAR PRECOOKING OPERATION ON A FRESH BATCH OF CHIPS, SUBJECTING THE PRECOOKED CHIPS OF EACH BATCH WITHOUT WASHING AND CONTAINING THE RESIDUAL ADHERING AND IMBIBED SPENT ACID LIQUOR WITH ITS DISSOLVED ORGANIC MATTER TO AN ALKALINE DIGESTION, AND REMOVING ALKALINE BLACK LIQUOR FROM THE ALKALINE DIGESTION CONTAINING CHEMICALS AND ORGANIC MATTER FROM BOTH THE ACID AND ALKALINE STAGES, SAID PRECOOKING AND REMOVAL OF SPENT ACID SULFITE LIQUOR BEING CARRIED OUT SO THAT THE AMOUNT OF ORGANIC MATTER IN THE LIQUOR LEFT WITH THE CHIPS FROM THE PRECOOKING IS SUBSTANTIALLY EQUAL TO THE AMOUNT OF ORGANIC MATTER REMOVED FROM THE CHIPS IN THE PRECOOKING AND THE ORGANIC MATTER IN THE FORTIFIED SPENT ACID SULFITE LIQUOR REACHES A SUBSTANTIALLY STABLE VALUE, WHEREBY THE ALKALINE BLACK LIQUOR CONTAINS SUCCH A CONCENTRATION OF CHEMICALS AND ORGANIC MATTER THAT IS CAN BE TREATED EFFICIENTLY FOR THE RECOVERY OF CHEMICALS AND HEAT.