Pulp manufacture

Claim 1

IN A PROCESS OF PULP MANUFACTURE OF THE CHARACTER DESCRIBED, THE RECOVERY STEPS OF REACTING IN A DIRECT GASLIQUID COUNTERCURRENT CARBONATION STEP A SOLUTION OF SODIUM SULPHIDE RECOVERED IN OXIDIZATION AND REDUCTION STEPS FROM SPENT COOKING LIQUOR WITH A MIXTURE OF GASES INCLUDING CARBON DIOXIDE PRODUCED IN SAID OXIDIZATION STEP FOR CONVERTING SULPHIDES IN SAID SOLUTION TO CARBONATES AND BICARBONATES, REMOVING SULPHUR FROM SAID SOLUTION IN THE FORM OF GASEOUS HYDROGEN SULPHIDE AS A GASEOUS PRODUCT OF SAID CARBONATION STEP, RECYCLING SAID GASEOUS HYDROGEN SULPHIDE THROUGH SAID OXIDIZATION STEP TO CONVERT SAID HYDROGEN SULPHIDE TO GASEOUS SULPHUR DIOXIDE, ABSORBING SAID SULPHUR DIOXIDE INTO SAID SOLUTION OF CA RBONATES AND BICARBONATES FOR REUSE AS PULP COOKING LIQUOR, AND EXHAUSTING TO THE ATMOSPHERE A LIMITED PORTION OF EFFLUENT GASES FROM SAID CARBONATION STEP SUBSTANTIALLY FREE OF HYDROGEN SULPHIDE.