Treatment of spent sulfite liquor

Claim 1

IN A SODIUM BASE, SULFITE PULPING PROCESS, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF CONCENTRATING THE SPENT LIQUOR FROM THE PULPING PROCESS, BURNING THE CONCENTRATED LIQUOR TO PROVIDE A SMELT HAVING A SULFIDITY OF BETWEEN ABOUT 30 PERCENT AND ABOUT 70 PERCENT, THE REDUCTION OF SAID SMELT BEING IN EXCESS OF 80 PERCENT, DISSOLVING SAID SMELT TO PROVIDE AN AQUEOUS SOLUTION AND BOILING SAID SOLUTION HAVING A SULFIDITY BETWEEN ABOUT 30 PERCENT AND ABOUT 70 PERCENT AT A RATE IN EXCESS OF 15 GRAMS OF VAPOR PER MINUTE PER SQUARE FOOT OF SURFACE AREA DURING ADDITION OF SODIUM BISULFITE SOLUTION TO SAID AQUEOUS SOLUTION IN AN AMOUNT SUFFICIENT TO PROVIDE SUFFICIENT SODIUM BISULFITE TO REACT WITH SUBSTANTIALLY ALL OF THE SODIUM SULFIDE IN SAID AQUEOUS SOLUTION, WHEREBY DIRECT SULFITATION OCCURS, AND RAPIDLY REMOVING THE HYDROGEN SULFIDE FROM THE RESULTING BOILING SOLUTION, WHEREBY FORMATION OF SODIUM THIOSULFATE AND ASSOCIATED SUBSTANCES IS SUBSTANTIALLY AVOIDED.