Treatment of spent sulfite liquor

Claim 1

IN A PROCESS FOR RECOVERING SPENT LIQUOR AFTER SODIUM BASE, SULFITE TREATMENT OF WOOD TO PROVIDE A HIGH QUALITY LIQUAR WITH LOW THIOSLFATE CONTENT FOR TREATING WOOD,THE STEPS OF CONCENTRATING THE SPENT LIQUAR BURNING THE SPENT LIQUOR TO FORM A SMELT, SAID BURNING BEINGDONE UNDER CONDITIONS WHICH MINIMIZE THE REMOVAL OF SULFUR AND CONVERT A MAJOR PORTION OF THE SULFUR IN THE LIQUOR TO SODIUM SULFIDE IN THE SMELT, DISSOLVING SAID SMELT TO PROVIDE AN AQUEOUS SOLUTION HAVING A PH IN EXCESS OF 11.0 AND A SODIUM SULFIDE CONCENTRATION OF LESS THAN ABOUT 1.2 MOLS PER LITER, TREATING SAID SOLUTION TO PROVIDE THE LIQUOR WITH LOW THISULFATE CONTENT BY SULFITING SAID SOLUTION WITH SULFUR DIOXIDE AT A TEMPERATURE BETWEEN ABOUT 60* C. AND 100* C. SO AS TO REDUCE THE PH TO BELOW 9.5 AND MUNTAIN THE PH OF THE SOLUTION ABOVE 7.0, SAID AQUEOUS SOLUTION AND SAID SULFUR DIOXIDE FLOWING CONCURRENTLY TO MINIMIZE THE EFFECTIVE CONTACT BETWEEN THE FULFUR DIOXIDE AND THE HYDROGEN FULFIDE PRODUCED DURING SULFITATION.