Method for the oxidation of black liquor

Claim 1

THE PROCESS OF TREATING BLACK LIQUORS OBTAINED IN THE PRODUCTION OF PAPER-MAKING PULP AND CONTAINING SODIUM SULPHIDE AND MALODOROUS ORGANIC SULPHIDES, DISULPHIDES AND MERCAPTANS, WHICH CONSISTS ESSENTIALLY OF OXIDIZING SAID MALODOROUS CONSTITUENTS OF THE BLACK LIQUOR TO CONVERT THEM INTO NON-MALADOROUS COMPOUNDS, SAID OXIDATION BEING EFFECTED BY NON-CATALYTICALLY TREATING SAID BLACK LIQUOR WITH AIR AT SUPERATMOSPHERIC PRESSURES IN THE RANGE OF FROM 10 TO 100 POUNDS PER SQUARE INCH WHILE MAINTAINING THE SAME AT A TEMPERATURE IN THE RANGE OF FROM 70* TO 220*F., SAID TREATMENT WITH AIR BEING EFFECTED BY DIFFUSING COMPRESSED AIR INTO SAID LIQUOR WHILE FEEDING THE LIQUOR AND THE COMPRESSED AIR INTO ONE END OF A REACTION ZONE IN WHICH A SUBSTANTIALLY CONSTANT PRESSURE WITHIN SAID RANGE IS MAINTAINED, AND DISCHARGING FROM THE OPPOSITE END OF SAID ZONE THE THUS OXIDIZED LIQUOR CONTAINING THE NON-MALODOROUS OXIDATION PRODUCTS OF SAID SULPHIDES, DISULPHIDES AND MERCAPTANS MIXED WITHIN EXCESS AIR.