Method of bleaching moist felted groundwood pulp

Claim 1

IN THE METHOD OF TRATING MOIST FELTED WOOD PULP CONTAINING SUBSTANTIAL AMOUNTS OF LIGNEOUS AND NON-CELLULOSIS MATERIALS HAVING A CONSISTENCY OF NOT LESS THAN 25% SOLIDS, THE STEPS WHICH COMPRISE IMPREGNATING SAID MOIST FELTED PULP WITH AN ALKALINE PEROXIDE SOLUTION AS THE SOLE CHEMICAL ADDITION TO EFFECT SELF CONTROLLED BLEACHING OF THE PULP, SAID ALKALINE PEROXIDE SOLUTION HAVING A PH OF FROM 9.5 TO 11 AND A TOTAL ALKALINITY OF FROM 0.35 TO 1.1% BY WEIGHT SODIUM OXIDE EQUIVALENT BASED ON BONE DRY PULP AND COMPRISING A PEROXIDE AND AN ALKALINE SALT INCLUDING AS AN ESSENTIAL INGREDIENT A SODIUM SALT SELECTED FROM THE GROUP CONSISTING OF SILICATE OF SODA, TRISODIUM PHOSPHATE, SODIUM PYROPHOSPHATE AND SODIUM TETRAPHOSPHATE, ACCUMULATING SAID IMPREGNATED FELTED PULP INTO A MASS OF SUBSTNATIAL VOLUME AND HAVING A RELATIVELY SMALL EXPOSED AREA TO INHIBIT DRYING OUT OF SAID MASS, ALLOWING SAID MASS TO REMAIN IN A MOIST FELTED CONDITION FOR FROM 5 HOURS TO SEVERAL WEEKS DURING THE INITIAL PERIOD OF WHICH TIME THE MAXIMUM BRIGHTNESS OF THE PULP IS ACHIEVED AND THE PH THEREOF IS AUTOMATICALLY LOWERED TO AT LEAST 8 AT THE POINT OF MAXIMUM BRIGHTNESS, AND OMITTING ANY FURTHER CHEMICAL ADDITIONS TO THE BLEACHED PULP TO INHIBIT COLOR REVERSION THEREOF AFTER OBTAINING SAID MAXIMUM BRIGHTNESS, THE BLEACHED PULP RETAINING MAXIMUM BRIGHTNESS, THE BLEACHED PULP RETAINING SUBSTANTIALLY ITS SAID MAXIMUM BRIGHTNESS FOR A PERIOD OF AT LEAST SEVERAL WEEKS.