Acid-alkali process for the preparation of cellulose fibers

Claim 1

A PROCESS FOR LIBERATING AND PURIFYING FIBERS FROM BAGASSE WHICH CONSISTS IN IMMERSING THE BAGASSE, PRIOR TO ALKALINE TREATMENT THEREOF, IN DILUTE NITRIC ACID SOLUTION HAVING A CONCENTRATION OF ABOUT 2% AT ELEVATED TEMPERATURE BETWEEN 80* C. AND 110* C. FOR A PERIOD OF ABOUT ONE HOUR, REMOVING THE ACID SOLUTION AND WASHING THE BAGASSE, THEREAFTER IMMERSING THE BAGASSE IN DILUTE SODIUM HYDROXIDE SOLUTION HAVING A CONCENTRATION OF ABOUT 1% TO 3% AT ABOUT 95* C. FOR A PERIOD OF ABOUT ONE HOUR TO REDUCE THE SIZE OF FIBER BUNDLES AND FORM A PULP, MECHANICALLY AND VIOLENTLY AGITATING THE PULP BEFORE WASHING TO BREAK UP THE FIBER BUNDLES, THEREAFTER WASHING THE PULP, AGAIN IMMERSING THE PULP IN DILUTE SODIUM HYDROXIDE SOLUTION AT ABOUT 95* C. FOR A PERIOD OF ABOUT ONE HOUR, CHLORINATING THE PULP TO EFFECT BLEACHING AND REMOVAL OF ENCRUSTANTS, STEEPING THE PULP IN THE COLD IN 5% TO 14% SODIUM HYDROXIDE SOLUTION FOR A PERIOD OF ABOUT ONE HOUR, AND REBLEACHING THE PULP IN A HYPOCHLORITE SOLUTION WITH EXCESS ALKALINITY.