METHOD FOR PRODUCING KRAFT PULP

• Main Authors: FURUSHO SABURO, KONO NORIO, WAKAMOTO SHIGERU
• Format: Patent
• Language: English
• Published: 03.06.2004
• Edition: 7
• Subjects: APPARATUS THEREFOR; PAPER-MAKING; PRODUCTION OF CELLULOSE; PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCESFROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; TEXTILES

PROBLEM TO BE SOLVED: To provide an industrially advantageous method for producing kraft pulp with which accumulation of especially potassium impurities is prevented and chemicals used in the process are effectively utilized. SOLUTION: There are provided a potassium ion removing step (G) of passing a solution of collected ash recovered from a combustion waste gas in a black liquor combustion step (E) with a dust collector and dissolved in water through a packed bed of a sodium type cation exchange resin, adsorbing and removing potassium ions, and a regeneration step (H) of the cation exchange resin used in the potassium ion removing step (G) with an aqueous solution of caustic soda in the method for producing the kraft pulp. A fraction recovered from the potassium ion removing step (G) and rich in sodium sulfate and sodium carbonate is circulated through a black liquor concentration step (D) and a caustic soda waste liquor recovered in the regeneration step (H) is further reused in the bleaching step (C). COPYRIGHT: (C)2004,JPO