RECOVERY OF SODIUM HYDROXIDE FROM PULP WASTE

• Main Authors: TAKESHITA YUUKICHI, ITOU HAYAMIZU, NAGAI CHIAKI, OGAWA KATSUYOSHI
• Format: Patent
• Language: English
• Published: 13.09.1984
• Subjects: APPARATUS THEREFOR; CHEMISTRY; COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM,RUBIDIUM, CAESIUM, OR FRANCIUM; INORGANIC CHEMISTRY; METALLURGY; PAPER-MAKING; PRODUCTION OF CELLULOSE; PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCESFROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; TEXTILES

PURPOSE:A fine powder of a caustification agent such as Fe2O3, TiO2 or FiTiO3 is mixed with condensed pulp waste and burnt in a fluid bed furnace, then the product is fed into water to effect high-efficiency recovery of sodium hydroxide from pulp waste. CONSTITUTION:Pulp cooking waste 1 is introduced into evaporator 3 for concentration and sent to mixer 4. In the meantime, a caustification agent selected from Fe2O3, TiO2 and FeTiO3 is fed into the classifier 5 to separate into particles of more fine sizes and more cruder sizes than the fluidizing agent in the furnace 6. The fine particles are fed into the mixer where it is combined with the condensed pulp waste. The mixture is fed into the fluid bed furnace 6 and the crude particles are also fed into the furnace 6 to effect combustion to cause the reactions shown in equations I and II. Then, the product is introduced into water in the hydrolysis tank 8 to effect the reaction of equation III to form Fe2O3 and sodium hydroxide and sent to the clarifier 10 where sodium hydroxide 11 and Fe2O3 12 are separated and recovered respectively.