Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
  • D21C9/083—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching with inorganic compounds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S162/00—Paper making and fiber liberation
  • Y10S162/05—Alpha cellulose

Definitions

• the object of my invention is to provide a process of treating paper pulp through which it is possible to transform the soda pulp or sulphate pulp into a pulp that can be easily bleached.
• the process according to my invention consists essentially in subjecting the pulp successively to washing in a very diluted alkaline lye, washing in a very hot solution of an alkaline-earth base and chlorine water or soluble chlorides, and an acid treatment.
• the process according to my invention is very little expensive and can be applied for industrial purposes without necessitating any expensive supplementary plant.
• the pulp is subjected to a second washing in a very diluted alkaline lye (up to 1% NaOH, or NaOH mixed with NazCOs). That washing treatment may be performed at a temperature of 'about 80-90 C.
• the temperature may be as high as 110 C. if the treatment is performed under a pressure of about 1 kilogram per square centimeter. After removing the lye, which may be utilized two or three times, the mass is first rinsed in ordinary water, and the pulp is subjected to a qthird washing in a hot solution of an alkaline .earth base and chlorine water or soluble chlorides (for instance up to 0.4% CaO and 0.4% NaCl).
• a small quantity'of the lime and of the. salt is absorbed by the mass and remains therein during these ordinary treatments while the purifying of the cellulose is being carried on.
• the sec ond washing that is the washing with an alkaline lye
• the third washing that is the washing with av solution of an alkaline earth and of a salt, may be prolonged.
• the mass is treated with a dilute solution of sulphuric acid (about 3 kilograms of sulphuric per 100kilograms of dry pulp).
• a solution of sodium chloride v is added (about 2 or 3 kilograms per 100 kilograms of dry pulp).
• soda pulp or the sulphate pulp that has been thus treated can then be bleached as easily as bisulphite pulp.
• the pulp may be subjected first to one of the washing treatments above referred to (very dilute alkaline solution, or hot solution of an alkaline earth base and of chlorine water or soluble chlorides), at a relatively low temperature, which may however be as high as '70-80 C., then to an acid treatment, for instance in sulphuric acid of very low concentration.
• the pulp thus treated is then subjected to a preliminary bleaching step with, for instance, from 1 to 2% of active chlorine.
• Said chlorine may be supplied by a solution of calcium chloride CaOClz or calcium hypochlorite (eau de Javel).
• the pulp is subjected to the other washing operation (hot solution of an alkaline earth base and chlorine water or soluble chlorides, or very dilute alkaline solution, as the case may be) and then to an acid treatment, for instance with hydrochloric acid tht is not very much concentrated.
• the other washing operation hot solution of an alkaline earth base and chlorine water or soluble chlorides, or very dilute alkaline solution, as the case may be
• an acid treatment for instance with hydrochloric acid tht is not very much concentrated.
• the process according to my invention is particularly well adapted for sulphate pulp or soda pulp, but it will readily be understood that it may be of very high interest for other paper pulps, for instance for bisulphite pulp.
• a method of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to a washing with a dilute solution of lye, to a washing with a hot solution of an alkaline earth base and of a chlorine containing water-soluble material of the group comprising chlorine and soluble chlorides, and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a method of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline-earth base and of a soluble chloride,,and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp or sulphate pulp which comprises subjecting the pulp to an ordinary washing, to a washing with a hot solution of an alkaline earth base in a liquid containing chlorine, and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp or sulphate pulp which comprises subjecting the pulp to an ordinary washing, to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base in a liquid containing chlorine, and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp or sulphate pulp which comprises subjecting the pulp to an ordinary washing, to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base in chlorine water, and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to an ordinary washing, then to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base and a soluble chloride, and to an acid treatment, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to an ordinary washing, then to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base in chlorine water, and to the action or sulphuric acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to an ordinary washing, then to a Washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base in chlorine water, and to the action of hydrochloric acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises subjecting the pulp to an ordinary washing, then to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base in chlorine water, and to the action of sulphurous acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises, subjecting the pulp to an ordinary washing, then to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base and a soluble chloride, and to the action of sulphuric acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises, subjecting the pulp to an ordinary washing, to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base and of a soluble chloride, and to the action of hydrochloric acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp andsulphate pulp which comprises, subjeoting the pulp to an ordinary washing, to a washing with a dilute alkaline lye, to a washing with a hot solution of an alkaline earth base and of a soluble chloride, and to the action of sulphurous acid, whereby the pulp thus treated can be easily bleached.
• a process of treating paper pulp and particularly soda pulp and sulphate pulp which comprises, subjecting the pulp to a washing with a dilute alkaline lye at a temperature of less than subjecting to an acid treatment, and then to a preliminary treatment by means of chlorine, washing with a hot solution of an alkaline earth base in a liquid containing chlorine, and treating by an acid.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9682653

Family Applications (1)

Country Status (2)

Cited By (3)

• 0
  • FR FR742062D patent/FR742062A/fr not_active Expired
• 1932
  • 1932-10-15 FR FR43006D patent/FR43006E/fr not_active Expired
  • 1932-11-23 US US644135A patent/US1968223A/en not_active Expired - Lifetime

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