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
  • D21C3/00—Pulping cellulose-containing materials
  • D21C3/22—Other features of pulping processes
  • D21C3/26—Multistage processes

Definitions

• My invention comprises a complete process by which the bagasse of sugar cane may be treated to produce therefrom an excellent grade of cellulose.
• My invention is an 1mprovement over that disclosed and claimed in my Patent No. 1,630,142, dated May 24;, 1927, an application for a reissue of which is now pending.
• the present application 1s a continuation in part of United States application Serial No. 192,785, filed May 19, 1927.
• the drying of the bagasse andthe subsequent separation of the fibres is preferably carried out by the process described and claimed in my co-opending application-Serial No. 366,825 filed May 29, 1929.
• This process comprises air drying of the bagasse over a period of one or two weeks in a building provided with perforated floors and side walls open to the atmosphere, the bagasse being loosely spread about one or two' feet deep on the perforated floors and a' gentle current of air forced throu l1 and over the bagasse.
• the bagasse 1s then "treated preferably in a hammer-mill which breaks up the hard epidermis into a powdery form and partially opens up the fibrous art to detach the parenchyma and smaller fi res from the longer fibres.
• This treatment of the fibres is of particularvalue as a step in the elimination of the natural coloring matters and of the sugar content, which latter amounts to about one-and one-half to three per cent. or evenmore of the weight of the dry bagasse fibres. It is absolutely essential in order to obtain a good grade of paper stock for the sugar to be completely eliminated as otherwise it is impossible to bleach to'a. pure white product.
• I add a cold solution containing sodium sulphite.
• the amount of the sulphite in solution bein about onehalf to two per cent. of the fibre weight.
• the entire quantity of sodium sulphite amounting to about one and onehalf to six kilograms is dissolved in about 100 liters of water, and 200 to 400 liters of water are added coldto the solution in the cooker to reduce the temperature thereof to sulphite solution, the mixture is now heated matters.
• the fibers are then washed with addition to the washed fibre of a weak causcaustic tic solution, comprising about 1,000 liters of otash, caustic soda and sodium or other suitable sulphite in the proportions of about .3 to .6% caustic potash, 3 to 5% caustic soda and to 1 of the sulphite.
• the mixture is now heated by the addition of live steam in quantity suflicient to add about 200 liters of water to the solution and the temperature maintained around 130 C. for from four toeight hours.
• the treatment is .efi'ected in ⁇ a closed cooker, the pressure within which is accordingly raised to about 1 to 2 atmospheres.
• the particular proportions of the various chemicals depend upon the age of the bagasse and also upon the soil in which the sugar cane is grown. In place of the caustic soda additional caustic potash could be used, but this is not preferred on account of the greater expense involved.
• the silica is removed by the caustic poash, the vegetable glue is dissolved, the last traces of the coloring matterare destroyed, the resinous matter and vegetable iqeaaoa wax are saponified oremulsified by the combination of chemicals used, and any epidermis or parenchyma remaining with the fibres has been so acted upon as to render them harmless during the further treatment and manufacture of the cellulose.
• soap preferably of the type of Marseilles soap; about one to three kilograms of the dry soap being in solution in about 1,000 liters of water.
• the material in solution is then heated in the heaters to about 507 0 C.
• the soap solution washes out the last traces of the resins, waxes and gums. This solution is then removed and may, if desired, be
• the recouery of by-products is of impor-; tance in my novel process as it substantially lowers the cost thereof.
• By-products obtainable from my process include high grade cellulose from theshort fibres of the bagasse, when these are not added to the longer fibres in the above process, sweetening syrups, fertilizers, filling material for the plastic arts or catalogaoa for explosives, waxes, resins, glues, etc. A description of the various processes by means of which these by-productsmay be obtained will now be given.
• This separation briefly, is effected by air flow tation methods to first remove the powdered epidermis and dust, followed by screening,
• I may obtain a b product from the short fibres of considera is strength and of a very good light color, suitable, without bleaching, for newspapers or the like or suitable when bleached for other uses oficellulose. It is not essential to use solution A in this case, but its use is preferred in order to enrich the solution with the sugar from the fibres...
• I When using the unconditioned solutions, I agitate the short fibres for from four to six hours in solution B, maintain the temperature at about C. by exhaust steam of the plant and then wash them, using preferably the wash water from the longer fibresand finally treat the fibres with the soap solution, which may also be that used in the treatment of the longer fibres.
• Vegetable waxes, glues, and resins are precipitated by the use of acids or in any other known manner from the alkali solution afte its use in treating the fibres.
• parenchyma separated in the first part of my process from the other-components oi the'bagasse, may be sold without treatment as a filler for explosives, or, if desired, the sugar contents contained therein may be recovered,
• the sugars which amount to about 3% to 5% of the total, may be removed from the parenchyma by treatment with so much of solution A with or without addition of fresh lime andsulphite solution as is necessary to bring the sugars into solution.
• This solution is then drawn oil combined with all of solution A remaining from the treatment of the long or short fibres, which solutioncontains the sugars removed from ths fibres and added to the molasses ofthe sugar plant in such proportions as to reduce the specific gravity to 8 to 12 Be,
• This miXture'I then pass through filter presses, condense the filtrate to about 33 Be, bleaching at the same time to a crystal clear syrup containing the sugars.
• This syrup is of value'as a sweetening, material for edible products. It hasa peculiar and pleasant aroma and fiavor,
• the parenchyma after the above extraction of the sugars, may besold separately as filling material for the plastic arts, or may be added to the separated epidermis and dust and the whole used as a "fertilizer, as may also be used the filter cakes remaining in the presses after filtrationof the sugar containing solution.
• the cellulose obtained by my improved process is of a particularly fine quality. It has a high. alpha rcontent and is readily bleachable to a pure white color.
• A-process for treating bagasse fibres which comprises first treating the fibres .in a clear saturated solution of lime, later adding thereto a solution containing a suitable sulphite then treating the fibres in a solution containin caustic potash and a suitable sulphite and S11 sequently washing the fibres in a soap solution.
• a process for treating bagasse fibres which comprises first treating the fibres in a clear saturated solution of lime, later adding thereto a solution of sodium sulphite, then treating the fibres in a solution containing caustic potash, caustic soda and sodium sulphite and subsequently washing the fibres in a soap solution.
• process for treating the bagasse of sugar cane which comprises first separating epidermis, parenchyma, and, other foreign materials from the fibres, then treating the separated fibres in a clear lime solution and heating the same while maintaining the temperature below the boiling point, then reducing the temperature While adding an alkaline solution containing sulphite ions and again heating to a temperature below the boiling point, then removing the solution and thereafter treating the fibres with a weak alkali solution.
• step in the process for treatin the bagasse of sugar cane which comprises ieating bagasse fibres with a clear lime solution to a temperature in the neighborhood of 90 0., then reducing the temperature to about C. by the addition of cold Water and thereafter adding a solution of sodium sulphite and raising the temperature to its initial value.
• process for treating the bagasse of sugar cane comprising first separating short fibres, epidermis, dust and parenchyma from the longer fibres, then treating the separated moaaea longer fibres in a clearsaturated solution of lime, followed by the addition thereto of a solution of sodium sulphi-te, then removing the solution, washing the fibres and then heating the same in a solution, containing caustic potash, caustic soda and sodium sulphite, then removing the solution and again washing the fibres, and finally beating the fibres in a heated solution of soap.
• Additional steps in the process according to claim 5 comprising separating the shorter fibres from the other material separated from the longer fibres, then heating the separated short fibres with the-alkali solution removed after the treatment of the longer fibres, then washing the shorter fibres moisture content of the bagasse, then mechanically separating the longer fibres from the remainder of the bagasse, treating the separated fibres in a clear lime solution to which a solution of sodium sulphite is added thereafter, then removing the solution from the fibres, washing the fibres and subsequent ly treating the fibres in a weak caustic solution.
• a step in the process of treating the ba gasse of sugar cane which comprises treat ng separated fibres? of ,bagasse in a clear lime solution while maintaining the temperature below the boiling point of the solution, then adding a cold solution of a suitable sulphite andreheating the mixture to a temperature below the boiling point.
• sulphite solution is sodium sulphi-te in amount equal to about one-half to two percent of the weight of the bagasse fibres.

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• Polysaccharides And Polysaccharide Derivatives (AREA)
• Fats And Perfumes (AREA)
• Paper (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=6059321

Family Applications (1)

Country Status (3)

Cited By (2)

• 1928
  • 1928-02-10 GB GB4267/28A patent/GB287516A/en not_active Expired
  • 1928-02-29 FR FR650194D patent/FR650194A/fr not_active Expired
• 1929
  • 1929-06-08 US US369525A patent/US1792202A/en not_active Expired - Lifetime

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