Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/02—Froth-flotation processes
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F13/00—Recovery of starting material, waste material or solvents during the manufacture of artificial filaments or the like
  • D01F13/02—Recovery of starting material, waste material or solvents during the manufacture of artificial filaments or the like of cellulose, cellulose derivatives or proteins
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
  • Y02P70/62—Manufacturing or production processes characterised by the final manufactured product related technologies for production or treatment of textile or flexible materials or products thereof, including footwear

Definitions

• This invention relates to a process for the clarification of fouled spin baths used in the viscose rayon manufacture.
• the cellulose xanthate 5 viscose is extruded through fine openings in socalled spinnerettes into a bath which regenerates hydrated cellulose to form a filament which maythen be spun with others to form rayon yarn.
• These spin baths contain salts and acids for delo composing the strongly alkaline cellulose xanthate.
• Typical baths contain from 8-10% of sulfuric acid, glucose and various salts such as sodium sulfate, sodium sulfite and the like.
• the alkali in the viscose reacts to form 15 sodium sulfate and the decomposition of the xanthic acid radical results in setting free a considerable amount of sulfur which is present in a very finely divided and sometimes colloidal form.
• the bath soon fouls with decomposition products including sulfur and requires clarification before the bath can be reused.
• the volume of spin baths used is very large, one-half liter of spin bath per minute per spindle being a common amount in the rayon industry. With the large volume of bath required it is of course economically undesirable to discard the fouled solution as it contains too large a quantity of valuable chemicals.
• spin baths are clarified by froth flotation such as is used in the ore dressing art. It is found that the sulfur and other impurities can be floated off from the bath with a very slight loss of bath and with the production of an extraordinarily clear bath for reuse.
• the flotation process is in some respect unique in that it is apparently not dependent on the use of any particular definite flotation agent. It is possible to fioat with air alone without any reagents or with the addition of frothers or collectors. This is most unusual as the ordinary flotation processes are rather rigidly limited to the use of particular classes of collecting agents.
• the present invention is not limited to any particular type of flotation machine. Excellent results are obtained with highly efiicient machines of the mechanical type such as a Fagergren machine. However, the present invention represents a peculiar situation because simple pneumatic machines can be used without serious 1055 in flotation efficiency. This is not the case with most flotation processes where the highly developed mechanical machines with their superior agitation and aerating efliciency have relegated the pneumatic machines to a relatively minor position in the art.
• the possibility of using extremely simple pneumatic machines in the present process is of great importance because the spin baths are strongly acid and hence any metallic equipment has to be rendered acid proof, which is a difllcult matter with mechanical machines having rotating parts. Pneumatic machines can of course be made of completely acid proof construction without any materially increased cost.
• Example 1 A fouled spin bath having a composition typical of that used in bobbin spinning and containing when fresh 130 grams sulfuric acid per liter, 250 grams sodium sulfate per liter and 14 grams zinc sulfate per liter was treated in an acid proof mechanical flotation machine of the Fagergren type.
• the bath was clarified by three methods, first with the use of no reagents, then with a dicresyldithiophosphoric acid known in the trade as Aerofloat 15, then with an alcohol frother containing a mixture of higher alcohols and known in the trade as 13-48, and finally with kerosene. In every case, the bath was thoroughly clarified and a good recovery of sulfur was obtained.
• the details of the tests appear in the following table. The volumes and weight parts given in the table are in the same system:
• Example 3 A spin bath typical of the pot spinning process was floated in a pneumatic machine as described in Example 2. The results with no reagents were substantially the same as the corresponding results in Example 1 and in a second test, when the reagent was Aerofloat 15, a slightly better grade of concentrate was obtained with a larger output from a given size machine.
• baths from the regeneration of hydrated cellulose from viscose which bath contains sulphur deposited out of solution which comprises subjecting the bath to froth flotation and removing the froth which contains the bulk of the turbid impurities.
• a method of clarifying fouled regenerating baths from the regeneration of hydrated cellulose from viscose which bath contains sulphur deposited out of solution which comprises subjecting the bath to froth flotation in the absence of flotation reagents and removing the froth which contains the bulk of the turbid impurities.
• a method of clarifying fouled regenerating baths from the regeneration of hydrated cellulose from viscose which bath contains sulphur deposited out of solution which comprises subjecting the bath to froth flotation in the presence of a dithiophosphoric acid compound, and removing the froth which contains the bulk of the turbid impurities.
• Example 2 lose from viscose which bath contains sulphur
• a spin bathas described in Example 1 was treated in a pneumatic flotation machine provided with an acid proof air distributor in the bottom and of acid proof construction throughout. The results were substantially the same as in Example 1.
• deposited out of solution which comprises subjecting the bath to froth flotation in the presence of a saturated hydrocarbon collector and removing the froth which contains the bulk of the turbid impurities.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Degasification And Air Bubble Elimination (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)

Priority Applications (6)

Applications Claiming Priority (6)

Publications (1)

Family

ID=10393448

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (1)

• 1937
  • 1937-07-07 US US152469A patent/US2153449A/en not_active Expired - Lifetime
• 1938
  • 1938-12-20 GB GB37063/38A patent/GB512111A/en not_active Expired
  • 1938-12-22 NL NL91195A patent/NL53876C/xx active
  • 1938-12-27 FR FR848075D patent/FR848075A/fr not_active Expired
• 1939
  • 1939-01-02 BE BE431956D patent/BE431956A/xx unknown
  • 1939-01-03 CH CH209352D patent/CH209352A/fr unknown

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