US2933766A - Granulation method - Google Patents

Granulation method Download PDF

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Publication number
US2933766A
US2933766A US655682A US65568257A US2933766A US 2933766 A US2933766 A US 2933766A US 655682 A US655682 A US 655682A US 65568257 A US65568257 A US 65568257A US 2933766 A US2933766 A US 2933766A
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United States
Prior art keywords
screen
granulating
granulated
mesh
mass
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Expired - Lifetime
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US655682A
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English (en)
Inventor
Fred A Bickford
Forrest I Peters
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Individual
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Priority to BE567206D priority Critical patent/BE567206A/xx
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Priority to US655682A priority patent/US2933766A/en
Priority to FR1205593D priority patent/FR1205593A/fr
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/28—Slip casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
    • B01J2/20—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by expressing the material, e.g. through sieves and fragmenting the extruded length
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/30—Drying methods
    • 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
    • Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
    • Y10S425/101—Aggregate and pellet

Definitions

  • This invention relates to the granulation of finely divided materials, particularly ceramic materials, preparatory to molding into pellet, tablet, or other form for direct use or for subsequent processing, such as sintering.
  • a more specific purpose is to provide such a method which is capa* ble of producing a high yield of granulated material with a size distribution well adapted to pressing.
  • a further purpose is to provide a method of producing such granulations with a suitable moisture content for pressing.
  • Another purpose is to provide a flexible granulating method particularly adapted to the handling of small amounts of expensive material, but also capable of larger volume production as well.
  • a still further purpose is to provide a method of granulating materials which are readily oxidizable or otherwise chemically active.
  • Still another purpose is to provide a method which may be performed by modifying conventional granulating machines.
  • Fig. l is a flow diagram illustrating the steps involved in the method and,
  • Fig. 2 is an elevational view partly in section schematically illustrating a granulating system in accordance with the invention.
  • the invention provides a method of granulating a fine- 1y dividedmaterial which comprises mixing the material with two liquids having substantially'different rates of volatilization to form a plastic mass, and, removing the more volatile liquid while subdividing the mass into
  • the invention involves subdividing the mass into granules capable of passing through a perforated partition member while simultaneously exposing the mass to a current of air whereby the more volatile liquid is substantially removed and granulation of the material is facilitated.
  • the method is particularly applicable in granulating a ceramic powder, such as uranium oxide or alumina, for subsequent pressing and firing to a dense body and is so illustrated in the flow diagram of Fig. 1.
  • a ceramic powder such as uranium oxide or alumina
  • the ceramic material is combined and thoroughly mixed with a binder and two liquids, such as water and acetone, to form a consolidated mass.
  • the binder, added to impart strength after molding, is not a feature of the present invention, and any compatible binder may be selected.
  • An advantage of the present method is that the total amount of fluid present is not especially critical and may be varied depending on the type of mixing and granulating apparatus used as well as the material itself. For present purposes'it is sufiicient to incorporate only enough liquid to form a pasty, consolidated mass which can be cut into coarse chunks for subsequent granulation, this being easily determined once operating conditions are specified. However, if the material is to be initially wetmilled for example, a larger amount of fluid may be added to forma slurry. Subsequently the slurry must be dried to a pasty or plastic condition for cutting into chunks or otherwise forming coarse granulations.
  • a primary feature of the present invention is that a mixture of two liquids, having widely different rates of volatilization or vapor pressures at constant temperature, is employed in wetting the ceramic powder.
  • the specific example of water and acetone, chosen for illustration, is generally suitable, and illustrates the desired dif ference in volatilization rates.
  • Other similar mixtures might be used as well in accordance with the principles set forth below.
  • other compatible and relatively volatile organic liquids such as simple alcohols, ethers and hydrocarbons may be used with water.
  • each ceramic material has an optimum moisture content for good pressing in the granulated state. This varies with the material but is generally on the order of 1-3% and may easily be determined for any given material and process.
  • a finely'divided material is prepared for granulation by incorporating in the material substantially the amount of moisture or other wetting fluid desired in the granulated product and a relatively larger amount of a more volatile liquid, the total being at least sufficient to form a plastic, consolidated mass. Thereafter substantially all of the more volatile liquid is removed during granulating, leaving the desired amount of moisture in the granules.
  • the plastic mixture of liquid, binder and ceramic powder is coarsely granulated by cutting, beating, milling or other conventional means. With small batches a convenient method involves working the mixture through a ten mesh screen. The coarsegranules thus formed are then introduced into a fine granulating system, such as that illustrated in Fig. 2, for forming 35 to 200 mesh material, and the fine granules collected.
  • the granulating system of Fig. 2 includes a conventional'sieve '10 having a standard twenty mesh screen 12 mounted above a second sieve 14 having'a thirty-five mesh screen 16. Balls 18 are provided to assist in working the material through the screens. Sieves 10 and 14 are in turn mounted over a spacer 22 having a perforated circular coil 24 mounted on its inside wall and extending out to a flexible connection (not shown). Air under controlled low pressure is introduced through perforations 26 of coil 24 and flows upwardly or counter-current to the descending material being granulated. The granules formed in this manner as collected on a collecting cone 28 and funneled into pan 30.
  • the apparatus as shown is particularly designed for operation on a laboratory scale with small lots of material.
  • the principles involved may readily be embodied in larger scale commercial equipment.
  • commercial machines earlier referred to as embodying means for rapidly cutting a moistened mass into granules to pass through a perforated partition, or means for mechanically working the mass through a series of screens, may be modified to perform the present method.
  • Such machines need be modified only to the extent of adding a source of counter current air through their screens or partitions. Tests have shown that the problem of screen blinding is greatly minimized and a higher yield of properly sized granulations is then obtained on such equipment.
  • Example I A solution of 6 cc. of water in 24 cc. of acetone was added to 300 gms. of ballmilled uranium oxide. U0 An addition of one weight percent of a polyethylene glycol type binder was made to the U0 prior to ballmilling this material. The solution and U0 were mixed until the powder was thoroughly wetted. The wetted material was forced through a l0-mesh sieve with a spatula, and the resulting coarse granules introduced at the top of an assembly, such as illustrated in Fig. 2, mounted on a sieve shaker.
  • the assembly consisted, in descending order, of a 20-mesh sieve, a 35-mesh sieve, a spacer containing a copper air-input loop, a collection cone and collecting pan.
  • Two refractory balls were placed on each sieve to aid in working the granules through the sieves.
  • a counter-current air flow on the order of 1000 cc./minute was maintained to volatilize the acetone.
  • the resultant granules, collected in the pan were dry (approximately 1.3% moisture which is beneficial to pressing), free flowing, soft, and had a good size-distribution for pressing.
  • a typical screen analysis follows:
  • Example 11 Ten pounds of alumina powder having an average size of 900 mesh was manually mixed with a solution composed of 2.3 pounds acetone, 0.3 pound of water and 0.1 pound of a polyethylene glycol type binder. The mixture was cut into coarse chunks and rolled througha ten mesh size screen. The coarse granules thus Screen: Weight percent 35+48 37.7 48+65 24.6- -65+100 17.9 -100+1s0 8.3 --150+250 6.0 -250 5.1
  • Example III A mixture of coarse granulated alumina prepared in accordance with Example 11 was treated in identical manner except that the air current was varied slightly so as to employ a seven minute granulating period per lot.
  • the material collected had a moisture'content of 2.08% and a screen analysis as follows:
  • Example IV A 150 gram batch composed of 78.6% A1 and 21.4% U0 by weight was mechanically mixed with 3 cc. H 0, 30 cc. acetone and 2% by weight of a polyethylene .glycol binder to form a consolidated mass in which the acetone content was reduced by evaporation to about 12 cc., thus providing a proper consistency for coarse granulation.
  • the screen analysis was as follows:
  • Example V Weight percent Example V A consolidated mass was prepared as inExample IV from a mixture by weight of 83.2% ZrO and 16.8% U0 The material was granulated under the same conditions and produced the following screen analysis:
  • the present invention provides a simple, flexible method of obtaining a high yield of soft granulated material in optimum condition for subsequent charging to a pressing die or other shaping means. While specific materials and apparatus have. been described for purposes of illustration, it will be appreciated that the invention is not so limited and may be carried out on finely divided materials generally and with any apparatus adaptable to the principles involved.
  • the method of granulating a finely divided ceramic powder which comprises mixing said powder with about the amount of water desired in the granulated product and enough more of an organic liquid that is more volatile than water and inert to said ceramic powder to form a plastic mass of the desired consistency, subdividing the plastic mass into coarse particles, introducing these particles over at least one screen of selected mesh size, causing the material to pass downwardly through said screen while simultaneously exposing the material to a current of air whereby the more volatile organic liquid is substantially removed and granulation of the material is efiected.
  • a method as recited in claim 1 in which the coarse particles are introduced over and passed downwardly through a series of graduated screens of decreasing mesh size while being exposed to a counter-current of air.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Glanulating (AREA)
US655682A 1957-04-29 1957-04-29 Granulation method Expired - Lifetime US2933766A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE567206D BE567206A (zh) 1957-04-29
US655682A US2933766A (en) 1957-04-29 1957-04-29 Granulation method
FR1205593D FR1205593A (fr) 1957-04-29 1958-04-28 Procédé de granulation

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3173883A (en) * 1960-12-06 1965-03-16 Air Prod & Chem Method for producing attrition resistant sorptive alumina particles
US3468985A (en) * 1965-07-08 1969-09-23 Oesterr Studien Atomenergie Method for the production of spherical particles
US3896201A (en) * 1971-08-24 1975-07-22 Saint Gobain Method of processing raw materials for the manufacture of glass
US4786450A (en) * 1985-01-11 1988-11-22 L. P. Weidemann & Sonner I/S Method for the production of building elements particularly suited for use as brick facings
US5364579A (en) * 1989-10-10 1994-11-15 Ecc International Inc. Method for pelletizing calcined clay

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3207824A (en) * 1962-06-22 1965-09-21 Wisconsin Alumni Res Found Process for preparing agglomerates
DE3132303A1 (de) * 1981-08-17 1983-02-24 Bayer Ag, 5090 Leverkusen Verfahren zur herstellung staubarmer anorganischer pigmentgranulate mit enger kornverteilung
DE3242747A1 (de) * 1981-12-23 1983-08-25 Degussa Ag, 6000 Frankfurt Verfahren zur herstellung anorganischer pigmente

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1598933A (en) * 1919-12-31 1926-09-07 Read Alexander Mahaffey Pulverizing mill
US1614364A (en) * 1923-02-24 1927-01-11 Procedes Hidoux Soc D Expl Des Combined drying and grinding machine for clay and other plastic materials
US2007742A (en) * 1934-03-10 1935-07-09 Brown Leslie Process of making ceramic granules
US2065762A (en) * 1931-02-03 1936-12-29 Celanese Corp Production of finely divided material
US2545441A (en) * 1947-04-22 1951-03-20 Edward P Barrett Method for forming glomerules
US2627642A (en) * 1950-03-17 1953-02-10 Raymond G Osborne Jr Method of vesiculation
US2641044A (en) * 1949-10-24 1953-06-09 Phillips Petroleum Co Process for manufacturing mullitecontaining refractories
US2693018A (en) * 1951-06-20 1954-11-02 Univ Ohio State Res Found Process of forming lightweight aggregate
US2834991A (en) * 1954-01-15 1958-05-20 Goodyear Tire & Rubber Method of preparing compounding ingredients for rubber

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1598933A (en) * 1919-12-31 1926-09-07 Read Alexander Mahaffey Pulverizing mill
US1614364A (en) * 1923-02-24 1927-01-11 Procedes Hidoux Soc D Expl Des Combined drying and grinding machine for clay and other plastic materials
US2065762A (en) * 1931-02-03 1936-12-29 Celanese Corp Production of finely divided material
US2007742A (en) * 1934-03-10 1935-07-09 Brown Leslie Process of making ceramic granules
US2545441A (en) * 1947-04-22 1951-03-20 Edward P Barrett Method for forming glomerules
US2641044A (en) * 1949-10-24 1953-06-09 Phillips Petroleum Co Process for manufacturing mullitecontaining refractories
US2627642A (en) * 1950-03-17 1953-02-10 Raymond G Osborne Jr Method of vesiculation
US2693018A (en) * 1951-06-20 1954-11-02 Univ Ohio State Res Found Process of forming lightweight aggregate
US2834991A (en) * 1954-01-15 1958-05-20 Goodyear Tire & Rubber Method of preparing compounding ingredients for rubber

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3173883A (en) * 1960-12-06 1965-03-16 Air Prod & Chem Method for producing attrition resistant sorptive alumina particles
US3468985A (en) * 1965-07-08 1969-09-23 Oesterr Studien Atomenergie Method for the production of spherical particles
US3896201A (en) * 1971-08-24 1975-07-22 Saint Gobain Method of processing raw materials for the manufacture of glass
US4786450A (en) * 1985-01-11 1988-11-22 L. P. Weidemann & Sonner I/S Method for the production of building elements particularly suited for use as brick facings
US5364579A (en) * 1989-10-10 1994-11-15 Ecc International Inc. Method for pelletizing calcined clay

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FR1205593A (fr) 1960-02-03
BE567206A (zh)

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