WO2006115497A1 - Procedes et systemes permettant d’ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d’un melange - Google Patents

Procedes et systemes permettant d’ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d’un melange Download PDF

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Publication number
WO2006115497A1
WO2006115497A1 PCT/US2005/014504 US2005014504W WO2006115497A1 WO 2006115497 A1 WO2006115497 A1 WO 2006115497A1 US 2005014504 W US2005014504 W US 2005014504W WO 2006115497 A1 WO2006115497 A1 WO 2006115497A1
Authority
WO
WIPO (PCT)
Prior art keywords
discharge apparatus
wga
gypsum
aqueous dispersion
accelerator
Prior art date
Application number
PCT/US2005/014504
Other languages
English (en)
Inventor
James R. Wittbold
W. David Song
Original Assignee
United States Gypsum Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to PCT/US2005/014504 priority Critical patent/WO2006115497A1/fr
Priority to CNA2005800496010A priority patent/CN101184703A/zh
Priority to MX2007012681A priority patent/MX2007012681A/es
Priority to AU2005331094A priority patent/AU2005331094A1/en
Priority to NZ561843A priority patent/NZ561843A/en
Priority to JP2008508810A priority patent/JP2008539103A/ja
Application filed by United States Gypsum Company filed Critical United States Gypsum Company
Priority to EP05739963A priority patent/EP1874705A1/fr
Priority to CA002602053A priority patent/CA2602053A1/fr
Priority to BRPI0520228-0A priority patent/BRPI0520228A2/pt
Publication of WO2006115497A1 publication Critical patent/WO2006115497A1/fr
Priority to IL186156A priority patent/IL186156A0/en
Priority to NO20075073A priority patent/NO20075073L/no

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B17/00—Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping
    • B28B17/02—Conditioning the material prior to shaping
    • B28B17/023—Conditioning gypsum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/04—Supplying or proportioning the ingredients
    • 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
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • 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
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028—Aspects relating to the mixing step of the mortar preparation
    • C04B40/0039—Premixtures of ingredients
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B19/00—Machines or methods for applying the material to surfaces to form a permanent layer thereon
    • B28B19/0092—Machines or methods for applying the material to surfaces to form a permanent layer thereon to webs, sheets or the like, e.g. of paper, cardboard
    • 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
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/10—Accelerators; Activators
    • C04B2103/12—Set accelerators
    • 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00612—Uses not provided for elsewhere in C04B2111/00 as one or more layers of a layered structure
    • C04B2111/0062—Gypsum-paper board like materials

Definitions

  • Set gypsum (calcium sulfate dihydrate) is a well-known material that is included commonly in many types of products, such as gypsum board employed in typical drywall construction of interior walls and ceilings of buildings.
  • gypsum-containing board is prepared by forming a mixture of calcined gypsum, that is, calcium sulfate hemihydrate and/or calcium sulfate anhydrite, and water, as well as other components, as desired.
  • the mixture typically is cast into a pre-determined shape on the surface of a conveyor or in a tray.
  • the calcined gypsum reacts with water to form a matrix of crystalline hydrated gypsum or calcium sulfate dihydrate.
  • the desired hydration of the calcined gypsum is what enables the formation of an interlocking matrix of set gypsum crystals, thereby imparting strength to the gypsum structure in the gypsum-containing product. Mild heating can be used to drive off unreacted water to yield a dry product.
  • Gypsum mixers and methods of producing gypsum products are described, for example, in U.S. Patent Nos: 1 ,767,791 ; 2,253,059; 2,346,999; 4,183,908; 5,683,635; 5,714,032; and 6,494,609.
  • Accelerator materials are commonly used in the production of gypsum products to enhance the efficiency of hydration and to control set time. Accelerators are described, for example in U.S. Patent Nos: 3,573,947; 3,947,285; 4,054,461 ; and 6,409,825.
  • Some accelerators include finely ground dry calcium sulfate dihydrate, known as "gypsum seeds.” The gypsum seeds enhance nucleation of the set gypsum crystals, thereby increasing the crystallization rate thereof.
  • accelerators have been added to the same mixer chamber as that used to combine water with calcined gypsum.
  • accelerator While addition of accelerator to the mixer has the advantage of mixing the accelerator well and evenly throughout the water and calcined gypsum mixture, the accelerator can also cause the gypsum to begin setting prematurely. Premature setting can cause the mixer to clog, can cause damage to the mixer, limits efficiency, and necessitates more frequent mixer cleaning. Mixer cleaning requires shutting down a board line with a serious detriment to productivity. Although additives including retarders have been used in the mixer to combat premature setting, such additives contribute additional costs and considerations.
  • a method of introducing a wet gypsum accelerator (WGA) to a post-mixer aqueous dispersion of calcined gypsum is provided.
  • An aqueous dispersion of calcined gypsum is formed in a mixer chamber of a stucco mixer and discharged into a discharge apparatus.
  • WGA is introduced into the aqueous dispersion within the discharge apparatus.
  • a method of introducing a high viscosity production additive to a post-mixer aqueous dispersion of calcined gypsum is provided.
  • An aqueous dispersion of calcined gypsum is formed in a mixer chamber and discharged into a discharge apparatus.
  • the high viscosity production additive is introduced into the aqueous dispersion within the discharge apparatus.
  • the ratio of the viscosity of the high viscosity production additive to the aqueous dispersion is between about 10:1 to about 2:1.
  • the system includes at least a source of WGA; a delivery device; a mixer for forming an aqueous dispersion of calcined gypsum; a discharge apparatus operatively associated with an outlet of the mixer-the source, delivery device and the discharge apparatus operatively associated with each other.
  • the present invention has particular utility in the preparation of gypsum board such as wallboard or ceiling tile.
  • the high viscosity production additive such as WGA
  • the dispersion is deposited onto a moving coversheet.
  • a second coversheet is applied to the deposited contents prior to drying.
  • a second coversheet is not employed.
  • Figure 1 shows a schematic plan view of a system for adding a high viscosity gypsum additive to a post-mixer aqueous dispersion of calcined gypsum.
  • Figure 2 shows a schematic cross-sectional view of part of the system shown in Fig. 1 comprising an injection ring with multiple injection ports.
  • Figure 3 shows a variation on the schematic cross-sectional view of Fig. 2 incorporating a tee junction.
  • Figure 4 shows a schematic plan view of a variation on the system shown in Fig. 1.
  • Figure 5 shows a partial perspective view of a mixer and discharge apparatus.
  • Figure 6 shows a perspective view of a first portion of a mixer discharge apparatus system.
  • Figure 7 shows a perspective view of a second portion of a mixer discharge apparatus system.
  • Figure 8 shows a schematic plan view of the system depicted in Figs. 6 and 7.
  • Figure 9 shows a schematic plan view of a variation of the system depicted in Fig. 8.
  • Figure 10 shows a schematic plan view of a variation of the system depicted in Fig. 9.
  • the present invention is premised, at least in part, on the surprising discovery that a high viscosity production additive such as wet gypsum accelerator can be added to a relatively low viscosity aqueous dispersion calcined gypsum in a discharge apparatus downstream of a stucco mixer, and still achieve adequate mixing to yield a gypsum product with acceptable set time.
  • the discharge apparatus according to the invention does not require a separate power source in order to mix the high viscosity production additive with the aqueous dispersion of calcined gypsum as the dispersion passes from the stucco mixer through the discharge apparatus.
  • a system 12 for adding a high viscosity production additive to a post-mixer aqueous dispersion of calcined gypsum comprises a high viscosity production additive source 15, which in some embodiments can hold wet gypsum accelerator (WGA). While a single source 15 is shown that is for illustrative purposes only as multiple sources can be provided.
  • the system 12 also comprises a delivery device 18; which can comprise a pump, and in some embodiments is a positive displacement pump. Appropriate pumps for use in the systems of the invention are discussed in more detail in relation to the methods of the invention.
  • the system 12 further comprises a mixer 21 for producing an aqueous dispersion of calcined gypsum.
  • the mixer 21 has an interior or mixing chamber 24 from which is provided at least one outlet 27. Extending from the mixer outlet 27 is a discharge apparatus 30 through which the aqueous gypsum slurry can flow and ultimately exit at an outlet 31.
  • the outlet comprises a boot.
  • a boot is appropriate for use on the discharge apparatus used for depositing the main field slurry-as opposed to the densified layer slurry.
  • the outlet is provided as a conduit such as hose.
  • a conduit or hose outlet is appropriate for a densified layer discharge apparatus.
  • the source 15, delivery device 18, and discharge apparatus 30 are operatively connected so as to permit flow of WGA and/or other production additive.
  • the connectivity is provided by a transfer line 33, which in turn can have multiple segments, for example, 36, 39, depending on the embodiment.
  • the transfer line 33 can have a pressure meter 42 for use in measuring the pressure of the production additive in the transfer line.
  • the transfer line 33 is associated with an injection ring 45.
  • the injection ring 45 comprises at least one injection port 48 through which the transfer line 33 can feed. More detailed views of the injection ring and associated elements are shown in Figs. 2 and 3. While injection rings are discussed in the context of both systems and methods of the present invention, other means of injection can be employed in addition or in the alternative to an injection ring.
  • a needle on a transfer line can be used for transfer into the discharge apparatus.
  • a nipple is provided in the discharge apparatus to allow transfer into the apparatus.
  • the system 12 can further incorporate one or more additional discharge apparatus, for example, 130 and 230.
  • additional discharge apparatuses for example, 130 and 230
  • Delivery devices 118, 218, mixer outlets, 127, 227, discharge apparatus outlets, 131 , 231 , transfer lines 133, in some embodiments including 136 and 139, 233, in some embodiments including 236 and 239, pressure gauges 142, 242, injection rings 145, 245, injection ports 148, 248, are operatively associated in a manner analogous to those described for the discharge apparatus 30 and associated elements. While Fig.
  • Fig. 1 shows a system 12 with three discharge apparatuses 30, 130, and 230, and associated elements, the system 12 can have as few as one discharge apparatus 30 with no upper limit contemplated on the number of additional apparatuses.
  • Fig. 2 shows an embodiment in which the transfer line 33 comprises an udder, manifold, or other device with branching capability 51 that splits the transfer line 33 into a plurality of branch lines 53, 57, and 60. Three branch lines are shown for illustrative purposes only.
  • the injection ring 45 of Fig. 2 is shown with a plurality of injection ports 48, 48', and 48", the injection ring 45, but again that number is shown for illustrative purposes only.
  • the branch lines 53, 57, and 60 feed into injection ports 48, 48', and 48" respectively.
  • additional injection rings for example, 145, 245, as depicted in Fig. 1 , can be present and incorporate the aforementioned features.
  • Fig. 3 shows a variation on the embodiment shown in Fig. 2, which incorporates a tee 63 that allows mixing of the production additive from the source 15 with one or more additional production additives of no particular viscosity prior to injection into the discharge apparatus 30.
  • the tee 63 comprises a junction 66 on which a first additive 69 and a second additive 72 converge. While Fig. 3 only shows a tee 63 for one of the injection ports 48, that representation is for illustrative purposes only. Any number of the injection ports can have a tee 63 associated with them.
  • Fig. 4 shows a system 112, which is a variation on that shown in Fig. 5.
  • System 112 again comprises a production additive source 15 from which a high viscosity production additive, for example, WGA, is fed to the respective discharge apparatuses 30, 130, and 230.
  • the system 112 uses a single delivery device 18, for example, a pump, and a udder, manifold, or other device with branching capability 75 to split the transfer line 33 into multiple branch lines, for example, 78, 81 , and 84, dividing from each other at 87.
  • the branch lines for example, 78, 81 , and 84, can incorporate valves or similar devices 79, 82, and 85 to control flow to the branch lines, and such valves can also or in the alternative be associated with the branching device 75.
  • Each branch line eventually leads to an injection ring 45, 145, and 245 on the respective discharge apparatuses 30, 130, and 230.
  • FIG. 5 shows a discharge apparatus 430, which is one embodiment for the discharge apparatus 30, 130, 230, etc.
  • the discharge apparatus 430 also displays a number of different elements and attributes that can be comprised by and/or operatively associated with a discharge apparatus generally.
  • the discharge apparatus comprises a gate 425 with gate opening 426, a series of hose sections 432, 434 and 438, a cage valve 440, and two injection rings 45, 445 with injection ports 48, 448, and an outlet 431.
  • the gate 425 acts as an adapter that allows the discharge apparatus' conduit to attach to the mixer 21 at the mixer outlet 27.
  • the gate 425 is shown with an optional injection port 548.
  • the injection ports 48, 448, and 548 are examples of possible locations for entry of WGA, foam, or other production additive.
  • the rings 45, 445 and gate 425 can be configured to have multiple injection ports, for example, as illustrated in Figs. 2 and 3.
  • the hose section 434 separating the rings 45, 445 is about 15 to about 16 inches long.
  • the transfer line 33 or other transfer lines can be connected at any of the injection ports.
  • the positioning of the cage valve 440 can be varied along the length of the discharge conduit 430 and can allow for control of flow in the discharge conduit.
  • the discharge apparatuses and systems of the invention can incorporate elements or subsystems described in co-owned U.S. Patent No. 6,494,609. [0028] Additional systems of the invention are described herein in regards to the below examples. While those systems are discussed in the context of the examples, they are not limited to the uses described in those examples. [0029] The methods of the present invention can utilize one or more systems, subsystems, and elements as described herein, for example, as described in respect to the figures. However, the methods can employ other appropriate systems, subsystems, and elements.
  • the additional accelerant can be added in the aqueous dispersion of calcined gypsum mixer or outside of that mixer, that is, in the discharge apparatus.
  • potash in granule and/or powder form, is used as an additional accelerator.
  • WGA wet gypsum accelerator
  • a high viscosity additive can comprise one or more additional additives that by themselves can have a low viscosity, provided that when combined with the high viscosity additive the viscosity of the high viscosity additive remains high.
  • WGA and other high viscosity additives of the invention typically have a viscosity in the range of between about 3000 to about 5000 centipoises. In some embodiments, the range will be between about 2000 to about 10000 centipoises. In some embodiments, the range will be between about 2500 to about 9500 centipoises.
  • the range will be between about 3000 to about 9000 centipoises. In some embodiments, the range will be between about 3500 about to about 8500 centipoises. In some embodiments, the range will be between about 4000 to about 8000 centipoises. In some embodiments, the range will be between about 4500 to about 7500 centipoises. In some embodiments, the range will be between about 5000 to about 7000 centipoises. In some embodiments, the range will be between about 5500 to about 6500 centipoises. In some embodiments, the range will be between about 2500 to about 5500 centipoises.
  • the range will be between about 2750 to about 5250 centipoises. In some embodiments, the range will be between about 3250 to about 4750 centipoises. In some embodiments, the range will be between about 3500 to about 4500 centipoises. In some embodiments, the range will be from about 3750 to about 4250 centipoises. In some embodiments, the viscosity of the wet gypsum accelerator is about 1000 centipoises or greater and about 5000 centipoises or less. In some embodiments, the viscosity of the wet gypsum accelerator is about 2000 centipoises to about 4000 centipoises.
  • Viscosity measurements described herein are reflective of measurements taken at ambient temperatures.
  • Representative WGA for use in the present invention is described in U.S. Patent 6,409,825, as well as in concurrently filed and co-owned application "WET GYPSUM ACCELERATOR AND METHODS, COMPOSITION, AND PRODUCT RELATING THERETO" (Attorney Reference No. 234912), U.S.
  • the viscosity of the high viscosity additive used can be limited by the constraints of the system employed, for example, whether the pump employed is powerful enough to allow delivery of the additive to the discharge apparatus.
  • One of skill in the gypsum art will be able to identify the appropriate type of WGA for a given gypsum application based on the teachings of the present invention and the knowledge available in the art.
  • One aspect of the invention provides a method of introducing a wet gypsum accelerator (WGA) to a post-mixer aqueous dispersion of calcined gypsum, in which the method comprises forming an aqueous dispersion of calcined gypsum in a mixer chamber; transferring the aqueous dispersion into a discharge apparatus; and introducing the WGA into the aqueous dispersion within the discharge apparatus.
  • WGA wet gypsum accelerator
  • the WGA comprises calcium sulfate dihydrate, water, and at least one phosphorous additive selected from the group consisting of: (a) an organic phosphonic compound; (b) a phosphate-containing compound; and (c) a mixture of (a) and (b).
  • the ground product of the WGA comprises calcium sulfate dihydrate and has a median particle size of about 5 ⁇ m or less. The ground product is the result of the wet grinding used to produce WGA. This process is discussed in co-owned U.S. Patent No. U.S.
  • the ground product of the WGA has a median particle size of about 0.5 ⁇ m to about 2 ⁇ m. In some embodiments, the ground product of the WGA has a median particle size of about 1 ⁇ m to about 1.7 ⁇ m. In some embodiments, the ground product of the WGA has a median particle size of about 1 ⁇ m to about 1.5 ⁇ m.
  • the phosphorous additive is present in an amount of about 0.1 % to about 10% by weight of said accelerator.
  • the ground product of the WGA is substantially amorphous.
  • the phosphorous additive is a mixture of at least one organic phosphonic compound and at least one phosphate-containing compound, wherein the organic phosphonic compound is present in an amount of from about 0.05% to about 9.95% by weight of said accelerator, and wherein the phosphate-containing compound is present in an amount of from about 0.05% to about 9.95% by weight of said accelerator.
  • the WGA comprises an organic phosphonic compound selected from the group consisting of aminotri (methylene-phosphonic acid), aminotri (methylene-phosphonic acid), 1-hydroxyethylidene-1 ,1-diphosphonic acid, 1-hydroxyethylidene-1 ,1-diphosphonic acid, diethylenetriamine penta(methylene phosphonic acid), diethylenetriamine penta(methylene phosphonic acid), hexamethylene diamine tetra(methylene phosphonic acid), hexamethylene diamine tetra(methylene phosphonic acid), a pentasodium salt, trisodium salt, tetrasodium salt, sodium salt, ammonium salt, potassium salt, calcium salt, or magnesium salt of any of the foregoing acids, and combinations thereof.
  • the WGA comprises a phosphate-containing compound selected from the group consisting of orthophosphates, polyphosphates, and combinations thereof.
  • the WGA comprises a phosphate- containing compound selected from the group consisting of tetrapotassium pyrophosphate, sodium acid pyrophosphate, sodium tripolyphosphate, tetrasodium pyrophosphate, sodium potassium tripolyphosphate, sodium hexametaphosphate salt having from 6 to about 27 phosphate units, ammonium polyphosphate, sodium trimetaphosphate, and combinations thereof.
  • the WGA comprises a mixture of about 0.5% pentasodium salt of aminotri(methylene phosphonic acid) by weight of the calcium gypsum dihydrate and about 0.5% sodium trimetaphosphate by weight of the calcium gypsum dihydrate.
  • the solids content of the WGA can be modified, as desired, depending on the particular application.
  • the viscosity of the WGA can be modified, depending on the particular application.
  • the WGA can be diluted with water before it is used.
  • the WGA comprises a solids content comprising calcium sulfate dihydrate in an amount of at least about 20% by weight of said accelerator.
  • the solids portion comprising calcium sulfate dihydrate of the accelerator is present in an amount of from 35% to about 45% of said accelerator, and water is present in an amount of from about 55% to about 65% by weight of said accelerator.
  • the versatility of the WGA of the present invention will also be understood by those skilled in the art.
  • the WGA of the present invention when added to a mixture comprising calcined gypsum and water used to form an interlocking matrix of set gypsum, allows for a Time to 50% Hydration of calcined gypsum of about 6 minutes or less. In some embodiments, when added to a mixture comprising calcined gypsum and water used to form an interlocking matrix of set gypsum, the WGA allows for a Time to 50% Hydration of calcined gypsum of about 5 minutes or less. Desired setting times can depend upon various factors, including the solids content of the WGA, the viscosity of the WGA, and the particle size of the solids of the WGA. When the WGA is used in the manufacture of gypsum board, other factors which can affect setting times include line speed, length of the line, gypsum characteristics and the like, as will be appreciated by one of ordinary skill in the art.
  • the WGA and/or other high viscosity additive is introduced into the relatively low viscosity aqueous dispersion of calcined gypsum contained with the discharge apparatus 30.
  • the aqueous dispersion has a viscosity of between about 700 to about 1200 centipoises. In some embodiments, the dispersion has a viscosity of between about 100 to 1750 centipoises. In some embodiments, the dispersion has a viscosity of between about 200 to 1650 centipoises. In some embodiments, the dispersion has a viscosity of between about 300 to 1550 centipoises.
  • the dispersion has a viscosity of between about 400 to 1500 centipoises. In some embodiments, the dispersion has a viscosity of between about 450 to 1450 centipoises. In some embodiments, the dispersion has a viscosity of between about 500 to 1400 centipoises. In some embodiments, the dispersion has a viscosity of between about 550 to 1350 centipoises. In some embodiments, the dispersion has a viscosity of between about 600 to 1300 centipoises. In some embodiments, the dispersion has a viscosity of between about 650 to 1250 centipoises.
  • the dispersion has a viscosity of between about 750 to 1150 centipoises. In some embodiments, the dispersion has a viscosity of between about 800 to 1000 centipoises. In some embodiments, the dispersion has a viscosity of between about 850 to 950 centipoises.
  • the dispersion has a viscosity of between about 875 to 925 centipoises.
  • the WGA and/or other high viscosity production additive to be introduced into the aqueous dispersion of calcined gypsum in the discharge apparatus according to the present invention can also be expressed in terms of a ratio.
  • the WGA can have a viscosity approximately four times that of the aqueous dispersion.
  • the WGA has a viscosity approximately three times that of the aqueous dispersion.
  • Applicable ratios include 10:1 , 9:1 , 8:1 , 7:1 , 6:1 , 5:1 , 4.5:1 , 4.25:1 , 4.1 , 3.75:1, and 3.5:1 , 3.25:1 , 3:1 , 2.75:1 , 2.5:1 , 2.25:1 , 2:1 , as well as ratios intermediate to said ratios.
  • a method in accordance with the present invention comprises delivering a high viscosity production additive such as WGA from a source 15 to a discharge apparatus 30 where the additive is introduced into an aqueous dispersion of calcined gypsum that has been discharged from a gypsum mixer, for example, a pin mixer, multipass mixer, pinless mixer, or other mixers that can be used to make aqueous gypsum dispersions wherein the aqueous dispersion had been mixed.
  • a gypsum mixer for example, a pin mixer, multipass mixer, pinless mixer, or other mixers that can be used to make aqueous gypsum dispersions wherein the aqueous dispersion had been mixed.
  • the WGA is generally moved from the source 15 to the discharge apparatus 30 with the assistance of one or more delivery devices, for example, 18, 118, 218.
  • the delivery device is a pump.
  • the pump is a positive displacement pump, but other pump types can be used in addition or in the alternative, for example, a centrifugal pump.
  • suitable positive displacement pumps include progressive cavity, gear, and peristaltic pumps.
  • the pressure of the slurry entering the discharge apparatus should be maintained at a pressure greater than that of the contents of the discharge apparatus so as to minimize back pressure and allow efficient transfer of the HRA slurry.
  • the pressure in the discharge apparatus is between about 5 and about 15 p.s.i.
  • the pressure of the WGA in the transfer line 33 between the source 15 and discharge apparatus 30 can be measured using a pressure gauge 42. However, use of such a gauge is not necessary if the pump employed is self- regulating.
  • the gauge has a range of 0-30 p.s.i. [0039]
  • the WGA can be discharged into the discharge apparatus 30 through an injection port 48, which can be associated with an injection ring 45.
  • the WGA is split into multiple branches to allow for multiple entries into the discharge apparatus 30. Such multiple entries can be achieved by providing multiple inlets, for example, 48, 48', and 48" in the injection ring 45.
  • the WGA is combined with one or more additional additives, for example, foam, before being introduced into the aqueous dispersion of the discharge apparatus 30.
  • Such combining can be accomplished using a tee 63 formed by entry of WGA or other high viscosity additive 69 and another additive irrespective of viscosity 72.
  • the WGA and one or more additional additives are combined approximately three inches from the point of injection into the discharge apparatus.
  • the WGA is transferred into the discharge apparatus downstream of a pinch valve operatively associated with the discharge apparatus.
  • multiple discharge apparatuses can be implemented.
  • second and third discharge apparatuses that is, densified layer extractors 130, 230 can be provided.
  • second and third discharge apparatuses that is, densified layer extractors 130, 230 can be provided.
  • second and third discharge apparatuses that is, densified layer extractors 130, 230
  • only a single densified layer is applied.
  • a separate delivery devices 18, 118, and 218 are utilized for transfer of the WGA from the source 15 to the discharge apparatuses 30, 130, and 230.
  • a delivery device 18 is used for the discharge apparatus 30, and a delivery device 118 is used for the discharge apparatuses 130 and 230.
  • the WGA can split into branch transfer lines using an udder, tee, manifold, or other device allowing branching of the transfer line. Control of WGA flow into particular branch lines can be controlled using a valve or other element of like function.
  • WGA and/or other high density production additive is generally introduced to the post-mixer aqueous dispersion in a stream perpendicular to the flow of the dispersion in the discharge apparatus.
  • other orientations of WGA introduction are also possible.
  • the WGA is introduced into the discharge apparatus closer to the mixer outlet 27 than the discharge outlet 31.
  • the introduction occurs from about 2.5 inches to 3 inches from the mixer outlet 27.
  • the introduction occurs about 1 inch from the mixer outlet.
  • moving the introduction of the WGA downstream in the discharge apparatus will serve to delay setting acceleration.
  • each densified layer discharge apparatus 130, 230 can comprise and/or be operatively associated with one or more of the following: a hose and a ring (for example, 145, 245).
  • the percentage of WGA to provide a proper set is dependent on the amount of aqueous slurry that is being applied to the densified layer of the board.
  • the aqueous dispersion from the mixer 21 is being applied to a first, for example, bottom, densified layer, then preferably approximately 10% of the WGA is directed to the bottom densified layer through the bottom discharge apparatus 130. If a second, for example, top, densified layer is being utilized, the proportion of WGA would again preferably approximately match the percentage of gypsum slurry being applied to the top densified layer. Percentages of gypsum slurry from the mixer 21 generally range from about 5% to about 20%.
  • the terms top and bottom, as well as face and back and other equivalent terms, are relative terms in respect to which orientation of the gypsum product one is referring to.
  • bottom refers to a first paper, that is, a cover sheet, that travels beneath the gypsum mixer and the densified layer that is applied to that first paper.
  • Top refers to a second paper that is applied after addition of the gypsum slurry through the main discharge apparatus 30 to the bottom paper, as well as the densified layer applied to the second paper.
  • a dispersant is added to the discharge apparatus such as lignin, napthelene sulfate or other suitable dispersant.
  • the systems and method of the present invention have the benefit of delaying setting of an aqueous dispersion of calcined gypsum by delaying the introduction of WGA until after the dispersion has left the stucco mixer 21.
  • the methods allow for addition of less water to the stucco mixer resulting in a lower water-stucco ratio, as a result of less setting in the mixer because of the absence of accelerator in the mixer interior 24.
  • Methods and systems are also contemplated for introducing the WGA directly into the mixer 21 in addition to introduction into the discharge apparatus.
  • EXAMPLE 1 ADDITION OF WGA TO THE DISCHARGE APPARATUS
  • WGA used for the trial was of the following formulation: 0.5% pentasodium salt and 0.5% sodium trimetaphosphate, and 42% solids by weight of the WGA and 58% water by weight of the WGA.
  • a trial was performed in which WGA was introduced in the main gate of the main discharge apparatus and the back densified layer discharge apparatus. As a comparison, the WGA was also injected into an emergency water port inside the pin mixer. The WGA successfully set the board uniformly when added inside or "outside" the mixer.
  • WGA usage did not change whether it was being introduced inside or outside the mixer. In both of these cases, no heat resistant accelerator (HRA) was being added to set the board, although HRA was used during an initial start-up period. HRA used during the trial was a mixture of 99.5% gypsum/0.5% sugar milled to fine particle size in a dry condition. Typical gypsum board paper was employed for the trial.Table 1 summarizes the trial conditions and records the accelerator usage (HRA and WGA) and water usage Units in Table 1 , where applicable, are in Ibs/MSF. The stucco used in the trial was 1235 Ibs./MSF. THE WGA% solid was 42%.
  • HRA heat resistant accelerator
  • the system 612 schematically illustrated in Figs. 6, 7, and 8 was used for the trial. Beneath the system is a first paper 614 to which the aqueous dispersion of calcined gypsum was applied. After the gypsum was applied to the paper 614, a second paper was applied to form wallboard. A densified layer was only applied to the bottom paper. In other embodiments, the densified layer can be applied to just the top paper, or to both top and bottom papers.
  • the system 612 comprises a mixer 621 with an interior 624 and outlets 627, 727. Gates 625, 825 of discharge apparatuses 630, 730 were operatively associated with the outlets 627, 727.
  • operatively associated with the mixer 621 was a main field discharge apparatus 630 and a densified layer discharge apparatus 730.
  • Each discharge apparatus 630, 730 was supplied by separate WGA sources 15, 615 respectively.
  • Separate transfer lines 633, including sections 636 and 639, 733, including 736 and 739, and pumps 18, 618 were used to transfer the WGA to the apparatuses 630, 730.
  • the mixer 621 comprised an emergency water port 622 through which WGA was transferred during certain periods of the trial.
  • the mixer 621 and discharge apparatus 630 were operatively associated with the WGA source 15 through branch transfer lines 638, 639 respectively. Control valves 23, 623, were provided on the branch transfer lines 638, 639 respectively to allow for control of WGA transfer to the mixer 621 and discharge apparatus 630.
  • the main mixer gate 625 is operatively associated with a first flange 671 and fitted against a second flange 673 operatively associated with a first hose section 634 of the discharge apparatus 630.
  • WGA was supplied from the source 15 and transfer was assisted using a MoynoTM pump, which is a positive displacement pump. WGA was injected into a 1 and 3/4" interior diameter (ID) flange 673 with three 3/8" ID ports 648, 648', and 648".
  • the ports of flange 673 were supplied by three branch lines 653, 657, and 660 provided as three 1/2" hoses branching from an udder 51 , in a manner analogous to what is shown in Fig. 2 for ring 45.
  • a pressure gauge 642 was not used during the trial, such a gauge can be supplied on one of the branch lines, for example, 53, just before injection into the flange 673. In some embodiments, a 0-30 p.s.i. gauge is employed.
  • the arrow 654 indicates that the branch lines from the udder ultimately associate with the flange 673. In other embodiments, the 671, 673 flange set-up can be replaced with an analogous injection ring.
  • the foam ring 745 included ports 748, 748', 748", and 748'" supplied with foam from a foam source using foam transfer lines one of which was supplied with a pressure gauge 742.
  • the transfer lines feeding the ports were 753, 757, 760, and 761 respectively.
  • the foam ring was supplied with foam and water using an arrangement analogous to that shown in Fig. 2 for ring 45. While in other embodiments, the foam ring 745 is located where the second flange 673 is, for the trial, the foam ring 745 was moved 13" inches farther down the discharge apparatus 630 with a 2" ID TygonTM hose 634 connecting the two together.
  • the foam ring 745 was a 1 and 3/4" ID to 2" ID expanding foam ring. From that point, 2 and 1/4" ID TygonTM hose 638 approximately 9 feet long led into a single leg boot 631.
  • the densified layer discharge apparatus 730 terminates at 731.
  • the line 790 carried sodium trimetaphosphate.
  • the back densified layer discharge apparatus 730 WGA was pumped from a separate tank 615 and injected into the gate 825 using a SeepexTM pump 618, which is a progressive cavity pump.
  • the hose 639 was appropriately sized for entry into the gate 825 at port 826, close to which was provided a pressure gauge 842, for example, 0-30 p.s.i., to measure WGA pressure entering the port 826.
  • WGA usage for the densified layer was designed to be approximately 10% of the main field slurry WGA usage.
  • the WGA was injected into a 1/4" pipe that in other embodiments can be the point where foam and water are added to the extractor.
  • a 1"ID foam injection ring 845 was installed approximately 10" inches downstream of where the WGA was being injected into the discharge apparatus 730.
  • the injection ring 845 included an injection port 848 to which a transfer line 834 supplied foam and water.
  • this trial used a WGA with an efficiency of 60 Ibs/MSF, where MSF stands for thousand square feet.
  • This relatively low efficiency was addressed by using a manufacturing procedure that evaluates viscosity versus grinding time in a horizontal media mill from Premier. This manufacturing procedure involved the use of a targeted viscosity as an indication of when to cease grinding — as opposed to grinding mill load or a constant grinding time.
  • the viscosity can be measured by using any commercially available viscometer, for example, one produced by Brookfield.
  • Any commercially available viscometer for example, one produced by Brookfield.
  • the development of the relationship between WGA efficiency and its viscosity is discussed in in U.S. Patent 6,409,825, as well as in concurrently filed and co-owned application "WET GYPSUM ACCELERATOR AND METHODS, COMPOSITION, AND PRODUCT RELATING THERETO" (Attorney Reference No.
  • WGA efficiency was measured with the same procedure as the one used to determine HRA efficiency, which involves evaluating the rate of the hydration using a standard stucco and the WGA or HRA of interest.
  • climate stable accelerator CSA
  • the rate of hydration of the sample is compared with the rate of hydration using the same standard stucco and a standard accelerator. If the WGA or HRA is more effective in accelerating the hydration process compared to the standard accelerator, a efficiency of more than 100 will be given.
  • the rate of hydration is typically determined by measuring the temperature profile against time in a fully insulated environment because the hydration process is an exothermic reaction.
  • the trial was conducted on 1/2" production at 180 feet per minute.
  • the introduction of WGA outside the mixer trial was conducted for 1-3/4 hours, trials of shorter or longer duration are also possible.
  • the introduction of WGA inside the mixer was conducted for approximately 10 minutes before a small lump caused a paper break, which forced shutdown of the boardline.
  • the lump may have been the result of changing from the outside of the mixer configuration to inside the mixer configuration, a change that caused the port from the densified layer discharge apparatus to become plugged.
  • Stiffening rates were approximately 21 seconds for the back densified layer and 30 seconds for the main slurry. Hardness tests using a USG durometer tester just before the knife measured 67 to 70. When a board knife sample was checked off line, the hardness across the board was very uniform. The boards made during the trial did not show any paper-densified layer bond problem. Nail pull values were typical of board made with HRA.
  • On-line hydration Temperature Rise measuring System (TRS) during WGA trial was as follows: At 15:17, time to 50% hydration was 4.1 minutes on densified layer, 52.8% hydration at knife. At 15:27, time to 50% hydration was 3.6 minutes on main slurry, 58.6% hydration at knife. At 15:38, time to 50% hydration was 3.9 minutes on densified layer, 54.1% hydration at knife. At 15:51, time to 50% hydration was 3.8 minutes on main slurry. 57.4% hydration at knife. EXAMPLE 2
  • a single WGA source 15 is used to supply both discharge apparatuses 630, 730, and no WGA is supplied to the mixer 24.
  • a system 712 as shown in Fig. 9, is employed, which is a variation on the system 612.
  • the system 712 includes a single source 15 and lacks a WGA transfer line to the mixer.
  • the system 712 is advantageous as only a single source need be used.
  • the system 812 as shown in Fig. 10 includes a single injection ring 945 on the main discharge apparatus 630.
  • the injection ring 945 is operatively associated with at least one tee 63 set-up in a manner analogous to that for injection ring 45 shown in Fig. 3.
  • the densified layer discharge apparatus eliminates the ring 845, and injects both foam and WGA at the gate 1045 using a tee 63 set-up in a manner analogous to that for injection ring 45 shown in Fig. 3.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Producing Shaped Articles From Materials (AREA)

Abstract

L’invention concerne des procédés et des systèmes permettant d’introduire un accélérateur de gypse humide, ou tout autre additif produisant une viscosité élevée, dans une dispersion aqueuse de gypse calciné se trouvant dans un appareil de décharge en aval d’un mélangeur de stucco dans lequel la dispersion a été préparée. Ces procédés et systèmes se révèlent utiles lors de la production de produits de gypse variés tels qu’un panneau comprenant un panneau mural et les carreaux de plafond.
PCT/US2005/014504 2005-04-27 2005-04-27 Procedes et systemes permettant d’ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d’un melange WO2006115497A1 (fr)

Priority Applications (11)

Application Number Priority Date Filing Date Title
CNA2005800496010A CN101184703A (zh) 2005-04-27 2005-04-27 将高粘度石膏添加剂添加于煅烧石膏的混合后水性分散液中的方法和系统
MX2007012681A MX2007012681A (es) 2005-04-27 2005-04-27 Metodos y sistemas para agregar un aditivo de yeso de alta viscosidad a una dispersion acuosa de yeso calcinado post-mezclador.
AU2005331094A AU2005331094A1 (en) 2005-04-27 2005-04-27 Methods of and systems for adding a high viscosity gypsum additive to a post-mixer aqueous dispersion of calcined gypsum
NZ561843A NZ561843A (en) 2005-04-27 2005-04-27 Adding a production additive to an aqueous dispersion of calcined gypsum with the ratio of viscosity between the two is between 10:1 to 2:1
JP2008508810A JP2008539103A (ja) 2005-04-27 2005-04-27 高粘度の石膏添加材を焼石膏のポストミキサー水系分散剤に添加する方法及びシステム
PCT/US2005/014504 WO2006115497A1 (fr) 2005-04-27 2005-04-27 Procedes et systemes permettant d’ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d’un melange
EP05739963A EP1874705A1 (fr) 2005-04-27 2005-04-27 Procedes et systemes permettant d ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d un melange
CA002602053A CA2602053A1 (fr) 2005-04-27 2005-04-27 Procedes et systemes permettant d'ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d'un melange
BRPI0520228-0A BRPI0520228A2 (pt) 2005-04-27 2005-04-27 mÉtodos e sistemas para acrescentar um aditivo de gesso de alta viscosidade a uma dispersço aquosa pàs-misturador de gesso calcinado
IL186156A IL186156A0 (en) 2005-04-27 2007-09-20 Methods of and systems for adding a high viscosity gypsum additive to a post mixer aqueous dispersion of calcined gypsum
NO20075073A NO20075073L (no) 2005-04-27 2007-10-09 Fremgangsmater og systemer for a tilsette et gipsadditiv med hoy viskositet til en vandig dispersjon av kalsinert gips i en etter-blander

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2005/014504 WO2006115497A1 (fr) 2005-04-27 2005-04-27 Procedes et systemes permettant d’ajouter un additif de gypse a viscosite elevee a une dispersion aqueuse de gypse calcine obtenue a la suite d’un melange

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EP (1) EP1874705A1 (fr)
JP (1) JP2008539103A (fr)
CN (1) CN101184703A (fr)
AU (1) AU2005331094A1 (fr)
BR (1) BRPI0520228A2 (fr)
CA (1) CA2602053A1 (fr)
IL (1) IL186156A0 (fr)
MX (1) MX2007012681A (fr)
NO (1) NO20075073L (fr)
NZ (1) NZ561843A (fr)
WO (1) WO2006115497A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10618197B2 (en) 2016-02-10 2020-04-14 Yoshino Gypsum Co., Ltd. Gypsum-based board material producing apparatus
US10737979B2 (en) 2017-04-20 2020-08-11 United States Gypsum Company Gypsum set accelerator and method of preparing same
WO2020249499A1 (fr) 2019-06-14 2020-12-17 Basf Se Particules de gypse stabilisées

Families Citing this family (2)

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US10189180B2 (en) * 2014-01-15 2019-01-29 United States Gypsum Company Foam injection system with variable port inserts for slurry mixing and dispensing apparatus
US10737981B2 (en) * 2016-10-12 2020-08-11 United States Gypsum Company Method for making a lightweight gypsum composition with internally generated foam and products made from same

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US6409825B1 (en) * 2000-11-22 2002-06-25 United States Gypsum Company Wet gypsum accelerator and methods, composition, and product relating thereto
US6632550B1 (en) * 1997-08-21 2003-10-14 United States Gypsum Company Gypsum-containing product having increased resistance to permanent deformation and method and composition for producing it

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JP3494702B2 (ja) * 1994-07-15 2004-02-09 吉野石膏株式会社 混合撹拌機及び混合撹拌方法
JP3483062B2 (ja) * 1995-04-06 2004-01-06 株式会社竹中工務店 高流動コンクリート用細骨材
ID21641A (id) * 1997-08-21 1999-07-08 United States Gypsum Co Produk yang mengandung gypsum dengan peningkatan ketahanan terhadap deformasi tetap dan metode serta komposisi untuk memproduksinya
CN100354227C (zh) * 1998-07-30 2007-12-12 美国石膏公司 提高抗永久性变形的石膏制品和制备该制品的方法和组合物
US6409824B1 (en) * 2000-04-25 2002-06-25 United States Gypsum Company Gypsum compositions with enhanced resistance to permanent deformation
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US6632550B1 (en) * 1997-08-21 2003-10-14 United States Gypsum Company Gypsum-containing product having increased resistance to permanent deformation and method and composition for producing it
US6409825B1 (en) * 2000-11-22 2002-06-25 United States Gypsum Company Wet gypsum accelerator and methods, composition, and product relating thereto

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10618197B2 (en) 2016-02-10 2020-04-14 Yoshino Gypsum Co., Ltd. Gypsum-based board material producing apparatus
RU2742894C2 (ru) * 2016-02-10 2021-02-11 Йосино Джипсум Ко., Лтд. Устройство для изготовления листового материала на основе гипса
US10737979B2 (en) 2017-04-20 2020-08-11 United States Gypsum Company Gypsum set accelerator and method of preparing same
WO2020249499A1 (fr) 2019-06-14 2020-12-17 Basf Se Particules de gypse stabilisées

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EP1874705A1 (fr) 2008-01-09
JP2008539103A (ja) 2008-11-13
CA2602053A1 (fr) 2006-11-02
MX2007012681A (es) 2008-01-14
IL186156A0 (en) 2008-01-20
CN101184703A (zh) 2008-05-21
NO20075073L (no) 2007-11-26
AU2005331094A1 (en) 2006-11-02
NZ561843A (en) 2011-02-25
BRPI0520228A2 (pt) 2009-04-22

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