WO2008043085A1 - Procédé d'addition de trimétaphosphate de sodium dans une boue de gypse - Google Patents

Procédé d'addition de trimétaphosphate de sodium dans une boue de gypse Download PDF

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Publication number
WO2008043085A1
WO2008043085A1 PCT/US2007/080623 US2007080623W WO2008043085A1 WO 2008043085 A1 WO2008043085 A1 WO 2008043085A1 US 2007080623 W US2007080623 W US 2007080623W WO 2008043085 A1 WO2008043085 A1 WO 2008043085A1
Authority
WO
WIPO (PCT)
Prior art keywords
waterline
mixer
stmp
sodium trimetaphosphate
gypsum slurry
Prior art date
Application number
PCT/US2007/080623
Other languages
English (en)
Inventor
Gopalakrishnan Sethuraman
Charles Dennis Price
John L. Phillips
Original Assignee
National Gypsum Properties, Llc
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 claimed from US11/773,361 external-priority patent/US8066421B2/en
Application filed by National Gypsum Properties, Llc filed Critical National Gypsum Properties, Llc
Priority to CA 2667438 priority Critical patent/CA2667438A1/fr
Priority to MX2009003754A priority patent/MX2009003754A/es
Publication of WO2008043085A1 publication Critical patent/WO2008043085A1/fr

Links

Classifications

    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/53—Mixing liquids with solids using driven stirrers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/54—Mixing liquids with solids wetting solids
    • 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
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

  • gypsum products such as wallboard
  • Manufacturers mine and transport gypsum to a mill in order to dry it, crush/grind it and calcine it to yield stucco.
  • the reaction for the calcinations process is characterized by the following equation:
  • This equation shows that calcium sulfate dihydrate plus heat yields calcium sulfate hemihydrate (stucco) plus water vapor.
  • This process is conducted in a calciner, of which there are several types known in the art.
  • the stucco can contain one of two forms of calcium sulfate hemihydrate: the ⁇ -hemihydrate form and the ⁇ -hemihydrate form. These two types of stucco are often produced by different means of calcination. While the ⁇ -hemihydrate form is normally used due to its lower cost, either type of calcium sulfate hemihydrate is suitable for use.
  • Calcined gypsum (stucco) has the valuable property of being chemically reactive with water, and will "set” rather quickly when the two are mixed together.
  • This setting reaction reverses the above-described stucco chemical reaction performed during the calcination step. The reaction proceeds according to the following equation:
  • the calcium sulfate hemihydrate is rehydrated to its dihydrate state over a fairly short period of time.
  • the actual time required for this setting reaction generally depends upon the type of calciner employed and the type of gypsum rock that is used.
  • the reaction time can be controlled to a certain extent by the use of additives such as accelerators and retarders.
  • the reduction of water negatively impacts the quality of the board produced (i.e., the strength paper-to-core bond and the compressive strength of the board may be decreased), because the reduction of water usually results in some of the calcium sulfate hemihydrate not being rehydrated to its dihydrate state.
  • Wallboard gets its strength from the formation of crystals of calcium sulfate dihydrate during this rehydration process.
  • the adverse effect on wallboard quality from reduced water levels prevents manufacturers from further cutting manufacturing costs by reducing the amount of water used in the slurry composition.
  • lightweight wallboard is often produced by incorporating excess foam into calcined gypsum slurries, which in turn yield corresponding permanent voids in the product when the set gypsum is formed.
  • foaming agents have to be employed to produce the desired concentration of voids in the set gypsum, in order to obtain a product of desired density because the aqueous foams employed are inherently unstable.
  • the instability of the foaming agents leads to many of the bubbles coalescing and escaping the slurry before the set gypsum forms and thus, a significant amount of foaming agent must be used to get the desired lower density.
  • the significant amounts of foaming agents used further increases material costs in the production of wallboard.
  • other materials must be used to increase the strength of lightweight wallboard, such as natural polymers (e.g., starch) which further increases the cost of manufacturing gypsum wallboard.
  • STMP sodium trimetaphosphate
  • STMP is a combination of earth metals and is known by the chemical equation (NaPO 3 ) 3 . In its solid form it is a salt, but when dissolved in an aqueous solution, it is present as a trimetaphosphate ion. It is believed that the addition of STMP to the slurry promotes long crystal growth. Such crystals add the most strength to the core of the wallboard and also serve to form stronger bonds between the core and paper. While in theory, STMP can be used by manufacturers to decrease costs by increasing the core quality of wallboard, it has been discovered in practice that the current methods of adding STMP leads to further problems and delays.
  • a slurry is formed by premixing dry and wet ingredients in a mixing apparatus, such as a pin mixer.
  • the dry ingredients can include, but are not limited to, any combination of calcium sulfate hemihydrate (stucco), fiberglass, accelerator, and in some cases natural polymer (i.e., starch).
  • the wet ingredients can be made of many components, including but not limited to, a mixture of water, paper pulp, potash, and in some cases natural polymer (hereinafter, collectively referred to as a "pulp solution").
  • the pulp solution provides a significant portion of the water that forms the gypsum slurry of the core composition of the wallboard.
  • the dry ingredients and the pulp solution contain the basic chemical components of a piece of wallboard and conventional methods of preparing such wallboards are well known to those skilled in the art.
  • the dry ingredients and pulp solution can be mixed together in a pin mixer. In this manner, the dry ingredients and pulp solution create a fluid mixture or "slurry.”
  • the slurry is discharged from the mixer through the mixer's outlet chute or "boot” which spreads the slurry on a moving, continuous bottom sheet of paper.
  • a moving, continuous top sheet of paper is placed on the slurry and the bottom paper sheet, so that the slurry is positioned in between the top and bottom sheets of paper to form the board.
  • the board can then pass through a forming station which forms the wallboard to the desired thickness and width.
  • the board then travels along a belt line for several minutes, during which time the rehydration reaction occurs and the board stiffens.
  • the boards are then cut into a desired length and then fed into a large, continuous kiln for drying. During drying, the excess water (free water) is evaporated from the gypsum core while the chemically bound water is retained in the newly formed gypsum crystals.
  • the method for adding STMP to the gypsum slurry involves using a mixer with a hopper connected to and leading into the mixer, a pulp waterline connected to and leading into the mixer and at least one other waterline connected to and leading into the mixer. Dry ingredients, such as calcium sulfate hemihydrate (stucco), fiberglass, accelerator, and in some cases natural polymer (i.e., starch), are then added to the mixer through the hopper and a pulp water solution is added to the mixer through the pulp waterline. The mixer is operated to mix the dry ingredients with the pulp water solution to form a gypsum slurry. While any suitable mixer can be used to create the gypsum slurry, it is currently preferred to use a pin mixer.
  • a mixer with a hopper connected to and leading into the mixer, a pulp waterline connected to and leading into the mixer and at least one other waterline connected to and leading into the mixer.
  • Dry ingredients such as calcium sulfate hemihydrate (stucco), fiberglass
  • STMP can then be added to the gypsum slurry in the mixer through the other waterline.
  • This other waterline can be a gauging waterline or a foam waterline or both. While the STMP can be added through both the gauging waterline and the foam waterline (if both are present), it is preferred that the STMP only be added through one of the foam or gauging waterline.
  • a method for manufacturing gypsum wallboard includes pre- mixing dry ingredients and a pulp solution, in a mixing apparatus, such as a pin mixer to create the gypsum slurry.
  • the dry ingredients can include, but are not limited to, any combination of calcium sulfate hemihydrate (stucco), fiberglass, accelerator, and/or natural polymer (i.e., starch).
  • the wet ingredients of the pulp solution can include many components, including but not limited to, a mixture of water, paper pulp, potash, and in some cases natural polymer (i.e., starch).
  • other ingredients can be added to the pin mixer to form the slurry, including but not limited to, foam, accelerators, and/or retarders.
  • FIG. 1 shows a front perspective view of an exemplary pin mixer 10 that can be used to mix the dry ingredients with the pulp solution to produce the stucco slurry.
  • pin mixer 10 has a shell 12 that houses a plurality of pins (not shown).
  • a motor 18 operates to turn a rotor 16 which in turn spins the pins in shell 12 to mix the ingredients.
  • Pin mixer 10 also has hopper 30 that allows for the dry ingredients to be deposited into pin mixer 10.
  • Pulp waterline 20 for adding the pulp solution, gauging waterline 22 for adding additional water, and foam waterline 24 for adding foam are all connected to mixer 10 and allow for the pulp solution, water, and a foam solution to be added to the pin mixer and the gypsum slurry, respectively.
  • Each of the waterlines 20, 22, and 24 have an inlet 26 that allow for other components to be added to the waterlines.
  • the slurry is deposited on a bottom stream of cover paper (not shown) through slurry discharge 32, which can be a boot or other suitable conduit. While Figure 1 show an exemplary pin mixer used in a gypsum product manufacturing process, it will be appreciated that any number of suitable mixers exist for forming the slurry and that Figure 1 is only provided for the sake of discussion.
  • One exemplary embodiment of a method that increases the effectiveness and efficiency of introducing STMP into a gypsum slurry involves the step of introducing an amount of either dry STMP or a diluted solution of STMP into the gauging waterline.
  • the gauging waterline allows for water to be added to the pin mixer.
  • STMP can be added to the water passing through the gauging waterline through an inlet 26 of gauging waterline 24, so that STMP will be added to the slurry as water is added to the slurry through gauging waterline 24.
  • any number of means of adding the STMP to the gauging waterline can be used, it normally involves the use of a pump to deliver a diluted solution of STMP directly to the gauging waterline 24 through an inlet.
  • Another embodiment of a method that increases the effectiveness and efficiency of introducing STMP into a gypsum slurry involves the step of introducing an amount of either dry STMP or a diluted solution of STMP into the foam waterline.
  • the core density and the overall weight/density of the wallboard can be controlled and reduced by incorporating foam into the stucco slurry.
  • the foam usually is prepared using foam water, a foaming agent (i.e., soap), and air in any number of mechanical foam generation devices.
  • foam is added to pin mixer 10 through foam waterline 22 and STMP can be added to the foam through inlet 26 of foam waterline 22, so that STMP will be added to the gypsum slurry as the foam is added to the gypsum slurry.
  • any number of means of adding the STMP to the foam waterline 22 can be used, it normally involves the use of a pump to deliver a diluted solution of STMP directly to the foam waterline 22 through inlet 26.
  • the above-described methods involve the step of adding a STMP in a dry form or a diluted solution of STMP to the gauging waterline or foam waterline.
  • the solubility of commercially available STMP in solution typically ranges from about 13% to about 21%. It is preferred that the diluted solutions in these exemplary methods be a solution with about 8% to 18% STMP dissolved therein.
  • the concentration of the diluted solution of STMP will be dependent on the mechanism for adding the STMP to the gauging waterline or foam waterline.
  • the concentration of the diluted solution of the STMP will be dependent on the pump's throughput.
  • the pump may only allow for STMP to be added in diluted solutions with about 8% to 10% STMP dissolved therein.
  • the addition of the STMP into the foam waterline or gauging waterline leads to greater efficiency and effectiveness of adding STMP to a gypsum product manufacturing process. For example, it reduces the amount of STMP needed to produce gypsum wallboard. Only about .1 to about .65 pounds of STMP per 1,000 square feet of gypsum slurry needs to be used to have beneficial effects on the quality of the board.
  • the addition of STMP in this manner also has the benefit of reducing the amount of natural polymer used to create gypsum wallboard.
  • Natural polymers such as starch, are added to the slurry in order to increase the strength of the paper to core bond and to increase the strength of the board. Such natural polymers are an expensive component and the reduction of the amount of natural polymer needed can substantially reduce the cost involved in manufacturing gypsum wallboard.
  • the addition of STMP to the gauging waterline or the foam waterline increases the efficiency and effectiveness of adding STMP to the gypsum slurry which allows for an increase in quality of the produced wallboard. This increase in quality allows for manufacturers to reduce the amount of natural polymers added to the slurry without detrimentally effecting the overall quality of the wallboard. This reduction in natural polymers also reduces the cost of producing wallboard.
  • Table I shows an exemplary component formulation in pounds per 1,000 square fee for Vi inch thick wallboard. It is understood by one skilled in the art that enough of each component is added to produce dry boards with weights around 1400 and 1650 pounds per 1,000 square feet for a 1 A inch thick wallboard ("msf '). It will be appreciated by one skilled in the art that while these examples are for a 1 A inch thick board, the exemplary methods can be used to produce wallboard of any thickness. TABLE I - Slurry Formulation
  • the slurry composition contains an accelerator, such as BMA (produced by National Gypsum Company), a retarder, such as, Proteinaceious Retarder (produced by the National Gypsum Company), Accumer (produced by Rohm & Haas), and RA-77 (produced by Rhodia), and a dispersant, such as Diloflow (produced by Geo Chemicals), Gypflow (produced by Ande) and Daxad (produced by Dow/Hampshire).
  • BMA produced by National Gypsum Company
  • a retarder such as, Proteinaceious Retarder (produced by the National Gypsum Company), Accumer (produced by Rohm & Haas), and RA-77 (produced by Rhodia)
  • a dispersant such as Diloflow (produced by Geo Chemicals), Gypflow (produced by Ande) and Daxad (produced by Dow/Hampshire).
  • Table II a series of samples were prepared using the above formulation with varying amounts of STMP added to the manufacturing process through the gauging waterline.
  • Table III a series of samples were prepared using the above slurry formulation with reduced amounts of starch.
  • the samples also have varying amount of STMP added to the manufacturing process through the gauging waterline.
  • the samples were tested for humidified defection and a few of the samples were also tested for width shrinkage. The tests revealed that starch could be reduced with negligible effects on the board strength.
  • Each line of Table III represents an average of five samples tested. The last line is the control sample where no STMP was used and no reduction in starch occurred.
  • the described exemplary embodiments deal with methods for adding STMP to a gypsum slurry used to produce gypsum wallboard, but it will be appreciated by one skilled in the art that the described methods could also be used to add STMP to any type of gypsum slurry. It is anticipated that a variety of other modifications and changes will be apparent to those having ordinary skill in the art and that such modifications and changes are intended to be encompassed within the spirit and scope of the invention as defined by the following claims.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

La présente invention concerne un procédé d'addition efficace de trimétaphosphate de sodium dans une boue de gypse. Dans un mode de réalisation à titre d'exemple, le trimétaphosphate de sodium est ajouté pendant l'addition d'une mousse dans la boue de gypse à travers la conduite de la mousse. Dans un autre mode de réalisation à titre d'exemple, le trimétaphosphate de sodium est ajouté pendant l'addition d'eau additionnelle dans la boue de gypse à travers la conduite de mesure du débit. Le trimétaphosphate de sodium peut être ajouté à travers une conduite ou les deux sous sa forme sèche ou dans une solution diluée.
PCT/US2007/080623 2006-10-05 2007-10-05 Procédé d'addition de trimétaphosphate de sodium dans une boue de gypse WO2008043085A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CA 2667438 CA2667438A1 (fr) 2006-10-05 2007-10-05 Procede d'addition de trimetaphosphate de sodium dans une boue de gypse
MX2009003754A MX2009003754A (es) 2006-10-05 2007-10-05 Metodo de añadir trimetafosfato de sodio a una suspension espesa de yeso.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US82829106P 2006-10-05 2006-10-05
US60/828,291 2006-10-05
US11/773,361 2007-07-03
US11/773,361 US8066421B2 (en) 2007-07-03 2007-07-03 Method of adding STMP to a gypsum slurry

Publications (1)

Publication Number Publication Date
WO2008043085A1 true WO2008043085A1 (fr) 2008-04-10

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Application Number Title Priority Date Filing Date
PCT/US2007/080623 WO2008043085A1 (fr) 2006-10-05 2007-10-05 Procédé d'addition de trimétaphosphate de sodium dans une boue de gypse

Country Status (3)

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CA (1) CA2667438A1 (fr)
MX (1) MX2009003754A (fr)
WO (1) WO2008043085A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130239848A1 (en) * 2010-11-23 2013-09-19 Saint-Gobain Placo Sas Calcium Sulphate-Based Products and Methods for the Manufacture Thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5135805A (en) * 1990-07-27 1992-08-04 Georgia-Pacific Corporation Method of manufacturing a water-resistant gypsum composition
US20010001218A1 (en) * 2000-04-12 2001-05-17 Luongo Joseph S. Strengthened, light weight construction board and method and apparatus for making the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5135805A (en) * 1990-07-27 1992-08-04 Georgia-Pacific Corporation Method of manufacturing a water-resistant gypsum composition
US20010001218A1 (en) * 2000-04-12 2001-05-17 Luongo Joseph S. Strengthened, light weight construction board and method and apparatus for making the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130239848A1 (en) * 2010-11-23 2013-09-19 Saint-Gobain Placo Sas Calcium Sulphate-Based Products and Methods for the Manufacture Thereof
US9382153B2 (en) * 2010-11-23 2016-07-05 Saint Gobain Placo Sas Calcium sulphate-based products and methods for the manufacture thereof

Also Published As

Publication number Publication date
MX2009003754A (es) 2009-06-16
CA2667438A1 (fr) 2008-04-10

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