Struvite-K and Syngenite Composition for Use in Building Materials

Abstract

A composition and process for the manufacture thereof for use in a hybrid building material comprising at least in part Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O) and Struvite-K (KMgPO.sub.4.6H.sub.2O). Specified constituents, including magnesium oxide (MgO), monopotassium phosphate (MKP) and stucco (calcium sulfate hemihydrate) are mixed in predetermined ratios and the reaction proceeds through multiple phases reactions which at times are proceeding simultaneously and in parallel and reaction may even compete with each other for reagents if the Struvite-K reaction is not buffered to slow down the reaction rate). A number of variable factors, such as water temperature, pH mixing times and rates, have been found to affect resultant reaction products. Preferred ratios of chemical constituents and manufacturing parameters, including predetermined and specified ratios of Struvite-K and Syngenite may be provided for specified purposes, optimized in respect of stoichiometry to reduce the combined heat of formation to non-destructive levels.

Claims

1-12. (canceled)

13. A building composition for use in a building product comprising Struvite-K (KMgPO.sub.4.6H.sub.2O), Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O) and stucco hemihydrate and Magnesium Oxide (MgO) used for producing a building material having increased strength and integrity.

14. The building composition for use in a building product according to claim 13, wherein the resultant reaction products are in the following ranges: KMgPO.sub.4.6H.sub.2O: of from 0.1 to 67.0 weight percent; K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O: of from 2.5 to 60.0 weight percent; and stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

15. The building composition for use in a building product according to claim 14, wherein the resultant reaction products are in the following ranges: KMgPO.sub.4.6H.sub.2O: of from 15.1 to 37.0 weight percent; and K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O: of from 12.5 to 46.0 weight percent; and unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

16. A fire-resistant hybrid wallboard comprising at least in part a composition containing Struvite-K (KMgPO.sub.4.6H.sub.2O), Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O), stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) used for producing a building material having structural integrity.

17. The fire-resistant hybrid wallboard according to claim 16, further comprising a facing material including a randomly aligned inorganic fibrous mat with a coating in part comprising a composition containing Struvite-K (KMgPO.sub.4.6H.sub.2O) and Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O).

18. The fire-resistant hybrid wallboard according to claim 16, wherein the composition includes the constituent compounds in the following ranges: KMgPO.sub.4.6H.sub.2O: of from 0.1 to 67.0 weight percent; K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O: of from 2.5 to 60.0 weight percent; and amorphous materials at least in part comprising unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

19. The fire-resistant hybrid wallboard according to claim 18, further comprising a facing material including a randomly aligned inorganic fibrous mat with a coating in part comprising a composition containing Struvite-K (KMgPO.sub.4.6H.sub.2O), Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O), unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO).

20. The fire-resistant hybrid wallboard according to claim 16, wherein the composition includes the constituent compounds in the following ranges: KMgPO.sub.4.6H.sub.2O: of from 15.1 to 37.0 weight percent; and K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O: of from 12.5 to 46.0 weight percent; and unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

21. The fire-resistant hybrid wallboard according to claim 18 wherein the stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) are left over reactants randomly distributed in a matrix within the crystalline structures that are presented by the reacted Struvite-K and Syngenite.

22. The fire-resistant hybrid wallboard according to claim 20 further comprising a facing material including a randomly aligned inorganic fibrous mat with a coating in part comprising a composition containing Struvite-K (KMgPO.sub.4.6H.sub.2O) and Syngenite (K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O).

23. A fibrous mat comprising randomly aligned inorganic fiber strands for use as a facing material in a wallboard, wherein the fibrous mat is precoated with an ultrahigh fire resistant, weather proof, high-strength, and abrasion resistant hybrid ceramic coating comprising stoichiometrically balanced Struvite-K and Syngenite product materials, the facing material providing for enhanced water resistance of the wallboard.

24. The fibrous mat according to claim 23 wherein the abrasion resistant hybrid ceramic coating further comprises unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO).

25. The fibrous mat according to claim 23 wherein the stoichiometrically balanced Struvite-K and Syngenite product materials further comprise KMgPO.sub.4.6H.sub.2O(Struvite-K): of from 0.1 to 67.0 weight percent; and K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O(Syngenite): of from 2.5 to 60.0 weight percent; and unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

26. The fibrous mat according to claim 25 wherein the stoichiometrically balanced Struvite-K and Syngenite product materials further comprise KMgPO.sub.4.6H.sub.2O(Struvite-K): of from 15.1 to 37.0 weight percent; and K.sub.2Ca(SO.sub.4).sub.2.H.sub.2O(Syngenite): of from 12.5 to 46.0 weight percent; and unreacted stucco hemihydrate (CaSO.sub.4.1/2H.sub.2O) and Magnesium Oxide (MgO) making up the remaining product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will now be discussed in further detail below with reference to the accompanying figures in which:

[0031] FIG. 1 is photomicrograph of a void in the resulting material developed in one of the tested formulations to determine the local structure of the resultant reaction products;

[0032] FIG. 2 is a ternary graph showing the proportions of MgO:MKP:stucco for specified trial runs and plots the various formulations used in the testing regime; and

[0033] FIG. 3 is a schematic plan view showing in cross-section a plug flow mixer reactor such as may be utilized in the production of the inventive compositions of matter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The precise quantitative equations are being refined with reliance on the experimental data compiled to date. Certain qualitative trends can be seen from preliminary lab results and scientific deductive reasoning using known scientific principles. The above listed 5 process conditions may be used to predict the necessary starting conditions based on the yields of Struvite-K and Syngenite desired in the final mixture. The possible modifications of the initial parameters will now be described in greater detail to show the effect of how varying any one particular parameter will change the ultimate resulting composition derived from the starting constituents.

[0035] To be avoided in the reaction is the overwhelming heat that the Magnesium Phosphate reaction generates (exothermically) which tends to destabilize/overwhelm the gypsum rehydration reaction and generate amorphous gypsum hemihydrate as an unwanted by-product. Thus, to provide an appropriate buffer is considered essential. Boric acid is ideal to retard the Magnesium Phosphate reaction, while it also serves as a mechanism to protect gypsum recrystallization against the adverse effects of thermal shock when the Magnesium Phosphate begins to form.

[0036] Using sulphuric acid (H.sub.2SO.sub.4) to pretreat the water and further accelerate the Struvite-K reaction may be helpful. To reduce costs of materials, as much as 70% stucco of the overall formulation can be used as a replacement beneficial co-reactant instead of Magnesium Oxide and monopotassium phosphate (MKP), since the gypsum is significantly cheaper and lighter weight than these materials.

[0037] As a by-product and a point of unexpected discovery, Syngenite is also generated, which is material that is more fire resistant than gypsum. However, Syngenite is not as strong and fire resistant as the combination of Struvite-K and Syngenite. Syngenite also provides an incidental benefit as a compositing factor between the Magnesium Phosphate and the gypsum hemihydrate, whereby it incorporates plasto-elastomeric characteristics, thereby rendering the final product significantly less brittle as well as more flexible, increasing manipulability, and making the board easier to score/cut. This is also a significant improvement over known Magnesium Oxychloride boards, for example, such as those described in U.S. Pat. Pub. 2013/0115835 and Portland cement based cement building panels.

[0038] Additionally, and ideally, silicone is added to the mix to achieve four other complimentary characteristics, [0039] 1) forming a catalyzed silicone in the presence of the Magnesium Phosphate and acids [0040] 2) providing a mechanism for thermal resistance to the gypsum and permits recrystallization of the Magnesium Phosphate [0041] 3) serving to retard the Magnesium Phosphate reaction, and [0042] 4) providing a defoaming material to break down any foam that may be generated as a byproduct of the reaction of the Sulfuric Acid with CaCO.sub.3, which is a known impurity in natural gypsum. Increasing the amount of silicone addition further imparts substantial water resistance to the board, and in increase in catalyzed silicone even more so. Total water resistance has been increased using significantly a lesser amount of silicone than is typically used/required to meet ASTM performance requirements for wet area building panels. Testing has shown that a maximum absorption rate of 2% may be achieved, while typically results on conventional water resistant gypsum wallboard, glass-reinforced gypsum boards, produce on average absorption that is at best 3.5% to 4% total water resistance.

[0043] However, the materials generated as a result of the present invention are by their nature water resistant and do not breakdown in the presence of water as would for example, Magnesium Oxychloride boards or traditional gypsum boards, which require the incorporation of water resistant additives, such as wax or silicone. Incorporation of a Polysiloxane in the present formulations restrains water wicking into the open areas and through the matrix of the products made in accordance with the present invention, essentially making it water impervious to an extent that water is no longer able to wick into the material. Moreover, even when bulk water or vapor water either wicks into or is transferred into the material/materials generated according to the present invention, it has no detrimental effect thereon and the material maintains its original strength. So as to prevent the intrusion of bulk or vapor water into and throughout the inventive compositions, a Polysiloxane is added only if complete water imperviousness is a requirement, for example, such as in regions and localities where building codes have driven the specification.

[0044] One method of using Struvite-K in building materials has been suggested for use in roads in replacement of Portland Cement. See for example: Optimisation of the preparation of a phosphomagnesium cement based on struvite and K-struvite H. Hammi and A. Mnif, Laboratoire de Valorisation des Materiaux Utiles, Centre National de Recherches en Sciences des Matriaux, Technopole Borj Cedria, Soliman, Tunisie, MATEC Web of Conferences Vol. 3, page 01071 (2013). Such compounds are also useful in the production of other building materials, such as wallboard panels, ceiling tiles, etc. Such uses require the efficient, timely and inexpensive production such that they can be incorporated into the structural members in which they are being used.

[0045] It has been noted that the production of such compounds and their ability to set in a timely fashion is dependent on the stoichiometry of the various precursors to the final set product, which is essentially in the form of KMg(PO.sub.4).6(H.sub.2O). That is, it has been found as a surprising and unexpected result that the ratios of ingredients as follows will provide the best results in the desired characteristics:

[0046] The following data is used to drive the rapidity and direction of the reactions: [0047] 1. Thermodynamic principles: [0048] a. Gibb's free energy of formationthe Gibb's free energy of reaction will become more negative and, in part, more spontaneous as higher Struvite-K yields are produced, as it is shown with the faster reaction time when producing the samples. [0049] b. Enthalpy of formationthe enthalpy of formation will become more negative as higher yields of Struvite-K are produced, as shown by the larger temperature increase in such samples at constant masses. [0050] c. Entropy of formationthe entropy of formation will become more negative as higher yields of Struvite-K are produced, due to decreasing entropy during crystallization. [0051] 2. Rheology of the reaction mixture: [0052] a. Density of the mixturethe density of the fluid before crystallization will increase as higher Struvite-K yields are produced, due to the increase bulk density of the mixture before setting. [0053] b. Viscosity of the mixturefor the same reasons listed above, the viscosity will increase as higher Struvite-K yields are produced. [0054] 3. Reactant masses and stoichiometric considerations: [0055] a. Monopotassium phosphate (KH.sub.2PO.sub.4)the monopotassium phosphate requirement will increase as higher Struvite-K yields are produced until the mass ratio of monopotassium phosphate (KH.sub.2PO.sub.4) to magnesium oxide (MgO) reaches 3.37:1, from stoichiometric considerations. [0056] b. Magnesium oxide (MgO)the magnesium oxide requirement will increase with higher Struvite-K yields until the mass ratio of monopotassium phosphate to magnesium oxide reaches 3.37:1, from stoichiometric considerations. [0057] c. Stucco (gypsum hemihydrate)the stucco requirement will not be affected by higher Struvite-K yields, as it is not considered in this reaction. [0058] d. Waterthe water requirement will increase as higher Struvite-K yields are produced until the mass ratio of monopotassium phosphate (KH.sub.2PO.sub.4) to water (H.sub.2O) equals 2.96:1, from stoichiometric considerations. Water temperature is also considered a factor. [0059] 4. pH Requirements: [0060] a. Based on experimental data as the pH is lowered with the help of any acid, the yield of Struvite-K increases, since the reaction happens faster and it uses the raw materials at an increased rate. [0061] 5. Process Reaction Conditions: [0062] a. The reaction, as theorized, is a thermodynamically driven reaction. Therefore, starting at a higher temperature will yield lower amounts of Struvite-K.

[0063] The chemical reaction providing the optimum results has been determined to be:

##STR00001##

the reaction occurring in the presence of small amounts of H.sub.2SO.sub.4, H.sub.3BO.sub.3, both acting as buffers for reducing the reaction rate, and one or more siloxanes to restrain water wicking and Naphthalene Sulfonate as a fluidizer.

[0064] The Struvite-K Reaction is an exothermic reaction and proceeds very rapidly:

MgO+KH.sub.2PO.sub.4+5H.sub.2O.fwdarw.KMg(PO.sub.4).6(H.sub.2O).

[0065] The basic reactions that are considered to occur are set forth above and the reaction process that is considered to occur is described below. It should also be understood that the precise reaction mechanism remains under study, and that certain reaction parameters, such as pH, water temperature, and timing of mixing and additions, have been explored as severely affecting the reaction rates, products and final structures. The information derived therefrom is expected to provide a base of information that will enable customization of the reaction products and extent of completion of the reaction, as desired for specific applications.

[0066] In the current invention, it has been found that the degree and length of mixing plays a significant role in both how the reaction proceeds and the ultimate yield of Syngenite and Struvite-K. Using the ratios as provided above, it has been found that minimal mixing yields higher ratios of Syngenite and longer mixing yields higher ratios of Struvite-K. Unexpectedly, it was discovered that a short mixing period enables a first, low temperature generating exothermic reaction and, when the mixing is stopped minimally after 30 seconds to one minute, complete set/hardening of the slurry can take up to 50 minutes. X-Ray Diffraction (XRD) tests have indicated that samples mixed this way yield higher amounts of Syngenite than Struvite-K, as well as elevated ratios of unreacted MgO (Periclase has been observed) and Bassanite (CaSO.sub.4.1/2H.sub.2O). Though each sample appeared to be set after this short mixing, in fact it was unexpectedly discovered that the sample had only formed a shell around an unsetstill fluid inner core, and that the sample was maintaining a temperature around 86 F. The shell was broken open and all materials were found to go back into solution immediately when mixed with the still fluid inner core material. Further mixing for an additional 30 to 40 seconds instigated a second reactionan exothermic reaction wherein the temperature climbed to a maximum of 212 F.initially indicative of a magnesium phosphate reaction, but in fact, following an XRD test on this sample material, was determined to comprise Struvite-K.

[0067] Subsequent prolonged multi and singular stage hand and high speed mixing of follow-up samples composed/formulated with an identical formulation as listed below, demonstrated dramatically elevated Struvite-K yield ratios.

[0068] XRD results demonstrate the benefit of prolonged mixing of the specific formulation and its ratios are set forth below:

TABLE-US-00001 TABLE 1 KMgPO.sub.46H.sub.2O K.sub.2Ca(SO.sub.4).sub.2H.sub.2O Unreacted MgO CaSO.sub.40.67H.sub.2O (Struvite-K) (Syngenite) (Periclase) (Bassanite) (PDF-00-035- (PDF-00-028- (PDF-00-045- (PDF-00-047- Samples 0812) 0739) 0946) 0964) A 67.1 25.0 6.6 1.2 B 66.4 25.8 7.1 0.7 C 66.0 26.4 6.9 0.6 D 66.0 26.4 6.9 0.6

[0069] As a result of this discovery it is a product of the invention herein disclosed that mixing as described above in combination with the specific formulation shown above and raw material addition variations detailed below are novel and unexpected to one normally skilled in the art from the previously known magnesium oxide or magnesium oxychloride type boards.

[0070] By varying the reaction stoichiometry above, the reactions can be tailored to produce desired or customized percentages of the different products. For example, the reaction can be customized to produce the maximum amount of Struvite-K, as above, or to produce a maximum of the Syngenite, or a suitable desired combination of the two.

[0071] Combining the formulation above with suitable changes to the following ranges imparts improved economic efficiencies relating to large scale Struvite-K yield as a result of the process/formulation.

[0072] In order to generate more Struvite-K the following method is used: [0073] a. Using a multi-stage mixing apparatus, such as a plug flow mixer as shown in FIG. 3, multilevel pen and or scraper mixer or combination of them, or using just a mixer that allows for a long dwell time with raw material supply and feed-through/output controls equivalent to a manufacturing speed for a typical 4 foot wide and to 1 thick board ranging from approximately a minimum of 20 feet/min to a maximum of 750 feet/min. The raw materials that are mixed and combined within the mixer are the following: (Dwell time must be equal to or greater than and min of 4 minutes and a max of 12 minutes). [0074] 17.2%=Magnesium Oxide (MgO): Lite dead burned, medium dead burned, hard dead burned MgO, or a combination of any two or three alternatives, are intended to optimize and reduce raw material cost meanwhile yielding both efficient and optimal performance features in the result composite generated slurry formulation. [0075] 34.5%=MKP (Mono-Potassium Phosphate or KDP Potassium Dihydrogen Phosphate KH.sub.2PO.sub.4) will improve the molar ratio of Magnesium Oxide (MgO) to potassium Dihydrogen phosphate and also impart a reduction in the rate of reaction via reduced rate of dissociation. The preferred MKP or KDP may be either of a food grade or agricultural grade. [0076] 17.2%=Beta Hemihydrate (processed gypsum stuccoCaSO.sub.4.1/2 H.sub.2O): as a co-reactant which generates an initial reaction that slows the overall reaction via an initial rehydration/uptake of associated wateran initial step which generates a first temperature rise reaction, an endothermic reaction with the potassium content (setting off a dissolution of the K from the MKP to join with the forming dihydrate to form Syngenite). The Hemihydrate may be of a minimum purity ranging from approximately 65% to a maximum purity of 100%. The higher purity hemihydrate improves the uptake of potassium as dihydrate is forming and thereby further slows the secondary KMgPO.sub.4.6H.sub.2O (Struvite-K) reaction and elevates the Struvite-K yield in the final reaction. Because the exothermic reaction that generates the KMgPO.sub.4.6H.sub.2O is so hot (up to 212 F. (100 C.)), the rehydrated dihydrate portion of the derived Syngenite calcines to a minor extent. The Potassium (K) that had been used up in the first Syngenite reaction is then released into solution in stages and is ultimately reused in the KMg.sub.2PO.sub.4.6H.sub.2O generation process. [0077] 31.1%=H.sub.2O (Water) [0078] Trace remaining additives all represent 1.5% of the overall mix in total combined addition. [0079] Sulfuric Acid (H.sub.2SO.sub.4): is added to the water to change the pH and improve the instigation of the overall acid based reaction. [0080] Boric Acid (H.sub.3BO.sub.3): Boric Acid is a significant additive specifically because it offers a benefit to both endothermic and exothermic reactions. In the first reaction it serves to protect the hemihydrate to water rehydration from the heat of the secondary MgO/MKP/H.sub.2O reaction, and allows the forming Syngenite to hold onto the K longer than if there were thermal shield being provided by the Boric Acid. In the case of the MgO/MKP/H.sub.2O reaction the Boric Acid is known retarder to Magnesium Phosphate Cement reactions. [0081] Siloxanes, such as Polysiloxane (C.sub.2H.sub.6OSi).sub.n, polydimethylsiloxane (CH.sub.3[Si(CH.sub.3).sub.2O].sub.nSi(CH.sub.3).sub.3), and others, in very low addition amounts may be used as a defoamer as the MgO/MKP and an impurity within the Hemihydrate source (CaCO.sub.3) reacts with the MgO in the presence of water to cause a foaming reaction that is not desirable. If no impurities are present, the Polysiloxane stays intact throughout the entire course of the first and second reactions. [0082] Naphthalene Sulfonate, such as C.sub.10H.sub.8NNaO.sub.3S, in very low additive amounts serves as a fluidizer or dispersant for the overall mix. [0083] b. Higher Purity Beta Hemihydrate: the higher the purity of the hemihydrate the overall reaction slows down/retards and a greater uptake of K in the initial reaction which in turn causes more generation of Struvite-K in the final reaction as long as the additives in their current disclosed addition ratios are approximately maintainedbutthere is a maximum yield limit that can be obtained. Decrease of either the MgO or the MKP addition will produce less Struvite-K. Increase in the MgO and or the MKP additive should generate equivalent or greater yield ratios of Struvite-K, but requires an increase in the Beta hemihydrate addition or an increase in the hemihydrate purity. In this case the Boric and Sulfuric Acid additions may also be increased.

[0084] The above described method changes the ratios somewhat so that combining the formulations that above with the following ranges will impart improved economic efficiencies relating to large scale Syngenite yield as a result of the process/formulation.

[0085] In order to generate more Syngenite, the following method is used: [0086] a. The use of a multi-stage mixing apparatus such as a plug flow mixer, multilevel pin and or scraper mixer or combination of both or just a mixer that allows for a long dwell time with raw material supply and feed-through/output controls equivalent to a manufacturing speed ranging from approximately a minimum of 20 feet/min to a maximum of 750 feet/min. This permits the raw materials being mixed and combined within said mixer to the following ratios and will provide dwell times equal to or greater than and min of 2 minute or a max of 12 minutes: [0087] 17.2%=Magnesium Oxide (MgO): Lite dead burned, medium dead burned, hard dead burned MgO, or a combination of any two or three alternatives intended to best optimize raw material cost while yielding both efficient and optimal performance features in the result composite generated slurry formulation. [0088] 34.5%=MKP (Mono-Potassium Phosphate or KDP Potassium Dihydrogen Phosphate KH.sub.2PO.sub.4) to improve the molar ratio of magnesium oxide to potassium Dihydrogen phosphate and as well, impart a reduction in the rate of reaction while via reduced rate of dissociation. [0089] 17.2%=Beta Hemihydrate (processed gypsum stuccoCaSO.sub.4.1/2H.sub.2O): as a co-reactant which generates an initial reaction that slows the overall reaction via an initial rehydration/uptake of associated wateran initial step which generates a first temperature rise reaction, an endothermic reaction with the potassium content (setting off a dissolution of the K from the MKP to join with the forming dihydrate to form Syngenite). The Hemihydrate may be of a minimum purity ranging from approximately 65% to a maximum purity of 100% wherein, said higher purity hemihydrate improves the uptake of potassium as dihydrate is forming and thereby further slows the secondary KMgPO.sub.4.6H.sub.2O (Struvite-K) reaction and elevates the Syngenite yield in the final reaction, if the exothermic reaction that generates the KMgPO.sub.4.6H.sub.2O is not hot enough or in a range no greater than 140 F. to 180 F. the rehydrating hemihydrate to dihydrate and then Syngenite (requiring the presence of the hemihydrate) does not calcine to any extent, and thus the available K to yield Struvite-K is reduced and results in a lower ratio of Struvite K to Syngenite. [0090] 31.1%=H.sub.2O (Water) [0091] The remaining additives all represent 1.5% of the overall mix in total combined addition. [0092] With the changes in the ratios between the MgO, MKP and the CaSO.sub.4.1/2H.sub.2O to achieve desired results in the final product, as described above, appropriate changes will be required in the stoichiometry of these three ingredients. [0093] Sulfuric Acid (H.sub.2SO.sub.4): is added to the water to change the pH and improve the instigation of the overall acid based reaction. [0094] Boric Acid (H.sub.3BO.sub.3): The Boric Acid is a desirable ingredient specifically because it offers a benefit to both endothermic and exothermic reactions. In the first reaction it serves to protect the hemihydrate to water rehydration from the heat of the secondary MgO/MKP/H.sub.2O reaction, and allows the Syngenite as it is forming to hold onto the K longer than if there were a shield being provided by the Boric Acid. In the case of the MgO/MKP/H.sub.2O reaction, the Boric Acid is known to retard the Magnesium Phosphate Cement reactions. The Boric acid contribution and benefit to both reactions was not an intended result, and thus was an unexpected discovery. [0095] Siloxanes, such as Polysiloxane (C.sub.2H.sub.6OSi).sub.n, polydimethylsiloxane (CH.sub.3[Si(CH.sub.3).sub.2O].sub.nSi(CH.sub.3).sub.3), and others, in very low addition amounts are used as a defoamer as the MgO and an impurity within the Hemihydrate source (CaCO.sub.3) reacts with the MgO in the presence of water to cause a foaming reaction that is not desired at present. If no impurity is present, the Polysiloxane stays intact throughout the entire course of the first endothermic and second exothermic reactions. [0096] Naphthalene Sulfonate, such as C.sub.10H.sub.8NNaO.sub.3S, in very low additive amounts serves as a fluidizer or dispersant for the overall mix. [0097] b. Higher Purity Beta Hemihydrate: the higher the purity of the hemihydrate the overall reaction slows down/retards and a greater uptake of K in the initial reaction which in turn causes more generation of Syngenite in the final reaction as long as the additives in their current disclosed addition ratios are approximately maintainedbutthere is a maximum yield that can be obtained. Maintaining a second exothermic reaction that does not exceed 180 F. (82.2 C.) is critical in generating a greater ratio of Syngenite to Struvite-K. If you decrease either the MgO or the MKP addition then you have less Struvite-K. In this case the Boric and Sulfuric Acid additions must also be increased. [0098] 2. To generate equivalencies of both Syngenite and Struvite-Kthe reactions must be balanced in a way to enable the second exothermic reaction to exist within the 180 F. to 212 F. (82.2-100 C.) range, but at a limited exothermic temperature and time of reaction so as to reduce the ratio of Struvite-K formation.

[0099] It has been found that the mixture as set forth above provides a significantly greater yield of the Struvite-K, up to 67%, than heretofore provided by known processes, and all with a minimum of additional necessary inputs.

[0100] In the end, the gypsum component makes the board panel more affordable and the final product is a dramatic improvement both from a physical and long-term performance standpoint over conventional gypsum panels. It is naturally UV resistant, that is, protects against penetration of ultraviolet rays, so it needs no performance surface coating and it is extremely water resistant. A similar product described by Surace in GB 2,445,660 (equivalent US Pat Pub. No. 2008/171,179) while being capable of being produced in a continuous and or batch process, clearly states that the use of hemihydrate gypsum stucco is to be avoided because of the requirement of significant energy input needed to dry the hemihydrate. In the above described, product because of the simultaneous production of Syngenite, a similarly stoichiometric reaction that requires no added external heat for drying, provides the necessary thermal energy for the reaction. This is a direct result of the reaction of the hemihydrate with the monopotassium phosphate (MKP).

[0101] In use, the boards having the specified compositions of Struvite-K in specified ratios to the Syngenite can be tailored for specific desired uses.

[0102] An initial attempt to provide a light weight gypsum board was included following steps to obtain a sample result:

[0103] The initial base material formulation was a 1:1:1 mixture, that is, comprising in equal proportions MgO:MKP-(KH.sub.2PO.sub.4):stucco (hemihydrate CaSO.sub.4.1/2H.sub.2O), with the MgO, MKP and hemihydrate gypsum being added in doses of 15 g each as dry powder to the mixer and dry premixed for 45 seconds to ensure homogeneity of the materials. Additional base materials additions were 0.03 g silicone oil, comprising polymethylhydrogensiloxane, and a dispersant comprising 0.05 g polynapthalene sulfonate.

[0104] To this base mixture following the dry mix for all samples below, 17 g water (H.sub.2O) was added. This base mixture was then used for several lab runs, by the additions as noted in the table below, to obtain several samples as listed in TABLE 2. The mixture, including the water, was mixed in a mixer (by hand) for a period of about 30 to 60 seconds in a first phase, and then allowed to partially set and then mixing was again begun on the product which had partially set in a shell around the outside, leaving a central core still in a liquid state. When the mixing was begun in the second phase, the set outer shell immediately went back in to solution, and after mixing again for about 30 to 45 seconds, the material was allowed to set completely.

TABLE-US-00002 TABLE 2 Sample Utilizing the above Base formulation the No. following materials were added by weight 1 boric acid (H.sub.3BO.sub.3) 1 g 2 H.sub.2SO.sub.4 0.05 g 3 H.sub.2SO.sub.4 0.05 g + boric acid (H.sub.3BO.sub.3) 0.25 g 4 H.sub.2SO.sub.4 0.05 g + (H.sub.3BO.sub.3) boric acid 0.50 g 5 H.sub.2SO.sub.4 0.05 g + boric acid (H.sub.3BO.sub.3) 0.25 g + an extra 2.25 g H.sub.2O 6 H.sub.2SO.sub.4 0.05 g + boric acid (H.sub.3BO.sub.3) 0.25 g + extra 7.5 g KH.sub.2PO.sub.4 (1.5x of base form.) 7 H.sub.2SO.sub.4 0.05 g + boric acid (H.sub.3BO.sub.3) 0.25 g + extra 15 g KH.sub.2PO.sub.4 (2x of base form.) 8 Same as the base, except the ratio is 1:2:1 of the MgO:MKP - (KH.sub.2PO.sub.4):stucco hemihydrate (CaSO.sub.4H.sub.2O)

[0105] For each of these samples, the resulting materials were analyzed for content, and homogeneity. Quantitatively, TABLE 3 below shows the results, and these are similar in format to those of TABLE 1 above.

TABLE-US-00003 TABLE 3 KMgPO.sub.46H.sub.2O K.sub.2Ca(SO.sub.4).sub.2H.sub.2O Unreacted MgO CaSO.sub.40.67H.sub.2O Sample (Struvite-K) (Syngenite) (Periclase) (Bassanite) no. (wt. %) (wt. %) (wt. %) (wt. %) 1 23.1 46.6 29.1 1.2 2 20.0 49.2 29.9 1.0 3 18.7 48.8 31.5 1.0 4 19.4 47.4 32.2 1.0 5 23.0 47.4 28.6 .9 6 20.1 33.9 42.2 3.9 7 58.8 24.0 7.3 9.9 8 52.8 29.8 16.1 1.3

[0106] In addition to the above quantitative results, several observations were made, including that the process yielded a formulation that was process friendly and yielded a board with a stronger core. It was also determined that changing the timing of the reactions by, for example, increasing mix time from one stage to two stages ranging from 45 to 90 seconds yielded a stronger core material with water resistance without need for wax or silicone. This is presumed to result form a higher Struvite-K yield. Finally, a close microscope examination of the set materials indicated that in many of the samples, crystallization occurred in a non-homogenous way in the final materials. That is, well formed crystallization occurred. The crystals, believed to be Struvite-K crystals, were determined to have formed in a boundary layer around the void spaces and between the voids and rest of the mixed product. A photomicrograph of one of these is shown in FIG. 1. As can be seen, the photomicrograph shows crystallization of the boundary between the void space and the surrounding matrix. This is understood to comprise a crystalline Syngenite/Struvite-K structure, resulting in better structural rigidity in the resultant composition.

[0107] In second batch of lab runs, a similar procedure was run as set forth above. The following TABLE 4 shows the sample constituents again using a base mixture as follows:

15 g MgO, 15 g MKP (KH.sub.2PO.sub.4), 0.15 g H.sub.2SO.sub.4, 0.25 g boric acid (H.sub.3BO.sub.3), 0.05 g dispersant. One difference in this base structure from the one in TABLE 2 above is that the amount of stucco (hemihydrate CaSO.sub.4.1/2H.sub.2O) was varied, requiring an increase in water as well.

TABLE-US-00004 TABLE 4 Sample Utilizing the above Base formulation the No. following materials were added by weight 1A 15 g stucco, 20 g water 2A 20 g stucco, 24 g water 3A 25 g stucco, 28 g water 4A 30 g stucco, 32 g water 5A 35 g stucco, 36 g water 6A 40 g stucco, 40 g water 7A 50 g stucco, 48 g water 8A 60 g stucco, 56 g water 9A 15 g stucco, 27 g water, an extra 15 g MKP 10A 50 g stucco, 34 g water

[0108] For each of these samples, the resulting materials were analyzed for content, and homogeneity. Quantitatively, TABLE 5 below shows the results, and these are similar in format to those of TABLES 1 and 3, above.

TABLE-US-00005 TABLE 5 Unreacted KMgPO.sub.46H.sub.2O K.sub.2Ca(SO.sub.4).sub.2H.sub.2O MgO CaSO.sub.40.67H.sub.2O CaSO.sub.40.5H.sub.2O * CaSO.sub.42H.sub.2O Sample (Struvite-K) (Syngenite) (Periclase) (Bassanite) (Bassanite) (Gypsum) no. (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) 1A 20.6 46.0 29.8 3.7 <0.1 <0.1 2A 14.0 45.1 27.6 <0.1 13.3 <0.1 3A x 56.6 26.9 <0.1 16.5 <0.1 4A x 57.4 21.5 <0.1 21.2 <0.1 5A x 50.7 21.5 <0.1 27.8 <0.1 6A x 44.0 21.4 <0.1 34.6 <0.1 7A x 43.4 14.9 <0.1 41.7 <0.1 8A <0.1 45.5 11.0 <0.1 43.5 <0.1 9A 66.2 27.0 6.8 x <0.1 <0.1 10A <0.1 2.5 <0.1 3.2 <0.1 94.4 * An analytical incongruity is apparent in two distinct forms of Bassanite: CaSO.sub.40.67H.sub.2O (47-964) and CaSO.sub.40.5H.sub.2O (Bassanite). These phases are similar and are both modelled as Bassanite.

[0109] Additional samples, deviating from the 1:1:1 ratio of the previous mixtures and not using the base composition of the first eight samples, were made up by use of the following formulations listed individually in TABLE 6 below:

TABLE-US-00006 TABLE 6 Sample MgO/MKP No. Constituent materials Ratio 11A 15 g MgO, 50.65 g mKP, 33.52 g water 1:3.38 (stoichiometric struvite production) 12A 15 g MgO, 7.5 mKP, 20 g stucco, 24 g water, + 2.0:1.0 0.15 g H.sub.2SO.sub.4 + 0.25 g boric acid (H.sub.3BO.sub.3) + 0.05 g dispersant 13A 15 g MgO, 7.5 mKP, 30 g stucco, 32 g water, + 2.0:1.0 0.15 g H.sub.2SO.sub.4 + 0.25 g boric acid (H.sub.3BO.sub.3) + 0.05 g dispersant 14A 15 g MgO, 7.5 mKP, 40 g stucco, 40 g water, + 2.0:1.0 0.15 g H.sub.2SO.sub.4 + 0.25 g boric acid (H.sub.3BO.sub.3) + 0.05 g dispersant 15A 15 g MgO, 7.5 mKP, 50 g stucco, 48 g water, + 2.0:1.0 0.15 g H.sub.2SO.sub.4 + 0.25 g boric acid (H.sub.3BO.sub.3) + 0.05 g dispersant

[0110] For each of these samples, the resulting materials were analyzed for content, and homogeneity. Quantitatively, TABLE 7 below shows the results, and these are similar in format to those of TABLES 1, 3, and 5 above.

TABLE-US-00007 TABLE 7 Unreacted KMgPO.sub.46H.sub.2O K.sub.2Ca(SO.sub.4).sub.2H.sub.2O MgO CaSO.sub.40.67H.sub.2O CaSO.sub.40.5H.sub.2O * CaSO.sub.42H.sub.2O Sample (Struvite-K) (Syngenite) (Periclase) (Bassanite) (Bassanite) (Gypsum) Mg(OH).sub.2 no. (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (Brucite) 11A No data available 12A <0.1 36.3 21.2 <0.1 19.9 <0.1 22.6 13A <0.1 33.2 10.8 <0.1 29.5 x 26.5 14A <0.1 27.0 4.3 <0.1 36.8 12.1 19.8 15A x 30.6 5.6 <0.1 <0.1 <0.1 25.9

[0111] As is evident in samples 12-15, a significant amount of the Magnesium oxide (MgO) failed to take part in the main reaction and instead generated a significant amount of a reaction by-product of a mineral identified as Brucite, (Mg(OH).sub.2), which was not present in the other samples.

[0112] A third lab test of 11 samples was conducted and a similar manufacturing procedure was run as set forth above. This test run was specifically directed to determine what variables in the production affect different specified characteristics of the resultant material compositions. The characteristics tested for across the different sample formulations were water absorption, shrinkage in a furnace muffle test that is a direct indicator of fire reissuance, and mechanical strength. The formulations were similar to those tested above, with the omission of the additives, such as boric acid, Polysiloxane, Lignosulfonate, Sulfuric acid, etc. To isolate the variable tested for, only the four essential constituents were utilized including the group magnesium oxide (MgO), Mono-Potassium Phosphate-MKP (KH.sub.2PO.sub.4), stucco (CaSO.sub.4.1/2H.sub.2O). The samples had the formulations with the water comprising 30 weight % of the final mixture:

TABLE-US-00008 TABLE 8 Sample The formulations of the following solid materials Same formulation including 30 weight ID only, by weight percent, and water added 30% percent of water A MgO 62.5, MKP (KH.sub.2PO.sub.4) 12.5, stucco 25.0, MgO 43.75, MKP (KH.sub.2PO.sub.4) 8.75, stucco 17.50, water water 30.0 B MgO 57.67, MKP (KH.sub.2PO.sub.4) 28.33, stucco 15.0, MgO 39.67, MKP (KH.sub.2PO.sub.4) 19.83, stucco 10.5, water water 30.0 C MgO 50.0, MKP (KH.sub.2PO.sub.4) 25.0, stucco 25.0, MgO 35.0, MKP (KH.sub.2PO.sub.4) 17.50, stucco 17.50, water water 30.0 D MgO 43.33, MKP (KH.sub.2PO.sub.4) 21.67, stucco 35.0, MgO 30.33, MKP (KH.sub.2PO.sub.4) 15.17, stucco 24.50, water water 30.0 E MgO 42.50, MKP (KH.sub.2PO.sub.4) 42.50, stucco 15.0, MgO 29.75, MKP (KH.sub.2PO.sub.4) 29.75, stucco 10.5, water water 30.0 F MgO 37.5, MKP (KH.sub.2PO.sub.4) 37.5, stucco 25.0, MgO 26.25, MKP (KH.sub.2PO.sub.4) 26.25, stucco 17.50, water water 30.0 G MgO 32.5, MKP (KH.sub.2PO.sub.4) 32.5, stucco 35.0, MgO 22.75, MKP (KH.sub.2PO.sub.4) 22.75, stucco 24.50, water water 30.0 H MgO 31.67, MKP (KH.sub.2PO.sub.4) 63.33, stucco 5.0, MgO 22.17, MKP (KH.sub.2PO.sub.4) 44.33, stucco 3.50, water water 30.0 I MgO 28.33, MKP (KH.sub.2PO.sub.4) 56.67, stucco 15.0, MgO 19.83, MKP (KH.sub.2PO.sub.4) 39.67, stucco 10.5, water water 30.0 J MgO 25.0, MKP (KH.sub.2PO.sub.4) 50.0, stucco 25.0, MgO 17.5, MKP (KH.sub.2PO.sub.4) 35.0, stucco 17.5, water water 30.0 K MgO 21.67, MKP (KH.sub.2PO.sub.4) 43.33, stucco 35.0, MgO 15.17, MKP (KH.sub.2PO.sub.4) 30.33, stucco 24.5, water water 30.0 L MgO 16.67, MKP (KH.sub.2PO.sub.4) 43.33, stucco 50.0, MgO 11.67, MKP (KH.sub.2PO.sub.4) 23.00, stucco 49.0, water water 30.0 M MgO 10.0 MKP (KH.sub.2PO.sub.4) 33.33, stucco 70.0, MgO 7.0 MKP (KH.sub.2PO.sub.4) 14.33, stucco 70.0, water water 30.0 N MgO 3.33, MKP (KH.sub.2PO.sub.4) 6.67, stucco 90.0, MgO 2.33, MKP (KH.sub.2PO.sub.4) 4.67, stucco 63.0, water water 30.0 O MgO 12.5, MKP (KH.sub.2PO.sub.4) 62.5, stucco 25.0, MgO 8.75, MKP (KH.sub.2PO.sub.4) 43.75, stucco 17.5, water water 30.0

[0113] As a visual aid, the solid constituents, by weight percent have been mapped in a ternary diagram as illustrated in FIG. 2. As can be seen from a comparison of the plots of the different formulations in the phase diagram, some like L, M and N are high stucco formulations, A-D are high MgO formulations, and group comprising H-N are high MKP formulations, while E, F and G are equally weighted between MgO and MKP. As can be seen by the linear progression of the connecting lines in the vertical directions, a pattern was intended to maintain as constant ratio between MgO and MKP while varying only the stucco content. In the horizontally aligned points, the stucco content is maintained constant and the ratio between MgO and MKP is varied. As result of the testing in the different formulations and trends seen from the compiled data, and the following major indications are provided as described below.

[0114] It should also be appreciated that the weight percent of water in the samples set forth above was nominally set at 30 weight percent, the percentage of water relative to the solid constituents can also be varied anywhere from 20 to 40 weight percent, with 30 weight percent being nominally used as a benchmark for having a sufficient amount of liquid solvent to initiate the reaction of the constituents.

[0115] It is also important to recognize that water temperature is a critical factor in the process. Specifically, the temperature of the water as it is added to the solid constituents is an important consideration as it affects the rate of reactivity of the constituents. An increase in the temperature of the water decreases the mix reactivity rate, and simultaneously increases the time that must pass for the slurry to set. Standard water temperature is about between 20.0 C. and 25 C. Thus, it is important to monitor and control the reaction rates to such rates that maintain the integrity of the resulting product, as too high a temperature, that is, over 50 C., can lead to cracking of the surface during the hardening process as the slurry sets. The main learning from this study is the inverse relationship of reaction rate when compared to initial water temperature.

[0116] From the testing regime, the following clear trends for characteristics have been determined: The inventive magnesium phosphate (Struvite-K/Syngenite) compositions exhibited significantly improved compression strength, water absorption and fire resistance compared to a simple Gypsum composition. Moreover, it has been determined that the product characteristics are indeed tunable with variables in the process parameters and raw material ratios and properties thereof. For example, those samples processed with lower water content exhibited higher compressive strength, higher fire and water resistance. Samples with higher shear rate/time exhibited higher compressive strength and marginal decrease in fire and water resistance. Shear rate and time is the vigor with which the mixture is mixed in a mixer, the amount of time the mixing process proceeds and whether the mixing was done by hand or mechanically.

[0117] Samples processed at cooler temperatures exhibited higher compressive strength and marginal decrease in fire and water resistance.

[0118] Samples with MgO calcined at higher temperature exhibited higher strength, samples with coarser MgO exhibited lower strength, which exhibits an opposite behavior to that of water absorption and fire shrinkage properties.

[0119] Additionally, it was noted that initial water temperatures were crucial in amount of and timing of delivery of the water.

[0120] Another sample production in an inline production run was attempted on an actual board forming line, in which the lab runs were scaled up by about 100 times to determine if the process is feasible for use in gypsum board production utilizing the inventive material combinations. Essentially the same formulations were utilized, with the obvious exception that all the amounts were scaled up, and a much larger mixer and reactor vessel or chamber was required. The procedure also needed to be modified in significant ways to enable the continuous, rather than batch, production of the inventive material compositions for use in a board line running at almost normal speed of running or a round 40 feet per minute.

[0121] Certain additional equipment was required for this production run not needed in the lab runs, including a tank reactor, a mixer, one or more pumps, a roller coater, perhaps two one for each of the two surface layers, and a core gypsum mixer and pump for providing a continuous flow of the core gypsum, that is, the lightweight core gypsum, that will make up the central layer that will ultimately comprise the central or core layer having little if any of the Struvite-K and Syngenite reaction products. Thus, the final desired product is to be a surface layer coated with the inventive material compositions wrapped around a gypsum core.

[0122] The procedure to manufacture the surface layer coatings is essentially the same as those described above, except adjustments are required to be made for the vastly increased scale of the constituent materials. The following step-by-step procedure is expected to produce the necessary coating layer:

[0123] Pre-mix the solid mixture, comprising a 1:1:1 ratio, that is, MgO:MKP-(KH.sub.2PO.sub.4):stucco (hemihydrate CaSO.sub.4.1/2H.sub.2O) the pre-mix phase to last form between 30 to 60 seconds. To ensure that enough of the mixture is made, it is expected that about a 15 kg amount of each of the base constituents is made. A proportional amount of siloxane and a defoamer, and a dispersant, such as polynapthalene sulfonate, may be added to this mixture.

[0124] Add water in about the same proportion, or about 17 kg.

[0125] Mix the resulting slurry for between 30 to 60 seconds in the large continuous mixer. After 15 seconds of mixing, the mixture started to solidify. It has been found that continued mixing will re-liquify the mixture. This is Phase I mixing.

[0126] Upon finishing with this initial mixing time, a timing sequence was commenced. Each minute after this initial Phase I mixing time, the mixture was again mixed vigorously for 5 second periods separated by 55 second intervals. This is the Phase II mixing.

[0127] The formulation used in the production run causes the product to set-up anywhere from 5-20 minutes after the water is added to the powders. Due to the type of mixer used, however, the mixing occurred unevenly, no product was obtained out of the mixer/reactor in any appreciable amounts fro technical reasons. Further testing is needed to validate the scale up and continuous production run model.

[0128] The invention herein has been described and illustrated with reference to the embodiments of FIGS. 1-3, but it should be understood that the features and operation of the invention as described are susceptible to modification or alteration without departing significantly from the spirit of the invention. For example, the variations in starting materials of the various elements, or the specified reaction conditions may be altered to fit specific applications and desired yields. Also, additional variations may be introduced to provide differences in the resulting materials. For example, alternative additives to the starting constituents may include, in combination and or permutations of the listing herein, Boric acid, Polysiloxane defoamer, Lignosulfonate, Sulfuric acid, deionized water, tap water, and others as these become known to affect the reactions.

[0129] In addition, the mixing process and speed may be varied to obtain more optimal desired results. Other variables that may be utilized to optimize results are used natural instead of Synthetic stucco, the order and timing of additions and ingredients may be varied, and with the introduction of productions runs, mechanical mixing of the constituents in for example, pipe reactors or tube of a given length containing static mixers therein may enable multi-stage mixing of the constituent to provide a constant flow for in line flow mixing and just in time delivery to the gypsum board forming table. Other variables that may have an effect on resulting ratios and products may include varying the sate as well as the ratio of the raw constituent materials. These may include varying the addition rate, temperatures of the constituents, timing of additions, particle size, mix time, and other factors that may be determined as experience is gained with the reaction processes.

[0130] Accordingly, the specific embodiments illustrated and described herein are for illustrative purposes only and the invention is not to be considered as being limited except by the following claims and their equivalents.