Foamed glass beads

Abstract

Foamed glass beads, including: heated preform pellets, wherein the preform pellets comprise a pelletized pre-foamed bead paste comprising a glass powder that has a predetermined mesh size, a hydrated foaming agent, a hydrated binder, a flux and a solvent; where the combined flux and glass powder have a lower melting point than the melting point of the glass powder alone, The flux forms a seal around particles of the glass powder and the hydrated foaming agent. the flux has a lower melting point than glass and The hydrated binder has a thermal decomposition temperature of 450 degrees Celsius or below.

Description

TECHNICAL AREA OF INVENTION

[0001] This invention relates to foamed glass beads and in particular to an improved composition of foamed glass beads. TECHNICAL BACKGROUND

[0002] Foamed glass beads are used in concrete aggregates to improve insulation, reduce material weight (which is advantageous for transportation), and enable faster construction times. However, current compositions and manufacturing processes limit the size and strength of available beads. An improved composition and manufacturing process are needed to increase the compressive strength of foamed glass beads and allow for a wider range of sizes.

[0003] Furthermore, in scenarios requiring improved properties for thermoplastic-based products, solutions are currently employed in which the thermoplastic is modified by adding fillers such as hollow glass beads, glass fibers, or minerals like talc and calcium carbonate. Adding these fillers makes the composite material (i.e., the compound) stiffer and more heat-resistant. However, these additives all have drawbacks. Solid glass beads, glass fibers, talc, and calcium carbonate are relatively dense (approximately 2.7 g / cm³). 3This affects how easily the compound can be transported to production facilities or its final destination. The heavier the materials, the more fuel and electricity are consumed during transport. If the material is used in an end product that is itself a means of transport (e.g., motor vehicles or aircraft, or their components), fuel and electricity consumption will be continuously higher throughout the product's lifespan. Hollow glass beads, however, do solve the fuel and electricity consumption problem because they have a lower density (around 0.6 g / cm³). 3 ), but they are brittle and break easily. Additionally, all these materials are primary materials that consume non-renewable resources. Therefore, a filler is needed that is less dense than current fillers and more durable than hollow glass beads. SUMMARY

[0004] This disclosure relates to foamed glass beads and, in particular, an improved composition and process for producing foamed glass beads for use as an additive and for other applications. In one aspect, the disclosure provides foamed glass beads that can be produced from heated preform pellets, wherein the preform pellets comprise a pelletized, pre-foamed bead paste, which includes glass powder having a predetermined mesh size, a hydrated foaming agent, a hydrated binder, a flux, and a solvent. The glass may be derived from cullet ground into glass powder. The combined flux and glass powder may have a lower melting point than the melting point of the glass powder alone, thereby lowering the melting point of the glass powder.The flux can form a seal around particles of the glass powder and the hydrated foaming agent and has a lower melting point than the glass powder. The flux can also help the glass powders bond together after melting. The hydrated binder can have a thermal decomposition temperature of 450 degrees Celsius or less and therefore burn off during the heating process. As such, the hydrated binder can keep the glass and the hydrated foaming agent in solution. During heating, the flux and the foaming agent can be incorporated into the glass.

[0005] In some cases, the foamed glass beads may also include an outer, non-porous skin layer that can contain the glass powder and decomposed flux components. Furthermore, in some cases, the hydrated foaming agent may have a thermal decomposition temperature between 600 and 950 degrees Celsius.

[0006] In some cases, a large number of sealed air inclusions may occur as a result of the incorporation of the glass powder with the flux, whereby the hydrated foaming agent may enable the production of gas during tempering, and the gas may be able to migrate to the large number of sealed air inclusions to enlarge them into bubbles in the preform pellets.

[0007] In some cases, the heated preform pellets may further include a sealant. The sealant and flux may be cross-linked polymers, the cross-linked polymers being configured to immobilize soluble and insoluble components, and the sealant having a thermal decomposition temperature of 450 degrees Celsius or less. As such, the sealant can create a barrier within the preform pellets to limit the migration of soluble and insoluble components, while allowing solvent and solvent vapor to escape during the drying process. Additionally, the sealant may burn off during the heating process. In some cases, the cross-linked bonds may be hydrogen bonds. And in some cases, the sealant may be an adhesive compound, which may include polyvinyl acetate, ethanol, water, and acetate.In some cases, the sealant may be an alginate gel. Furthermore, the alginate gel may contain sodium alginate and calcium chloride.

[0008] In some cases, the interiors of each of the foamed glass beads may be characterized by cavities surrounded by walls of a solid matrix. In some cases, the solvent may be water. In some cases, the hydrated foaming agent may be bentonite. In some cases, the flux may contain boron and be selected from the group consisting of sodium borate, sodium tetraborate, disodium tetraborate, and combinations thereof. In some cases, the hydrated binder may comprise a sugar that burns off upon heating, and the sugar may be selected from the group consisting of xanthan gum, guar gum, and combinations thereof. In some cases, the foamed glass beads may be incorporated into a plastic product, with the foamed glass beads being uniformly distributed throughout the plastic product and comprising between 15% and 80% of the incorporated product by volume.

[0009] In another aspect, the disclosure provides a method for producing foamed glass beads, wherein the method comprises hydrating a foaming agent; hydrating a binder; mixing a glass powder with the hydrated foaming agent and the hydrated binder to produce a premix, wherein the glass powder has a predetermined mesh size; adding a solvent to the premix and mixing to produce a flowable preform mixture; incorporating a flux into the flowable preform mixture to produce a pre-foamed bead paste; pelletizing the pre-foamed bead paste to produce preform pellets; and heating the preform pellets until particles of the glass powder from the preform pellets are sintered together and the preform pellets become molten beads.and includes removing the molten beads from the heat to cool them into foamed glass beads. In some cases, the preform pellets can be heated to between 800 and 1000 degrees Celsius.

[0010] In some cases, the interiors of each foamed glass bead may be characterized by cavities surrounded by walls of a solid matrix. In some cases, the solvent may be water. In some cases, the hydrated foaming agent may be bentonite. In some cases, the flux may contain boron and be selected from the group consisting of sodium borate, sodium tetraborate, disodium tetraborate, and combinations thereof.

[0011] In some cases, the process may further include mixing a sealant with the flowable preform mixture, the sealant dissolving between and mixing with the particles. The sealant may be an adhesive compound comprising polyvinyl acetate, ethanol, water, and acetate. Alternatively, the sealant may be an alginate gel. The alginate gel may be produced by mixing in solutions of sodium alginate and calcium chloride.

[0012] In some cases, before heating the preform pellets, the glass powder may be between 93.3% and 99.6% by weight, the foaming agent may be between 0.31% and 4.67% by weight before hydration, the binder may be between 0.062% and 1.17% by weight before hydration, and the flux may be between 0.01% and 0.3% by weight. More precisely, the glass powder may be between 96.5% and 99.2% by weight, the foaming agent may be between 0.6% and 2.4% by weight before hydration, the binder may be between 0.12% and 0.6% by weight before hydration, and / or the flux may be between 0.02% and 0.15% by weight. In some cases, the process may further include a sealant in the flowable preform mixture, wherein the sealant dissolves between particles and mixes with them, the sealant comprising up to 0.56% by weight.More precisely, the sealant can amount to up to 0.29% by weight.

[0013] In some cases, the preform pellets may be suspended in a granular medium that remains separate from the preform pellets during heating. In some cases, the hydrated binder may comprise a sugar that chars during heating, and the sugar may be selected from the group consisting of xanthan gum, guar gum, and combinations thereof. In some cases, the hydrated binder may be xanthan gum.

[0014] In some cases, the process may further include drying the preformed pellets before heating. Before drying, the solvent content can range from 20.0% to 50.0% by weight. More precisely, the solvent content can range from 30.0% to 37.6% by weight.

[0015] In some cases, the process may further include suspending the preform pellets on a bed of a bead support material with a higher melting point than that of the preform pellets; and adding additional bead support material to the preform pellets, wherein the bead support material may be aluminum hydrate powder. Furthermore, the molten beads may be separated from the bead support material by mechanical means.

[0016] In some cases, the hydrated foaming agent can decompose during heating, creating gas nucleation sites within the molten beads. Furthermore, the hydrated foaming agent may be bentonite clay and release gas upon heating. This gas can migrate from the bentonite clay to the nucleation sites, creating gas bubbles within the molten beads. The flux may also contain boron. Additionally, the foamed glass beads may exhibit uniformly distributed bubbles upon cooling.

[0017] In some cases, the process may further include introducing the foamed glass beads into a molten plastic; and cooling the plastic with the foamed glass beads evenly distributed within it. The foamed glass beads may comprise 15–80% of the combined product by volume.

[0018] The foregoing summary is not intended to describe every single example or embodiment of the disclosure. The following description illustrates, in particular, various exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following description should be read with reference to the drawings. The drawings, which are not necessarily to scale, are examples and are not intended to limit the scope of the disclosure. The disclosure may be more fully understood by considering the following description in relation to various examples in conjunction with the accompanying drawings, in which: Fig. Figure 1 illustrates a cross-sectional view of a concrete slab with embedded foamed glass beads; Fig. 2 illustrates a cross-sectional view of a concrete block with embedded foamed glass beads; Fig. Three embodiments of the foamed glass beads in different matrices are illustrated; Fig. Figure 4a illustrates a cross-sectional view of a standard aggregate; Fig. 4b illustrates a cross-sectional view of the improved engineered aggregate including the disclosed foamed glass beads; Fig. 5a is a schematic cross-sectional view of a portion of a foamed glass bead, illustrating cavities and walls. Fig. 5b is an illustration of a portion of a foamed glass bead, illustrating cavities and walls of a low-density bead with approximately 0.5 specific gravity; Fig. 5c is an illustration of a portion of a foamed glass bead, illustrating cavities and walls of a bead with a mean density of approximately 1.0 specific gravity; Fig. Figure 6 illustrates how the components of the foamed glass beads interact when no binder is present; Fig. Figure 7 illustrates how the components of the foamed glass beads are suspended by the binder in a solvent before heating; Fig. Figure 8 illustrates how the components of the foamed glass beads are held in place by a sealant while the solvent is removed; Fig. Figure 9 illustrates that the flux of the foamed glass beads undergoes a thermal transformation during initial heating phases to create a seal around the remaining components; Fig. Figure 10 illustrates how the glass powder particles soften during later stages of heating and adhere to other glass powder particles along the sealed boundaries created by the flux; Fig. 11 illustrates the production of gas and bubbles by decomposition of the foaming agent during later stages of heating; Fig. 12 illustrates the expanded gases, uniformly shaped cavities and the introduction of the remaining components with the glass during later heating phases; Fig. 13 illustrates the structure of the foamed glass beads after heating with glass matrices and internal cavities; Fig. 14 preformed beads of different sizes illustrated before and after heating; Fig. 15 illustrates a top and side view of a foamed glass bead which is irregularly shaped, has open external structures and has internal cavities of varying sizes; Fig. 16 is a cross-sectional view of a foamed glass bead, illustrating the glass matrix and cavities present in the internal structure; Fig. 17 is a cross-sectional view of a foamed glass bead, illustrating the glass matrix and cavities present in the internal structure; Fig. 18 is a cross-sectional view of a foamed glass bead, illustrating the glass matrix and cavities present in the internal structure; Fig. Figure 19 illustrates a densely packed group of foamed glass beads; Fig. 20 illustrates the texture of the surface of a foamed glass bead; and Fig. Figure 21 is a flowchart for a process for producing the foamed glass beads. DETAILED DESCRIPTION

[0020] The present disclosure relates to foamed glass beads and, in particular, to an improved composition and process for producing foamed glass beads. Various embodiments are described in detail with reference to the drawings, in which the same reference numerals may be used to represent identical parts and arrangements in the different views. The reference to various embodiments does not limit the scope of the system and methods disclosed herein. Examples of structure, dimensions, and materials may be illustrated for the various elements, and those skilled in the art will recognize that many of the examples provided have suitable alternatives that may be used.Any examples set forth in this description are not intended to be limiting and merely represent some of the many possible embodiments of the systems and methods. It is understood that various omissions and substitutions with equivalents will be considered where circumstances suggest or make it expedient, provided that these are intended to cover applications or embodiments without departing from the spirit or scope of the disclosure. It is further understood that the language and terminology used herein serve the purpose of the description and should not be regarded as limiting.

[0021] Fig. Figure 1 illustrates a cross-sectional view of a concrete slab with embedded foamed glass beads. When used, foamed glass beads can be added to concrete to increase the insulating properties of the concrete aggregate, increase the strength of the concrete, reduce the drying time of the concrete to allow for faster construction times, and reduce the weight of the overall aggregate to allow for more efficient transport of building materials to construction sites (for example, a cubic yard of concrete can weigh from 3,750 to 4,050 pounds, whereas a cubic yard of concrete with foamed glass beads can weigh from 1,530 to 2,120 pounds).

[0022] Additional views of the pearl are provided. Fig. Figure 2 illustrates a cross-sectional view of a concrete block with embedded foamed glass beads. Fig. Figure 3 illustrates embodiments of the foamed glass beads in different matrices (polymer foam matrix 300, non-foamed polymer matrix 310, beads adhering to one another using an epoxy adhesive 320, a polymer foam loaf 330 and a cement matrix 340). Fig. Figure 4a illustrates a cross-sectional view of a standard aggregate. Fig. Figure 4b illustrates a cross-sectional view of the improved engineered aggregate including the disclosed foamed glass beads. Fig. Figure 5a is a schematic cross-sectional view of a portion of a foamed glass bead, illustrating cavities 510 and walls 520. Fig. Figure 5b is an illustration of a portion of a foamed glass bead, illustrating cavities and walls of a low-density bead with approximately 0.5 specific gravity. Fig. Figure 5c is an illustration of a portion of a foamed glass bead, showing cavities and walls of a bead with a mean density of approximately 1.0 specific gravity. Fig. Figure 6 illustrates how the components of the foamed glass beads interact when no binder is present. Fig. Figure 7 illustrates how the components of the foamed glass beads are suspended by the binder in a solvent before heating. Fig. Figure 8 illustrates how the components of the foamed glass beads are held in place by a sealant while the solvent is removed. Fig. Figure 9 illustrates that the flux of the foamed glass beads undergoes a thermal transformation during initial heating phases to create a seal around the remaining components. Fig. Figure 10 illustrates how the glass powder particles soften during later stages of heating and adhere to other glass powder particles along the sealed boundaries created by the flux. Fig. Figure 11 illustrates the production of gas and bubbles through decomposition of the foaming agent during later stages of heating. Fig. Figure 12 illustrates the expanded gases, uniformly shaped cavities, and the introduction of the remaining components with the glass during later heating phases. Fig. Figure 13 illustrates the structure of the foamed glass beads after heating with glass matrices and internal cavities. Fig. Figure 14 illustrates preformed beads of different sizes before and after heating. Fig. Figure 15 illustrates a top and side view of a foamed glass bead that is irregularly shaped, has open external structures and internal cavities of varying sizes. Fig. Figures 16-18 are cross-sectional views of a foamed glass bead, illustrating the glass matrix and cavities present in the internal structure. Fig. Figure 19 illustrates a densely packed group of foamed glass beads. Fig. Figure 20 illustrates the texture of the surface of a foamed glass bead. Fig. 21 is a flowchart for a process for producing the foamed glass beads (diamond-shaped steps indicate a point in the process where a decision needs to be made).

[0023] In general, the bead can have a surface skin layer and a porous interior. More specifically, the bead can contain glass, a foaming agent, a binder, an optional sealant, a flux, and a solvent. The foaming agent can be a hydrated foaming agent. Similarly, the binder can be a hydrated binder that keeps the glass and the hydrated foaming agent in solution. Generally, the glass powder, the hydrated foaming agent, the hydrated binder, the optional sealant, the flux, and the solvent can be mixed together to create a preform material, which is then pelletized to produce preform pellets. The preform pellets can subsequently be annealed.The composition of the preform pellets before tempering may mainly contain glass, which is 93.3% to 99.6% by weight, a foaming agent, which is between 0.31% and 4.67% by weight before hydration, a binder, which is between 0.062% and 1.17% by weight before hydration, a sealant, which is up to 0.56% by weight, and a flux, which is between 0.01% and 0.3% by weight.

[0024] In alternative embodiments, the bead can contain glass, a voiding agent comprising a foaming agent and a flux, water, and a binder. The general manufacturing process involves mixing the voiding agent, water, and a binder to produce preform pellets. The preform pellets can then be annealed. The composition of the preform pellets before annealing can mainly consist of a voiding agent between 0.25% and 1% by weight (for example, 0.5%), water between 30% and 50% by weight (for example, 40%), a binder less than 1% by weight, and glass powder between 40% and 60% by weight. In the dried state, the glass content can range from 93.3% to 99.6% by weight.

[0025] In addition to the unique composition of the foamed glass beads, the process by which they are manufactured is also unique and novel.More specifically, the process involves the steps of hydrating a foaming agent, hydrating a binder, mixing a glass powder with the hydrated foaming agent and the hydrated binder to create a premix, adding a solvent to the premix and mixing to create a flowable preform mixture, mixing a flux into the flowable preform mixture to create a pre-foamed bead paste, pelletizing the pre-foamed bead paste to produce preform pellets or beads, heating the preform pellets / beads until particles of the glass powder from the preform pellets are sintered together and the preform pellets become molten beads, and removing the molten beads from the heat to cool them into foamed glass beads.When the sealant is used, the process also includes the step of mixing a sealant into the flowable preform mixture, whereby the sealant dissolves between particles and mixes with them.

[0026] In some cases, the pre-expanded bead paste can be dried before or after pelletizing. After drying (in some cases using heat), the bead paste may release dust, and the glass powder may be exposed and have sharp edges. Therefore, a solvent (for example, water) can be added back in. The solvent may be 0.5–25% (for example, 1%) by weight (or in some cases by volume) and can allow the bead paste to crumble uniformly without clumping, reduce the amount of dust, and, if the solvent is mixed in, the mixing process can cause the glass powder to be smoothly rolled into the preformed pellets or beads. After the solvent has been added, the beads can then be heated as further described herein.

[0027] In alternative embodiments, the process includes the steps of adding a foaming agent to a flux to create a cavity representative, drying the cavity representative, grinding the cavity representative into a powder, adding water to the powdered cavity representative and mixing it in to create a primary preform mixture, mixing a glass powder into the primary preform mixture to create a secondary preform mixture, mixing a binder into the secondary preform mixture to create a final preform mixture, pelletizing the final preform mixture to produce preform pellets, heating the preform pellets until particles of the glass powder from the preform pellets are sintered together and the preform pellets become molten beads, and removing the molten beads from the heat to cool them to foamed glass beads.The details of the composition and process are set out below.

[0028] The beads can be approximately spherical, but are not limited to this shape. For example, the beads can be elongated, cylindrical, or irregularly shaped, as in Fig. 15 illustrated by beads 1510 and 1520. The beads can also have a range of sizes, as shown in Fig. Figure 14 illustrates this. For example, they can have diameters of fractions of millimeters (e.g., a 0.05 mm bead produced from a 0.035–0.04 mm preform pellet, or a 7 mm bead 1410 produced from a 5–5.5 mm preform pellet 1420 heated to 950 degrees Celsius and held at that temperature for 15 minutes) or they can have diameters of several centimeters (e.g., a 15 mm bead 1430 produced from a 10 mm preform pellet 1440 heated to 950 degrees Celsius and held at that temperature for 15 minutes). The size of the final foamed glass bead can be determined by the mass of the premix used, the relative concentrations of the components, and the rate and duration of heating the preform pellets. In general, the diameter of the final, foamed bead can be approximately one third larger than the diameter of the preformed pellet.

[0029] In general, a cross-section of the beads shows that their internal structures comprise a series of cavities surrounded by walls, as in the Fig. Figures 5 and 15-18 illustrate this. The shape of the cavities can be round, oval, rounded squares, or irregularly shaped. The cavities may be uniform in size and distribution, or they may be denser in some places (i.e., have smaller, more numerous cavities) compared to others, as shown in Figures 5 and 15-18. Fig. Figure 15 illustrates where cavities of variable size are present in the internal structure of beads 1510 and 1520. This varying density may occur due to uneven heating. The cavities may be created by outgassing from the thermal decomposition of the foaming agent during heating. Additional components may undergo chemical and / or physical changes that also contribute to outgassing. The walls surrounding the cavities comprise sintered glass and any remaining solid components left behind after the thermal decomposition during heating the beads.

[0030] While the foamed glass beads are generally described herein as spherical with uniformly distributed internal cavities, the size of the beads, their density, and their compressive strength can be determined and adjusted by the mass of premix used per bead, the relative concentrations of the components (glass, foaming agent, binder, sealant, flux, solvent, etc.) in the formulation, the process parameters for the beads, and the bead formation process. Processing conditions, such as heating, can influence the size of the cavities within the foamed glass beads, the degree of foaming that occurs, and the compressive strength of the foamed glass beads.In general, preformed pellets heated for a shorter period are more fragile and have smaller void sizes, whereas pellets heated to the target temperature of 800-1000 degrees Celsius are structurally more stable and have larger and more regular voids. Fig. Figure 17 illustrates a 16 mm bead that was heated at 950 degrees Celsius for fifteen minutes. Fig. Figure 18 illustrates an 8 mm bead that was heated to 950 degrees Celsius and subsequently removed from the heat. The shape of the final foamed glass beads can be determined partly by their size and partly by their initial shape. In particular, smaller beads may tend to assume a variety of shapes, resulting in nearly spherical foamed glass beads, whereas larger beads may be more constrained by their initial shape.

[0031] The glass can be derived from broken glass, which is crushed into a fine glass powder of a predetermined size or sizes. In some cases, the mesh size can be as low as 120 mesh. In other embodiments, the mesh size can range from 250 to 400 mesh. The glass can be soda-lime glass, which is recycled from food and beverage packaging. Soda-lime glass is chemically inert and has high compressive strength, which is useful for incorporation into concrete. However, when soda-lime glass is crushed into broken glass and finer particles, it exhibits an irregular shape, as seen in [example missing]. Fig. Figure 4a illustrates what can cause problems in certain types of use. One way to address this is to increase the cement-to-glass ratio; however, this increases the cost and weight of the final concrete mix and reduces the overall strength of the cured structure. An alternative solution is to reshape the broken glass into more rounded forms. However, since the energy required to melt pure glass is high, this additional step is not efficient.

[0032] As proposed below, cullet can be efficiently converted into an aggregate and reformed into spherical shapes while retaining many of the advantageous properties of glass. More specifically, recycled end-user glass can be pulverized, converted into an aggregate, and annealed using high heat for a short period. The high heat sinters and melts a pulverized glass preform into a foamed bead with varying density, but generally in the range of 0.05 g / cc up to that of solid glass, 2.6 g / cc (for example, 1 g / cc), providing high compressive strength (for example, 1,000 psi, 2,000 psi, 3,000 psi, or even more, up to 70,000 psi). Compared to known foamed glass beads, which require 300 psi for a bead with a density of 1 g / cc and a diameter of 3 mm, the disclosed foamed glass beads can be 20.000 psi for a bead with a density of 1 g / cc and a diameter of 3 mm. Even for foamed glass beads, which have a low density of 0.2 g / cc and a diameter of 3-6 mm, the compressive strength can reach 100 psi. Before heating / tempering, the powdered glass can have a solids content between 93.3% and 99.6% (for example, 96.5% to 99.2%) by weight of the preformed pellet.

[0033] After heating / tempering, the final foamed glass bead can be added to the concrete to achieve the desired effects outlined above. In other cases, as mentioned above, the final foamed glass bead can be added to molten thermoplastics as a modifier to produce plastic products (i.e., compounded plastics) that exhibit increased stiffness / rigidity and better stability at elevated temperatures than thermoplastics alone.

[0034] For example, an extruder can heat a thermoplastic pellet to melt it. While it is in the extruder, a compounder can introduce additives, such as, but not limited to, the foamed glass beads disclosed herein, as well as color(s) and / or stabilizers. The molten compound can then be homogenized for a predetermined time or over a predetermined distance (for example, the length of the extruder), after which it can be cooled, resolidified, and cut into pellets. The pellets can then be more easily melted for their final injection molding, extrusion, or shaping because the foamed glass beads have hollow cavities that do not require heating or cooling like the thermoplastic material. Additionally, due to the incorporation of foamed glass beads into the compound, the final plastic product will cool down faster at the surface (i.e.,(The skin formation time can be reduced) and it will be able to be ejected from a mold faster, thus reducing the time required to produce each part in production (i.e., the cycle time).

[0035] The final product is a compound that is stiffer and more heat-resistant than the original thermoplastic material. Additionally, the density of the foamed glass beads can be approximately 0.6 g / cc, which is lighter than most current additives (for example, solid glass beads, solid glass fibers, talc, and calcium have a density of about 2.7 g / cc, and the lightest unfilled plastics have a density of about 0.9 g / cc) and considerably stronger than additives of similar density (for example, hollow glass beads have a density of about 0.6 g / cc, but they are brittle; their comminution strength is about 250 psi compared to the comminution strength of at least 1,000 psi for the disclosed foamed glass beads). Therefore, the foamed glass beads are lighter than all pure thermoplastics as well as most thermoplastic compounds and stronger than thermoplastic compounds of similar density / weight. EXECUTION FORM 1

[0036] As mentioned above, the interior of foamed glass beads can be characterized by cavities surrounded by walls of a solid matrix, as in Fig. 5a illustrates. Fig. Figure 5b shows a bead with a lower density (0.5 specific gravity) in which the cavities take on a honeycomb-like appearance due to the higher ratio of cavities (enclosed gas) to the glass matrix. Fig. Figure 5c shows round cavities (enclosed gas) which are typical for a lower ratio of cavities to glass matrix (1.0 specific gravity).

[0037] One embodiment of the aggregate comprising the foamed glass beads may contain powdered glass (as described above), a hydrated foaming agent, a hydrated binder, a flux, and a solvent. In some cases, a sealant is also present. The glass may be derived from cullet ground into glass powder. This glass powder may be combined with the hydrated foaming agent, the hydrated binder, the optional sealant, the flux, and the solvent to produce a preform material. The preform material may then be pelletized to produce preform pellets. The hydrated binder may keep the glass and the hydrated foaming agent in solution and may also bind the preform pellets together during (optional) drying.During the drying process, any sealant can create a barrier throughout the preform pellets to limit the migration of soluble and insoluble components, while allowing the solvent and vapors to escape. Once the preform pellets are dry, they are heated to a predetermined temperature (for example, 950 degrees Celsius). The addition of flux to the preform pellets helps lower the melting point of the glass powder. It also creates a seal around the combined glass powder and hydrated foaming agent, and it helps the glass powder bond together once the powder particles have melted. During heating, the hydrated binder and, if present, the sealant are burned off, while the flux and hydrated foaming agent are incorporated into the glass powder.After the heating process is complete, the foamed glass beads are formed.

[0038] As mentioned above, the foaming agent can be a hydrated foaming agent. More precisely, a solvent (for example, water) can be added to a foaming agent to hydrate it until it forms a thick paste. In some cases, the hydrated foaming agent can be a metal-coordinated silicate, such as, but not limited to, bentonite, an absorbent clay. Bentonite clay can produce a thick, viscous emulsion that suspends and separates the glass powder particles, thereby creating a homogeneous, free-flowing mixture that is ideal for dispensing or forming preforms.In other embodiments, salts may be used in which the anion or cation can thermally decompose, releasing a volatile compound or gas, such as, but not limited to, mono-, di-, and trivalent salts of carbonates (such as lithium carbonate), nitrates, azides, or other thermally decomposing anions. Volatile anions such as ammonium salts may also be used. Organic compounds that are volatile or thermally decompose / combust at the temperatures described herein may also provide the gas to form the cavities. Furthermore, alternative clays (for example, kaolin) may be used instead of bentonite. As mentioned above, the hydrated foaming agent may dehydrate during the drying process, which may occur prior to heating.

[0039] The purpose of the hydrated foaming agent is to decompose during heating (for example, when temperatures are between 600 and 700 degrees Celsius) in order to generate gas bubbles within the glass matrix, as in Fig. Figure 11 illustrates this. These gas bubbles can then migrate to air inclusions within the preformed pellets and enlarge these air inclusions into bubbles / cavities. As the gas expands during subsequent heating stages (450-1000 degrees Celsius), the cavities become more uniform, as shown in Figure 11. Fig. Figure 12 illustrates this process, and the glass powder particles form walls around the cavities. Additionally, as described in more detail below, the flux, foaming agent, optional sealant, and binder are either burned off or incorporated into the glass. Then, when the bead is removed from its heat source and cools, the glass matrix anneals and the structure hardens, as shown in Figure 12. Fig. Figure 13 illustrates this. The internal structures reinforce the outer surface.

[0040] More specifically, air inclusions can be created and / or removed by introducing a flux into the glass powder. Gas bubbles generated from the decomposing foaming agent may migrate to the air inclusions and expand their size, creating larger bubbles / voids within the molten pellets. Even with the presence of a sealant that prevents air inclusion migration, gas bubbles generated from the decomposing foaming agent may still migrate to these air inclusions. Due to the introduction of the hydrated foaming agent through the preform pellets, the final foamed glass beads may exhibit uniformly distributed bubbles after cooling. The foaming agent can comprise between 0.31% and 4.67% (for example, 0.6% to 2.4%) by weight of the preform pellet before heating / tempering, prior to hydration.

[0041] In addition to the foaming agent, the foamed glass beads may include a binder. Similar to the foaming agent, the binder may also be hydrated. For example, a solvent (such as water) may be added to a binder to hydrate it until it forms a thick paste. In some embodiments, the hydrated binder may include a sugar, such as, but not limited to, xanthan gum, guar gum, polysaccharides, polyol sugar alcohols, and combinations thereof. The hydrated binder may also include non-sugar gelling agents (such as calcium alginate), provided they are capable of holding insoluble materials in place in three-dimensional space. Other materials that may function as binders include, but are not limited to, agar, gelatin, agarose, polyacrylamide, and combinations thereof.As mentioned above, the hydrated binder can dehydrate during the drying process, which can occur before heating. The hydrated binder can burn off completely during heating. Alternatively, some (or all) of the binder can be incorporated into the molten preform during heating. The binder can comprise between 0.062% and 1.17% (for example, 0.12% to 0.6%) by weight of the preform pellet before heating / tempering.

[0042] The purpose of the binder is to keep the insoluble components (i.e., the glass and the foaming agent) in solution. As in Fig. As illustrated in Figure 6, the inclusion of only glass and a foaming agent in a solution (without the binder) causes these components to settle out of the solution, making it difficult to form a foamed glass bead. Therefore, the addition of a binder allows the components to remain suspended in the solvent and to be held in a three-dimensional position during the pre-foamed bead formation process, as shown in Figure 6. Fig. 7 illustrates.

[0043] As detailed below, the hydrated foaming agent and hydrated binder can be mixed with the glass powder to create a premix paste. Once the premix paste is prepared, a solvent (e.g., water) can be added and mixed in to create a flowable preform mixture. Flowability can be better controlled by prehydrating the foaming agent and binder. The solvent content can range from 20.0% to 50.0% (e.g., 30.0% to 37.6%) by weight of the preform pellet before drying and heating / tempering.

[0044] Once the preform is flowable, a sealant can be added and mixed in until it dissolves and blends between the particles. In some embodiments, the sealant may be an adhesive compound, such as, but not limited to, a combination of polyvinyl acetate, ethanol, water, and acetate. In other embodiments, the sealant may be an alginate gel, such as, but not limited to, a combination of sodium alginate and calcium chloride solutions mixed together. If present, the sealant may comprise up to 0.56% (for example, 0% to 0.29%) by weight of the preform pellet before heating / tempering.

[0045] The sealant can help hold the preform pellets together and can create a barrier throughout the preform pellet to limit the migration of soluble and insoluble components, while allowing water and / or water vapor to escape from the preform pellets. Furthermore, the sealant can retain suspended solids (e.g., the foaming agent, flux, and other soluble and insoluble components) within the bead and prevent these solids from migrating to the edge of the preform pellets as the pellets air dry prior to tempering and the solvent is released and / or evaporates, as described in [reference to relevant document / reference]. Fig. Figure 8 illustrates this. This helps to ensure that each preform pellet maintains a uniform distribution of the foaming agent throughout its volume, which in turn allows the foaming agent to contribute to the foaming of the bead rather than simply outgassing from the surface of the molten bead into the air. While the foamed glass beads can be formed without the sealant, in some cases the desired bead density is low and the desired number of bubbles / voids within each foamed glass bead is high, and this goal can be better achieved by incorporating the sealant. For example, without the sealant, the foaming agent and soluble flux may be more likely to migrate to the outside of the preform bead and will no longer be evenly distributed within the bead when it is heated. Therefore, in certain circumstances, it can be advantageous to incorporate a sealant.In some cases, if the sealant is included, it may partially or completely burn off during the heating of the beads.

[0046] In addition to incorporating the optional sealant into the flowable preform mix, a flux can be mixed into the flowable preform mix to create a final, pre-foamed bead paste. The consistency of this paste can range from a highly flowable liquid (i.e., a material that can be sprayed from a nozzle to form fine, sand-like beads) to a thick, dough-like paste (i.e., a material that can be used to form beads with diameters ranging from a few millimeters to several centimeters). The order in which the materials are introduced can be important. For example, some embodiments perform best after the flowable preform has been created if the sealant is introduced into the preform (i.e., dissolved and mixed in between the particles), followed by the introduction of the flux.This allows the sealant to graft the flux evenly throughout the entire bead during the drying and / or heating process. The flux may contain boron, which forms a borosilicate glass when the preformed pellets are heated. For example, the flux may be, but is not limited to, sodium borate, sodium tetraborate, disodium tetraborate, and combinations thereof. The flux may comprise between 0.01% and 0.3% (for example, 0.02% to 0.15%) by weight of the preformed pellet before heating / tempering.

[0047] As mentioned above, prior to heating / tempering, the flux, if present, can solidify the sealant in its dispersed composition to ensure that the preform pellet retains its components in their desired suspended configuration. During the initial heating stages (i.e., from 500-750 degrees Celsius), the flux can undergo a thermal transformation (i.e., it can melt) and create a seal around particles such as the crushed glass and foaming agent, effectively replacing the function of the binder by bonding the glass powder particles together. As in Fig. As illustrated in Figure 9, the flux can create a temporary wall between the glass powder particles, forming an airtight bubble. During the subsequent heating stages (i.e., from 650 to 1000 degrees Celsius), the glass powder particles soften further and adhere to one another along the boundaries created by the flux, as shown in Figure 9. Fig. Figure 10 illustrates this process. Therefore, when the preform pellets are heated, the binder burns off, the flux melts and bonds the glass powder particles together, the flux lowers the melting point of the glass, and as the glass melts, the flux helps to fuse the glass powder particles together until the glass forms a homogeneous skin / bubble. The foaming agent can then release gas and further inflate the molten beads.

[0048] The particle size and / or the amount of flux can determine the size and / or number of gas bubbles / inclusions within the final foamed glass beads. Therefore, to increase the number of cavities / nucleation sites within each foamed glass bead, more flux can be added to the preform pellets. The appropriate amount of a foaming agent can then inflate the cavities / nucleation sites to produce the desired density of the foamed glass bead. If no foaming agent is used, the desired density and number of bubbles can be achieved if the size of the flux particles corresponds to the size of the desired air inclusions and the correct amount of flux is used. Additionally, the flux can lower the melting point at which the glass powder forms a neck, and it can form an encapsulating bubble around the nucleation sites it creates.

[0049] As mentioned above, preform pellets can be produced prior to heating to form a final foamed glass bead. The preform pellets can be made from combinations of the glass powder, hydrated foaming agent, hydrated binder, optional sealant, flux, and solvent, which are mixed together to form the pre-foamed bead paste and then formed (i.e., pelletized) into pellets. In this disclosure, preform pellets simply refer to preform material that has been separated into individual structures prior to heating, such as pellets, beads, sprayed droplets, or any other shape. For example, preform pellets, as described in Fig. Figure 14 illustrates that the preform pellets can be bead-shaped (1420) or pellet-shaped (1440). After heating, the preform pellets typically assume a rounded shape, as shown by the heated bead (1410) and the heated pellet (1430) in Figure 14. Fig. 14 as well as the foamed glass bead 1510 in Fig. 15 illustrated.

[0050] In some embodiments, the preform pellets may also contain particles that have a higher melting point than glass and are wetted by the molten glass. The particles may be suspended in the molten pellets and may contribute to the structure of the final size of the bubbles / cavities in the foamed glass beads. In some cases, the particles may migrate to the vertices where the enclosed bubbles / cavities meet and may prevent the bubbles / cavities from coalescing. The particles may also modify the viscosity of the molten preform by impeding the flow of the molten glass. Finally, the higher melting point of the particles may increase the range of rates at which the beads can be heated and cooled without affecting the slower process by which surface energy forms rounded beads.

[0051] After the aforementioned materials (glass powder, foaming agent, binder, optional sealant, flux, solvent, and / or particles) have been mixed in, the preform pellets can be formed, for example, by using a mold or by depositing droplets of the desired size into a bed that may contain a bead carrier material. In some embodiments, additional bead carrier material can then be added to the preform pellets.

[0052] As mentioned above, these preformed pellets can be dried before heating / tempering. For example, in some embodiments, the preformed pellets can be air-dried after forming and before heating. The sealant, as described above, allows the solvent (e.g., water) to evaporate from the preformed pellets into the bead carrier material and the atmosphere, while retaining the solid and soluble components within the preformed pellets. While the sealant is described here as a critical component, it can be omitted if lower-strength beads are sufficient for an end user's purpose.

[0053] After drying (in some cases using heat), the bead paste may release dust, and the glass powder may be exposed, exhibiting sharp edges. Therefore, a solvent (for example, water) may be added back in. The solvent may be 0.5–25% (for example, 1%) by weight (or in some cases by volume) and may allow the bead paste to crumble uniformly without clumping, reduce the amount of dust, and, when mixed in, the process of incorporating the glass powder smoothly into the preformed pellets or beads. After the solvent has been added, the beads may then be heated as further described herein.

[0054] In some embodiments, the preform pellets can be distributed on a granular medium (for example, a non-wetting granular medium) and heated. The granular medium (in some cases a powder) can have a higher melting point than the melting point of the preform pellets, so that it retains its solid state and does not mix, blend, or sinter into the pellets. In some cases, the medium can also have a higher melting point than the highest temperature reached during the heating / tempering process. To the advantage of the foamed glass beads, the medium can impart a surface texture to the beads relative to the size of the medium and the contact points. Furthermore, in some cases, even if the medium is non-wetting with respect to the preform pellets, it can partially wet the glass and adhere permanently after cooling.This can be advantageous for the foamed glass beads because the medium adhering to the surface can impart a texture to the bead that increases the strength of the bond between the cement or other binder and the foamed glass beads. For example, the medium can be aluminum hydrate powder, quartz powder, or sand. If aluminum hydrate powder is used, the aluminum cations can migrate and modify the composition of the skin of the final foamed glass bead into an aluminoborosilicate glass, contributing to the overall compressive strength of the foamed glass bead.

[0055] After the preform pellets have dried and been distributed on or within the medium, they can be heated to a target temperature until the glass powder particles sinter together and the preform pellets become molten beads. The molten beads can then be cooled to produce the final foamed glass beads. Heating can require up to 15 minutes of ramp time (in some cases only 5 seconds for smaller beads (e.g., beads that have a diameter of 50 micrometers after heating) or only 5 minutes for larger beads (e.g., beads that have a diameter of 20 mm after heating)) and up to 15 minutes of residence time (in some cases only 5 seconds for smaller beads (e.g., beads that have a diameter of 50 micrometers after heating) or only 5 minutes for larger beads (e.g., beads that have a diameter of 20 mm after heating)).Beads which, after heating, have a diameter of 20 mm)) at a final temperature of the time and ranges between approximately 900 degrees Celsius ± 100 degrees (i.e. between 800 and 1000 degrees Celsius).

[0056] During heating, the preform pellets can undergo various chemical and phase transitions, including the decomposition of some of the subcomponents into gases and solids, the evaporation of volatile components, and the fluidization of some components. The gases can coalesce within the pellets to form inclusions / bubbles / cavities, and the size and distribution of these inclusions / bubbles / cavities can depend on the concentrations of the preform pellet paste components.

[0057] During the initial heating, water vapor may escape from the bead until the three-dimensional bead structure remains. Then, when the bead is heated to approximately 550 degrees Celsius, the flux becomes fluid and can wet the glass and foaming agent to create the preliminary cell structure, as shown in Fig. Figure 9 illustrates this. As mentioned above, the flux can be a borate compound. However, other fluxes (including sodium silicate) can be used as long as they maintain fluidization temperatures between 250 and 750 degrees Celsius so that they can adhere to the foaming agent and the glass powder particles, as shown in Figure 9. Fig. 10 illustrated.

[0058] As the preform pellets continue to heat, they reach a temperature at which the glass powder particles soften, and the foaming agent begins to generate gases through physical change and / or thermal decomposition. Therefore, heating allows the preform pellets to form beads, as the surface energy of the molten glass generally pulls the molten bead into a spherical shape. The gases generated by the changing / decomposing foaming agent can create uniformly distributed, fine gas bubbles / cavities within the glass matrix, as shown in Fig. Figure 11 illustrates this, and as the gases expand and the glass matrix becomes even more fluid, the bubbles can assume a more regular pattern, as shown in Figure 11. Fig. Figure 12 illustrates this. As the beads continue to heat up, the decomposed components (for example, the silicates from the bentonite, the aluminum and other metal ions from the bentonite, and the boron from the flux) can enhance the surface structure of the skin on the outside of the beads and the internal inclusions created by the gas cavities, as shown in Fig. 13 illustrated.

[0059] To maintain the spherical shape formed during heating, the preform pellets can be suspended in a granular medium that remains separate from them during annealing / heating and cooling (as mentioned above, for example, a non-wetting granular medium). This allows the foamed glass beads to be mechanically separated from the bead support material after heating / annealing is complete. In some cases, the foamed glass beads can be separated from the bead support material before cooling. The cooling phase allows the glass to stabilize through an annealing process.

[0060] As mentioned above, the bubbles / cavities formed during the heating and decomposition of the hydrated foaming agent can be gas bubbles and / or nucleation sites within the molten beads. The bubbles can have a diameter of less than 100 micrometers. Heating the flux during the annealing process can allow the glass powder to sinter and coalesce into continuous, molten glass beads, while trapping inclusions of ambient air and generating gas in the cavities created by the foaming agent, which are located between the molten glass powder particles.If heated for a sufficiently long time, the gas bubbles can eventually coalesce and escape the molten glass bead, or they can coalesce into larger bubbles, which are present in smaller numbers. This would result in an unfavorably dense glass bead, or, in the case of smaller bubbles, a weak bead. Therefore, rapid heating followed by rapid cooling, in the range of 5 seconds to 5 minutes heating and 5 seconds to 5 minutes holding time at the final temperature of the preforms, allows fine gas bubbles to be generated and trapped within the glass beads. The size and number of gas bubbles and the resulting cavities can be controlled by the size of the glass powder particles and the size of the preform pellets.Other factors that can control the size of the gas bubbles / voids include the annealing time, the temperature, the addition of non-melting particles, the properties of the fluxes and foaming agents, and the cooling rate. The longer the preform is annealed, the more time the gas bubbles have to coalesce and escape. Additionally, higher temperatures during annealing also facilitate the escape of gas bubbles through a less viscous molten glass.

[0061] In some cases, beads may develop a skin during or after annealing / heating due to the interaction of several layers / components. For example, an outer, non-porous skin may result from the incorporation of the glass powder with the flux during heating. Alternatively, the silicon dioxide in the glass and the bead support medium (e.g., aluminum hydrate powder) may contribute to the skin on the bead. In another example, if the outer bubbles burst during heating, the components surrounding these bubbles may remain on the surface and thicken to form the skin.

[0062] Alternatively, after being heated for a predetermined time, the foamed glass beads can be removed and cooled. Once cooled for a predetermined time or to a predetermined temperature, a coating can be applied to the final foamed glass beads. The coating can be a sealant or a primer. For example, gas bubbles near the surface of the molten bead can burst and condense on the outside of the bead, forming a skin. A skin can also be formed and / or thickened by rolling the still-molten glass beads down an inclined screen surface after annealing. The process of rolling down the screen surface can compress the outer skin of the beads, forming a shell. A stronger, spherical shell can be resistant to isostatic pressure.

[0063] The final foamed glass beads can withstand at least 1,000 psi (for example, 2,000 psi) and in some cases up to 70,000 psi. The final beads can be round, which allows for ideal mixing into concrete or thermoplastics. The concrete / thermoplastic mix can flow more easily around the beads, and the beads can occupy a larger volume fraction than would be the case if they were irregularly shaped and had flat sides or sharp edges. Irregularly shaped beads do not roll or slide against each other well and do not pack tightly. Round beads flow well and pack tightly, so less cement / thermoplastic material is required, and the overall strength of the cured product is higher. In some embodiments, the foamed glass beads (aggregate) can comprise up to 85% of the final, finished concrete mix by volume.In embodiments where the beads are used in thermoplastics, the foamed glass beads can comprise approximately 40%-60% of the final aggregate mixture by weight (15-20% by volume), which is similar to current fillers for thermoplastics, or up to 80% of the final aggregate mixture by volume.

[0064] In one aspect, the disclosure provides foamed glass beads formed from glass, a hydrated foaming agent, a hydrated binder that holds the glass and the hydrated foaming agent in solution, a flux, and a solvent. The glass may be derived from cullet ground into glass powder. The glass powder, the hydrated foaming agent, the hydrated binder, the flux, and the solvent may be mixed together to create a preform material, which is pelletized to produce preform pellets. The preform pellets may be held together by the hydrated binder. In some cases, the foamed glass beads may also contain a sealant. In these cases, the sealant may be mixed with the glass powder, the hydrated foaming agent, the hydrated binder, the flux, and the solvent to produce the preform material.The sealant, if present, can create a barrier throughout the preform pellets to limit the migration of soluble and insoluble components, while allowing the solvent and solvent vapor to escape. The flux can lower the melting temperature of the glass powder, create a seal around the glass powder and the hydrated foaming agent, and help the glass powders fuse together after fusion. The hydrated binder and sealant, if present, can burn off during the heating process. During the heating process, the flux and the hydrated foaming agent can be incorporated into the glass powder. The preform pellets can be dried and then heated to a predetermined temperature. The heating process produces the final foamed glass beads.

[0065] In some cases, additional modifications or steps can be added to the basic technology. For example, the foamed glass beads may further comprise an outer, non-porous skin layer on the final foamed glass beads, derived from the incorporation of the glass powder into the flux. In another example, the interior of the foamed glass beads may be characterized by cavities surrounded by walls of a solid matrix. In yet another example, the hydrated foaming agent may decompose during heating, thereby generating gas bubbles within the glass matrix. The solvent may be water. The hydrated foaming agent may be bentonite.In yet another example, there may be a multitude of sealed air inclusions resulting from the incorporation of the glass powder into the flux. The hydrated foaming agent may cause gas production during annealing, and this gas may migrate to the numerous sealed air inclusions, expanding them into bubbles within the preformed pellets. The foamed glass beads may exhibit uniformly distributed bubbles upon cooling. The flux may contain boron and can be selected from the group consisting of sodium borate, sodium tetraborate, disodium tetraborate, and combinations thereof. The sealant may be an adhesive compound and may include polyvinyl acetate, ethanol, water, and acetate. The sealant may be an alginate gel and can be produced by mixing solutions of sodium alginate and calcium chloride.In another example, the preform pellets can be suspended in a granular medium that remains separate from the preform pellets during tempering. In yet another example, the hydrated binder can comprise a sugar that chars during heating. Furthermore, the sugar can be selected from the group consisting of xanthan gum, guar gum, and combinations thereof. In yet another example, before tempering the preform pellets, the glass content can be between 93.3% and 99.6% (e.g., 96.5% to 99.2%) by weight, the hydrated foaming agent before hydration can be between 0.31% and 4.67% (e.g., 0.6% and 2.4%) by weight, the hydrated binder before hydration can be between 0.062% and 1.17% (e.g., 0.12% and 0.6%) by weight, the sealant between 0% and 0.56% (e.g., 0% and 0.29%) by weight, and the flux can be between 0.01% and 0.3% (e.g.,The solvent concentration can be between 0.02% and 0.15% by weight. Before drying, the solvent concentration can be between 20.0% and 50.0% (e.g., 30.0% to 37.6%) by weight.

[0066] In another aspect, the disclosure provides a method for producing foamed glass beads, wherein the method comprises hydrating a foaming agent, hydrating a binder, mixing a glass powder with the hydrated foaming agent and the hydrated binder to produce a premix, wherein the glass powder may have a predetermined mesh size, adding a solvent to the premix and mixing to produce a flowable preform mixture, mixing a flux into the flowable preform mixture to produce a pre-foamed bead paste, pelletizing the pre-foamed bead paste to produce preform pellets / beads, heating the preform pellets / beads until particles of the glass powder from the preform pellets / beads sinter together and the preform pellets / beads become molten beads, and removing the molten beads from the heat.to cool them into foamed glass beads. In some embodiments, the method may further include the step of mixing a sealant into the flowable preforming mixture (for example, after mixing the solvent to produce a flowable preforming mixture), whereby the sealant can dissolve and mix with the particles.

[0067] In some cases, additional modifications or steps can be added to the basic technology. For example, the process can further include drying the preformed pellets / beads before heating. In another example, the process can further include suspending the preformed pellets / beads on a bed of bead support material with a higher melting point than that of the preformed pellets / beads and adding additional bead support material to the pre-expanded pellets / beads, where the bead support material can be aluminum hydrate powder. The molten beads can be separated from the bead support material by mechanical means. In yet another example, the hydrated foaming agent can decompose during heating and create nucleation sites for gas within the molten beads.Furthermore, the hydrated foaming agent can be bentonite clay, which releases gas upon heating. This gas can migrate from the bentonite clay to the nucleation sites, creating gas bubbles within the molten pellets. The flux can contain boron. In yet another example, the binder can be xanthan gum. The preformed beads can be heated to between 800 and 1000 degrees Celsius. EXECUTION FORM 2

[0068] In some embodiments, the additive comprising the foamed glass beads may contain a void agent that can be ground into a fine powder before being combined with the glass, water, and / or a binder. The void agent can cause uniformly distributed voids or gas inclusions / bubbles to form within the preform pellet during annealing, thereby reducing the lighter weight of the glass beads without compromising their strength (as might be the case with hollow glass beads). In some embodiments, the void agent creates these gas inclusions by evaporating and leaving behind voids. These voids can act as nucleation sites within each molten preform pellet, providing a location to which carbon dioxide or other gas bubbles generated during the annealing process can migrate or escape, rather than escaping from the bead.Therefore, the void representative is effectively a seed particle that creates small nucleation sites during the tempering of the preform pellet, and the nucleation sites are air inclusions or bubbles within each glass bead. In other embodiments, the void representative can simply be the air inclusion to which gas from the foaming agent migrates and expands.

[0069] The cavity representative can be produced by combining a foaming agent and a flux and drying the mixture. Alternatively, the cavity representative can simply comprise particles such as wood particles, flour, and cornstarch. The cavity representative may be insoluble in water and evaporate during the tempering process when temperatures reach approximately 600°C or higher. In cases where the cavity representative is produced by combining a foaming agent and a flux, which is subsequently dried, the dried cavity representative can be ground into a powder of a predetermined size (or predetermined sizes). For example, in some embodiments, lithium carbonate (the foaming agent) and sodium silicate (the flux) can be added together to produce lithium powder.The lithium powder can then be ground and / or added to water to create the void representative. The size(s) and / or quantity(ies) of the void representative powder particles can determine the size and / or number of gas bubbles / inclusions within the final foamed glass beads. Therefore, to increase the number of voids / nucleation sites within each foamed glass bead, more void representative particles can be added to the preform pellets. The appropriate amount of a foaming agent can then inflate the voids / nucleation sites to produce the desired density of the foamed glass bead. If no foaming agent is used, the desired density and number of bubbles can be achieved if the size of the void representative particles is the same as the desired air inclusions and the correct amount of void representative is used.In some cases, the ratio of foamed glass bead to cavity representative is approximately a volume ratio of 125:1 or a diameter ratio of 5:1.

[0070] The foaming agent for the cavity representative can be a powdered carbonate such as lithium carbonate. Optionally, the foaming agent can be calcium carbonate. During heating / tempering, the foaming agent can cause the production of carbon dioxide, and this carbon dioxide can migrate to the gas inclusions (i.e., cavities / nucleation sites) to create gaseous bubbles within the molten pellets. Therefore, the foamed glass beads may exhibit uniformly distributed bubbles after cooling.

[0071] The flux for the cavity representative can be a co-alkali activator such as sodium silicate. The flux can lower the melting point at which the glass powder forms a neck and can create an encapsulating bubble around the nucleation sites generated by the cavity representative. Additionally, adding the flux to the foaming agent used to generate the cavity representative can prevent the foaming agent and / or the flux from migrating to the periphery of the preform pellets during air drying prior to annealing. This helps each preform pellet maintain a uniform distribution of the foaming agent throughout its volume, which in turn allows the foaming agent to contribute to bead foaming rather than simply outgassing from the surface of the molten bead into the air.Only with a foaming agent instead of a complete cavity representative can the foaming agent migrate to the outside of the preformed bead and no longer be evenly distributed within the bead during annealing. Therefore, the desired low bead density and high number of bubbles within each foamed glass bead can be achieved by using the appropriate combination of flux and foaming agent.

[0072] However, in some cases, a bead with a desired density can be produced using only a foaming agent (i.e., no flux is added to the foaming agent). In this case, the gas bubbles may be randomly large and generally larger compared to when a flux is used with the foaming agent. This is because most of the gas escapes from the foaming agent during annealing and therefore does not contribute to reducing the overall density of the foamed glass bead. One way to address this concern is to microencapsulate the foaming agent. For example, a mixture of acrylic lacquer and a foaming agent can be sprayed into the air to allow the droplets time to dry before settling, creating microbeads of foaming agent that are insoluble in water.These microbeads can distribute the nucleation sites in the preform pellets more evenly and control the final size of the bubbles in the foamed glass beads.

[0073] In addition to glass powder, the cavity representative, and water, the glass aggregate may contain a binder. In some embodiments, the binder may be sodium silicate or clay, such as bentonite. Bentonite clay can produce a thick, viscous emulsion that suspends and separates the glass powder particles, thereby creating a homogeneous, free-flowing mixture ideal for metering or forming preforms. In other embodiments, the binder may be sodium silicate. In cases where sodium silicate is used as a flux in the cavity representative, the sodium silicate used for the cavity representative is first added to the foaming agent before additional sodium silicate is added to the aggregate for use as a binder. The binder may burn off completely during annealing, or it may be incorporated into the molten preform.As mentioned above, the binder may comprise less than approximately 1% of the preform pellets by weight before heating / tempering.

[0074] As mentioned above, preform pellets are produced prior to annealing to form a final foamed glass bead. These preform pellets can be made by combining the glass powder, void agent, water, and binder, mixing them together, and then forming them into pellets. In some embodiments, the preform pellets may also contain particles with a higher melting point than glass, which are wetted by the molten glass (for example, aluminum oxide or quartz). The particles may be suspended in the molten pellets and contribute to the structure and final size of the bubbles in the foamed glass beads. In some cases, the particles may migrate to the vertices where the trapped bubbles meet and prevent the bubbles from coalescing together.The particles can also alter the viscosity of the molten preform by impeding the flow of the molten glass. Finally, the higher melting point of the particles can increase the range of rates at which the beads can be heated and cooled without affecting the slower process by which surface energy forms rounded beads.

[0075] After the aforementioned materials (glass powder, void filler, water, binder, and / or particles) have been mixed, the preform pellets can be formed. These preform pellets can be dried before heating / tempering. For example, in some embodiments, the preform pellets can be air-dried after they have been formed and before they are heated.

[0076] After drying (in some cases using heat), the bead paste may release dust, and the glass powder may be exposed, exhibiting sharp edges. Therefore, a solvent (for example, water) can be added back in. The solvent can be 0.5–25% (for example, 1%) by weight (or in some cases by volume) and can allow the bead paste to crumble uniformly without clumping, reduce the amount of dust, and, when mixed in, the mixing process can cause the glass powder to be smoothly rolled into the preformed pellets or beads.

[0077] In some embodiments, the preformed pellets can be distributed on a granular, non-wetting medium and heated. The granular, non-wetting medium (in some cases a powder) can have a higher melting point than the melting point of the preformed pellets, so that it retains its solid state and does not mix, merge, or sinter to the pellets. In some cases, the non-wetting medium can also have a higher melting point than the highest temperature reached during the tempering process. To the advantage of the foamed glass beads, the non-wetting medium can impart a surface texture to the beads relative to the size of the medium and the contact points. Furthermore, in some cases, the non-wetting medium can partially wet the glass and adhere permanently after cooling.This can be advantageous for the foamed glass beads, as the medium adhering to the surface can impart a texture to the bead that increases the strength of the bond between the cement and the foamed glass beads. For example, the non-wetting medium could be aluminum hydrate powder.

[0078] After the preform pellets have been dried and spread on the non-wetting medium, they are rapidly annealed to produce the final foamed glass beads. Annealing requires heating at increasing temperatures for 5 seconds to 15 minutes (only 5 seconds for a small bead and only 5 minutes for a larger bead, as described above in embodiment 1), followed by a dwell time of 5 seconds to 15 minutes at the final temperature (only 5 seconds for a small bead and only 5 minutes for a larger bead, as described above in embodiment 1), and takes place at approximately 900 degrees Celsius ± 100 degrees. During annealing, the preform pellets can form near-spherical shapes because the surface energy of the molten glass generally pulls the molten bead into a spherical form. Additionally, uniformly distributed, fine gas bubbles can form within each molten preform pellet.To maintain the spherical shape formed during heating, the preform pellets can be suspended in a non-wetting granular medium that remains separate from the preform pellets during tempering and cooling.

[0079] As mentioned above, the bubbles formed during heating can be carbon dioxide bubbles. These can have a diameter of less than 100 micrometers. Heating and outgassing of the foaming agent during the tempering process can allow the glass powder to sinter and coalesce into continuous, molten glass beads, while trapping ambient air inclusions and generating gas in the cavities created by the void agent, which are located between the molten glass powder particles. If heated for a sufficiently long time, the gas bubbles can eventually coalesce and escape from the molten glass bead, resulting in an unfavorably dense glass bead.Therefore, rapid heating followed by rapid cooling, typically within 5 seconds to 5 minutes of heating and 5 seconds to 5 minutes of holding time at the final temperature of the preforms, allows for the generation of fine gas bubbles, which are then trapped within the glass beads. The size and number of these gas bubbles can be controlled by the size of the glass powder particles and the size of the preform pellets. Other factors influencing the size of the gas bubbles include the annealing time, the temperature, the addition of non-melting particles, the properties of the foaming agent, and the cooling rate. The longer the preform is annealed, the more time the gas bubbles have to coalesce (becoming fewer and larger) and / or escape. Additionally, higher temperatures during annealing facilitate the escape of gas bubbles through a less viscous molten glass.

[0080] After the foamed glass beads have been heated for a predetermined time, they can be removed and cooled. Once cooled, either for a predetermined time or to a predetermined temperature, a coating can be applied to the final foamed glass beads. The coating can be a sealant or a primer. In some cases, the beads may develop a skin during or after annealing. For example, gas bubbles near the surface of the molten bead may burst and condense on the outside of the bead, creating a skin. A skin can also form and / or be thickened by rolling the still-molten glass beads down an inclined screen or surface after annealing. The rolling process can compress the outer skin of the beads, creating a shell.A stronger, spherical shell can be resistant to isostatic pressure.

[0081] The final foamed glass beads can withstand at least 1,000 psi (for example, 2,000 psi) and in some cases up to 70,000 psi. The final beads can be round, which allows for ideal mixing with concrete or other applications where flowability is desired, such as compounding thermoplastics or sanitation for fracking. The concrete / thermoplastic mixture can flow more easily around the beads, and the beads can occupy a larger volume fraction than would be the case if they were irregularly shaped and had flat sides or sharp edges. Irregularly shaped beads do not roll or slide against each other well and do not pack tightly. Round beads flow well and pack tightly, so less cement, thermoplastic, or binder is needed, and the overall strength of the cured product is higher.In some embodiments, the foamed glass beads (aggregate) can comprise up to 85% of the final, finished concrete mix by volume. In embodiments where the beads are used in thermoplastics, the foamed glass beads can comprise approximately 40%–60% of the final aggregate mix by weight (15–20% by volume), which is similar to current fillers for thermoplastics, or up to 80% of the final aggregate mix by volume.

[0082] In one aspect, the disclosure provides foamed glass beads formed from glass, a cavity representative comprising a foaming agent and a flux, water, and a binder. The glass may be derived from cullet ground into glass powder; the foaming agent and flux may be added together and dried to produce the cavity representative; the glass powder, cavity representative, water, and binder may be mixed together to produce a preform material, which is pelletized to produce preform pellets; and the preform pellets may be annealed to produce the final foamed glass beads.

[0083] In some cases, additional modifications or steps can be added to the basic technology. For example, the foamed glass beads can further include a coating on the final foamed glass beads, and the coating can be applied after the preform pellets have been annealed. In another example, the voiding agent can be ground into a fine powder before being combined with the glass, water, or binder. In yet another example, the voiding agent can be insoluble in water. In still another example, the voiding agent can cause uniformly distributed gas inclusions to form in the preform pellet during annealing by evaporating and leaving the gas inclusions behind. The foaming agent can be lithium carbonate.In another example, the foaming agent can cause the production of carbon dioxide during annealing, and the carbon dioxide can migrate to the gas inclusions to create bubbles in the preform pellets. Furthermore, the foamed glass beads can exhibit uniformly distributed bubbles after cooling. In yet another example, the flux can be sodium silicate. In still another example, prior to annealing the preform pellets, the void representative can be between 0.25% and 1.00% by weight, the water can be between 30% and 50% by weight, and the binder can be less than 1% by weight. In yet another example, the preform pellets can be suspended in a granular, non-wetting medium that remains separate from the preform pellets during annealing. In yet another example, the preform pellets can form spheres upon heating during annealing.

[0084] In another aspect, the disclosure provides a method for producing foamed glass beads, wherein the method comprises adding a foaming agent to a flux to produce a cavity representative; drying the cavity representative; grinding the cavity representative into a powder; adding water to the powdered cavity representative and mixing to produce a primary preform mixture; mixing the glass powder into the primary preform mixture to produce a secondary preform mixture; mixing a binder into the secondary preform mixture to produce a final preform mixture; pelletizing the final preform mixture to produce preform pellets; and heating the preform pellets until particles of the glass powder from the preform pellets sinter together and the preform pellets become molten beads.and includes removing the molten beads from the heat to cool them into foamed glass beads.

[0085] In some cases, further steps or clarifications of the composition may be necessary. For example, the process may include the additional step of drying the preform pellets before heating. In another example, the preform pellets may be heated on or within a non-wetting granular medium, and the non-wetting granular medium may have a higher melting point than the preform pellets. In yet another example, the voiding agent may evaporate during heating, creating nucleation sites within the molten pellets. Furthermore, the foaming agent may be lithium carbonate, which releases carbon dioxide upon heating. The carbon dioxide from the lithium carbonate may migrate to the nucleation sites to create gas bubbles within the molten pellets. The flux may be sodium silicate. In some cases, the binder may also be sodium silicate.In another example, the process can include the additional step of adding a coating to the foamed glass beads. In some cases, the void representative can be between 0.25% and 1.00% by weight, the water can be between 30% and 50% by weight, and the binder can be less than 1.00% by weight.

[0086] Persons skilled in the art with ordinary knowledge in fields relevant to this disclosure and the subject matter discussed herein will recognize that embodiments may include fewer features than illustrated in a single embodiment described by way of example or otherwise considered herein. The embodiments described herein are not intended to be an exhaustive representation of the ways in which different features may be combined and / or arranged. Accordingly, the embodiments do not represent mutually exclusive combinations of features; rather, embodiments may include a combination of different individual features selected from different individual embodiments, as would be understood by persons with ordinary knowledge in the relevant fields.Furthermore, elements described in relation to one embodiment may be implemented in other embodiments, even if they are not described in such embodiments, unless otherwise specified. Although a dependent claim may refer to a specific combination with one or more other claims, other embodiments may also include a combination of the dependent claim with the subject matter of any other dependent claim or a combination of one or more features with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a particular combination is not intended.Furthermore, it is intended to include features of one claim in any other independent claim, even if that claim is not directly dependent on the independent claim.

[0087] Any foregoing incorporation by reference to documents is limited such that no subject matter is included which contradicts the express disclosure herein. Any foregoing incorporation by reference to documents is further limited such that no claims contained in the documents are incorporated herein by reference. Any foregoing incorporation by reference to documents is further limited such that definitions provided in the documents are not incorporated herein by reference unless expressly included herein.

Claims

[1] Foamed glass beads, including: heated preform pellets, wherein the preform pellets comprise a pelletized pre-foamed bead paste comprising a glass powder that has a predetermined mesh size, a hydrated foaming agent, a hydrated binder, a flux and a solvent; where the combined flux and glass powder have a lower melting point than the melting point of the glass powder alone, The flux forms a seal around particles of the glass powder and the hydrated foaming agent. the flux has a lower melting point than glass and The hydrated binder has a thermal decomposition temperature of 450 degrees Celsius or below. [2] Foamed glass beads according to claim 1, further comprising an outer non-porous skin layer on the foamed glass beads, comprising the glass powder and decomposed components of the flux. [3] Foamed glass beads according to claim 1, wherein the hydrated foaming agent has a thermal decomposition temperature between 600 Celsius and 950 Celsius. [4] Foamed glass beads according to claim 1, wherein a large number of sealed air inclusions are present, which are derived from the introduction of the glass powder into the flux, the hydrated foaming agent enables the production of gas during tempering and the gas can migrate to the multitude of sealed air inclusions, enlarging them into bubbles in the preformed pellets. [5] Foamed glass beads according to claim 1, wherein the heated preform pellets also include a sealant, The sealant and the flux are cross-linked polymers. the cross-linked polymers are configured to immobilize soluble and insoluble components, and The sealant has a thermal decomposition temperature of 450 degrees Celsius or below. [6] Foamed glass beads according to claim 5, wherein the cross-linked bonds are hydrogen bonds. [7] Foamed glass beads according to claim 5, wherein the sealant is an adhesive compound and the adhesive compound comprises polyvinyl acetate, ethanol, water and acetate. [8] Foamed glass beads according to claim 5, wherein the sealant is an alginate gel. [9] Foamed glass beads according to claim 8, wherein the alginate gel comprises sodium alginate and calcium chloride. [10] Foamed glass beads according to claim 1, wherein interiors of each of the foamed glass beads are characterized by cavities surrounded by walls of a solid matrix. [11] Foamed glass beads according to claim 1, wherein the solvent is water. [12] Foamed glass beads according to claim 1, wherein the hydrated foaming agent is bentonite. [13] Foamed glass beads according to claim 1, wherein the flux comprises boron and is selected from the group consisting of sodium borate, sodium tetraborate, disodium tetraborate and combinations thereof. [14] Foamed glass beads according to claim 1, wherein the hydrated binder comprises a sugar which burns off during heating and the sugar is selected from the group consisting of xanthan gum, guar gum and combinations thereof. [15] Foamed glass beads according to claim 1 in combination with a plastic product, wherein the foamed glass beads are uniformly distributed in the plastic product, and wherein the foamed glass beads comprise 15-80% of the combined product by volume.

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