Method for increasing recycling of waste glass

Abstract

Disclosed herein are methods of reusing at least a portion of waste glass produced in a foam glass manufacturing process by returning the waste glass back into the foam glass manufacturing process. The method includes altering the overall glass composition, allowing for higher oxidant content, which in turn allows for inclusion of more waste material during the production of glass melts and foam glass. In particular, the glass composition in the melt is treated to increase the amount of oxidant (e.g., MnO2) above those used in conventional manufacturing processes while also maintaining the important physical properties of the final foam glass product.

Description

[0001] Cross - reference

[0002] This application claims priority and the benefit of U.S. Provisional Patent Application No. 63 / 385,276, filed on November 29, 2022, the content of which is incorporated herein by reference. Technical Field

[0003] The inventive concept described in the present disclosure relates to foam glass and, more particularly, to methods for reducing unnecessary waste associated with conventional foam glass production processes. Background Art

[0004] Foam glass is a solid foamed product formed by expanding gas in a molten glass matrix. Foam glass is a special class of lightweight glass materials that have many small pores entrapped within a rigid matrix. Common techniques for manufacturing foam glass include the following steps: 1) melting glass raw materials at a high temperature to form glass, 2) grinding the glass into powder while introducing a foaming agent, 3) heating the ground glass raw materials, and 4) foaming the ground glass powder at a high temperature. The gas generated during the foaming stage forms pores within the glass matrix, similar to traditional foams. Due to the unique combination of the thermal insulation ability, mechanical strength, chemical stability, and fire resistance of foam glass, products based thereon can be used in various industries (see ASTM C552 for foam glass thermal insulation classification). In particular, closed - cell foam glass is formed by trapping gas within the pores and has improved thermal insulation ability and a stable thermal conductivity compared to foam glass with open pores. Additionally, foam glass with closed pores is vapor - impermeable, which is a critical factor in many applications.

[0005] Foam glass has a relatively high thermal insulation ability, making it a preferred thermal insulation material for certain applications, especially those where other unique properties of foam glass (such as its high compressive strength) can be utilized. However, due to its rigid structure, a large amount of waste material is often generated during the manufacturing process (e.g., due to cutting foam glass blocks to meet manufacturing specifications). Additionally, the waste material includes an undesirable amount of carbon, making the reuse of the waste too expensive or infeasible.

[0006] Previous attempts to produce foam glass products using waste glass materials have generally resulted in poor - quality foamed materials (e.g., open pores, reduced thermal insulation ability). The reduction in the desired foam glass quality may be due to the addition of oxidants, such as MnO2, to the grinding step. Therefore, there is still a need for an effective method and composition for reusing waste glass materials in foam glass manufacturing. Summary of the Invention

[0007] The present disclosure relates to methods and compositions for modifying and reusing / recycling waste glass materials generated during the manufacture of foam glass. The advantages of foam glass modification / recycling are that it allows for the reintroduction of waste materials into a glass melter (hereinafter referred to as a "melter") in greater amounts than previously possible; thus potentially reducing the environmental impact of waste foam glass materials and the cost of foam glass production. The overall inventive concept is based in part on the discovery that by introducing waste materials (either alone or in combination with raw materials) and an oxygen source into the melter, greater amounts of waste materials can be used to produce foam glass products while maintaining desired properties such as hydrolysis resistance, e-modulus, chemical durability, closed cell content, thermal conductivity, and mechanical strength, as well as other desired foam glass properties.

[0008] Various exemplary embodiments of the inventive concept relate to foam glass products made from a glass composition comprising MnO in an amount of 2 wt% to 10 wt% and at least one of the following: SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; and BaO + SrO in an amount of 0 wt% to 0.3 wt%. In certain exemplary embodiments, the foam glass product satisfies at least one of the following: is a closed cell foam; has a density of about 75 kg / m 3 to 300 kg / m 3 ; has a thermal conductivity of 0.033 W / mK to 0.06 W / mK; and has a compressive strength of 0.4 MPa to 2.4 MPa. In certain exemplary embodiments, the glass composition comprises MnO in an amount of 2 wt% to 10 wt%, SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; SO3 in an amount of 0.2 wt% to 0.9 wt%; Fe2O3 in an amount of 1 wt% to 6 wt%; BaO + SrO in an amount of 0 wt% to 0.3 wt%; and TiO2 in an amount of 0 wt% to 0.5 wt%.

[0009] Various exemplary embodiments of the inventive concept relate to a foam glass product made of a glass composition comprising a combination of MnO in an amount of 0.4 wt% to 10 wt% and at least one of BaO, SrO, and combinations thereof in an amount of 0.3 wt% to 2 wt%, and at least one of the following: SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; and Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%. In certain exemplary embodiments, the foam glass product satisfies at least one of the following: is a closed-cell foam; has a density of about 75 kg / m 3 to 300 kg / m 3 ; has a thermal conductivity of 0.033 W / mK to 0.06 W / mK; and has a compressive strength of 0.4 MPa to 2.4 MPa. In certain exemplary embodiments, the glass composition comprises a combination of MnO in an amount of 0.4 wt% to 10 wt% and BaO and SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; SO3 in an amount of 0.2 wt% to 0.9 wt%; Fe2O3 in an amount of 1 wt% to 6 wt%; BaO + SrO in an amount of 0.3 wt% to 2.0 wt%; and TiO2 in an amount of 0 wt% to 0.5 wt%.

[0010] Various exemplary embodiments disclose a method for producing a foam glass product comprising at least a portion of waste material or recycled cullet. The method includes providing a source of raw materials in a melter, wherein the raw materials include two or more of virgin materials, waste materials, and recycled cullet; providing a source of oxidizer to the melter and mixing the oxidizer with the raw materials to form a glass melt, wherein the oxidizer is included in an amount to achieve a predetermined level of the oxidizer in the glass melt; cooling the glass melt; and subjecting the resulting glass material to a foam glass production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The general inventive concept will be described in more detail with reference to the accompanying drawings, in which:

[0012] Figure 1 A laboratory-scale porous foam sample made using a foam glass mixture according to the general inventive concept is shown.

[0013] Figure 2 A laboratory-scale foam sample made using a conventional glass designed for pore formation, which contains ≤2 wt% MnO2, is shown.

[0014] Figure 3 Shows a laboratory-scale porous foam sample made using a foam glass mixture and an elevated amount of oxidizer according to the general inventive concept.

[0015] Figure 4 Is a graph showing the relationship between the thermal conductivity and the foam density of a conventional foam glass product and a foam glass product produced according to the general inventive concept.

[0016] Figure 5 Is a graph showing the relationship between the compressive strength and the foam density of a conventional foam glass product and a foam glass product produced according to the general inventive concept.

[0017] Figure 6 Is a graph showing the relationship between the E-modulus and the foam density of a conventional foam glass product and a foam glass product produced according to the general inventive concept.

[0018] Figure 7 Shows an image of a portion of a foam sample having open pores, which is made by incorporating additional oxides into a ball mill (i.e., solid-state mixing) during production.

[0019] Figure 8 Shows an image of a portion of a foam sample having closed pores, which is made by incorporating additional oxides into the foam manufacturing process according to the general inventive concept. Detailed Description

[0020] Although various exemplary compositions, materials, and methods are described herein, other compositions, materials, and methods similar or equivalent to those described herein are also encompassed by the general concept of the present disclosure. Although the general concept admits many different forms of embodiments, at least one specific embodiment of such concepts is described in detail herein, and it should be understood that the present disclosure should be considered an example of the principles of the general inventive concept.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of the present disclosure belongs.

[0022] As used herein, the term "raw material" refers to the starting materials used to melt glass suitable for foaming during the foam glass production process, and may include both virgin materials and recycled and scrap materials. "Virgin" materials refer to materials that are typically produced by mining or chemical synthesis and are not recycled, reused, or repurposed from other products or processes.

[0023] As used herein, the term "scrap material" refers to recycled, reused, waste, and / or cullet materials generated from the glass manufacturing process or from foam glass products. The glass composition of the scrap material typically contains higher levels of undesirable reducing oxides and carbon contamination than virgin materials.

[0024] As used herein, the term "recycled cullet" refers to post-consumer recycled glass that is not generated from foam glass products, such as post-consumer float glass or container glass. Such recycled cullet typically contains undesirable organic contamination.

[0025] As used herein, the term "foamable glass material" refers to any glass material that is foamable and is formed by combining virgin materials, scrap materials, recycled cullet, and other materials (e.g., oxidizing agents) in a melter to form a glass melt having a desired composition.

[0026] As used herein, the term "glass melt" refers to a melt produced from homogenized raw materials, typically by dissolving constituent oxides at high temperature (e.g., in a melter).

[0027] As used herein, the term "foam glass product" refers to a material produced by subjecting a foamable glass material to a pore-forming process (e.g., sintering, foaming, annealing, etc.). The product can then undergo additional processing or finishing (e.g., cutting). Typically, foam glass products according to the overall inventive concept are foam glass insulation according to ASTM C552 and / or EN 13167.

[0028] As used herein, the terms "weight percent," "wt. %," "wt%," and "percent by weight" are used interchangeably and are intended to represent, unless otherwise specified, the weight percentage (or percent by weight) based on the weight of the total composition.

[0029] Foam glass is a rigid, non-porous insulation material. Foam glass is typically durable, chemically resistant, fireproof, airtight, and has a high strength-to-weight ratio, making it an ideal insulator for various demanding conditions and / or when mechanical strength is also an important property.

[0030] Foam glass can be manufactured by many methods, using compositions based on various glass raw materials and foaming agents. Conventional processes for forming foam glass products typically include grinding glass materials with a foaming agent and an optional oxidizing agent (each in the solid phase) in a ball mill to mix the materials and reduce the particle size of the materials. However, since the starting materials are mixed in the solid phase, this method does not ensure a high level of distribution homogeneity throughout the mixture.

[0031] According to the inventive concept, instead of mixing the starting raw materials in the solid phase (as done in conventional processes, resulting in foam products with undesired open-cell characteristics), the raw materials are optionally ground and then added to a melter and mixed in the melter to produce a glass melt. The materials melted to produce the glass melt may include raw materials, virgin materials, waste materials, recycled cullet, or mixtures thereof. One or more oxidizing agents (e.g., MnO2) are introduced directly into the melter and uniformly combined with the raw materials to form the glass melt. The glass melt is then cooled, and the resulting foamable glass material is stored for later use or sent to the next step of the process.

[0032] The next step includes grinding the cooled glass into small particles while introducing a foaming agent (e.g., a carbon source). The grinding reduces the size of the glass particles, coats the glass particles with foaming agent particles, and forms a ground glass batch.

[0033] After grinding, the ground glass batch with the foaming agent is sintered, whereby the glass particles soften and flow together into a viscous glass matrix, and the foaming agent particles are embedded therein. When the foaming agent is embedded in the glass matrix, any free or reactive oxygen in the glass (e.g., bound to transition metals) reacts with the carbon to form CO2, which will nucleate and form bubbles near the carbon particles.

[0034] Thus, generally, the production of foam glass insulation involves the reaction of oxygen-rich glass with carbon to generate CO2 gas that fills the pores of the foam glass. While the glass melt needs to be highly oxidized, the resulting foam glass is in a reduced state (most of the oxidizing elements in the melter glass will be in a reduced state in any resulting waste) and contains carbon.

[0035] This reduced state generally limits the amount of waste material (or recycled cullet) that can be recycled (e.g., by direct combination with raw materials to be re-introduced into the melting process), because adding waste material that is in a reduced state relative to the state required for effective pore formation (i.e., it has low foaming ability) to the raw materials / virgin materials has the effect of reducing the overall oxidation state of the glass melt and impairing the downstream pore formation process. Similarly, organic contaminants in recycled cullet will also reduce the overall oxidation state of the glass batch, likewise impairing the downstream pore formation process. A previous method of addressing this problem was to add an oxidizing agent to the ground glass batch (i.e., in the solid phase after the melter), but this method has limitations. For example, attempts to add an oxygen source during the grinding stage have been shown to impair the desired properties of the final product (e.g., open cells in the foam glass, reduced insulation ability, etc.).

[0036] Accordingly, the overall inventive concept is based in part on the discovery that during the melting stage, the oxidation state of the foamable glass material can be increased / improved by introducing an oxygen source / oxidizing agent source directly into the melter. By introducing an oxygen source (such as MnO2) during this process stage, waste materials and / or recycled cullet can be used at higher concentrations in the foam glass forming process while still maintaining the desired properties of the foamable glass material to produce a foam glass insulation product having the desired properties (such as closed cell content, thermal insulation ability, mechanical strength).

[0037] An important consideration in reintroducing recycled cullet or waste materials into the foam glass production process is how much additional oxidizing agent can be added to the materials in the melter without compromising the important properties of the foam glass product.

[0038] While not wishing to be bound by theory, the applicant has found that when using waste materials in the foam glass production process, it is possible to (re)introduce oxidizing agents (e.g., all forms of manganese oxides such as MnO2 and MnO; all forms of nitrates such as NaNO3; all forms of iron oxides such as Fe2O3; and all forms of sulfates such as Na2SO4) to achieve a suitable threshold of oxidizing agent in the batch (since they are consumed during foaming and thus the waste materials have an insufficient residual concentration). However, introducing a large amount of oxidizing agent into the glass batch can change the glass composition and may thus have a negative impact on the desired properties of the foam glass product (e.g., thermal conductivity, strength), or may increase environmental emissions (e.g., SO x 、NO x ).

[0039] One such oxidizing agent for the foam glass production process is MnO. Although the oxidizing agent including MnO may be described herein in a specific oxidation state, it should be understood that the oxidizing agent may alternatively be present in any oxidation state or mixture of oxidation states (e.g., MnO2, Mn2O3), depending on the circumstances.

[0040] In particular, the foam glass products disclosed herein can be produced from raw materials incorporating at least a portion of waste materials and an increased concentration of oxidizing agent (e.g., >2 wt% vs. <0.4 wt%), while maintaining the desired properties of the foam glass product such as closed cell content, thermal insulation ability, gas tightness (water vapor impermeability), and mechanical strength.

[0041] In certain embodiments, the overall inventive concept contemplates a foam glass product that includes at least a portion of waste material and has a specific oxide content. In any of the exemplary embodiments, the foam glass product can include manganese oxide in an amount of at least 2 weight percent of the foam glass product (described herein as MnO for simplicity, but it should be understood that manganese can exist in multiple oxidation states or a mixture of oxidation states, and one of ordinary skill in the art will understand that MnO2 is the most likely form of the oxide that will be added to the melter. It should be noted that the waste material added to the melter also contains a certain amount of MnO, as described above). In certain exemplary embodiments, the foam glass product includes MnO in an amount of up to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.1 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.2 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.3 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.4 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.5 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.6 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass includes MnO in an amount of 2.7 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.8 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 2.9 weight percent to 10 weight percent of the foam glass product, including any endpoints and subranges therebetween. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3.1 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3.2 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3.3 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3.4 weight percent to 10 weight percent of the foam glass product. In certain exemplary embodiments, the foam glass product includes MnO in an amount of 3.5 weight percent to 10 weight percent of the foam glass product.In certain exemplary embodiments, the foam glass product contains MnO in an amount of 3.6 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 3.7 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 3.8 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 3.9 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.1 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.2 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.3 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.4 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass contains MnO in an amount of 4.5 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.6 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.7 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.8 wt% to 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 4.9 wt% to 10 wt% of the foam glass product, including any endpoints and subranges therebetween.

[0042] In any of the exemplary embodiments, the foam glass product can contain MnO in an amount of at least 2 wt% to at most 10 wt% of the foam glass product. In certain exemplary embodiments, the foam glass product contains MnO in an amount of 2.1 wt% to 10 wt% of the foam glass product, including, for example, amounts of 2.1 wt% to 8 wt%, 2.3 wt% to 7.5 wt%, 2.5 wt% to 7.2 wt%, 2.7 wt% to 7 wt%, 2.9 wt% to 6.7 wt%, 3.0 wt% to 6.5 wt%, 3.2 wt% to 6.3 wt%, 3.5 wt% to 6 wt%, and 3.7 wt% to 5.8 wt% of the foam glass product, including any endpoints and subranges therebetween.

[0043] In any of the exemplary embodiments, the foamed glass product comprises at least 2 wt% of the foamed glass material, including, for example, amounts of MnO in the foamed glass product of at least 2.5 wt%, at least 3 wt%, at least 3.5 wt%, at least 4 wt%, at least 4.2 wt%, 4.4 wt%, 4.6 wt% and 4.8 wt%, including any endpoints and subranges therebetween.

[0044] In certain exemplary embodiments, the foamed glass product comprises an amount of MnO in the foamed glass product of 5 wt% to 10 wt%. In certain exemplary embodiments, the foamed glass product comprises an amount of MnO in the foamed glass product of 6 wt% to 10 wt%. In certain exemplary embodiments, the foamed glass product comprises an amount of MnO in the foamed glass product of 7 wt% to 10 wt%. In certain exemplary embodiments, the foamed glass product comprises an amount of MnO in the foamed glass product of 8 wt% to 10 wt%. In certain exemplary embodiments, the foamed glass product comprises an amount of MnO in the foamed glass product of 9 wt% to 10 wt%, including any endpoints and subranges therebetween.

[0045] In addition to the above oxidizing agent, the foamed glass product is produced from a glass composition comprising various oxides such as SiO2, Al2O3, alkaline earth metal oxides, alkali metal oxides and iron oxides. For example, based on the total weight of the glass composition, the glass composition may comprise an amount of SiO2 of 55 wt% to 75 wt%; an amount of Al2O3 of 1 wt% to 10 wt%; an amount of CaO + MgO of 4 wt% to 11 wt%; an amount of Na2O + K2O + Li2O of 12 wt% to 18 wt%; an amount of SO3 of 0.2 wt% to 0.9 wt%; an amount of Fe2O3 of 1 wt% to 6 wt%; an amount of BaO + SrO of 0 wt% to 0.3 wt%; and an amount of TiO2 of 0 wt% to 0.5 wt%. Additionally, based on the total weight of the glass composition or the foamed glass product, an oxidizing agent such as MnO may be included in an amount of 2 wt% to 10 wt%.

[0046] In certain exemplary embodiments, the glass composition comprises an amount of MnO in the glass composition or the foamed glass product of 2 wt% to 10 wt%, an amount of SiO2 of 55 wt% to 75 wt%; an amount of Al2O3 of 1 wt% to 10 wt%; an amount of CaO + MgO of 4 wt% to 11 wt%; an amount of Na2O + K2O + Li2O of 12 wt% to 18 wt%; an amount of SO3 of 0.2 wt% to 0.9 wt%; an amount of Fe2O3 of 1 wt% to 6 wt%; an amount of BaO + SrO of 0 wt% to 0.3 wt%; and an amount of TiO2 of 0 wt% to 0.5 wt%.

[0047] Notwithstanding the foregoing, in some exemplary embodiments, when combined with BaO, SrO, or a combination thereof, the glass composition may contain an amount of MnO less than 2%. Thus, in certain exemplary embodiments, when used in a composition containing at least 0.3 wt% of BaO + SrO, the glass composition contains 0.4 wt% to 10 wt% of MnO. In such embodiments, when used in a composition containing 0.5 wt% to 5 wt% of BaO + SrO (such as, for example, 0.7 wt% to 3 wt%, and 0.9 wt% to 1.5 wt%), the glass composition may contain 0.4 wt% to less than 10 wt% of MnO, including, for example, 0.5 wt% to 8 wt% of MnO, 0.5 wt% to 6 wt%, and 0.8 wt% to 5 wt% of MnO.

[0048] Accordingly, various exemplary embodiments of the inventive concept relate to a glass composition comprising a combination of an amount of MnO from 0.4 wt% to 10 wt% with at least one of BaO and SrO, and at least one of the following: an amount of SiO2 from 55 wt% to 75 wt%; an amount of Al2O3 from 1 wt% to 10 wt%; an amount of CaO + MgO from 4 wt% to 11 wt%; an amount of Na2O + K2O + Li2O from 12 wt% to 18 wt%; an amount of SO3 from 0.2 wt% to 0.9 wt%; an amount of Fe2O3 from 1 wt% to 6 wt%; and an amount of TiO2 from 0 wt% to 0.5 wt%. In certain exemplary embodiments, the glass composition comprises a combination of an amount of MnO from 0.4 wt% to 10 wt% with at least one of BaO and SrO, and 55 wt% to 75 wt% of SiO2; 1 wt% to 10 wt% of Al2O3; 4 wt% to 11 wt% of CaO + MgO; 12 wt% to 18 wt% of Na2O + K2O + Li2O; 0.2 wt% to 0.9 wt% of SO3; 1 wt% to 6 wt% of Fe2O3; and 0 wt% to 0.5 wt% of TiO2.

[0049] As mentioned, in certain exemplary embodiments, the glass composition for producing a foamed glass product will contain a specific amount or range of other components, including but not limited to SiO2, Al2O3, CaO, MgO, Na2O, K2O, Li2O, SO3, Fe2O3, BaO, SrO, and TiO2, individually or in combination with each other.

[0050] Thus, in certain exemplary embodiments, in addition to MnO, the glass composition further comprises at least 55 wt% but no greater than 75 wt% of SiO2, including for example at least 57 wt%, including at least 59 wt%, at least 60 wt%, at least 62 wt% and at least 64 wt% of SiO2. As mentioned above, the glass composition comprises no greater than 75 wt%, including no greater than 72 wt%, no greater than 70 wt%, no greater than 68 wt%, no greater than 67 wt% and no greater than 66 wt% of SiO2. In addition to MnO, the glass composition further comprises at least 1 wt% of Al2O3. In certain exemplary embodiments, the glass composition comprises less than 10 wt% of Al2O3. In certain exemplary embodiments, based on the weight of the glass composition or the foamed glass product produced therefrom, the glass composition comprises from 1 wt% to 10 wt%, including from 1 wt% to 9 wt%, including from 1 wt% to 8 wt%, including from 2 wt% to 10 wt%, including from 3 wt% to 10 wt%, including from 4 wt% to 10 wt%, including from 4.5 wt% to 10 wt%, and including from 4.5 wt% to 8 wt% of Al2O3.

[0051] The glass composition further comprises a total amount of at least 4 wt% of CaO + MgO. In certain exemplary embodiments, the glass composition comprises less than 11 wt% of CaO + MgO. In certain exemplary embodiments, based on the weight of the glass composition or the foamed glass product produced therefrom, the glass composition comprises from 4 wt% to 11 wt%, including from 5 wt% to 10 wt%, including from 5.5 wt% to 9 wt%, and including from 6 wt% to 8.5 wt% of CaO + MgO.

[0052] In addition, the glass composition for producing a foamed glass product comprises a total amount of at least 12 wt% of Na2O, K2O and / or Li2O. In certain exemplary embodiments, the glass composition comprises a total amount of less than 18 wt% of Na2O, K2O and / or Li2O. In certain exemplary embodiments, based on the weight of the glass composition or the foamed glass product produced therefrom, the glass composition comprises a total amount of from 12 wt% to 18 wt%, including from 12.5 wt% to 17 wt%, including from 12.8 wt% to 16.5 wt%, including from 13 wt% to 16 wt%, including from 14 wt% to 18 wt%, and including from 14 wt% to 16.5 wt% of Na2O, K2O and / or Li2O.

[0053] The glass composition further comprises SO3 in an amount of at least 0.2 wt%. In certain exemplary embodiments, the glass composition comprises less than 1 wt% of SO3. In certain exemplary embodiments, based on the weight of the glass composition or the foam glass product produced therefrom, the glass composition comprises from greater than 0.2 wt% to 0.9 wt%, including from 0.3 wt% to 0.8 wt%, including from 0.4 wt% to 0.9 wt%, including from 0.2 wt% to 0.8 wt%, and including from 0.4 wt% to 0.7 wt% of SO3.

[0054] The glass composition for producing a foam glass product further comprises Fe2O3 in an amount of at least 1 wt%. In certain exemplary embodiments, the glass composition comprises less than 6 wt% of Fe2O3. In certain exemplary embodiments, based on the weight of the glass composition or the foam glass product produced therefrom, the glass composition comprises from 1 wt% to 5 wt%, including from 1.2 wt% to 4.7 wt%, including from 1.3 wt% to 4.5 wt%, including from 2 wt% to 6 wt%, including from 2.5 wt% to 5.8 wt%, including from 2.8 wt% to 5.5 wt%, and including from 2.8 wt% to 4.5 wt% of Fe2O3.

[0055] In certain exemplary embodiments, in addition to MnO, the glass composition further comprises a total amount of BaO + SrO of less than 0.3 wt%. In certain exemplary embodiments, the glass composition comprises from 0 wt% to 0.1 wt% (i.e., trace amounts), including from 0.01 wt% to 0.2 wt%, including from 0.05 wt% to 0.25 wt%, including from 0.1 wt% to 0.2 wt%, and including from 0.1 wt% to 3 wt% of BaO + SrO. It should be understood that in certain embodiments, as previously discussed for various embodiments including lower amounts of MnO, higher amounts of BaO + SrO (e.g., from 0.3 wt% to 2 wt%) may be present.

[0056] The glass composition for producing a foam glass product may further comprise TiO2 in an amount of less than 0.5 wt%. In certain exemplary embodiments, based on the weight of the glass composition or the foam glass product produced therefrom, the glass composition comprises from 0.01 wt% to 0.5 wt%, including from 0.05 wt% to 0.4 wt%, including from 0.1 wt% to 0.3 wt%, including from 0.15 wt% to 0.2 wt%, including less than 0.4 wt%, including less than 0.3 wt%, including less than 0.2 wt%, and including less than 0.1 wt% of TiO2.

[0057] In certain embodiments, the amount of MnO (along with other oxides) is determined by XRF (X-ray fluorescence). One of ordinary skill in the art will understand that XRF measures the amount of Mn and is typically reported as MnO, regardless of the actual oxidation state. For the purposes of this application, the Mn detected by XRF will be discussed as if it were in the MnO oxidation state.

[0058] The following table lists exemplary ranges of the oxide content of the foam glass products made in accordance with the general inventive concept.

[0059] Table 1

[0060]

[0061] In any of the various exemplary embodiments, the foam glass product contains MnO in an amount of 2 wt% to 10 wt% and has a thermal conductivity of less than or equal to 0.06 W / mK, less than or equal to 0.05 W / mK, and less than or equal to 0.045 W / mK (including 0.033 W / mK to 0.042 W / mK). For the purposes disclosed herein, the thermal conductivity is measured according to the EN 12667 standard.

[0062] In any of the exemplary embodiments, the foam glass product may contain MnO in an amount of 2 wt% to 10 wt% and have a density of less than 300 kg / m 3 , including between 75 kg / m 3 and 300 kg / m 3 , including between 90 kg / m 3 and 250 kg / m 3 , including between 100 kg / m 3 and 200 kg / m 3 , including between 80 kg / m 3 and 140 kg / m 3 , including less than 200 kg / m 3 , and including less than 150 kg / m 3Density. In any of the exemplary embodiments, the foam glass product contains MnO2 in an amount of 2 wt% to 10 wt%, and is at least substantially (i.e., at least 80%) closed-cell, or completely (i.e., 100%) closed-cell. In any of the exemplary embodiments, the foam glass product contains MnO in an amount of 2 wt% to 10 wt% and has a compressive strength greater than 0.4 MPa, including 0.4 MPa to 2.5 MPa, including 0.4 MPa to 2.4 MPa, including 0.4 MPa to 2 MPa, including 0.4 MPa to 1.75 MPa, including 0.45 MPa to 1.5 MPa, including 0.5 MPa to 1.45 MPa, including 0.6 to 1.4 MPa, including 0.7 to 1.3 MPa, including 0.8 MPa to 1.25 MPa, and including 0.85 MPa to 1.2 MPa. For the purposes disclosed herein, the compressive strength is measured according to the EN 826 standard.

[0063] In any of the various exemplary embodiments, the foamable glass for producing the foam glass product has a room temperature thermal conductivity of less than 1.1 W / mK, including less than 1.0 W / mK. In any of the various exemplary embodiments, the foamable glass has a modulus of elasticity greater than 60 GPa, including greater than 65 GPa, including greater than 70 GPa, and including greater than 75 GPa.

[0064] The general inventive concept also contemplates methods of recycling waste materials and methods of producing foam glass products that include at least a portion of waste materials and / or recycled cullet. As described herein, the method incorporates waste materials into the production of a foam glass product that contains an increased amount of an oxidizing agent (e.g., MnO, MnO2), while maintaining certain desired properties of the foam glass product. It should be understood that the foregoing discussion of the glass composition equally applies to the methods described herein. That is, the methods according to the concepts discussed herein employ the glass compositions and component (e.g., oxide) values discussed herein.

[0065] Various exemplary embodiments disclose methods for producing foam glass products that include at least a portion of waste material or recycled cullet. The method includes providing a source of raw glass material in a melter, where the raw glass material includes two or more of virgin glass material, waste material, and recycled cullet; providing a source of oxidizer to the melter and mixing the oxidizer with the raw glass material to form a glass melt, where the oxidizer is included in an amount to achieve a predetermined level of oxidizer in the glass melt; cooling the glass melt; and subjecting the resulting glass material to a foam glass production process. In certain exemplary embodiments, the glass includes an amount of oxidizer of at least 2 wt% (including 2 wt% to 10 wt%). In certain embodiments, the waste material may be combined with the raw glass material / virgin glass material in the melter to form a combined glass melt.

[0066] In any of the exemplary embodiments, waste glass material may be present in the raw materials or glass melt in an amount of 10% to 60% (including 20% to 50%), and in some exemplary embodiments, the waste material may be present in an amount greater than 60% (including 100%). In certain exemplary embodiments, recycled cullet may account for about 20% to about 60% of the material in the melter, including 20% to 40%, and in certain cases, about 36% of the total weight. In certain exemplary embodiments, the waste material and recycled cullet are combined in an amount up to 85 wt%, including 20 wt% to 85 wt%, and including 40 wt% to 80 wt%. In certain exemplary embodiments, the virgin material and the waste material are present in a weight ratio of 9:1 to 2:3 (including, for example, 4:1 to 1:1).

[0067] As previously mentioned, there is an unmet need for methods that result in a reduction of waste foam glass material ultimately sent to landfills and / or a reduction in the need for virgin glass-making materials for foam glass production (by recycling waste or post-consumer glass). The concepts discussed herein are based in part on the discovery that by introducing an oxidizer directly into the melter and increasing the amount of oxidizer in the melt to a level higher than previously feasible for foam glass insulation, waste material can be reintroduced into the process of foam glass production (whether continuous or batch). The concepts discussed herein are also based in part on the discovery that an increase in the level of MnO in the glass composition for foaming does not have a negative impact on the thermal conductivity and strength of the glass and thus also does not have a negative impact on the thermal conductivity and strength of the foam glass product produced by foaming such glass. This makes MnO2 (discussed herein as MnO in the foam glass product) the preferred oxidizer to achieve elevated levels of waste and / or recycled cullet.

[0068] Example :

[0069] The following examples illustrate exemplary embodiments and / or features of the methods and compositions according to the general inventive concept. The examples are given for illustrative purposes only and should not be construed as limiting the general inventive concept of the present invention, as many variations are possible without departing from the spirit and scope of the general inventive concept of the present invention. Unless otherwise specified, all exemplary amounts are weight percentages based on the total weight of the composition.

[0070] Sample glass compositions A to D (detailed in Table 2) were designed to contain approximately 4 wt% of MnO, which was introduced in the melter during formation.

[0071] The glass compositions were melted, annealed, and poured into rods (for E-modulus measurement) and pucks (for thermal conductivity measurement). The measured glass composition data (in wt%) for samples A to D and two control glasses (Control 1 and 2) are shown in Table 2.

[0072] Table 2

[0073]

[0074] Various measured properties of the annealed glass products are shown in Table 3. The E-modulus, G-modulus (shear modulus), and Poisson's ratio were measured according to ASTM E-1876. The thermal conductivity (ASTM E-1225) was measured by a heat flux meter and the CTE was measured by dilatometry according to ASTM E-228.

[0075] Table 3

[0076] E-modulus [GPa] G-modulus [GPa] Poisson's ratio Thermal conductivity [W / mK] CTE [μm / m.K] Control 1 72 30 0.19 1.036 8.60 Control 2 73 31 0.18 8.65 Sample A 71 30 0.19 1.002 9.07 Sample B 69 29 0.18 0.999 8.77 Sample C 0.993 8.84 Sample D 66 28 0.17 1.006 8.61

[0077] Samples A to E were also melted, quenched, ground with carbon, and foamed in a vertical tube furnace. The compositional analysis including sulfate retention (in wt%) is shown in Table 4.

[0078] Table 4

[0079]

[0080] A small foam test was conducted to test the foaming property of the glass and provide indications of foam height, pore structure, viscosity, etc. For this test, 50 g of the ground glass with carbon black was loaded into a cylindrical crucible with an 8 cm diameter. The crucible was loaded into a preheated vertical tube furnace with an argon atmosphere. After stabilizing for 20 minutes at an elevated temperature (630 °C) to uniformly heat the powder batch, the temperature was raised at a rate of 8 °C / min. A laser rangefinder measured the batch / foam height through an optical window. When the foam was considered to be at the optimal foam height, the foam was removed from the furnace and loaded into an adiabatic box for annealing. Figure 1 It shows that the sample glass foamed well, although the performance of sample D was slightly worse than that of other samples (e.g., lower height, rough pores). Figure 2 It shows a control foam made from a conventional glass mixture. The dimensions of all the figures were manually adjusted to represent the same scale (approx. equal width of the foam). Many of the foams had "bottom-folded" cavities. Those were considered to be mainly the effects of a small proportion rather than an indication of the glass properties.

[0081] Tested according to the international standard ISO 719:2020 Figure 2 of the hydrolytic resistance of the conventional foam glass sample and sample C. Both were determined to be of hydrolytic resistance class HGB 3.

[0082] Higher manganese samples were prepared using 10% manganese oxide, and the composition of the glass is shown in Table 5 (in wt%). Figure 3 It shows a foam block made using an increased manganese content.

[0083] Table 5

[0084]

[0085] The control glass 1, sample A, and sample C were melted, ground, and used to form foam glass blocks, which were finished into blocks with dimensions of 60×45×10 cm. Figure 4 is a schematic diagram showing the cross-section of each block for each test in a series of tests for foam glass products. Figure 4 It shows the results of the thermal conductivity measurement (EN 12667) of the foam. The thermal conductivities of all the foams were consistent, showing no significant deviation. The overall trend shows that the slopes of all the glasses were very similar. In particular, the test samples exhibited thermal conductivity values in the range of 0.034 W / mK to 0.043 W / mK at foam densities from 84 kg / m 3 to approximately 140 kg / m 3 of the foam density.

[0086] Figure 5Shows the results of the compressive strength measurement (according to EN 826). It is important to note that under production standards, the measured compressive strength values are typically quite variable, and the pilot batches are expected to show even greater variability. That is, the measured values indicate that both samples A and C are performed based on the same standards as conventional production glass. The test samples were shown at a foam density of 90 kg / m 3 to 140 kg / m 3 to exhibit compressive strength values in the range of 0.25 N / mm 2 (i.e., 0.25 MPa) and 1.5 N / mm 2 (i.e., 1.5 MPa). In contrast, Control 1 showed compressive strength values in a similar range.

[0087] As Figure 6 shown, samples A and C showed elastic modulus values in the range of 0.5 GPa and 1 GPa at a foam density of 90 kg / m 3 to 140 kg / m 3 . In contrast, Control 1 showed elastic modulus values in a similar range.

[0088] Water vapor durability . The λ-plates for samples A and reference glasses 1 and 2 were freely mounted above a water bath at 90 °C. The weight gain was monitored over a period of 4 weeks (due to water absorption in the case where the cell walls corrode and water can condense inside the foam). The water vapor durability test according to EN 12086 showed that sample A exhibited similar or even slightly better performance compared to the reference blocks of similar density.

[0089] According to certain embodiments described herein, the sample glass composition G (detailed in Table 6 in weight %) was designed to contain a combination of about 0.5 wt% of MnO and about 1 wt% of BaO + SrO. The glass was melted, annealed, and foamed for testing. The samples were each measured at a foam density of 113 to 118.7 kg / m 3 .

[0090] Table 6

[0091]

[0092] Table 7 shows the experimental results for each of the three parts of sample G glass, regarding the E-modulus, G-modulus, and Poisson's ratio of the glass, as well as the thermal conductivity, compressive strength, and coefficient of thermal expansion of the foam produced from the glass. This shows that it is possible to manufacture foam glass products (manufactured according to the general inventive concept) including a glass composition having a combination of about 0.4 wt% of MnO and a BaO + SrO value between about 0.3 wt% and 2 wt%, while maintaining the important / desirable properties of foam glass insulation.

[0093] Table 7

[0094]

[0095] A control glass prepared using a conventional glass mixture was melted and annealed together with two experimental glasses (Samples I and J). The experimental glasses were designed to contain from about 0.4 wt% to 2 wt% of MnO and from 0.3 to 2 wt% of BaO + SrO. The compositions of the glasses are shown in Table 8 (in wt%).

[0096] Table 8

[0097]

[0098] Table 9 shows the results of measuring the E-modulus, G-modulus, Poisson's ratio, and CTE of the glasses shown in Table 8. Those bulk glass properties are suitable for producing foam glass products. This demonstrates that foam glass products (manufactured according to the general inventive concept) comprising a glass composition having a combination of about 0.4 wt% of MnO and a BaO + SrO value between about 0.3 wt% and 2 wt% can be manufactured and retain the important / desired properties of foam glass insulation as compared to conventional glasses.

[0099] Table 9

[0100] E-modulus [GPa] G-modulus [GPa] Poisson's ratio CTE [μm / m.K] Sample H 73 31 0.18 8.65 Sample I 74 31 0.19 8.62 Sample J 71 30 0.19 8.90

[0101] Table 10

[0102] Table 10 shows the measurement results of the weight percentages of FeO and SO3 measured after melting Samples G to J in an air atmosphere or in the presence of a nitrogen atmosphere. This thus demonstrates that there are similar amounts of total Fe in the melted glasses.

[0103]

[0104]

[0105] As used in the description of the sizing compositions disclosed herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. All references incorporated herein by reference are incorporated in their entirety unless otherwise specified. Unless otherwise indicated (e.g., by use of the term "exactly"), all numbers expressing quantities, properties such as molecular weight, reaction conditions, etc., as used in this disclosure are to be understood as being modified in all instances by the term "about." Accordingly, unless otherwise indicated, the numerical properties set forth in this disclosure are approximations that may vary depending upon the desired properties sought to be obtained in the embodiments described herein.

[0106] As disclosed and proposed herein, the general concept of this disclosure relates to and contemplates improvements to foam glass products, and more particularly, to methods of producing foam glass products using modified waste foam glass and / or foam glass having an increased amount of an oxidizing agent (e.g., MnO or MnO2). The scope of the general concept is not intended to be limited to the specific exemplary embodiments shown and described herein. Based on the disclosure provided, those skilled in the art will not only understand the general concept and its attendant advantages, but will also discover various obvious changes and modifications to the compositions and methods. Accordingly, all such changes and modifications and any equivalents thereof that fall within the spirit and scope of the general concept as described and proposed herein are sought to be covered.

Claims

1. A foam glass product produced from a glass composition, the glass composition comprising: MnO source in an amount of 2 wt% to 10 wt%; SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; and BaO + SrO in an amount of 0 wt% to 0.3 wt%, wherein the foam glass product satisfies at least one of the following properties; The foam glass product is a closed-cell foam; The foamed glass product has a density of about 75 kg / m 3 to 300 kg / m 3 ; The foam glass product has a thermal conductivity of 0.033 W / mK to 0.06 W / mK; and The foam glass product has a compressive strength of 0.4 MPa to 2.5 MPa.

2. The foam glass product according to claim 1, wherein the glass composition comprises SiO2 in an amount of 60 wt% to 70 wt%.

3. The foam glass product according to any one of the preceding claims, wherein the glass composition comprises Al2O3 in an amount of 2 wt% to 7 wt%.

4. The foam glass product according to any one of the preceding claims, wherein the glass composition comprises CaO + MgO in an amount of 5 wt% to 9 wt%.

5. The foam glass product according to any one of the preceding claims, wherein the glass composition further comprises SO3 in an amount of 0.2 wt% to 0.9 wt%.

6. The foam glass product according to any one of the preceding claims, wherein the glass composition further comprises Fe2O3 in an amount of 1 wt% to 6 wt%.

7. The foam glass product according to any one of the preceding claims, wherein the glass composition further comprises TiO2 in an amount of 0 wt% to 0.5 wt%.

8. The foam glass product according to any one of the preceding claims, wherein the foam glass product comprises at least 20 wt% of waste material or recycled cullet.

9. The foam glass product according to any one of the preceding claims, wherein the foam glass product comprises 30 wt% to 85 wt% of waste material or recycled cullet.

10. The foam glass product according to any one of the preceding claims, wherein the foam glass product has a thermal conductivity of 0.033 W / mK to 0.042 W / mK.

11. The foam glass product according to any one of the preceding claims, wherein the foam glass product has a compressive strength of 0.5 MPa to 1.45 MPa.

12. The foam glass product according to any one of the preceding claims, wherein the MnO source is present in the glass composition in an amount of 3 wt% to 8 wt%.

13. The foam glass product according to any one of the preceding claims, wherein the MnO source is present in the glass composition in an amount of 4 wt% to 6 wt%.

14. A foam glass product produced from a glass composition, the glass composition comprising: MnO source in an amount of 0.4 wt% to 2 wt%; BaO + SrO in an amount of 0.3 wt% to 2 wt%; and at least one of the following: SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%, wherein the foam glass product satisfies at least one of the following: The foam glass product is a substantially closed-cell foam; The foamed glass product has a density of about 75 kg / m 3 to 300 kg / m 3 ; The foam glass product has a thermal conductivity of 0.033 W / mK to 0.06 W / mK; and The foam glass product has a compressive strength of 0.4 MPa to 2.5 MPa.

15. The foam glass product according to claim 14, wherein the glass composition comprises SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; SO3 in an amount of 0.2 wt% to 0.9 wt%; Fe2O3 in an amount of 1 wt% to 6 wt%; and TiO2 in an amount of 0 wt% to 0.5 wt%.

16. The foam glass product according to claim 14 or claim 15, wherein the foam glass product is a closed-cell foam and has a density of about 75 kg / m 3 to 300 kg / m 3 ; a thermal conductivity of 0.033 W / mK to 0.06 W / mK; and a compressive strength of 0.4 MPa to 2.4 MPa.

17. The foam glass product according to claim 1 or claim 14, wherein the foamable glass material for forming the foam glass product comprises at least 20 wt% of waste material or recycled cullet.

18. A method for producing a foam glass product, the foam glass product comprising at least a portion of waste material or recycled cullet, the method comprising: Providing a source of raw glass material in a melter, wherein the raw glass material comprises two or more of virgin glass material, waste material, and recycled cullet; Providing a source of oxidant to the melter and mixing the oxidant with the raw glass material to form a glass melt, wherein the oxidant is included in an amount to achieve a predetermined level of the oxidant in the glass melt; Cooling the glass melt; And Subjecting the resulting glass material to a foam glass production process.

19. The method according to claim 18, wherein the predetermined level of the oxidant is 2 wt% to 10 wt%.

20. The method according to claim 18, wherein the predetermined level of the oxidant is 0.4 wt% to 2 wt%, and the glass material further comprises a combined amount of BaO + SrO in an amount of 0.3 wt% to 2 wt%.

21. The method according to any one of claims 18 to 20, wherein the glass material comprises: SiO2 in an amount of 55 wt% to 75 wt%; Al2O3 in an amount of 1 wt% to 10 wt%; CaO + MgO in an amount of 4 wt% to 11 wt%; Na2O + K2O + Li2O in an amount of 12 wt% to 18 wt%; SO3 in an amount of 0.2 wt% to 0.9 wt%; Fe2O3 in an amount of 1 wt% to 6 wt%; and TiO2 in an amount of 0 wt% to 0.5 wt%.

22. The method according to any one of claims 18 to 21, wherein the oxidant is MnO2, MnO, or a combination thereof.

23. The method according to any one of claims 18 to 22, wherein the raw material and the waste material are present in the foamable glass material in a ratio of 9:1 to 2:3 by weight.

24. The method according to any one of claims 18 to 23, wherein the foamed glass product has one or more of the following properties: a. The foamed glass product is a substantially closed-cell foam; b. The foam glass product has a density of about 75 kg / m 3 to 300 kg / m 3 ; c. The foamed glass product has a thermal conductivity of less than 0.06 W / mK; and d. The foamed glass product has a compressive strength of 0.4 MPa to 2.5 MPa.

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