Glass-ceramics

Abstract

To provide glass that has a good appearance even when it contains impurity components and has excellent melting properties. The present invention provides a composition comprising, in mass % oxide equivalent, 40.0% to 70.0% of an SiO2 component, 11.0% to 25.0% of an Al2O3 component, 3.0% to 19.0% of a Na2O component, 0.5 to 12.0% of a TiO2 component, 0% to 15.0% of an Fe2O3 component, 0% to 4.0% of a CoO+Co3O4 component, and over 0% to 19.0% of a Fe2O3+CoO+Co3O4 component, as well as V, Ga, A A crystallized glass containing a component containing at least one element selected from the group consisting of S, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each of these elements, when present, being greater than 0% and not more than 2%.

Description

[Technical Field]

[0001] The present invention relates to glass-ceramics. [Background technology]

[0002] In recent years, there has been an increasing demand for glass to be used as the housing (exterior) of electronic devices such as smartphones and tablet PCs. Glass for these applications is also required to have the strength and hardness to withstand harsh use. Patent Document 1, for example, discloses crystallized glass that has various physical properties required for an information recording medium substrate, as glass that can provide high strength and hardness. However, no studies have been conducted on glass that is suitable for housings. When glass is used as the housing of an electronic device, it may be colored according to the design, or the color tone may be adjusted to block light from the internal components and prevent it from leaking to the outside.

[0003] In recent years, the importance of recycling has increased from the perspective of reducing carbon dioxide emissions, and expectations are also high for glass recycling. Glass is highly recyclable because it is relatively easy to reshape by heating and melting, and the amount of carbon dioxide emitted during the recycling process can be kept low, and it is expected to contribute to reducing carbon footprints.

[0004] On the other hand, many glass components recovered from used electronic devices and the like are integrated with metal, organic, or ceramic materials, and it is usually difficult to completely separate these materials from the glass and recover them (e.g., Non-Patent Document 1). For this reason, it is difficult to avoid components derived from the integrated metal materials being mixed into recycled products as impurities, making it difficult to produce recycled products that are equivalent to those before recovery, and therefore the glass recycling rate remains low. In particular, the change in appearance of glass before and after recycling is easily noticeable, which hinders improvements in the recycling rate. Therefore, there is a demand for glass that can maintain the excellent appearance unique to glass even after reuse. Furthermore, there is a demand for glass with excellent melting properties to facilitate subsequent recycling. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-114200 [Non-patent literature]

[0006] [Non-Patent Document 1] Masaru Hanawa, "Special Feature: Companies Supporting the Ceramics Industry with Chemical Technology (2023) AGC Inc. - Current Status and Issues of Plate Glass Recycling", Ceramics, Ceramic Society of Japan, March 2023, Vol. 58, No. 3, pp. 149-152 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a glass that has a good appearance and excellent melting properties even when it contains impurity components. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that crystallized glass having a specific composition retains the excellent appearance characteristic of glass even when it contains impurity components, and also has excellent melting properties, and have thus completed the present invention. According to the present invention, the following crystallized glass and the like are provided. (Configuration 1) In terms of oxide, mass % SiO2 content: 40.0% to 70.0% Al2O3 component 11.0% to 25.0%, Na2O content: 3.0% to 19.0% TiO2 component 0.5 to 12.0%, Fe2O3 content: 0% to 15.0% CoO+Co3O4 component 0% to 4.0%, Fe2O3+CoO+Co3O4 components exceeding 0% to 19.0%, and A component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each element, when present, being more than 0% and 2% or less, Crystallized glass. (Configuration 2) In terms of oxide, mass % K2O content: 0% to 9.0% 2. The crystallized glass according to claim 1, containing 1.0% to 20.0% of one or more selected from MgO and ZnO, and 0% to 3.0% of CaO. (Configuration 3) In terms of oxide, mass % TiO2 component 4.0% to 10.0%, Fe2O3 content of 2.0% to 12.0%, and 3. The crystallized glass according to claim 1 or 2, containing 0.05% to 0.5% of one or more selected from the group consisting of CoO and Co3O4 components. (Configuration 4) In terms of oxide, mass % SiO2 content: 45.0% to 65.0% Al2O3 component 13.0% to 23.0%, Na2O content: 8.0% to 16.0% K2O content: 0.1% to 9.0% 2.0% to 20.0% of one or more selected from MgO and ZnO components; 3. The crystallized glass according to claim 1 or 2, which contains 0.01% to 3.0% of a CaO component. (Configuration 5) 3. The crystallized glass according to claim 1 or 2, having a Vickers hardness of 550 or more. (Configuration 6) 3. The crystallized glass according to claim 1, wherein a1* is in the range of -0.10 to 0.12, b1* is in the range of -2.00 to 0.10, and L1* is in the range of 20.0 to 30.0 in the CIELAB color space coordinates determined from a reflectance spectrum including regular reflection measured with a spectrophotometer under the following conditions using CIE illuminant D65 at an observer angle of 10°. (Reflectance spectrum measurement conditions) Sample thickness: 4 mm Light receiving angle relative to the normal to the sample surface: 8° (Configuration 7) In terms of oxide, mass % SiO2 content: 40.0% to 70.0% Al2O3 component 11.0% to 25.0%, Na2O content: 3.0% to 19.0% TiO2 component 0.5 to 12.0%, Fe2O3 content: 0% to 15.0% CoO+Co3O4 component 0% to 4.0%, Fe2O3+CoO+Co3O4 components exceeding 0% to 19.0%, and A method for recycling crystallized glass, comprising heating and melting crystallized glass containing a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, each of which, when present, has a content of more than 0% and 2% or less, and crystallizing the crystallized glass. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide glass that has a good appearance and excellent melting properties even when it contains impurity components. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing XRD spectra of the crystallized glasses of Example 6, Comparative Example 1, and Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes in detail the embodiments and examples of the crystallized glass of the present invention, but the present invention is not limited to the following embodiments and examples, and can be practiced with appropriate modifications within the scope of the object of the present invention.

[0012] [Glass-ceramics] The crystallized glass according to one embodiment of the present invention comprises, in mass % in terms of oxides: SiO2 content: 40.0% to 70.0% Al2O3 component 11.0% to 25.0%, Na2O content: 3.0% to 19.0% TiO2 component 0.5 to 12.0%, Fe2O3 content: 0% to 15.0% CoO+Co3O4 component 0% to 4.0% Fe2O3+CoO+Co3O4 components exceeding 0% to 19.0%, and The composition contains at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, and when present, the content of each element is more than 0% and 2% or less.

[0013] The crystallized glass according to one embodiment of the present invention exhibits a good appearance with the smoothness and smooth luster of glass even when containing impurity components, and can maintain a color tone equivalent to that of glass without impurity components. It also has excellent melting properties, and a homogeneous melt is easily obtained when melted. Therefore, the crystallized glass is easy to use as a product even when recycled, and is also an excellent raw material for recycling, so it is expected to contribute to improving the recycling rate.

[0014] In this specification, the impurity component refers to a component (e.g., an oxide) containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, as will be described in detail later.

[0015] <Components> The constituent components of the crystallized glass of the present invention will be described. In this specification, the content of each component is expressed in mass% converted to oxide unless otherwise specified. Here, "oxide conversion" refers to the amount of oxide of each component contained in the crystallized glass, expressed in mass%, when the total mass of the oxides is 100 mass%, assuming that all the constituent components of the crystallized glass are decomposed and converted to oxides. In this specification, A% to B% means A% or more and B% or less.

[0016] The SiO2 component is an essential component for forming the glass network structure of glass-ceramics. By making the amount 40% or more, the chemical durability of the resulting glass can be improved and devitrification can be suppressed. On the other hand, by making the SiO2 component content 70% or less, excessive increases in viscosity and deterioration of meltability can be suppressed. Therefore, the SiO2 content is 40.0% to 70.0%, or alternatively, 45.0% to 65.0%, or 50.0% to 60.0%.

[0017] The Al2O3 component is an essential component that forms a glass network structure, similar to SiO2, and can also become a component that forms a crystalline phase when the raw glass is heat-treated before crystallization. It also contributes to stabilizing the raw glass and improving its chemical durability, and a content of 11.0% or more provides excellent effects. On the other hand, by keeping the Al2O3 content at 25% or less, deterioration of meltability and devitrification can be suppressed. Therefore, the content of the Al2O3 component is 11.0% to 25.0%, but may also be 13.0% to 23.0%, or 15.0% to 21.0%.

[0018] The Na2O component is an essential component for improving low-temperature melting properties and formability. Furthermore, a high Na2O content enhances chemical strengthening. On the other hand, by keeping the Na2O content at 19% or less, deterioration of chemical durability can be prevented. Therefore, the Na2O content is 3.0% to 19.0%, may be 5.0% to 18.0%, or may be 8.0% to 16.0%. The Na2O content may be 9.0% or more, or 10.5% or more.

[0019] The K2O component is an optional component that contributes to improving the low-temperature melting property and formability of the glass. On the other hand, by setting the content of the K2O component to 9.0% or less, it is possible to prevent deterioration of chemical durability. Therefore, the content of the K2O component may be in the range of 9.0% or less. The content of the K2O component may be 0.1% to 9.0%, 0.1% to 8.0%, 0.1% to 7.0%, or 0.2% to 5.0%.

[0020] The inclusion of 1.0% or more of one or more components selected from the MgO component and the ZnO component has the effect of improving low-temperature melting properties. On the other hand, the inclusion of 20.0% or less of one or more components selected from the MgO component and the ZnO component can prevent deterioration of devitrification properties. Therefore, the inclusion of 1.0% to 20.0% of one or more components selected from the MgO component and the ZnO component may be present. The "inclusion of 1 or more components selected from the MgO component and the ZnO component" refers to the total content of the MgO component and the ZnO component. The content of one or more selected from the MgO component and the ZnO component may be 2.0% to 20.0%, 2.0% to 19.0%, 3.0% to 18.0%, or 5.0% to 17.5%. The phrase "containing one or more selected from MgO and ZnO" means containing only MgO, only ZnO, or both MgO and ZnO, but preferably containing only MgO. The MgO can also be a component that forms a crystalline phase by heat treatment of the base glass before crystallization.

[0021] The CaO component is an optional component that contributes to improving the low-temperature melting property of the glass when contained in an amount exceeding 0%. On the other hand, by setting the CaO component to 5.0% or less, it is possible to suppress deterioration of devitrification. Therefore, the content of the CaO component may be in the range of 5.0% or less. The content of the CaO component may be 0% to 3.0%, 0.01% to 3.0%, or 0.1% to 2.0%.

[0022] The TiO2 component plays a role in nucleation for crystal precipitation, and contributes to lowering the viscosity of the crystallized glass, improving chemical durability, and coloring the crystallized glass. A TiO2 component content of 0.5% or more provides excellent effects. On the other hand, a TiO2 component content of 12.0% or less can prevent deterioration of devitrification. Therefore, the TiO2 component content is 0.5 to 12.0%, and may be 3.0% to 11.5%, 3.5% to 11.0%, or 4.0% to 10.0%. The TiO2 component content may be 4.1% or more, or 4.3% or more.

[0023] The Fe2O3 component is an optional component that can form a crystalline phase, acts as a fining agent, and contributes to the coloring of crystallized glass. These effects are achieved when the Fe2O3 component is contained in an amount exceeding 0%. On the other hand, by keeping the Fe2O3 content at 15.0% or less, it is possible to suppress deterioration of devitrification, excessive coloring, and alloying of platinum used in glass melting equipment. The Fe2O3 component content is 0% to 15.0%, and may be 1.5% to 14.0%, 2.0% to 12.0%, or 2.1% to 10.0%.

[0024] When the content of one or more components selected from the CoO component and the Co3O4 component (CoO + Co3O4 component) exceeds 0%, the component may contribute to coloring of the crystallized glass. On the other hand, by setting the content of one or more components selected from the CoO component and the Co3O4 component (CoO + Co3O4 component) to 4.0% or less, it is possible to suppress deterioration of devitrification and excessive coloring. The content of one or more components selected from the CoO component and the Co3O4 component (CoO + Co3O4 component) is 0% to 4.0%. "The content of one or more components selected from the CoO component and the Co3O4 component" means the total content of the CoO component and the Co3O4 component. The content of one or more selected from the CoO component and the Co3O4 component may be 0.01% to 2.0%, may be 0.03% to 0.8%, or may be 0.05% to 0.5%.

[0025] In order to provide the desired color of the glass-ceramics while maintaining excellent resistance to devitrification, the content of the Fe2O3+CoO+Co3O4 components is more than 0% and 19.0% or less. The "content of the Fe2O3+CoO+Co3O4 components" means the total content of the Fe2O3 component, the CoO component, and the Co3O4 component. The content of the Fe2O3+CoO+Co3O4 component may be 0.1% to 15.0%, may be 0.5% to 10.0%, or may be 1.0% to 5.0%.

[0026] Crystallized glass usually contains the following impurity components, which are oxides of the above-mentioned impurity elements: V2O5 component, Ga2O3 component, As2O3 component, GeO2 component, SeO2 component, Y2O3 component, ZrO2 component, NbO component, RuO2 component, Rh2O3 component, PdO component, CdO component, In2O3 component, Sb2O3 component, TeO2 component, HfO2 component, Ta2O3 component, ReO3 component, OsO4 component, IrO2 component, HgO component, Tl2O component, Bi2O3 component, PoO3 component, Ag2O component, Au2O3 component, PbO component, SnO2 component, WO3 component, MoO3 component, CuO component, Cr2O3 component, MnO component, NiO component, SO3 component, and at least one component selected from PtO2 component.

[0027] The content of each impurity component (for example, oxide) is more than 0% and 2% or less in terms of oxide. When the content of each impurity component is 2% or less, the precipitation of metal components in the crystallized glass, the remaining undissolved metal components, and the resulting non-uniformity of the glass are suppressed, and the crystallized glass is likely to exhibit a good appearance with smoothness and a smooth luster, and it is likely to maintain the same color tone and appearance as glass that does not contain the oxides of the impurity components.In addition, when the crystallized glass is melted, a homogeneous melt is likely to be obtained. The content of each oxide of the impurity component may be 1.8% or less, 1.6% or less, 1.4% or less, 1.2% or less, or 1.0% or less.

[0028] The total amount of impurity components in the crystallized glass is not particularly limited, but may be, for example, 15% or less, 12% or less, 10% or less, 8% or less, 6% or less, 5% or less, or 3% or less in terms of oxide.

[0029] The above-mentioned impurity components (e.g., oxides) have a common function of forming metal colloids and coloring the glass-ceramics. Furthermore, these components have low bonding strength within the glass and act to break the glass network structure, which can significantly reduce viscosity and worsen devitrification, thereby impairing meltability. Among the impurity components, components containing Cr, Mn, Ni, V, and Pd (for example, oxides) have a common effect of coloring the glass-ceramics due to absorption caused by dd transitions. Among the impurity components, components containing Cu, Ag, Pb, and Bi (for example, oxides) have a common effect of coloring the glass-ceramics in the ultraviolet region due to absorption caused by ds, dp, and sp transitions. Among the impurity elements, Ge, As, Sb, and V act to form a network structure in the glass, but their network-forming ability is not high by themselves, and if their content increases, devitrification may worsen and meltability may be impaired. Among the impurity elements, Ga, Te, Sb, Mo, and W can form a glass network structure when coexisting with Si, B, and P, but if their content is too high, devitrification can worsen, thereby impairing meltability.

[0030] The crystallized glass can contain 0.01% to 3.0% (preferably 0.02% to 2.0%, and more preferably 0.05% to 1.0%) of a CeO2 component.

[0031] The amounts of the above components can be combined as appropriate.

[0032] The composition may contain one or more selected from the group consisting of an SiO2 component, an Al2O3 component, a Na2O component, an MgO component, and a ZnO component, a TiO2 component, an Fe2O3 component, and a CoO+Co3O4 component in a total amount of 90% or more, 95% or more, 98% or more, or 98.5% or more.

[0033] The crystallized glass may or may not contain B2O3, P2O5, BaO, Li2O, SrO, and La2O3 components, as long as the effects of the present invention are not impaired. The content of each of these components may be 0% to 2.0%, 0% or more but less than 2.0%, or 0% to 1.0%.

[0034] In addition to CeO2, glass ceramics also contains F and NO as fining agents. x However, the upper limit of the content of the fining agent is preferably 5.0%, more preferably 2.0%, and most preferably 1.0%. x (x is 3, etc.) is preferably not contained since it is unstable in oxidation and reduction and may have an adverse effect on coloring.

[0035] The crystallized glass may or may not contain other components not mentioned above, as long as the properties of the strengthened crystallized glass of the present invention are not impaired. For example, metal components such as Gd, Yb, Lu, etc. (including oxides of these metals).

[0036] <Various physical properties> (chromaticity) The crystallized glass may have a* in the range of -0.10 to 0.12, b* in the range of -2.00 to 0.10, and L* in the range of 20.0 to 30.0 in the CIELAB color space coordinates determined from a reflectance spectrum including specular reflection measured with a spectrophotometer under the following conditions using CIE illuminant D65 at an observer angle of 10°. When a*, b*, and L* are within the above ranges, the glass-ceramics exhibits a good black color with high light-blocking properties. (Reflection spectrum measurement conditions) Sample thickness: 4 mm Light receiving angle relative to the normal to the sample surface: 8° a*, b*, and L* are measured by the method described in the examples.

[0037] a* may be −0.08 to 1.10, or may be −0.06 to 1.00. b* may be from −1.50 to 0.05, or from −1.00 to 0.00. L* may be 22.0 to 29.0, or may be 23.0 to 28.0.

[0038] (Light transmittance) The crystallized glass may have a light transmittance including reflection loss at a thickness of 1 mm of 0.20% or less, 0.15% or less, or 0.10% or less in the wavelength range of 300 nm to 700 nm. When the light transmittance is within the above range, the crystallized glass can exhibit high light-blocking properties.

[0039] (Vickers hardness (Hv)) The crystallized glass may have a Vickers hardness of 550 or more, 580 or more, or 600 or more. High Vickers hardness has the advantages of being excellent in resistance to external shocks and being less susceptible to scratches. There is no particular upper limit to the Vickers hardness, but it is, for example, 900 or less. The Vickers hardness is measured by the method described in the examples.

[0040] (Manufacturing method) The crystallized glass according to one embodiment of the present invention can be produced by the following method: the raw materials are uniformly mixed so that the respective components fall within the predetermined content ranges, and the mixture is melt-molded to produce a base glass. The base glass is then crystallized to produce the crystallized glass. The raw glass material may be, for example, glass members recovered from used electronic devices or the like.

[0041] The raw glass is heat-treated to precipitate crystals inside the glass. The heat treatment can be done in one step or two steps. In the two-stage heat treatment, a nucleation step is first performed by heat treatment at a first temperature, and after this nucleation step, a crystal growth step is performed by heat treatment at a second temperature higher than that of the nucleation step. The first temperature of the two-stage heat treatment is preferably 600° C. to 750° C. The holding time at the first temperature is preferably 30 minutes to 2000 minutes, more preferably 180 minutes to 1440 minutes. The second temperature of the two-stage heat treatment is preferably 650° C. to 850° C. The holding time at the second temperature is preferably 30 minutes to 600 minutes, more preferably 60 minutes to 300 minutes.

[0042] In one-stage heat treatment, the nucleation process and the crystal growth process are carried out consecutively at a single temperature. Typically, the temperature is raised to a predetermined heat treatment temperature, and after reaching that temperature, the temperature is maintained for a certain period of time, and then the temperature is lowered. When heat treatment is performed at one temperature step, the heat treatment temperature is preferably 600 to 800° C., more preferably 630 to 770° C. The holding time at the heat treatment temperature is preferably 30 to 500 minutes, more preferably 60 to 400 minutes.

[0043] A molded body may be produced from the crystallized glass by, for example, grinding and polishing, and then processed into a thin plate. The molded body processed into a thin plate may then be formed into a shape suitable for use as a housing or the like.

[0044] (Strengthening method) The crystallized glass may be strengthened by various strengthening methods to form a compressive stress layer on the surface.

[0045] One method for strengthening crystallized glass to form a compressive stress layer on the surface is chemical strengthening, in which an alkali component present in the surface layer of the crystallized glass is subjected to an exchange reaction with an alkali component having a larger ionic radius, thereby forming a compressive stress layer on the surface layer.

[0046] The chemical strengthening method can be carried out, for example, by the following steps: Crystallized glass is brought into contact with or immersed in a molten salt of a salt containing potassium or sodium, such as potassium nitrate (KNO), sodium nitrate (NaNO), or a mixed salt or composite salt thereof. This treatment of bringing the glass into contact with or immersing it in a molten salt (chemical strengthening treatment) may be carried out in one step or two steps.

[0047] The strengthening method for the crystallized glass is not limited to chemical strengthening, and may be, for example, thermal strengthening or ion implantation.

[0048] [Application] The crystallized glass according to one embodiment of the present invention can be suitably used as components for various devices such as portable electronic devices such as smartphones and tablet PCs, optical devices, construction components, automotive components, etc., and can be suitably used as housings for various devices such as portable electronic devices and optical devices.

[0049] The crystallized glass according to one embodiment of the present invention can be crystallized glass that is recovered from equipment or the like that has components using crystallized glass when the equipment or the like has been used, and is produced as a recycled product (regenerated product) by heating and melting it and re-forming it. The crystallized glass according to one embodiment of the present invention can exhibit a good appearance as a glass even if it is a recycled product (recycled product), so it is suitable for use as a recycled product (recycled product).In addition, since a homogeneous melt is easily obtained when melted, it is also useful when the crystallized glass is used as a raw material to regenerate glass (recycle). The method for recycling crystallized glass according to one aspect of the present invention comprises recovering the crystallized glass according to one aspect of the present invention (including strengthened crystallized glass) from a product containing the crystallized glass, heating and melting the crystallized glass, and crystallizing the crystallized glass. The method for melting and crystallizing the crystallized glass according to one aspect of the present invention can be directly applied to the method described above for the crystallized glass according to one aspect of the present invention. [Example]

[0050] Examples 1 to 6, Comparative Examples 1 to 3 (1) Preparation of raw materials As raw materials for each component of the crystallized glass, raw materials such as oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, metaphosphate compounds, etc. were selected, and these raw materials were weighed and uniformly mixed to obtain the composition shown in Table 1.

[0051] (2) Manufacturing of crystallized glass Next, the mixed raw materials were placed in a platinum crucible and melted in an electric furnace at 1400°C to 1500°C for 4 to 24 hours depending on the melting difficulty of the glass composition. The molten glass was stirred to homogenize it, and after lowering the temperature, it was poured into a mold and slowly cooled to produce base glass. The obtained base glass was crystallized by heat treatment at the temperature and time shown in Table 1. The crystallized glass was crushed to obtain crushed glass. To this pulverized glass, oxides (CuO, Cr2O3, MnO, or NiO) containing the impurity elements shown in Table 1 were added in amounts to give the concentrations shown in Table 1, and the mixture was melted in an electric furnace at 1400°C to 1500°C for 4 to 24 hours. Thereafter, stirring, homogenization, slow cooling, and heat treatment were carried out under the same conditions as above to produce crystallized glass. (3) Vickers hardness Hv of crystallized glass The load when making pyramidal indentations on the surface of multiple Vickers hardness test samples taken from crystallized glass using a diamond pyramidal indenter with a facing angle of 136° was calculated based on the surface area (mm 2 The Vickers hardness was calculated by dividing the hardness by 1 / 2 and the average value was taken as the Vickers hardness. Measurements were carried out using a micro Vickers hardness tester HMV-G21D manufactured by Shimadzu Corporation, with a test load of 200 gf and a holding time of 10 seconds. The Vickers hardness of the crystallized glass is shown in Table 1. In addition, the crystallized glass of Comparative Example 3 had an uneven overall appearance, with black lumpy parts scattered throughout the brown matrix, so the Vickers hardness was measured separately for both the matrix part (brown) and the lumpy parts (black). In Table 1, the upper row shows the Vickers hardness of the matrix part (brown), and the lower row shows the Vickers hardness of the lumpy parts (black).

[0052] (4) Chromaticity The crystallized glass was measured with a 4mm thick sample using a spectrophotometer (Konica Minolta, CM-26dG) to measure the reflectance spectrum, including specular reflection, at an 8° angle relative to the normal to the sample surface. From the obtained reflectance spectrum, the chromaticity L*, a*, and b* (white background) were calculated using CIE illuminant D65 at an observer angle of 10°. The chromaticity L*, a*, and b* of the crystallized glass are shown in Table 1.

[0053] (5) Confirmation of the crystalline phase The crystallized glasses of Examples 1 to 6 were analyzed by EDX and confirmed to be composed of granular crystalline phases of oxides composed of Si, Al, Ti, Mg, and Fe. These are believed to be composed of one or more selected from the group consisting of MgSiO3 or a solid solution thereof, MgAl2SiO8 or a solid solution thereof, SiO2 or a solid solution thereof, MgAl2O4 or a solid solution thereof, MgTi2O4 or a solid solution thereof, Mg2TiO5 or a solid solution thereof, Mg2SiO4 or a solid solution thereof, and FeAl2O4 or a solid solution thereof.

[0054] (6) Meltability The obtained crystallized glass was melted at 1400°C to 1500°C for 24 hours, and the state of the melted glass was visually observed and evaluated according to the following criteria. A: There was no devitrification, unmelted material, or precipitates during melting, and the melt became homogeneous. B: The melt was devitrified during melting, or unmelted material or precipitates were generated, and the melt was not homogeneous.

[0055] (7) Appearance The appearance of the resulting crystallized glass was visually observed and evaluated according to the following criteria. A: Both the surface and the interior of the crystallized glass were black, with no other colors observed, and it had a smooth and glossy appearance. B: A color other than black was observed on at least one of the surface and the interior of the crystallized glass, or the glass did not have a smooth and glossy appearance. The crystallized glass obtained in Comparative Example 1 had a black surface and a reddish-brown interior, the crystallized glass obtained in Comparative Example 2 had a black surface and an ochre interior, and the crystallized glass obtained in Comparative Example 3 had a black surface and a mixture of ochre and brown interior. These lacked smoothness and luster, and did not have a good appearance as glass.

[0056] (8)XRD measurement For each of the base glasses (prepared by adding impurity components) of Example 6, Comparative Example 1, and Comparative Example 2, XRD measurements were carried out by the following method to obtain XRD spectra. The results are shown in FIG. 1, (a) shows the XRD spectrum of the base glass of Example 6, (b) shows the XRD spectrum of the base glass of Comparative Example 1, and (c) shows the XRD spectrum of the base glass of Comparative Example 2. 1, it can be seen that in (b) Comparative Example 1 and (c) Comparative Example 2, undesired crystals were precipitated at the raw glass stage. As shown in (7) Appearance Evaluation, the glasses obtained in Comparative Examples 1 and 2 had different color shades on the surface and inside, and could not be said to be high-quality glasses. The results of the XRD measurement supported the results of the appearance evaluation. (XRD measurement conditions) The XRD spectrum of the raw glass was measured using an X-ray diffraction analyzer (D8Discover, manufactured by Bruker), and the halo characteristic of glass and peaks characteristic of crystals were observed from the XRD spectrum.

[0057] [Table 1]

[0058] From Table 1, it can be seen that the crystallized glass of the present invention having a specific composition exhibits a smooth, glossy, and excellent appearance, despite containing impurity components. On the other hand, the glasses obtained in Comparative Examples 1 to 3 had an uneven overall appearance, lost their smoothness and smooth gloss, and were significantly inferior to the crystallized glass of the present invention. Furthermore, the crystallized glasses obtained in Examples 1 to 6 were found to be homogeneous melts when melted, which indicates that they are easily recycled as raw materials. On the other hand, the glasses obtained in Comparative Examples 1 to 3 were found to produce unmelted material when melted, which indicates that they are difficult materials to recycle.

Claims

1. In terms of oxide, mass % SiO ２ Ingredients: 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Ingredients: 0.5 to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO+Co ３ O ４ Ingredients: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４ Ingredients greater than 0% to 19.0%, and a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, the content of each of these elements, when present, being more than 0% and not more than 2%; Crystallized glass.

2. In terms of oxide, mass % K ２ O component 0% to 9.0%, 1.0% to 20.0% of one or more selected from the group consisting of MgO and ZnO, and 2. The crystallized glass according to claim 1, containing 0% to 3.0% of a CaO component.

3. In terms of oxide, mass % TiO ２ Ingredients: 4.0% to 10.0%, Fe ２ O ３ Component 2.0% to 12.0%, and CoO component and Co ３ O ４ 3. The crystallized glass according to claim 1, which contains 0.05% to 0.5% of one or more components selected from the following:

4. In terms of oxide, mass % SiO ２ Ingredients: 45.0% to 65.0%, Al ２ O ３ Ingredients: 13.0% to 23.0%, Na ２ O component 8.0% to 16.0%, K ２ O component 0.1% to 9.0%, 2.0% to 20.0% of one or more selected from the group consisting of MgO and ZnO; 3. The crystallized glass according to claim 1, containing 0.01% to 3.0% of a CaO component.

5. 3. The crystallized glass according to claim 1, having a Vickers hardness of 550 or more.

6. The crystallized glass according to claim 1 or 2, wherein a1* is in the range of -0.10 to 0.12, b1* is in the range of -2.00 to 0.10, and L1* is in the range of 20.0 to 30.0 in the CIELAB color space coordinates, which are obtained from the reflectance spectrum including regular reflection measured by a spectrophotometer under the following conditions and using CIE illuminant D65 at an observer angle of 10°. (Reflection spectrum measurement conditions) Sample thickness: 4 mm Light receiving angle relative to the normal to the sample surface: 8°

7. In terms of oxide, mass % SiO ２ Ingredients: 40.0% to 70.0%, Al ２ O ３ Ingredients: 11.0% to 25.0%, Na ２ O component 3.0% to 19.0%, TiO ２ Ingredients: 0.5 to 12.0%, Fe ２ O ３ Ingredients: 0% to 15.0%, CoO+Co ３ O ４ Ingredients: 0% to 4.0%, Fe ２ O ３ + CoO + Co ３ O ４ Ingredients greater than 0% to 19.0%, and A method for recycling crystallized glass, comprising heating and melting crystallized glass containing a component containing at least one element selected from V, Ga, As, Ge, Se, Y, Zr, Nb, Ru, Rh, Pd, Cd, In, Sb, Te, Hf, Ta, W, Re, Os, Ir, Hg, Tl, Bi, Po, Ag, Au, Pb, Sn, Mo, Cu, Cr, Mn, Ni, S, and Pt, each of which is present in an amount of more than 0% and not more than 2%.

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