Reducing agent for glass, method for producing fine metal particle-containing glass, fine metal particle-containing glass, and method for recycling glass

Abstract

By using a reducing agent for glass according to the present invention, unnecessary substances and unnecessary components can be appropriately and quickly removed from glass containing foreign matter and the like, or glass containing coloring components or unnecessary components. The present invention relates to a reducing agent for glass, the reducing agent containing SiC.

Description

Reducing agent for glass, method for producing glass containing metal fine particles, glass containing metal fine particles, and method for recycling glass

[0001] The present invention relates to a reducing agent for glass, a method for producing glass containing metal fine particles using the reducing agent for glass, glass containing metal fine particles, and a method for recycling glass.

[0002] Recycling glass products is desirable from the perspective of resource circulation and greenhouse gas reduction. However, currently, most discarded glass products and some of the defective glass generated in intermediate processes are discarded without being recycled.

[0003] The reasons for this include, for example, the following: (1) When glass containing foreign matter such as metals, ceramics, or organic matter (hereinafter also referred to as external foreign matter) is placed into a melting furnace, various manufacturing defects occur, making it difficult to recycle it into glass. (2) Colored glass exists in a variety of colors, and it is difficult to collect them individually. Therefore, once mixed together, it is difficult to recycle it horizontally into the same colored glass as before recycling. (3) Solar panel (hereinafter also referred to as PV panel) glass contains Sb, and therefore becomes colored in the float bath, making it difficult to recycle it into plate glass using the float method.

[0004] That is, when waste glass or defective glass contains foreign matter or contains coloring components or unnecessary components in the glass, even if glass is produced using this as a raw material, the resulting glass may have manufacturing defects or unnecessary coloring.

[0005] In response to this, for example, Non-Patent Document 1 describes a method for removing the Fe component, which is a coloring component in glass, by utilizing the phase separation phenomenon of alkali-containing borosilicate glass.

[0006] Takuya Imaoka and three others, "Material recycling of molten slag from municipal waste using phase separation of glass", Research Report of the Faculty of Environmental Science and Technology, Okayama University, 12(1), (2007) 161-165.

[0007] However, when coloring components and the like in glass are removed by utilizing the phase separation phenomenon as described in Non-Patent Document 1, the process becomes complicated and may be less efficient. In addition, useful components such as alkali metal components are also removed at the same time.

[0008] In view of the above, an object of the present invention is to provide a reducing agent for glass that can appropriately and quickly remove external foreign matter, coloring components, or unnecessary components from glass containing external foreign matter, etc., or glass containing coloring components or unnecessary components; a method for producing glass containing metal fine particles using the reducing agent for glass; glass containing metal fine particles; and a method for recycling glass.

[0009] That is, the present invention relates to the following [1] to

[25] . [1] A reducing agent for glass containing SiC. [2] The reducing agent for glass according to [1], which has interconnected pores. [3] The reducing agent for glass according to [1] or [2], which contains a mixture or composite of SiC and C. [4] The reducing agent for glass according to [1] or [2], in which the volume ratio of SiC to the entire reducing agent is 0.01 to 1. [5] A reducing agent for glass having a bulk density of 0.55 to 1.50 g / cm ３ , apparent density is 1.60 to 3.00 g / cm ３ , true density is 2.15 to 3.50 g / cm ３The reducing agent for glass according to [1] or [2], having a porosity of 5 to 50% and a filling rate of 40 to 80%. [6] The reducing agent for glass according to [1] or [2], which is in the form of chunks or broken pieces and has a size of 1 to 100 mm. [7] The reducing agent for glass according to [1] or [2], which acts by contacting with a molten material obtained by melting a glass-containing raw material. [8] The reducing agent for glass according to [7], wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components. [9] A method for producing metal fine particle-containing glass containing metal fine particles, comprising: melting a glass-containing raw material containing glass to obtain a molten material; and reducing the molten material using the reducing agent for glass according to [1] or [2].

[10] The method for producing metal fine particle-containing glass according to [9], wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components.

[11] The method for producing metal fine particle-containing glass according to [9], wherein the treatment temperature in the reduction treatment is 1300°C to 1800°C.

[12] The method for producing metal fine particle-containing glass according to [9], wherein the number density of the metal fine particles for each particle size in an arbitrary cross section of the metal fine particle-containing glass is in the following range, and the area ratio occupied by the metal fine particles in the arbitrary cross section is 0 to 0.10% with respect to the total area. Particle size more than 1 μm and 5 μm or less: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２

[13] The metal fine particle-containing glass has a visible light transmittance Tv at a thickness of 2 mm and a transmittance T at a wavelength of 1100 nm. １１００ The absolute value of the difference ABS (Tv-T １１００

[14] The method for producing metal fine particle-containing glass according to [9], wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb.

[15] The method for producing metal fine particle-containing glass according to [9], wherein the total content NWF of network forming oxides contained in the glass-containing raw material is, in terms of mass % on an oxide basis, ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total NWM of the contents of network modifier oxides contained in the glass-containing raw material is ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ

[16] The method for producing metal fine particle-containing glass according to [9], wherein the average Fe in the metal fine particle-containing glass is 0.60 to 2.00. ２ O ３

[17] A method for producing metal fine particle-containing glass according to [9], wherein the concentration is 0.001% to 0.5% in terms of mass % on an oxide basis.

[17] A glass containing metal fine particles, wherein the number density of the metal fine particles for each particle size in an arbitrary cross section is in the following range, and the area ratio of the metal fine particles in the arbitrary cross section to the total area is 0 to 0.10%. Particle size more than 1 μm and 5 μm or less: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２

[18] The metal fine particle-containing glass according to

[17] , which is obtained by melting a glass-containing raw material and reducing the resulting molten material with a reducing agent for glass containing SiC.

[19] The metal fine particle-containing glass according to

[17] , wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components.

[20] The metal fine particle-containing glass according to

[17] , wherein the visible light transmittance Tv at a thickness of 2 mm and the transmittance T at a wavelength of 1100 nm are １１００ The absolute value of the difference ABS (Tv-T １１００

[21] The metal fine particle-containing glass according to

[17] or

[18] , wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb.

[22] The total content NWF of network-forming oxides contained in the glass-containing raw material, calculated as mass % on an oxide basis, is ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total content NWM of network modifier oxides contained in the glass-containing raw material ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ

[23] The metal fine particle-containing glass according to

[17] or

[18] , wherein the average Fe in the metal fine particle-containing glass is 0.60 to 2.00. ２ O ３The metal fine particle-containing glass according to

[17] or

[18] , having a concentration of 0.001% to 0.5% expressed in mass % on an oxide basis.

[24] A method for recycling glass, comprising: melting a glass-containing raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components to obtain a molten material; and subjecting the molten material to a reduction treatment using the reducing agent for glass according to [1] or [2].

[25] The method for recycling glass according to

[24] , further comprising subjecting the molten material to an oxidation treatment.

[0010] By using the reducing agent for glass of the present invention, it is possible to appropriately and quickly remove unnecessary substances and components from glass containing foreign matter, etc., or glass containing colored components or unnecessary components. In other words, by using the reducing agent for glass of the present invention, it is possible to suitably recycle various waste glass products, defective glass, etc. containing unnecessary substances and unnecessary components.

[0011] Fig. 1A is a diagram showing an example of an image of metal-microparticle-containing glass obtained by the method for producing metal-microparticle-containing glass according to this embodiment, taken at 200x magnification using a predetermined method. Fig. 1B is a diagram showing an image of Fig. 1A after image processing. Fig. 2A is a diagram showing an example of an image of metal-microparticle-containing glass obtained by the method for producing metal-microparticle-containing glass according to this embodiment, taken at 1000x magnification using a predetermined method. Fig. 2B is a diagram showing an image of Fig. 2A after image processing.

[0012] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified as desired without departing from the gist of the present invention. In this specification, the term "to" indicating a numerical range is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, in this specification, ratios, proportions, etc. based on mass are synonymous with ratios, proportions, etc. based on weight.

[0013] [Reducing Agent for Glass] A reducing agent for glass according to an embodiment of the present invention (hereinafter also referred to as the present reducing agent for glass) contains SiC. The reducing agent for glass acts by contacting with a molten material obtained by melting a glass-containing raw material. The inventors have found that SiC has good wettability with glass melt, and therefore, it is possible to reduce CO and CO generated by the reaction between the glass melt and the reducing agent. ２ It has been found that gases such as SiO2 and SiO2 are rapidly released from the interface between the glass and the reducing agent, allowing the reduction reaction to proceed without being hindered by the gas phase. In other words, by including SiC in the reducing agent for glass, it is possible to carry out the reduction treatment of glass appropriately and quickly. Examples of SiC include recrystallized SiC, single crystal SiC, and SiO2. ２ and Si ３ N ４ Examples include sintered SiC to which an auxiliary agent such as SiO2 or the like has been added, and recrystallized SiC is preferred from the viewpoints of availability, price, and high purity of the SiC component.

[0014] The reducing agent for glass may be formed only of SiC, or may contain compounds other than SiC. Examples of compounds other than SiC include simple substances and compounds containing one or more elements selected from the group consisting of C, Al, Si, Ca, Ti, and H. Specific examples include C, Al, Si, Ca, Ti, and H. ２ , CO, Fe-Si alloy, Ca-Si alloy, CH ４ , N.H. ３ and the like. One or more compounds other than SiC may be contained. Furthermore, the compound may be contained as a mixture with SiC or as a composite. In this specification, a composite of SiC and a compound other than SiC means that at least a portion of the SiC and the compound other than SiC are physically or chemically bonded to form a single mass.

[0015] The reducing agent for glass according to the embodiment of the present invention preferably contains a mixture or composite of SiC and C from the viewpoint of improving the efficiency of the reduction treatment. ２ Along with the gas, SiO ２ Generates SiO ２When dissolved in glass, it increases the viscosity of the glass, and the reaction efficiency decreases if the reaction continues for a long time. However, when the glass reducing agent contains a mixture or composite of SiC and C, SiO ２ It is presumed that the efficiency of the reduction treatment is improved because the generation and reactivity of

[0016] In the reducing agent for glass according to the embodiment of the present invention, the volume ratio of SiC to the entire reducing agent is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, and particularly preferably 0.2 or more. Furthermore, the volume ratio of SiC to the entire reducing agent is 1 or less, preferably 0.8 or less, and more preferably 0.6 or less. In the reducing agent for glass according to the embodiment of the present invention, the volume ratio of SiC to the entire reducing agent is preferably 0.01 to 1, more preferably 0.05 to 0.8, and even more preferably 0.1 to 0.6.

[0017] The reducing agent for glass according to the embodiment of the present invention preferably reduces glass by contacting a glass melt with the reducing agent for glass. Through investigations by the present inventors, it has been found that by using SiC as at least a part of the reducing agent for glass, the wettability between the glass and the reducing agent is improved and the reduction reaction is accelerated compared to when C is used alone. This is because CO gas and CO generated when the glass reacts with the reducing agent are not easily absorbed. ２ In the reducing agent for glass according to the embodiment of the present invention, SiC may be used alone, but in order to prevent the wettability with glass from becoming too good and to suppress a decrease in the efficiency of separation of the glass and the reducing agent for glass, the volume ratio of SiC to the entire reducing agent for glass is preferably 0.8 or less.

[0018] The state of the glass reducing agent is preferably solid at room temperature for ease of handling. Its shape is not particularly limited, but may be, for example, granular, powdery, lumpy, plate-like, crushed, or a molded body processed into a desired shape. From the viewpoint of ease of handling and availability, it is more preferably in the form of lumps or crushed pieces. Alternatively, for example, it may be a lumpy C whose surface is at least partially coated with SiC. It may also contain SiC, which is solid at room temperature, and a compound other than SiC that is gaseous or liquid at room temperature. When the compound other than SiC is gaseous, it may be allowed to flow through the gaps in the SiC or through the glass melt. When the compound other than SiC is liquid, it may be added together with the glass-containing raw material.

[0019] The size of the reducing agent for glass is preferably 1 to 100 mm, more preferably 2 to 80 mm, from the viewpoint of improving the efficiency of the reduction treatment. When the reducing agent for glass is a mixture or composite, the size of the reducing agent that accounts for 80% or more of the entire reducing agent by mass is preferably 1 to 100 mm, more preferably 2 to 80 mm, from the viewpoint of improving the efficiency of the reduction treatment. In particular, in the method for producing glass containing metal microparticles described below, when the glass-containing raw material is melted in a container in which the reducing agent is previously placed, this allows the size of the voids between the reducing agents to be appropriate, thereby enabling the entire melt to be efficiently reduced. The size of the reducing agent for glass can be evaluated by passing it through a sieve with a predetermined mesh size. Note that the preferred range does not include small reducing agents that are generated by collisions between reducing agents during addition or transportation, or by reaction with the melt in the method for producing glass containing metal microparticles described below.

[0020] The reducing agent for glass according to the embodiment of the present invention is preferably in the form of a lump or crushed pieces, with a size of 1 to 100 mm.

[0021] The reducing agent for glass according to the embodiment of the present invention preferably has interconnected pores from the viewpoint of improving the efficiency of the reduction treatment. When the reducing agent for glass is brought into contact with a molten material obtained by melting a glass-containing raw material, CO and CO are generated at the contact interface. ２When the reducing agent for glass has interconnected pores, the bubbles generated at the contact interface can be easily removed from the contact interface, which is thought to improve the efficiency of the reduction treatment.

[0022] The presence or absence of interconnected pores in the reducing agent for glass can be confirmed, for example, by embedding the reducing agent in a two-component curing epoxy resin, placing it in a vacuum chamber, and reducing the pressure inside the chamber to 0.1 atmospheres or less using a vacuum pump to remove any air bubbles inside the resin. After the resin has hardened, a cross-section is taken and it is observed whether the resin has penetrated the inside.

[0023] The reducing agent for glass according to an embodiment of the present invention has a bulk density of 0.55 to 1.50 g / cm ３ is preferably 0.58 to 1.35 g / cm ３ More preferably, it is 0.61 to 1.20 g / cm ３ It is more preferable that the bulk density is 1.50 g / cm ３ If the bulk density is 0.55 g / cm or less, an escape route for the glass melt and the gas generated in the reduction reaction can be secured, and the reduction treatment efficiency is excellent. ３ If the density is above 100%, a sufficient contact area with the glass melt can be secured, resulting in excellent reduction treatment efficiency. The bulk density can be measured by the container method. The bulk density is loose bulk density, and it has been confirmed that within the scope of the present invention, there is almost no difference between the loose bulk density and the packed bulk density.

[0024] The reducing agent for glass according to an embodiment of the present invention has a true density of 2.12 to 3.50 g / cm ３ is preferably 2.15 to 3.20 g / cm ３ More preferably, it is 2.20 to 3.00 g / cm ３ It is more preferable that the true density is 3.50 g / cm ３ If the true density is 2.12 g / cm or less, the glass is prevented from settling in a sinking state when mixed with the glass melt, and fluctuations due to the flow of the melt and the generation of gas are likely to occur, resulting in excellent reduction treatment efficiency. ３If the density is equal to or greater than this, the reducing agent will not float easily when mixed with the glass melt, reducing the contact area and preventing a decrease in the efficiency of the reduction treatment. The true density can be measured by the submerged weighing method. When the glass reducing agent is a mixture of two or more compounds, the true density is calculated as a weighted average, i.e., the sum of the products of the true densities and volume ratios of the respective compounds. For example, the true density of a mixture of compound X and compound Y can be calculated using the following formula (A): True density of mixture = {(true density of compound X) x (volume ratio of compound X) + (true density of compound Y) x (volume ratio of compound Y)} (A)

[0025] The glass reducing agent according to the embodiment of the present invention preferably has a porosity of 5 to 50%, more preferably 10 to 40%, and even more preferably 15 to 30%. A porosity of 50% or less ensures sufficient strength of the reducing agent and makes it less susceptible to collapse. This prevents the reducing agent from collapsing and generating a large amount of fine powder, and also prevents the glass melt from separating from the reducing agent. Furthermore, a porosity of 5% or more allows gas generated during the reduction reaction to escape easily, resulting in excellent reduction treatment efficiency. Porosity can be measured by mercury intrusion porosimetry. When the glass reducing agent is a mixture of two or more compounds, the porosity is calculated as a weighted average, i.e., the sum of the products of the porosities and volume ratios of the individual compounds.

[0026] The reducing agent for glass according to an embodiment of the present invention has an apparent density of 1.60 to 3.00 g / cm ３ is preferably 1.62 to 2.80 g / cm ３ More preferably, it is 1.65 to 2.60 g / cm ３ It is more preferable that the apparent density is 3.00 g / cm ３ If the apparent density is 1.60 g / cm or less, the glass is prevented from settling in a sinking state when mixed with the glass melt, and fluctuations due to the flow of the melt and the generation of gas are likely to occur, resulting in excellent reduction treatment efficiency. ３If the density is equal to or greater than this, the glass will not float easily when mixed with the glass melt, and the contact area will decrease, preventing a decrease in the efficiency of the reduction treatment. The apparent density can be calculated from the above-mentioned true density and porosity using the following formula (B): apparent density = true density × (100 - porosity) / 100 (B)

[0027] The reducing agent for glass according to the embodiment of the present invention preferably has a packing ratio of 40 to 80%, more preferably 41 to 65%, and even more preferably 42 to 55%. If the packing ratio is 80% or less, a sufficient flow path diameter between the reducing agents is obtained, allowing the glass melt and gas generated during the reduction reaction to easily escape, resulting in excellent reduction treatment efficiency. Furthermore, if the packing ratio is 40% or more, a sufficient contact area with the glass melt is obtained, preventing a decrease in reduction treatment efficiency. The packing ratio can be calculated using the bulk density and apparent density described above according to the following formula (C): Packing ratio = (bulk density / apparent density) × 100 (C)

[0028] The reducing agent for glass according to the embodiment of the present invention has a bulk density of 0.55 to 1.50 g / cm from the viewpoint of improving the efficiency of the reduction treatment. ３ , apparent density is 1.60 to 3.00 g / cm ３ , true density is 2.15 to 3.50 g / cm ３ It is preferable that the porosity is 5 to 50% and the filling rate is 40 to 80%.

[0029] The reducing agent for glass according to the embodiment of the present invention preferably has a median pore diameter of 3 to 50 μm, more preferably 5 to 40 μm, and even more preferably 10 to 35 μm. The median pore diameter can be measured by mercury intrusion porosimetry or BET method. If the median pore diameter is 50 μm or less, the reducing agent has sufficient strength and is less likely to collapse. This prevents the reducing agent from collapsing and generating a large amount of fine powder, and prevents the glass melt from becoming difficult to separate from the reducing agent. Furthermore, if the median pore diameter is 3 μm or more, gas generated during the reduction reaction can easily escape, resulting in excellent reduction treatment efficiency.

[0030] [Method for manufacturing metal microparticle-containing glass] A method for manufacturing metal microparticle-containing glass according to an embodiment of the present invention (hereinafter also referred to as the present manufacturing method) will be described. The present manufacturing method includes melting a glass-containing raw material containing glass to obtain a molten material, and reducing the molten material using the above-mentioned reducing agent for the present glass. More specifically, this method includes, for example, the following steps (i) to (iii).

[0031] Step (i): melting a glass-containing raw material to obtain a first melt; Step (ii): reducing the first melt using the reducing agent for glass of the present disclosure to generate a metal phase; Step (iii): separating at least a portion of the metal phase from the first melt to obtain a second melt.

[0032] As will be described in detail later, the glass-containing raw material is, for example, a raw material containing glass containing foreign matter, glass containing coloring components or unnecessary components, etc. That is, the glass-containing raw material may be a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components. The present inventors have found that, when a melt of glass containing foreign matter or glass containing coloring components or unnecessary components is subjected to a reduction treatment using the reducing agent for this glass, impurity elements derived from the foreign matter, coloring components, or unnecessary components can be generated as a metal phase and separated from the melt, and that the reduction treatment has excellent treatment efficiency.

[0033] [Step (i)] In step (i), a glass-containing raw material is melted to obtain a first molten material. (Glass-containing raw material) The glass-containing raw material is not particularly limited, but examples thereof include raw materials containing glass containing foreign matter, glass containing coloring components or unnecessary components, etc.

[0034] Examples of glass containing foreign matter include a mixture containing glass and a substance other than glass, a mixture of glasses with different main compositions, and a composite in which a substance other than glass is attached or bonded to glass. Here, the main composition means the composition of the main oxides that make up the glass, and specifically, for example, SiO ２ , Al ２ O ３ , B２ O ３ , P ２ O ５ The term "foreign matter" refers to a composition of a network-forming oxide such as a metal oxide, or a network-modifying oxide such as an alkaline earth metal oxide or an alkali metal oxide. Examples of foreign matter include, but are not limited to, metals, ceramics, organic materials, and composite materials composed of organic and inorganic materials. Representative examples of each are listed below. Metals include cast iron, stainless steel, aluminum, copper, silver, silicon, lead, zinc, tin, solder, and heat wire (mainly composed of Ag) applied to automotive window glass. Ceramics include concrete, cement, ceramics, heat-resistant boards, black ceramic prints (commonly known as "black ceramic") applied to automotive window glass, and desiccants such as zeolite used in double-glazed glass. Organic materials include sealing materials, interlayer films, paper, wood, plastics, and bottle labels. Composite materials composed of organic and inorganic materials include substrates used in printed circuit boards and fiber-reinforced plastics.

[0035] According to this manufacturing method, impurity elements contained in the first molten material due to these external foreign matters can be efficiently and quickly removed. For example, if the external foreign matter is an organic substance, the impurities derived from it are not necessarily separated as a metal phase in step (ii). However, as described below, according to this manufacturing method, defects derived from organic matters can also be suppressed. First, during the melting process in step (i), the organic matter is burned, and most of it is gasified and removed. On the other hand, some remains in the molten material as a carbon residue and acts as a reducing agent to reduce the glass. If left as is, such carbon residue is thought to lead to the occurrence of defects. However, the degree of reduction by the carbon residue is small in the subsequent reduction treatment step (ii), and its influence can be completely eliminated, for example, by further oxidizing the obtained metal microparticle-containing glass.

[0036] When the glass-containing raw material contains foreign matter, the content of foreign matter in the glass-containing raw material is preferably 0.1 mass ppm or more, more preferably 1 mass ppm or more, and even more preferably 10 mass ppm or more, from the viewpoint of, for example, suitably obtaining the effects of the present invention. On the other hand, the content of foreign matter in the glass-containing raw material is preferably 100,000 mass ppm or less, more preferably 50,000 mass ppm or less, and even more preferably 30,000 mass ppm or less, from the viewpoint of obtaining high-quality glass. That is, the content of foreign matter in the glass-containing raw material is preferably in the range of 0.1 mass ppm to 100,000 mass ppm.

[0037] Examples of impurity elements derived from external foreign matter, coloring components, or unnecessary components include Fe, Co, Cr, Ni, Sb, Zn, Mn, Sn, Bi, Pb, Ag, Cu, W, and Nb. These elements tend to be more easily reduced than the main components of glass. According to this manufacturing method, these impurity elements contained in the first molten material can be preferably removed, thereby suppressing coloration of the resulting glass and obtaining glass with excellent transparency. Hereinafter, the term "impurity element" used in this specification refers to one or more elements selected from the group consisting of Fe, Co, Cr, Ni, Sb, Zn, Mn, Sn, Bi, Pb, Ag, Cu, W, and Nb. The impurity element is preferably one or more elements selected from the group consisting of Fe, Co, Cr, Ni, and Sb.

[0038] When the glass-containing raw material contains the above-mentioned impurity elements, the content thereof preferably satisfies one or more of the following (1) to (14) when the composition of the glass-containing raw material is expressed in mass % or mass ppm based on the oxide. In such cases, the glass-containing raw material can be said to contain a certain amount of impurity elements, making it easier to obtain the effects of the present manufacturing method. In this specification, the composition of the glass-containing raw material refers to the average composition of the entire glass-containing raw material, including cases where the glass-containing raw material is a mixture or composite containing external foreign matter. The composition of the glass-containing raw material can be measured by appropriately selecting the method described in JIS K0050:2019 "General Rules for Chemical Analysis Methods." It is preferable to melt the glass-containing raw material under atmospheric pressure and analyze the resulting composition using X-ray fluorescence analysis (XRF), electron probe microanalyzer (EPMA), ICP optical emission spectroscopy, or ICP mass spectrometry, since this allows the overall average composition to be measured relatively easily. (1) Fe ２ O ３ : 0.001 mass% or more (2) CoO: 1 mass ppm or more (3) Cr ２ O ３ : 1 mass ppm or more (4) NiO: 1 mass ppm or more (5) Sb ２ O ３ : 1 mass ppm or more (6) ZnO: 1 mass ppm or more (7) MnO: 1 mass ppm or more (8) SnO ２ : 1 mass ppm or more (9) Bi ２ O ３ : 1 mass ppm or more (10) PbO: 1 mass ppm or more (11) Ag ２ O: 1 mass ppm or more (12) CuO: 1 mass ppm or more (13) WO ３ : 1 mass ppm or more (14) Nb ２ O ５ :1 mass ppm or more

[0039] In the present manufacturing method, a glass-containing raw material containing a certain amount of impurity elements is suitable, but in consideration of the quality of the glass to be obtained, it is preferable that the content of the impurity elements is not too high. ２ O ３The content of each of the above impurity elements other than Fe is preferably 5 mass% or less, more preferably 3 mass% or less. The content of each of the above impurity elements other than Fe is preferably 10,000 mass ppm or less, more preferably 5,000 mass ppm or less, expressed in mass ppm based on the oxide. For example, when the glass-containing raw material contains the above impurity elements, it is more preferable that the content of the impurity elements satisfies one or more of the following (1)' to (14)', expressed in mass% or mass ppm based on the oxide. (1)'Fe ２ O ３ : 0.001 to 5% by mass (2)'CoO: 1 to 10,000 mass ppm (3)'Cr ２ O ３ : 1 to 10,000 mass ppm (4)'NiO: 1 to 10,000 mass ppm (5)'Sb ２ O ３ : 1 to 10,000 mass ppm (6)'ZnO: 1 to 10,000 mass ppm (7)'MnO: 1 to 10,000 mass ppm (8)'SnO ２ :1~10000 mass ppm (9)'Bi ２ O ３ : 1 to 10,000 mass ppm (10)'PbO: 1 to 10,000 mass ppm (11)'Ag ２ O: 1 to 10,000 mass ppm (12)'CuO: 1 to 10,000 mass ppm (13)'WO ３ :1 to 10000 mass ppm (14)'Nb ２ O ５ :1 to 10000 mass ppm

[0040] Specific examples of the glass-containing raw materials exemplified above include raw materials derived from waste glass products and defective glass generated during the manufacturing process of glass products. If necessary, cullet obtained by processing waste glass products or defective glass, such as by crushing, may be used as the glass-containing raw material. The type of glass product is not particularly limited, but examples include double-glazed glass, laminated glass, printed glass, mirrors, PV panel glass, glass bottles, glass wool, fire-resistant glass, heat-resistant glass, glass used in devices such as smartphones, and glass used in liquid crystal displays. Raw materials derived from such glass products tend to contain external foreign matter, coloring components, or unnecessary components, making them suitable as the glass-containing raw material for the present manufacturing method. Furthermore, using waste glass products or defective glass as the glass-containing raw material allows for glass recycling, which is preferable from the perspective of resource circulation and greenhouse gas reduction. The glass-containing raw material may contain glass raw materials or additives other than waste glass products or defective glass for the purpose of adjusting the composition of the resulting glass or adjusting the viscosity of the melt, as described below.

[0041] From the viewpoint of efficient recycling, the glass-containing raw material preferably contains cullet in an amount of 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0042] (First molten product) The viscosity of the first molten product is preferably 0.1 dPa·s to 100,000 dPa·s at the temperature of step (ii), i.e., the temperature during the reduction treatment. That is, the viscosity is preferably 100,000 dPa·s or less, more preferably 10,000 dPa·s or less, and even more preferably 1,000 dPa·s or less. When the viscosity is equal to or less than the above upper limit, the reduction treatment in step (ii) can be easily carried out. The lower limit of the viscosity is not particularly limited, but is preferably 0.1 dPa·s or more, for example, from the viewpoint of suppressing erosion of the refractory. The viscosity of the first molten product can be measured by the rotating cylinder method, the sphere pulling method, or the like.

[0043] In view of the above, the present production method may further include adjusting the viscosity of the first molten material to 0.1 dPa·s to 10,000 dPa·s. A more preferable range of the viscosity is the same as above. The method for adjusting the viscosity of the first molten material is not particularly limited, and examples thereof include a method of adding a substance capable of adjusting viscosity to the glass-containing raw material or the first molten material. The substance that can be added to the glass-containing raw material or the first molten material is not particularly limited, and examples thereof include carbonates, hydroxides, oxides, fluorides, chlorides, etc. containing alkali metal elements or alkaline earth metal elements when a relatively low viscosity is desired, and oxides, etc. containing silicon, aluminum, boron, phosphorus, etc. when a relatively high viscosity is desired.

[0044] [Step (ii)] In step (ii), the first melt is reduced using a reducing agent for the present glass to produce a metal phase. As the reducing agent in the reduction treatment, the above description of the reducing agent for the present glass can be used as is.

[0045] Specifically, the reduction treatment method may involve contacting the first molten material with a reducing agent. For example, a method of contacting the first molten material with a reducing agent by adding a solid reducing agent to the first molten material, or a method of melting a glass-containing raw material in a container in which a reducing agent has been placed in advance and contacting the resulting first molten material with a reducing agent, etc. The term "container in which a reducing agent has been placed" includes not only a case in which a container has a reducing agent therein, but also a case in which part or all of the container itself acts as a reducing agent. Furthermore, when melting a glass-containing raw material in a container in which a reducing agent has been placed in advance, step (i) and step (ii) are performed in parallel. From the viewpoint of ease of operation, a method of melting a glass-containing raw material in a container in which a reducing agent has been placed in advance is preferred.

[0046] When melting a glass-containing raw material in a container in which a reducing agent has been placed in advance, it is preferable to fill the container with the reducing agent so that the filling rate is 20 to 80 volume % and bring the reducing agent into contact with the first melt. That is, the filling rate is preferably 20 volume % or more, more preferably 30 volume % or more, and even more preferably 40 volume % or more. On the other hand, the filling rate is preferably 80 volume % or less, more preferably 75 volume % or less, and even more preferably 70 volume % or less. This allows the entire melt to be efficiently reduced. The filling rate of the reducing agent can be calculated from the mass of the reducing agent when the reducing agent is filled in a container having a certain volume and the apparent density of the reducing agent.

[0047] The volume ratio of the reducing agent to the first molten material is preferably 0.001 to 100. That is, from the viewpoint of ensuring a sufficient effect of the reduction treatment, the volume ratio is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more. On the other hand, from the viewpoint of space-saving treatment, the volume ratio is preferably 100 or less, more preferably 50 or less, and even more preferably 30 or less. The volume ratio of the reducing agent to the first molten material can be determined by calculation from the average composition and input amount of the melt and the average composition and input amount of the reducing agent. When the glass-containing raw material is melted in a container in which a reducing agent has been placed in advance, the reduction treatment can be performed as long as the reducing agent is not lost due to reaction with an oxidizing gas such as oxygen contained in the melt or in a small amount in the atmosphere.

[0048] The reduction treatment method may be a combination of the above-described method using a reducing agent and a method of electrolyzing the first molten material. When electrolyzing the first molten material, for example, two electrodes are placed in the first molten material and a voltage is applied between them to perform the electrolysis.

[0049] The treatment temperature in the reduction treatment is preferably 1300° C. to 1800° C. That is, from the viewpoint of ensuring a sufficient reduction reaction rate and reducing power, the treatment temperature is preferably 1300° C. or higher, more preferably 1400° C. or higher, and even more preferably 1450° C. or higher. On the other hand, from the viewpoint of suppressing erosion of the refractory and suppressing energy consumption, the treatment temperature is preferably 1800° C. or lower, more preferably 1700° C. or lower, and even more preferably 1650° C. or lower.

[0050] The reduction treatment time is not particularly limited depending on the type of reducing agent, the composition of the first molten material, etc., but is preferably, for example, 10 minutes to 48 hours. That is, from the viewpoint of allowing the reduction reaction to proceed sufficiently, the treatment time is preferably 10 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more. On the other hand, from the viewpoint of suppressing erosion of the refractory and suppressing energy consumption, the treatment time is preferably 48 hours or less, more preferably 24 hours or less, and even more preferably 12 hours or less.

[0051] In the reduction treatment, it is preferable to selectively generate impurity elements in the first molten material as a metal phase. This reduces the change between the main components of the glass in the glass-containing raw material and the main components of the resulting glass, which is advantageous because it allows recycling while leaving useful components intact. In order to selectively generate impurity elements as a metal phase, it is preferable to appropriately adjust conditions such as the type of reducing agent and the treatment temperature in the reduction treatment. For example, by setting these to the above-mentioned preferred conditions, it tends to be easier to selectively generate impurity elements in the first molten material as a metal phase.

[0052] (Metal Phase) The metal elements contained in the first melt are generated as a metal phase in the first melt by reduction treatment. The metal phase contains at least the elements contained in the glass-containing raw material or the first melt before reduction treatment, and preferably contains the above-mentioned impurity elements. The larger the proportion of the impurity elements in the metal phase, the more selectively the impurity elements are generated as a metal phase, which is preferable.

[0053] [Step (iii)] In step (iii), at least a portion of the metal phase is separated from the reduced first melt to obtain a second melt. Here, "separating at least a portion of the metal phase from the first melt" means physically removing at least a portion of the metal phase from the first melt, and the second melt means the first melt from which at least a portion of the metal phase has been removed.

[0054] The method for separating the metal phase is not particularly limited, but examples thereof include a method of coarsening the metal phase generated in the first melt by bubbling until it is large enough to precipitate metal fine particles, and then separating the precipitate; a method of intentionally adding a metal component such as silicon to combine with the generated metal fine particles, coarsening them until it is large enough to precipitate, and then separating the precipitate; a method of generating a metal phase on the surface of a reducing agent, capturing the metal phase on the surface of the reducing agent, and then separating the metal phase; a method of converting the metal phase into a highly volatile substance by halogenation or the like, and separating it as a gas, etc. These methods are preferred because they make it easy to obtain a metal fine particle-containing glass in which the number density of the metal fine particles per particle size is within the range described below. From the viewpoint of ease of handling and high separation efficiency, the following methods are preferred: by bubbling, the metal particles are coarsened to a size sufficient for precipitation, and then separated; by intentionally adding a metal component such as silicon, the metal particles are bonded to the metal particles generated, and then coarsened to a size sufficient for precipitation, and then separated; by generating a metal phase on the surface of the reducing agent, the metal phase is captured on the surface of the reducing agent, and then separated; and more preferably, by generating a metal phase on the surface of the reducing agent, the metal phase is captured on the surface of the reducing agent, and then separated. Note that, as a specific method for generating a metal phase on the surface of the reducing agent, the metal phase can be captured on the surface of the reducing agent, for example, by filling a container with the reducing agent in advance, and melting the glass-containing raw material in the container, and then passing the first melt through the reducing agent. Step (ii) and step (iii) may be performed in parallel.

[0055] After steps (i) to (iii), a metal fine particle-containing glass is obtained from the second molten material obtained. The production method may include a step of cooling the second molten material by a known method and a step of shaping the second molten material.

[0056] (Metal Microparticle-Containing Glass) The metal microparticle-containing glass obtained by the present production method is glass containing metal microparticles, and it is preferable that the number density of the metal microparticles for each particle size in an arbitrary cross section is in the following range, and the area ratio of the metal microparticles in the arbitrary cross section to the total area is 0 to 0.10%: Particle size greater than 1 μm and equal to or less than 5 μm: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２ Particle size over 500 μm: substantially not contained

[0057] According to the studies of the present inventors, when the generated metal phase is separated from the melt, although some impurity elements are removed, the metal phase in the form of fine particles remains in the melt. Here, it has been found that if the particle size distribution of the metal phase in the form of fine particles is within the above-mentioned specific range, the metal phase in the form of fine particles can be oxidized and contained in the glass in the form of oxide by further performing an oxidation treatment on the melt containing the metal phase in the form of fine particles (i.e., the fine particles can be eliminated). In other words, by setting the particle size distribution of the metal phase in the form of fine particles within the specific range, it is possible to suppress the remaining of fine particles after the oxidation treatment and the decrease in the transparency of the glass obtained after the oxidation treatment, and it is easy to obtain high-quality glass.

[0058] The present invention also relates to the above-mentioned metal-particle-containing glass. The metal-particle-containing glass according to this embodiment may be obtained by melting a glass-containing raw material and reducing the resulting molten material with a reducing agent for glass containing SiC.

[0059] In this specification, metal microparticles in glass are observed using an optical microscope (digital microscope) under epi-illumination. Using epi-illumination, observations can be easily focused on the surface, and high-contrast observations are possible because the metal microparticles reflect light. Specifically, after polishing an arbitrary cross section of the metal microparticle-containing glass, images are taken at 16 locations at 200x and 1000x magnifications. Image analysis is performed using image analysis software to calculate the area of ​​each particle contained in a total of 32 captured images, and the diameter obtained when the area of ​​the resulting particle is assumed to be a sphere is defined as the particle size. It has been confirmed that the metal microparticles are approximately spherical, as observed using scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), as described below, and that the shape is consistent with the image observed using an optical microscope. From the perspective of measurement accuracy, only particles with a particle size greater than 5 μm are counted at 200x magnification, and only particles greater than 1 μm and up to 5 μm are counted at 1000x magnification. Furthermore, the particle size distribution of each image is determined by image analysis, and the number density of metal microparticles for each particle size is determined by dividing the total area of ​​the field of view of the observed image by the number of particles of a specific particle size observed. Furthermore, the area ratio of metal microparticles is determined by dividing the total area of ​​the field of view of the observed image by the total area of ​​the metal microparticles observed. Note that "substantially free of metal microparticles of a specific particle size" means that no metal microparticles of that particle size are observed by the above-mentioned method.

[0060] Fig. 1A is a diagram showing an example of an image of the metal-microparticle-containing glass according to this embodiment photographed at 200x magnification by the above-mentioned method, Fig. 1B is a diagram showing an image after image processing of Fig. 1A. Fig. 2A is a diagram showing an example of an image of the metal-microparticle-containing glass according to this embodiment photographed at 1000x magnification by the above-mentioned method, and Fig. 2B is a diagram showing an image after image processing of Fig. 2A.

[0061] In this specification, unless otherwise specified, the element concentration (composition) in metal fine particle-containing glass refers to the average concentration (average composition) including the elements contained in the metal fine particles. This can be measured by X-ray fluorescence analysis. Furthermore, the main components of the metal fine particles can be measured by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX).

[0062] The metal microparticle-containing glass obtained by this production method is glass containing metal microparticles, and it is preferable that the number density of the metal microparticles per particle size in any cross section is within the above-mentioned range, thereby obtaining high-quality glass in which manufacturing defects and unwanted coloring are suppressed when the glass is subjected to oxidation treatment.

[0063] In the glass containing metal particles, the number density of particles with a particle size of more than 1 μm and not more than 5 μm is 0 to 500 particles / mm ２ That is, the number density of particles having a particle size of more than 1 μm and not more than 5 μm is preferably 500 particles / mm ２ It is preferable that the number of particles is 400 or less per mm. ２ More preferably, 300 or less per mm ２ More preferably, 200 pieces / mm ２ The following is particularly preferred. This allows the visible light transmittance of the glass after oxidation treatment to be increased, and high-quality glass to be obtained in a short oxidation treatment time. The number density of particles having a particle size of more than 1 μm and not more than 5 μm is 0 particles / mm ２ or more, and ２ More than 5 pieces / mm ２ More preferably, 10 pieces / mm ２ The above is more preferable. This allows radiant heat to be efficiently absorbed when melting the metal fine particle-containing glass, thereby reducing energy consumption.

[0064] In the glass containing metal particles, the number density of particles with a particle size of more than 5 μm and not more than 10 μm is 0 to 30 particles / mm ２ That is, the number density of particles having a particle diameter of more than 5 μm and not more than 10 μm is preferably 30 particles / mm ２ It is preferable that the number of particles is 20 or less per mm. ２ More preferably, 10 or less per mm ２ More preferably, 6 or less pieces / mm２ The following is particularly preferred. This allows the visible light transmittance of the glass after oxidation treatment to be increased, and high-quality glass to be obtained in a short oxidation treatment time. The number density of particles having a particle size of more than 5 μm and not more than 10 μm is 0 particles / mm ２ or more, and 0.05 pieces / mm ２ More than 0.1 pieces / mm ２ This is more preferable. This allows radiant heat to be efficiently absorbed when melting the metal fine particle-containing glass, thereby reducing energy consumption.

[0065] In the glass containing metal particles, the number density of particles with a particle size of more than 10 μm and not more than 100 μm is 0 to 5 particles / mm ２ That is, the number density of particles having a particle diameter of more than 10 μm and not more than 100 μm is preferably 5 particles / mm ２ It is preferable that the number of particles is 3 or less per mm. ２ More preferably, 2 or less pieces / mm ２ More preferably, 1 piece / mm ２ Particularly preferred is 0.5 pieces / mm ２ This makes it possible to increase the visible light transmittance of the glass after oxidation treatment, and to obtain high-quality glass in a short oxidation treatment time. It is not necessary to contain particles with a particle size of more than 10 μm and not more than 100 μm, but from the viewpoint of efficiently absorbing radiant heat and suppressing energy consumption when melting the metal microparticle-containing glass, it is preferable to have a particle size of 0.1 particles / mm ２ It may be more than that.

[0066] In the glass containing metal particles, the number density of particles with a particle size of more than 100 μm and not more than 500 μm is 0 to 0.5 particles / mm ２ That is, the number density of particles having a particle diameter of more than 100 μm and not more than 500 μm is preferably 0.5 particles / mm ２ It is preferable that the number of particles is 0.3 or less per mm. ２ More preferably, 0.2 pieces / mm or less ２ More preferably, 0.1 pieces / mm or less ２The following is particularly preferred. This allows the visible light transmittance of the glass after oxidation treatment to be increased, and high-quality glass to be obtained in a short oxidation treatment time. Particles with a particle size of more than 10 μm and not more than 100 μm may not be included, but from the viewpoint of efficiently absorbing radiant heat and suppressing energy consumption when melting the metal fine particle-containing glass, it is preferable that the particle size be 0.01 particles / mm ２ It may be more than that.

[0067] Particles with a particle size of more than 500 μm are not substantially contained, but if they are contained, they can be removed in a subsequent process using a metal detector or optical sorter.

[0068] In the metal microparticle-containing glass, the area ratio of the metal microparticles in the arbitrary cross section is preferably 0 to 0.10% of the total area. The area ratio is more preferably 0.08% or less, and even more preferably 0.06% or less. This makes it possible to suppress unnecessary coloration during oxidation treatment. The area ratio is 0% or more, preferably 0.001% or more, more preferably 0.002% or more, and even more preferably 0.003% or more. This makes it possible to efficiently absorb radiant heat when melting the metal microparticle-containing glass, thereby suppressing energy consumption. The area ratio can be determined by observing an arbitrary cross section of the metal microparticle-containing glass using an optical microscope and analyzing the image using the above-mentioned method, and dividing the total area of ​​the observed metal microparticles by the total area of ​​the observed field of view of the image.

[0069] The shape of the metal fine particles may be, for example, approximately spherical or approximately perfect spherical.

[0070] In the glass containing metal particles, the visible light transmittance Tv at a thickness of 2 mm and the transmittance T at a wavelength of 1100 nm １１００ The absolute value of the difference ABS (Tv-T １１００ ) is preferably 2.0% or less. In glass containing metal fine particles, impurity elements are generated as a metal phase, so the content of impurity elements remaining in the glass phase is relatively small. In this case, absorption due to impurity elements such as coloring elements is reduced. Transmittance T at a wavelength of 1100 nm １１００ is Fe ２＋ That is, it is affected by the magnitude of light absorption due to ABS (Tv-T１１００ A relatively small ABS (Tv-T) is preferable because it means that when the glass-containing raw material contains Fe as an impurity element, Fe is sufficiently generated as a metal phase in the metal fine particle-containing glass. １１００ ) is more preferably 1.5% or less, and even more preferably 1.0% or less. １１００ ) is preferably as small as possible, and therefore, the lower limit is not particularly limited.

[0071] In this specification, the visible light transmittance Tv refers to the value of the visible light transmittance Tv at a thickness of 2 mm measured according to JIS R3106:2019. For glass thicker than 2 mm, measurement can be performed by polishing to 2 mm using a general method. For glass thinner than 2 mm, measurement can be performed by remelting in an inert gas in a general electric furnace so as not to oxidize the metal particles, obtaining glass with a thickness of 2 mm or more, and then polishing to 2 mm. T １１００ means the transmittance at a wavelength of 1100 nm at a thickness of 2 mm.

[0072] In the metal microparticle-containing glass, the metal microparticles preferably contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb. When the metal microparticle-containing glass is obtained by the above-mentioned method, the metal microparticles contain at least some of the elements contained in the glass-containing raw material or the first molten material before the reduction treatment. It can be said that the above elements are elements that are easily contained in the metal microparticles, originating from the elements contained in the glass-containing raw material or the first molten material before the reduction treatment.

[0073] The total content of network-forming oxides contained in the glass-containing raw material, calculated as a mass% on an oxide basis (NWF) ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total NWM of the contents of network modifier oxides contained in the glass-containing raw material ｂｅｆｏｒｅ and the total NWM of the contents of network modifying oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅis preferably 0.60 to 2.00. ａｆｔｅｒ／ｂｅｆｏｒｅ is preferably 0.40 or more, more preferably 0.50 or more, and even more preferably 0.60 or more. ａｆｔｅｒ／ｂｅｆｏｒｅ is preferably 1.50 or less, more preferably 1.30 or less, and even more preferably 1.20 or less. ａｆｔｅｒ／ｂｅｆｏｒｅ is preferably 0.60 or more, more preferably 0.70 or more, and even more preferably 0.80 or more. ａｆｔｅｒ／ｂｅｆｏｒｅ is preferably 2.00 or less, more preferably 1.60 or less, and even more preferably 1.40 or less.

[0074] Both the network-forming oxides and the network-modifying oxides constitute the main components of the glass. ａｆｔｅｒ／ｂｅｆｏｒｅ and N.W.M. ａｆｔｅｒ／ｂｅｆｏｒｅ The fact that each of these is in the above range means that there is little change between the main components of the glass in the glass-containing raw material and the main components of the metal fine particle-containing glass, which is preferable from the viewpoint of being able to recycle the glass as a raw material while leaving useful components.

[0075] In this specification, the total content of network-forming oxides means SiO ２ , Al ２ O ３ , B ２ O ３ and P ２ O ５ The total content of the network modifying oxides means the total content of MgO, CaO, SrO, BaO, Li ２ O, Na ２ O and K ２ It means the total content of O.

[0076] Average Fe in metal particle-containing glass ２ O ３ The concentration is preferably 0.001% to 0.5% by mass on an oxide basis. This means that the content of impurity elements, especially Fe element, in the metal fine particle-containing glass is relatively low. ２ O ３ The concentration is preferably 0.5% or less, more preferably 0.4% or less, and even more preferably 0.3% or less.２ O ３ The lower the concentration, the better, and the lower limit is not particularly limited, but may be, for example, 0.001% or more. ２ O ３ The concentration is not only trivalent iron ions, but also divalent iron ions and metallic iron. ２ O ３ This is the total value converted into concentration.

[0077] The composition (average composition) of the metal-particle-containing glass is not particularly limited, and may be, for example, a glass selected from the group consisting of soda-lime glass, aluminosilicate glass, alkali-free glass, and alkali borosilicate glass. Soda-lime glass is preferred from the viewpoints of the world's largest production volume and its significant contribution to resource recycling and greenhouse gas reduction. The glass composition of the glass-containing raw material used to produce the metal-particle-containing glass is also not particularly limited, and may be the same as the composition of the metal-particle-containing glass, except for the content of impurity elements.

[0078] When the metal fine particle-containing glass is soda lime glass, its composition is expressed as mass % based on oxides, and is SiO ２ and Al ２ O ３ 50 to 85% in total, alkaline earth metal oxides (RO) 5 to 30% in total, alkali metal oxides (R ２ O) in a total amount of 0.1 to 25%. More preferably, SiO ２ 60-80%, Na ２ O 0.1 to 25%, MgO 0 to 15%, CaO 5 to 20%, Al ２ O ３ Contains 0 to 10% of K. ２ It may contain less than 5% of O. An example of a preferred composition when the metal fine particle-containing glass is soda-lime glass will be described in more detail below. Note that when the glass composition is expressed as % or ppm, it means mass % based on oxide or mass ppm based on oxide unless otherwise specified.

[0079] SiO ２ and Al ２ O ３The total content of SiO is preferably 50 to 85%. ２ and Al ２ O ３ If the total content of SiO is 50% or more, the glass can exist stably and the weather resistance is high, which is preferable. ２ and Al ２ O ３ The total content of SiO is more preferably 55% or more, and further preferably 60% or more. ２ and Al ２ O ３ If the total content of SiO is 85% or less, the reduction reaction rate and the oxidation reaction rate become high, which is preferable. ２ and Al ２ O ３ The total content is more preferably 80% or less, and further preferably 78% or less.

[0080] SiO ２ is the main component of soda-lime glass. ２ The content of SiO is preferably 50 to 80%. ２ If the content is 50% or more, the weather resistance becomes good, which is preferable. ２ The content of SiO is more preferably 60% or more, and even more preferably 65% ​​or more. ２ If the content is 80% or less, devitrification is unlikely to occur, which is preferable. ２ The content is more preferably 75% or less, and even more preferably 73% or less.

[0081] Al ２ O ３ is a component that improves weather resistance. ２ O ３ The content of Al is preferably 0 to 20%. ２ O ３ When the aluminum alloy contains Al, the weather resistance is improved. ２ O ３ The content of Al is preferably 0% or more, more preferably 0.1% or more, even more preferably 0.5% or more, and particularly preferably 1% or more. ２ O ３ The content of is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less, from the viewpoint of lowering the viscosity during melting and making it difficult for devitrification to occur.

[0082] The total content of alkaline earth metal oxides (RO) is preferably 5 to 30%. If the total content of alkaline earth metal oxides (RO) is 5% or more, the solubility becomes good, which is preferable. The total content of alkaline earth metal oxides (RO) is more preferably 7% or more, and even more preferably 10% or more. If the total content of alkaline earth metal oxides (RO) is 30% or less, the devitrification becomes less likely, which is preferable. The total content of alkaline earth metal oxides (RO) is more preferably 25% or less, and even more preferably 20% or less. Here, the total content of alkaline earth metal oxides (RO) means the total content of MgO, CaO, SrO, and BaO.

[0083] MgO is a component that promotes the melting of glass raw materials and improves weather resistance. The MgO content is preferably 0 to 15%. The inclusion of MgO improves melting property and weather resistance. The MgO content is preferably 0% or more, more preferably 1% or more, even more preferably 2% or more, and particularly preferably 4% or more. If the MgO content is 15% or less, it is preferable because devitrification is less likely to occur. The MgO content is more preferably 10% or less, and even more preferably 5% or less.

[0084] CaO is a component that promotes the melting of glass raw materials and improves weather resistance. The CaO content is preferably 5 to 20%. If the CaO content is 5% or more, the melting property and weather resistance become good, which is preferable. The CaO content is more preferably 6% or more, and even more preferably 7% or more. If the CaO content is 20% or less, the glass becomes less susceptible to devitrification, which is preferable. The CaO content is more preferably 15% or less, and even more preferably 12% or less.

[0085] Alkali metal oxide (R ２ The total content of alkali metal oxides (R O) is preferably 0.1 to 25%. ２ If the total content of alkali metal oxides (R O) is 0.1% or more, the solubility becomes good, which is preferable. ２ The total content of alkali metal oxides (R O) is more preferably 1% or more, further preferably 3% or more, and particularly preferably 5% or more. ２If the total content of alkali metal oxides (R O) is 25% or less, the weather resistance becomes good, which is preferable. ２ The total content of alkali metal oxides (R O) is more preferably 20% or less, and further preferably 15% or less. ２ The total content of Li ２ O, Na ２ O and K ２ The total content of O is

[0086] Na ２ O is a component that promotes the melting of glass raw materials. ２ The content of O is preferably 0.1 to 25%. ２ If the O content is 0.1% or more, the solubility becomes good, which is preferable. ２ The O content is more preferably 1% or more, further preferably 3% or more, and particularly preferably 5% or more. ２ If the O content is 25% or less, the weather resistance becomes good, which is preferable. ２ The O content is more preferably 20% or less, and further preferably 15% or less.

[0087] K ２ O is a component that promotes the melting of glass raw materials. ２ O is not essential, but may be contained in an amount of less than 5%. ２ The content of O may be 0% or more and less than 5%. ２ The inclusion of O improves the solubility. ２ When O is contained, the content thereof is preferably 0.01% or more, and more preferably 0.5% or more. ２ If the O content is less than 5%, the weather resistance becomes good, which is preferable. ２ The O content is more preferably 3% or less, and further preferably 2% or less.

[0088] The composition (average composition) of the glass obtained by this manufacturing method can be measured by composition analysis using fluorescent X-ray analysis. ２ O, B ２ O ３It may be difficult to quantify the light element components such as those mentioned above by fluorescent X-ray analysis, and the composition may be analyzed by analysis using an electron probe microanalyzer (EPMA), ICP emission spectrometry, or ICP mass spectrometry.

[0089] The shape of the metal microparticle-containing glass is not particularly limited and may be various shapes such as block, broken pieces, container, fiber, bead, or plate. When the glass is plate-shaped, it may be flat or may be formed or bent to include a curved surface. When the glass is plate-shaped, the thickness is not particularly limited, but is preferably 0.1 to 20 mm, for example. When the metal microparticle-containing glass is used as a glass raw material, from the viewpoint of ease of handling, the shape that accounts for 80% or more of the total metal microparticle-containing glass by mass is preferably broken pieces or spheres having a size of 1 to 100 mm, more preferably broken pieces or spheres having a size of 3 to 50 mm. Broken pieces of glass are, for example, glass crushed by a common mechanical crushing method such as water granulation or a roll crusher, and are generally called cullets. Spherical glass can also be produced using wind force, such as by gas atomization. The size and proportion of glass can be evaluated by passing it through a sieve with a specified mesh size and measuring the mass on a balance. Note that this does not include tiny pieces of glass that are generated by collisions between pieces of glass during transportation.

[0090] (Oxidation Treatment) By subjecting the above-mentioned metal microparticle-containing glass to an oxidation treatment, high-quality glass can be obtained in which manufacturing defects and unnecessary coloring are suppressed. That is, it is preferable to obtain glass by subjecting a melt (hereinafter also referred to as a third melt) obtained by melting the metal microparticle-containing glass to an oxidation treatment. The oxidation treatment method is not particularly limited, and examples thereof include a method using an oxidizing gas and a method adding an oxidizing agent. The method using an oxidizing gas is preferred because it is less likely to cause changes in the composition of the melt.

[0091] Specific examples of the oxidizing gas include O ２ Gas containing H ２ O-containing gas, CO ２From the viewpoint of oxidation efficiency and availability, the oxidizing gas is preferably O ２ A gas containing O is preferred. ２ Examples of gases containing O include air (atmosphere), O ２ Gas, O ２ Examples of suitable gases include a mixture of an oxygen gas and an inert gas, and from the viewpoint of availability, air (atmosphere), O ２ Gas is preferred.

[0092] A specific example of a method for performing the oxidation treatment using an oxidizing gas is bubbling the third molten material with the oxidizing gas. If necessary, the oxidizing gas may be mixed with an inert gas. Examples of the inert gas include nitrogen gas, argon gas, and helium gas.

[0093] Specific examples of the oxidizing agent include nitrates such as sodium nitrate, sulfates such as sodium sulfate, cerium oxide, antimony(V) oxide, tin(IV) oxide, etc. From the viewpoints of oxidation efficiency, ease of availability, and environmental impact, nitrates, cerium oxide, and tin(IV) oxide are preferred.

[0094] A specific example of a method for carrying out the oxidation treatment using an oxidizing agent is a method of adding the oxidizing agent to the third melt. The oxidizing agent is preferably in powder form to ensure efficient reaction. The addition method is preferably a powder injection method to ensure efficient reaction.

[0095] The treatment temperature in the oxidation treatment is preferably 1300° C. to 1800° C. That is, from the viewpoint of ensuring a sufficient oxidation reaction rate, the treatment temperature is preferably 1300° C. or higher, more preferably 1400° C. or higher, and even more preferably 1450° C. or higher. On the other hand, from the viewpoint of suppressing erosion of the refractory and suppressing energy consumption, the treatment temperature is preferably 1800° C. or lower, more preferably 1700° C. or lower, and even more preferably 1650° C. or lower.

[0096] The oxidation treatment time is not particularly limited, but when bubbling with an oxidizing gas, for example, 1 minute to 24 hours is preferable. That is, from the viewpoint of sufficiently eliminating the metal fine particles, the treatment time is preferably 1 minute or more, more preferably 5 minutes or more, and even more preferably 15 minutes or more. On the other hand, from the viewpoint of suppressing erosion of the refractory and suppressing energy consumption, the treatment time is preferably 24 hours or less, more preferably 12 hours or less, and even more preferably 8 hours or less.

[0097] The oxidation treatment described above allows high-quality glass to be produced from glass containing metal fine particles. After the oxidation treatment, known steps such as a glass composition adjustment step, a forming step, and a slow cooling step may be carried out.

[0098] (Uses) The reducing agent for glass of the present invention can be used to properly and quickly remove unnecessary substances and components from glass containing foreign matter, etc., or glass containing colored components or unnecessary components. In other words, the reducing agent for glass of the present invention can be used to suitably recycle various waste glass products, defective glass, etc. containing unnecessary substances and unnecessary components.

[0099] [Glass Recycling Method] The present invention also relates to a glass recycling method. The glass recycling method according to an embodiment of the present invention includes melting a glass-containing raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components to obtain a molten material, and subjecting the molten material to a reduction treatment using the above-mentioned reducing agent for glass. The glass recycling method according to an embodiment of the present invention may further include subjecting the molten material to an oxidation treatment.

[0100] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these. Examples 1 to 3 are working examples, and Examples 4 and 5 are comparative examples.

[0101] (Reducing Agent) Reducing agents I to III listed in Table 1 were prepared. Reducing agents I to III were prepared by pulverizing the following commercially available products in a mortar and classifying them using sieves with openings of 2.36 mm and 5.6 mm. Commercial product I: F coke (low ASH) (manufactured by Nippon Steel Corporation) Commercial product II: activated carbon (granular) (manufactured by Kanto Chemical Co., Inc.) Commercial product III: recrystallized SiC (manufactured by Taiko Ceramic Co., Ltd.)

[0102] The bulk density, apparent density, true density, porosity, and packing ratio of reducing agents I to III, and the mixture of reducing agents I and III used in Example 2 and Example 3 described below, were measured or calculated using the methods described in the specification. The median pore diameters of reducing agents I and III were measured by mercury porosimetry, and the median pore diameter of reducing agent II was measured using the BET method. The presence or absence of interconnected pores was confirmed by embedding the reducing agent in a two-component curing epoxy resin, reducing the pressure to 0.1 atmospheres or less using a vacuum pump, removing internal air bubbles, and then curing the resin, exposing the cross section, and observing whether the resin had impregnated the interior.

[0103]

[0104] (Glass-containing raw materials) Glass A having the composition shown in Table 2, expressed in mass % based on oxides, was prepared. The total value of RO was broken down as follows: MgO 4%, CaO 8%, SrO and BaO each less than 0.1%, and R ２ The breakdown of the total value of O is Na ２ O is 12.5%, K ２ O is 0.5%.

[0105]

[0106] (Example 1) Glass A was used as the glass-containing raw material, placed in an alumina crucible, and melted in an electric furnace under a nitrogen atmosphere by heating to 1500°C to obtain a first melt. Using reducing agent III as the reducing agent, the first melt was passed through a reducing agent previously placed in an alumina crucible at a mass ratio of 0.4 to the first melt and a filling rate of approximately 60% by volume, thereby generating a metal phase. The reduction treatment was performed at 1500°C and for 120 minutes. This treatment generated a metal phase on the surface of the reducing agent, which was then captured on the surface of the reducing agent. The mixture was then allowed to stand, allowing relatively large metal particles to settle. The crucible was then slowly cooled, and the bottom was physically cut by 3 to 5 mm to separate the settled metal particles, thereby separating at least a portion of the metal phase. The metal-particle-containing glass of Example 1 was obtained as the cooled second melt.

[0107] Examples 2 to 5 As shown in Table 3, metal fine particle-containing glass of each example was obtained in the same manner as in Example 1, except that the type of reducing agent used and, when multiple reducing agents were used, the compounding ratio thereof were changed.

[0108] <Evaluation> The metal fine particle-containing glasses of Examples 1 to 5 were evaluated by the following methods. The results are shown in Table 3.

[0109] (Number Density and Area Ratio of Metallic Microparticles) Observation was performed using a digital microscope (Keyence Corporation, Model No. VHX-8000) under epi-illumination. After polishing at an arbitrary cross section, images were taken at 16 locations at 200x and 1000x magnifications, and image analysis was performed using the image analysis software ImageJ. First, the image was converted to 8-bit, and then, while checking the image, a threshold value representing the boundary between particles and glass was set using the Threshold function. Then, the Analyze Particle function was used to calculate the area of ​​each particle contained in the image, and the particle size distribution of each image was determined. The number density of metal microparticles for each particle size was determined by dividing the total area of ​​the field of view of the observed image by the number of particles of a specific diameter observed. Furthermore, the area ratio of metal microparticles was determined by dividing the total area of ​​the field of view of the observed image by the total area of ​​the metal microparticles observed. From the viewpoint of measurement accuracy, only particles with a particle size of more than 5 μm were counted at a magnification of 200x, and only particles with a particle size of more than 1 μm and up to 5 μm were counted at a magnification of 1000x. Observation and analysis were performed on the metal microparticle-containing glass of each example. As examples of photographed images and images after image processing, FIG. 1A shows an image of an arbitrary cross section of the metal microparticle-containing glass of Example 1 photographed at 200x. FIG. 1B shows the image of FIG. 1A after image processing. FIG. 2A shows an image of an arbitrary cross section of the metal microparticle-containing glass of Example 1 photographed at 1000x. FIG. 2B shows the image of FIG. 2A after image processing.

[0110] (Main Components of Metallic Fine Particles) The main components of the metallic fine particles were measured by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX).

[0111] (ABS (Tv-T １１００ The visible light transmittance Tv was measured using a spectrophotometer (Hitachi High-Tech Science Corporation, model number UH4100) in accordance with JIS R3106:2019. １１００ The measurement was carried out on the metal fine particle-containing glass of each example, and a sample having a thickness of 2 mm was used for the measurement.

[0112] (Composition, Fe ２ O ３Concentration) The composition and impurity element concentration in terms of mass % of the metal fine particle-containing glass of each example and glass A were measured as follows: ２ , Al ２ O ３ , RO and R ２ O) and Fe ２ O ３ The concentration was measured by fluorescent X-ray analysis. However, when an alumina crucible or alumina pipe is used in the reduction treatment, Al may be unintentionally introduced into the glass. ２ O ３ is dissolved, and Al ２ O ３ The Al concentration in the glass after treatment may be high. ２ O ３ The concentration is the Al content of the glass-containing raw material. ２ O ３ In the scope of the present invention, the alumina crucible and the alumina pipe are dissolved in the glass, and the Al concentration in the glass is also calculated. ２ O ３ It has been confirmed that there is no change in the concentration.

[0113]

[0114] As shown in Table 3, the metal microparticle-containing glasses of Examples 1 to 3, which are working examples, have a lower area ratio of metal microparticles and a lower number density of metal microparticles, particularly a lower number density of metal microparticles with a size of more than 1 μm and 5 μm or less, compared to the metal microparticle-containing glasses of Comparative Examples 4 and 5, demonstrating that unnecessary components can be removed quickly. Furthermore, it was found that there was little change in the main components of the glass in the glass-containing raw material and the main components of the glass in the metal microparticle-containing glass, enabling the unnecessary components to be appropriately removed.

[0115] <Experiment to confirm the effect of interconnected pores> In an experiment to confirm the effect of interconnected pores in a reducing agent for glass, a comparative experiment was conducted between graphite (without interconnected pores) and binchotan charcoal (with interconnected pores), both of which contain carbon as their main component.

[0116] In an alumina crucible (Φ21.5 mm x height 43 mm), Fe ２ O ３Eight grams of soda-lime glass with a concentration of 1.5% by mass and a plate-shaped reducing agent for glass (graphite or binchotan charcoal, 3 mm x 5 mm x 50 mm) were added, and while Ar gas was blown in at a flow rate of 20 mL / min, the temperature was raised to 1500°C in an electric furnace to melt the glass. The glass was then maintained at that temperature for 30 minutes to carry out a reduction treatment. The reducing agent was then removed from the molten glass, and the temperature was then quickly lowered.

[0117] The efficiency of the reduction treatment of the glass was evaluated using this treatment. When the appearance of the glass after cooling was observed, the sample using graphite as the reducing agent was blue, but the sample using binchotan charcoal was black. The blue coloration is due to the divalent Fe ions contained in the glass, and indicates that the reduction had not progressed sufficiently compared to the sample using binchotan charcoal. The glass was then embedded in resin together with the alumina crucible, cut in the height direction, and mirror-polished to a thickness of approximately 2 mm, and the microstructure was observed using SEM-EDX, and the metal particles and glass composition were analyzed. In all samples, metal particles were dispersed in the glass, and the metal particles were mainly composed of Fe and Si. Regarding the glass composition, when graphite was used as the reducing agent, Fe ２ O ３ The concentration was 1.0 mass % when binchotan charcoal was used, and 0.3 mass % when binchotan charcoal was used. It was found that the reduction treatment efficiency was higher when binchotan charcoal, which has interconnected pores, was used than when graphite, which does not have interconnected pores, and that more unnecessary components were removed.

[0118] As explained above, the present specification discloses the following: 1. A reducing agent for glass containing SiC. 2. The reducing agent for glass according to 1, which has interconnected pores. 3. The reducing agent for glass according to 1 or 2, which contains a mixture or composite of SiC and C. 4. The reducing agent for glass according to any one of 1 to 3, in which the volume ratio of SiC to the entire reducing agent is 0.01 to 1. 5. A reducing agent for glass having a bulk density of 0.55 to 1.50 g / cm ３ , apparent density is 1.60 to 3.00 g / cm ３ , true density is 2.15 to 3.50 g / cm ３5. The reducing agent for glass according to any one of 1 to 4, having a porosity of 5 to 50% and a filling rate of 40 to 80%. 6. The reducing agent for glass according to any one of 1 to 5, in the form of chunks or broken pieces, with a size of 1 to 100 mm. 7. The reducing agent for glass according to any one of 1 to 6, which acts by contacting with a molten material obtained by melting a glass-containing raw material. 8. The reducing agent for glass according to 7, wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components. 9. A method for producing metal fine particle-containing glass containing metal fine particles, comprising: melting a glass-containing raw material containing glass to obtain a molten material; and reducing the molten material using the reducing agent for glass according to any one of 1 to 8. 10. The method for producing metal fine particle-containing glass according to 9, wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components. 11. 12. The method for producing metal fine particle-containing glass according to 9 or 10, wherein the treatment temperature in the reduction treatment is 1300° C. to 1800° C. 12. The method for producing metal fine particle-containing glass according to any one of 9 to 11, wherein the number density of the metal fine particles per particle size in an arbitrary cross section of the metal fine particle-containing glass is in the following range, and the area ratio of the metal fine particles in the arbitrary cross section to the total area is 0 to 0.10%: Particle size greater than 1 μm and 5 μm or less: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２ Particle size greater than 500 μm: substantially not contained 13. The metal fine particle-containing glass has a visible light transmittance Tv at a thickness of 2 mm and a transmittance T at a wavelength of 1100 nm １１００ The absolute value of the difference ABS (Tv-T １１００14. The method for producing metal fine particle-containing glass according to any one of items 9 to 13, wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb. 15. The total content NWF of network forming oxides contained in the glass-containing raw material, calculated as mass % on an oxide basis, is ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total NWM of the contents of network modifier oxides contained in the glass-containing raw material is ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ 16. The method for producing metal fine particle-containing glass according to any one of 9 to 14, wherein the average Fe in the metal fine particle-containing glass is 0.60 to 2.00. ２ O ３ The method for producing metal fine particle-containing glass according to any one of items 9 to 15, wherein the concentration is 0.001% to 0.5% expressed as mass % on an oxide basis. 17. Glass containing metal fine particles, wherein the number density of the metal fine particles for each particle size in an arbitrary cross section is within the following range, and the area ratio of the metal fine particles in the arbitrary cross section to the total area is 0 to 0.10%: Particle size greater than 1 μm and 5 μm or less: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２Particle size greater than 500 μm: substantially not contained 18. Metal fine particle-containing glass according to 17, obtained by melting a glass-containing raw material and reducing the resulting molten material with a reducing agent for glass containing SiC. 19. Metal fine particle-containing glass according to 17 or 18, wherein the glass-containing raw material is a raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components. 20. Visible light transmittance Tv at a thickness of 2 mm and transmittance T at a wavelength of 1100 nm １１００ The absolute value of the difference ABS (Tv-T １１００ 21. The metal fine particle-containing glass according to any one of 17 to 19, wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb. 22. The total content NWF of network-forming oxides contained in the glass-containing raw materials, calculated as mass % on an oxide basis, is ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total content NWM of network modifier oxides contained in the glass-containing raw material ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ 22. The metal-particle-containing glass according to any one of 17 to 21, wherein the average Fe in the metal-particle-containing glass is 0.60 to 2.00. ２ O ３23. The metal fine particle-containing glass according to any one of 17 to 22, having a concentration of 0.001% to 0.5% expressed in mass % on an oxide basis. 24. A method for recycling glass, comprising: melting a glass-containing raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components to obtain a molten material; and subjecting the molten material to a reduction treatment using the reducing agent for glass according to any one of 1 to 8. 25. The method for recycling glass according to 24, further comprising subjecting the molten material to an oxidation treatment.

[0119] According to the present invention, a reducing agent for glass can be provided that can appropriately and quickly remove unnecessary substances and components from glass containing foreign matter or glass containing colored components or unnecessary components.

[0120] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-150748) filed on September 2, 2024, the contents of which are incorporated herein by reference.

Claims

1. A reducing agent for glass containing SiC.

2. The reducing agent for glass according to claim 1, which has interconnected pores.

3. The reducing agent for glass according to claim 1 or 2, which contains a mixture or composite of SiC and C.

4. The reducing agent for glass according to claim 1 or 2, wherein the volume ratio of SiC to the entire reducing agent is 0.01 to 1.

5. Bulk density of 0.55 to 1.50 g / cm ３ , apparent density is 1.60 to 3.00 g / cm ３ , true density is 2.15 to 3.50 g / cm ３ 3. The reducing agent for glass according to claim 1, wherein the reducing agent has a porosity of 5 to 50% and a filling rate of 40 to 80%.

6. The reducing agent for glass according to claim 1 or 2, which is in the form of lumps or crushed pieces, the size of which is 1 to 100 mm.

7. The reducing agent for glass according to claim 1, which acts by contacting with a melt obtained by melting glass-containing raw materials.

8. The reducing agent for glass according to claim 7, wherein the glass-containing raw material is a raw material containing at least one selected from the group consisting of glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components.

9. A method for producing metal particle-containing glass containing metal particles, comprising: melting a glass-containing raw material containing glass to obtain a molten material; and reducing the molten material using the reducing agent for glass according to claim 1 or 2.

10. A method for producing glass containing metal microparticles as described in claim 9, wherein the glass-containing raw material is a raw material containing at least one type selected from the group consisting of glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components.

11. The method for producing glass containing metal fine particles according to claim 9, wherein the treatment temperature in the reduction treatment is 1300°C to 1800°C.

12. The method for producing metal fine particle-containing glass according to claim 9, wherein the number density of the metal fine particles for each particle size in an arbitrary cross section of the metal fine particle-containing glass is in the following range, and the area ratio of the metal fine particles in the arbitrary cross section to the total area is 0 to 0.10%: Particle size greater than 1 μm and equal to or less than 5 μm: 0 to 500 particles / mm ２ Particle size exceeding 5 μm and 10 μm or less: 0 to 30 particles / mm ２ Particle size more than 10 μm and less than 100 μm: 0 to 5 pieces / mm ２ Particle size exceeding 100 μm and 500 μm or less: 0 to 0.5 particles / mm ２ Particle size over 500 μm: substantially not contained 13. The metal particle-containing glass has a visible light transmittance Tv at a thickness of 2 mm and a transmittance T at a wavelength of 1100 nm. １１００ The absolute value of the difference ABS (Tv-T １１００ 10. The method for producing metal fine particle-containing glass according to claim 9, wherein the content of ZnO in the glass is 30% or less.

14. The method for producing metal fine particle-containing glass according to claim 9, wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb.

15. The total content of network-forming oxides contained in the glass-containing raw material, calculated as mass% on an oxide basis (NWF) ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total NWM of the contents of network modifier oxides contained in the glass-containing raw material is ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ 10. The method for producing metal fine particle-containing glass according to claim 9, wherein is 0.60 to 2.

00.

16. Average Fe content in the metal particle-containing glass ２ O ３ 10. The method for producing metal fine particle-containing glass according to claim 9, wherein the concentration is 0.001% to 0.5% in mass % on the oxide basis.

17. Glass containing metal fine particles, wherein the number density of the metal fine particles for each particle size in an arbitrary cross section is within the following range, and the area ratio of the metal fine particles in the arbitrary cross section to the total area is 0 to 0.10%. Particle size from 1 μm to less than 5 μm: 0–500 particles / mm ２ Particle size between 5μm and 10μm: 0–30 particles / mm ２ Particle size between 10 μm and 100 μm: 0–5 particles / mm ２ Particle size between 100μm and 500μm: 0–0.5 particles / mm ２ Particle size 500μm or higher: Contains しない of pure substance 18. The metal fine particle-containing glass according to claim 17, which is obtained by melting a glass-containing raw material and reducing the resulting molten material with a glass reducing agent containing SiC.

19. The metal particle-containing glass according to claim 17, wherein the glass-containing raw material is a raw material containing at least one selected from the group consisting of glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components.

20. Visible light transmittance Tv at a thickness of 2 mm and transmittance T at a wavelength of 1100 nm １１００ The absolute value of the difference ABS (Tv-T １１００ 18. The metal fine particle-containing glass according to claim 17, wherein the ratio of ZnO to ZnO is 30% or less.

21. The metal fine particle-containing glass according to claim 17 or 18, wherein the metal fine particles contain at least one element selected from the group consisting of Fe, Si, Co, Cr, Ni, Ti, P, Sb, W, and Nb.

22. The sum of the contents of network-forming oxides contained in glass-containing raw materials, calculated as a percentage by mass on an oxide basis (NWF) ｂｅｆｏｒｅ and the total content NWF of network-forming oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWF ａｆｔｅｒ／ｂｅｆｏｒｅ is 0.40 to 1.50, and the total content NWM of network modifier oxides contained in the glass-containing raw material ｂｅｆｏｒｅ and the total NWM of the contents of network modifier oxides in the metal fine particle-containing glass. ａｆｔｅｒ Ratio of NWM ａｆｔｅｒ／ｂｅｆｏｒｅ The metal fine particle-containing glass according to claim 17 or 18, wherein is 0.60 to 2.

00.

23. Average Fe in the metal fine particle-containing glass ２ O ３ 19. The metal fine particle-containing glass according to claim 17, wherein the concentration is 0.001% to 0.5% in mass % on an oxide basis.

24. A method for recycling glass, comprising: melting a glass-containing raw material containing at least one selected from glass containing foreign matter, glass containing coloring components, and glass containing unnecessary components to obtain a molten material; and reducing the molten material using the glass reducing agent according to claim 1 or 2.

25. The method for recycling glass according to claim 24, further comprising subjecting the melt to an oxidation treatment.

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