How to dispose of glass waste

Abstract

A method for producing an inorganic material suitable for use as a raw material in a glass melting process. The method includes: - supplying a mixture of vitrifiable materials, including recycled materials, including organic matter, to a main vessel; - melting the mixture of vitrifiable materials in the main vessel using an immersion burner to obtain a bath of molten material; and - introducing a solid oxidizer into the bath of molten material.

Description

[Technical Field]

[0001] The present invention relates to a method for treating glass waste, and more particularly to a method for recycling glass-based materials having a significant proportion of organic matter to form inorganic materials suitable for use as vitrifiable raw materials in glass melting processes. DETAILED DESCRIPTION OF THE INVENTION

[0002] It is known to recycle glass waste containing organic components by reintroducing them into a process for producing glass products. However, the presence of organic compounds can affect the quality and / or melting of the resulting glass. Typically, prior removal of organic components, for example by combustion, is carried out before the raw materials are fed into the melting furnace. Recently, the development of submerged burners has made it possible to omit this step. In fact, melting with a submerged burner allows the combustion of organic components that are introduced into the center of the molten glass together with the raw materials to be recycled. However, it has been found that the glass obtained by this method can have poor quality, especially due to the presence of inclusions of carbon particles.

[0003] It has also been found that directly recycling organic-containing glass waste in processes for manufacturing glass products tends to disrupt the melting and forming conditions of the product, which has the effect of limiting the amount of waste that can be introduced into these processes.

[0004] In order to improve the efficiency of recycling glass waste containing organic matter, the present invention proposes a method for producing inorganic materials, such as cullet, which have sufficient quality to be used as raw material in glass melting processes without significantly disturbing the conditions for melting or forming the glass.

[0005] Thus, a first aspect of the present invention relates to a method for producing an inorganic material suitable for use as a raw material in a glass melting process, the method comprising: - feeding the main tank with a mixture of vitrifiable materials, including recycled materials, including organic matter; - melting the mixture of vitrifiable materials in the main tank using an immersion burner to obtain a melt; and - Introducing a solid oxidizer into the melt.

[0006] The use of an immersion burner has the advantages of both providing a large amount of oxygen to the center of the melt and thoroughly stirring the melt, thereby promoting homogenization of the mixture and decomposition of any contaminants. However, this has proven insufficient, especially when recycling glass-based materials containing large amounts of organic matter. Even when providing a large amount of oxygen, the inorganic materials produced have a large amount of carbon particles resulting from the partial combustion of the organic compounds. Similarly, it has been found that it is impossible to control or reduce the redox of the inorganic materials produced solely through the use of an immersion burner. It has been found that inorganic materials with high redox tend to generate foam on the surface of the glass bath when used in melting processes. Without wishing to be bound by any theory, it is hypothesized that ferrous iron (FeO) reacts with sulfates contained in certain raw materials (e.g., flat glass cullet) to produce SO2 gas, which then forms foam on the surface of the glass bath. The presence of this foam layer reduces the efficiency of the furnace's energy transfer.

[0007] It has been found that the combined use of an immersion burner and a solid oxidizer makes it possible to significantly improve the quality of the inorganic material produced, in particular by significantly reducing or avoiding the presence of carbon particles in the inorganic material produced, so that this inorganic material can be used in the glass melting process without risk of disturbance thereof.

[0008] The vitrifiable material mixture typically contains at least 50% by weight, preferably at least 70% by weight, more preferably at least 80% by weight, or even at least 90% by weight of recycled material. Traditional raw materials, particularly those derived from natural resources, can be added to the vitrifiable material mixture, particularly to adjust the composition of the inorganic material produced. In one embodiment, the vitrifiable material mixture is composed of 100% recycled material. Examples of recycled materials that can be used in the method of the present invention include glass- or ceramic-based organic-containing recycled materials, such as waste fiber or mineral wool (particularly bound by organic binders), household cullet, which is often contaminated with organic waste, and laminated glass waste. In certain embodiments, the vitrifiable material mixture can be derived from a single recycled material source, particularly mineral wool waste, glass fiber waste, or laminated glass waste. Typically, the vitrifiable material mixture contains at least 1% by weight, preferably at least 2% by weight, and more preferentially at least 5% by weight of organic matter, based on the total weight of the vitrifiable material mixture, and typically at most 30% by weight, or at most 25% by weight, or at most 20% by weight. The amount of organic matter can be determined by measuring the loss on ignition at 650°C (the change in mass, expressed as a percentage by weight of the dry matter, obtained by heating to 650°C). A large amount of organic matter has the advantage that, through its combustion, it contributes to providing the energy required to melt the vitrifiable material mixture, thus allowing the amount of fuel supplied by the burner to be reduced. Recycled materials may also contain metal contaminants, such as iron or copper, particularly from construction waste. Thus, the raw material mixture may contain at least 0.2% by weight, or at least 0.5% by weight, of metal particles.

[0009] The chemical composition of the vitrifiable material mixture, expressed in oxide form, is not particularly limited. It may in particular contain a high iron content, typically greater than 2% by weight, preferably greater than 3% by weight, or greater than 4% by weight, and preferably less than 10% by weight, or less than 8% by weight, of total iron, expressed in the form of Fe2O3. It may also be a composition with a low iron content, typically less than 2% by weight, preferably less than 1.7% by weight, more preferentially less than 1.5% by weight, or less than 1% by weight, of total iron, expressed in the form of Fe2O3. In fact, it has been found that the lower the iron content, the more difficult it is to control the redox state of the inorganic material produced. The method according to the present invention allows for easier suppression of the redox state of the inorganic material produced, including compositions with a low iron content.

[0010] In certain embodiments, the vitrifiable material mixture can have a composition containing the following components, in weight percentages based on the inorganic portion of the vitrifiable material mixture, defined by the following distinct ranges: SiO2 35~80%, Al2O30-30%, CaO+MgO 2~35%, Na2O+K2O 0~30%. Here, the total content of SiO2 and Al2O3 is typically 50 to 80 mass %.

[0011] Preferably, the mixture of vitrifiable materials has a composition containing the following components, in mass proportions based on the inorganic portion of the mixture of vitrifiable materials, which are defined by the following ranges: SiO2 50-75%, Al2O30-8%, CaO+MgO 2~20%, Fe2O3 0~2%, Na2O+K2O 12-20%. B2O3 0-10%.

[0012] The mixture of vitrifiable materials is preferably introduced into the main tank using a batch feeder. The feed is advantageously deep feed, i.e., the feed of the mixture of vitrifiable materials is below the level of the melt. Examples of batch feeders for deep feed are described, for example, in WO 2012 / 132184.

[0013] The main tank constitutes a furnace equipped with submerged burners, which is often designated by the name SBM (Submerged Burner Melter) or SCM (Submerged Combustion Melter). The main tank may be a refractory-walled tank conventionally used in glass melting. Alternatively, the main tank may be a so-called water-jacketed tank, which includes bare metal walls, i.e., is not protected by refractory material, and is traversed by a system of internal pipes through which a coolant, e.g., water, circulates. The main tank contains one or more submerged burners. An example of a submerged burner melter suitable for the present invention is described in WO 2013 / 186480.

[0014] "Immersion burner" means a burner configured so that the flame it generates occurs within the melt. They are usually positioned so that they are flush with the bottom. Immersion burners used in the context of the present invention may be of cylindrical shape, as shown for example in Figure 5 of WO 99 / 35099, or of linear shape, as described for example in WO 2013 / 117851.

[0015] The submerged burner is supplied with fuel and oxidizer. The oxidizer supplied to the submerged burner is gaseous and preferably contains at least 80% oxygen by volume. This is typically oxygen-enriched air or pure oxygen. The fuel supplied to the submerged burner, typically gaseous, is usually natural gas. The fuel / oxidizer mixture may be a lean fuel mixture, which has a stoichiometric oxygen / fuel molar ratio. The excess oxygen may contribute in part to the oxidation of organic matter contained in the vitrifiable material mixture. Alternatively, at least a portion of the oxygen can be provided by a separate bubbler for the submerged burner. The bubbler is also typically located at the bottom of the main tank. The ratio of the volumetric flow rate of oxygen to the volumetric flow rate of fuel gas is typically at least 2, preferably 2.1 to 3.5.

[0016] However, it was observed that even with high oxygen stoichiometry it was not possible to eliminate the presence of carbon particles during the melting of raw materials containing a large amount of organic matter. The addition of a solid oxidizer in combination with melting using a submerged burner, preferably with an excess of oxygen due to a superstoichiometric supply of oxygen to the submerged burner, or the introduction of oxygen using an oxygen bubbler, makes it possible to overcome this drawback.

[0017] The solid oxidizer is typically in powder or granular form and can be selected from nitrates, particularly sodium nitrate; sulfates, particularly sodium sulfate or calcium sulfate (all in their hydrated form); potassium dichromate; peroxides, particularly potassium peroxide or calcium peroxide; cerium oxide; and manganese oxides, particularly manganese dioxide (MnO), manganese(III) oxide (MnO), manganese(II, III) oxide (MnO), and permanganates (especially of sodium, potassium, calcium, or magnesium). Preferably, the solid oxidizer is selected from manganese oxides, particularly manganese dioxide. It may optionally be provided in the form of a chemical product, an ore, or by recycling materials, particularly plaster-based materials in the case of calcium sulfate. In certain embodiments, the solid oxidizer is not selected from sulfates. Indeed, their use as oxidizers increases sulfur oxide (SOx) emissions in flue gases, which should be avoided from an environmental point of view and involves expensive treatment facilities.

[0018] The solid oxidizer can be added directly to the main tank. It can therefore be introduced as a mixture with the vitrifiable material mixture. Alternatively, it can be introduced by a separate batch feeder located on the side wall of the main tank.

[0019] In a preferred embodiment, the method according to the present invention includes transferring the melt from a main tank to an auxiliary tank, and the solid oxidizer is introduced downstream of the main tank. Thus, the solid oxidizer can be introduced during the transfer of the melt, typically into a feeder channel of the auxiliary tank, e.g., by a batch injector located in a segment of the feed channel. Alternatively, the solid oxidizer can be introduced directly into the auxiliary tank, e.g., by a batch injector located in a sidewall of the auxiliary tank.

[0020] Regardless of how the solid oxidizer is introduced, it is usually added at a concentration of 0.5 to 8% by weight, preferably 1 to 5% by weight, relative to the flow rate of the vitrifiable material mixture. The introduction of the solid oxidizer can be carried out continuously or intermittently. In the case of intermittent introduction, the amount added is expressed as an average amount relative to the average residence time of the melt in the tank to which the oxidizer is added.

[0021] The nature of the auxiliary tank is not particularly limited. It may be a tank with a refractory wall or a tank called a water jacket. It typically includes heating means, which may be selected from electrodes, overhead burners, immersion burners, or a combination thereof. The melt is preferably maintained at a temperature of 1000 to 1300°C, preferably 1050 to 1250°C.

[0022] The auxiliary tank advantageously includes means for stirring the melt. These can typically be selected from bubblers, mechanical mixers, or immersion burners, which supply air, oxygen-enriched air, or oxygen. The stirring means allow for a uniform mixture of the solid oxidizer in the melt and, in particular, create a zone of intense stirring within the auxiliary tank. Therefore, the auxiliary tank according to the present invention is not suitable for refining. In a preferred embodiment, the auxiliary tank includes one or more immersion burners. Indeed, it has surprisingly been observed that the use of burners immersed in the auxiliary tank allows for both better control of the redox of the inorganic material formed and the achievement of lower redox values. Without wishing to be bound by any theory, it is hypothesized that the stirring caused by the immersion burners allows for improved homogenization of the solid oxidizer and promotes a rapid reaction between the solid oxidizer and the melt.

[0023] The method according to the invention makes it possible to obtain inorganic materials, typically cullet, derived from recycled materials, with higher quality in terms of limiting the amount of carbon particles and controlling the redox.

[0024] The method according to the invention makes it possible to obtain inorganic materials, typically cullet, derived at least in part from recycled materials, which have a higher quality in terms of limiting the amount of carbon particles and controlling the redox.The invention therefore also relates to inorganic materials which can be used as raw materials in glass melting processes and which can be obtained by the method according to the invention, which are derived at least in part from recycled materials containing organic matter and which are essentially free of carbon particles.

[0025] The inorganic material according to the present invention is preferably cullet, mainly derived from recycled materials (typically at least 50% by weight, preferably at least 70% by weight, more preferentially at least 80% by weight, or even at least 90% by weight), intended to be used as raw material in a melting process. It may be hot cullet in liquid form (typically a bath of molten glass) or cold cullet in solid form (typically crushed or granular glass particles).

[0026] The inorganic material according to the present invention is essentially free of carbon particles. In this respect, it typically has a total carbon content of less than 0.1%, preferably less than 0.05%, or even less than 0.01%. The total carbon content is determined by melting the inorganic material under a dioxygen atmosphere, typically at 1300°C, and measuring the amount of carbon dioxide released by infrared spectroscopy.

[0027] The inorganic material typically has a redox of less than 0.95, preferably less than 0.9, more preferentially less than 0.7, or even less than 0.5, for example, 0.1, 0.15, or 0.2 to 0.9, or 0.7, or 0.5, for example, 0.1 to 0.9 or 0.2 to 0.7. In a particular embodiment, the inorganic material may have a redox of 0.3, or 0.5 to 0.9, or 0.7. In another embodiment, the inorganic material may have a redox of 0.1, or 0.15 to 0.5, or 0.3. The redox is determined by the ferrous content (Fe) expressed as Fe2O3. 2+ ) to the total iron content expressed as Fe2O3.

[0028] Typically, the inorganic material has a volume fraction of bubbles of at least 0.05. The volume fraction of bubbles B is determined by the formula B=1−(ρ バルク / ρ ガラス ) according to the density of the glass, ρ ガラス apparent density ρ of glass block バルク This can be determined by evaluating:

[0029] Typically, the inorganic material has a composition comprising the following components in mass proportions, which are defined by the following ranges: SiO2 35~80%, Al2O30-30% CaO+MgO 2~35%, Na2O+K2O 0~30%. Here, the total content of SiO2 and Al2O3 is preferably 50 to 80 mass %.

[0030] Preferably, the inorganic material has a composition that typically includes the following components in weight proportions defined by the following ranges: SiO2 50-75%, Al2O30-8%, CaO+MgO 2~20%, Fe2O3 0~2%, Na2O+K2O 12-20%. B2O3 0-10%.

[0031] By limiting the amount of carbon particles and controlling the redox, the inorganic material according to the invention can be advantageously used as a raw material in glass melting processes, especially electric melting, without risk of disturbances, in particular by avoiding foaming in the presence of raw materials containing sulfates and by limiting the increase in melting temperature.

[0032] The present invention further relates to a method for producing mineral wool, the method comprising providing a melt to be fiberized and fiberizing the melt to be fiberized, wherein the melt to be fiberized is at least partially derived from an inorganic material according to the present invention or obtained by a method for producing an inorganic material according to the present invention. In certain embodiments, the step of providing a melt comprises providing a mixture of raw material(s) and, if appropriate, melting the mixture of raw material(s) to obtain a melt to be fiberized, the mixture of raw material(s) comprising at least 20% by weight, preferably at least 50% by weight, even at least 70% by weight, or even at least 80% by weight of the inorganic material according to the present invention or the inorganic material obtained by the method for producing an inorganic material according to the present invention. In certain embodiments, the mixture of raw material(s) and the resulting melt to be fiberized essentially consist of the inorganic material according to the present invention. The melt to be fiberized may be hot cullet directly derived from a method for producing an inorganic material according to the present invention. In this case, the method for producing mineral wool comprises producing an inorganic material according to the above method, wherein the inorganic material is a molten inorganic material, and fiberizing the molten inorganic material. In particular, the inorganic material is preferably conveyed to the fiberizing element at the outlet of the auxiliary tank. Alternatively, the melt can be obtained by melting low-temperature cullet resulting from the method for producing inorganic material according to the present invention. In this case, the method for producing mineral wool comprises the steps of producing an inorganic material according to the above-described method, wherein the inorganic material is a solid inorganic material, melting the solid inorganic material to obtain a melt to be fiberized, and fiberizing the melt to be fiberized.

[0033] Fiberization can be carried out by any method known to those skilled in the art, in particular by external or internal centrifugal fiberization. External centrifugal methods typically use a cascade of centrifugal wheels to which the melt to be fiberized is supplied by a distributor, as described, for example, in applications EP 0 465 310 or EP 0 439 385. In internal centrifugal methods, the melt stream to be fiberized is introduced into a fiberization dish, which rotates at high speed and is perforated around its periphery with a large number of orifices, through which the glass is released in the form of filaments due to the effect of centrifugal force. These filaments are then subjected to the action of a high-temperature, high-velocity annular tensile flow that travels along the spinner wall, which attenuates the filaments and converts them into fibers. Fiberization is preferably carried out internally, in particular using a fiberization element as described in application FR 1 382 917.

[0034] Finally, the present invention relates to mineral wool obtained directly from the inorganic material according to the present invention or from the inorganic material obtained by the method for producing an inorganic material according to the present invention. In other words, the mineral wool is obtained from a melt composed of the inorganic material according to the present invention or the inorganic material obtained by the method for producing an inorganic material according to the present invention. Therefore, the mineral wool according to the present invention has the same composition as the inorganic material according to the present invention. Therefore, the characteristics of the composition (such as total carbon content and redox) described for the inorganic material also apply to the mineral wool according to the present invention. In particular, the mineral wool according to the present invention is characterized by being at least partially derived from recycled materials containing organic matter and being essentially free of carbon particles. [Example]

[0035] The invention is illustrated by the following non-limiting examples.

[0036] In each of the following examples, a mixture of vitrifiable materials consisting of 100% ground mineral wool waste containing 8% by weight of organic compounds is introduced into an immersion burner furnace using a batch charger.

[0037] The first series of examples (C1, I1 and I2) are 0.5m 2 The furnaces are manufactured in an SBM furnace containing a main tank with a refractory surface (R) and a 150 kW immersion burner supplied with an oxygen / natural gas mixture with a volumetric flow ratio of oxygen to natural gas of 2.5. In these three examples, the main tank is refractory to 30 Nm 3 The furnace further includes an oxygen bubbler that supplies an oxygen flow rate of 10 t / h. The furnace withdrawal rate is 10 t / d.

[0038] The second series of examples (C2, I3 and I4) are 0.3 m 2 The coal is produced in an SBM furnace containing a main tank with a refractory wall called a water jacket (WJ) with a surface area of ​​1.5 t / day, and three 110 kW immersion burners fed with an oxygen / natural gas mixture with a volumetric flow ratio of oxygen to natural gas of 2.5. The furnace withdrawal rate is 3 t / d.

[0039] In Example I1 according to the invention, manganese oxide (MnO2) is mixed with ground mineral wool and introduced into the main tank.

[0040] In Examples I2 to I4 according to the present invention, the melt obtained at the outlet of the main tank is transferred to an auxiliary tank, and manganese oxide (MnO2) is introduced through a feeder channel in the auxiliary tank. In Example I2, the auxiliary tank is a fire-resistant tank (R) equipped with an immersion burner similar to that of the main tank. In Example I3, the auxiliary tank is a fire-resistant tank (R) equipped with an air burner and bubbler on the melt flow path. In Example I4, the auxiliary tank is a so-called water-jacketed tank (WJ) equipped with an immersion burner similar to that of the main tank.

[0041] In each of Examples I1 to I4, manganese oxide was introduced at a draw rate of 2% by weight, which was a mass flow rate of 8.3 kg / h for I1 and I2, and 2.5 kg / h for I3 and I4.

[0042] Examples C1 and C2 are comparative examples in which no solid oxidizer was introduced.

[0043] The melt is recovered in the form of cullet at the outlet of the main tanks (C1, C2 and I1) or the auxiliary tanks (I2, I3 and I4). The cullet composition produced and its properties are summarized in Table 1.

[0044] The presence of carbon particles is determined by visual observation: A "+" indicates the presence of carbon particles visible to the naked eye, and a "-" indicates the absence of carbon particles visible to the naked eye.

[0045] The total amount of carbon is determined by melting the inorganic material at 1300° C. in a dioxygen atmosphere and measuring the amount of carbon dioxide released by infrared spectroscopy.

[0046] The redox is determined by wet FeO analysis. [Table 1]

[0047] Compared to the cullets obtained in Examples C1 and C2, the cullets of Examples I1 to I3 according to the invention are found to be of better quality, not only because they are essentially free of carbon particles, but also because of better control of redox. In particular, by introducing the oxidant downstream of the main tank, as in Examples I2 to I4, it is possible to adjust the desired redox to a relatively low value, depending on the amount of oxidant introduced. The present disclosure includes the following inventive aspects: <Aspect 1> 1. A method for producing an inorganic material suitable for use as a raw material in a glass melting process, comprising: - feeding the main tank with a mixture of vitrifiable materials, including recycled materials, including organic matter; - melting the mixture of vitrifiable materials in the main tank using an immersion burner to obtain a melt; and - introducing a solid oxidant into said melt; A method comprising: <Aspect 2> The chemical composition of the mixture of vitrifiable materials, expressed in oxide form, contains less than 2% by weight, preferably less than 1% by weight, of Fe 2 O 3 2. The method of embodiment 1, comprising: <Aspect 3> The chemical composition of the mixture of vitrifiable materials, expressed in the form of oxides, is 2 to 10% by weight of Fe 2 O 3 2. The method of embodiment 1, comprising: <Aspect 4> Aspect 4. The method of any one of aspects 1-3, wherein the recycled material is selected from mineral wool waste, household cullet, and laminated glass waste. <Aspect 5> Aspect 5. The method of any one of aspects 1 to 4, wherein the solid oxidizing agent is selected from nitrates, particularly sodium nitrate, sulfates, particularly sodium sulfate or calcium sulfate, and manganese oxides, particularly manganese dioxide. <Aspect 6> Aspect 6. The method of any one of aspects 1-5, wherein the method comprises transferring the melt from the main tank to an auxiliary tank, and wherein the solid oxidant is introduced downstream of the main tank. <Aspect 7> Aspect 6. The method of any one of aspects 1 to 5, wherein the auxiliary tank comprises an agitation means, such as a bubbler, a mixer, or an immersion burner. <Aspect 8> 8. An inorganic material that can be used as a raw material in a glass melting process, obtainable by the method according to any one of aspects 1 to 7, wherein the inorganic material is produced at least in part from recycled materials, including organic matter, and is essentially free of carbon particles. <Aspect 9> 9. The inorganic material of embodiment 8, wherein the inorganic material is cullet. <Aspect 10> 10. The inorganic material of any one of embodiments 8 or 9, having a total carbon content of less than 0.1%. <Aspect 11> 11. The inorganic material according to any one of aspects 8 to 10, having a redox of 0.1 to 0.9, preferably 0.2 to 0.7. <Aspect 12> 12. A method for producing mineral wool, comprising: providing a melt to be fiberized; and fiberizing the melt to be fiberized, wherein the melt to be fiberized is at least partially produced from the inorganic material according to any one of aspects 8 to 11 or obtained by the method according to any one of aspects 1 to 7. <Aspect 13> 12. A mineral wool obtained directly from the inorganic material according to any one of aspects 8 to 11 or from inorganic material obtained by the method according to any one of aspects 1 to 7, wherein the mineral wool is produced at least in part from recycled materials comprising organic matter, and wherein the mineral wool is essentially free of carbon particles. <Aspect 14> 14. The mineral wool of embodiment 13, having a total carbon content of less than 0.1%. <Aspect 15> 15. The mineral wool according to aspect 13 or 14, having a redox of 0.1 to 0.9, preferably 0.2 to 0.7.

Claims

1. 1. A method for producing an inorganic material suitable for use as a raw material in a glass melting process, comprising: - feeding the main tank with a mixture of vitrifiable materials containing recycled materials, including organic matter; - melting the mixture of vitrifiable materials in the main tank using an immersion burner to obtain a melt; and - introducing a solid oxidizing agent into the melt; A method comprising:

2. The chemical composition of the mixture of vitrifiable materials, expressed in the form of oxides, is less than 2% by weight, preferably less than 1% by weight, of Fe ２ O ３ 2. The method of claim 1, wherein the total iron oxide is expressed in the form:

3. The chemical composition of the mixture of vitrifiable materials, expressed in the form of oxides, is: 2 to 10% by weight of Fe ２ O ３ 2. The method of claim 1, wherein the total iron oxide is expressed in the form:

4. The method according to any one of claims 1 to 3, wherein the recycled material is selected from mineral wool waste, household cullet, and laminated glass waste.

5. 5. The method according to any one of claims 1 to 4, wherein the solid oxidizing agent is selected from nitrates, in particular sodium nitrate, sulfates, in particular sodium sulfate or calcium sulfate, and manganese oxides, in particular manganese dioxide.

6. 6. The method of any one of claims 1 to 5, wherein the method comprises transferring the melt from the main tank to an auxiliary tank, and wherein the solid oxidizer is introduced downstream of the main tank.

7. 7. The method of claim 6, wherein the auxiliary tank includes an agitation means such as a bubbler, mixer, or immersion burner.

8. A method described in any one of claims 1 to 7, wherein the inorganic material is essentially free of carbon particles.

9. The method according to any one of claims 1 to 8, wherein the inorganic material is cullet.

10. The method of claim 1, wherein the inorganic material has a total carbon content of less than 0.1%.

11. The method according to any one of claims 1 to 10, wherein the inorganic material has a redox of 0.1 to 0.9, preferably 0.2 to 0.

7.

12. 12. A method for producing mineral wool, comprising: providing a melt to be fiberized; and fiberizing the melt to be fiberized, wherein the melt to be fiberized is at least partially produced from an inorganic material obtained by the method according to any one of claims 1 to 11.

13. 13. The method of claim 12, wherein the mineral wool is essentially free of carbon particles.

14. The method described in claim 12 or 13, wherein the mineral wool has a total carbon content of less than 0.1%.

15. A method according to any one of claims 12 to 14, wherein the mineral wool has a redox of 0.1 to 0.9, preferably 0.2 to 0.7.

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