Melting and fiberization of calcine containing metallic residues

Abstract

The present invention relates to a raw material composition adapted for melting and fiberizing by external centrifugation to obtain mineral wool, characterized in that it comprises from 1 to 99% by mass of cullet including a glass fraction and 0.001 to 20% by mass of metallic residues. The present invention also relates to a process for producing glass using such a raw material composition, as well as the glass obtained by such a process. The present invention also relates to a process for manufacturing mineral wool using such a raw material composition, as well as mineral wool obtained by such a process.

Description

Title of the invention: Melting and fiberization of calcine comprising metallic residues

[0001] The present invention relates to a raw material composition adapted for use in a glass furnace, where it is melted and then fiberized by external centrifugation, comprising cullet containing metallic residues. Also related are the processes for melting and external centrifugal fiberizing this composition, as well as the glass and mineral wool obtained by these processes.

[0002] It is known to "recycle" cullet by melting it in a glass furnace to form new glass or to fiber it. Among the many advantages of such cullet recycling are the improved energy efficiency of the glass furnace, as the mixture of raw materials including cullet is easier to melt than a "conventional" composition of raw materials containing, among other things, large quantities of silica.

[0003] However, depending on its origin, cullet may contain impurities that make recycling in a conventional glass furnace difficult or even impossible. This is particularly true of cullet containing metallic impurities. The metal equipment of conventional glass furnaces, for example platinum thermocouples, is not compatible with the metallic impurities present in such cullet. Furthermore, under oxidizing conditions, metallic elements can reduce the oxides present in the glass mixture and thus affect the quality of the final glass, especially its transparency. Moreover, due to their density, metallic elements can become trapped at the bottom of the furnace and generate a conductive layer that can either rapidly wear down the refractories or be released during production, thereby causing defects or machine breakdowns.

[0004] Among cullet containing metallic impurities, photovoltaic cullet can be cited. This cullet, derived from used photovoltaic panels, is contaminated by metallic elements constituting the photosensitive cells, such as silicon, by conventional metallic pollutants such as aluminum, or by metallic elements from components used in thin-film technologies, such as tellurium, cadmium, indium, or silver. Currently, the various components of photovoltaic panels are separated from one another and then recycled individually. This is a complex and costly process. Reinforced glass, which is glass cast around a metallic framework, generally made of steel, is also difficult to recycle.

[0005] Thus, there remains a real need to develop a melting process enabling the recycling of a cullet containing metallic residues. Summary of the invention

[0006] In this context, the inventors have developed a process for recycling cullet containing metallic residues by incorporating such cullet into raw material compositions that can be melted in a furnace configured to stratify the molten raw materials by density and to draw off the densest molten raw materials, including metallic residues, from its lower section. This type of furnace is particularly effective for melting raw material compositions suitable for external centrifugal fiberization.

[0007] The inventors have shown that recycling a cullet containing metallic residues, which are therefore in reduced form, in this type of furnace was possible despite the changes in viscosity and chemistry of the mixture that such reduced components can cause.

[0008] In addition to enabling the reuse of cullet, which is usually difficult to recycle, the solution proposed by this invention also has the advantage of being economical and environmentally friendly. Indeed, mineral wools are usually manufactured from natural raw materials, such as feldspar, dolomite, and lime, which are expensive and / or emit CO2 and / or negatively impact the material yield of the glass composition during melting. The use of cullet therefore reduces the use of these raw materials. Furthermore, the lower quantities of CO2 and water emitted during the manufacture of mineral wool using this cullet improve the material yield, that is, the ratio between the quantity of raw materials used and the quantity of molten glass obtained after melting the raw material composition.The use of cullet also reduces the energy required to melt the raw material composition.

[0009] Thus, the present invention relates to a composition of raw materials adapted to be melted and fiberized by external centrifugation to obtain a mineral wool, characterized in that it comprises from 1% to 99% by mass of a cullet comprising:

[0010] - a fraction of glass and

[0011] - 0.001 to 20% by mass of metallic residues.

[0012] In some embodiments, the raw material composition comprises from 2 to 70%, preferably from 2% to 50%, or even from 4 to 20%, or from 5 to 15%, by mass of said calcin.

[0013] In certain embodiments, the glass fraction of said cullet has a chemical composition comprising, in mass percentage:

[0014] - SiO2: from 50 to 80%,

[0015] - Na2O: from 3 to 20%,

[0016] - CaO: from 3 to 20%,

[0017] - MgO: from 0 to 10%,

[0018] - A12O3: from 0 to 5%,

[0019] - K2O: from 0 to 10%, and

[0020] - Fe2O3: from 0 to 15%.

[0021] In certain embodiments, said calcin comprises from 0.01 to 15%, for example from 0.1% to 10%, or even 1 to 4%, by mass of metallic residues.

[0022] In some embodiments, the metallic residues comprise one or more elements selected from: Si, Al, Fe, Te, Cd, In, Cu, Pb, Ta, Ag, Sc, Y, and a lanthanide.

[0023] In certain embodiments, said calcin has a loss on ignition, after drying, of 0.001% to 20%.

[0024] In certain embodiments, said mineral wool has a chemical composition comprising, in mass percentages:

[0025] SiO2: 30 to 75%,

[0026] A12O3: 0 to 30%,

[0027] CaO+MgO: 5 to 45%,

[0028] Na2O+K2O: 0 to 20%,

[0029] Fe2O3: 0 to 20%,

[0030] B2O3: 0 to 14%.

[0031] In certain embodiments, said mineral wool has a chemical composition comprising, in mass percentages:

[0032] SiO2: 30 to 50%,

[0033] A12O3: 10 to 24%,

[0034] CaO+MgO: 20 to 45%,

[0035] Fe2O3: 0 to 20%,

[0036] Na2O+K2O: 0 to 10%, and

[0037] B2O3: 0 to 1%.

[0038] In certain embodiments, said calcin is in the form of a conformed composite formed from a mixture comprising:

[0039] - from 1 to 99%, preferably from 1 to 25%, or even from 5 to 20%, by mass of said calcin comprising from 0.001 to 20% by mass of metallic residues,

[0040] - from 1 to 40%, preferably from 2 to 20%, or even from 10 to 20%, by mass of a binder, and

[0041] - from 0 to 98%, preferably from 55 to 97%, or even from 60 to 85%, by mass of charges minerals,

[0042] in relation to the total dry weight of said mixture.

[0043] The present invention also relates to a method for producing a glass comprising the following steps:

[0044] a) feeding a melting chamber with a composition of raw materials as defined in this application, as a vitrifiable feedstock, and

[0045] b) the melting of said composition of raw materials in said melting chamber, to obtain a bath of molten material.

[0046] In certain embodiments of the glass production process, the melting chamber is a vertical furnace configured to stratify the molten raw materials according to their density. Preferably, the melting chamber is a cupola furnace.

[0047] Another object of the present invention is a glass obtained by the production process as defined in this application.

[0048] Another object of the present invention is a method for manufacturing mineral wool, comprising the following steps:

[0049] a) feeding a melting chamber with a composition of raw materials as defined in this application, as a vitrifiable feedstock,

[0050] b) melting said composition of raw materials in said melting chamber, to obtain a bath of molten material, and

[0051] c) the fiberization of said molten material bath.

[0052] In certain embodiments of the process for manufacturing mineral wool, the melting chamber is a vertical furnace configured to stratify the molten raw materials according to their density. Preferably, the melting chamber is a cupola furnace.

[0053] Another object of the present invention is a mineral wool obtained by the manufacturing process as defined in this application. DETAILED DESCRIPTION

[0054] The raw material composition according to the invention is adapted to be melted and fibered by external centrifugation in order to obtain mineral wool.

[0055] According to the invention, a raw material composition is suitable for external centrifugal fiberization when the temperature (TLogl) of the glass bath, for a dynamic viscosity Log 1, is between 1390 °C and 1490 °C, and the temperature difference (TLogl - Tlog3) between the temperatures corresponding to the viscosities Log 1 and Log 3 is between 320 °C and 390 °C. As is known in the field of glass melting, dynamic viscosity is expressed in N Log Poises, which corresponds to 10 N Poises (0.1 Pa·s), each viscosity value corresponding to a given temperature of the glass bath. Dynamic viscosity can be measured using a viscometer suitable for glass. Dynamic viscosity can also be determined by calculation, in particular using the Fluegel model. (A. Fluegel, “Glass Viscosity Calculation Based on a Global Statistical Modeling Approach”, Glass Technol.: Europ. J. Glass Sci. Technol. A, vol. 48, 2007, no. 1, p 13-30).

[0056] Mineral wool is characterized by an entanglement of discontinuous fibers, which distinguishes it from continuous fibers generally intended for the reinforcement of organic or inorganic materials (for example cement).

[0057] For the purposes of the invention, a mineral wool has a chemical composition comprising the following constituents:

[0058] SiO2: 30 to 75% by mass,

[0059] Al2O3: 0 to 30% by mass,

[0060] CaO+MgO: 5 to 45% by mass,

[0061] Na2O+K2O: 0 to 20% by mass,

[0062] Fe2O3: 0 to 20% by mass,

[0063] B2O3: 0 to 14% by mass.

[0064] The term rock wool generally refers to mineral wools having fibers whose chemical composition includes the following constituents:

[0065] SiO2: 30 to 50% (for example 40 to 48%) by mass,

[0066] Al2O3: 10 to 24% (for example 14 to 21%) by mass,

[0067] CaO+MgO: 20 to 45% (for example 24 to 33%) by mass,

[0068] Fe2O3: 0 to 20% (for example 5 to 12%) by mass,

[0069] Na2O+K2O: 0 to 10% (for example 2 to 9%) by mass,

[0070] B2O3: 0 to 1% by mass.

[0071] By contrast, the term glass wool generally refers to mineral wools with fibers whose chemical composition includes the following constituents:

[0072] i) for glass wools known as low alumina:

[0073] SiO2: 50 to 75% by mass,

[0074] Al2O3: 0 to 8% by mass,

[0075] CaO+MgO: 5 to 20% by mass,

[0076] Fe2O3: 0 to 3% by mass,

[0077] Na2O+K2O: 6 to 20% by mass,

[0078] B2O3: 0 to 14% by mass;

[0079] ii) for glass wools known as high alumina:

[0080] SiO2: 35 to 55% by mass,

[0081] Al2O3: 16 to 27% by mass,

[0082] CaO+MgO: 3 to 30% by mass, preferably 3 to 19% by mass,

[0083] Fe2O3: 0 to 15% by mass,

[0084] Na2O+K2O: 5 to 17% by mass, preferably 11 to 17% by mass,

[0085] B2O3: 0 to 5% by mass.

[0086] In this application, compositions are expressed in oxide form by convention. In particular, if the (total) iron oxide content is expressed as Fe₂O₃, this does not mean that this iron oxide is necessarily and exclusively present in its ferric form. Iron oxide can be present in both its ferric (Fe₂O₃) and ferrous (FeO) forms, and it is purely by convention that Fe₂O₃ designates the total iron oxide content.

[0087] Preferably, the sum of the mass concentrations of SiO2, Al2O3, CaO, MgO, Fe2O3, Na2O, and K2O in the raw material composition according to the invention, in the cullet compositions (i.e., glass fraction of cullet), and in the wool compositions described in this application is greater than or equal to 90%, or even greater than or equal to 95%.

[0088] It is understood that the compositions of cullet and mineral wools described in this application may include other oxides, generally present in trace amounts, such as MnO, P2O5 or TiO2.

[0089] The external centrifugal fiber-forming process is well known to those skilled in the art. In this process, the material to be fiberized is poured in a molten state onto the peripheral belt of rotating centrifugal wheels, is accelerated by these wheels, detaches from them, and is partially transformed into fibers under the effect of centrifugal force. A gas stream is emitted tangentially to the peripheral belt of the wheels so as to pick up the fiber-formed material, separating it from the non-fibrous material and conveying it to a receiving organ. For example, reference may be made to patent application EP195725 for external centrifugal fiber-forming.

[0090] The external centrifugal fiber-making process is commonly used to produce rock wool.

[0091] The external centrifugal fiber-pulling process is distinct from the internal centrifugal fiber-pulling process. The latter involves introducing a stream of molten, stretchable material into a centrifuge, also called a fiber-pulling plate, rotating at high speed. Such a fiber-pulling plate may or may not have a base and is perforated around its periphery by a very large number of orifices through which the material is projected in the form of filaments under the effect of centrifugal force. By means of an annular burner, these filaments are then subjected to the action of an annular gaseous drawing current at high temperature and speed (up to 1000°C or even 1200°C for the temperature, and 250 m / s for the speed, depending on the desired product) along the wall of the centrifuge, which thins them and transforms them into fibers. Such a process is described in patent applications EP 0189354 or EP 0519797.

[0092] The external centrifugal fiber-making process is commonly used to produce low or high alumina glass wool.

[0093] Preferably, the raw material composition according to the invention is adapted to be melted and fibered by external centrifugation to obtain rock wool.

[0094] The raw material composition according to the invention comprises from 1% to 99% by mass of a cullet including a glass fraction and from 0.001% to 20% by mass of metallic residues. This "cullet including a glass fraction and from 0.001% to 20% by mass of metallic residues" is also referred to in this application as "cullet with metallic residues," for the sake of simplicity and clarity.

[0095] Typically, the raw material composition according to the invention comprises from 2 to 70%, preferably from 2% to 50%, or even from 4 to 20%, or from 5 to 15%, by mass of said cullet with metallic residues.

[0096] Said cullet with metallic residues typically comprises a glass fraction and metallic residues distinct from this glass fraction.

[0097] Said cullet with metallic residues may for example be cullet from photovoltaic panels or cells, cullet from reinforced glass, cullet from automotive glass (e.g. windshield with heated metal wires), cullet from decorated glass, cullet from mirror glass, cullet from mineral wool with metallic reinforcement or surfacing (e.g. aluminum surfacing), or a mixture of these.

[0098] The cullet with metallic residues generally has a d50 of 1 to 150 mm, for example, 1 to 40 mm, 5 to 15 mm, 40 to 150 mm, or 80 to 120 mm. In some embodiments, the d50 of the cullet with metallic residues is 40 to 150 mm, preferably 80 to 120 mm. In other embodiments, the d50 of the cullet with metallic residues is 1 to 40 mm, preferably 5 to 15 mm.

[0099] The d50 indicates the value for which 50% of the particles—by number—have a size less than or equal to this value, and 50% of the particles—by number—have a size greater than this value. The d50 can be determined by laser granulometry. The “size” of a particle refers to the particle's Feret diameter, which is defined as the maximum distance between two parallel lines between which the particle can geometrically be inscribed.

[0100] The glass fraction of said cullet with metallic residues can be, for example, silico-sodo-calcic glass.

[0101] Typically, the chemical composition of the glass fraction of said metallic residue cullet comprises, in mass percentage:

[0102] - SiO2: from 50 to 80%,

[0103] - Na2O: from 3 to 20%,

[0104] - CaO: from 3 to 20%,

[0105] - MgO: from 0 to 10%,

[0106] - A12O3: from 0 to 5%,

[0107] - K2O: from 0 to 10%, and

[0108] - Fe2O3: from 0 to 15%.

[0109] More specifically, the chemical composition of the glass fraction of said cullet with metallic residues may comprise, as a mass percentage:

[0110] - SiO2: from 50 to 80%, [YES] - Na2O: from 5 to 20%,

[0112] - CaO: from 5 to 20%,

[0113] - MgO: from 1 to 10%,

[0114] - A12O3: from 0 to 5%,

[0115] - K2O: from 0 to 10%, and

[0116] - Fe2O3: from 0 to 15%.

[0117] More specifically, the chemical composition of the glass fraction of said cullet with metallic residues may comprise, as a mass percentage:

[0118] - SiO2: 69 to 80%, preferably 70 to 75%,

[0119] - Na2O: from 8 to 20%, preferably from 10 to 20%,

[0120] - CaO: from 5 to 20%, preferably from 5 to 15%,

[0121] - MgO: from 1 to 10%, preferably from 2 to 7%,

[0122] - A12O3: from 0 to 5%, preferably from 0.5 to 3%,

[0123] - K2O: from 0 to 10%, preferably from 0 to 2%, and

[0124] - Fe2O3: from 0 to 15%, preferably from 0 to 10%.

[0125] In some embodiments, the cullet with metallic residues is a low alumina glass wool cullet comprising metallic residues, and the glass fraction of said cullet with metallic residues has the chemical composition of a low alumina glass wool as defined above.

[0126] In some embodiments, the cullet with metallic residues is a high alumina glass wool cullet comprising metallic residues, and the glass fraction of said cullet with metallic residues has the chemical composition of a high alumina glass wool as defined above.

[0127] The glass fraction of said cullet with metallic residues generally represents from 80 to 99.999%, for example from 95 to 99.99%, from 90 to 99.99%, from 90 to 99.95%, from 90 to 99.9%, from 93 to 99.9%, from 95 to 99.9%, from 95 to 99.5%, or from 95 to 99%, of the mass of said cullet with metallic residues.

[0128] Said metallic residue cullet comprises 0.001 to 20% by mass of metallic residues.

[0129] Advantageously, said metallic residue cullet comprises from 0.01 to 10%, preferably from 0.05 to 10%, or even from 0.1% to 10%, or even from 0.1% to 7%, or even from 0.1 at 5% or even from 0.5 to 5%, for example from 1 to 5%, by mass of metallic residues (relative to the total mass of said cullet with metallic residues).

[0130] Metallic residues are typically solid elements in metallic and unoxidized form. Metallic residues may, in particular, be based on transition metals (e.g., iron, tantalum), post-transition metals (e.g., lead, cadmium, aluminum), lanthanides, actinides, or semi-metals (e.g., silicon). Examples include constituents of photovoltaic cells (e.g., silicon), constituents of the reinforcement of reinforced glass (e.g., iron), metallic pollutants (e.g., aluminum), elements from components used in thin-film technologies (e.g., copper, silver, tellurium, cadmium, indium, rare earth elements), elements from paints on decorated glass (e.g., lead, cadmium) or mirrors (e.g., silver, copper, aluminum, lead).

[0131] In some embodiments, the metallic residues comprise (for example, in a mass content of at least 70%, at least 80%, at least 90%, or even at least 95%, relative to the total weight of the metallic residues) one or more of the following elements selected from: Si, Al, Fe, Te, Cd, In, Pb, Ta, Cu, Ag, Sc, Y, and a lanthanide.

[0132] In a particular embodiment, the metallic residues are chosen from the following: Si, Al, Fe, Te, Cd, In, Pb, Ta, Cu, Ag, Sc, Y, a lanthanide, and a combination of at least two of these.

[0133] Said cullet with metallic residues may further comprise residues of organic matter. Thus, in certain embodiments, said cullet with metallic residues has a loss on ignition (LOI), after drying, of 0.001% to 20%, for example, 0.01% to 15%, 0.05% to 10%, or 0.1% to 5%.

[0134] The loss on ignition LOI of a cullet corresponds to the mass change, expressed as a percentage by mass of dry matter, resulting from heating the cullet to 550°C. The loss on ignition can be determined in accordance with ISO / TR 12389:2009. More specifically, the loss on ignition LOI can be defined as the ratio (IM2-M1I / Ml) x 100 (expressed as a percentage) where:

[0135] - Ml is the mass of the dry calcine (typically obtained after drying the calcine at 105°C) for at least 3 hours), and

[0136] - M2 is the mass of the calcine after heating the dry calcine to 550°C for at least 3 hours.

[0137] When the calcine is not in the form of a powder, a grinding step is advantageously implemented after the drying step (e.g. drying at 105°C) and before the heating step at 550°C.

[0138] Advantageously, said metal-residue cullet is in the form of a formed composite (for example, a briquette). The formed composite is typically formed from a mixture comprising:

[0139] - from 1 to 99%, preferably from 1 to 25%, or even from 5 to 20%, by mass of said calcined metallic residues,

[0140] - from 1 to 40%, preferably from 2 to 20%, or even from 10 to 20%, by mass of a binder, and

[0141] - from 0 to 98%, preferably from 55 to 97%, or even from 60 to 85%, by mass of charges minerals,

[0142] in relation to the total dry weight of said mixture.

[0143] It is understood that, when the cullet is in the form of a formed composite, the contents expressed for or in relation to said metallic-residue cullet are determined on the basis of the mass of metallic-residue cullet as such and not in relation to the mass of the formed composite. For example, a raw material composition of 100 g comprising 50 g of a formed composite comprising 10 g of metallic-residue cullet has a metallic-residue cullet content of 10% by mass.

[0144] The binder of the formed composite serves to ensure its cohesion. Such binders are well known to those skilled in the art. It may be a hydraulic binder, such as a cement-based or clay-based binder. The cement generally comprises clinker, and preferably one or more constituents selected from blast furnace slag, steel slag, fly ash, pozzolan, silica fume, limestone, and calcined clay. The cement may, for example, be Portland cement, composite Portland cement, blast furnace slag cement, composite cement, pozzolanic slag cement, calcined limestone and clay cement, aluminous cement, sulfoaluminate cement, supersulfated cement, rapid-setting cement, Sorel cement, or a mixture thereof. The cement is advantageously a cement as defined by standard EN 197-1 or standard EN 197-5.

[0145] In some embodiments, the binder components have a d50 less than 200 pm, in particular less than 100 pm.

[0146] Alternatively, the binder may be based on a two-component resin (e.g., epoxy resin).

[0147] The mineral fillers of the formed composite can be selected from mineral materials inert to the binder, which may be aggregates useful for the mechanical stability of the formed composite or components useful for the vitrifiable filler. The mineral fillers (e.g., aggregates) generally have a d50 greater than 200 µm, in particular greater than 1 mm. In a particular mode, The mineral fillers are chosen from gravel, inert slag (or equivalently "non-reactive slag"), and a mixture of these.

[0148] More specifically, this may refer to aggregates from industrial recycling channels that recover industrial by-products (or co-products) or from the demolition of buildings or roads (concrete chips, bricks, recycled railway ballast, road surface crusts or millings, or mine spoil heaps). Inert slag, as a mineral filler, is coarse and does not particularly form silicate ions in the presence of water. Furthermore, it is crystalline to more than 20% of its weight and has a large particle size distribution with a median diameter d50 greater than 50 µm, for example, a d50 greater than 200 µm, notably greater than 1 mm. The same applies to gravel. This may include, in particular, low-density slag from converters, which is solidified without quenching after extraction, thereby crystallizing.This mineral filler is inert, insofar as it does not participate in the chemistry of the solidification of the formed composite.

[0149] The molded composite is formed by mixing the aforementioned ingredients (i.e., cullet with metallic residues, binder, mineral fillers). The mixture for preparing the molding compound can be made in any suitable mixer. It is generally unnecessary to heat the mixture by adding heat from an external source. The temperature of the mixture may rise due to the solubilization of certain ingredients. When the binder is a hydraulic binder, water is introduced in sufficient quantity to ensure that the hydraulic binder is distributed throughout the molding compound, but not so much that the molded composite retains its shape upon demolding, if applicable after compaction. Generally, water is present in the mixture at a rate of 2 to 30% by weight (preferably 4 to 15% by weight), relative to the total dry weight of the mixture.The pH of the mixture is generally basic, typically at least equal to 8, or even at least equal to 10, or at least equal to 11.

[0150] The molding mass obtained from the mixture is then transformed into a formed composite, in particular into briquettes, by molding and optionally compaction. In particular, the molding mass can be placed in a mold, vibrated to remove trapped air, and then optionally compacted by applying pressure to one of the moving faces of the mold.

[0151] The formed composite then hardens naturally. It can dry out over time, so its water content can be significantly reduced with storage time. Its water content can vary depending on its storage conditions.

[0152] The formed composite generally has a volume greater than 1 cm3, or even greater than 20 cm3, in particular between 100 and 1000 cm3.

[0153] When the metal residue cullet is used in the form of a formed composite, the content of said formed composite in the raw material composition is typically 5 to 100% by mass, preferably 15 to 70%, or even 20 to 60% by mass, or 30 to 50% by mass (relative to the total weight of the raw material composition).

[0154] When the metal residue cullet is used in the form of a formed composite, the metal residue cullet advantageously has a d50 of 1 to 40 mm, preferably of 5 to 15 mm.

[0155] When the metal residue cullet is used as such (i.e. not put into the form of a formed composite), the metal residue cullet advantageously has a d50 of 40 to 150 mm, preferably of 80 to 120 mm.

[0156] The composition of raw materials may include both:

[0157] - of metallic residue cullet in the form of a conformed composite (“Cl”), such as defined above, and

[0158] - of the cullet with metallic residues used as such (i.e. which is not put into the form of conformed composite) ("C2"), as defined above.

[0159] In this case, the content of calcine Cl in the raw material composition is typically from 5 to 70%, or even from 20 to 60% by mass, or even from 30 to 50% by mass (relative to the total weight of the raw material composition); and the content of calcine C2 is typically from 1 to 50%, or even from 3 to 30% by mass, or even from 5 to 10% by mass (relative to the total weight of the raw material composition).

[0160] The calcin Cia advantageously has a d50 of 1 to 40 mm, preferably from 5 to 15 mm. The calcin C2 advantageously has a d50 of 40 to 150 mm, preferably from 80 to 120 mm.

[0161] The composition of raw materials generally also includes other raw materials, such as:

[0162] - oxides or salts (e.g. sodium carbonate, potash, or borax),

[0163] - natural raw materials (e.g. silicic sands, dolomite, limestone, slag, bauxite, feldspar, anorthosite, felith), which are generally combinations of oxides,

[0164] - mineral wool waste, in particular glass wool and / or rock wool, which may originate from the production of said fibres or from construction or deconstruction sites, and may be associated with paper, aluminium or bituminous films, or wooden pallet elements,

[0165] - waste mineral fibers (of the type used in reinforcement),

[0166] - liquid or solid fuels (e.g., plastic, composite material or not, organic matter, coal),

[0167] - flat glass cullet or household cullet (i.e. without metallic residues),

[0168] - recyclable materials from laminated glazing with polymer sheets of the polyvinyl butyral type such as windshields, and / or

[0169] - industrial co-products (e.g. blast furnace slag, converter slag, ...).

[0170] When the metal residue cullet is in the form of a formed composite, one or more of the raw materials (in particular chosen from those mentioned above) used to form the raw material composition according to the invention may also be included in the formed composite.

[0171] A general method that can be implemented by a furnace operator to develop a composition of raw materials according to the invention is detailed below.

[0172] In a first step, a target composition that meets the viscosity criteria for melting and fiberizing by external centrifugation (mentioned above) is selected. To aid in the selection of this target composition, a furnace operator uses models relating the chemical composition and dynamic viscosity of a mixture, such as those commonly used in the glass industry. In an industrial context and in a known manner, other considerations can also be taken into account in the selection of the target composition, such as the final cost of the composition, the energy required for its melting, and compliance with certain concentration ranges for the chemical compounds.

[0173] In a second step, the operator prepares his mixture taking into account the respective chemical composition of each of the raw materials at his disposal, and adjusts the relative proportions of each of these raw materials to obtain the target composition.

[0174] According to an alternative embodiment, an operator can start by taking into account the respective composition of each of the raw materials at his disposal in order to subsequently adjust the relative proportions of the latter and, empirically, determine and obtain a target composition which, on the basis of the models at his disposal, meets the viscosity criteria to be fibered by external centrifugation.

[0175] Another object of the present invention is a method for producing a glass comprising the following steps:

[0176] a) feeding a melting chamber with a composition of raw materials as defined in this application, as a vitrifiable filler, and

[0177] b) melting said formed composite in said melting chamber, to obtain a bath of molten material.

[0178] The melting chamber is advantageously a furnace (typically vertical), configured to stratify the molten raw materials according to their density, and advantageously configured to draw off the densest molten raw materials from its lower part.

[0179] Generally, molten raw materials are divided into several cuts, including in particular:

[0180] - an intermediate section comprising the molten glass,

[0181] - a cut comprising high-density raw materials, i.e. having a density higher than that of the intermediate section, typically at least 4% higher, or even at least 10% higher, compared to the density of the intermediate section,

[0182] - a cut comprising low-density raw materials, i.e. having a density lower than that of the intermediate section, typically lower by at least 4%, or even lower by at least 10%, compared to the density of the intermediate section.

[0183] Melting typically takes place under reducing conditions. These reducing conditions are typically made possible by the presence of coke (which is not a raw material within the meaning of the invention), which is added to the melting chamber and is thus in contact with the molten raw materials. Preferably, the melting chamber is a cupola furnace.

[0184] During the process of the invention, the densest molten raw materials are removed by drawing off the lower part of the melting chamber. Low-density molten raw materials may be on the surface of the molten pool and may be removed by skimming.

[0185] Upon exiting the melting chamber, the molten composition can either be immediately fibered by external centrifugation, or be cooled and transformed into cullet, to be later (subsequently) remelted and fibered by external centrifugation to obtain mineral wool.

[0186] Another object of the present invention is a method for manufacturing mineral wool, comprising:

[0187] - steps a) and b) of the production process as described above,

[0188] - a step c) of fiberizing said molten material bath, preferably by external centrifugation.

[0189] Another object of the present invention is a glass obtained by the production process as defined in this application.

[0190] Another object of the present invention is a mineral wool obtained by the manufacturing process as defined in this application.

[0191] It is understood that the various aspects, particular and preferred embodiments described above for the composition of raw materials also apply to processes for the production of glass or the manufacture of mineral wool which use such a composition of raw materials.

[0192] Other features and advantages of the invention will become apparent from the following examples, which are given purely for illustrative purposes and are not intended to limit the scope of the invention as defined by the attached claims. EXAMPLES

[0193] The target rock wool composition described in Table 1 below was selected by a furnace operator.

[0194] [Tables 1] Constituent % mass SiO2 42.05 Al2O3 16.57 CaO 25.45 MgO 6.28 Fe2O3 4.74 Na2O 1.26 K2O 1.34 B2O3 -

[0195] Characteristics of the target rock wool:

[0196] Visco Tlog 1 = 1464°C

[0197] Visco Tlog 3=1110°C

[0198] Tlogl - Tlog3 = 354°C

[0199] To obtain this target composition, the operator uses as raw materials, in particular, dolomite, basalt, bauxite, feldspar, and cullet with metallic residues. The compositions of three cullets with metallic residues are detailed in Table 2 below. Cullet 1 is reinforced glass cullet, cullet 2 is crushed high-alumina mineral wool cullet containing metallic residues, and cullet 3 is crushed low-alumina mineral wool cullet containing metallic residues (metallic binders, particularly iron-based, for cullet 1 and aluminum surfacing for cullets 2 and 3). Coke was used as fuel and reducing agent.

[0200] [Tables2] Cullet 1 (%m.) Cullet 2 (%m.) Cullet 3 (%m.) Glass fraction: 99.9 99.9 99.9 Chemical composition (% w) - SiO2 71.3 41 65.3 - Al2O3 1.3 23 2.1 - CaO 9.7 14 8.1 - MgO 3.9 2 2.4 - Fe2O3 0.02 5.5 0.1 - Na2O 13.8 6 16.4 - K2O - 6 0.7 - B2O3 - - 4.5 Metallic residues: 0.1 0.1 0.1

[0201] The calcins 2 and 3 were used in the form of a formed composite. The details of the chemical composition, in mass percentages (%w), of these formed composites are given in Table 3 below.

[0202] [Tables3] Composite A Composite B - Basalt 22 22 - Dolomite 26 26 - High alumina glass wool waste 28 22 - Cement 12 12 - Calcin 2 12 - - Calcin 3 - 18

[0203] The mass proportions (%m) of each of the raw materials were adjusted, as shown in Table 4 below, to obtain the target composition. The C1-C3 raw material compositions were melted in a cupola furnace, and the metallic elements were removed by draining.

[0204] [Tables4] Cl C2 C3 Calcin 1 6 - - Conformed Composite A - 30 (3.6%)* - Conformed Composite B - - 30 (5.4%)* Basalt 48 60 53 Bauxite 9 - 5 Dolomite 30 10 12 Feldspar 7 - - Visco T log 1 1454 1467 1459 Visco T log 3 1100 1110 1100 Tlogl - Tlog3 354 358 359

[0205] * calcine content in the total mixture of raw materials

[0206] Starting from each of the calcine compositions 1, 2, and 3, by adding materials By adapting the initial parameters, the target composition of rock wool was obtained. It was possible to introduce mass concentrations of 3 to 12% of metal-residue cullet into the vitrifiable mixture, while still meeting the criteria necessary for melting and fiberization by external centrifugation.

Claims

Demands

1. Composition of raw materials suitable for melting and fibering by external centrifugation to obtain mineral wool, characterized in that it comprises from 1 to 99% by mass of a cullet comprising: - a glass fraction and - 0.001 to 20% by mass of metallic residues.

2. Composition of raw materials according to claim 1, characterized in that it comprises from 2 to 70%, preferably from 2 to 50%, or even from 4 to 20%, or even from 5 to 15%, by mass of said calcin.

3. Composition of raw materials according to claim 1 or 2, characterized in that the glass fraction of said cullet has a chemical composition comprising, in mass percentage: - SiO2: from 50 to 80%, - Na2O: from 3 to 20%, - CaO: from 3 to 20%, - MgO: from 0 to 10%, - Al2O3: from 0 to 5%, - K2O: from 0 to 10%, and - Fe2O3: from 0 to 15%.

4. Composition of raw materials according to any one of claims 1 to 3, characterized in that said cullet comprises from 0.01 to 15%, from 0.1 to 10%, or even 1 to 4%, by mass, of metallic residues.

5. Composition of raw materials according to any one of claims 1 to 4, characterized in that the metallic residues comprise one or more elements selected from: Si, Al, Fe, Te, Cd, In, Cu, Pb, Ta, Ag, Sc, Y, and a lanthanide.

6. Composition of raw materials according to any one of claims 1 to 5, characterized in that said calcin has a loss on ignition, after drying, of 0.001 to 20%.

7. Composition of raw materials according to any one of claims 1 to 6, characterized in that said mineral wool has a chemical composition comprising, in mass percentages: SiO2: 30 to 75%, A12O3: 0 to 30%, CaO+MgO: 5 to 45%, Na2O+K2O: 0 to 20%, Fe2O3: 0 to 20%, B2O3: 0 to 14%.

8. Composition of raw materials according to any one of claims 1 to 7, characterized in that said mineral wool has a chemical composition comprising, in mass percentages: SiO2: 30 to 50%, Al2O3: 10 to 24%, CaO+MgO: 20 to 45%, Fe2O3: 0 to 20%, Na2O+K2O: 0 to 10%, and B2O3:0 to 1%.

9. Raw material composition according to any one of claims 1 to 8, characterized in that said cullet is in the form of a formed composite made from a mixture comprising: - from 1 to 99%, preferably from 1 to 25%, or even from 5 to 20%, by mass of said cullet comprising from 0.001 to 20% by mass of metallic residues, - from 1 to 40%, preferably from 2 to 20%, or even from 10 to 20%, by mass of a binder, and - from 0 to 98%, preferably from 55 to 97%, or even from 60 to 85%, by mass of mineral fillers, relative to the total dry weight of said mixture.

10. A method for producing a glass comprising the following steps: a) feeding a melting chamber with a composition of raw materials as defined in any one of claims 1 to 9, as a vitrifiable filler, and b) melting said composition of raw materials in said melting chamber, to obtain a bath of molten material.

11. 11. A method for manufacturing mineral wool, comprising the following steps: a) feeding a melting chamber with a composition of raw materials as defined in any one of claims 1 to 9, as a vitrifiable filler,

12.

13.

14.

15. b) the melting of said composition of raw materials in said melting chamber, to obtain a bath of molten material, and c) the fiberization of said bath of molten material. A method for producing a glass according to claim 10, wherein the melting chamber is a vertical furnace configured to stratify the molten raw materials, according to their density, preferably the melting chamber is a cupola furnace. A method for manufacturing mineral wool according to claim 11, wherein the melting chamber is a vertical furnace configured to stratify the molten raw materials, according to their density, preferably the melting chamber is a cupola furnace. Glass obtained by the production process as defined in claim 10 or 12. Mineral wool obtained by the manufacturing process as defined in claim 11 or 13.