COMPOSITION AND PRODUCTION PROCESS OF GLASS

Abstract

The present invention relates to a raw material composition comprising recycled materials containing organic matter, suitable for the production of boron-containing glass. It further relates to a glass production process, as well as glass obtained by such a process. It also relates to a process for manufacturing mineral wool, as well as mineral wool obtained by such a process.

Description

Title of the invention: COMPOSITION AND METHOD FOR PRODUCING GLASS

[0001] The present invention relates to a raw material composition, comprising recycling materials comprising organic matter, suitable for the production of a glass comprising boron. It further relates to a method for producing glass, as well as a glass obtained by such a method. It also relates to a method for manufacturing a mineral wool, as well as a mineral wool obtained by such a method.

[0002] The production of a glass typically comprises a step of melting a composition of raw materials (or “mixture of vitrifiable materials”) followed, where appropriate, by various steps aimed at refining and conditioning the bath of molten material with a view to the final shaping of the glass, in particular in the form of hollow glass (flasks, bottles), continuous glass fibers, known as textile threads, used in particular in reinforcement, or in the form of mineral wool (in particular rock wool or glass wool) used for thermal and / or acoustic insulation applications.

[0003] It is known to recycle glass waste, in particular in the form of cullet, by reintroducing this waste into glass production processes. The presence of organic matter in these recycling materials such as cullet, in particular household cullet (bottle glass in particular) or cullet from laminated glass waste, can however affect the melting performance of the raw material composition. A phenomenon known as "foaming" can in fact be observed when the raw material composition comprises a significant quantity of organic matter. This phenomenon, particularly observed in the case of at least partly electric melting, causes the formation of a layer of foam on the surface of the molten bath. The layer of foam acts as a heat shield.Heat transfers are thus limited, which has the effect of disrupting the melting of the raw material composition newly introduced into the furnace and / or the control of temperatures within the molten material bath.

[0004] To avoid these drawbacks, one solution is to reduce or eliminate organic matter from the recycling materials, for example by combustion or by separation / washing methods, before their introduction into the melting furnaces. For example, the organic matter content of recycling materials, such as cullet, can be reduced by eliminating at least some of the fine particles, typically those smaller than 10 mm, before introduction into the melting furnace. These strategies allow for the production of recycled materials considered to be of good quality for the glass industry, i.e. containing little organic matter. However, they require additional facilities, significantly reducing the economic and environmental attractiveness of these recycled materials. Another strategy consists of adding solid oxidants to the glass-making mixture, with the aim of oxidizing organic matter before it causes foaming. However, in addition to being an expensive strategy, the oxidants used cause NOx and SOx gas emissions, enrich the glass with minor elements, sometimes colorings, and can reduce biosolubility.

[0005] There is therefore a need to be able to use more recycled materials including organic materials in glass production processes without disrupting the operation of melting furnaces.

[0006] In this context, the present invention aims to provide a raw material composition that can be used in a glass production process that maximizes recycling capacity while avoiding all or part of the drawbacks set out above. Thus, the present invention relates to a raw material composition suitable for producing a glass having a boron CB content, expressed as B2O3, of 0.5 to 14% by weight (for example, 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, 8 to 12%, 1 to 7%, 4 to 7%, 0.5 to 7%,

[0007] from 1.5 to 6%, or from 1.5 to 3.5% by weight), characterized in that said composition comprises recycling materials comprising organic matter and has a loss on ignition LOI such that: [Eql] (i+o,37Cb) In this application, LOI and CB are expressed as mass percentages in the equations involving them.

[0008] The Applicant has in fact demonstrated that the presence of boron in the composition of raw materials accentuates the foaming phenomenon. Without wishing to be bound by any theory, it is assumed that the presence of boron tends to stabilize the foam and / or slow down the elimination of the foam generated by the presence of organic compounds in the composition of raw materials. The presence of boron thus promotes the accumulation of foam and increases the disturbances linked to this phenomenon. The invention takes this discovery into account to maximize the quantity of recycling material, in particular lower quality recycling material, i.e. comprising a significant quantity of organic matter, which can be introduced into the furnace while reducing, or even avoiding, the foaming phenomenon.

[0009] The loss on ignition of a composition of raw materials, noted LOI, and the loss on fire of a raw material i (for example, a recycling material i), noted LOI;, are representative of the quantity of organic matter contained respectively in the composition of raw materials and in the raw material i.

[0010] The LOI; of a raw material i corresponds to the mass variation, expressed as a percentage of dry matter mass, resulting from heating the raw material up to 550°C.

[0011] The loss on ignition LOI; of a raw material i can be determined in accordance with ISO / TR 12389:2009.

[0012] More particularly, the loss on ignition LOI; of a raw material i can be defined as the ratio (IM^-Mljl / Ml; ) x 100 (expressed in %) where:

[0013] - Ml; is the mass of the dry raw material i (typically obtained after drying said raw material i at 105°C for at least 3 hours), and

[0014] - M2i is the mass of the raw material i obtained after heating said material first i dry at 550°C for at least 3 hours.

[0015] When the raw material is not in the form of a powder, a grinding step is advantageously carried out after the drying step (e.g. drying at 105°C) and before the heating step at 550°C.

[0016] The loss on ignition LOI of a raw material composition is the weighted average of the losses on ignition LOI; of the raw materials i of the composition, said LOI of the composition being expressed relative to the final glass weight (i.e. glass obtained from said raw material composition). More particularly, the loss on ignition LOI of a raw material composition can be defined by the following equation (Eq 2):

[0017] LAW(%) = x = ^EjMlr M2\

[0018] where:

[0019] - LOI; is the loss on ignition of raw material i (obtained as indicated above) above), expressed in %,

[0020] - Ml; is the mass of the dry raw material i (typically obtained after drying of said raw material i at 105°C for at least 3 hours), and

[0021] - M2i is the mass of the raw material i obtained after heating said material first i dry at 550°C for at least 3 hours,

[0022] - Mverre is the final glass mass.

[0023] For example, the LOI of a 110 kg composition comprising 30 kg (by dry weight) of a recycling material i having a LOI of 0.25% and 35 kg (by dry weight) of a recycling material j having a LOIj of 0.20% (the other raw materials of the composition having a zero LOI), and making it possible to obtain 100 kg of final glass, is: [(30 / 100)*0.25 + (35 / 100)*0.20].

[0024] The raw material composition typically comprises at least 10%, for example at least 20%, preferably at least 30%, more preferably at least 35%, or even at least 40%, and typically up to 70%, preferably up to 80%, or even up to 90%, by weight of recycling materials. In some embodiments, the raw material composition comprises 10 to 90%, preferably 15 to 80%, more preferably 20 to 50%, by weight of recycling materials. The recycling materials may comprise from 0.01 to 30% (for example from 0.02 to 25%, from 0.05 to 15% or from 10 to 30%), more preferably from 0.05 to 2% by weight of organic materials.

[0025] The recycling materials can be of different natures such as mineral fiber waste, in particular mineral wool, flat glass, bottles, also called household cullet, or composite materials combining glass and plastic materials. Flat glass waste, generally in the form of cullet, can come from building or automobile glazing, in particular glazing laminated with a polymer sheet. The mineral fibers can be textile or reinforcing fibers, possibly sized, or mineral wools, such as glass wools or rock wools typically used in thermal or acoustic insulation. Mineral wool waste can come from production sites (factories) of said wools, from construction sites (construction, deconstruction, or demolition) and / or from recycling channels making it possible to recover said wools in final products, whether or not they are used.They may include, typically up to 10%, an organic binder. The recycling materials may be a cullet obtained by melting waste fibers or mineral wools. The recycling materials may be a cullet obtained by melting waste in a submerged burner furnace.

[0026] In some embodiments, the recycling materials are selected from cullet, such as household cullet or laminated glass cullet, waste fibers or mineral wools, and a combination of at least two of these materials.

[0027] Preferably, the recycling materials are chosen from cullets, in particular household cullet and laminated glass cullet.

[0028] The raw material composition may contain one or more sources of recycling materials. In some embodiments, the raw material composition comprises several sources of recycling materials. It is thus possible to adjust the organic matter content provided by the recycling materials in the raw material composition, for example by combining lower quality recycling materials (in particular recycling materials having a high LOI) with higher quality recycling materials (in particular recycling materials having a low LOI), to satisfy the LOI as defined in the present invention. This is particularly advantageous in that it allows

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[0030]

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[0032]

[0033]

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[0035]

[0036]

[0037] recover lower quality recycling materials, the use of which generally remains limited due to the risks associated with the foaming phenomenon, without however reducing the total proportion of recycling materials introduced into the composition of raw materials. As such, the recycling materials introduced into the composition of raw materials comprise, in certain embodiments, at least 30%, preferably at least 50%, by weight of a recycling material having an LOI; of at least 0.05%, preferably at least 0.1%, or even at least 0.5%. Generally, the composition of raw materials is preferably such that: [Eq 3] LQI >___2121___, (1+0,37CS) better still, such as: [Eq4] T / AT 0.09 LAW > 77---7 ' (1+0.37Cb) where, in equations 3 and 4, LOI and CB are as defined above. Conventional raw materials, particularly from natural resources, may be present in the composition of raw materials, particularly to adjust the composition of the glass produced. These conventional raw materials may in particular be in the form of pure oxides, salts (such as sodium carbonate, potash, or borax), natural raw materials (silica sands, dolomite, limestone, waste rock, slag, bauxite, feldspar, anorthosite, felith, etc.) which are already combinations of oxides. The chemical composition, expressed as oxides, of the glass produced is not particularly limited. However, it includes a boron CB content, expressed as B2O3 of at least 0.5%, preferably at least 1%, more preferably at least 1.5%, and up to 14%, preferably up to 7%, more preferably up to 6% by weight, or even up to 3.5%. In some embodiments, the produced glass may have a composition, expressed as oxides, comprising the following constituents, in weight percentages: SiO2 30 to 80%, A12O3 0 to 30%, preferably 0 to 10%, CaO+MgO 2 to 45%, Na2O+K2O 0 to 30%, Fe2O3 0 to 20%, and B2O3 0.5 to 14% (e.g., 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, 8 to 12%, 1 to 7% by weight, 4 to 7%, 0.5 to 7%, 1.5 to 6%, or 1.5 to 3.5%).

[0038] In some embodiments, the produced glass has a composition, expressed as oxides, comprising the following constituents, in weight percentages:

[0039] - SiO2: 50 to 75%, preferably 60 to 70%,

[0040] - Na2O: 10 to 25%, preferably 10 to 20%,

[0041] - CaO: 5 to 15%, preferably 5 to 10%,

[0042] - MgO: 1 to 10%, preferably 2 to 5%,

[0043] - CaO and MgO together preferably representing 5 to 20%,

[0044] - B2O3: 0.5 to 14% (for example, 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, from 8 to 12%, from 1 to 7% by weight, from 4 to 7%, from 0.5 to 7%, from 1.5 to 6%, or from 1.5 to 3.5%),

[0045] - A12O3: 0 to 8%, preferably 1 to 6%,

[0046] - K2O: 0 to 5%, preferably 0.5 to 2%,

[0047] - Na2O and K2O together preferably representing 6 to 20% (or even 12 to 20%),

[0048] - Fe2O3: 0 to 3%, preferably less than 2%, more preferably less than 1%.

[0049] In some embodiments, the produced glass has a composition, expressed as oxides, comprising the following constituents, in weight percentages:

[0050] - SiO2: 65 to 80%, preferably 70 to 75%,

[0051] - Na2O: 5 to 20%, preferably 8 to 15%,

[0052] - CaO: 5 to 20%, preferably 8 to 15%,

[0053] - A12O3: 0 to 10%, preferably less than 5%,

[0054] - MgO: 0 to 5%, preferably less than 3%,

[0055] - B2O3: 0.5 to 14% (for example, 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, from 8 to 12%, from 1 to 7% by weight, from 4 to 7%, from 0.5 to 7%, from 1.5 to 6%, or from 1.5 to 3.5%), and

[0056] - Fe2O3: 0 to 2%, preferably less than 1%.

[0057] In some embodiments, the produced glass has a composition, expressed as oxides, comprising the following constituents in weight percentages:

[0058] - SiO2: 69 to 80%, preferably 70 to 75%,

[0059] - Na2O: 8 to 20%, preferably 10 to 20%,

[0060] - CaO: 5 to 20%, preferably 5 to 15%,

[0061] - MgO: 1 to 10%, preferably 2 to 7%,

[0062] - A12O3: 0 to 5%, preferably 0.5 to 3%,

[0063] - K2O: 0 to 10%, preferably 0 to 2%,

[0064] - Fe2O3: 0 to 15%, preferably 0 to 10%,

[0065] - B2O3: 0.5 to 14% (for example, 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, from 8 to 12%, from 1 to 7% by weight, from 4 to 7%, from 0.5 to 7%, from 1.5 to 6%, or from 1.5 to 3.5%).

[0066] In some embodiments, the glass produced may have a composition, expressed as oxides, comprising the following constituents, in weight percentages:

[0067] a) - SiO2: 50 to 75%,

[0068] - A12O3: 0 to 8%,

[0069] - CaO+MgO: 5 to 20%,

[0070] - Fe2O3: 0 to 3%,

[0071] - Na2O+K2O: 6 to 20%,

[0072] - B2O3: 0.5 to 14% (for example, 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, from 8 to 12%, from 1 to 7% by weight, from 4 to 7%, from 0.5 to 7%, from 1.5 to 6%, or from 1.5 to 3.5%); or,

[0073] b) - SiO2: 35 to 55%,

[0074] - A12O3: 16 to 27%,

[0075] - CaO+MgO: 3 to 30%,

[0076] - Fe2O3: 0 to 15%,

[0077] - Na2O+K2O: 5 to 17%,

[0078] - B2O3: 0.5 to 14% (for example, 0.5 to 8%, 0.5 to 6% or 0.5 to 4%).

[0079] In some embodiments, the produced glass may have a composition, expressed as oxides, comprising the following constituents, in weight percentages:

[0080] SiO2: 30 to 50%,

[0081] A12O3: 10 to 22%,

[0082] CaO+MgO: 20 to 45%,

[0083] Fe2O3: 0 to 20%,

[0084] Na2O+K2O: 0 to 10%,

[0085] B2O3: 0.5 to 14% (for example, 0.5 to 8%, 0.5 to 6% or 0.5 to 4%).

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

[0087] In the different compositions described above for the glass produced, the sum of the SiO2 and Al2O3 contents is typically 50 to 80% by weight.

[0088] In the various compositions described above for the glass produced, the total content of SiO2, Al2O3, CaO, MgO, Na2O, K2O, Fe2O3, and B2O3 is typically su- greater than 80%, or even greater than 90%, or even greater than 95% by weight.

[0089] The chemical composition of the raw material composition, expressed as oxides based on the mineral portion of the raw material composition, is substantially identical to that of the produced glass.

[0090] Oxidizing agents are sometimes used in mixtures of vitrifiable materials to oxidize organic materials. Preferably, the raw material composition according to the invention does not comprise more than 2%, preferably not more than 1%, or even not more than 0.5%, in particular not more than 0.1% by weight of oxidizing agents. Even better, the raw material composition does not comprise oxidizing agents. Examples of such oxidizing agents are in particular a sulfate (e.g. sodium sulfate), a nitrate (e.g. sodium nitrate), or manganese dioxide (i.e. MnO2).

[0091] Another object of the present invention is a method for producing glass having a CBen boron content, expressed as B2O3, of 0.5 to 14% by weight (e.g., 1 to 12%, 2 to 10%, 5 to 14%, 7 to 13%, 8 to 12%, 1 to 7%, 4 to 7%, 0.5 to 7%, 1.5 to 6%, or 1.5 to 3.5% by weight), comprising the following steps: - feeding a furnace with a composition of raw materials as defined in this application; and - melting said composition in the furnace to obtain a bath of molten material.

[0092] It is understood that the particular and preferred methods described above for the composition of raw materials (also including the methods on the glass produced) apply to the glass production process as well as to the glass produced by this process.

[0093] The raw material composition described above can be introduced and melted in any type of glass furnace, such as a flame furnace, an at least partly electric melting furnace, and / or a hybrid melting furnace. The raw material composition can be introduced into the furnace from above or submerged.

[0094] The flame furnace comprises one or more burners, each of which may be overhead (the flames are arranged above the molten material bath and heat it by radiation) or submerged (the flames are created directly within the molten material bath). The or each burner may be fueled by various fuels such as natural gas or fuel oil.

[0095] By "electric melting" is meant that the vitrifiable mixture is melted by the Joule effect, by means of electrodes immersed in the bath of molten material, to the exclusion of any use of other heating means, such as flames. The vitrifiable mixture is normally distributed homogeneously over the surface of the bath of molten material using a mechanical device, and thus constitutes a screen thermal limiting the temperature above the molten pool, so that the presence of a superstructure is not always necessary. The electrodes can be suspended so as to immerse themselves in the molten pool from above, installed in the bottom, or installed in the side walls of the tank. The first two options are generally preferred for large tanks in order to best distribute the heating of the molten pool. The electrodes are preferably made of molybdenum, or possibly even tin oxide. The passage of the molybdenum electrode through the bottom is preferably done via a water-cooled steel electrode holder.

[0096] The hybrid melting furnace uses at least one burner and electrodes.

[0097] In certain particular modes, the furnace is a melting furnace at least in part electric.

[0098] In certain particular modes, the furnace is a hybrid melting furnace.

[0099] Another object of the present invention is a glass obtained by the production method as described above.

[0100] At the outlet of the furnace, the mixture of molten material can be shaped, for example, it can be put in the form of hollow glass (e.g. flasks, bottles), continuous glass fibers (so-called textile threads, which are used in particular in reinforcement), in the form of mineral wool (which is used in particular for thermal and / or acoustic insulation applications) or even in the form of cullet.

[0101] In certain embodiments, the glass according to the invention is in the form of cullet, in particular hot cullet (typically a bath of molten glass) or cold cullet (i.e. in solid form, for example particles of ground or granulated glass in water). In certain embodiments, the glass produced is in the form of cullet having a d50 of between 1 and 50 mm, preferably between 1 and 25 mm, better still between 1 and 10 mm, or even between 1 and 5 mm.

[0102] 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 Féret diameter of the particle, which is defined as the maximum distance between two parallel lines between which the particle can geometrically fit.

[0103] The glass according to the invention, when in the form of cullet, may in particular be an intermediate cullet with a view to forming another glass, for example by mixing with other raw materials. The intermediate cullet may or may not be cooled, before the formation of said other glass.

[0104] In a preferred embodiment, the molten mixture is formed into a mineral wool.

[0105] Thus, another object of the present invention is a method of manufacturing a mineral wool, including:

[0106] - the feeding and melting steps of the glass production process as described above, allowing a bath of molten material to be obtained, and

[0107] - the fiberization of the molten material bath.

[0108] It is understood that the particular and preferred modes described above for the composition of raw materials and for the glass production process apply to the mineral wool manufacturing process as well as to the mineral wool obtained by this process. In particular, the mineral wool typically has a composition such as those described above for said produced glass.

[0109] In a particular embodiment, the mixture of molten material (or equivalently “molten mixture”, or even “bath of molten material”) is immediately fiberized, to obtain mineral wool.

[0110] In another particular embodiment, the molten material mixture is cooled and transformed into cullet, which is subsequently (subsequently) melted again to be fiberized to obtain mineral wool.

[0111] The step of fiberizing the melt mixture can be carried out by internal or external centrifugation, preferably by internal centrifugation.

[0112] External centrifugation refers in particular to centrifugation during which the material to be fiberized is poured in the molten state onto the peripheral band of rotating centrifugation wheels, is accelerated by these wheels, detaches from them, and is partly transformed into fibers under the effect of centrifugal force, a gas stream being emitted tangentially to the peripheral band of the wheels so as to take charge of the fiberized material by separating it from the non-fiberized material and conveying it to a receiving member. For example, for external centrifugation, reference may be made to patent applications EP195725, EP 0465310 or EP 0439385.

[0113] Internal centrifugation consists of introducing a stream of the stretchable material in the molten state into a centrifuge, also called a fiberizing plate, rotating at high speed. Such a fiberizing plate can alternatively be equipped with or without a bottom and is pierced at 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-shaped burner, these filaments are then subjected to the action of an annular gaseous drawing current at high temperature and speed (which can reach 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. This type of centrifugation is described in particular in patents EP 0189354 or EP 0519797.

[0114] Another object of the present invention is a mineral wool obtained by the manufacturing process as described above.

[0115] Other characteristics and advantages of the invention will appear in the light of the following examples, which are given purely for illustrative purposes and are not intended to limit the scope of the invention, defined by the appended claims.

[0116] Examples

[0117] The three target glass compositions described in Table 1 below are selected by a furnace operator.

[0118] [Tables 1] Target compositions 1 (%m.) 2 (%m.) 3 (%m.) SiO2 65.1 67.9 54 A12O3 2.15 6.75 14.2 CaO 7.5 6.0 24.1 MgO 2.7 0.1 0.4 Na2O 16.6 12.2 0.6 K2O 0.65 2.3 0.1 B2O3 (CB) 4.2 1.35 6.1

[0119] In order to obtain these target compositions, the operator has raw materials such as dolomite, sand, sodium carbonate, borax, raw limestone, feldspar, and recycling materials (e.g. recycled cullet).

[0120] To obtain the target composition 1, the mixture of raw materials according to the invention described in Table 2 is melted. A comparative mixture is also melted. Material mixture according to the invention (% by weight of raw materials) Comparative material mixture (% by weight of raw materials) Recycled raw material* 27.4 45.7 Sand 34.7 22.5 Sodium carbonate 16.5 12.8 Borax pentahydrate 7.8 7.8 Raw limestone 0.9 0 Feldspar 7.3 6.0 Dolomite 5.3 3.9 CB (in final glass) 4.2% 4.2% LOI (based on final glass weight) 0.076% 0.126% LOIjimite 0.086% 0.086%

[0122] * Cullet having an LOI of 0.25%

[0123] To obtain the target composition 2, the mixture of raw materials according to the invention described in Table 3 is melted. A comparative mixture is also melted. Material mixture according to the invention (% by mass of raw materials) Comparative material mixture (% by mass of raw materials) Recycled raw material* 28.5 48.8 Sand 20.9 8.6 Sodium carbonate 10.3 6.6 Borax pentahydrate 2.6 2.7 Raw limestone 4.5 0.9 Feldspar 33.2 32.3 CB (in final glass) 1.35% 1.35% LOI (based on final glass weight) 0.11% 0.18% LOIjimite 0.15% 0.15%

[0125] * Cullet having an LOI of 0.35%

[0126] To obtain the target composition 3, the mixture of raw materials according to the invention described in Table 4 is melted. A comparative mixture is also melted. Material mixture according to the invention (% by mass of raw materials) Comparative material mixture (% by mass of raw materials) Recycled raw material* 8.1 16.6 Silica 26.6 24.1 Sodium carbonate 0.8 0.8 Colemanite 11.2 10.1 Raw limestone 25.9 23.5 Feldspar 0.4 0.4 Kaolin 26.8 24.4 CB (in final glass) 6.1% 6.1% LOI (based on final glass weight) 0.05% 0.1% LOIjimite 0.068% 0.068%

[0128] * Cullet having an LOI of 0.5%

[0129] Good foaming control is observed during the melting of the raw material mixtures according to the invention, having an LOI lower than the limit LOI imposed by the relationship LOI < (0.22 / (1+0.37CB)).

[0130] On the contrary, the fusion of the comparative mixtures, which have an LOI that is too high with regard to the boron content, generates significant foaming.

Claims

Claims

1. Raw material composition, suitable for the production of a glass having a boron CB content, expressed as B2O3, of 0.5 to 14% by weight, characterized in that said composition comprises recycling materials comprising organic matter and has a loss on ignition LOI such that: [Eq5] LOI<................ • ( i+0.37CB)

2. Composition according to claim 1, characterized in that it comprises 10 to 90%, preferably 15 to 80%, more preferably 20 to 50%, by weight of recycled materials.

3. Composition according to claim 1 or 2, characterized in that the recycling materials are chosen from cullet, such as household cullet or laminated glass cullet, waste fibers or mineral wools, and a combination of at least two of these materials.

4. Composition according to one of claims 1 to 3, characterized in that the recycling materials comprise at least 30%, preferably at least 50%, by weight of a recycling material having an LOI of at least 0.05%, preferably at least 0.1%, or even at least 0.5%.

5. Composition according to one of claims 1 to 4, characterized in that said CB content and said loss on ignition LOI are such that: [Eq 6] LOI • (1+0.37Cb)

6. Composition according to one of claims 1 to 5, characterized in that the glass produced has a composition, expressed in the form of oxides, comprising the following constituents: SiO2 30 to 80%, A12O3 0 to 30%, CaO+MgO 2 to 45%, Na2O+K2O 0 to 30%, Fe2O3 0 to 20%, and B2O3 0.5 to 14%.

7. Composition according to one of claims 1 to 6, characterized in that the glass produced has a composition, expressed in the form of oxides, comprising the following constituents, in percentages by weight: - SiO2: 50 to 75%, preferably 60 to 70%, - Na2O: 10 to 25%, preferably 10 to 20%, - CaO: 5 to 15%, preferably 5 to 10%, - MgO: 1 to 10%, preferably 2 to 5%, - CaO and MgO together preferably representing 5 to 20%, - B2O3: 0.5 to 14%, - A12O3: 0 to 8%, preferably 1 to 6%, - K2O: 0 to 5%, preferably 0.5 to 2%, - Na2O and K2O together preferably representing 6 to 20%, - Fe2O3: 0 to 3%, preferably less than 2%, more preferably less than 1%.

8. Composition according to one of claims 1 to 6, characterized in that the glass produced may have a composition, expressed in the form of oxides, comprising the following constituents, in percentages by weight: - SiO2: 65 to 80%, preferably 70 to 75%, - Na2O: 5 to 20%, preferably 8 to 15% - CaO: 5 to 20%, preferably 8 to 15% - A12O3: 0 to 10%, preferably less than 5% - MgO: 0 to 5%, preferably less than 3%, - B2O3: 0.5 to 14%, - Fe2O3: 0 to 2%, preferably less than 1%.

9. Composition according to one of claims 1 to 8, characterized in that the CB content is from 1 to 12%, from 2 to 10%, from 5 to 14%, from 7 to 13%, from 8 to 12%, from 1 to 7%, from 4 to 7%, from 0.5 to 7%, from 1.5 to 6%, or from 1.5 to 3.5% by weight.

10. A process for producing glass having a boron CBen content, expressed as B2O3, of 0.5 to 14% by weight, comprising the following steps: - feeding a furnace with a raw material composition as defined in any one of claims 1 to 9; and - melting said composition in the furnace to obtain a bath of molten material.

11. Method according to claim 10, characterized in that the furnace is an at least partly electric melting furnace.

12. Method according to claim 10, characterized in that the furnace is a hybrid melting furnace.

13. A method of manufacturing a mineral wool comprising: - the feeding and melting steps of the glass production process as defined in any one of claims 10 to 12, making it possible to obtain a bath of molten material, and - the fiberization of said bath of molten material, preferably by internal centrifugation.

14. Glass obtained by the production process as defined in any one of claims 10 to 12.

15. Glass according to claim 14, in the form of cullet having a d50 of between 1 and 50 mm, preferably between 1 and 25 mm, better still between 1 and 10 mm, or even between 1 and 5 mm.

16. Mineral wool obtained by the manufacturing process as defined in claim 13.