Preparation of raw material composition

Abstract

A method for preparing a raw material composition suitable for being fed into the melting chamber of a plant suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass is provided. The method comprises grinding a mixture of mineral wool suitable for inclusion in a raw material composition, so that the granular mixture obtained after grinding has a density of 30 kg / m 3 The method is characterized by including at least one step of making the material have an apparent density of at least 1000 kJ / cm2.

Description

[Technical Field]

[0001] The present invention relates to a method for preparing a raw material composition suitable for firing in a glass furnace. The invention further relates to the raw material composition thus obtained, and to a method for melting this composition. Finally, the invention relates to a method for producing cullet, glass wool and / or rock wool, textile glass yarns and / or flat glass, or hollow glass (bottles, flasks, etc.), or such a method for production following said melting method. Summary of the Invention

[0002] More specifically, the raw material composition according to the present invention is obtained from a mineral wool mixture. Within the meaning of the present invention, such a mineral wool mixture contains one or more types of mineral fibers, originating from the production of the fibers (factory waste), from the construction site (construction or demolition site waste), and / or from recycling channels that allow the recovery of such fibers from the final product, regardless of whether they were used or not. In fact, the various stages of mineral wool production generate a certain amount of waste, which enters into the composition of the mineral wool mixture. This waste may result, for example, from the cutting of finished products (and / or discarded products) and therefore may contain a large amount of organic material, such as resins called "binders" and intended to ensure the mechanical bonding of the fiber mat. Other types of materials can be combined with the mineral fibers, examples of which are paper, aluminum or bituminous film, or wooden pallet parts. Such mineral fibers may consist, in particular, of glass and / or rock. They are therefore known as glass wool and rock wool, respectively. These mineral fibers are usually combined with organic binders and other metallic and / or organic materials.

[0003] In this context, it is known to "recycle" such mineral wool mixtures by melting them in a glass furnace, so as to produce cullet, in other words mineral material suitable for use as a vitrifiable raw material in a subsequent glass melting process, as described in the text of patent EP 1 771 391 B1. Among the many advantages of such recycling of mineral wool waste is an improvement in the energy efficiency of the glass furnace, since the collected mineral wool mixtures and / or cullet resulting from their melting are easier to melt than "traditional" raw material compositions, which contain, inter alia, large amounts of silica.

[0004] Despite these advantages, the inventors have found that such mineral wool mixtures occupy a considerable volume when introduced into a furnace, for example, via a screw feeder. For a given feed volume, the use of a feed composition consisting of such a mineral wool mixture tends to significantly reduce the mass of raw material introduced into the furnace per unit of time, compared to so-called "traditional" feed compositions. In other words, the use of such mineral wool mixtures as raw material therefore reduces the feed rate of the furnace and therefore its efficiency, which may prove to be a prohibitive disadvantage in an industrial context.

[0005] A natural solution to this technical problem is to increase the capacity of the raw material supply means, for example by using a larger screw feeder, but this solution is not without drawbacks, since it requires structural modifications of the feeder, the size of which, more generally, becomes dependent on the nature of the composition being fed.

[0006] The claimed invention aims to provide a technical solution to the drawbacks described above. More particularly, in at least one embodiment, the proposed technology relates to a method for preparing a raw material composition suitable for being fed into a melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, said method comprising grinding a mineral wool mixture suitable for inclusion in the raw material composition, so that the granular mixture obtained after grinding has a density of 30 kg / m 3 The method is characterized by including at least one step of making the powder have a bulk density of at least 1000 kJ / g.

[0007] Throughout this specification, the term "bulk density" refers to the mass of a crushed mixture per unit of total volume, including the voids separating the aggregates (grains) that make up this mixture. For the purposes of this invention, this bulk density is measured according to the procedure described herein or by any procedure that makes it possible to obtain equivalent results.

[0008] The mineral wool mixture to be ground contains one or more types of mineral fibers, originating from the production of said fibers, from building sites (construction or demolition) and / or from recycling channels that allow the recovery of such fibers from the final product, regardless of their use. Such mineral fibers may consist in particular of glass and / or rock. They are therefore known as glass wool and rock wool, respectively.

[0009] The preparation method according to the present invention allows the bulk density of the mineral wool mixture to be increased by grinding, thus obtaining a granular mixture that can be fired in so-called "conventional" glass furnaces at a satisfactory feed rate. As detailed herein, the use of such a granular mixture makes it possible to achieve feed rates of 5 tons or more per day, especially under standard feed conditions below the level of the glass melt. The selection of such a minimum value for bulk density takes into account, in particular, the empirically observed difference between the theoretical value of the feed rate and the actual value of such rate measured under standard operating conditions.

[0010] According to a particular embodiment, the resulting granular mixture has a density of 50 kg / m 3 More than 70 kg / m 3 More than 90 kg / m 3 or more, preferably 100 kg / m 3 It has a bulk density of 1000 or more.

[0011] Increasing the bulk density of the granular mixture increases the furnace feed rate and therefore furnace productivity.

[0012] According to a particular embodiment, the granular mixture obtained after grinding has a powder density of 500 kg / m 3 It has the following bulk density:

[0013] As detailed herein, the implementation of melting test processes in submerged burner furnaces has revealed that above a certain value of bulk density, part of the introduced raw material composition tends to be released together with the flue gases due to its high volatility. This complicates the work of treating these gases, reduces the productivity of the furnace, and therefore represents a major industrial drawback. In this respect, as detailed herein, above 500 kg / m 3 The use of a granular mixture having the following bulk density makes it possible to maintain an acceptable flue loss rate for the granular mixture, since the rate is less than 3%.

[0014] According to a particular embodiment, the resulting granular mixture has a density of 400 kg / m3 Less than or equal to 300 kg / m 3 Less than or equal to 220 kg / m 3 It has the following bulk density:

[0015] By limiting the bulk density of the granular mixture, it is possible to reduce the flue loss rate of the raw material, thus facilitating flue gas processing.

[0016] According to a particular embodiment, the mass proportion of the granular mixture relative to the total mass of the raw material composition is 5% or more, preferably 20% or more, preferably 40% or more, preferably 60% or more, preferably 70% or more, preferably 80% or more, preferably 90% or more, preferably 95% or more, preferably 99% or more.

[0017] According to a particular embodiment, the preparation method comprises the step of adding cullet to said granulated mixture, the mass of which is equal to or greater than 1% of the total mass of the granulated mixture.

[0018] The inventors have observed that the addition of cullet to a granular mixture (i.e., after grinding) tends to modify its rheological behavior and thus facilitate its transport, especially during raw material feeding. This is called "fluidization" of the granular mixture. A minimum proportion of 1% corresponds to the minimum threshold for this fluidization effect of the granular mixture to become apparent.

[0019] The introduction of cullet has the added advantage of allowing it to be processed for further use, for example by removing undesirable compounds in an immersion burner furnace.

[0020] According to one particular embodiment, the mass of the cullet is less than or equal to 20% of the total mass of the granular mixture.

[0021] Since cullet itself is produced by melting raw materials at significant energy cost, the addition of cullet, and therefore melting, in proportions greater than 20% of the total mass of the granular mixture tends to unacceptably reduce the energy efficiency of the process as a whole.

[0022] According to one particular embodiment, the added cullet has a granularity of 1 to 5 mm.

[0023] In this document, "granularity" means the size of the agglomerates as determined by sieving. By selecting a cullet granularity range of 1 to 10 mm, the fluidization of the granular mixture by the cullet is optimized.

[0024] According to one particular embodiment, the preparation method comprises a preliminary step of determining the desired bulk density value of the ground granular mixture as a function of the dimensional characteristics of the feeder used and / or the desired feed rate value.

[0025] The method of preparing the feed composition can be adjusted by predetermining the desired density value and then using a feeder with known dimensional characteristics to achieve the desired feed rate by taking the desired density value into consideration.

[0026] According to a particular embodiment, the mineral wool mixture has a water content of more than 1% of the total mass of the mixture.

[0027] As detailed herein, a series of tests on a mill confirmed that by increasing the water content of the mineral wool mixture, it is possible to further increase the bulk density of the granular mixture obtained after grinding, independently of the mass supply associated with the addition of water. Indeed, water acts as a binder by creating capillary bridges between the fibers, which allows the fibers to bond better together.

[0028] In certain embodiments, water is provided before and / or during milling, for example by spraying.

[0029] An additional advantage of wetting the mineral wool mixture during the grinding process is that dust emissions are reduced.

[0030] According to one particular embodiment, the mineral wool mixture has a moisture content greater than 2%, preferentially greater than 3%.

[0031] Increasing the moisture content further increases the bulk density of the granular mixture. When the granular mixture is conveyed on a belt, the upper limit of 25% corresponds to a threshold above which the granular mixture tends to adhere to the conveyor belt, thus clogging and / or damaging it.

[0032] According to one particular embodiment, the preparation method uses at least one grinder equipped with a screen having a mesh size of less than 20 mm.

[0033] By selecting such a mesh size, the 3 It is possible to obtain a granular mixture having a bulk density of at least 10 ...

[0034] According to one particular embodiment, the mesh size of said screen is less than 20 mm, preferably less than 15 mm, preferably less than 10 mm.

[0035] Selection of smaller and smaller mesh sizes results in granular mixtures with higher and higher densities.

[0036] According to one particular embodiment, the grinder is adapted to rotate at a speed greater than 150 rpm, preferably greater than 175 rpm, more preferably greater than 200 rpm.

[0037] The yield of a grinder tends to increase with the rotational speed of its drum.

[0038] According to one particular embodiment, the ground mineral wool mixture comprises, excluding adhesive, the following: SiO2: 30~75% by mass, CaO+MgO: 5~40% by mass, Al2O3: 0~30% by mass, Na2O+K2O: 0~20% by mass, Iron oxide: 0 to 15% by mass.

[0039] According to one particular embodiment, the crushed mineral wool mixture consists of rock wool (also called "black glass" by those skilled in the art), which, apart from the adhesive, comprises: SiO2: 30~50% by mass, Al2O3: 10~22% by mass, CaO+MgO: 20~40% by mass, Iron oxide: 3 to 15 mass % Na2O+K2O: 1~10% by mass.

[0040] According to one particular embodiment, the ground mineral wool mixture consists of glass wool, which, apart from the adhesive, comprises: SiO2: 50~75% by mass, Al2O3: 0~8% by mass, CaO+MgO: 5~20% by mass, Iron oxide: 0 to 3 mass% Na2O+K2O: 12~20% by mass, B2O3: 2~10% by mass.

[0041] According to one particular embodiment, the ground mineral wool mixture comprises, excluding adhesive, the following: SiO2: 39~44% by mass, Al2O3: 16~27% by mass, CaO: 6~20% by mass, MgO: 1~5% by mass, Na2O: 0~15% by mass, K2O: 0~15% by mass, Na2O+K2O: 12~20% by mass, P2O5: 0~3% by mass, Fe2O3:1.5~15% by mass B2O3: 0~2% by mass, TiO2: 0~2% by mass.

[0042] The present invention further relates to a raw material composition suitable for being fed into the melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarns, flat glass and / or hollow glass, preferably obtained by such a preparation method, having a melting point of 30 kg / m 3 The present invention relates to a raw material composition comprising a granular mixture having a bulk density of at least 1000 kJ / g.

[0043] According to a particular embodiment, the granular mixture has a density of 50 kg / m 3 More than 70 kg / m 3 More than 90 kg / m 3 or more, preferably 110 kg / m 3 It has a bulk density of 1000 or more.

[0044] According to a particular embodiment, the granular mixture has a density of 500 kg / m 3 Less than 400 kg / m 3 Less than or equal to 300 kg / m 3 Less than 200 kg / m 3 or less, preferably 160 kg / m 3 or less, preferably 140 kg / m 3 It has the following bulk density:

[0045] According to certain embodiments, the feed composition comprises at least 30% by weight of the granular mixture, preferably at least 60% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, even more preferably at least 98% by weight of the granular mixture.

[0046] According to a particular embodiment, the raw material composition comprises cullet in an amount of at least 1% by weight of the total weight of the granulated mixture.

[0047] According to one particular embodiment, the mass of the cullet is less than or equal to 20% of the total mass of the granular mixture.

[0048] The invention further relates to a process for melting such raw material compositions to obtain cullet, glass wool and / or rock wool, textile glass yarns and / or flat / hollow glass.

[0049] According to a particular embodiment, the feed composition is fed by a feed screw, preferably from a buffer silo containing the feed composition.

[0050] Compared to a piston operating in a feed cycle, an endless screw allows for continuous feeding, which is particularly useful when feeding below the level of the glass melt.

[0051] The use of a buffer silo, preferably equipped with a scale at the outlet, makes it possible to precisely regulate the mass delivered to the feeder.

[0052] In certain embodiments, the feed composition is fed at a feed rate of 5 tons or more per day.

[0053] According to a particular embodiment, the feed composition is fed at a feed rate of at least 7 tonnes per day, preferably at least 9 tonnes per day, preferably at least 10 tonnes per day.

[0054] Since the overall yield of the furnace increases with the feed rate, it is of interest to increase it, and the use of a feed composition according to one of claims 7 and 8 makes it easier to achieve such feed rate values.

[0055] According to certain embodiments, the bulk density of the granular mixture is measured periodically, manually and / or automatically.

[0056] According to certain embodiments, the bulk density of the granular mixture is adjusted manually and / or automatically depending on the desired feed rate.

[0057] According to a particular embodiment, the raw material composition is fed below the level of the glass melt, and preferably the melting method uses a melting chamber equipped with immersion burners.

[0058] As used herein, the terms "water glass" and "glass melt" refer to the molten product of these vitrifiable materials introduced into a glass furnace. For the purposes of the present invention, "submerged burners" are burners configured so that the flame they produce and / or the combustion gases they produce are generated within the glass melt itself. Typically, they are positioned flush with the bottom, so that the flame is generated within the mass of vitrifiable material that is liquefying (molten). They may therefore pass through its side walls, bottom wall, and / or be suspended from above by suspending them from a vault or any suitable superstructure. These burners may be such that their gas supply lines are flush with the walls through which they pass. It may be preferable for these ducts to at least partially "enter" the mass of vitrifiable material to avoid the flame being too close to the wall, causing premature wear of the refractory material. It is also possible to choose to inject only combustion gases, with combustion being carried out outside the melting chamber itself.

[0059] The use of submerged burner furnaces allows for a significant increase in production yield compared to "traditional" melting. In fact, melting with a submerged burner creates convective mixing within the liquefied vitrifiable material. This mixing of the not-yet-liquefied material with the already molten material is highly efficient, allowing melting of vitrifiable material of the same chemical composition to occur at lower temperatures and / or much faster than with conventional heating means. In this way, the highly desirable characteristics of a "stirred" melt are achieved without the need to rely on unreliable and / or rapidly wearing mechanical stirring means. This is of great interest not only for the reduction of furnace energy costs, but also for the selection of refractory materials used in the construction of the equipment, since they do not heat up as much and corrode as quickly.

[0060] According to a particular embodiment, the raw material composition is fed above the level of the glass melt, and preferably the melting method uses a melting chamber equipped with a flame burner positioned above the level of the glass melt.

[0061] An advantage of feeding the raw material composition above the level of the glass melt is that organics present in the composition can be burned before they are introduced into the glass melt, thus limiting contamination of the glass melt while utilizing the additional energy source that these organics constitute.

[0062] In this context, reducing the thickness of the batch supplied to the surface of the glass melt facilitates its melting while limiting the risk of particles escaping through one or more stacks. Therefore, the composition according to the invention is particularly suitable, since it has a reduced volume and therefore a reduced thickness for an equivalent mass.

[0063] The invention further relates to a method for producing cullet, glass and / or rock wool, textile glass yarn, flat glass and / or hollow glass, including such a melting method.

[0064] As discussed in this document, the implementation of such a melting method makes it possible to achieve particularly advantageous manufacturing yields.

[0065] The invention further relates to cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass obtainable according to such a manufacturing method.

[0066] Further features and advantages of the present invention will become apparent from the following description of particular embodiments, given purely as illustrative and non-limiting examples, and from the accompanying FIG. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a flow chart illustrating a method for producing cullet, glass wool and / or rock wool, textile glass yarn, flat glass, and / or hollow glass, according to certain embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0068] Throughout this specification, including FIG. 1, identical reference numbers represent similar or identical elements unless otherwise indicated.

[0069] It is further understood that the present invention is in no way limited by the specific embodiments described and / or represented, and that other embodiments are entirely possible.

[0070] Figure 1 is a flow diagram illustrating a method for producing glass products (5) according to certain embodiments of the present invention. In conventional methods, raw materials (4), derived at least in part from a mineral wool mixture (1), are fed into a glass furnace (step S3), melted (step S4), and then processed into glass products (5).

[0071] According to known methods, the molten mixture can alternatively be cooled and fragmented to obtain cullet, formed into fibers to obtain glass wool or rock wool, spun into glass textile yarns, and / or poured onto a tin float to obtain flat glass, each of these industrial applications being referred to throughout this specification by the expression "glass product (5)".

[0072] According to a particular embodiment of the invention, such a manufacturing method comprises melting a raw material composition (4) obtained at least in part from a granular mixture (2), the bulk density of which is 30 kg / m 3 That's all.

[0073] According to an easily reproducible procedure for measuring the bulk density of a granular mixture (2), the granular mixture is first poured into a container, for example a bucket, of known mass and volume. The container must be at least 20 liters in size in order to have sufficient accuracy and to respect the aspect ratio that limits the settling of the mixture by satisfying the following formula:

[0074]

number

[0075] It is also important to ensure that the mixture is poured gently, without moving the bucket or mechanically compacting the mixture, to minimize settling of the mixture. The filled bucket is then weighed to determine the mass of the poured mixture. Bulk density is the ratio of the measured mass of the mixture to the volume of the bucket.

[0076] It should be noted that this method of characterizing bulk density is significantly more accurate and precise than any alternative method that simply estimates the size of fiber aggregates, also known as "flakes." In fact, any mineral wool mixture (1) can be viewed as an expandable or compressible volume of mineral fiber aggregates, which can itself be divided into multiple aggregates of smaller and / or less dense fibers. Therefore, in the absence of additional information, the size of the mineral fiber aggregates cannot be used as data to characterize a product and / or to compare two products.

[0077] In order to more accurately assess the value of the glass feed rate as a function of the variations in the various operating parameters of the furnace and the bulk density of the charged composition, we have set the glass feed rate at 20 kg / m 3 and 110 kg / m 3 A test run was carried out conveying two batches of glass wool waste with bulk densities of 10 ...

[0078] Two types of tests were performed: - "Cold" test, where a screw feeder is fed with glass wool waste for a predetermined period of time, which is then collected at the outlet of the feeder and weighed to estimate the mass flow rate of the feeder. - so-called "hot" tests, in which the same batch feeder is placed at the entrance of an operating melting furnace. A known mass of waste is fed, the time taken to feed this total amount is recorded and the feed rate is calculated.

[0079] For both tests, the endless feed screw has a pitch and diameter of 30 cm. The filling rate is 100% and the filled screw input hopper ensures constant feeding.

[0080] In parallel with these two industrial tests, theoretical feed rate values ​​were calculated under the same operating conditions based on the following formula, which gives an estimate of the feed rate Q (kg / s) delivered by the screw: Q=r * d * V* π * R 2* H (where r is the screw filling speed, d is the density of the mixture fed (kg / s), and V is the rotation speed of the endless screw (s -1 (10 rpm under standard feeding conditions), R is the screw radius (m), and H is the screw pitch (m).

[0081] Table 1 below shows the results obtained for four glass wool samples with different bulk densities, which were fed into a furnace via an endless screw at different screw rotation speeds. [Table 1]

[0082] Negligible differences are observed when comparing the theoretical feed rate values ​​with the results obtained in low-temperature tests. Therefore, the screw transport theory (theoretical values) can give a relatively accurate estimate of the low-temperature results.

[0083] On the other hand, when comparing the theoretical values ​​of the feed rates with the results obtained by tests carried out at high temperature conditions, a surprising significant decrease in the feed rate is observed, of 20% to 40% of the theoretical value. Several hypotheses can possibly justify such empirically observed differences in values, including the pressure exerted by the glass melt on the incoming mixture and / or the rise of combustion gases from the furnace, which then occupy part of the available space of the screw.

[0084] Taking such discrepancies into account, it is directly applicable to industrial reality. For example, it is generally accepted that for reasons of profitability of a melting furnace, the minimum feed rate of raw material into the furnace should be 5 tons per day, i.e., 208 kg / h. If a person skilled in the art adheres to theory or to the results obtained in cooling tests, i.e., tests that are significantly easier to carry out than high-temperature tests, it is possible to conclude that under standard loading conditions, a minimum feed rate of 20 kg / m3 It will be concluded that the use of glass wool waste with a bulk density of 232 kg / hour is sufficient to obtain a feed rate of 232 kg / hour, i.e. a satisfactory rate.

[0085] However, this is not the case. High temperature tests carried out on sample number 1 (see Table 1) show that the actual feed rate achieved is 150 kg / m 3 This means that the flow rate is far below the established standard.

[0086] For equivalent operating conditions, taking into account a maximum deviation of 40%, 208.8 kg / m 3 , i.e., the bulk density required to obtain a feed rate nearly equal to the set minimum threshold is in fact 30 kg / m 3 is.

[0087] Obtaining this threshold value for bulk density is not trivial, as it is the result of a series of complex (high temperature) tests carried out by the inventors.

[0088] To increase the bulk density of the granular mixture, the inventors carried out a test process in which three batches of glass wool waste were ground using a standard industrial production grinder, and the bulk density of the resulting granular mixture was then measured for each of these batches. The purpose of this process was, in particular, to evaluate the effect of various grinder parameters and wetting rates on the bulk density of the ground mineral wool mixture.

[0089] The first batch consisted of just the standard glass wool panels.

[0090] The second batch corresponds to this first batch plus 8.8 kg of moistened glass wool waste.

[0091] The third batch corresponds to this second batch plus 6.4 kg of moistened glass wool waste.

[0092] Based on these three batches, five (5) tests were conducted. Tests 1-3 were conducted on the first batch with different grinder settings. Test No. 4 was conducted on the second batch, and Test No. 5 was conducted on the third batch.

[0093] Table 2 below shows the results obtained from each of these tests. Unless further explained, all parameters not specified in this table are the same between each of these tests. [Table 2]

[0094] Comparing the results of tests 1 and 2, it is observed that by reducing the mesh size of the grinder screen from 15 mm to 10 mm, the bulk density of the resulting granular mixture increases by 72% and the capacity of the grinder increases by 9.6%.

[0095] Comparing the results of Tests 2 and 3, it can be seen that increasing the drum rotation speed from 150 to 210 revolutions per minute (rpm) increases the bulk density of the resulting granular mixture by 6.5%.

[0096] Comparing the results of Tests 1 and 4, it can be seen that the addition of wet waste material to the ground glass wool mixture increases the bulk density of the resulting granular mixture and the capacity of the grinder. This is confirmed by comparing Tests 4 and 5, where it is observed that increasing the proportion of wet waste further increases the bulk density of the ground mixture and the capacity of the grinder. The present disclosure includes the following inventive aspects: <Aspect 1> 1. A method for preparing a raw material composition suitable for being fed into a melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, comprising grinding a mineral wool mixture suitable for inclusion in said raw material composition, so that the granular mixture obtained after grinding has a melting point of 30 kg / m 3 Over 500kg / m 3 The method includes at least one step of causing the powder to have a bulk density of: <Aspect 2> The preparation method of aspect 1, wherein the mass proportion of the granular mixture relative to the total mass of the raw material composition is 5% or more, preferably 20% or more, preferably 40% or more, preferably 60% or more, preferably 70% or more, preferably 80% or more, preferably 90% or more, preferably 95% or more, preferably 99% or more. <Aspect 3> A method according to any one of the preceding aspects, comprising adding cullet to the granular mixture, wherein the mass of the cullet is 1% or more of the total mass of the granular mixture. <Aspect 4> 4. The method according to any one of aspects 1 to 3, comprising a preliminary step of determining a desired bulk density value of the milled granular mixture as a function of the dimensional characteristics of the feeder used and / or the desired feeding rate value. <Aspect 5> A method according to any one of aspects 1 to 4, wherein the mineral wool mixture has a water content of more than 1% of the total mass of the mixture. <Aspect 6> A method according to any one of the preceding aspects, wherein at least one grinder is provided with a screen having a mesh size of less than 20 mm. <Aspect 7> A raw material composition (4) suitable for feeding into a melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, preferably obtained by the preparation method according to any one of aspects 1 to 6, having a melting density of 30 kg / m 3 Over 500kg / m 3 A raw material composition (4) comprising a granular mixture (2) having the following bulk density: <Aspect 8> 8. The raw material composition (4) of claim 7, comprising cullet in an amount of at least 1% by weight of the total weight of the granular mixture. <Aspect 9> 9. A method of melting the raw material composition according to aspect 7 or 8 to obtain cullet, glass wool and / or rock wool, textile glass yarns and / or flat / hollow glass. <Aspect 10> Aspect 10. The melting method of aspect 9, wherein the raw material composition is fed by a screw feeder, preferably fed from a buffer silo containing the raw material composition. <Aspect 11> 11. The melting method according to claim 9 or 10, wherein the raw material composition is supplied at a supply rate of 5 tons or more per day. <Aspect 12> 12. The melting method of any one of aspects 9 to 11, wherein the raw material composition is fed below the level of the glass melt, and preferably the melting method employs a melting chamber equipped with an immersion burner. <Aspect 13> 12. The melting method of any one of aspects 9 to 11, wherein the raw material composition is provided above the level of the glass melt, and preferably the melting method employs a melting chamber comprising a burner positioned above the level of the glass melt. <Aspect 14> A method for producing cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, the method comprising the melting method according to any one of aspects 9 to 13. <Aspect 15> Cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, obtainable by the production method according to embodiment 14.

Claims

1. 1. A method for preparing a raw material composition suitable for being fed into a melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, comprising grinding a mineral wool mixture suitable for inclusion in said raw material composition, so that the granular mixture obtained after grinding has a melting rate of 30 kg / m ３ More than 500 kg / m ３ 1. A method comprising at least one step of:

2. The preparation method according to claim 1 , wherein the mass ratio of the granular mixture to the total mass of the raw material composition is 5% or more.

3. 3. The method of claim 1, further comprising adding cullet to the granulated mixture, the mass of the cullet being 1% or more of the total mass of the granulated mixture.

4. 4. A preparation method according to any one of claims 1 to 3, comprising a preliminary step of determining a desired bulk density value of the ground granular mixture as a function of the dimensional characteristics of the feeder used and / or the desired feed rate value.

5. A method according to any one of claims 1 to 4, wherein the mineral wool mixture has a water content of more than 1% of the total mass of the mixture.

6. A preparation method described in any one of claims 1 to 5, wherein in the step of grinding the mineral wool mixture, at least one grinder equipped with a screen having a mesh size of less than 20 mm is used to obtain the granular mixture.

7. A raw material composition (4) suitable for feeding into the melting chamber of an installation suitable for obtaining cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, said composition having a melting point of 30 kg / m ３ More than 500 kg / m ３ A raw material composition (4) comprising a granular mixture (2) having the following bulk density:

8. 8. The raw material composition (4) of claim 7, comprising cullet in an amount of at least 1% by weight of the total weight of the particulate mixture.

9. 9. A method for melting the raw material composition according to claim 7 or 8 to obtain cullet, glass wool and / or rock wool, textile glass yarns and / or flat / hollow glass.

10. The melting method according to claim 9, wherein the raw material composition is fed by a screw feeder.

11. 11. The melting method according to claim 9 or 10, wherein the raw material composition is supplied at a supply rate of 5 tons or more per day.

12. The melting method according to any one of claims 9 to 11, wherein the raw material composition is fed below the level of the glass melt.

13. The melting method according to any one of claims 9 to 11, wherein the raw material composition is fed above the level of the glass melt.

14. 14. A method for producing cullet, glass wool and / or rock wool, textile glass yarn, flat glass and / or hollow glass, comprising a melting method according to any one of claims 9 to 13.

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