Method and apparatus for recycling glass containing waste into glass products

Abstract

A method for recycling glass-containing waste into glass fibers, the method comprising: introducing a batch of glass raw materials at an upstream part of a heated furnace; introducing the glass-containing waste into the furnace by spraying the glass-containing waste over the surface of the melting batch of glass raw materials, within a half portion of the furnace including the upstream part; allowing the glass-containing waste and the glass raw materials to melt and flow along the furnace length and to form a molten glass; exiting the molten glass from the furnace at a downstream part of the furnace opposite the upstream part; fiberizing the molten glass into glass fibers.

Description

Method and Apparatus for Recycling G lass Containing Waste into Glass ProductsTECHNICAL FIELD

[0001] The present description relates to materials recycling technology, specifically the recycling of glass-containing waste into glass products.BACKGROUND

[0002] The management of discarded composite materials, particularly those reinforced with fibrous elements, has become a pressing issue within the materials sector. These materials are essential to a multitude of sectors due to their durability and adaptability. Nonetheless, the end-of-life treatment and reintegration of such materials into productive use remain fraught with challenges.

[0003] Conventional approaches to reprocessing these materials often result in suboptimal outcomes and may not support the retention of desirable properties in the resultant products. Additionally, the reprocessing is further complicated by the presence of non-glass constituents, varying degrees of moisture, and extraneous substances that may affect the processing behavior and the quality of the end product.

[0004] The industry has acknowledged the need for an improved method that allows for the efficient reutilization of these materials, thereby reducing environmental impact and enhancing economic viability without degrading the performance characteristics of the resulting products.SUMMARY

[0005] According to one aspect of the present description, a method for recycling glass-containing waste (or glass-product waste) into glass fibers includes introducing a batch of glass raw materials at an upstream part of a heated furnace; introducing the glass-containing waste into the furnace byspraying the glass-containing waste over the surface of the melting batch of the glass raw materials, within a half portion of the furnace including the upstream part, i.e. a first half portion of the furnace; allowing the glasscontaining waste and glass raw materials to melt and flow along the furnace length and form a molten glass; exiting the molten glass from the furnace at a downstream part of the furnace; and fiberizing the molten glass into glass fibers.

[0006] Such a method allows to recycle a large amount of glass containing waste without degrading the quality of the molten glass and / or of the glass fibers. The glass-containing waste may be introduced after the glass bath has been formed with the batch of glass raw materials. Preferably, the furnace is a horizontal-type furnace, i.e. defining a horizontal surface of the melting batch and / or the glass bath, such as a melting basin furnace. A nonhorizontal furnace such as a shaft furnace may present limitations in view of the spraying step.

[0007] Advantageously, the glass-containing waste includes glass fiber i.e. includes or consists in waste that contains glass fiber, for example basement waste, production wastes, further processing wastes such as single end roving, multi end roving, wet use chopped strand, dry use chopped strand, fabrics, chopped strand mat, continuous filament mat, nonwoven mats / veils, wind turbine blades and / or other composites material. The glass-containing waste may comprise a single type of waste or several types of wastes mixed together.

[0008] Advantageously, the glass-containing waste introduced has a density ranging from 0.2 to 0.9 kg / m3and / or has a largest dimension of 0.5 to 50 mm of at least 80% of the fragments or particles of the glass-containing waste by number or by weight. These values allow forming an efficient spray and a rapid homogenization in the melting batch. In addition, the above dimensions may allow an efficient burning of any organic present around the glass of the glass-containing waste.

[0009] Advantageously, the method includes downsizing the glasscontaining waste through cutting and / or shredding before introducing the glass-containing waste, to obtain glass-containing waste that has the density ranging from 0.2 to 0.9 kg / m3and / or that has at least 80% by weight of the glass-containing waste with the largest dimension of 0.5 to 50 mm.

[0010] Advantageously, the method includes introducing the glasscontaining waste into the furnace by spraying the glass-containing waste for example over up to 50 % and preferably over 5 to 25% of the surface area of the surface of the melting within the half portion of the furnace. Such a range allows for an efficient melting of the glass-containing waste into the glass melt. Consequently, the glass-containing waste may be sprayed over a surface area of 25% and preferably 2.5 to 12.5% of the total open surface area of the glass bath in the furnace.

[0011] Advantageously the method includes introducing the glasscontaining waste into the furnace with a spray of at least 1 meter in length. This length may correspond to the longer distance travelled by a particle of the spray. Such a range allows for an optimized distribution of the glass-containing waste onto the melting batch. The length of the spray may be limited by an opposite wall of the furnace or by the surface of the melting batch, i.e. by the surface of the upstream half portion of the furnace. Such a spray may allow an efficient burning of organic materials if they are present in the glass-containing waste, on or above the glass melt. Further, such a spray may allow an efficient melting of the glass-containing waste or and within the melting batch.

[0012] Advantageously, the method includes introducing the glasscontaining waste with a spray generated at least partially with an oxygencontaining gas, such as air. The glass-containing waste may thus be introduced into the furnace by spraying over the surface of the melting batch in presence of oxygen or air. The gas may contribute to forming a dispersed and efficient spray as well as to burning any organic material around the glass of the glass-containing waste, on or above the surface of the melting batch.

[0013] Alternatively or in combination, an oxygen-containing gas may be introduced in the furnace at the same time of the introduction of the glasscontaining waste, for example in a direction crossing or parallel to the direction of the spray of glass-containing waste. Alternatively or in combination, the spray may be generated without using oxygen-containing gas, for example by a mechanical sprayer and / or with another gas.

[0014] Advantageously, the glass-containing waste introduced has an organic content of at most 20% by weight of the total weight of the glasscontaining waste. Such a level of organic material may be efficiently burnt in the present method, thus not affecting the melting batch. In this case, no preprocessing of the glass-containing waste to reduce the organic content is required.

[0015] Advantageously, the method includes pre-processing the glasscontaining waste for example by attrition, pyrolysis and / or solvolysis before introducing the glass-containing waste, to obtain glass-containing waste with the organic content of at most 20% by weight of the total weight of the glasscontaining waste. The pre-processing is not limited to the above and may include any other technique allowing to obtain an organic content of at most 20% by weight.

[0016] Advantageously, the glass-containing waste introduced into the furnace has a metal content that represents at most 40 mg / kg of the glasscontaining waste. Metal may affect the chemistry of the melting batch and may decrease productivity and the quality of the produced fibers.

[0017] Advantageously, the method includes removing metals from the glass-containing waste before introducing the glass-containing waste to obtain glass-containing waste with the metal content of at most 40 mg / kg of the glasscontaining waste.

[0018] Advantageously, the glass-containing waste introduced has a moisture content of at most 25% by weight of the total weight of the glass-containing waste. This avoids any drying or heating preprocessing to reduce moisture, thus saving costs and energy.

[0019] Advantageously, the method includes drying or heating the glasscontaining waste before introducing the glass-containing waste to obtain glasscontaining waste with the moisture content of at most 25% by weight of the total weight of the glass-containing waste. High moisture content may prevent forming an efficient spray and / or may decrease the productivity of the recycling method.

[0020] Advantageously, the method includes introducing the glasscontaining waste into the furnace at a weight ratio or weight flow rate ratio of 1 to 20% with regard to the batch of glass raw materials. A significant quantity of glass-containing waste may thus be recycled. A high quality of glass-containing waste, i.e. glass-containing waste fulfilling the above preferable requirements allows recycling a higher quantity of glass-containing waste.

[0021] Advantageously, the temperature in the furnace is of at least 1100°C or at least 1150°C. Higher temperature such as 1200°C, 1300 °C or more may also be used. For example, the furnace temperature in the recycling method may be close or identical to that of a glass manufacturing method without recycling glass-containing waste. The temperature may be measured at an introduction point of the glass-containing waste.

[0022] Advantageously, the method excludes calcinating the glasscontaining waste prior to introducing the glass-containing waste into the furnace. Calcination may produce dust and / or breakable particles that prevent producing high quality glass fibers. For example, calcination relates to heating the glass-containing waste before introduction into the furnace at a high temperature in presence of oxygen. For example, the temperature of calcination may be at least 600°C and the atmosphere of calcination may contain 20 or 21 % of oxygen.

[0023] According to another aspect, the disclosure relates to an apparatus for recycling glass-containing waste into glass fibers comprising afurnace including at least one batch charger adapted to feed glass raw materials into the furnace located at an upstream part of the furnace and at least one sprayer adapted to spray the glass-containing waste over the surface of the melting batch of glass raw materials and located within a half portion of the furnace including the upstream part, and at least one fiber forming device connected to a downstream part of the furnace and adapted to fiberize the molten glass. The fiber forming device may be any device known in the art such as a bushing or a spinner.

[0024] Such an apparatus is cost efficient and allow recycling a large quantity of glass-containing waste.

[0025] Advantageously, the sprayer is a pneumatic gun, a hollow screw, or a sole spreader. A simple sprayer including a funnel and compressed air may also be used.

[0026] According to another aspect, the disclosure relates to a recycling process for transforming waste-containing glass materials into glass fibers involving these steps: a. Introducing raw glass material at an initial section of a heated furnace; b. Adding the waste-inclusive glass by spraying it onto halfway through the melting batch; c. Creating molten glass into the heated furnace; d. Extracting the resulting molten glass from a section opposite and / or downstream the initial introduction point within the furnace; e. Converting the molten glass into a glass product and / or into fine glass fibers through fiberization.

[0027] According to another aspect, the disclosure relates to a method for recycling glass-containing waste into glass fibers, the method comprising:- introducing a batch of glass raw materials in an upstream side of a heated furnace;- introducing the glass-containing waste into the upstream part of furnace by spraying the glass-containing wasteover the surface of the melting batch of glass raw materials;- exiting the molten glass from the furnace at a downstream side of the furnace.

[0028] These aspects may be combined with any advantageous or preferable aspect, features or action described above. For example, the molten glass may be transformed in glass fiber or in a glass fiber product.

[0029] According to another aspect, the disclosure relates to preprocessing glass-containing waste before introduction into a recycling furnace, the pre-processing including obtaining pre-processed glass-containing waste fulfilling at least two of: a density ranging from 0.2 to 0.9 kg / m3, a largest dimension of 0.5 to 50 mm of at least 80% of the fragments number or of the weight or glass-containing waste, an organic content of at most 20% by weight, a limited metal content, for example of at most 40 mg / kg and a moisture content of at most 25% by weight. The pre-processed waste may then be used to produce glass, glass products and / or glass fibers, for example by one of the above methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further advantages and preferred embodiments of the present disclosure will become apparent from the following detailed description and drawings, in which:

[0031] Figure 1 is a top schematic view of a furnace according to the disclosure showing different introduction points.

[0032] Figure 2 is a side cross-view of another furnace of the disclosure.

[0033] Figures 3A and 3B are a top view and a side cross-view of a sprayer according to the disclosure, respectively.

[0034] Figure 4 is a side cross-view of another sprayer according to the disclosure.

[0035] Figures 5A and 5B are side cross views of yet another sprayer according to the disclosure.DETAILED DESCRIPTION

[0036] The present disclosure relates to recycling glass-containing waste into recycled glass material showing nominal performances, i.e. the performance of equivalent glass materials produced without any recycled material. Preferably, the recycled glass material includes or consists of glass fibers, for example adapted to building insulation, composite material manufacturing, filtration or textile applications.General Method

[0037] A general method according to the disclosure includes introducing glass-containing waste into a furnace at glass melting temperature, independently from the batch of glass raw materials. In the furnace, or glass melter, the glass raw materials melt due to the high heat and the glasscontaining waste may be introduced over the melting batch, i.e. the melting glass raw materials. This introduction may be performed in an upstream half part of the furnace, i.e. not further than a distance from an upstream wall or from the introduction point of the glass raw materials in the furnace equal to 50% of the furnace total length.

[0038] The glass-containing waste may be introduced through spraying, i.e. scattered in the form of particles, fragments or fibers on the melting batch. In this way, the glass-containing waste can readily melt and homogenize in the melting batch, without variation of the glass melt composition, in contrast with a simple drop off of the glass-containing waste on the melting batch. In addition, any organic material included in the glass-containing waste may be burned in the furnace, in the spray and / or on the glass melt.

[0039] At an exit point of the furnace, further processing may be performed on the obtained molten glass, such as fiberizing the molten glass into glass fibers. The glass fibers may be cut or processed as known in the art.Furnace

[0040] A furnace or glass melter in this context is a high-temperature industrial device used to melt a batch of raw materials and glass-containing waste. The furnace is designed to maintain the necessary temperatures, such as at least 1100°C or 1150°C and possibly exceeding 1300°C, to ensure the complete melting of the materials. The necessary temperatures may be obtained through gas burner(s), oil burner(s), electric heater(s) and / or hydrogen burner(s). The furnace is equipped with various components such as at least one monitoring and control device, at least one batch charger, and at least one sprayer to facilitate the melting process and the introduction of glasscontaining waste.

[0041] The furnace is preferably a horizontal-type furnace such as a melting basin furnace as shown in Fig. 1 . The depth of the glass bath (in the height direction) may be at least 400 mm, for example at least 440 mm, at least 520 mm and preferably at least 600 mm. Although the maximum depth of the glass bath is not limited, a maximum depth may be at least 1000 mm and for example up to 1400 mm, up to 1500 mm and for example up to 1600 mm. For example, the maximum total height of the furnace may be at least 3000 mm or 3200 mm and preferably 3800 mm or 4100 mm and at most preferably around 4250 mm and the depth of the glass bath may be 30 %, 45 % or 50% of the maximum total height of the furnace.

[0042] In Fig. 1 , a furnace 10 comprises an upstream part 11 and a downstream part 12 opposite the upstream part 11. An introduction point 13 for the glass raw materials may be located on the upstream part 11 , on an upstream wall 11w and / or in a doghouse 11 d located on a side of the upstream wall 11w of the furnace 10. The introduction point 13 is preferably adapted to introduce the glass raw materials horizontally in the furnace 10. The downstream part 12 comprises an exit point 14 of the molten glass. The furnace may comprise a glass bath 15, formed approximately of melting batchon the upstream side 16 of the furnace 10 and of molten glass on a downstream side 17 of the furnace 10. A virtual boundary between the upstream side and the downstream side may be between 40 and 60 % of the length of the furnace and preferably about 50% of the length of the furnace.

[0043] The furnace 10 comprises at least one waste introduction point 18, three being visible in Fig. 1. Waste introduction at the waste introduction points 18 may be performed by a sprayer. The waste introduction point(s) 18 may be above the glass bath 15, such as in a side wall, in a top wall (or crown) and / or in the upstream wall 11w of the furnace 10. The position of the waste introductions point(s) 10 and of the introduction point(s) 18 is not limited to that of Fig.1 and may be any adapted location of the upstream part 11 of the furnace 10.

[0044] In Fig. 2, the furnace 10 comprises lateral wall 10A and a top wall or crown 10B. A waste introduction point 18 is on the crown 10B and includes a simple sprayer 20 including a hopper with a concentric or side gas injection. The glass-containing waste 30 introduced in the hopper are thus pulverized by the gas 25 to form a spray 40 covering an open surface of the glass bath 15. The simple sprayer 20 may be located at any waste introduction point 18 of the furnace 10. The glass-containing waste 30 and the batch of glass raw materials are thus preferably introduced independently one from the other in the furnace 10, at two different introduction points.

[0045] The batch of raw materials refers to a specific quantity and quality of glass-forming substances that are introduced into the furnace for melting. These materials typically include silica (SiC>2), soda (Na2O), lime (CaO), and other additives that contribute to the desired properties of the final glass product. The batch is carefully measured and mixed to ensure consistent quality and performance of the molten glass. In contrast with the glasscontaining waste, the raw materials may not include any glass. The batch is introduced through the one or more batch chargers (not shown) located at the one or more introduction points 13 into the furnace 10.

[0046] Forming the molten glass bath 15 involves the process of heating the batch of raw materials and the glass-containing wastes in the furnace until they reach a liquid state i.e. a molten glass. The molten glass at the exit point 14 is a homogeneous mixture of the melted components, free from unmelted particles or impurities. The homogeneity of the glass bath 15 is essential for the subsequent steps of shaping and / or fiberizing the glass.

[0047] Fiberizing is the process of converting the molten glass into fine, continuous strands or fibers. This is typically achieved by drawing the molten glass through small orifices in a bushing, which may be a component of the furnace 10 or connected to the furnace 10 (not shown). The fibers are then rapidly cooled and solidified to form glass fibers. These fibers can be used in various applications, including reinforcement in composite materials, insulation, and other industrial uses. A spinner may also be used.Spray

[0048] Spraying refers to the method of introducing glass-containing waste into the furnace by dispersing them over the surface of the melting batch of raw materials. This is typically done using a sprayer, such as a pneumatic gun, hollow screw, or sole spreader, which ensures an even distribution of the glass-containing waste. The spraying process may involve a flow of air or oxygen to aid with the dispersion and projection of the wastes onto the melting batch as well as with the burning of organic materials that may be contained in the glass-containing waste. Preferably, the glass-containing waste is introduced in the furnace by spraying only.

[0049] A flow of oxygen-containing gas may also be introduced in the furnace, for example in a direction crossing or parallel to the spray of glasscontaining waste and optionally at a third introduction point.

[0050] Preferably, the spray 40 may be defined by a spray length, i.e. a largest distance travelled by a spray particle. This distance may be at least 1 .0 m, preferably at least 1.2 m and again preferably at least 1.5 m. In addition, atime of flight of a spray particle may be at least 0.5 s, preferably about 1.0 s and at most preferably 1 .2 s.

[0051] An open surface area of the melting batch in the furnace covered by the spayed glass-containing waste may be for example up to 50% and preferably of at least 5% of the total open surface area in the furnace, preferably at least 11 % and again preferably at least 24%. The sprayed glasscontaining waste may thus cover at least 2.5% of the open surface area of the whole glass bath 15, preferably at least 5.5% and more preferably at least 12%, for example around 25 %. At most the first half part of the open surface of the glass bath 15 including the introduction point(s) 13 (i.e. of the upstream side 16) may be covered by glass-containing waste.

[0052] Fig. 2 shows a first type of simple sprayer 20. Fig. 3A and 3B shows a sole sprayer as another type of sprayer 20. The sprayer 20 of Figs. 3A and 3B comprises a hopper 21 leading the glass-containing waste 30 to a moving element 22 under the form of a rotating wheel. The rotating wheel may comprise a horizontal base and vertical walls, in order to project through centrifuge force the particles of the glass-containing waste 30 toward an introduction tube 23 to form a spray 40. The introduction tube 23 may be partly introduced into the furnace 10.

[0053] For example, a cooling jacket 24 may be formed on at least a part of the introduction tube 23. A coolant, for example water may be circulated into the cooling jacket 24 to cool the introduction tube 23, thus contributing to an efficient spray formation and to protecting the introduction tube 23, the hopper 21 and / or the moving element 22 from heat.

[0054] Fig. 4 shows another type of sprayer 20. The sprayer 20 comprises a hopper 21 and a moving element 22 in the form of an hollow screw. Further, introduction of a gas 25 such as air is performed around or on at least a side of the introduction tube 23, for example on a bottom side to contribute to spraying. A cooling jacket 24 may also be provided on the introduction tube 23.

[0055] Figs. 5A-5B show a pneumatic gun as another type of sprayer 20. The sprayer 20 includes a hopper that may include a pusher 21 A to push the glass containing material toward the moving element 22. The moving element 22 includes a piston moving quickly from a retracted position (Fig. 5A) to an extended position (Fig. 5B) in the introduction tube 23. The pusher 21 A may move from a retracted position (Fig. 5A) to an extended position (Fig. 5B) before the movement of the moving element 22 in order to load glasscontaining waste in the introduction tube 23.

[0056] Different types of sprayers 20 may be combined onto a single furnace 10. For example, different sprayers may be adapted to different types or qualities of glass-containing waste 30. The total weight or weight flow rate of glass-containing waste 30 introduced in the furnace 10 by the sprayer(s) 20 may be up to 20 % of that of the glass raw materials introduced at the waste introduction point(s) 18.Glass-Containing Waste

[0057] The glass-containing waste can include any type of glass such as internal cullet, external cullet, glass batch fallout, rejected melts, basement waste, production wastes, further processing wastes such as single end roving, multi end roving, wet use chopped strand, dry use chopped strand, fabrics, chopped strand mat, continuous filament mat, nonwoven mats / veils, wind turbine blades and / or other composites material. The glass-containing waste may include organic materials such as a sizing or any resin. Preferably, the glass component of the glass-containing waste includes a majority or more in weight of glass fibers or consists in glass fibers. Organic material may be defined as any material outside: glass, metal and mineral material.

[0058] The glass-containing waste can include any kind of glass. Preferably, the glass-containing waste includes glass fibers, made from any type of glass. Exemplary glass fibers include, but are not limited to, A-type glass fibers, C-type glass fibers (e.g. wool glass fibers), E-type glass fibers, S- type glass fibers, ECR-type glass fibers (e.g., Advantex® glass fiberscommercially available from Owens Corning of Toledo, Ohio and defined in WO96 / 39362), Hiper-tex® glass fibers, high-performance (i.e., high modulus and / or tensile strength) glass fibers (i.e. H-glass or HP-glass), and combinations thereof.

[0059] Depending on the type, origin and condition of the glasscontaining waste, processing of the glass-containing waste may be required.

[0060] The size of the particles or fragments of glass-containing waste before introduction into the furnace may be 0.5 to 50 mm, preferably 5 to 45 mm, again preferably 10 to 30 mm. The size may be defined as the largest dimension of a single particle or fragment. If required, the glass-containing waste may be processed though a shredder and / or a cutter in order to reduce the size to the above ranges. Any particle below 0.5 mm may be discarded or removed through a de-dusting process, involving for example screening, air classification and / or electrostatic precipitation.

[0061] The density of the glass-containing waste may range from 0.2 to 0.9 kg / m3, for example 0.3 to 0.7 kg / m3, again preferably 0.4 to 0.6 kg / m3The density may be a tapped density, i.e. the density measured after shaking the glass-containing waste particles. If required, the glass-containing waste may be processed by a shredder and / or a cutter to reduce the size and thus the density. If required, the glass-containing waste may be processed by dedusting, wetting or granulating with additives to agglomerate the particles and thus to increase density.

[0062] The organic content of the glass-containing waste may be at most 20 w% of the total weight of the weight before spraying into the furnace, preferably at most 10 w% and again preferably at most 5 w%. The organic content may come from any coating, sizing or resin involved in the waste elements to be recycled, such as composite materials involved in renewable energy and / or aeronautics. If required, the glass-containing waste may be treated by attrition, pyrolysis, solvolysis and / or any other mean, prior to introduction into the furnace, in order to reduce organic content.

[0063] Attrition is the reduction of organic content by wear or friction, with or without water and / or additives. Pyrolysis is a thermochemical decomposition process that occurs when organic materials are heated to high temperatures, for example less than 600°C, in the absence of oxygen. This process may break down complex molecules into simpler substances without combustion. Solvolysis is a process of solvating organic material with a solvent, preferably a solvent adapted to the dissolution of the organic material.

[0064] The glass-containing waste may have a limited metal content, for example of at most 40 mg / kg of the glass-containing waste, preferably at most 27 mg / kg and again preferably at most 21 mg / kg. If required, metal may be removed from the glass-containing waste for example through a magnetic treatment. Coarse metallic particles are preferably avoided.

[0065] The glass-containing waste may have a moisture content of at most 25 w% of the total weight of the glass-containing waste before introduction into the furnace, preferably at most 15w% and more preferably at most 10 w%. If required, the glass-containing waste may be dried or heated in order to reduce moisture content. If an active drying or heating step is performed, moisture content may be reduced to at most 5w%, preferably at most 3 w% and more preferably at most 1w%.Examples

[0066] According to Example 1 , basement wastes of Advantex® fiber glass were introduced by a waste introduction point 18 located on the crown using a simple sprayer 20 (see Fig. 2). The basement wastes were preprocessed by shredding to obtain a density of 0.6 kg / m3The moisture content was kept unchanged at 10% by weight and the metallic content was less than 20 ppm. The organic content was 1 % by weight, only comprising the sizing. The furnace temperature was 1450 to 1600 °C as measured by several sensors placed on the crown of the furnace.

[0067] The above glass-containing waste has been introduced in a heated furnace producing Advantex® glass, after having formed a glass bathwith a batch of glass raw materials, at a mass ratio of 7.5% with regard to the batch of glass raw materials. No safety impact (i.e. no dust, explosion, or gas emission) linked with the introduction of the glass-containing waste was measured on the glass bath inside the furnace. Glass fibers were obtained from the molten glass with a bushing and the chemical composition of the glass fibers was checked.

[0068] The glass composition was identical to that of Advantex® glass fibers, thus ensuring an identical performance. Further, the number of breaks in the bushing was evaluated overtime and was identical or similar to a normal process of Advantex® glass manufacturing, i.e. without glass-containing waste.

[0069] According to Example 2, glass fiber material recovered from customers was used as glass-containing waste, after preprocessing with a shredder to obtain a density of 0.33 kg / m3The glass fiber material was a mixture of different glasses including Advantex® and H-glass that are chemically compatible with Advantex® glass (in particular excluding boron). The moisture content was 5 % by weight and the metallic content was less than 20 ppm. The organic content was 1 .5 % by weight, only comprising the sizing. The above glass-containing waste have been introduced in a heated furnace with a hollow screw (see Fig. 4) located on an introduction point located on the upstream wall 11w and with injection of air, at a mass ratio of 7%. The furnace temperature was 1450 to 1600 °C as measured by several sensors placed on the crown of the furnace.

[0070] The batch of glass raw materials was adapted to produce Advantex® glass and was introduced beforehand. In spite of the glasscontaining waste including other glass than Advantex® glass, Advantex® glass was produced showing an expected chemical composition. No impact was measured on the molten glass exited from the furnace and no safety impact was recorded. Glass fibers were obtained from the molten glass with a bushingand the glass fibers had the same performances as Advantex® glass glass fibers without wase recycling.

[0071] According to Example 3, a trial similar to that of Example 2 was performed, but the density of the glass-containing waste was 0.12 kg / m3Nominal Advantex® glass was produced but productivity was non-optimal since the mass ratio of glass-containing waste was below 2% of the mass of glass-containing waste i.e. lower than that of Examples 1 and 2.

Claims

CLAIMS1. A method for recycling glass-containing waste into glass fibers, the method comprising: a. introducing a batch of glass raw materials at an upstream part of a heated furnace; b. introducing the glass-containing waste into the furnace i. by spraying the glass-containing waste over the surface of the melting batch of glass raw materials, ii. within a half portion of the furnace including the upstream part; c. allowing the glass-containing waste and the glass raw materials to melt and flow along the furnace length and to form a molten glass; d. exiting the molten glass from the furnace at a downstream part of the furnace opposite the upstream part; e. fiberizing the molten glass into glass fibers.

2. The method of claim 1 , wherein the glass-containing waste includes glass fiber.

3. The method of claim 1 or 2, wherein the glass-containing waste introduced into the furnace has a density ranging from 0.2 to 0.9 kg / m3and / or has at least 80% by weight of the glass-containing waste with a largest dimension of 0.5 to 50 mm.

4. The method of claim 3, wherein the method includes downsizing the glass-containing waste through cutting and / or shredding to obtain glasscontaining waste that has the density ranging from 0.2 to 0.9 kg / m3and / or that has at least 80% by weight of the glass-containing waste with the largest dimension of 0.5 to 50 mm.

5. The method of any of claims 1 to 4, wherein introducing the glasscontaining waste into the furnace includes spraying the glass-containing waste over 5 to 25 % of the surface area of the open surface of the melting batch, within the half portion of the furnace.

6. The method of any of claims 1 to 5, wherein the method includes introducing the glass-containing waste into the furnace with a spray of at least 1 meter in length.

7. The method of any of claims 1 to 6, wherein the method includes introducing the glass-containing waste with a spray generated with an oxygen-containing gas.

8. The method of any of claims 1 to 7, wherein the glass-containing waste introduced in the furnace has an organic content of at most 20% by weight of the total weight of the glass-containing waste.

9. The method of claim 8, comprising pre-processing the glass-containing waste by attrition, pyrolysis and / or solvolysis to obtain glass-containing waste with the organic content of at most 20% by weight of the total weight of the glass-containing waste.

10. The method of any of claims 1 to 9, wherein the glass-containing waste introduced in the furnace has a metal content of at most 40 mg / kg of the glass-containing waste.

11. The method of claim 10, comprising removing metals from the glasscontaining waste to obtain glass-containing waste with the metal content of at most 40 mg / kg of the glass-containing waste.

12. The method of any of claims 1 to 11 , wherein the glass-containing waste introduced in the furnace has a moisture content of at most 25% by weight of the total weight of the glass-containing waste.

13. The method of claim 12, wherein the method includes drying or heating the glass-containing waste to obtain glass-containing waste with the moisture content of at most 25% by weight of the total weight of the glass-containing waste.

14. The method of any of claims 1 to 13, wherein in introducing the glasscontaining waste into the furnace, the glass-containing waste are introduced at a weight ratio or weight flow rate ratio of 1 to 20% with regard to the batch of glass raw materials.

15. The method of any of claims 1 to 14, wherein the temperature of the furnace is of at least 1100°C.

16. The method of any of claims 1 to 15, wherein the method excludes calcinating the glass-containing waste prior to introducing the glasscontaining waste into the furnace.

17. An apparatus for recycling glass-containing waste into glass fibers, the apparatus comprising: a) a furnace comprising :I. at least one batch charger to feed glass raw materials into the furnace located at an upstream half part of the furnace andII. at least one sprayer to spray the glass-containing waste over the surface of the melting batch of glass raw materials and located within a half portion of the furnace including the upstream part, b) at least one fiber forming device connected to a downstream part of the furnace opposite the upstream part, to fiberize the molten glass.

18. The apparatus of claim 17, wherein the sprayer is a pneumatic gun, a hollow screw or a sole spreader.

Images