Method and system for preparing a vitrifiable mixture

Abstract

A first aspect of the invention relates to a system for the in-line preparation of a vitrifiable mixture having a target composition, the system comprising: - a unit for dispensing raw materials, which is able to provide a premix comprising cullet, preferably at least 20% by weight of cullet; - a conveyor which is able to move the premix; - a unit for the in-line measurement of the composition of the premix by neutron activation, the in-line measurement unit comprising: • at least one neutron emission source configured to irradiate all or part of said premix; • at least one gamma ray detector configured to detect the gamma rays emitted by the premix when it is irradiated by the neutron emission source; and • a digital processing device configured to calculate, from the signal of the gamma ray detector, the content of chemical elements present in the premix, and optionally configured to estimate the water content and / or the content of organic compounds in the premix; and - at least one means for adjusting the premix to obtain the vitrifiable mixture having the target composition. The invention also relates to a method for the in-line preparation of a vitrifiable mixture having a target composition.

Description

Description Title of the invention: Process and system for preparing a vitrifiable mixture. TECHNICAL FIELD

[0001] The invention relates to the field of glass production, particularly from recycled raw materials such as cullet. More specifically, the present invention relates to a process for preparing a vitrifiable mixture comprising cullet, as well as a system for preparing such a mixture. TECHNOLOGICAL BACKGROUND

[0002] The manufacture of glass products involves melting a mixture of different mineral raw materials that make up glass, including cullet and other raw materials, particularly those from mining (silica, alkali or alkaline-earth carbonates, etc.). These raw materials are introduced in specific proportions depending on the desired chemical composition, which gives the glass the properties and / or quality sought (colored or clear glass, glass for mineral fibers, heat resistance, chemical resistance, transmission of certain wavelength ranges, etc.).

[0003] Recycled mineral glass, also known as cullet, is made from glass waste and is used as a substitute for some of the usual mining raw materials to reduce the environmental impact of the glass industry. Indeed, using recycled mineral glass decreases the use and extraction of mineral resources, reduces the energy required for melting and reacting raw materials, and reduces carbon dioxide emissions resulting from the reaction of mining raw materials (recycled glass requires less energy and emits fewer pollutants than virgin raw materials during the glass manufacturing process).

[0004] Cullet is a mixture of glass fragments that can have very different colors and compositions. In addition, cullet may contain a greater or lesser amount of contaminants, such as residues of organic and / or inorganic layers on the surface of certain glass fragments, or various debris from foreign bodies (such as ceramics, earthenware, porcelain, terracotta, (plastics, metals, electronic components, etc.) – Thus, there is a wide variety of cullet, of varying qualities, depending on its origin or treatment processes (possible cleaning, sorting, and contaminant removal steps). Two main types of cullet are distinguished: - so-called "internal" cullet consists of glass waste from a glass manufacturing process and generally includes defective products detected and rejected during quality control or during adjustments to product compositions; and - the so-called "external" cullet consists of glass waste collected from consumers and / or reprocessed with the aim of recycling glass products after their use, and may include debris of very diverse compositions and a greater proportion of contaminants.

[0005] In general, "internal" cullet has a fairly well-defined composition, which facilitates the introduction of larger quantities of this type of cullet into the raw material mix. However, this type of cullet is often less readily available than "external" cullet if the goal is to increase the proportion of cullet in glass mixes. On the other hand, "external" cullet has a much more variable composition and is used on a limited scale in the raw material mix, based on cullet supplier specifications. However, these specifications are generally broad and imprecise, which does not always allow for the reliable and reproducible production of a glass composition, particularly for flat glass, that meets the defined production specifications. This results in both production losses and raw material waste.

[0006] Using cullet for flat glass production presents an additional challenge compared to bottle glass manufacturing due to stricter quality requirements, particularly regarding transparency and the absence of inclusions or defects. The use of external cullet is therefore very limited, as even low impurity levels can lead to visual defects or affect clarity, which is unacceptable for these applications. Furthermore, it can affect the fluidity and behavior of the molten mixture, making the melting and forming process more complex. In contrast, bottle glass, which can tolerate some variability in color and clarity, allows the use of more varied or lower-quality cullet. In addition to the stricter quality constraints, flat glass production requires larger furnaces with higher capacities and feed rates. in very high raw materials (in particular the furnace must be continuously fed at a rate of more than 500 to more than 1000 tonnes per day of raw materials).

[0007] Furthermore, depending on their origin, processing methods, and / or storage conditions, different cullet batches can also contain highly variable moisture content, which can disrupt the melting process. Indeed, these variations can significantly impact the proper melting and "digestion" of raw materials in the furnace, increase energy requirements, and lead to premature furnace wear. If melting parameters are not controlled, excessively high moisture content can result in incomplete melting of the cullet and / or other raw materials in the furnace, ultimately leading to a non-compliant or substandard finished product.

[0008] To meet the challenges of reducing environmental impact, it is necessary to use increasingly larger proportions of cullet in mixtures of vitrifiable raw materials, for example, above 30% by mass, or even above 50% or 70% by mass. However, such proportions require the use of larger quantities of external cullet, the variability of whose composition and batches disrupts the melting process and leads to the disposal of a significant amount of finished product, resulting in a waste of resources and energy.

[0009] There is therefore still a need to produce target glass compositions, particularly for the manufacture of flat glass, from large quantities of cullet, at high rates, while ensuring both the quality and conformity of the finished products and limiting as much as possible the number of rejects related to the variability of batches of raw materials.

[0010] It is to the applicant's credit that they have proposed a process and system for preparing a verifiable mixture of target composition which, surprisingly, makes it possible to solve these problems. SUMMARY OF THE INVENTION

[0011] According to a first aspect, the invention relates to an online preparation system for a vitrifiable mixture of target composition, particularly for the manufacture of flat glass, the system comprising: - a raw materials distribution unit capable of supplying a premix comprising cullet, preferably at least 20% by mass of cullet; - a conveyor capable of setting the premix in motion; - an online unit of measurement of the premix composition by neutron activation, the online unit of measurement comprising: • at least one source of thermal and fast pulsed neutron emission, said source being arranged and configured so as to irradiate all or part of said premix; • at least one gamma ray detector configured to detect gamma rays emitted by the premix when irradiated by the neutron emission source; • a digital processing device configured to calculate, from the gamma ray detector signal, the chemical element content in the premix, and optionally configured to estimate the water content and / or the organic compound content in the premix; and - at least one means of adjusting the premix, in particular based on online measurement of the premix composition, to obtain the vitrifiable mixture of target composition.

[0012] According to a second aspect, the invention relates to a method for the online preparation of a vitrifiable mixture of target composition, particularly for the manufacture of flat glass, the method comprising: - the supply of a premix (1005) comprising cullet, preferably at least 20% by mass of cullet; - the conveying of the premix (1005); - online measurement of the premix composition by neutron activation, the online measurement including: • irradiation of all or part of the premix by a pulsed thermal and fast neutron emission source; • the detection of gamma rays emitted by the irradiated premix; • digital processing of the gamma ray detection signal to calculate the chemical element content in the premix, and possibly to estimate the water content and / or the organic compound content in the premix; and - the adjustment of the premix, in particular according to the online measurement of the premix composition, to obtain the vitrifiable mixture of target composition.

[0013] The invention enables the precise and very high-speed analysis of the entire premix, which involves large volumes of materials subject to compositional variations, including a significant proportion of cullet, and the corresponding adjustment, online and in real time, of the composition of the raw material mixture intended to continuously feed a glass furnace. Thus, regardless of the batches of cullet and / or raw materials used, the invention prevents large variations in the composition of the vitrifiable mixture that continuously feeds the furnace. The composition of the vitrifiable mixture has a more consistent composition, closer to the target composition over time, and makes it possible to obtain a glass product with the desired properties and / or qualities while minimizing defects and rejects in the finished product.In particular, the overall chemical composition of the glassable mixture is substantially the same at the furnace inlet, despite variations in the composition of the cullet batches and / or the batches of raw materials used. This allows for a substantial increase in the proportion of cullet used in the total raw material mixture, and especially in the proportion of external cullet, which is more variable, without negatively impacting the final composition of the glass and the desired qualities. Furthermore, the present invention optimizes the furnace energy required for the proper melting of these raw materials, taking into account variations in chemical elements and moisture content. Finally, the invention offers the advantage of being able to process, potentially online, the raw material mixture used based on the detection of foreign bodies, specific contaminants, and / or moisture.Thus, the entire process is regulated and the risks of rejection are greatly reduced (glass defects linked to variations in composition and / or imperfect melting of raw materials).

[0014] The system according to the first aspect of the invention and the method according to the second aspect of the invention can be advantageously used in a process for manufacturing a glass product, for example a flat glass. DETAILED DESCRIPTION

[0015] The system and method according to the invention include the supply of a premix comprising cullet, preferably at least 20% by mass of cullet.

[0016] For the purposes of this invention, "premix" means a preliminary mixture of materials, particularly minerals, including cullet, intended to be incorporated into the composition of the vitrifiable mixture of target composition. It may be a mixture consisting of a single raw material comprising a preliminary mixture, for example, a mixture of debris such as "external" cullet. Alternatively, it may be a mixture of several raw materials, at least one of which includes cullet, for example, a mixture comprising at least two different sources of cullet, or a mixture of a source of cullet with other mineral raw materials such as mining raw materials (sand, feldspar, limestone, etc.) and / or pure oxides (SiO2, CaO, MgO, K2O, Na2O, Na2CO3, etc.).In the context of the present invention, the premix may comprise at least 20% by mass of cullet, preferably at least 30% by mass of cullet, and more preferably at least 50% by mass of cullet, relative to the mass of the premix. The premix may, for example, comprise at least 40% by mass of cullet, for example at least 70% by mass of cullet, or even 100% by mass of cullet.

[0017] Preferably, in the system or process according to the invention, the premix comprises at least two different raw materials. More particularly, the premix may comprise at least one cullet (for example, internal and / or external cullet) and at least one other raw material, in particular a mineral. Even more preferably, the premix may comprise at least one external cullet and at least one other raw material, in particular a mineral. The raw material, in particular a mineral, may be selected from sand, limestone, dolomite, feldspars, bauxite, or a mixture of these materials.

[0018] Preferably, in the system or process according to the invention, the premix represents at least 50% by mass, preferably at least 70% by mass, and more preferably at least 90% by mass of the vitrifiable mixture of target composition. The process and system according to the invention allow for the online and high-speed analysis and adjustment of the majority of the vitrifiable mixture, which makes it possible to take into account both variations in the cullet and in certain raw materials, particularly mining materials, which are also subject to variations in their composition, and to closely regulate the chemical composition of the vitrifiable mixture as a whole at the required rates.

[0019] For the purposes of this invention, a "vitrifiable mixture of target composition" means a total mixture of raw materials intended to be placed in a melting furnace to produce a glass product of predefined target composition. This mixture comprises the premix and any other raw materials added to the premix to achieve the predefined target composition (in particular, mining raw materials and / or pure oxides, but possibly also other types of cullet, including "internal" cullet).Preferably, in the system or process according to the invention, the vitrifiable mixture of target composition (i.e., the total mixture of raw materials including the premix and any raw materials added subsequently) comprises at least 30% by mass of cullet, more preferably at least 40% by mass of cullet, even more preferably at least 50% by mass of cullet, and even better at least 70% by mass of cullet, relative to the total mass of the vitrifiable mixture. "Target composition" means the target concentrations of chemical elements for obtaining a glass product of the desired composition, the composition being decisive for the desired properties of the glass product. The target compositions are of any suitable type. Preferably, the target composition is of the soda-lime silicon type. More particularly, the target composition is suitable for the manufacture of flat glass.The vitrifiable mixture of target composition is more preferentially suited to the manufacture of a glass of the following composition: - 60% to 80% by mass of SiO2, - 5 to 20% by mass of Na2O, - 5 to 20% by mass of CaO, - 0 to 10% by mass of MgO, - 0 to 10% by mass of Al2O3, - 0 to 10% by mass of K2O, preferably 0.1% to 8% by mass, - 0 to 2% by mass of iron oxide, preferably 0 to 1% by mass, - 0 to 1% by mass of boron oxide, preferably 0 to 0.5% by mass, - 0 to 5% by mass of other oxides in total.

[0020] The premix may have a different chemical composition and / or water content than the target composition vitrifiable mixture.

[0021] By "premix adjustment," we mean modifying the premix, based on online measurements of its composition, to obtain the target composition of the vitrifiable mixture. The adjustment can, for example, be carried out by adding supplementary raw materials to the premix (e.g., internal cullet of known composition, mining or synthetic raw materials, pure oxides, etc.), or by modifying the moisture content of the premix (drying or humidifying the premix). The adjustment means are configured to modify at least one property of the premix composition based on the online measurement of said composition. The adjustment means can be any device or element that allows modification of at least one property of the premix composition to obtain the verifiable mixture of target composition. For example, the adjustment means can include a dosing device that allows the controlled addition of raw materials and / or water to adjust the chemical content and / or moisture content of the mixture. The adjustment means can also include a drying system to regulate the moisture content of the mixture. Online preparation system

[0022] The online preparation system according to the invention comprises: - a raw materials distribution unit capable of supplying a premix comprising cullet, preferably at least 20% by mass of cullet; - a conveyor capable of setting the premix in motion, for example a conveyor belt; - an online unit of measurement for the composition of the premix by neutron activation, and - at least one means of adjusting the premix to obtain the verifiable mixture of target composition.

[0023] The inline preparation system according to the invention is preferably placed upstream of a glass furnace. The glass furnace can be of any suitable type (flame, submerged combustion, electric, etc.).

[0024] The inline measuring unit may be located downstream of the dispensing unit. Preferably, the inline measuring unit is located upstream of the premix adjustment means. The inline measuring unit comprises: • at least one neutron emission source configured to irradiate all or part of the premix; • at least one gamma ray detector configured to detect gamma rays emitted by the premix when irradiated by the emission source neutrons; and • a digital processing device configured to calculate, from the signal of the gamma ray detector, the content of chemical elements present in the premix, in particular the content of chemical elements with an atomic number greater than or equal to 11.

[0025] The neutron emission source(s) is / are advantageously a pulsed thermal and fast neutron emission source. The neutron emission source(s) can be of any suitable type. It can be a radioisotope source. Preferably, the neutron emission source is a sealed tube fed with Deuterium-Tritium, as described for example in document WO 00 / 03237 Al.

[0026] The gamma ray detector(s) can be of any suitable type. They may be a gas ionization detector, a scintillation detector, or a semiconductor photodetector. Preferably, in the system or method according to the invention, the gamma ray detector is a scintillation detector.

[0027] Advantageously, in the system or method according to the invention, the gamma ray detector is a spectral detector. In other words, the detector not only counts the number of detected radiations, but also measures the energy distribution of these radiations.

[0028] Preferably, in the system or method according to the invention, the gamma ray detector has an energy resolution of 4.0% or less. Energy resolution, denoted PHR (peak-to-half ratio), is the ability of a detector to distinguish two gamma rays of similar energies (standardized to the gamma isotope source energy). 137(Cs at 662 keV). The applicant highlighted that a value less than or equal to 4.0% allows for better discrimination of elements or isotopes present in the composition of glass whose peaks are very close together. Indeed, with detectors having a resolution above this value, such as bismuth germanate or "BGO" detectors, the distinction between certain elements present in the composition of glass can become more difficult (overlap of peaks that are too close or too broad), potentially leading, for example, to the erroneous attribution of the calcium signal, interpreted as originating from potassium, which is of particular importance in the field of glass. Non-limiting examples of detectors with energy resolutions less than or equal to 4.0% can be LaBr3:Ce, CeBr3 or Cs2LiLaBr6:Ce (CLLB).

[0029] Advantageously, the digital processing device can also be configured to estimate the water content and / or the organic compound content in the premix.

[0030] Preferably, the online measuring unit may further include at least one neutron detector arranged and configured to detect all or part of the neutrons emitted by the neutron emission source and transmitted through the premix, and the digital processing device is configured to calculate, from the signal of the neutron detector, variations in the kinetic energies of said neutrons passing through the premix and a water content of the premix as a function of the variations in kinetic energy.

[0031] The online preparation system according to the invention may further include a control unit configured to compare the calculated chemical element contents of the premix and / or the water content of the premix with predefined values. More preferably, the online preparation system according to the invention includes a control unit configured to compare the calculated chemical element contents of the premix with the contents of the verifiable target composition of the mixture, and optionally, configured to compare the water content of the premix with at least one predefined value. Preferably, the comparison includes calculating the difference between the calculated chemical element contents of the premix and predefined chemical element contents and / or calculating the difference between the water content of the premix and at least one predefined value.The predefined values ​​used for comparison can be, for example, target values ​​(target levels of chemical elements and / or water) or threshold values ​​(for example, a range of acceptable threshold values ​​for chemical elements and / or water). The control unit can, for example, be connected to the measuring unit, for example, to collect data calculated by the measuring unit, or it can be integrated into the measuring unit, for example, as a module integrated into the measuring unit.

[0032] The online preparation system according to the invention may further include a calculation unit configured to determine the adjustment(s) to be made to the premix, in particular based on the online measurement of the composition of the The premixing unit can be used, particularly to approximate predefined values ​​for chemical elements and / or moisture content. For example, the calculation unit can be configured to calculate the proportions of raw materials to be added to the premix to readjust the composition of the vitrifiable mixture intended for the melting furnace, based on measured levels and deviations observed when comparing them to predefined values ​​(target levels or predefined threshold values). The calculation unit can be connected to the measuring unit and / or the control unit, for example, to collect data calculated by the measuring unit and / or deviations calculated by the control unit, or it can be integrated into the control unit. The calculation unit can also be connected to a control unit to command adjustments to be made to the premix, or it can be integrated into a control unit.

[0033] The online preparation system according to the invention may further include a control unit configured to control the premix adjustment means, in particular based on the calculated chemical element contents and / or the water content of the premix. For example, the control unit may be configured to control the premix adjustment means based on data calculated by the measuring unit or based on the adjustment(s) determined by the calculation unit.

[0034] The inline preparation system according to the invention can be arranged upstream of a glass furnace and include a control unit configured to adjust at least one furnace parameter online, in particular based on the calculated chemical element content and / or the water content of the premix. Thus, the furnace parameter(s), for example, the furnace temperature, can be automatically adjusted according to the values ​​calculated by the inline measuring unit. This can be the same control unit that controls the premix adjustment means defined previously, or a separate control unit. Preferably, this control unit is also configured to control the premix adjustment means.

[0035] The control unit can, for example, be connected to one or more oven control means and / or to one or more premix adjustment means. In this way, the premix adjustment and / or the adaptation of the oven parameter(s) can be automatically ordered online, particularly based on the content of Calculated chemical elements and / or estimated water content by the online measuring unit, for example, from a signal from the measuring unit, control unit, or calculation unit. The control unit can, for example, be connected to the measuring unit, control unit, and / or calculation unit. Alternatively, the control unit can be integrated with the control unit and / or calculation unit of the preparation system according to the invention.

[0036] The premix adjustment means allow the premix to be adjusted according to the results of the online measurement unit and the target composition of the vitrifiable mixture, in particular to reduce the gap between the results of the online measurement unit and the vitrifiable mixture of target composition.

[0037] Preferably, in the online preparation system according to the invention, at least one adjustment means is chosen from among the means for adjusting the content of chemical elements and / or the means for adjusting the water content (for example, hydration or drying means) and / or the means for adjusting the content of organic compounds (for example, calcination means). Online preparation process

[0038] The online preparation process according to the invention comprises: - the supply of a premix comprising cullet, preferably at least 20% by mass of cullet, for example using a raw materials distribution unit; - the conveying of the premix, for example using a conveyor belt; - online measurement of the premix composition by neutron activation, and - adjusting the premix to obtain the vitrifiable mixture of target composition.

[0039] The inline preparation process according to the invention may further include, after the adjustment step, the inline pouring of the vitrifiable mixture of target composition obtained into a glass furnace. The glass furnace may be of any suitable type (flame, submerged combustion, electric, etc.).

[0040] The online measurement of the premix composition can be carried out using the online measurement unit as described previously. The online measurement includes: • irradiation of all or part of the premix by at least one neutron emission source, for example as described above; • the detection of gamma rays emitted by the irradiated premix, for example using at least one gamma ray detector as described above; • the digital processing of the detected signal in order to calculate the content of chemical elements present in the premix, in particular the content of chemical elements with an atomic number greater than or equal to 11.

[0041] Preferably, the digital processing of the detected signal also allows for the estimation of the water content and / or the organic compound content in the premix.

[0042] More specifically, the online measurement step may also include: • the detection of all or part of the neutrons emitted by the neutron emission source and transmitted through the premix, and • the digital processing of the neutron detection signal in order to calculate the variations in the kinetic energies of the neutrons transmitted through the premix and to calculate the water content of the premix as a function of the variations in kinetic energies.

[0043] The online preparation process according to the invention may further include, after the online measurement step of the premix composition, comparing the calculated chemical element contents of the premix and / or the water content of the premix with predefined values. Preferably, the preparation process according to the invention includes, after the online measurement step of the premix composition, comparing the calculated chemical element contents of the premix with the contents of the target composition of the vitrifiable mixture, and optionally, comparing the water content of the premix with at least one predefined value. Preferably, the comparison includes calculating the difference between the calculated contents and the predefined values.The predefined values ​​used for comparison can be, for example, target values ​​(target levels of chemical elements and / or water) or threshold values ​​(for example, a range of threshold values ​​for acceptability of chemical elements and / or water).

[0044] The online preparation process according to the invention may further include a step of determining the adjustment(s) to be made to the premix to obtain the vitrifiable mixture of the target composition. For example, the determination step may include calculating the proportions of raw materials to be introduced into the premix to readjust the composition of the vitrifiable mixture. intended to enter the melting furnace, in particular according to the measured contents and the deviations observed when comparing with predefined values ​​(target contents or predefined threshold values).

[0045] The online preparation process according to the invention may further include an online adjustment step for the parameters of a glass furnace continuously fed with the target composition glassable mixture. This adjustment step may include adjusting the furnace temperature, particularly based on calculated chemical element concentrations and / or the water content estimated by the online measuring unit, for example, following a comparison with predefined values.

[0046] Preferably, in the preparation process according to the invention, the adjustment of the premix includes the adjustment of the content of chemical elements and / or the adjustment of the water content and / or the adjustment of the content of organic compounds.

[0047] In the system or process according to the invention, the adjustment of the chemical element content is preferably achieved by adding raw materials to the premix, by modifying the flow rate of the raw materials in the distribution unit (for example, to compensate for certain raw materials relative to others), and / or by recirculating the premix back to the distribution unit (for example, to dilute the premix with other raw materials). The adjustment of the chemical element content can, for example, be achieved using the existing raw material distribution unit and / or using additional distribution unit(s). Advantageously, the adjustment of the chemical element content includes the addition of pure oxides and / or "internal" calcine.In particular, the addition of internal cullet, of known composition and adapted to the composition of the target composition vitrifiable mixture, makes it possible to further increase the proportion of cullet used in the vitrifiable mixture.

[0048] Preferably, in the system or process according to the invention, the adjustment of the water content includes the hydration or drying of the premix.

[0049] Preferably, in the system or process according to the invention, the adjustment of the organic compound content includes the calcination of the premix.

[0050] Advantageous embodiments are described below. Examples:

[0051] Fig. 1 is a schematic representation of a system according to the invention, implementing the process of preparing a verifiable mixture according to the invention.

[0052] Fig. 2 is a schematic cross-sectional representation of an online measuring unit (1006) which can be used according to the invention.

[0053] Fig. 3 is a schematic representation illustrating various embodiments for adjusting the premix of raw materials to achieve the target composition of the vitrifiable mixture.

[0054] Referring to Fig. 1, the inline system (1000) for preparing a vitrifiable mixture of target composition is located upstream of a melting furnace (3000) and can be used for manufacturing a mineral glass product (10), for example, flat glass. The vitrifiable mixture of target composition is prepared continuously from a premix (1005) which includes cullet, preferably mixed with other raw materials. Once the vitrifiable mixture of raw materials is formed and ready for loading, it is conveyed to the melting chamber of the furnace (3000), for example, by a conveyor belt (1004). The furnace is continuously fed with a constant quantity of material. This quantity depends, in particular, on the conveyor speed, the conveyor load (volume of material per section conveyed), and the density of the raw materials introduced onto the conveyor.The vitrifiable mixture of raw materials, prepared and continuously conveyed, is then melted to form a bath of fluid glass from which various glass products can be manufactured, such as, for example, flat glass for building and / or automotive glazing, hollow glass for bottles and / or glassware, master glass for ceramic glass plates, or even glass fibers for insulation products.

[0055] The online preparation system (1000) includes a distribution unit (1002) for raw materials intended to be used in the composition of the premix (1005).

[0056] The dispensing unit (1002) may include one or more storage silos (1002a-d) containing different types of raw materials, including cullet. The dispensing unit (1002) is used to prepare a premix (1005), preferably of at least two raw materials. The raw materials, including the cullet, carry chemical elements such as metals, metalloids, alkali metals, and alkaline earth metals, and are combined in relative proportions to form a A verifiable mixture of predetermined target composition, the melting of which yields a mineral glass with the desired properties. Besides cullet, examples of raw materials include mining raw materials (sand, limestone, etc.), alkali and / or alkaline earth carbonates, silicates, aluminosilicates, or oxides or hydroxides of metals, metalloids, alkali and / or alkaline earths. The dispensing unit (1002) may also include a mixer downstream of the silos (not shown) for mixing the raw materials. In the context of the present invention, the dispensing unit is preferably configured to deliver a premix comprising at least 20% by mass of cullet, relative to the mass of the premix.

[0057] The premix (1005) is then transported by one or more conveyors (1004).

[0058] The preparation system (1000) also includes a unit (1006) for non-destructive, non-contact, online, and real-time measurement of the chemical composition of the premix (1005). This allows for continuous verification and, if necessary, adjustment of the premix composition before it enters the furnace's melting chamber. The premix composition may, for example, be prepared based on the desired target composition for the verifiable mixture, but may be quite approximate due to its high cullet content. The unit (1006) advantageously allows for the continuous measurement of both the elemental chemical composition of the premix (1005) and its water content.The preparation system (1000) then allows the mixing of raw materials and / or the parameters of the furnace to be regulated according to the variations in composition and / or humidity observed in the premix, and to prevent quality problems of the glass products (10) of the production line.

[0059] With reference to Fig. 1 and Fig. 2, the online unit of measurement (1006) comprises: - at least one source (2001) of pulsed thermal and fast neutron emission, said source being arranged and configured so as to irradiate all or part of the premix (1005); - at least one gamma ray detector (2002) configured to detect gamma rays emitted by the premix (1005) when irradiated by the neutron emission source (2001); and - a device (1007) for digitally processing the signal from the ray detector gamma, said device (1007) being configured to calculate, from said signal, the content of chemical elements present in the premix (1005). The device (1007) can be more specifically configured to calculate, from the gamma ray detector signal, the content of chemical elements with atomic numbers greater than or equal to 11 constituents of the premix. This makes it possible, in particular, to control the chemical elemental composition of the vitrifiable mixture used and the properties of the resulting glass product. The device (1007) can also be configured to estimate the water content and / or the content of organic compounds in the premix, for example, from the calculated content of chemical elements selected from hydrogen, carbon, nitrogen, and oxygen.

[0060] The measuring unit (1006) can be fixed. When it is fixed, the neutron source(s) (2001) and the gamma ray detector(s) (2002) can be assembled in the form of a fixed gantry with an opening into which the conveyor (1004) can be inserted, as illustrated in Fig. 1. Such an assembly is described, for example, in WO 2006 / 092011 Al or CN 101603929 A.

[0061] According to another advantageous embodiment, the measuring unit (1006) can be mobile. In particular, the neutron source (2001) and the gamma ray detector (2002) can be integrated into a gantry having a C-shaped cross-section. The gantry can be provided with a central opening that opens laterally and is equipped at its base with means for movement, such as, for example, casters. The central and lateral openings are advantageously sized to receive the conveyor (1004) through the lateral opening when the gantry is placed on the conveyor (1004). The advantage of a mobile system is the possibility of moving it along the conveyor or onto another conveyor (1004). Its maintenance is also facilitated by the ease with which it can be removed from the conveyor.

[0062] In the system or method according to the invention, the digital processing (1007) allows the calculation of the chemical element content of the premix (in particular the content of chemical elements with an atomic number greater than or equal to 11). This calculation is performed from the frequency or wavelength spectrum of gamma rays detected by the detector(s). This calculation can notably be performed using standard samples. The estimation of the water content and / or the organic compound content can be carried out from a calculated content of a chemical element among hydrogen, carbon, nitrogen, and / or oxygen. The contents of these elements can be calculated in the same way as that used for chemical elements with atomic number greater than or equal to 11.

[0063] In the system or method according to the invention, the gamma ray detector (2002) has an energy resolution less than or equal to 4.0%.

[0064] According to some embodiments, the measuring unit (1006) may further comprise at least one neutron detector (2002n) arranged and configured to detect all or part of the neutrons emitted by the neutron emission source and transmitted through the premix (1005) by the neutron emission source (2001). In this case, the digital processing device (1007) may also be configured for processing the signal from the neutron detector (2002n), calculating the variations in the kinetic energies of said neutrons passing through the premix, and calculating the moisture content of the premix as a function of said variations in kinetic energy.

[0065] It has been observed that hydrogen from the moisture content of the premix (1005), and particularly from the calcine, slows the propagation of neutrons passing through said premix (1005), resulting in a decrease in the kinetic energy of the neutrons transmitted through the premix. The variations in neutron kinetic energy between the time of their emission and their detection by the neutron detector(s) can be correlated with the amount of hydrogen in the vitrifiable mixture and therefore with its moisture content. This correlation can be modeled by means of a calibration using standard samples representative of a premix containing calcine and / or representative of a vitrifiable mixture.

[0066] The neutron source(s) (2001) and gamma ray detector(s) (2002) can be arranged in different geometric configurations so as to irradiate the premix (1005) moving on the conveyor (1004) and to detect the gamma rays generated by the irradiation.

[0067] According to some embodiments, the neutron emission source (2001) is disposed above the conveyor, and the gamma ray detector (2002) is located below the premix.

[0068] According to some preferred embodiments, the neutron emission source (2001) is disposed below the conveyor, and the gamma ray detector (2002) is located above the premix (as illustrated for example in Figure 2).

[0069] According to other embodiments, the neutron emission source (2001) and the gamma ray detector (2002) are arranged substantially laterally on either side of the conveyor.

[0070] Advantageously, the measuring unit (1006) is pre-calibrated, taking into account the conveyor used during the neutron activation measurement. This allows the measuring unit to account for the materials and composition of the conveyor, which is also subjected to irradiation by the neutron emission source.

[0071] In some embodiments, the system (1000) for preparing a verifiable mixture may further include a control unit (not shown) configured to compare the calculated chemical and / or moisture contents with predefined values. The control unit may, for example, be connected to the measuring unit (1006) to collect the data calculated by the measuring unit, or it may be integrated into the measuring unit (1006), for example, as an integrated module. The control unit, or the step of comparing the calculated chemical contents with predefined values, enables the detection of variations in the composition and / or moisture content of the mixture.This allows, for example, the detection of foreign body debris, particularly from the calcine contained in the premix, as the detected variations may indicate a contaminant present in the premix. Alternatively, or simultaneously, this also allows for adjustments to the proportions of raw materials introduced into the premix, the moisture content of the mixture, and / or the furnace parameters to compensate for the detected variations.

[0072] According to some embodiments, the system (1000) for preparing a verifiable mixture may further include a calculation unit (not shown) configured to determine the adjustment(s) to be made to the premix, in particular to obtain the vitrifiable mixture of target composition. For example, the calculation unit may be configured to calculate the proportions of raw materials to be introduced into the premix to readjust the composition of the mixture. The calculation unit may, for example, be connected to the control unit to determine the adjustments to be made based on the deviations calculated by the control unit, or it may be integrated into the control unit. It may also be connected to a control unit to order adjustments to be made to the premix or it can be integrated into the control unit.

[0073] The predefined values ​​used for comparison, calculation, and / or determining the adjustments to be made can be of any suitable type. They can be representative of the expected composition of the glass mixture for manufacturing a glass product with a desired chemical composition and / or representative of the chemical compositions of foreign bodies stored as a database in the digital processing device.

[0074] In some embodiments, the system (1000) for preparing a vitrifiable mixture may further include a control unit (not shown) configured to control at least one means of adjusting the premix. For example, the control unit may be configured to control the device(s) for dispensing raw materials to be introduced into the premix to readjust the composition of the mixture or to control the diversion of the premix, for example, to premix processing units. The control unit may, for example, be connected to the measuring unit, the control unit, and / or the calculation unit, or it may be integrated into one of these units.

[0075] Advantageously, the system (1000) for preparing a vitrifiable mixture includes at least one means for adjusting the premix to obtain the vitrifiable mixture of target composition. The adjustment means allow the premix to be adjusted to approximate the target composition of the vitrifiable mixture.

[0076] At least one adjustment method may be chosen from among the methods for adjusting the content of chemical elements and / or the methods for adjusting the water content and / or the methods for adjusting the content of organic compounds.

[0077] Fig. 3 illustrates in (A) different means of adjusting the chemical element content. Advantageously, the adjustment of the chemical element content is achieved by modifying the proportions of the raw materials entering the composition of the vitrifiable mixture, in particular after comparing the calculated and target contents.

[0078] According to one embodiment, adjusting the chemical element content includes adding raw materials to the premix, for example upstream or in downstream of the online measuring unit (1006). The addition of raw materials can be carried out for example using the distribution unit (1002a, 1002b, 1002c, 1002d) or using a second raw material distribution unit (1002e, 1002f, 1002g, 1002h), for example downstream of the online measuring unit (1006) of the premix composition.

[0079] In another embodiment, adjusting the chemical element content involves modifying the feed rates of the raw materials in the distribution unit (1002a, 1002b, 1002c, 1002d). In this way, the feed rate of some raw materials can be decreased while the feed rate of others is increased, thereby altering the proportions of raw materials supplied to subsequent premix fractions and compensating overall for the concentration discrepancy observed after measuring the preceding premix fractions.

[0080] In another embodiment, adjusting the chemical content involves recirculating the measured composition premix back to the dispensing unit (1002a, 1002b, 1002c, 1002d). In this way, the measured composition premix is ​​diluted with at least one raw material added via the dispensing unit (1002a, 1002b, 1002c, 1002d), thus forming a new mixture (1005). This new mixture advantageously has a composition closer to that of the target composition of the verifiable mixture. Furthermore, this new premix can be returned to the measuring unit (1006) to check the adjusted composition.

[0081] The adjustment (A) of the chemical element content can be carried out, preferably online, according to one or more of the embodiments described above. The adjustment of the chemical element content may optionally include the addition of cullet, in particular "internal" cullet of known composition, and possibly the addition of pure oxides.

[0082] Adjusting the premix's moisture content involves either hydrating or drying it. In some cases, it may be beneficial to reduce the premix's moisture content, as excessive moisture can negatively impact furnace parameters. Conversely, increasing the premix's moisture content can be advantageous to minimize dust generated by the raw materials (which can infiltrate internal or external furnace components, leading to malfunctions or reduced performance). The adjustment of the water content can be ordered based on the results of the premix water content analysis (estimated by the online measurement unit). The estimated water content of the premix can, for example, be compared to at least one predefined threshold value (e.g., a limit value or a range of acceptable values), and possibly adjusted according to the deviation from this / these threshold value(s). Preferably, the water content is adjusted to a content of 0% to 5%, preferably 1% to 5%, by mass of water relative to the (dry) mass of the vitrifiable mixture.

[0083] In one embodiment, the adjustment of the moisture content can be achieved by conveying the premix to hydration or drying means. Hydration means include, for example, humid ventilated air. Drying means include, for example, dry ventilated air, heating means (e.g., flames), electric heating elements, microwave devices, and lasers.

[0084] According to another embodiment, the water content can be adjusted by diverting at least a portion of the premix to a storage area. The water content of the premix can, for example, be regulated by the relative humidity of the atmosphere in the storage area or by a hydration or drying method, as previously mentioned. In the case of diversion to a storage area, the premix can then be reintroduced, after a specified period, onto the conveyor of the system according to the invention, for example, upstream or downstream of the neutron activation analysis device.

[0085] The adjustment of the organic compound content can be ordered based on the results of the estimated organic compound content of the premix (estimated content using the online measurement unit). The estimated organic compound content of the premix can, for example, be compared to at least one predefined threshold value (e.g., a limit value or a range of acceptable values). These threshold values ​​may depend on the expected end product and the intended application.

[0086] According to one embodiment, the adjustment of the organic compound content of the premix can be carried out by conveying the premix to calcination means, such as a rotary flame kiln or an electric kiln.

[0087] According to another embodiment, adjusting the organic compound content of the premix includes deviating at least a portion of the premixing, for example, to a sorting or cleaning area. This allows for the removal of any contaminants from the premix. The premix can then be reintroduced onto the conveyor, for example, upstream or downstream of the measuring unit (1006) by neutron activation.

[0088] Adjusting the water content and / or the organic compound content of the premix can be done in-line, either directly (i.e., during the conveying of the premix to the furnace) or indirectly, for example, by recirculating the premix to suitable processing means (hydration, drying, and / or calcination means). In-line adjustment by recirculating the premix to suitable processing means (T) is illustrated, for example, in Figure 3 (in-line adjustment B).

[0089] Alternatively, the adjustment of the premix's water content and / or organic compound content can be carried out offline, for example, at a later date. For instance, at least a portion of the premix can be diverted from the continuous furnace feed circuit for storage or conditioning in an environment (e.g., to adjust the water content according to the ambient relative humidity, as previously discussed) or for a processing or cleaning step. The diverted portion of the premix can then be reintroduced into the furnace feed circuit after a certain delay (e.g., into the dispensing unit, after cleaning or conditioning) or repurposed for the manufacture of another glass product with a more suitable composition. Offline fitting is illustrated for example in figure 3 (offline fitting C).

[0090] Preferably, the premix adjustment is performed online. This may include online adjustment of the chemical element content and / or online adjustment of the water content. The premix adjustment may also include online adjustment of the organic compound content.

[0091] The system (1000) according to the invention allows in particular the implementation of the process of preparing a vitrifiable mixture according to the invention.

[0092] All the embodiments set forth in the detailed description of the system according to the first aspect of the invention are directly applicable to the method according to the second aspect of the invention.

[0038] The system (1000) according to the first aspect of the invention and the method according to the second aspect of the invention can be advantageously used in a manufacturing process for a glass product (10).

Claims

Demands 1. Online preparation system (1000) for a verifiable mixture of target composition, in particular for the manufacture of flat glass, the system comprising: - a raw materials distribution unit (1002a, 1002b, 1002c, 1002d) capable of supplying a premix (1005) comprising cullet, preferably at least 20% by mass of cullet; - a conveyor (1004) capable of setting the premix (1005) in motion; - an online unit of measurement (1006) of the composition of the premix by neutron activation, said online unit of measurement comprising: • at least one source (2001) of pulsed thermal and fast neutron emission, said source being arranged and configured so as to irradiate all or part of said premix (1005); • at least one gamma ray detector (2002) configured to detect gamma rays emitted by the premix (1005) when irradiated by the neutron emission source (2001); and • a digital processing device (1007) configured to calculate, from the gamma ray detector signal, the chemical element content present in the premix (1005), and optionally configured to estimate the water content and / or the organic compound content in the premix; and - at least one means of adjusting the premix to obtain the verifiable mixture of target composition.

2. Online preparation system (1000) according to claim 1, wherein the premix comprises at least two different raw materials.

3. Online preparation system (1000) according to any one of the preceding claims, wherein the premix represents at least 50% by mass, preferably at least 70% by mass, more preferably at least 90% by mass of the verifiable mixture of target composition.

4. Online preparation system (1000) according to any one of the preceding claims, wherein the gamma ray detector (2002) has an energy resolution less than or equal to 4.0%.

5. Online preparation system (1000) according to any one of the preceding claims, wherein the measuring unit (1006) further comprises at least one neutron detector (2002n) disposed and configured to detect all or part of the neutrons emitted by the neutron emission source (2001) and transmitted through the premix (1005), and the digital processing device (1007) is configured to calculate, from the signal of said neutron detector (2002n), variations in the kinetic energies of said neutrons passing through the premix and to calculate a water content of the premix (1005) as a function of the variations in kinetic energies.

6. Online preparation system (1000) according to any one of the preceding claims, further comprising a control unit configured to compare the calculated chemical element contents of the premix with the contents of the target composition of the vitrifiable mixture.

7. Online preparation system (1000) according to claim 4, wherein the control unit is configured to compare the water content of the premix with at least one predefined value.

8. Online preparation system (1000) according to any one of the preceding claims, the preparation system being arranged upstream of a glass furnace and further comprising a control unit configured to adapt online at least one furnace parameter, according to the calculated chemical element contents of the premix and / or the water content of the premix.

9. Online preparation system (1000) according to any one of the preceding claims, wherein at least one adjustment means is selected from means for adjusting the content of chemical elements and / or means for adjusting the water content and / or means for adjusting the content of organic compounds.

10. A process for the online preparation of a vitrifiable mixture of target composition, in particular for the manufacture of flat glass, the process comprising: - the supply of a premix (1005) comprising cullet, preferably at least 20% by mass of cullet; Tl - the conveying of the premix (1005); - online measurement of the premix composition by neutron activation, said online measurement comprising: • irradiation of all or part of the premix by at least one (2001) pulsed thermal and fast neutron emission source; • the detection of gamma rays emitted by the irradiated premix; and • digital processing of the gamma ray detection signal to calculate the chemical element content present in the premix (1005), and possibly to estimate the water content and / or the organic compound content in the premix; and - adjusting the premix (1005) to obtain the vitrifiable mixture of target composition.

11. Online preparation method according to claim 10, wherein the premix (1005) comprises at least two different raw materials.

12. Online preparation method according to any one of claims 10 or 11, wherein the premix represents at least 50% by mass, preferably at least 70% by mass, more preferably at least 90% by mass of the vitrifiable mixture of target composition.

13. Online preparation method according to any one of claims 10 to 12, wherein gamma ray detection is carried out using a gamma ray detector (2002) having an energy resolution less than or equal to 4.0%.

14. An online preparation method according to any one of claims 10 to 13, wherein the online measurement step further comprises: • the detection of all or part of the neutrons emitted by the neutron emission source (2001) and transmitted through the premix (1005); • the digital processing of the neutron detection signal in order to calculate the variations in the kinetic energies of the neutrons transmitted through the premix and to calculate the water content of the premix (1005) as a function of the variations in kinetic energies.

15. Online preparation method according to any one of claims 10 to 14, further comprising, after the online measurement step of the premix composition, the comparison of the calculated chemical element contents of the premix with the contents of the verifiable target composition of the mixture, and optionally, the comparison of the water content of the premix with at least one predefined value.

16. Online preparation method according to any one of claims 10 to 15, further comprising an online adaptation step of the parameters of a glass furnace continuously fed with the vitrifiable mixture of target composition, according to the calculated chemical element contents of the premix and / or the water content of the premix.

17. Online preparation method according to any one of claims 10 to 16, wherein the premix adjustment step includes adjusting the chemical content and / or adjusting the water content and / or adjusting the organic compound content.

18. A method for manufacturing a glass product comprising the preparation of a vitrifiable mixture according to the method as defined in any one of claims 10 to 17, or using the system as defined in any one of claims 1 to 9.

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