Process and system for preparing a vitrifiable mixture.

Abstract

According to a first aspect, the invention relates to an online preparation system for a vitrifiable mixture of target composition, the system comprising: - a raw material distribution unit capable of supplying a premix comprising cullet, preferably at least 20% by mass of cullet; - a conveyor capable of moving the premix; - an online measurement unit for the composition of the premix by neutron activation, the online 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 gamma ray detector signal, the chemical element content present 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 for adjusting the premix to obtain the vitrifiable mixture of target composition. The invention also relates to a method for preparing a vitrifiable mixture of target composition online. Figure 1.

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 the 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, called "cullet" in English, is made from glass waste and is used as a substitute for some of the usual mining raw materials in order to reduce the environmental impact of the glass industry. Indeed, the use of recycled mineral glass reduces 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. Furthermore, cullet may contain a greater or lesser quantity of contaminants, such as residues of organic and / or inorganic layers on the surface of certain glass fragments, or various debris of foreign bodies (such as ceramics, earthenware, porcelain, terracotta, plastic, metals, electronic components, etc.). Thus, there is a wide variety of cullet, of varying qualities, depending on its origin or its processing methods (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 mixture. However, this type of cullet is often less readily available than "external" cullet if the aim is to increase the proportion of cullet in glass mixtures. On the other hand, "external" cullet has a much more variable composition and is used on a limited scale in the raw material mixture and 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 that meets the defined production specifications, resulting in both production losses and raw material waste.

[0006] Furthermore, depending on their origin, processing methods, and / or storage conditions, different cullets or batches of cullet may also contain highly variable moisture content, which can also disrupt the melting process. Indeed, these variations can have a significant impact on the proper melting and "digestion" of the raw materials in the furnace, on increasing the energy required, and on premature furnace wear. If the melting parameters are not controlled, excessively high moisture content can lead to incomplete melting of the cullet and / or other raw materials in the furnace, resulting in a non-compliant or low-quality finished product.

[0007] To meet the challenges of reducing environmental impacts, it is necessary to use increasingly larger proportions of cullet in mixtures of vitrifiable raw materials, for example, greater than 30% by mass, or even greater than 50% by mass or greater than 70% by mass. However, such proportions require the use of larger shares of external cullet, the variability of whose composition and batches continues to disrupt the melting process and leads to the discarding of a significant quantity of finished products, which constitutes a waste of resources and energy.

[0008] There is therefore always a need to produce target glass compositions from large quantities of cullet while ensuring both the preservation of quality and the conformity of finished products and to limit as much as possible the number of rejections related to the variability of batches of raw materials.

[0009] It is to the applicant's credit that they have proposed a process and system for preparing a vitrifiable mixture of target composition which, surprisingly, makes it possible to solve these problems. Summary of the invention

[0010] According to a first aspect, the invention relates to an online preparation system for a vitrifiable mixture of target composition, 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 to obtain the vitrifiable mixture of target composition.

[0011] According to a second aspect, the invention relates to a method for the online preparation of a vitrifiable mixture of target composition, 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 content of chemical elements present in the premix, and possibly in order to estimate the water content and / or the organic compound content in the premix; and - adjusting the premix to obtain the vitrifiable mixture with the target composition.

[0012] The invention allows for the precise analysis and real-time, online adjustment of the composition of the raw material mixture, including a significant proportion of cullet, 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 constant 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 products.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).

[0013] 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

[0014] The system and method according to the invention include the supply of a premix comprising calcine, preferably at least 20% by mass of calcine.

[0015] 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.

[0016] 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 mining product. Even more preferably, the premix may comprise at least one external cullet and at least one other raw material, in particular a mining product.

[0017] For the purposes of the present 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, in particular "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 silico type.

[0018] The premix may have a different chemical composition and / or water content than that of the target composition vitrifiable mixture. Online preparation system

[0019] 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 vitrifiable mixture of target composition.

[0020] 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.).

[0021] The inline measuring unit may be located downstream of the distribution 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 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, in particular the content of chemical elements with an atomic number greater than or equal to 11.

[0022] The neutron emission source(s) is / are advantageously a pulsed thermal and fast neutron emission source. The neutron emission source(s) may be of any suitable type. It may 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

[0023] The gamma ray detector(s) may be of any suitable type. It may be a gas ionization detector, a scintillation detector, for example one of those described in WO 00 / 03237 A1, or a semiconductor photodetector such as, for example, a germanium detector or a detector made of a photoreactive material. Preferably, at least one gamma ray detector comprises a bismuth germanate material (Bi4Ge30i2 or "BGO").

[0024] Advantageously, the digital processing device can also be configured to estimate the water content and / or the organic compound content in the premix.

[0025] 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.

[0026] 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 target composition of the vitrifiable 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.

[0027] 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 to approximate predefined values ​​for chemical elements and / or moisture content. 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 vitrifiable mixture intended for the melting furnace, particularly based on the measured contents and the deviations observed when comparing them with predefined values ​​(target contents or predefined threshold values). The calculation unit may, for example, be connected to the measuring unit and / or the control unit, for example to collect the data calculated by the measuring unit and / or the deviations calculated by the control unit, or it may be integrated into the control unit.The calculation unit can optionally be connected to a control unit to order the adjustments to be made to the premix, or it can be integrated into a control unit.

[0028] 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.

[0029] 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 levels calculated by the inline measuring unit. This can be the same control unit that controls the premix adjustment means defined above or a separate control unit. Preferably, this control unit is also configured to control the premix adjustment means.

[0030] 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, in particular based on the calculated chemical element contents and / or the water contents estimated by the online measuring unit, for example, from a signal from the measuring unit, the control unit, or the calculation unit. The control unit can, for example, be connected to the measuring unit, the control unit, and / or the calculation unit. Alternatively, the control unit can be integrated with the control unit and / or the calculation unit of the preparation system according to the invention.

[0031] The premix adjustment means allow the premix to be adjusted according to the results of the online measuring unit and the target composition vitrifiable mixture, in particular, to reduce the gap between the results of the online measuring unit and the target composition vitrifiable mixture.

[0032] 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

[0033] 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 - adjustment of the premix to obtain the vitrifiable mixture of target composition.

[0034] The online preparation process according to the invention may further include, after the adjustment step, the online 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.).

[0035] The online measurement of the premix composition can be carried out using the online measuring unit as described above. 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.

[0036] Preferably, the digital processing of the detected signal also allows estimation of the water content and / or the content of organic compounds in the premix.

[0037] More specifically, the online measurement step may further 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.

[0038] 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 calculated levels and 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 acceptable threshold values ​​for chemical elements and / or water).

[0039] 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 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, particularly based on the measured contents and the deviations observed when comparing them with predefined values ​​(target contents or predefined threshold values).

[0040] 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 vitrifiable mixture of target composition. This adjustment step may include adjusting the furnace temperature, particularly based on the calculated chemical element concentrations and / or the water content estimated by the online measuring unit, for example, following a comparison with predefined values.

[0041] 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.

[0042] 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.

[0043] Preferably, in the system or process according to the invention, the adjustment of the water content includes the hydration or drying of the premix.

[0044] Preferably, in the system or process according to the invention, the adjustment of the organic compound content includes calcining the premix.

[0045] Advantageous embodiments are described below. Examples

[0046] Fig. 1 is a schematic representation of a system according to the invention, implementing the process of preparing a vitrifiable mixture according to the invention.

[0047] The [Fig.2] is a schematic cross-sectional representation of an online measuring unit (1006) which can be used according to the invention.

[0048] 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.

[0049] With reference to [Fig. 1], the inline system (1000) for preparing a vitrifiable mixture of target composition is arranged 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 regular quantity of material. This quantity depends, in particular, on the conveyor speed, the conveyor load (volume of material per conveyed section), 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 hobs, or even glass fibers for insulation products.

[0050] The online preparation system (1000) includes a distribution unit (1002) for raw materials intended to be included in the composition of the premix (1005).

[0051] 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 cullet, carry chemical elements such as metals, metalloids, alkalis, and alkaline earths, and are combined in relative proportions to form a vitrifiable 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, alkalis, and / or alkaline earths. The distribution 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 distribution unit is preferably configured to deliver a premix comprising at least 20% by mass of cullet, relative to the mass of the premix.

[0052] The premix (1005) is then transported by one or more conveyors (1004).

[0053] 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 the mixture enters the furnace's melting chamber. The premix composition may, for example, be prepared based on the desired target composition for the vitrifiable mixture, but may be quite approximate due to its high cullet content. The unit (1006) advantageously allows for continuous measurement of both the elemental chemical composition of the premix (1005) and its water content.The preparation system (1000) then makes it possible to regulate the mixing of raw materials and / or the furnace parameters according to the variations in composition and / or humidity observed in the premix, and to prevent quality problems in the glass products (10) of the production line.

[0054] With reference to [Fig.1] and [Fig.2], the online measuring unit (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 digital signal processing device (1007) for the gamma ray detector, said device (1007) being configured to calculate, from said signal, the chemical element content 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 organic compound content in the premix, for example from the calculated content of chemical elements chosen from hydrogen, carbon, nitrogen and oxygen.

[0055] The measuring unit (1006) can be fixed. When 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 A1 or CN 101603929 A.

[0056] 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.

[0057] In the system or method according to the invention, the digital processing (1007) makes it possible to calculate 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 an atomic number greater than or equal to 11.

[0058] According to certain 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.

[0059] It has been observed that hydrogen from the moisture in the premix (1005), and particularly from the calcine, slows down 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 kinetic energy of the neutrons 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 cullet and / or representative of a vitrifiable mixture.

[0060] The neutron source(s) (2001) and the 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.

[0061] 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.

[0062] 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 [Fig.2]).

[0063] 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.

[0064] 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 take into account the materials and composition of the conveyor, which is also subjected to irradiation by the neutron emission source.

[0065] According to certain embodiments, the system (1000) for preparing a vitrifiable mixture may further include a control unit (not shown) configured to compare the calculated chemical and / or moisture content 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, in the form of an integrated module. The control unit, or the step of comparing the calculated chemical content with predefined values, makes it possible to detect 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; the detected variations may be indicative of a contaminant present in the premix. Alternatively, or simultaneously, this also allows for readjusting the proportions of raw materials to be introduced into the premix. to readjust the moisture content of the mixture and / or adjust the oven parameters in order to compensate for the detected variations.

[0066] According to certain embodiments, the system (1000) for preparing a vitrifiable 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 command unit to order the adjustments to be made to the premix, or it may be integrated into the control unit.

[0067] The predefined values ​​used for comparison, calculation, and / or determination of adjustments to be made can be of any suitable type. They can be representative of the expected composition of the vitrifiable mixture for manufacturing a glass product of desired chemical composition and / or representative of chemical compositions of foreign bodies stored as a database in the digital processing device.

[0068] According to certain 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.

[0069] 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.

[0070] At least one adjustment means may be chosen from among the means for adjusting the content of chemical elements and / or the means for adjusting the water content and / or the means for adjusting the content of organic compounds.

[0071] Figure 3 illustrates in (A) different means of adjusting the chemical element content. Advantageously, adjusting the chemical element content is achieved by modifying the proportions of the raw materials used in the composition. of the vitrifiable mixture, particularly after comparison of the calculated contents and the target contents.

[0072] According to one embodiment, adjusting the chemical element content includes adding raw materials to the premix, for example upstream or downstream of the inline measuring unit (1006). The addition of raw materials can, for example, be carried out using the dispensing unit (1002a, 1002b, 1002c, 1002d) or using a second raw material dispensing unit (1002e, 1002f, 1002g, 1002h), for example downstream of the inline measuring unit (1006) of the premix composition.

[0073] According to another embodiment, adjusting the chemical element content involves modifying the raw material flow rates of the distribution unit (1002a, 1002b, 1002c, 1002d). In this way, the flow rate of some raw materials can be decreased while the flow rate of others is increased, thereby altering the proportions of raw materials supplied to the subsequent premix fractions, and making it possible to compensate overall for the difference in content observed following the measurement of the preceding premix fractions.

[0074] According to another embodiment, adjusting the chemical content includes recirculating the premix of measured composition back to the dispensing unit (1002a, 1002b, 1002c, 1002d). In this way, the premix of measured composition 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 vitrifiable mixture. Furthermore, this new premix can be returned to the dispensing unit (1006) to check the adjusted composition.

[0075] 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 calcine, in particular "internal" calcine of known composition, and possibly the addition of pure oxides.

[0076] Adjusting the premix's water content involves hydrating or drying the premix. In some cases, it may be advantageous to decrease the premix's water content, as excessive moisture can affect furnace parameters. In other cases, increasing the premix's moisture content may be useful to limit dust generated by the raw materials (which can enter the internal or external parts of the furnaces, causing malfunctions or degrading their performance). Adjusting the water content can be ordered based on the results of the water content of the Premix (content estimated by the online measuring 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.

[0077] According to one embodiment, the adjustment of the water 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, for example by flames, electric resistances, microwave devices, lasers.

[0078] According to another embodiment, the adjustment of the water content can be carried out 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 a diversion to a storage area, the premix can then be reintroduced, after a given period, onto the conveyor of the system according to the invention, for example, upstream or downstream of the neutron activation analysis device.

[0079] The adjustment of the organic compound content can be ordered based on the results of the estimated organic compound content of the premix (content estimated by the online measuring 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.

[0080] 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 for example a rotary flame kiln or an electric kiln.

[0081] According to another embodiment, adjusting the organic compound content of the premix involves diverting at least a portion of the premix, for example, to a sorting or cleaning area. This allows for the removal of any contaminants from the premix. The premix can then optionally be reintroduced onto the conveyor, for example, upstream or downstream of the measuring unit (1006) by neutron activation.

[0082] The adjustment of the water content and / or the adjustment of the organic compound content of the premix can be carried out inline, either directly (i.e., during the conveying of the premix to the furnace) or indirectly, for example with recirculation of the premix to appropriate processing means (premix hydration, drying and / or calcination means). Online adjustment by recirculation of the premix to appropriate processing means (T) is illustrated, for example, in [Fig. 3] (online adjustment B).

[0083] Alternatively, the adjustment of the water content and / or the adjustment of the organic compound content of the premix can be carried out offline, for example, on a delayed basis. For example, at least a portion of the premix can be diverted from the continuous furnace feed circuit for storage or conditioning in an environment (for example, to adjust the water content according to the ambient relative humidity, as seen previously) or to undergo a processing or cleaning step. The diverted portion of the premix can optionally be reintroduced after a certain delay into the furnace feed circuit (for example, into the dispensing unit, after cleaning or conditioning) or be reassigned for the manufacture of another glass product with a more suitable composition. Offline adjustment is illustrated, for example, in [Fig. 3] (offline adjustment C).

[0084] Preferably, the premix adjustment is carried out online. It may include online adjustment of the chemical element content and / or online adjustment of the water content. The premix adjustment may further include online adjustment of the organic compound content.

[0085] The system (1000) according to the invention allows in particular the implementation of the process of preparing a vitrifiable mixture according to the invention.

[0086] 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.

[0087] 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 vitrifiable mixture of target composition, the system comprising: - a raw material 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 measurement unit (1006) for the composition of the premix by neutron activation, said online measurement unit comprising: • at least one pulsed thermal and fast neutron emission source (2001), 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 signal of the gamma ray detector, the content of chemical elements present in the premix (1005), and optionally configured to estimate the water content and / or the content of organic compounds in the premix; and - at least one means of adjusting the premix to obtain the vitrifiable mixture of target composition.

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

3. An 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 content in water of the premix (1005) as a function of the variations in kinetic energies.

4. 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.

5. 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.

6. 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.

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

8. A method for preparing a vitrifiable mixture of target composition in line with an online method, the method comprising: - supplying a premix (1005) comprising cullet, preferably at least 20% by mass of cullet; - conveying the premix (1005); - measuring the composition of the premix in line with an online method by neutron activation, said online measurement comprising: • irradiating all or part of the premix by at least one source of pulsed thermal and fast neutrons; • detecting the gamma rays emitted by the irradiated premix; and • digitally processing the gamma ray detection signal so as to calculate the content of chemical elements present in the premix, and optionally so as to estimate the water content and / or the content of organic compounds in the premix; and - adjusting the premix to obtain the vitrifiable mixture of target composition.

9. An online preparation method according to claim 8, wherein the premix comprises at least two different raw materials.

10. An online preparation method according to any one of claims 8 or 9, 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 so as 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.

11. An online preparation method according to any one of claims 8 to 10, 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 target composition of the vitrifiable mixture, and optionally, the comparison of the water content of the premix with at least one predefined value.

12. An online preparation method according to any one of claims 8 to 11, further comprising an online adaptation step of the parameters of a glass furnace continuously fed with the target composition vitrifiable mixture, according to the calculated chemical element contents of the premix and / or the water content of the premix.

13. An online preparation process according to any one of claims 8 to 12, wherein the premix adjustment step includes adjusting the chemical content and / or adjusting the water content and / or adjusting the organic compound content.

14. 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 8 to 13, or using the system as defined in any one of claims 1 to 7.

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