Method for sorting and recycling refractory moldings, preferably bricks, and methods for their use

Abstract

The present invention relates to a method for sorting and recycling preferably crude ceramic refractory articles (1, 1a, 1b), preferably bricks, and to a method for utilizing the sorted or recycled articles.

Description

[Technical Field]

[0001] The present invention relates to a method for sorting and recycling preferably crude ceramic refractory products, preferably bricks, and to a method for utilizing the sorted or recycled products. [Background technology]

[0002] In the sense of the present invention, the term "refractory" is not limited to the definition according to ISO 836 or DIN 51060, which define a refractoriness above 1500°C. Refractories in the sense of the present invention are those that have a compression softening point T according to DIN EN ISO 1893:2008-09. 0.5 T 0.5 ≥ 600 ° C, preferably T 0.5 Refractory or refractory granular materials or granules in the sense of the present invention therefore have a compression softening point T 0.5 The material is a granular material suitable for refractories having the above structure.

[0003] Refractories are used to protect the aggregate structure of aggregates where temperatures between 600 and 2000 °C, especially 800 and 1800 °C, prevail.

[0004] In particular, they are used as fire-resistant linings for heat treatment plants, preferably melting, calcining, heat treatment plants or transport vessels, but they can also be functional products (see Gerald Routschka / Hartmut Wuthnow, Praxishandbuch “Feuerfeste Werkstoffe”, 6th edition, Vulkan-Verlag (hereinafter also simply referred to as “Practical Handbook”), Chapter 1.6).

[0005] The refractory lining covering the shell of the plant or transport vessel may be single-ply or multi-ply, usually multi-ply. The lining consists of a working or wear casing on the fire side or inside the aggregate, which wears during use and must be replaced periodically. If the wear casing is made of refractory bricks, the fire side in particular will wear during use. However, at least some of the bricks can be reused after use, and for this purpose they are mechanically removed from the wear casing.

[0006] Additionally, the lining may include a wear casing followed by a permanent casing, which then remains in the plant or shipping container and acts as a safety casing during several furnace moves or cycles, and which may also be followed by an insulating lining.

[0007] Coarse ceramic products are known to be products made from granular materials with a grain size of up to 6 mm, and in special cases up to 25 mm (Practical Handbook, Chapter 2). Coarse ceramics are distinguished from fine ceramics by the grain size of their microstructural components: if the microstructural components are at least partially larger than 1 mm, the product is a coarse ceramic product; if the microstructural components are all 1 mm or smaller, the product is a fine ceramic.

[0008] Furthermore, a distinction is made between non-basic (Practical Handbook, 4.1) and basic (Practical Handbook, 4.2) refractories. According to DIN EN ISO 10081:2005-05, a distinction is made between non-basic and basic refractory products, particularly based on their chemical reactivity. The non-basic product group includes materials from the SiO2-Al2O3 series and other materials that cannot be more precisely classified according to their chemical reactivity, such as SiC and carbon products. An important feature of most basic products is that they consist primarily of the sum of the oxides MgO and CaO. Furthermore, chromite, picrochromite, spinel, and forsterite bricks, although nearly neutral, are classified as basic products.

[0009] In the case of raw ceramic products, a distinction is also made between formed and unformed products. Molded crude ceramic products are unfired, possibly tempered, or ceramic fired products, especially bricks or plates, preferably produced in ceramic factories. They have a defined shape and can be placed immediately. Molding is carried out, for example, by pressing, stamping, ramming or slip casting. Molded products, especially bricks, are then walled with mortar or without mortar ("crunching"), for example to form a lining. The manufacturing process for crude ceramic molded products is usually divided into the following steps (Practical Handbook, page 14 / point 2.1): -Preparation Steps -Mixing step -Molding step -Drying step (if necessary) Heat treatment or baking step down to -800°C (if required) -Post-processing steps (if necessary)

[0010] A green product (Practical Handbook, p. 142 / point 5) is a product that is formed into its final shape, usually at the user's site, from a fresh unformed mass or block by, for example, casting, vibrating, extruding, ramming, or spraying. Green products are usually placed behind formwork at the larger site of use and, after hardening, form part of the lining. For example, green products can be shotcrete, rammed, cast, vibrated, or grouted.

[0011] Recycling of refractories is becoming increasingly important for economic and environmental reasons, as well as due to resource scarcity. Reusing recycled materials to produce new refractories offers the advantages of cheaper raw materials compared to primary raw materials, lower processing costs, less energy consumption and a reduced carbon dioxide footprint.

[0012] However, before the crushed products can be reused, they must be sorted by type. This is because different types of products are usually mixed together after the lining is crushed. Depending on the location and time of use, the products may have been subjected to different stresses and may have undergone chemical or mineralogical changes, so not all products are suitable for reuse or for the manufacture of different products. Crushed products may be contaminated, for example, by the penetration or adhesion of slag, molten clinker, metals, salts, or other process media.

[0013] Chemical analysis of crushed products using Laser-Induced Breakdown Spectroscopy (LIBS) to separate them based on their chemical / mineral composition is well known in the field (see, for example, https: / / cordis.europa.eu / article / id / 197342-how-to-turn-refractory-waste-back-into-raw-materials / de). Multi-element analysis allows for classification of the different refractory materials. In particular, it is possible to identify the main components and some aggregates.

[0014] However, this method does not always fully capture the chemical / mineralological properties of refractories. For example, it is not possible to definitively determine whether a refractory contains carbon or not. This is because the surface of the refractory changes during use. Carbon burns off on the fire side of the product. The penetration depth of LIBS measurements is typically limited to a few hundred microns, so carbon may not be detected even if it is present in the product.

[0015] Additionally, it is known in the art to provide sensors or chips in refractories for various purposes.

[0016] For example, International Publication No. 2008 / 135135 discloses ceramic components with integrated sensors for data collection and transmission. The collected information includes the component's identity, physical characteristics, movement, service life, or location. The challenge is to identify and describe the component's condition or operational time before, during, and after use. Information for identifying the component includes, for example, product type, material type, manufacturer details, date of manufacture, delivery date, and date of use. In particular, temperature measurements and measurements of mechanical stress as a function of time can be used to predict the component's wear state and ensure that the component is replaced promptly and without premature wear. However, International Publication No. 2008 / 135135 does not disclose recycling of the component.

[0017] WO 2020 / 254134 discloses the use of sensors (such as RFID chips) in refractory components such as sliding gate valve plates for monitoring and tracking replaceable refractory components in metallurgical plants.

[0018] EP 3119915 discloses a metallurgical vessel equipped with a transponder that can be read wirelessly.

[0019] Patent document 4 (WO 2010 / 057656) discloses a device for actively tracking specific data relating to systems or parts of a metallurgical plant, where at least one writable and readable storage medium for the specific data (e.g., an RFID chip) is permanently connected to each part, and the specific data can be changed periodically and / or in response to input. Such data can include physical, mechanical, and / or chemical properties of the parts. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] International Publication No. 2008 / 135135 [Patent Document 2] International Publication No. 2020 / 254134 [Patent Document 3] European Patent No. 3119915 [Patent Document 4] International Publication No. 2010 / 057656 Summary of the Invention [Problem to be solved by the invention]

[0021] The object of the present invention is to provide a sorting method for sorting preferably aggregates, preferably crude ceramic refractory moldings, preferably bricks, which have been used in a furnace and crushed therefrom after use, ensuring efficient and accurate sorting of the crushed products.

[0022] It is a further object of the present invention to provide a method for recycling crushed moldings and to provide uses for the crushed products. [Means for solving the problem]

[0023] This problem is solved by a sorting method having the features of claim 1, a recycling method having the features of claim 13 and a utilization method having the features of claim 14. Advantageous further embodiments of the invention are characterized in the following dependent claims. [Brief explanation of the drawings]

[0024] The invention will be explained in more detail below with reference to the drawings in which: [Figure 1] FIG. 1 is a schematic diagram of the life cycle of a refractory fired product recycled in accordance with the present invention. [Figure 2] FIG. 2 is a schematic diagram of the life cycle of refractory greenware recycled in accordance with the present invention. [Figure 3] FIG. 3 is a schematic diagram of a cross section of a refractory brick incorporating a transponder. DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a schematic diagram of a life cycle 100 of a refractory sintered article 1 . 1, first, step 101 of processing the raw materials used in the production is carried out in a known manner. These are primary and secondary raw materials. This is followed by step 102 of mixing the processed raw materials and step 104 of shaping, preferably pressing, the mixture to form a shaped green part 1a. Next, step 105 of ceramic firing of the shaped, in particular pressed, green part 1a is carried out in a furnace.

[0026] According to the invention, after baking, the baked product 1 is fitted with at least one transponder 2 (step 106), after which a quality control of the baked product 1 is preferably carried out (step 107).

[0027] The transponder 2 is known to be a wireless communication device that receives an incoming signal and automatically responds or forwards the signal. As is known, the transponder 2 can receive information from or transmit information to a transmitter unit and / or a receiver unit 8 in a contactless process.

[0028] The transponder 2 comprises, in a manner known per se, coupling elements such as an antenna and a microchip. The microchip contains analog circuits for reception and transmission (transceiver), digital circuits, preferably a microcontroller, and a memory. The memory is a memory that can be written to at least once. An unalterable, in particular unique, ID of the transponder 2 is stored in the memory. However, it is preferable for the memory to be rewritable so that information can be saved and / or changed multiple times during the life of the transponder 2.

[0029] The transponder 2 is preferably a passive transponder 2 . As is well known, a passive transponder 2 draws the energy required for communication and running its internal processes solely from the electromagnetic fields of the transmitter and / or receiver unit 8 .

[0030] Preferably, the transponder 2 is also an RFID (Radio Frequency Identification) transponder 2 . Furthermore, the transponder 2 preferably comprises means for measuring the temperature and / or means for measuring the humidity.

[0031] Furthermore, the green and fired products 1, 1a each have a fired or hot side 3a and an opposing cold side 3b. When the product 1 is installed, the hot side 3a faces the fired aggregate interior of the aggregate 5 or a combustion chamber 4, preferably a furnace 6. The cold side 3b faces away from the combustion chamber 4.

[0032] Preferably, the transponder 2 is placed, positioned or fixed in a cutout or recess 7 in the cold part side 3b of the molded part 1. The placement on the cold part side 3b ensures that the temperature load on the transponder 2 during use is as low as possible. The placement of the transponder 2 in the recess 7 also ensures mechanical protection of the transponder 2. In particular, it is guaranteed that the transponder 2 is not damaged during handling during transport of the molded part 1 and during installation and removal of the molded part 1.

[0033] According to the invention, applying product-specific information 108 to the transponder 2 by a transmitting / receiving unit 8 known per se is now performed, whereby information regarding at least the chemical and / or mineral composition of the respective molded part 1 is applied or stored. Preferably, the product-specific information is a recipe. The recipe includes all materials used in the production of the product, i.e., in particular the main and secondary components used, and in particular also additives. Preferably, the recipe also includes information regarding the chemical composition of the materials used, in particular the impurity content, such as iron. In particular, the presence and amount of additives cannot be easily determined using known methods.

[0034] Furthermore, it is desirable to apply or store at least one of the following information: -Manufacturing date -Internal recipe number - information about the manufacturing process, in particular the mixing time and / or pressing pressure and / or firing temperature - Waste code number -Pallet number for tracking

[0035] For example, the production date in combination with the recipe number can be used to identify the materials used in production and their composition if the relevant data is stored in a database, in which case the complete recipe does not need to be stored on the transponder 2.

[0036] Application of the information (step 108) is followed by packaging of the baked goods 1 (step 109) and transportation to the point of use (step 110). After arrival at the place of use, additional information may be applied to the transponder 2 (step 108) and / or the information may be read (step 111). In particular, the information read may be passed on to the plant operator's product management system.

[0037] This is followed by a step 112 of attaching or installing the moldings 1 to the aggregate 5. In particular, a step 113 of refractory lining or cladding the aggregate 5 with the moldings 1 is performed. The moldings 1 are preferably used to manufacture either a wear casing, a permanent casing or an insulating backing. Thus, after installation (step 112), they form part of the lining 9 of the aggregate 5, in particular part of the wear casing, the permanent casing or the insulating backing.

[0038] Before or after installation (step 112), it is preferable to apply further information to the transponder 2 (step 108), in particular information relating to the place of use, in particular the aggregate 5 itself and preferably the area within the aggregate 5, preferably in the furnace 6, and / or the assembly method. With regard to the assembly method, in particular information can be applied as to whether the moulded part 1 is mortared or not.

[0039] The molded article 1 is then used in an aggregate 5, preferably in a furnace 6 (step 114). If a transponder 2 is installed for this purpose, preferably continuous temperature and / or humidity and / or atmosphere measurements are carried out during use, i.e. in the field, by each transponder 2. The transponder 2 also stores the results of these measurements.

[0040] After a period of use, a step 115 is performed in which the moulded articles 1 are crushed or removed from the aggregate 5, preferably from the furnace 6. Preferably, after the crushing step 115, a further application of information to the transponder 2 of the crushed mouldings 1b (step 108) is carried out, in particular information relating to the use of the mouldings 1 (step 114), preferably information relating to the time of use and / or the temperature situation inside the aggregate or in the combustion chamber 4 and / or the atmosphere inside the aggregate or in the combustion chamber 4, in particular the alkali content of the atmosphere and / or the material produced or treated in the aggregate 5, preferably in the furnace 6 and / or the raw materials used for this purpose.

[0041] This is because information about the use of the article 1 also allows predictions to be made about the mineralogical and / or chemical composition of the crushed article 1b when subjected to stresses that change during use.

[0042] Thereafter, a step 116 of sorting the crushed articles 1b is carried out. According to the invention, the step 116 of sorting is carried out inter alia on the basis of the information contained in the transponder 2 relating to the mineralogical and / or chemical composition of the articles 1b. For this purpose, the step 116 of sorting is preceded by a step 111 of reading the information from the transponder 2.

[0043] The read information is processed by a data processing program or system and / or an operator and used for sorting. In particular, during the sorting step 116, the molded articles 1b are sorted into different material classes. Depending on whether the material classes are reusable, the molded articles 1b are returned (step 117) and reused or disposed of according to law (step 118).

[0044] For reuse, the reusable molding 1b is fed back into the manufacturing process of a new, in particular reprocessed, fire-resistant molding 1. The reusable molded article 1b can be used to produce molded articles 1 of the same molded article type, or to produce other fire-resistant molded articles, for example, to produce unmolded fire-resistant products (not shown).

[0045] FIG. 2 shows the life cycle 100a of a green fire-resistant molded article 1a. In contrast to the sintered part 1, instead of the sintering step 105, it is preferable to carry out only the heat treatment step 119 at a maximum temperature of up to 800° C. The green part 1a is then sintered in situ during use (step 114) in a manner known per se.

[0046] In particular, in the case of the unsintered molded article 1a, since it usually undergoes chemical and / or mineral changes during use, information regarding use is advantageous for sorting. Furthermore, according to the invention, fired or unfired moldings 1, 1a that were not used in the aggregate 5 but still need to be recycled can also be sorted out.

[0047] In particular, molded articles 1 and 1a must be recycled if their expiration date has passed or if they have been altered for other reasons during storage or transportation, making them unusable. For example, magnesia bricks may be exposed to high humidity for long periods during storage or transportation, and may become hydrated and unusable.

[0048] This can be determined, for example, by reading the humidity, if the transponder 2 has a means for measuring this. Furthermore, waste generated during the manufacture of the molded articles 1, 1a or resulting from overproduction of the molded articles 1, 1a must be recycled.

[0049] Thanks to the sorting step 116 based on the information contained in or read from the transponder 2, the method of the present invention ensures that the sorting step 116 by type, the sorting step 116, is efficient and reliable. Error-prone and time-consuming laser-optical determination of the chemical and / or mineralogical composition of the molded parts 1, 1a, 1b, or manual sorting is not required. A finer or more detailed sorting step 116 can also be carried out. This is because the transponder 2 can contain information not only about the main components, but also about secondary components such as binders and additives, allowing sorting on this basis. This means that the quality of the recycled products can be further improved.

[0050] The method of the invention makes it possible to classify the shaped articles 1, 1a, 1b not only according to their chemical and / or mineralogical composition, but also, for example, according to the origin of the raw materials and / or the effect of their use on the product.

[0051] For example, unlike barcodes, transponders 2, preferably RFID transponders, can be read even when optical methods are not available. Furthermore, as mentioned above, information can be recorded and output from a continuous process in multiple steps. Preferably, data is recorded in situ as mentioned above and can be used for sorting step 116.

[0052] Of course, it is also within the scope of the present invention that the transponder 2 already contains information, in particular product-specific information, before it is attached to the fire-resistant molding 1, 1a. This information can also be applied to the transponder 2 before the quality control (step 107). All that matters is that the information is present in the transponder 2 before the installation of the molding 1, 1a (step 112).

[0053] The transponder 2 may contain only a label for uniquely identifying the article 1, 1a, and no other product-specific information, in which case the sorting criteria used for sorting cannot be directly read.

[0054] The assignment of the label to the product characteristics, in particular the recipe, is carried out only by data processing after the transponder 2 has been read. In this case, for example, all the product-specific information required for the respective molded part 1, 1a, in particular the recipe, is stored in a database.

[0055] This also applies to all other information. In principle, the sorting criteria used for sorting do not need to be read directly from the transponder 2. Instead, information can be stored on the transponder 2 and read out, with the sorting criteria and other information assigned to that information being stored in a database. As mentioned above, the information stored on the transponder 2 could be, for example, a recipe number or other information to uniquely identify the molded part 1, 1a.

[0056] In this case, the transponder 2 may be a simpler transponder 2 equipped only with a microprocessor without rewritable memory, or a SAW (Surface Acoustic Wave) transponder.

[0057] Finally, it is pointed out that all of the above-mentioned, particularly claimed, features of the sorting method and / or recycling method are particularly advantageous in themselves and in any combination and are the subject of the present invention.

[0058] In particular, all of the above-mentioned information read from the transponder and / or all of the information used to process the information read from the transponder may be combined with one another in any combination.

Claims

1. A method for sorting (116) preferably crude ceramic refractory shapes (1, 1a, 1b), preferably bricks, comprising the steps of: said molded articles (1, 1a, 1b) are selected at least on the basis of their mineralogical and / or chemical composition, The molded articles (1, 1a, 1b) have a transponder (2) that can be read for sorting, 10. A method for sorting, characterized in that the molded articles (1, 1a, 1b) are sorted at least with respect to their mineral and / or chemical composition based on the information read or by processing the information read.

2. 2. The sorting method according to claim 1, wherein sorting criteria for sorting the molded parts (1, 1a, 1b) are read directly from the transponder (2) and / or determined by data processing from the information read from the transponder (2).

3. 3. The sorting method according to claim 1 or 2, wherein the transponder (2) contains information about the mineral and / or chemical composition of the molded parts (1, 1a, 1b), and the molded parts (1, 1a, 1b) are sorted based on at least the information about the mineral and / or chemical composition.

4. 3. The method of claim 1, wherein the information read from the transponder (2) and / or the information used to process the information read from the transponder (2) is one or more of the following: -Recipe -Manufacturing date - Internal recipe number - information about the manufacturing process of said molded article (1, 1a), in particular the mixing time and / or pressing pressure and / or firing temperature; - Waste code number - Place of use of said molded article (1, 1a) - the operating time of the molded article (1, 1a) - the temperature conditions inside the plant (4) in the aggregate (5), preferably in the furnace (6), in which said moulded articles (1, 1a) are used; the atmosphere inside the plant (4) of the aggregate (5) in which the moulded articles (1, 1a) are used, preferably the furnace (6), and in particular the alkali content of said atmosphere; - Pallet number

5. 5. The method according to claim 1, wherein the molded parts (1, 1a, 1b) have an RFID transponder as the transponder (2).

6. 6. A method according to any one of claims 1 to 5, wherein the moulded parts (1, 1a, 1b) comprise passive transponders.

7. 7. A method according to any one of claims 1 to 6, wherein the transponder (2) comprises temperature and / or humidity and / or atmospheric pressure measuring means.

8. 8. The method according to claim 1, wherein the molded products (1, 1a, 1b) are at least partly aggregates (5), preferably molded products (1b) that have been used in a furnace (6) or a transport container and then crushed and removed after use.

9. The transponder (2) includes a plurality of transponders (2), 9. The sorting method according to claim 8, wherein the transponders (2) are each arranged in a recess (7) on the cold side (3b) of the crushed molded product (1b).

10. 10. The sorting method according to claim 8 or 9, wherein the crushed molded articles (1b) are molded articles (1b) of fire-resistant lining products and / or functional products.

11. 11. The method according to claim 1, wherein the molded articles (1, 1a, 1b) are at least partly unusable molded articles (1, 1a), in particular waste (1, 1a) arising during production, and / or molded articles (1, 1a) that have been altered during storage and / or transport, preferably hydrated.

12. 12. The method according to any one of claims 1 to 11, wherein at least some of the molded parts (1, 1a) are overproduced molded parts (1, 1a).

13. 1. A method for recycling aggregates (5), preferably crude ceramic refractory moldings (1, 1a), preferably bricks used in furnaces (6) or transport containers, comprising: a) crushing the aggregates (5), preferably the moulded pieces (1; 1a) of the furnace (6); b) sorting the crushed moulded articles (1b) based at least on their mineralogical and / or chemical composition; c) reprocessing the preferably selected molded articles (1b), 13. A recycling method, characterized in that the crushed molded articles (1b) have transponders (2) and are sorted by the sorting method according to any one of claims 1 to 12.

14. 14. A method for the reuse of molded articles (1, 1a, 1b) sorted by the sorting method according to any one of claims 1 to 12 or molded articles (1b) recycled by the method according to claim 13, preferably for the production of crude ceramic refractory molded articles or unmolded articles.

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