Sorting methods and methods for recycling refractory shaped products, preferably stones, and their use

Description

[0001] The present invention relates to a sorting method and a method for recycling, preferably coarse ceramic, refractory, shaped products, preferably stones, as well as the use of the sorted or recycled products.

[0002] The term "refractory" in the context of the invention should not be limited to the definition according to ISO 836 or DIN 51060, which define a cone drop point of > 1500°C. Refractory products within the meaning of the invention have a compression softening point T 0.5 according to DIN EN ISO 1893: 2008-09 of T 0.5 ≥ 600 °C, preferably T 0.5 ≥ 800 °C. Accordingly, refractory or refractory granular materials or grains within the meaning of the invention are those materials or grains that are suitable for a refractory product with the above-mentioned compression softening point T 0.5.

[0003] Refractory products are used to protect aggregate structures in aggregates where temperatures between 600 and 2000 °C, especially between 800 and 1800 °C, prevail.

[0004] In particular, they are used for the refractory lining of thermal processing plants, preferably melting, firing, and heat treatment plants, or transport vessels. However, they can also be functional products (see "Gerald Routschka / Hartmut Wuthnow, Practical Handbook "Refractory Materials," 6th edition, Vulkan-Verlag (hereinafter referred to simply as "Practical Handbook"), Chapter 1.6).

[0005] The refractory lining of a plant or transport vessel, which lines the shell of the plant or transport vessel, can be single- or multi-layered, but is usually multi-layered. The lining has a working lining or wear lining on the fire side or inside the unit, which wears out during use and must be replaced regularly. If the wear lining is made of refractory bricks, their fire side in particular is consumed during use. However, at least some of the bricks can be reused after use and are mechanically removed from the wear lining.

[0006] In addition, the lining can include a permanent lining that connects to the wear lining. The permanent lining then remains in the system or transport vessel for several kiln runs or cycles and serves as a safety lining. An insulating backing can also be connected to the permanent lining.

[0007] Coarse ceramic products are known to be made from grains with sizes up to 6 mm, and in special cases even up to 25 mm (Practical Handbook, Chapter 2). Coarse ceramic products are distinguished from fine ceramics by the grain size of their structural components. If the structural components are at least partially larger than 1 mm, they are classified as coarse ceramics; if the structural components are exclusively ≤ 1 mm, they are classified as fine ceramics.

[0008] Furthermore, a distinction is known between non-basic (Practical Handbook, 4.1) and basic refractory products (Practical Handbook, 4.2). According to DIN EN ISO 10081:2005-05, a distinction is made between non-basic and basic refractory products based primarily on their chemical reaction behavior. The non-basic product group includes materials of the SiO 2 -Al 2 O 3 series and other materials that cannot be further classified according to their chemical reaction behavior, such as SiC and carbon products. A key characteristic of most basic products is that the sum of the oxides MgO and CaO predominates. Chromite, picrochromite, spinel, and forsterite bricks are also considered basic products, even though they are almost neutral.

[0009] In the case of heavy clay products, a distinction is also made between shaped and unshaped products.

[0010] Shaped heavy clay products are unfired, possibly tempered, or ceramically fired products, preferably manufactured in a ceramic factory, especially bricks or slabs. They have a defined geometry and are ready for installation. Shaping is achieved, for example, by pressing, stamping, ramming, or slip casting. The shaped products, especially the bricks, are then laid with mortar or mortar-free ("crunching"), for example, to form the lining. The production process for shaped heavy clay products is typically divided into the following steps (Practical Handbook, page 14 / Section 2.1): Preparation Mixing Shaping Drying (if necessary) Thermal treatment up to 800 °C or firing Post-treatment (if necessary)

[0011] Unformed products (Practical Handbook, page 142 / Section 5) are products that are formed into their final shape, usually by the user, from an unformed fresh mass or lumps, e.g., by pouring, vibrating, poking, tamping, or spraying. Unformed products are usually placed behind formwork in larger sections at the site of use and, after hardening, form part of the lining. Examples of unformed products include shotcrete, tamping, casting, vibrating, or potting compounds.

[0012] The recycling of refractory products is becoming increasingly important for economic and ecological reasons, as well as due to resource scarcity. The reuse of recycled materials (recyclates) to produce new refractory products offers the advantages of more cost-effective starting materials, lower processing costs, lower energy consumption, and reduced carbon dioxide emissions compared to primary raw materials.

[0013] However, for the excavated products to be reused, they must be sorted into separate types. This is because, after excavation, a mixture of different product types usually remains. Furthermore, depending on the location and time of use, the products were subjected to different stresses and may have undergone chemical / mineral alterations, meaning that not all products are suitable for reuse or for the production of different products. The excavated products may be contaminated, for example, by infiltration and / or adhesion of slag, clinker melts, metals, salts, or other process media.

[0014] In order to enable a separation of the extracted products based on their chemical / mineral composition, it is known in the field to carry out a chemical analysis of the products using laser emission spectroscopy (LIBS) (see e.g. https: / / cordis.europa.eu / article / id / 197342-how-to-turn-refractory-waste-back-into-raw-materials / deMulti-element analysis is used to classify different refractory materials. In particular, the main components and some additives can be determined.

[0015] However, this method cannot always fully characterize the chemical / mineral properties of refractory products. For example, it is not possible to definitively determine whether the refractory products contain carbon. This is due to the surface changes that occur during use. The carbon burns out on the fire side of the products. Since the penetration depth in LIBS measurements is generally limited to a few hundred µm, it may happen that no carbon is detected even though the product contains carbon.

[0016] Furthermore, it is known in the field to provide fire-resistant products with a sensor or a chip for various purposes.

[0017] WO 2008 / 135135 A2, for example, discloses a ceramic component that has an integrated sensor for data acquisition and transmission, where the acquired information includes component identification, physical properties of the component, movements of the component, usage time of the component, or location of the component. The objective is to enable identification and statements about the condition and usage time of the component before, during, and after use. The information for identifying the component includes, for example, the product type, material grades, manufacturer specifications, manufacturing, delivery, and usage dates. In particular, predictions about the wear state of the component are to be made based on, for example, temperature measurements and measurements of mechanical stress over time, so that it is replaced in a timely manner, but not too early.WO 2008 / 135135 A2 does not deal with the recycling of components.

[0018] WO 2020 / 254134 A1 also deals with the use of sensors, e.g., RFID chips, in refractory components, such as slide gates. This concerns the monitoring and tracking of replaceable refractory components in a metallurgical plant.

[0019] EP 3 119 915 B1 discloses a metallurgical container with a wirelessly readable transponder.

[0020] WO 2010 / 057656 A1 deals with a device for actively tracking specific data relating to systems or their components in a metallurgical plant. Each component is permanently connected to at least one writable and readable storage medium, e.g., an RFID chip, for the specific data, and the specific data can be changed periodically and / or based on input. Among other things, the data includes physical, mechanical, and / or chemical properties of the components.

[0021] DE 203 06 019 U1 discloses a sorting machine using transponders, whereby specific objects are selectively separated from a stream of sorted goods, and the information relevant for sorting is obtained using a radio frequency identification system. The objects identified are those equipped with a transponder and located within the detection range of at least one reader. The relevant information includes, for example, information on the material composition and / or use and / or production. The sorting machine sorts out used packaging such as plastic bottles, plastic bottles made of a specific material, and silicone cartridges. At least the objects to be sorted out carry a transponder.

[0022] The object of the present invention is to provide a sorting method for sorting shaped products, preferably stones, preferably coarse-ceramic, refractory, preferably used in an aggregate, preferably a furnace, and broken out of this after use, which ensures efficient and precise sorting of the broken out products.

[0023] Further objects of the present invention are to provide a method for recycling the broken products and to provide a use for the broken products.

[0024] The object is achieved by a sorting method having the features of claim 1, a recycling method having the features of claim 11, and a use having the features of claim 12. Advantageous developments of the invention are characterized in the subsequent subclaims.

[0025] The invention is explained in more detail below using a drawing as an example. The drawings show: Figure 1: Schematic representation of the life cycle of fired refractory products with inventive recycling Figure 2: Schematic representation of the life cycle of unfired refractory products with inventive recycling Figure 3: Schematic representation of a cross-section through a refractory brick with an integrated transponder

[0026] In Figure 1 the life cycle 100 of refractory, shaped, fired products 1 is shown schematically.

[0027] Accordingly, the raw materials used for production are first prepared 101 in a conventional manner. These are primary raw materials and secondary raw materials. Subsequently, the prepared raw materials are mixed 102 and the mixture is shaped 103, preferably pressed 104, into shaped, unfired products 1a. The shaped, in particular pressed, unfired products 1a are then ceramically fired 105 in a furnace.

[0028] According to the invention, after firing, the fired products 1 are provided or fitted 106 with at least one transponder 2. Subsequently, a quality control 107 of the fired products 1 preferably takes place.

[0029] A transponder 2 is known to be a radio communication device that receives incoming signals and automatically responds to or forwards them. A transponder 2 is known to receive and / or transmit information from a transmitting and / or receiving unit 8 using a contactless process.

[0030] The transponder 2 comprises, in a conventional manner, a coupling element, e.g., an antenna, and a microchip. The microchip comprises an analog circuit for receiving and transmitting (transceiver), as well as a digital circuit, preferably a microcontroller, and a memory. The memory is a memory that can be written to at least once. The memory contains the unchangeable, in particular unique, identity of the transponder 2. Preferably, however, it is a memory that can be written to multiple times, so that information can be stored and / or modified repeatedly during the lifetime of the transponder 2.

[0031] Transponder 2 is preferably a passive transponder 2.

[0032] As is known, a passive transponder 2 obtains the energy required for communication and for processing internal processes exclusively from the electromagnetic field of the transmitting and / or receiving unit 8.

[0033] Preferably, the transponder 2 is also an RFID (radio-frequency identification) transponder 2.

[0034] In addition, the transponder 2 preferably has means for measuring temperature and / or means for measuring humidity.

[0035] Furthermore, the unfired and fired products 1; 1a have a product fire side or hot side 3a and a cold side 3b opposite it. When the products 1 are installed, the hot side 3a faces a fired unit interior or combustion chamber 4 of a unit 5, preferably a furnace 6. The cold side 3b faces away from the combustion chamber 4.

[0036] Preferably, the transponder 2 is arranged, positioned, or attached in a recess or depression 7 in the cold side 3b of the product 1. The arrangement on the cold side 3b of the product ensures that the temperature load on the transponder 2 during use is as low as possible. The arrangement of the transponder 2 in the depression 7 additionally ensures mechanical protection of the transponder 2. In particular, it ensures that the transponder 2 is not damaged during handling of the products 1, during transport, and during installation and removal of the product 1.

[0037] According to the invention, product-specific information is now applied 108 to the transponder 2 by means of a known transmitting / receiving unit 8, wherein at least information relating to the chemical and / or mineral composition of the respective product 1 is applied or stored. The product-specific information is preferably the recipe. The recipe contains all materials used to manufacture the product, thus in particular also the main and secondary components used, in particular the additives. Preferably, the recipe also contains information relating to the chemical composition of the materials used, in particular the content of impurities, such as the iron content. In particular, the presence and proportion of the additives cannot be determined, at least not easily, using the known methods.

[0038] Furthermore, at least one of the following information is preferably applied or stored: Production date Internal recipe number Information on the manufacturing process, in particular the mixing time and / or the pressing pressure and / or the firing temperature Waste key number A pallet number for tracking purposes

[0039] Using the production date, for example, in combination with the recipe number, the materials used in production and their composition can also be determined if the associated data is stored in a database. In this case, storing the entire recipe on transponder 2 is not necessary.

[0040] After the information has been applied 108, the fired products 1 are preferably packaged 109 and transported 110 to the place of use.

[0041] After arrival at the site, further information may be applied 108 to the transponder 2 and / or information may be read out 111.

[0042] In particular, the information read out can be incorporated into the plant operators’ goods management systems.

[0043] Subsequently, the installation or installation 112 of the products 1 in the unit 5 takes place. In particular, the refractory lining or refractory lining 113 of the unit 5 is carried out with the refractory products 1. The refractory products 1 are preferably used either to produce a wear lining or a permanent lining or an insulating backing. Thus, after installation 112, they form part of a lining 9 of the unit 5, in particular part of the wear lining or the permanent lining or the insulating backing.

[0044] Before or after installation 112, further information is preferably applied 108 to the transponder 2, in particular information regarding the location of use, in particular the unit 5 itself, and preferably the zone within the unit 5, preferably the furnace 6, and / or the assembly method. Regarding the assembly method, information regarding whether the products 1 are mortared together or not can be applied.

[0045] Subsequently, the products 1 are inserted 114 into the unit 5, preferably into the furnace 6.

[0046] If the transponders 2 are configured for this purpose, a preferably continuous temperature measurement and / or a humidity measurement and / or an atmosphere measurement is preferably carried out by the respective transponder 2 during use, i.e. in-situ. The transponder 2 also stores these measurement results.

[0047] After a certain period of use, the products 1 are removed or broken out 115 from the unit 5, preferably the furnace 6.

[0048] Preferably, after the breaking out 115, further information is applied 108 to the transponder 2 of the broken-out products 1b, in particular information relating to the use 114 of the products 1, preferably information about the time of use and / or the temperature regime in the interior of the plant or combustion chamber 4 and / or the atmosphere in the interior of the plant or combustion chamber 4, in particular the alkali content of the atmosphere and / or the material produced or processed in the unit 5, preferably the furnace 6, and / or the raw materials used for this purpose.

[0049] The information on the use of products 1 can also be used to make predictions about the mineral and / or chemical composition of the excavated products 1b if they are subjected to such stress that they change during use.

[0050] Subsequently, the broken-out products 1b are sorted 116. According to the invention, the sorting 116 is carried out, among other things, based on the information contained on the transponder 2 regarding the mineral and / or chemical composition of the products 1b. For this purpose, the information is read 111 from the transponder 2 before the sorting 116.

[0051] The information read out is processed by a data processing program or by a data processing system and / or by an operator and used for sorting.

[0052] In particular, during sorting 116, the products 1b are classified into different material fractions. Depending on whether the material fractions are reusable or not, the products 1b are either returned 117 and reused or disposed of legally 118.

[0053] For reuse, the reusable products 1b are returned to the manufacturing process for the production of new refractory products 1, in particular they are reprocessed.

[0054] The reusable products 1b can be used either for the production of products 1 of the same product types or for other refractory products. For example, they can also be used for the production of unshaped refractory products (not shown).

[0055] Figure 2 shows a life cycle 100a of unfired, shaped, refractory products 1a.

[0056] In contrast to the fired products 1, instead of firing 105, only a heat treatment 119 at up to a maximum of 800°C is preferably carried out. The unfired products 1a are then fired in situ during use 114 in a manner known per se.

[0057] Information about the use of unfired products 1a is particularly advantageous for sorting, as these usually undergo chemical and / or mineral changes during use.

[0058] Furthermore, according to the invention, fired or unfired products 1;1a are also sorted which were not used in an aggregate 5 but still need to be recycled.

[0059] In particular, products 1;1a must be recycled if they have exceeded their shelf life or have been altered for other reasons during storage or transport to the point where they are no longer usable. For example, magnesia bricks may be exposed to excessively high humidity during storage or transport for too long, causing them to hydrate and thus become unusable.

[0060] This can be determined, for example, by reading the transponder 2 if it has means for measuring humidity.

[0061] In addition, the waste generated during the manufacture of products 1;1a or products 1;1a resulting from overproduction must be recycled.

[0062] The method according to the invention ensures a pure, efficient, and reliable sorting 116 based on the information contained on the transponder 2 or the information(s) read by it. No error-prone and complex laser-optical determination of the chemical and / or mineralogical composition of the products 1; 1a; 1b and / or manual sorting is necessary. A much finer or more detailed sorting 116 can also be performed. This is because the transponder 2 can contain not only information regarding the main components, but also the secondary components, e.g., the binding agent and additives, so that sorting can also be based on this. This allows the quality of the recyclates to be further improved.

[0063] The method according to the invention also makes it possible to classify the products 1;1a;1b not only according to their chemical and / or mineralogical composition, but also, for example, according to the origin of the raw material and / or the influence of the use on the product.

[0064] Unlike barcodes, for example, the transponders 2, preferably RFID transponders, can be read even when optical methods cannot be used. Furthermore, as described, information from sequential processes can be recorded and output in multiple steps. Preferably, even in-situ data is recorded, as explained, which can be used during sorting 116.

[0065] It is, of course, also within the scope of the invention that the transponders 2 already contain information, in particular product-specific information, before they are attached to the fire-resistant product 1;1a. The information can also be applied to the transponder 2 before the quality control 107. It is only important that it is present on the transponder 2 before the installation 112 of the products 1;1a.

[0066] It is also possible that the transponders 2 only contain a marking for the unique identification of product 1;1a without any further product-specific information. The sorting criteria used for sorting are then not directly readable.

[0067] The assignment of the marking to the product properties, in particular the recipe, then only occurs after the transponder 2 has been read by data processing. In this case, for example, all necessary product-specific information, in particular the recipe, for the respective product 1;1a is stored in a database.

[0068] This also applies to all other information. In principle, the sorting criteria used for sorting do not have to be directly readable by transponder 2. Rather, a piece of information can be stored on transponder 2, which is then read out, and the sorting criteria assigned to the information and, if applicable, other information are stored in a database. As already explained, the information stored on transponder 2 can be, for example, the recipe number or other information for the unique identification of product 1;1a.

[0069] In this case, in particular, the transponder 2 may also be a simpler transponder 2 with only a microprocessor without rewritable memory or a SAW (surface acoustic waves) transponder.

[0070] Finally, it is pointed out that all mentioned, particularly claimed, features of the sorting process and / or the recycling process are particularly advantageous in themselves and in any combination and are the subject of the present invention.

[0071] 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 can be combined with each other in any combination.

Claims

1. Sorting method for sorting (116), preferably coarse ceramic, refractory, shaped products (1;1a;1b), preferably bricks, wherein the products (1;1a;1b) are sorted at least on the basis of their mineral and / or chemical composition, wherein the products (1;1a;1b) comprise a transponder (2) which is read out for sorting and the products (1;1a;1b) are sorted at least with regard to their mineral and / or chemical composition on the basis of or by processing the read-out information, and wherein the products (1;1a;1b) are a) at least partially products (1b) used in an aggregate (5), preferably a furnace (6) or a transport vessel, and broken out of this after use, and / or b) at least partially products (1;1a) that are unusable for use, in particular waste products (1;1a) that incur during manufacture and / or products (1;1a) that have changed, preferably hydrated, during storage and / or transport.

2. Sorting method according to claim 1, characterized in that the sorting criteria on the basis of which the products (1;1a; 1b) are sorted are read directly from the transponder (2) and / or are determined by means of data processing from the information read from the transponder (2).

3. Sorting method according to claim 1 or 2, characterized in that the transponder (2) comprises information relating to the mineral and / or chemical composition of the product (1;1a;1b) and the products (1;1a;1b) are sorted at least on the basis of this information.

4. Sorting method according to claim 1 or 2, characterized in that 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 - Production date - Internal recipe number - Information on the manufacturing process of the products (1;1a), in particular the mixing time and / or the pressing pressure and / or the firing temperature - Waste code number - Place of use of the products (1;1a) - Operating time of the products (1;1a) - Temperature regime in a plant interior (4) of an aggregate (5), preferably a furnace (6), in which the products (1;1a) were used - Atmosphere in the plant interior (4) of the aggregate (5), preferably of the furnace (6), in which the products (1;1a) were used, in particular alkali content of the atmosphere - Pallet number.

5. Sorting method according to one of the preceding claims, characterized in that the products (1;1a;1b) comprise an RFID transponder as transponder (2).

6. Sorting method according to one of the preceding claims, characterized in that the products (1;1a;1b) comprise a passive transponder (2).

7. Sorting method according to one of the preceding claims, characterized in that the transponder (2) comprises means for temperature measurement and / or means for humidity measurement and / or means for atmospheric measurement.

8. Sorting method according to one of the preceding claims, characterized in that the transponders (2) are each arranged in a recess (7) in a product cold side (3b) of the broken-out product (1b).

9. Sorting method according to one of the preceding claims, characterized in that the broken-out products (1b) are products (1b) of a refractory lining and / or functional products.

10. Sorting method according to one of the preceding claims, characterized in that some of the products (1;1a) are products (1;1a) from overproduction.

11. Method for recycling coarse ceramic refractory shaped products (1;1a), preferably bricks, used in an aggregate (5), preferably a furnace (6) or a transport vessel, comprising the following method steps: a) Breaking out the products (1;1a) of the aggregate (5), preferably the furnace (6), b) Sorting the broken-out products (1b) at least on the basis of their mineral and / or chemical composition, c) Preferably reprocessing the sorted products (1b), wherein the broken-out products (1b) comprise a transponder (2) and are sorted according to the sorting method according to one of the preceding claims.

12. Reuse of products (1;1a;1b) sorted according to the sorting method according to any one of claims 1 to 10 or of products (1b) recycled according to the method according to claim 11 for the production of, preferably, coarse ceramic, refractory, shaped or unshaped products.