Unshaped refractory material, method for producing an unshaped wet refractory material, and method for manufacturing a refractory lining

Abstract

The invention relates to a shapeless refractory material, a method for producing a shapeless wet refractory material, and a method for manufacturing a refractory lining.

Description

Unshaped refractory material, method for producing an unshaped wet refractory material, and method for manufacturing a refractory lining The invention relates to an unshaped refractory material, a method of producing an unshaped wet refractory material, and a method of preparing a refractory lining. Refractory materials are materials that can withstand high temperatures. The term "refractory material" as used in this invention refers, in particular, to refractory materials with an operating temperature above 600 °C and preferably to refractory materials in accordance with DIN 51060:2000-06, i.e., materials with a conical pyrometric equivalent >SK17. The conical pyrometric equivalent can be determined in particular according to DIN EN 993-12:1997-06. An "unformed" refractory material refers to a refractory material that does not have a defined shape, meaning it has not been given a specific form through any shaping process, such as pressing. Rather, an unformed refractory material may be found, for example, in bulk or in some other unshaped form. In particular, an unformed refractory material refers to a material that is also called "refractory mass" or "refractory mixture." As is well known, unformed refractory material in the form of refractory mass is introduced into its place of use unshaped and only hardens, dries, and heats there. In particular, linings for high-temperature aggregates can be used in the form of such refractory mass. A typical application of unformed refractory materials is their use in lining high-temperature aggregates in steel production. For example, in one of the final stages of the steelmaking process, molten steel is poured from a ladle into cooled molds. To ensure a continuous casting process and protect the permanent lining of the ladle from corrosion and erosion, the ladle is typically lined with an unformed refractory material (the so-called "wear lining mixture"). Before casting begins, the wear lining mixture must generally be preheated to a temperature of approximately 1000 to 1200 °C to prevent the molten steel from solidifying in the ladle at the start of the casting process.When a temperature within the aforementioned range of approximately 1000 to 1200 °C is reached, the unformed refractory material begins to sinter, forming a ceramic bond and thus acquiring permanent strength during the casting process. The most common wear-resistant coating mixtures for lining a trough are known as "spray-spray slurry mixtures." However, these types of mixtures have a relatively high water content. Therefore, before preheating, spray-spray slurry mixtures must be dried in a comparatively lengthy and energy-intensive drying process. Alternatively, so-called "cold-set slurry mixtures," also known as wear-resistant coating mixtures for lining a trough, have a lower water content and do not require a separate drying process before preheating.These cold-setting mixtures harden through organic compounds in the cold state. However, in the case of cold-setting mixtures, preheating leads to the decomposition of the organic components of the mixture and, therefore, to a loss of strength in the cold-setting mixtures within a temperature range of approximately 600 to 1000 °C, i.e., before a ceramic bond forms. This loss of strength can result in damage or even destruction of the refractory lining based on such cold-setting mixtures. US patents 4778 526 A and 3879 208 A describe non-formed magnesia-based refractory materials comprising citric acid and aluminum sulfate. An object of the invention is to provide an unformed refractory material that hardens with only a small addition of water in the cold state and, at the same time, provides a stable bond until the maximum preheating temperature is reached. In particular, the unformed refractory material shall exhibit a stable bond until reaching a temperature at which the unformed refractory material begins to sinter. In particular, a stable bond shall mean that the unformed refractory material is not substantially damaged or destroyed. In particular, the unformed refractory material must allow for a stable bond over a temperature range from ambient temperature to a temperature in the range of approximately 1000 to 1200 °C. To achieve this objective, according to the invention, a non-formed refractory material is provided comprising: a refractory base component; and a binding component; wherein the binding component comprises, citric acid; and aluminum sulfate; and where the refractory base component is present as a mass of grains, where The grains comprise a fine fraction of grains with a grain size less than 0.063 mm, wherein the fine fraction is present in a proportion in the range of 3 to 30% by mass, based on the total mass of the refractory base component, and wherein The fine fraction comprises CaO in a proportion in the range of 1.5 to 10% by mass, based on the total mass of the fine fraction. Surprisingly, it has been discovered according to the invention that this non-formed refractory material can provide a stable bond through the addition of only a very small amount of water within a temperature range from ambient temperature up to the material's sintering temperature. Specifically, a stable bond can be achieved with only a very small addition of water within a temperature range from ambient temperature up to 1000 to 1200 °C. In particular, this bond is so stable within this temperature range that a wear-resistant trough lining mixture made from the non-formed refractory material according to the invention will not suffer any significant damage from ambient temperature up to the maximum preheating temperature of approximately 1000 to 1200 °C. In particular, it has been discovered according to the invention that such stable bonding of the unformed refractory material according to the invention can now be achieved by adding only 1.0 to 1.9% by mass of water, based on the mass of the unformed refractory material without the water. A significant finding according to the invention is that this stable bond can be achieved by combining the binders with the fine fraction of the refractory base component according to the invention. The refractory base component is present as a granular mass, i.e., in bulk form. This granular mass comprises a fine fraction of grains with a grain size smaller than 0.063 mm (63 µm). This fine fraction with a grain size smaller than 0.063 mm is present in a proportion ranging from 3 to 30% by mass, based on the total mass of the refractory base component. In addition to the proportion of the fine fraction, it is also essential that the fine fraction contains CaO in a proportion ranging from 1.5 to 10% by mass, based on the total mass of the fine fraction. According to the invention, it has been found that, based on the non-formed refractory material according to the invention, the bond stability increases if the amount of the fine fraction approaches a range of 10-15% by mass. Preferably, therefore, the fine fraction can be present in a proportion of at least 3% by mass, more preferably at least 7% by mass, and even more preferably at least 10% by mass, in each case, based on the total mass of the refractory base component. Furthermore, it can be provided that the fine fraction is present in a proportion of at most 30% by mass, more preferably at most 17% by mass, and even more preferably at most 15% by mass, in each case, based on the total mass of the refractory base component.Furthermore, therefore, it can be expected that the fine fraction will be present in a proportion in the range of 7 to 17% by mass and even more preferably in a proportion in the range of 10 to 15% by mass, in each case based on the total mass of the refractory base component. With regard to the proportion of CaO in the fine fraction, according to the invention, it has been found that, based on the non-formed refractory material according to the invention, bond stability increases if the amount of CaO in the fine fraction approaches a range of 2 to 6% by mass. Preferably, therefore, it can be foreseen that the fine fraction comprises a CaO proportion of at least 1.5% by mass and even more preferably at least 2% by mass, in each case based on the total mass of the fine fraction. Furthermore, it can be foreseen that the fine fraction comprises a CaO proportion of at most 10% by mass, more preferably at most 8% by mass, and even more preferably at most 6% by mass, in each case based on the total mass of the fine fraction.Furthermore, it can therefore be anticipated that the fine fraction comprises a proportion of CaO in the range of 2 to 8% by mass and even more preferably in a proportion in the range of 2 to 6% by mass, in each case based on the total mass of the fine fraction. The proportion of the fine fraction is preferably determined by a granulometric analysis, in particular preferably in accordance with ISO 1927-3:2012-12. According to the invention, it has been found that the stable bond achievable with the non-formed refractory material according to the invention can be adversely affected by the presence of certain oxides in the fine fraction. Preferably, therefore, it can be anticipated that certain oxides, in particular Fe₂O₃, Al₂O₃, and SiO₂, are present in certain maximum proportions in the fine fraction. According to one embodiment, the fine fraction is anticipated to comprise the following oxides in the following proportions, each based on the total mass of the fine fraction: CaO: from 1.5 to 10% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: less than 7% by mass; MgO: the remainder up to 100% by mass. The proportions of CaO in the fine fraction may also be present in the proportions shown above. The proportions of oxides in the fine fraction mentioned above are the chemical proportions of these oxides in the fine fraction. Therefore, it is not necessary for the oxides to be present in the form of pure oxide in the fine fraction. Preferably, the proportions of oxides in the fine fraction are determined by X-ray fluorescence (XRF) analysis, preferably according to ISO 12677:2011-10. The binding component of the non-formed refractory material according to the invention comprises citric acid and aluminum sulfate. According to a preferred embodiment, citric acid is present in powder form. According to a further preferred embodiment, the aluminum sulfate is present in powder form. A particular advantage of the presence of citric acid and aluminum sulfate in powder form is that these powders can be distributed very easily and uniformly throughout the volume of the unformed refractory material according to the invention, in particular, for example, more easily than the wet components. This uniform distribution of the binding components throughout the volume of the unformed refractory material also results, in particular, in very uniform stability of the material after the addition of water. Another advantage of the presence of the binding components in powder form is, in particular, that unwanted hardening of the material according to the invention can be avoided before adding water. According to a preferred embodiment, the unformed refractory material according to the invention comprises citric acid in a proportion in the range of 1.6 to 6% by mass, based on the total mass of the refractory base component and the binder component. According to the invention, it has been found that a stable bond can be achieved using the non-formed refractory material of the invention, particularly when citric acid is present in the specified proportion. It has further been found that a stable bond can be further improved and that handling the material according to the invention is particularly easy when the amount of citric acid approaches a proportion of 2 to 3% by mass. Therefore, it can preferably be provided that the citric acid is present in a proportion of at least 1.6% by mass, more preferably in a proportion of at least 1.8% by mass, and even more preferably in a proportion of at least 2% by mass, based in each case on the total mass of the refractory base component and the binder component.Additionally, it can be expected that citric acid will be present in a proportion of at most 6% by mass, more preferably at most 5% by mass, and even more preferably at most 3% by mass, based in each case on the total mass of the refractory base component and the binder component. Furthermore, it can be expected that citric acid will be present in a proportion in the range of 1.8 to 5% by mass, and more preferably in a proportion in the range of 2 to 3% by mass, based in each case on the total mass of the refractory base component and the binder component. According to a preferred embodiment, the aluminum sulfate is present in the form of hydrated aluminum sulfate. Preferably, the hydrated aluminum sulfate is in the form of Al2(SO4)3 · x H2O, with x in the range of 14 to 16. According to a further preferred embodiment, the non-formed refractory material according to the invention comprises aluminum sulfate in a proportion in the range of 1 to 5% by mass, calculated as hydrated aluminum sulfate (Al2(SO4)3·14H2O) and based on the total mass of the refractory base component and the binder component. According to the invention, it has been found that a stable bond can be achieved using the non-formed refractory material according to the invention, particularly when aluminum sulfate is present in the specified proportion. It has further been found, according to the invention, that a stable bond can be further improved and that handling the material according to the invention is particularly easy when the amount of aluminum sulfate approaches a proportion of 2 to 3% by mass. Therefore, it can preferably be provided that the aluminum sulfate is present in a proportion of at least 1% by mass and even more preferably in a proportion of at least 2% by mass, calculated in each case as hydrated aluminum sulfate (Al₂(SO₄)₃·14H₂O) and based on the total mass of the refractory base component and the binder component.Additionally, it can be expected that the aluminum sulfate will be present in a proportion of at most 5% by mass, more preferably at most 4% by mass, and even more preferably at most 3% by mass, calculated in each case as hydrated aluminum sulfate (Al₂(SO₄)₃·14H₂O) and based on the total mass of the refractory base component and the binder component. Furthermore, it can be expected that the aluminum sulfate will be present in a proportion in the range of 1 to 4% by mass, and more preferably in a proportion in the range of 2 to 3% by mass, calculated in each case as hydrated aluminum sulfate (Al₂(SO₄)₃·14H₂O) and based on the total mass of the refractory base component and the binder component. As previously stated, the binding components in the form of citric acid and aluminum sulfate can be present in very small proportions in the unformed refractory material according to the invention. The advantage of such small proportions of binder is, in particular, that it also prevents early hydration and hardening of the material according to the invention, making the unformed refractory material according to the invention particularly easy to handle, and in particular, easy to store and transport. The refractory base component constitutes the refractory raw material base of the unformed refractory material according to the invention. Preferably, the refractory base component comprises one or more refractory raw materials. Preferably, the refractory base component is in the form of a basic refractory base component. As is known, basic refractory components consist of raw materials whose main oxide is MgO, e.g., raw materials in the form of magnesia, dolome, or olivine. The refractory base component, in particular a basic refractory base component, therefore preferably comprises one or more basic refractory raw materials. According to a preferred embodiment, the refractory base component comprises at least one of the following refractory raw materials: magnesia and olivine. In a particularly preferred form, the refractory raw material in the form of magnesia is present as sintered magnesia. According to a particularly preferred embodiment, the refractory base component comprises magnesia, in particular sintered magnesia. According to a preferred embodiment, the unformed refractory material comprises sintered magnesia in a proportion of at least 50% by mass, based on the total mass of the base component. Preferably, the unformed refractory material comprises sintered magnesia in this proportion if the refractory base component is composed of magnesia. In the event that the refractory base component comprises the refractory raw materials magnesia and olivine, according to a preferred embodiment, the refractory base component comprises magnesia, in particular sintered magnesia, and olivine in the following mass proportions, each based on the total mass of the refractory base component: magnesia in the range of 10 to 90% by mass and olivine in the range of 90 to 10% by mass; more preferably magnesia in the range of 20 to 60% by mass and olivine in the range of 80 to 40% by mass; even more preferably magnesia in the range of 30 to 50% by mass and olivine in the range of 70 to 50% by mass. According to a preferred embodiment, the refractory base component comprises the following oxides in the following proportions, each based on the total mass of the refractory base component: CaO: from 0.5 to 20% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: less than 35% by mass; MgO: the remainder up to 100% by mass. According to a further preferred embodiment, the refractory base component comprises the following oxides in the following proportions, each based on the total mass of the refractory base component: CaO: from 0.5 to 20% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: 8 to 30% by mass; MgO: 60 to 80% by mass. The refractory base component may be composed of the above oxides, in particular, in the case that the refractory base component is composed of sintered magnesia and olivine. According to a particularly preferred embodiment, the refractory base component comprises the following oxides in the following proportions, each based on the total mass of the refractory base component: CaO: from 0.5 to 20% by mass, preferably from 2 to 6% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: less than 5.5% by mass; MgO: the remainder up to 100% by mass. The refractory base component may be composed of the above oxides, in particular, in the case that the refractory base component is composed of sintered magnesia. The proportions of oxides in the refractory base component mentioned above are the chemical proportions of these oxides in the refractory base component. Therefore, the oxides need not be present in pure oxide form in the refractory base component. Preferably, the proportions of the oxides in the refractory base component are determined by X-ray fluorescence (XRF) analysis, preferably according to ISO 12677:2011-10. The oxidized composition of the entire refractory base component may differ from the oxidized composition of the fine fraction of the refractory base component. In particular, the proportion of CaO in the entire refractory base component may also differ from the proportion of CaO in the fine fraction of the refractory base component. The non-formed refractory material according to the invention may comprise additional components. For example, the non-formed refractory material may comprise at least one prior art sintering aid, for example, boric acid, in a proportion in the range of 0.1 to 1.0% by mass, based on the total mass of the refractory base component, the binder component, and the at least one sintering aid. An additional object of the invention is a method for producing a non-formed wet refractory material, comprising the following steps: to provide a non-formed refractory material according to the present invention; add water to the unformed refractory material. The addition of water to the unformed refractory material according to the invention causes a reaction in the unformed refractory material that results in a bonding of the material. In this respect, it is also particularly advantageous that the two binding components, citric acid and aluminum sulfate, are characterized by high water solubility, so the binding reaction is initiated by the addition of water. This creates an acidic solution in the unformed refractory material, which is able to dissolve cations, especially calcium cations, from the refractory base component, thereby increasing the pH of the solution and precipitating a three-dimensional bonding phase matrix with different citrate-sulfate phases. This achieves a stable bond even at room temperature.The inventors assume that this highly stable bonding phase matrix based on the refractory material according to the invention is enhanced in particular by the fact that the cations, especially calcium cations and possibly also magnesium cations, from the fine fraction of the refractory base component dissolve very readily. As a result, the pH value increases rapidly and significantly, thus improving the formation of the bonding phase. However, the reason for this very rapid and strong formation of a bonding phase matrix in the material according to the invention is currently under further investigation. During the subsequent heat treatment of the unformed refractory material mixed with water, particularly, for example, during preheating of the material in a trough, the organic binding components, especially citric acid, can decompose at temperatures up to approximately 600 °C.However, an advantage of the material according to the invention is that a binding structure consisting of sulfate-containing phases is retained up to a temperature of at least approximately 1000 to 1200 °C. This means that a stable bond can also be maintained in the unformed refractory material within this temperature range of approximately 600 °C to approximately 1000 / 1200 °C. Preferably, it is anticipated that, when carrying out the process according to the invention, water is added in a proportion in the range of 1.0 to 1.9% by mass, based on the total mass of the refractory base component and the binder component of the unformed refractory material without water, to the unformed refractory material. According to the invention, it has been found that the stable bonding and handling of the unformed refractory material mixed with water can be further enhanced by bringing the added water content closer to a proportion in the range of 1.2 to 1.8% by mass. According to a particularly preferred embodiment, it is therefore anticipated that water is added in a proportion in the range of 1.2 to 1.8% by mass, based on the total mass of the refractory base component and the binder component of the unformed refractory material without water, to the unformed refractory material. An additional object of the invention is a non-formed wet refractory material prepared according to the method according to the invention. After adding water to the unformed refractory material according to the invention, the wet unformed refractory material can be used, in particular, in the same way as a regular refractory material, i.e., in the same way as a so-called refractory mass. In particular, the wet unformed refractory material can be used to line a trough. An additional object of the invention is the provision of the non-formed refractory material according to the invention, which further comprises water. Preferably, as stated above, the unformed refractory material comprises water in a proportion in the range of 1.0 to 1.9% by mass and even more preferably in a proportion in the range of 1.2 to 1.8% by mass, based in each case on the total mass of the refractory base component and the binder component without the water. A further object of the invention is the use of the unformed refractory material according to the invention, particularly insofar as the unformed refractory material further comprises water, for lining a surface. This use can be made, in particular, provided that the surface is the surface of a container for holding molten steel, in particular, the surface of a trough. An additional subject matter of the invention is a method for producing a refractory lining, comprising the following steps: providing a non-formed refractory material further comprising water, according to the invention; applying the non-formed refractory material comprising water onto a surface. In particular, the surface can be the surface of a container for holding molten steel, in particular the surface of a trough. Other features of the invention will become apparent from the claims and the exemplary embodiments of the invention described below. All features of the invention can be combined with each other, individually or in combination, in any desired manner. Illustrative embodiments of the invention and a comparative example are explained in more detail below. Illustrative embodiment According to a first embodiment, an unshaped refractory material was provided according to the invention, having the following components according to Table 1: Table 1 The mass fractions according to Table 1 are in each case related to the total of all components of the unformed refractory material according to Table 1. Sintered magnesia represented the basic refractory component of the unformed refractory material. Due to its sintered magnesia-based composition, this refractory base component represented a fundamental refractory component. Aluminum sulfate and citric acid were each in powder form. The aluminum sulfate was present as hydrated aluminum sulfate in the form of Al2(SO4)3·14H2O. The mass fraction of aluminum sulfate in the material shown in Table 1 is calculated based on this hydrated aluminum sulfate. The magnesia sintered in the unformed refractory material according to Table 1 had the chemical composition according to Table 2: Table 2 The mass fractions according to Table 2 are related in each case to the total mass of the sintered magnesia. The mass fractions of oxides were determined by X-ray fluorescence analysis according to ISO 12677:2011-10. All other data on oxides provided below were also determined using this standard. The sintered magnesia, as shown in Table 1, had a fine fraction with a grain size smaller than 0.063 mm, representing 11.5% by mass of the total mass of the sintered magnesia. The proportion of the fine fraction was determined by particle size analysis according to ISO 1927-3:2012-12. The fine fraction of the sintered magnesia had the chemical composition according to Table 3: Table 3 The unformed composite refractory material as indicated above was mixed with 1.5% by mass of water, based on the total mass of the material without water, and blended, thereby obtaining an embodiment of a wet unformed refractory material according to the invention. To determine the strength of this unformed wet refractory material, cylindrical test samples were prepared by filling and removing a cup. These test samples were then allowed to harden for 45 minutes. After 45 minutes, the test samples were checked for dimensional stability and strength. It was subsequently verified that all test samples were fully hardened. The test samples could not be damaged manually. The edges of the samples were stable and resistant to abrasion. Finally, the cold compressive strength (CCS) of the test samples was investigated according to DIN EN ISO 1927-6:2013-04 when heated to a temperature range from ambient temperature to 1200 °C. The results of this series of tests are shown in Table 4: Table 4 In particular, a stable bond can be provided with only a very small addition of water in a temperature range from room temperature to a temperature in the range of 1000 to 1200 °C. The test results clearly demonstrate that, despite the low water content of only 1.5%, a stable bond can be provided, as reflected by the CCS values, across the entire temperature range from room temperature (25°C) to 1,200°C. Comparative example For comparative purposes, another non-formed refractory material that was not an embodiment of the invention (comparative example) was provided. In this regard, the non-formed refractory material according to the comparative example had a composition according to Table 1. However, the sintered magnesia had a different chemical composition compared to the sintered magnesia according to Table 2, namely the following chemical composition according to Table 5: Table 5 In the comparative example, the sintered magnesia had a fine fraction with a grain size of less than 0.063 mm at a proportion of 10.9% by mass, based on the total mass of the sintered magnesia. The chemical composition of the fine fraction was also different compared to the illustrative embodiment of the invention. To date, the fine fraction has had the chemical composition according to Table 6: Table 6 The unshaped refractory material according to this comparative example was mixed with 1.5% water by mass, treated, and shaped into test specimens in the same manner as the embodiment of the preceding example of the invention. Also, in the same manner as in the illustrative embodiment of the invention, the dimensional stability and strength were then checked after 45 minutes. The test specimens were found to exhibit some dimensional stability but absolutely no strength. On the contrary, the test specimens proved to be so loose that they completely disintegrated even upon light touch with a finger. Due to its virtually nonexistent stability even at room temperature, the refractory material not shaped according to the comparative example is therefore unsuitable for any technical application. This is particularly true for its use in, for example, a trough, as a certain degree of stability at room temperature is required for the material to adhere to the trough's side wall. If the material does not adhere to the trough's side wall, heating it to higher temperatures is not technically useful. Furthermore, it must be assumed that the stability decreases even further at elevated temperatures. Additional illustrative realizations Several illustrative embodiments of non-formed refractory materials according to the invention were prepared to determine their strength development at room temperature. These materials had essentially the same composition as the illustrative embodiment described above, with only the amount of binder, i.e., the amount of aluminum sulfate and citric acid in the material, being varied. A total of five embodiments of such materials were prepared, designated 01 to 04 in Table 7. Table 7 The results of the dimensional stability and strength tests are indicated in the last row under "Result". The respective numbers represent the following test results: 3: The test sample was observed to have a rough surface and loose grains. It was possible to slightly deform the test sample with light contact with a finger. 2: The test samples exhibit good resistance. Deformation and destruction of the samples are only possible under higher pressure. Abrasion of the sample edges by hand is possible. 1: The test samples were observed to be fully hardened. The test samples could not be damaged manually. The edges of the samples were stable and resistant to abrasion. This showed that the best results in terms of dimensional stability and strength were observed when aluminum sulfate and citric acid were each present in a proportion of 2.5% by mass.

Claims

1. An unformed refractory material comprising: 1.1 a refractory base component; and 1.2 a binder component; wherein the binder component comprises, 1.2.1 citric acid; and 1.2.2 aluminum sulfate; and wherein 1.3 the refractory base component is present as a mass of grains, wherein 1.3.1 the grains comprise a fine fraction of grains having a grain size of less than 0.063 mm, wherein 1.3.1.1 the fine fraction is present in a proportion in the range of 3 to 30% by mass, based on the total mass of the refractory base component, and wherein 1.3.1.2 the fine fraction comprises CaO in a proportion in the range of 1.5 to 10% by mass, based on the total mass of the fine fraction.

2. The non-formed refractory material according to claim 1, comprising citric acid in a proportion in the range of 1.6 to 6% by mass, based on the total mass of the refractory base component and the binder component. 3.The non-formed refractory material according to at least one of the preceding claims, wherein the citric acid is present as a powder.

4. The non-formed refractory material according to at least one of the preceding claims, wherein the aluminum sulfate is present in the form of hydrated aluminum sulfate.

5. The non-formed refractory material according to at least one of the preceding claims, comprising aluminum sulfate in a proportion in the range of 1 to 5% by mass, calculated as hydrated aluminum sulfate (Al2(SO4)3·14H2O) and based on the total mass of the refractory base component and the binder component.

6. The non-formed refractory material according to at least one of the preceding claims, wherein the aluminum sulfate is present in powder form. 7.The non-formed refractory material according to at least one of the preceding claims, wherein the fine fraction comprises the following oxides in the following proportions, each based on the total mass of the fine fraction: CaO: from 1.5 to 10% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: less than 7% by mass; MgO: the remainder up to 100% by mass.

8. The non-formed refractory material according to at least one of the preceding claims, wherein the refractory base component comprises at least one of the following refractory raw materials: magnesia and olivine.

9. The non-formed refractory material according to claim 8, comprising magnesia in a proportion of at least 50% by mass, based on the total mass of the base component. 10.The non-formed refractory material according to at least one of the preceding claims, wherein the refractory base component comprises the following oxides in the following proportions, each based on the total mass of the refractory base component: CaO: from 0.5 to 20% by mass; Fe2O3: less than 6% by mass; Al2O3: less than 3% by mass; SiO2: less than 35% by mass; MgO: the remainder up to 100% by mass.

11. A method for producing a wet, non-formed refractory material, comprising the following steps: A. providing a non-formed refractory material according to at least one of claims 1 to 10; B. adding water to the non-formed refractory material. 12.The method according to claim 11, wherein 1.0 to 1.9% by mass of water, based on the total mass of the refractory base component and the binder component of the unformed refractory material without water, is added to the unformed refractory material.

13. The unformed refractory material according to at least one of claims 1 to 10, further comprising water.

14. A method for preparing a refractory lining, comprising the following steps: A. providing an unformed refractory material according to claim 13; B. applying the unformed refractory material to a surface.

15. The method of claim 14, wherein the unformed refractory material is applied to the surface of a trough.