Binder for refractory material, refractory material comprising same and preparation method thereof

Abstract

The present invention relates to a binder for a refractory material, a refractory material comprising same and a preparation method thereof, the binder comprising: resin including a first unit derived from 5-(hydroxymethyl)furfural, a second unit derived from levoglucosan, and a third unit derived from disaccharides; and phosphoric acid.

Description

Binder for refractory material, refractory material containing same, and method for producing same

[0001] The present invention relates to a binder for a refractory material capable of producing a refractory material having excellent physical properties such as heat properties, strength, and erosion resistance and generating less harmful gases when exposed to high temperatures, a refractory material including the same, and a method for producing the same.

[0002] [Cross-reference with related applications]

[0003] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0126682, filed September 21, 2023, the entire contents of which are incorporated herein by reference.

[0004] Refractories typically used in iron and / or steelmaking processes require high corrosion and heat resistance, and are primarily used in electric furnaces, converters, ladles, and torpedo cars. Conventional refractories have been manufactured using phenolic resins as binders. However, refractories manufactured using phenolic resins undergo thermal decomposition due to the heat generated during iron and steelmaking, generating various hazardous decomposition gases. These hazardous decomposition gases are known to have adverse effects on the human body, as they contain large amounts of aromatic organic compounds. In particular, these hazardous decomposition gases, such as phenol, cresol, and xylenol, have strong, irritating odors, causing serious stench and polluting the work environment and surrounding environment.

[0005] To address these issues, preheating the refractory material until the phenol resin's thermal decomposition was complete was used. However, this method had limitations, such as limited odor reduction and negatively impacting the refractory's physical properties. Furthermore, this preheating method generated hazardous gases at the manufacturing site, not just at the point of use, making it a fundamental solution.

[0006] As an alternative, Korean Patent No. 967408 (Patent Document 1) discloses a carbon-containing refractory composition comprising a carbon-containing refractory aggregate and a binder, wherein the binder comprises magnesium sulfate, lignosulfonate, and water. However, as in Patent Document 1, refractory materials containing magnesium sulfate, lignosulfonate, etc., suffer from thermal decomposition upon exposure to high temperatures, resulting in poor hot properties and poor corrosion resistance.

[0007] Therefore, there is a need for research and development on a binder for refractory materials that can produce refractory materials with excellent properties such as high temperature properties, strength, and corrosion resistance and that produce less harmful gases when exposed to high temperatures, a refractory material including the binder, and a method for producing the same.

[0008]

[0009] Accordingly, the present invention aims to provide a binder for a refractory material capable of producing a refractory material having excellent physical properties such as heat properties, strength, and erosion resistance and generating less harmful gases when exposed to high temperatures, a refractory material including the same, and a method for producing the same.

[0010] The present invention provides a binder for a fire refractory, comprising a resin comprising a first unit derived from 5-(hydroxymethyl)furfural, a second unit derived from levoglucosan, and a third unit derived from a disaccharide; and phosphoric acid.

[0011] In addition, the present invention relates to a binder for the above refractory material; and

[0012] A refractory material is provided, including a refractory aggregate.

[0013] Furthermore, the present invention provides a method for producing a binder for a refractory material, comprising the step of stirring and heating a binder composition comprising disaccharide, phosphoric acid and citric acid.

[0014] The fireproofing binder according to the present invention is environmentally friendly because it does not emit aromatic organic compounds that are generated by thermal decomposition upon heating, which is a problem with conventional binders such as phenolic resins. In addition, while phenolic resins require a curing time of 3 to 24 hours after mixing, the fireproofing binder according to the present invention can be molded immediately after mixing, resulting in excellent productivity. Furthermore, its excellent mixability allows for a shortened mixing time. Furthermore, while thermoplastic resins such as phenolic resins require heat treatment above a certain temperature to develop strength after molding, the fireproofing binder according to the present invention, as an aqueous binder, can significantly shorten the drying time, thereby saving energy costs.

[0015] In addition, the refractory material containing the above-mentioned refractory binder has excellent properties such as hot properties, strength, and erosion resistance, and thus can be applied to industrial fields that use high-temperature molten materials, such as iron and steel manufacturing. In particular, the refractory material has excellent refractory properties, and thus can be applied to various fields, such as electric furnaces, ladles, converters, torpedo cars, and refining processes such as iron and steel manufacturing.

[0016] Figure 1 shows the results of GC-MS analysis of a liquid binder for refractory materials according to one embodiment of the present invention.

[0017]

[0018] The present invention is described in detail below.

[0019] Binder for refractory materials

[0020] The liquid binder for a refractory material of the present invention comprises a resin comprising a first unit, a second unit, and a third unit; and phosphoric acid.

[0021] The above-mentioned refractory binder is in liquid form, has excellent storage stability, excellent compatibility with refractory materials, and is environmentally friendly as it does not emit harmful gases, which is a problem with phenol resins.

[0022] The resin comprises a first unit derived from 5-(hydroxymethyl)furfural (5-HMF), a second unit derived from levoglucosan, and a third unit derived from a disaccharide.

[0023] The first unit derived from the above 5-(hydroxymethyl)furfural may have a structure represented by the following chemical formula 1.

[0024]

[0025] In addition, the first unit derived from 5-(hydroxymethyl)furfural may be included in an amount of 10 to 60 wt% based on 100 wt% of the total resin, for example, 15 to 55 wt%, 25 to 50 wt%, 43 to 49 wt%, and particularly 45 to 48 wt%. If the content of the first unit in the resin is less than the above range, the specific gravity of the manufactured refractory material may decrease or the porosity may increase, which may cause problems such as a shortened service life of the refractory material when used at high temperatures, and if it exceeds the above range, problems such as a manufacturing defect of the manufactured refractory material may occur.

[0026] The second unit derived from the above levoglucosan may have a structure represented by the following chemical formula 2.

[0027]

[0028] In addition, the second unit derived from levoglucosan may be included in an amount of 10 to 30 wt% based on 100 wt% of the total resin, for example, 12 to 28 wt%, particularly 15 to 25 wt%. If the amount of the second unit in the resin is less than the above range, the specific gravity of the manufactured refractory material may decrease or the porosity may increase, resulting in problems such as a shortened service life of the refractory material when used at high temperatures. If the amount exceeds the above range, problems such as a manufacturing defect in the manufactured refractory material may occur.

[0029] The third unit derived from the disaccharide may be a unit derived from a disaccharide, at least one selected from the group consisting of sucrose, lactose, maltose, trehalose, cellobiose, and chitobiose. The third unit may be in a form in which some of the hydroxyl groups at the terminal of the disaccharide are removed by participating in a bond. That is, the third unit may include a form produced by reaction after some of the hydrogens at the terminal hydroxyl groups of the disaccharide are removed.

[0030] The phosphoric acid can serve as a catalyst when synthesizing a binder composition. Furthermore, the phosphoric acid increases the bonding strength of a refractory when manufacturing a refractory using a binder containing the phosphoric acid.

[0031] The above binder may be prepared from a binder composition comprising a disaccharide, phosphoric acid, and citric acid. Specifically, the binder composition may comprise 100 parts by weight of citric acid, 50 to 200 parts by weight or 70 to 150 parts by weight of phosphoric acid, and 200 to 400 parts by weight or 250 to 350 parts by weight of disaccharide. If the content of phosphoric acid relative to the content of citric acid in the binder composition is below the above range, problems such as poor handling due to a decrease in the strength of a dried product after manufacturing a refractory may occur, and if it exceeds the above range, problems such as a decrease in the service life of the manufactured refractory when used at high temperatures may occur. On the other hand, if the content of disaccharide relative to the content of citric acid in the binder composition is below the above range, the specific gravity of the manufactured refractory material may decrease or the porosity may increase, causing problems such as a shortened service life of the refractory material when used at high temperatures. If it exceeds the above range, problems such as a manufacturing defect in the manufactured refractory material may occur.

[0032] The above resin can be manufactured by removing at least some of the hydrogens from the hydroxyl groups (-OH) at the terminal of the disaccharide to generate oxygen radicals (-O·), removing at least some of the hydroxyl groups (-OH) at the terminal of the carboxyl group of the citric acid to generate ketone radicals (-C(=O)·), and reacting the oxygen radicals at the terminal of the disaccharide with the ketone radicals at the terminal of the citric acid.

[0033]

[0034] The above binder composition may additionally contain magnesia. In this case, magnesia improves the adhesive strength of the binder composition, thereby enhancing the bonding strength between refractory aggregates when applied to refractory materials.

[0035] In addition, the binder composition may contain 1 to 20 parts by weight or 5 to 15 parts by weight of magnesia relative to 100 parts by weight of citric acid. If the content of magnesia relative to the content of citric acid in the binder composition is less than the above range, the bonding force between refractory aggregates may be insufficient, resulting in a problem of insufficient dry strength of the manufactured refractory. If it exceeds the above range, a problem may arise where sediment is formed or solidified in the binder composition, making it difficult to manufacture the binder.

[0036]

[0037] The above binder composition may additionally include an aqueous solvent. In this case, the aqueous solvent serves to generate the binder composition through dehydration, condensation reactions, etc. in an aqueous solution after dissolving the binder manufacturing raw material, and also to control the viscosity and fluidity of the composition.

[0038] Additionally, the aqueous solvent may be water, and specifically, may include at least one selected from the group consisting of ion-exchanged water, deionized water, pure water, ultrapure water, and distilled water.

[0039] The above-described binder for refractory materials is environmentally friendly because it does not emit aromatic organic compounds that are generated by thermal decomposition upon heating, which is a problem with conventional binders such as phenolic resins. In addition, while phenolic resins require a curing time of 3 to 24 hours after mixing, the binder for refractory materials according to the present invention can be molded immediately after mixing, resulting in excellent productivity. Furthermore, its excellent mixability allows for a shortened mixing time. Furthermore, while thermoplastic resins such as phenolic resins require heat treatment above a certain temperature to develop strength after molding, the binder for refractory materials according to the present invention is an aqueous binder, which can significantly shorten the drying time and save energy costs.

[0040]

[0041] fire refractory

[0042] The refractory material of the present invention includes a binder for refractory material as described above; and a refractory aggregate.

[0043] refractory aggregate

[0044] The above refractory aggregate may be used without any special limitation as long as it is commonly used as a raw material for refractories, and may include, for example, at least one selected from the group consisting of carbon-based, magnesia-based, alumina-based, chromium-based, and dolomite-based refractory aggregates. Specifically, the above refractory aggregate may include at least one selected from the group consisting of carbon-based, magnesia-alumina-carbon-based, alumina-magnesia-carbon-based, alumina-silicon carbide-carbon-based, and alumina-carbon-based; alumina-based, such as alumina-based and alumina-silicon-based; and chromium-based, such as magnesia-chromium-based.

[0045] The above refractory material may include 100 parts by weight of refractory aggregate and 0.5 to 5.0 parts by weight or 1.5 to 4.0 parts by weight of a binder for refractory material. If the content of the binder for refractory material relative to the content of the refractory aggregate is less than the above range, problems such as a decrease in the specific gravity of the manufactured refractory material, an increase in the porosity, or a decrease in the strength may occur, and if it exceeds the above range, problems such as a decrease in the productivity of the manufactured refractory material may occur.

[0046] As described above, the refractory material comprising the binder for refractory materials according to the present invention has excellent physical properties such as hot properties, strength, and erosion resistance, and thus can be applied to industrial fields that use high-temperature molten materials, such as iron and steel manufacturing. In particular, the refractory material has excellent refractory properties, and thus can be applied to various fields, such as electric furnaces, ladles, converters, torpedo cars, and refining processes such as iron and steel manufacturing.

[0047]

[0048] Method for manufacturing a binder for refractory materials

[0049] In addition, the method for manufacturing a binder for a refractory material according to the present invention includes a step of stirring and heating a binder composition including disaccharide, phosphoric acid, and citric acid.

[0050] For example, the method for manufacturing the above refractory binder

[0051] A step of preparing a first composition by mixing and dissolving citric acid in a water-soluble solvent;

[0052] A step of preparing a second composition by mixing the first composition and phosphoric acid; and

[0053] It may include a step of preparing a binder by mixing the second composition and the disaccharide to prepare a binder composition and then reacting the mixture by stirring and heating.

[0054] The above aqueous solvent may be water, and specifically, may include at least one selected from the group consisting of ion-exchanged water, deionized water, pure water, ultrapure water, and distilled water.

[0055] The above disaccharide may include at least one selected from the group consisting of sucrose, lactose, maltose, trehalose, cellobiose, and chitobiose. That is, the third unit may be a unit derived from at least one disaccharide selected from the group consisting of sucrose, lactose, maltose, trehalose, cellobiose, and chitobiose.

[0056] The binder composition may comprise 100 parts by weight of citric acid, 50 to 200 parts by weight of phosphoric acid, and 200 to 400 parts by weight of a disaccharide.

[0057] The above heating can be performed at 50 to 250°C or 100 to 200°C for 45 to 120 minutes or 60 to 90 minutes.

[0058] When the temperature is below the above range during heating, a problem occurs in which the amount of 5-(hydroxymethyl)furfural produced within the binder decreases, and when it exceeds the above range, a problem in which the binder solidifies may occur due to an insufficient amount of solvent within the binder, a decrease in concentration due to volatilization of 5-(hydroxymethyl)furfural, or an increase in the viscosity of the binder.

[0059] Meanwhile, if the treatment time during heating is less than the above range, problems such as insufficient production of 5-(hydroxymethyl)furfural in the manufactured binder or re-precipitation of disaccharides may occur, and if it exceeds the above range, the amount of solvent in the binder may be insufficient or the viscosity of the binder may increase, resulting in a solidification problem of the binder.

[0060] Additionally, the binder composition may further comprise magnesia.

[0061] Specifically, the method for manufacturing the above refractory binder is

[0062] A step of preparing a first composition by mixing and dissolving citric acid in a water-soluble solvent;

[0063] A step of preparing a second composition by mixing the first composition and magnesia, heating them for the first time, adding phosphoric acid, and mixing them; and

[0064] It may include a step of preparing a binder by mixing the second composition and the disaccharide to prepare a binder composition, and then reacting the mixture by stirring and secondary heating.

[0065] The above primary heating can be performed at 50 to 200°C or 80 to 150°C for 45 to 120 minutes or 60 to 90 minutes.

[0066] If the temperature is below the above range during the first heating, undissolved raw materials may remain in the binder, resulting in a problem of insufficient physical properties of the binder. If the temperature exceeds the above range, a problem may occur in which part of the binder evaporates and solidifies.

[0067] Meanwhile, if the processing time during the first heating is less than the above range, undissolved raw materials may remain in the binder, resulting in a problem of insufficient physical properties of the binder. If it exceeds the above range, a problem may arise where a portion of the binder evaporates and solidifies.

[0068] Additionally, the secondary heating can be performed at the temperature and processing time described above.

[0069]

[0070] Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are intended only to specifically illustrate specific embodiments of the present invention and are not intended to limit or restrict the scope of the present invention to the contents described in these examples.

[0071] Examples 1 to 11 and Comparative Examples 1 and 2. Preparation of binder for refractory material

[0072] A binder for refractory material was prepared using each component in the amounts described in Tables 1 and 2.

[0073] Specifically, a first composition was prepared by mixing water and citric acid and stirring until no sediment was formed. Magnesia was then added, heated to 100°C, and stirred until transparent. A second composition was prepared by adding phosphoric acid and stirring until transparent. Sucrose was then added, and heated to 140°C, producing a black-brown refractory binder.

[0074] Classification (weight part) Example 1234567 Water 400 400 400 400 400 400 400 Citric acid 200 200 200 200 200 200 Phosphoric acid 200 200 100 400 200 200 200 Sucrose 600-600 600 400 800 600 Maltose-600 --- Magnesia 181818181818-

[0075]

[0076] Classification (weight part) Comparative example Example 12891011 Water 400 400 400 400 400 400 Citric acid 200-200 200 200 200 Phosphoric acid-200 80 500 200 200 Sucrose 600 600 600 600 300 1,000 Magnesia 181818181818

[0077]

[0078] Experimental Example 1. Physical Property Measurement

[0079] 100 parts by weight of alumina-magnesia-carbon as refractory aggregate and 2.5 parts by weight of a binder for refractory materials of the examples or comparative examples were mixed, kneaded at 25 to 35°C for 15 minutes, molded into 230 mm X 180 mm X 80 mm (width X length X height), and dried at 200°C for 12 hours to manufacture a dried refractory. Thereafter, the dried refractory was fired at 1,000°C for 5 hours to manufacture a first fired refractory. In addition, the dried refractory was fired at 1,500°C for 5 hours to manufacture a second fired refractory. The physical properties of the dried refractory, the first fired refractory, and the second fired refractory thus manufactured were measured by the following methods, and the results are shown in Tables 3 and 4.

[0080] (1) Specific gravity after drying and specific gravity after firing

[0081] According to ISO 5017, refractory material was added to kerosene (impregnating liquid) and the specific gravity was calculated after drying or firing using the following mathematical formula 1. At this time, the specimen was manufactured to be 50 mm X 50 mm X 50 mm (width X length X height).

[0082] [Mathematical Formula 1]

[0083] ρ b (Specific gravity) = m1 / (m3-m2) X ρ liq

[0084] m1: Dry mass of refractory material (g)

[0085] m2: Apparent mass of impregnated refractory (g)

[0086] m3: Mass of impregnated specimen (g)

[0087] ρ liq : Density of impregnating liquid

[0088] (2) Porosity

[0089] According to ISO 5017, refractory material was added to kerosene (impregnating solution) and the porosity was calculated after drying or firing using the following mathematical formula 2. At this time, the specimen was manufactured to be 50 mm X 50 mm X 50 mm (width X length X height).

[0090] [Equation 2]

[0091] π a (Porosity) = (m3-m1) / (m3-m2) X 100

[0092] m1: Dry mass of refractory material (g)

[0093] m2: Mass of impregnated refractory material (g)

[0094] m3: Mass of impregnated specimen (g)

[0095] (3) Absorption rate

[0096] Absorption rate was measured according to ISO 5017.

[0097] (4) Compressive strength

[0098] The compressive strength of a refractory material measuring 50 mm X 50 mm X 50 mm (width X length X height) was measured using a hydraulic compressive strength tester according to the method described in KS L 3115.

[0099] (5) Hot flexural strength

[0100] According to ISO 5013:1985, the refractory material measuring 150mmX25mmX25mm (widthXlengthXheight) was measured using a rupture coefficient test device.

[0101]

[0102] Classification Example 1234567 Dry refractory specific gravity (g / cm) 3 )3.293.273.273.233.233.303.27Porosity (%)5.75.86.97.17.15.65.9Absorption (%)1.41.41.61.91.91.41.4Compressive strength (kgf / cm 2 )346342283343298309311Specific gravity of refractory material for first firing (g / cm) 3 )3.263.253.223.223.183.243.26Porosity (%)8.38.49.69.110.19.28.3Absorption (%)2.02.02.42.42.62.32.1Compressive strength (kgf / cm 2 )358358304310285313320Specific gravity of 2nd fired refractory material (g / cm) 3)3.193.193.103.053.153.183.17Porosity (%)10.210.211.314.811.010.411.3Absorption (%)2.52.53.13.92.92.62.7Compressive strength (kgf / cm 2 )324320300255280322309Hot bending strength (MPa)8.568.517.215.566.628.507.70

[0103]

[0104] Classification Comparison Example Example 12891011 Dry refractory specific gravity (g / cm) 3 )3.283.203.263.233.233.30Porosity (%)6.58.66.97.68.55.1Absorption (%)1.72.21.51.92.21.2Compressive strength (kgf / cm) 2 )239225253338228237Specific gravity of refractory material for first firing (g / cm) 3 )3.233.163.213.193.173.26Porosity (%)9.911.19.89.39.98.2Absorption (%)2.52.82.52.52.62.3Compressive strength (kgf / cm 2 )227234260286240232Specific gravity of 2nd fired refractory material (g / cm) 3 )3.173.023.113.043.153.18Porosity(%)10.614.811.515.311.410.0Absorption(%)2.63.93.03.92.82.4Compressive strength(kgf / cm 2 )295154254215251272Hot flexural strength (MPa)6.512.916.333.564.327.00

[0105]

[0106] As shown in Tables 3 and 4, the refractory material of the example had excellent molding specific gravity, post-drying properties, and post-sintering properties.

[0107] On the other hand, Comparative Example 1, which did not contain phosphoric acid, and Comparative Example 2, which did not contain citric acid, had insufficient compressive strengths of the dried refractory, the first-fired refractory, and the second-fired refractory. In particular, Comparative Example 2 had insufficient porosity of the refractory, and insufficient hot bending strength of the second-fired refractory.

[0108]

[0109] Experimental example 2.

[0110] GC-MS analysis of the refractory binder of Example 1 was performed, and the measurement conditions for GC-MS analysis were as follows, and the results are shown in Fig. 1 and Table 5.

[0111] Measurement instrument: Agilent 7890A 5975C GC-MS

[0112] Column: DB-5MS UI

[0113] Sample injection volume: 1 μl, Split ratio 10:1

[0114] Carrier gas: Helium (He), 1㎖ / min

[0115] Measurement molecular weight range: Scan mode (29 to 550 m / z)

[0116] [Table 5]

[0117]

[0118] As shown in Table 5 and Fig. 1, it was confirmed that the fire-resistant binder of Example 1 included a first unit derived from 5-(hydroxymethyl)furfural and a second unit derived from levoglucosan (beta-D-glucopyranose, 1,6-anhydro-).

Claims

A binder for a fire refractory, comprising a resin comprising a first unit derived from 5-(hydroxymethyl)furfural, a second unit derived from levoglucosan, and a third unit derived from a disaccharide; and phosphoric acid.

2. In claim 1, A binder for a fire refractory, wherein the resin comprises the first unit derived from 5-(hydroxymethyl)furfural in an amount of 10 to 60 wt% and the second unit derived from levoglucosan in an amount of 10 to 30 wt%, based on the total weight of the resin.

3. In claim 1, A binder for a fire refractory, wherein the disaccharide comprises at least one selected from the group consisting of sucrose, lactose, maltose, trehalose, cellobiose, and chitobiose.

4. In claim 1, A binder for refractory materials, prepared from a binder composition comprising disaccharides, phosphoric acid and citric acid.

5. In claim 4, A binder for a refractory material, wherein the binder composition comprises 100 parts by weight of citric acid, 50 to 200 parts by weight of phosphoric acid, and 200 to 400 parts by weight of a disaccharide.

6. In claim 4, A binder for refractory materials, wherein the binder composition further comprises magnesia.

7. In claim 6, A binder for refractory materials, wherein the binder composition comprises 1 to 20 parts by weight of magnesia per 100 parts by weight of citric acid.

8. A binder for a fire retardant according to any one of claims 1 to 7; and A refractory material comprising refractory aggregate.

9. In claim 8, The above refractory aggregate is a refractory material comprising at least one selected from the group consisting of carbon-based, magnesia-based, alumina-based, chromium-based, and dolomite-based refractory aggregates.

10. In claim 8, The above refractory aggregate is a refractory material comprising at least one carbon type selected from the group consisting of magnesia-carbon type, magnesia-alumina-carbon type, alumina-magnesia-carbon type, alumina-silicon carbide-carbon type, magnesia-chromium type, and alumina-carbon type.

11. In claim 8, A refractory comprising 100 parts by weight of refractory aggregate and 0.5 to 5.0 parts by weight of a binder for refractory.

12. A method for producing a binder for a refractory material, comprising the steps of stirring and heating a binder composition containing disaccharides, phosphoric acid and citric acid.

13. In claim 12, A step of preparing a first composition by mixing and dissolving citric acid in a water-soluble solvent; A step of preparing a second composition by mixing the first composition and citric acid; and A method for producing a binder for a refractory material, comprising: a step of producing a binder composition by mixing the second composition and the disaccharide, and then stirring and heating to react the binder.

14. In claim 12, A method for producing a binder for a refractory material, wherein the binder composition comprises 100 parts by weight of citric acid, 50 to 200 parts by weight of phosphoric acid, and 200 to 400 parts by weight of a disaccharide.

15. In claim 12, A method for producing a binder for refractory materials, wherein the above heating is performed at 50 to 250°C for 45 to 120 minutes.

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