A room-temperature stable / heat-hydrating micro-powder binder and its preparation method

Abstract

This invention relates to a room-temperature stable / heat-hydrating micronized binder and its preparation method. The technical solution is as follows: The organic polymer and organic solvent are mixed at a mass ratio of 1:20-40 to obtain an organic precursor modified solution; then, the micronized binder is added to the organic precursor modified solution at a mass ratio of 1:0.5-2, and stirred for the first time to obtain a micronized binder suspension; then, a precipitant is added to the micronized binder suspension at a mass ratio of 1:2-5, and stirred for the second time to obtain a modified micronized binder suspension; the modified micronized binder suspension is subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrating micronized binder. The product prepared by this invention exhibits good fluidity, high room-temperature flexural strength, high high-temperature flexural strength, and excellent resistance to slag erosion when used in the preparation of castables.

Description

Technical Field

[0001] This invention belongs to the field of micronized powder binder technology. Specifically, it relates to a micronized powder binder that is stable at room temperature / hydrates upon heating and its preparation method. Background Technology

[0002] Binders are a crucial component of refractory castables, primarily categorized into cement binders, chemical binders, and micronized binders. Among these, refractory castables prepared using micronized binders (highly active magnesium oxide and hydrated alumina) exhibit excellent mechanical and erosion resistance properties, making them a major research focus in the development of high-performance refractory castables. However, micronized binders suffer from rapid hydration in refractory castables. During the room-temperature mixing stage, the hydration reaction consumes a significant amount of water in the system, leading to a sharp decrease in the fluidity of the refractory castable (or a sharp increase in water addition), failing to meet construction requirements. Therefore, inhibiting the hydration of micronized binders has attracted widespread attention from researchers. For example:

[0003] 1) The patented technology "A Magnesium Binder Using Used Refractory Material as Raw Material and Its Application" (CN113149669A) uses organic acids (citric acid, acrylic acid, and oxalic acid, etc.) to inhibit the hydration of magnesium oxide. The magnesium oxide used is obtained from used magnesium refractory material through screening, crushing, and fine grinding. This magnesium oxide has almost no activity and hydrates relatively slowly in water. Although the castables prepared with it as a binder have improved thermal shock resistance and erosion resistance, the room temperature flexural strength of the castables after heat treatment is low, which limits its application in actual production.

[0004] 2) The patented technology of “A magnesium binder and a method for preparing refractory materials using a magnesium binder” (CN112321306A) uses magnesium oleate and methylmalonic acid to inhibit the hydration of light-burned magnesium oxide and changes the morphology of the hydration products to improve the strength of the castable. However, the light-burned magnesium oxide used has low activity, and the strength of the castable is not significantly improved after inhibiting hydration. Moreover, if this method is applied to high-activity magnesium oxide with higher activity, it cannot solve the problem of poor fluidity of the castable.

[0005] 3) The authors of Reference I (Zhang Yu. Formation of hydrated magnesium silicate in magnesia castables and its influence on material properties [D]. Wuhan University of Science and Technology, 2018) used hydrated magnesium silicate, a colloidal compound formed by the reaction of silica and magnesium oxide. Due to its slow removal of structural water, it has been widely used in magnesia castable systems. However, at room temperature, the slow formation rate of hydrated magnesium silicate affects the workability of the castable; moreover, the silica in this system forms a liquid phase at high temperatures, which negatively impacts the slag resistance and high-temperature mechanical properties of the castable. In addition, hydrated magnesium silicate is a magnesium-based cementitious compound, which has good adaptability to magnesia or magnesia-alumina refractory castables, but its application in other castable systems is limited.

[0006] 4) The authors of Reference II (Dos Santos T, Pinola FG, Luz AP, et al. Al2O3-MgO refractorycastables with enhanced explosion resistance due to in situ formation of phases with lamellar structure[J]. Ceramics International, 2018, 44(7): 8048-8056) used formic acid to inhibit the hydration of dead-burned magnesia, successfully suppressing the formation of cracks in dead-burned magnesia-bonded refractory castables and improving the dry strength of the castables. However, the active magnesia-bonded refractory castables, as a contrast, still produced a large number of cracks. Due to the low activity of dead-burned magnesia, the hydration rate is relatively slow, and fewer hydration products are generated, resulting in lower dry strength of the castables; while the active magnesia has high activity and a too fast hydration rate, formic acid cannot regulate the nucleation process of magnesium hydroxide on its surface, resulting in decreased fluidity of the castables and failure to meet construction requirements.

[0007] 5) The authors of Reference III (Luz AP, Consoni LB, Pagliosa C, et al. MgO fumes as a potential binder for in situ spinel containing refractory castables[J]. Ceramics International, 2018, 44(13): 15453-15463) used formic acid and aluminum lactate to inhibit the hydration of magnesium oxide flue gas. This magnesium oxide is an extremely fine magnesium oxide powder obtained during the production of fused magnesium oxide, and its activity is higher than that of dead-burned magnesium oxide. Through the regulation of formic acid and aluminum lactate, the demolding strength and drying strength of the refractory castable bound by magnesium oxide flue gas were improved. However, compared with active magnesium oxide, the activity of magnesium oxide flue gas is still low, and its effect on improving the strength of the castable is not obvious.

[0008] In summary, the shortcomings of the existing technology are: the low activity of the micronized binder has no significant effect on improving the strength of the castable, and the higher activity of the micronized binder cannot inhibit hydration; the micronized binder used in castables has poor fluidity, low flexural strength at room temperature, low flexural strength at high temperature, and poor resistance to slag erosion. Summary of the Invention

[0009] The present invention aims to overcome the technical defects existing in the prior art, and aims to provide a room-temperature stable / heat-heat hydration micro powder binder and its preparation method that is simple to process, suitable for industrial production and hydration control, and has higher activity. The room-temperature stable / heat-heat hydration micro powder binder is used to prepare castables with good fluidity, high room-temperature flexural strength, high high-temperature flexural strength and excellent slag erosion resistance.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] The organic polymer and organic solvent are mixed at a mass ratio of 1:20-40 to obtain an organic precursor modification solution. Then, the micronized binder is added to the organic precursor modification solution at a mass ratio of 1:0.5-2, and the mixture is stirred for the first time to obtain a micronized binder suspension. Next, a precipitant is added to the micronized binder suspension at a mass ratio of 1:2-5, and the mixture is stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension is then subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0012] The organic polymer is one of polyacrylamide coacrylonitrile, polyN-acrylamide glycinamide, poloxamer, polyvinyl alcohol, and polyethylene; the organic polymer is of industrial purity or analytical purity.

[0013] The organic solvent is one of dimethyl sulfoxide, acetone, diethyl ether, and toluene; the organic solvent is industrially pure or analytically pure.

[0014] The micro powder binder is active magnesium oxide or hydrated aluminum oxide; the micro powder binder is industrially pure or analytically pure; the particle size of the micro powder binder is ≤0.044mm.

[0015] The first stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 2-5 hours.

[0016] The precipitant is methanol or ethanol; the precipitant is industrially pure or analytically pure.

[0017] The second stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 0.1-0.2 hours.

[0018] The solid-liquid separation is performed by centrifugation at 8000–12000 rpm for 5–20 minutes.

[0019] The drying conditions are: a drying temperature of 80–110°C and a drying time of 12–48 hours.

[0020] Due to the adoption of the above technical solution, the beneficial effects of this invention compared with the prior art are as follows:

[0021] 1. The room-temperature stable / heat-heat hydrating micro-powder binder provided by this invention has a temperature-sensitive modified layer on its surface during the room-temperature mixing and casting stages of refractory castables. This modified layer is insoluble in water at room temperature, separating the water from the micro-powder binder. Therefore, the micro-powder binder does not hydrate during this stage, maintaining stability during the mixing and casting stages of refractory castables, improving the fluidity of the castable, and meeting construction requirements. Subsequently, during the curing stage (temperature is generally 50-80℃), the modified layer dissolves in water. At this time, the micro-powder binder reacts with water, fully hydrating to form a bound phase, improving the room-temperature flexural strength of the refractory castable.

[0022] 2. The room-temperature stable / heat-heat hydrating micro powder binder provided by this invention is uniformly hydrated in refractory castables. The hydrated binder has fine grains and is more likely to react with other components to form high-temperature binders such as magnesium aluminum spinel during the high-temperature treatment stage. This can significantly improve the high-temperature flexural strength and slag erosion resistance of refractory castables.

[0023] 3. In this invention, an organic precursor modification solution is prepared by mixing organic polymers and organic solvents. Then, a micronized binder is added to the organic precursor modification solution, stirred thoroughly, a precipitant is added, and the mixture is centrifuged. After drying and grinding, a room-temperature stable / heat-hydrated micronized binder is obtained. The preparation process is simple and suitable for industrial production.

[0024] Therefore, the present invention has the characteristics of simple process, suitable for industrial production and hydration control, and higher activity. The micro powder binder obtained by room temperature stable / heating hydration has good fluidity, high room temperature flexural strength, high high temperature flexural strength and excellent slag erosion resistance when used to prepare castables. Attached Figure Description

[0025] Figure 1 The table shows the pH change over time at 25℃ and 60℃ for a room-temperature stable / heat-increasing hydrated micro-powder binder prepared according to the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of protection thereof.

[0027] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0028] The organic polymer and organic solvent are mixed at a mass ratio of 1:20-40 to obtain an organic precursor modification solution. Then, the micronized binder is added to the organic precursor modification solution at a mass ratio of 1:0.5-2, and the mixture is stirred for the first time to obtain a micronized binder suspension. Next, a precipitant is added to the micronized binder suspension at a mass ratio of 1:2-5, and the mixture is stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension is then subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0029] The organic polymer is one of polyacrylamide coacrylonitrile, polyN-acrylamide glycinamide, poloxamer, polyvinyl alcohol, and polyethylene; the organic polymer is of industrial purity or analytical purity.

[0030] The organic solvent is one of dimethyl sulfoxide, acetone, diethyl ether, and toluene; the organic solvent is industrially pure or analytically pure.

[0031] The micro powder binder is active magnesium oxide or hydrated aluminum oxide; the micro powder binder is industrially pure or analytically pure.

[0032] The first stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 2-5 hours.

[0033] The precipitant is methanol or ethanol; the precipitant is industrially pure or analytically pure.

[0034] The second stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 0.1-0.2 hours.

[0035] The solid-liquid separation is performed by centrifugation at 8000–12000 rpm for 5–20 minutes.

[0036] The drying conditions are: a drying temperature of 80–110°C and a drying time of 12–48 hours.

[0037] In this specific implementation:

[0038] The particle size of the micro powder binder is ≤0.044mm.

[0039] In this specific implementation: the pH value is determined by adding 2g of room-temperature stable / heat-hydrated micro-powder binder to 100ml of water and measuring its change over 600 seconds using a pH meter; when the room-temperature stable / heat-hydrated micro-powder binder reacts with water to generate hydration products, the OH- in the water... - This will increase, leading to an increase in pH value.

[0040] In this specific implementation: the refractory castable is prepared according to national standards GB / T 4513.5 and GB / T 4513.6, and its components include tabular corundum aggregate (69wt%), tabular corundum fine powder (20wt%), α-alumina micro powder (6wt%), and micro powder binder (5wt%), with a water content of 5wt%. The flow value of the refractory castable is tested according to GB / T 4513.4-2017. The demolding strength of the refractory castable is tested according to GB / T 3001-2017.

[0041] The details will not be repeated in the examples.

[0042] Example 1

[0043] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0044] The organic polymer and organic solvent were mixed at a mass ratio of 1:20 to obtain an organic precursor modification solution. Then, the micronized binder was added to the organic precursor modification solution at a mass ratio of 1:0.5, and the mixture was stirred for the first time to obtain a micronized binder suspension. Next, a precipitant was added to the micronized binder suspension at a mass ratio of 1:2, and the mixture was stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension was subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0045] The organic polymer is polyacrylonitrile coacrylonitrile; the organic polymer is of industrial purity.

[0046] The organic solvent is dimethyl sulfoxide; the organic solvent is of industrial purity.

[0047] The micro powder binder is active magnesium oxide; the micro powder binder is industrially pure or analytically pure.

[0048] The first stirring was carried out at a speed of 400 rpm and a temperature of 20°C for 2 hours.

[0049] The precipitant is methanol; the precipitant is industrially pure.

[0050] The second stirring was carried out at a speed of 400 rpm and a temperature of 20°C for 0.1 hours.

[0051] The solid-liquid separation was performed by centrifugation at 8000 rpm for 5 minutes.

[0052] The drying conditions are: a drying temperature of 110°C and a drying time of 12 hours.

[0053] The room-temperature stable / heat-hydrating micro-powder binder prepared in this example is, for example, Figure 1 As shown, Figure 1 This table shows the pH change over time of the room-temperature stable / heat-increasing hydrated micronized binder prepared in Example 1 at 25°C and 60°C. Figure 1 It can be seen that the pH value increased from 6.3 to 7.0 at 25℃, while it increased from 6.4 to 10.0 at 60℃.

[0054] The performance of refractory castables prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: flowability value is 105%; demolding flexural strength after curing at 60℃ is 4.45 MPa.

[0055] Example 2

[0056] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0057] The organic polymer and organic solvent were mixed at a mass ratio of 1:25 to obtain an organic precursor modification solution. Then, the micronized binder was added to the organic precursor modification solution at a mass ratio of 1:1, and the mixture was stirred for the first time to obtain a micronized binder suspension. Next, a precipitant was added to the micronized binder suspension at a mass ratio of 1:4, and the mixture was stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension was subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0058] The organic polymer is poly-N-acrylamide; the organic polymer is of analytical grade.

[0059] The organic solvent is acetone; the organic solvent is of analytical grade.

[0060] The micro powder binder is active magnesium oxide; the micro powder binder is of analytical grade.

[0061] The first stirring was carried out at a speed of 500 rpm and a temperature of 25°C for 4 hours.

[0062] The precipitant is methanol; the precipitant is of analytical grade.

[0063] The second stirring was carried out at a speed of 500 rpm and a temperature of 25°C for 0.2 hours.

[0064] The solid-liquid separation was performed by centrifugation at 12,000 rpm for 10 minutes.

[0065] The drying conditions are: a drying temperature of 100°C and a drying time of 24 hours.

[0066] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.1 to 7.2 at 25°C, and an increase in pH value from 6.3 to 10.1 at 60°C.

[0067] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 107%; the demolding flexural strength after curing at 60℃ is 4.37 MPa.

[0068] Example 3

[0069] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0070] The organic polymer and organic solvent were mixed at a mass ratio of 1:30 to obtain an organic precursor modification solution. Then, the micronized binder was added to the organic precursor modification solution at a mass ratio of 1:1.5, and the mixture was stirred for the first time to obtain a micronized binder suspension. Next, a precipitant was added to the micronized binder suspension at a mass ratio of 1:3, and the mixture was stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension was subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0071] The organic polymer is poloxamer; the organic polymer is of industrial purity.

[0072] The organic solvent is diethyl ether; the organic solvent is of industrial purity.

[0073] The micro powder binder is active magnesium oxide, and the micro powder binder is of industrial purity.

[0074] The first stirring was carried out at a speed of 600 rpm and a temperature of 30°C for 3.5 hours.

[0075] The precipitant is ethanol; the precipitant is of industrial purity.

[0076] The second stirring was carried out at a speed of 600 rpm and a temperature of 30°C for 0.1 hours.

[0077] The solid-liquid separation was performed by centrifugation at 10,000 rpm for 15 minutes.

[0078] The drying conditions are: a drying temperature of 80°C and a drying time of 48 hours.

[0079] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.2 to 7.1 at 25°C, and an increase in pH value from 6.3 to 10.2 at 60°C.

[0080] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrated micro-powder binder obtained in this example is as follows: the flow value is 102%; the demolding flexural strength after curing at 60℃ is 4.32 MPa.

[0081] Example 4

[0082] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0083] The organic polymer and organic solvent were mixed at a mass ratio of 1:35 to obtain an organic precursor modification solution. Then, the micronized binder was added to the organic precursor modification solution at a mass ratio of 1:2, and the mixture was stirred for the first time to obtain a micronized binder suspension. Next, a precipitant was added to the micronized binder suspension at a mass ratio of 1:5, and the mixture was stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension was subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0084] The organic polymer is polyvinyl alcohol; the organic polymer is of analytical grade.

[0085] The organic solvent is toluene; the organic solvent is of analytical grade.

[0086] The micro powder binder is active magnesium oxide; the micro powder binder is of analytical grade.

[0087] The first stirring was carried out at a speed of 700 rpm and a temperature of 25°C for 5 hours.

[0088] The precipitant is ethanol; the precipitant is of analytical grade.

[0089] The second stirring was carried out at a speed of 700 rpm and a temperature of 25°C for 0.15 hours.

[0090] The solid-liquid separation was performed by centrifugation at 9000 rpm for 20 minutes.

[0091] The drying conditions are: a drying temperature of 90°C and a drying time of 36 hours.

[0092] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.4 to 7.0 at 25°C, and an increase in pH value from 6.1 to 10.1 at 60°C.

[0093] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 100%; the demolding flexural strength after curing at 60℃ is 4.35MPa.

[0094] Example 5

[0095] A room-temperature stable / heat-hydrating micro-powder binder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0096] The organic polymer and organic solvent were mixed at a mass ratio of 1:40 to obtain an organic precursor modification solution. Then, the micronized binder was added to the organic precursor modification solution at a mass ratio of 1:0.5, and the mixture was stirred for the first time to obtain a micronized binder suspension. Next, a precipitant was added to the micronized binder suspension at a mass ratio of 1:3.5, and the mixture was stirred for the second time to obtain a modified micronized binder suspension. The modified micronized binder suspension was subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micronized binder.

[0097] The organic polymer is polyethylene; the organic polymer is of industrial purity.

[0098] The organic solvent is dimethyl sulfoxide; the organic solvent is of industrial purity.

[0099] The micro powder binder is active magnesium oxide; the micro powder binder is industrially pure.

[0100] The first stirring was carried out at a speed of 800 rpm and a temperature of 30°C for 3 hours.

[0101] The precipitant is ethanol; the precipitant is of industrial purity.

[0102] The second stirring was carried out at a speed of 800 rpm and a temperature of 30°C for 0.2 hours.

[0103] The solid-liquid separation was performed by centrifugation at 11,000 rpm for 20 minutes.

[0104] The drying conditions are: a drying temperature of 110°C and a drying time of 12 hours.

[0105] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.0 to 7.1 at 25°C, and an increase in pH value from 6.3 to 10.3 at 60°C.

[0106] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 101%; the demolding flexural strength after curing at 60℃ is 4.29 MPa.

[0107] Example 6

[0108] A room-temperature stable / heat-hydrating micronized powder binder and its preparation method. Except for the micronized powder binder, this embodiment is the same as in Example 1:

[0109] The micro powder binder is hydrated alumina.

[0110] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.3 to 7.0 at 25°C, and an increase in pH value from 6.2 to 10.0 at 60°C.

[0111] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 110%; the demolding flexural strength after curing at 60℃ is 3.71 MPa.

[0112] Example 7

[0113] A room-temperature stable / heat-hydrating micronized powder binder and its preparation method. Except for the micronized powder binder, this embodiment is the same as Example 2.

[0114] The micro powder binder is hydrated alumina.

[0115] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.2 to 7.2 at 25°C, and an increase in pH value from 6.2 to 10.1 at 60°C.

[0116] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrated micro-powder binder obtained in this example is as follows: the flow value is 112%; the demolding flexural strength after curing at 60℃ is 3.75MPa.

[0117] Example 8

[0118] A room-temperature stable / heat-hydrating micronized powder binder and its preparation method. Except for the micronized powder binder, this embodiment is the same as in Example 3.

[0119] The micro powder binder is hydrated alumina.

[0120] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.3 to 7.1 at 25°C, and an increase in pH value from 6.3 to 10.1 at 60°C.

[0121] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 115%; the demolding flexural strength after curing at 60℃ is 3.79 MPa.

[0122] Example 9

[0123] A room-temperature stable / heat-hydrating micronized powder binder and its preparation method. Except for the micronized powder binder, this embodiment is the same as Example 4.

[0124] The micro powder binder is hydrated alumina.

[0125] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.1 to 7.0 at 25°C, and an increase in pH value from 6.0 to 10.1 at 60°C.

[0126] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 113%; the demolding flexural strength after curing at 60℃ is 3.82 MPa.

[0127] Example 10

[0128] A room-temperature stable / heat-hydrating micronized powder binder and its preparation method. Except for the micronized powder binder, this embodiment is the same as Example 5.

[0129] The micro powder binder is hydrated alumina.

[0130] The room-temperature stable / heat-increasing hydrated micronized binder prepared in this example showed an increase in pH value from 6.2 to 7.4 at 25°C, and an increase in pH value from 6.1 to 10.3 at 60°C.

[0131] The performance of the refractory castable prepared using the room-temperature stable / heat-heat hydrating micro-powder binder obtained in this example is as follows: the flow value is 114%; the demolding flexural strength after curing at 60℃ is 3.78MPa.

[0132] Comparative Example 1

[0133] A room-temperature stable / heat-hydrating micronized binder and its preparation method. This comparative example is identical to Example 1 except that no organic polymer is added.

[0134] The room-temperature stable / heat-increasing hydrated micro-powder binder prepared in this comparative example showed an increase in pH value from 6.2 to 10.6 at 25°C and an increase in pH value from 6.1 to 10.8 at 60°C.

[0135] The performance of refractory castable prepared using the room-temperature stable / heat-heat hydrated micro-powder binder obtained in this comparative example is as follows: flow value is 35%; demolding flexural strength after curing at 60℃ is 2.13 MPa.

[0136] Comparative Example 2

[0137] A room-temperature stable / heat-hydrating micronized binder and its preparation method. This comparative example is identical to Example 6 except that no organic polymer is added.

[0138] The room-temperature stable / heat-increasing hydrated micro-powder binder prepared in this comparative example showed an increase in pH value from 6.3 to 10.5 at 25°C and an increase in pH value from 6.4 to 10.4 at 60°C.

[0139] The performance of refractory castables prepared using the room-temperature stable / heat-heat hydrated micro-powder binder obtained in this comparative example is as follows: flow value is 70%; demolding flexural strength after curing at 60℃ is 1.81 MPa.

[0140] The advantages of this invention compared to the prior art are as follows:

[0141] 1. The room-temperature stable / heat-heat hydrating micro-powder binder provided by this invention has a temperature-sensitive modified layer on its surface during the room-temperature mixing and casting stages of refractory castables. This modified layer is insoluble in water at room temperature, separating the water from the micro-powder binder. Therefore, the micro-powder binder does not hydrate during this stage, maintaining stability during the mixing and casting stages of refractory castables, improving the fluidity of the castable, and meeting construction requirements. Subsequently, during the curing stage (temperature is generally 50-80℃), the modified layer dissolves in water. At this time, the micro-powder binder reacts with water, fully hydrating to form a bound phase, improving the room-temperature flexural strength of the refractory castable.

[0142] 2. The room-temperature stable / heat-heat hydrating micro powder binder provided by this invention is uniformly hydrated in refractory castables. The hydrated binder has fine grains and is more likely to react with other components to form high-temperature binders such as magnesium aluminum spinel during the high-temperature treatment stage. This can significantly improve the high-temperature flexural strength and slag erosion resistance of refractory castables.

[0143] 3. In this invention, an organic precursor modification solution is prepared by mixing organic polymers and organic solvents. Then, a micronized binder is added to the organic precursor modification solution, stirred thoroughly, a precipitant is added, and the mixture is centrifuged. After drying and grinding, a room-temperature stable / heat-hydrated micronized binder is obtained. The preparation process is simple and suitable for industrial production.

[0144] The room-temperature stable / heat-increasing hydrated micro-powder binder prepared in this specific embodiment was tested and found to have a pH value that increased from 6.0-6.4 to 7.0-7.4 at 25°C and from 6.0-6.4 to 10.0-10.3 at 60°C. In contrast, the room-temperature stable / heat-increasing hydrated micro-powder binders prepared in Comparative Examples 1 and 2 had pH values ​​that increased from 6.2 and 6.3 to 10.5 and 10.6 at 25°C and from 6.1 and 6.4 to 10.4 and 10.8 at 60°C.

[0145] The performance of refractory castables prepared using the room-temperature stable / heat-heat hydrated micro-powder binder obtained in this example was tested: the flow value was 100-115%; the demolding flexural strength after curing at 60℃ was 3.71-4.45 MPa; while the performance of refractory castables prepared using the room-temperature stable / heat-heat hydrated micro-powder binders prepared in Comparative Examples 1 and 2 was: the flow value was 35% and 70% respectively; the demolding flexural strength after curing at 60℃ was 1.81 MPa and 2.13 MPa respectively.

[0146] Therefore, the present invention has the characteristics of simple process, suitable for industrial production and hydration control, and higher activity. The micro powder binder obtained by room temperature stable / heating hydration has good fluidity, high room temperature flexural strength, high high temperature flexural strength and excellent slag erosion resistance when used to prepare castables.

Claims

1. A method for preparing a room-temperature stable / heat-hydrating micro-powder binder, characterized in that, The organic polymer and organic solvent are mixed at a mass ratio of 1:20~40 to obtain an organic precursor modification solution. Then, the micro-powder binder is added to the organic precursor modification solution at a mass ratio of 1:0.5~2, and the mixture is stirred for the first time to obtain a micro-powder binder suspension. Next, a precipitant is added to the micro-powder binder suspension at a mass ratio of 1:2~5, and the mixture is stirred for the second time to obtain a modified micro-powder binder suspension. The modified micro-powder binder suspension is then subjected to solid-liquid separation, dried, and ground to obtain a room-temperature stable / heat-hydrated micro-powder binder. The organic polymer is one of polyacrylamide coacrylonitrile, polyN-acrylamide glycinamide, poloxamer, polyvinyl alcohol, and polyethylene; the organic polymer is of industrial purity or analytical purity.

2. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The organic solvent is one of dimethyl sulfoxide, acetone, diethyl ether, and toluene; the organic solvent is industrially pure or analytically pure.

3. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The micro powder binder is active magnesium oxide or hydrated aluminum oxide; the micro powder binder is industrially pure or analytically pure; the particle size of the micro powder binder is ≤0.044mm.

4. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The first stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 2-5 hours.

5. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The precipitant is methanol or ethanol; the precipitant is industrially pure or analytically pure.

6. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The second stirring is carried out at a speed of 400-800 rpm and a temperature of 20-30°C for 0.1-0.2 hours.

7. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The solid-liquid separation is performed by centrifugation at 8000~12000 rpm for 5~20 minutes.

8. The preparation method of the room-temperature stable / heat-increasing hydration micro-powder binder according to claim 1, characterized in that, The drying conditions are: drying temperature of 80~110℃; drying time of 12~48 hours.

9. A micro-powder binder that is stable at room temperature / hydrates upon heating, characterized in that... The room-temperature stable / heat-increasing hydration micro-powder binder is prepared by the method for preparing the room-temperature stable / heat-increasing hydration micro-powder binder according to any one of claims 1 to 8.

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