Magnesium-manganese-aluminum composite spinel refractory material and preparation method thereof

Abstract

The application provides a magnesium-manganese-aluminum composite spinel refractory material and a preparation method thereof, and belongs to the technical field of refractory materials.The magnesium-manganese-aluminum composite spinel refractory material is prepared from raw materials including the following components in parts by mass: magnesia 40-120 parts, iron-aluminum spinel 1-20 parts, alpha-Al2O3 micro powder 1-5 parts, manganese dioxide powder 0.1-2 parts, manganese powder 0.1-2 parts, a binding agent 1-5 parts, an additive 0.1-1 part, calcium hexaluminate 10-20 parts and fibers 5-15 parts; the fibers are titanium dioxide-coated aluminum silicate fibers; and the additive is nano zirconium oxide and nano titanium oxide.The additive and the calcium hexaluminate can synergistically reduce the thermal conductivity; the fibers have a low thermal conductivity, so that the internal structure of the refractory material is more compact, and the strength is significantly improved; the aluminum silicate fibers have excellent thermal stability and chemical stability, so that the hanging kiln skin performance and the corrosion resistance are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory materials, and particularly relates to a magnesium-manganese-aluminum composite spinel refractory material and a preparation method thereof. BACKGROUND

[0002] The magnesium-manganese-aluminum spinel refractory material is a high-performance refractory material mainly formed of oxides of magnesium, manganese and aluminum in a spinel structure. The material is widely used in cement kilns, steel smelting and other high-temperature industrial fields due to its excellent high-temperature performance and thermal shock resistance. However, with the development of the industrial field, the current magnesium-manganese-aluminum spinel refractory material cannot meet the use requirements, and has problems of high thermal conductivity, low strength, low kiln skin hanging performance and low corrosion resistance. Therefore, how to reduce the thermal conductivity of the magnesium-manganese-aluminum spinel refractory material and improve the strength, kiln skin hanging performance and corrosion resistance has become a difficult problem to be solved in the field. SUMMARY

[0003] The application aims to provide a magnesium-manganese-aluminum composite spinel refractory material and a preparation method thereof. The magnesium-manganese-aluminum composite spinel refractory material provided by the application has excellent strength, kiln skin hanging performance, corrosion resistance and low thermal conductivity.

[0004] In order to achieve the above application purposes, the application provides the following technical solutions.

[0005] The application provides a magnesium-manganese-aluminum composite spinel refractory material prepared from raw materials including the following mass fractions:

[0006] 40-120 parts of magnesia, 1-20 parts of hercynite, 1-5 parts of alpha-Al2O3 micro powder, 0.1-2 parts of manganese dioxide powder, 0.1-2 parts of manganese powder, 1-5 parts of a binding agent, 0.1-1 part of an additive, 10-20 parts of calcium hexaluminate and 5-15 parts of fibers;

[0007] The fibers are titanium dioxide-coated aluminum silicate fibers.

[0008] The additive is nano-zirconium oxide and nano-titanium oxide.

[0009] Preferably, the magnesium-manganese-aluminum composite spinel refractory material is prepared from raw materials including the following mass percentages:

[0010] 50-100 parts of magnesia, 5-15 parts of hercynite, 2-4 parts of alpha-Al2O3 micro powder, 0.5-1.5 parts of manganese dioxide powder, 0.5-1.5 parts of manganese powder, 2-4 parts of a binding agent, 0.2-0.9 part of an additive, 12-18 parts of calcium hexaluminate and 8-12 parts of fibers.

[0011] Preferably, the mass ratio of the nano-zirconium oxide and the nano-titanium oxide is 1: (1-5).

[0012] Preferably, the particle size of the α-Al2O3 micro powder is 400-600 mesh.

[0013] Preferably, the particle size of the manganese dioxide powder is 300-500 mesh.

[0014] Preferably, the mass ratio of the additive and calcium hexaluminate is 1: (10-20).

[0015] Preferably, the mass ratio of the additive and calcium hexaluminate is 1: (14-16).

[0016] The application also provides a preparation method of the magnesium-manganese-aluminum composite spinel refractory material, comprising the following steps:

[0017] (1) mixing magnesite, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additive, calcium hexaluminate and fiber to obtain a mixture;

[0018] (2) forming the mixture obtained in step (1) to obtain a blank;

[0019] (3) sintering the blank obtained in step (2) to obtain the magnesium-manganese-aluminum composite spinel refractory material.

[0020] Preferably, the pressure for forming in step (2) is 10-15 kN / cm 2 .

[0021] Preferably, the sintering temperature in step (3) is 1000-1300 ℃, and the sintering time is 5-12 h.

[0022] The application provides a magnesium-manganese-aluminum composite spinel refractory material, which is prepared from raw materials including the following components in parts by mass: magnesia 40-120 parts, hercynite 1-20 parts, alpha-Al2O3 micro powder 1-5 parts, manganese dioxide powder 0.1-2 parts, manganese powder 0.1-2 parts, binder 1-5 parts, additive 0.1-1 part, calcium hexaluminate 10-20 parts and fiber 5-15 parts; the fiber is titanium dioxide-coated aluminum silicate fiber; and the additive is nano zirconium oxide and nano titanium oxide. The additive and the calcium hexaluminate can synergistically reduce the thermal conductivity; the additive can accelerate the grain boundary diffusion, and close the pores in the grain, thereby reducing the thermal conductivity; the calcium hexaluminate has low thermal conductivity and excellent chemical corrosion resistance, and can effectively improve the corrosion resistance and reduce the thermal conductivity; the fiber has low thermal conductivity, and can reduce the thermal conductivity; as a sintering aid, the fiber can promote the sintering of the spinel, make the internal structure of the refractory material more compact, and significantly improve the strength; in addition, the aluminum silicate fiber has excellent thermal stability and chemical stability, and can improve the hanging kiln skin performance and corrosion resistance. Experimental results show that the magnesium-manganese-aluminum composite spinel refractory material provided by the application has a bulk density of 2.98-3.00 g / cm 3 , an apparent porosity of 15.3-16.2%, a cold compressive strength of 65-75 MPa, a thermal conductivity (1000 DEG C) of 2.439-2.840 W / m·K, a corrosion resistance of 12-18%, and a hanging kiln skin performance of 20.54-25.09 MPa. DETAILED DESCRIPTION

[0023] The application provides a magnesium-manganese-aluminum composite spinel refractory material, which is prepared from raw materials including the following components in parts by mass:

[0024] magnesia 40-120 parts, hercynite 1-20 parts, alpha-Al2O3 micro powder 1-5 parts, manganese dioxide powder 0.1-2 parts, manganese powder 0.1-2 parts, binder 1-5 parts, additive 0.1-1 part, calcium hexaluminate 10-20 parts and fiber 5-15 parts;

[0025] The fiber is titanium dioxide-coated aluminum silicate fiber.

[0026] The additive is nano zirconium oxide and nano titanium oxide.

[0027] The application does not have special limitations on the sources of the raw materials, and commercially available products known to those skilled in the art can be used.

[0028] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the present application includes 40-120 parts of magnesia in terms of mass fraction. As an embodiment, the mass fraction of the magnesia can be 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts or 110 parts. In the present application, the content of the magnesia is controlled to cooperate with other ingredients to ensure the mineral stability and volume stability of the refractory material, thereby improving the mechanical flexibility of the refractory material.

[0029] In the present application, the magnesia preferably includes magnesia particles and magnesia fine powder; the particle size of the magnesia particles is preferably 3-5 mm; the particle size of the magnesia fine powder is preferably less than 0.063 mm; and the mass ratio of the magnesia particles to the magnesia fine powder is preferably (1-5):1. In the present application, the content of the magnesia is controlled to cooperate with other ingredients to ensure the mineral stability and volume stability of the refractory material, thereby improving the mechanical flexibility of the refractory material; the mass ratio of the magnesia particles to the magnesia fine powder is controlled to further improve the compressive strength of the refractory material; the magnesia particles serve as a framework, and the magnesia fine powder fills the gaps, thereby improving the compactness of the refractory material and further improving the compressive strength of the refractory material.

[0030] As an embodiment, the mass ratio of the magnesia particles to the magnesia fine powder can be 2:1, 3:1 or 4:1.

[0031] In the present application, the magnesia preferably includes fused magnesia and / or sintered magnesia; and the mass percentage content of MgO in the magnesia is preferably ≥96%.

[0032] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the present application includes 1-20 parts of hercynite in terms of mass fraction of the magnesia (40-120 parts). As an embodiment, the mass fraction of the hercynite can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts or 19 parts. In the present application, the iron ions in the hercynite diffuse into the magnesia, thereby improving the hanging kiln skin performance of the refractory material; in addition, the hercynite can also react with the magnesia, thereby improving the strength of the refractory material.

[0033] In the present application, the particle size of the hercynite is preferably 1-3 mm.

[0034] As an embodiment, the chemical composition of the hercynite can include Fe2O340.22%, SiO21.32%, Al2O355.81% and CaO 2.65% in terms of mass percentage.

[0035] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the present application comprises 1-5 parts of α-Al2O3 micro powder, calculated on the basis of 40-120 parts of magnesia. As an embodiment, the α-Al2O3 micro powder can be 2 parts, 3 parts or 4 parts in mass fraction. In the present application, the α-Al2O3 micro powder can promote sintering, thereby improving the strength and kiln skin hanging performance of the refractory material.

[0036] In the present application, the particle size of the α-Al2O3 micro powder is preferably 400-600 mesh. As an embodiment, the particle size of the α-Al2O3 micro powder can be 500 mesh.

[0037] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the present application comprises 0.1-2 parts of manganese dioxide powder, calculated on the basis of 40-120 parts of magnesia. As an embodiment, the manganese dioxide powder can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts or 1.9 parts in mass fraction. In the present application, the manganese ions in the manganese dioxide powder form a stable structure during sintering, thereby providing the strength and kiln skin hanging performance of the refractory material.

[0038] In the present application, the particle size of the manganese dioxide powder is preferably 300-500 mesh. As an embodiment, the particle size of the manganese dioxide powder can be 400 mesh.

[0039] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the present application comprises 0.1-2 parts of manganese powder, calculated on the basis of 40-120 parts of magnesia. As an embodiment, the manganese powder can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts or 1.9 parts in mass fraction. In the present application, the manganese powder forms a stable structure during sintering, thereby providing the strength and kiln skin hanging performance of the refractory material.

[0040] In the present application, the particle size of the manganese powder is preferably 300-500 mesh. As an embodiment, the particle size of the manganese powder can be 400 mesh.

[0041] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the application comprises 1-5 parts of a binder, based on 40-120 parts of magnesia. As an embodiment, the mass fraction of the binder can be 2 parts, 3 parts or 4 parts. In the application, the binder can be directly volatilized during sintering, and can ensure the initial strength after forming.

[0042] In the application, the binder preferably comprises at least one of a dextrin solution, a calcium lignosulfonate solution, a methyl cellulose solution and a sulfite pulp waste liquor. The application does not have special limitations on the concentration of the dextrin solution, the calcium lignosulfonate solution, the methyl cellulose solution and the sulfite pulp waste liquor, and a concentration known to those skilled in the art can be used.

[0043] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the application comprises 0.1-1 parts of an additive, based on 40-120 parts of magnesia. As an embodiment, the mass fraction of the additive can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts or 0.9 parts. In the application, the additive can accelerate the diffusion of the grain boundary, and can seal the pores inside the crystal grains, thereby reducing the thermal conductivity.

[0044] In the application, the additive is nano-zirconium oxide and nano-titanium oxide; and the mass ratio of the nano-zirconium oxide to the nano-titanium oxide is preferably 1: (1-5). As an embodiment, the mass ratio of the nano-zirconium oxide to the nano-titanium oxide can be 1:2, 1:3 or 1:4. The application can further reduce the thermal conductivity of the refractory material by controlling the mass ratio of the nano-zirconium oxide to the nano-titanium oxide.

[0045] In the application, the D50 of the additive is preferably 50-100 nm. 50 The particle size is preferably 50-100 nm.

[0046] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the application comprises 10-20 parts of calcium hexaluminate, based on 40-120 parts of magnesia. As an embodiment, the mass fraction of the calcium hexaluminate can be 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts or 19 parts. In the application, calcium hexaluminate has low thermal conductivity and excellent chemical corrosion resistance, and can effectively improve the corrosion resistance and reduce the thermal conductivity.

[0047] As an embodiment, the content of CaO in the calcium hexaluminate can be 8-10 wt%, and the sphericity can be 0.8-0.85.

[0048] In the application, the particle size of the calcium hexaluminate is preferably 0.1-0.3 mm.

[0049] The raw material for preparing the magnesium-manganese-aluminum composite spinel refractory material provided by the application, in the mass fraction of 40-120 parts of magnesia, comprises 5-15 parts of fiber. As an embodiment, the mass fraction of the fiber can be 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts. In the application, the fiber has a low thermal conductivity, can reduce the thermal conductivity, as a sintering aid, can promote the sintering of spinel, make the internal structure of the refractory material more compact, and significantly improve the strength.

[0050] In the application, the fiber is titanium dioxide-coated aluminum silicate fiber. In the application, the aluminum silicate fiber has excellent thermal stability and chemical stability, etc., and can improve the hanging kiln skin performance and corrosion resistance.

[0051] In the application, the mass ratio of the additive to calcium hexaluminate is preferably 1: (10-20). As an embodiment, the mass ratio of the additive to calcium hexaluminate can be 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18 or 1:19. The application can further reduce the thermal conductivity of the refractory material by controlling the mass ratio of the additive to calcium hexaluminate within the above range.

[0052] The additive and calcium hexaluminate in the application can synergistically reduce the thermal conductivity; wherein the additive can accelerate the grain boundary diffusion, close the pores inside the crystal grains, thereby reducing the thermal conductivity, calcium hexaluminate has a low thermal conductivity and excellent chemical corrosion resistance, can effectively improve the corrosion resistance and reduce the thermal conductivity; the fiber has a low thermal conductivity, can reduce the thermal conductivity, as a sintering aid, can promote the sintering of spinel, make the internal structure of the refractory material more compact, and significantly improve the strength; in addition, the aluminum silicate fiber has excellent thermal stability and chemical stability, etc., and can improve the hanging kiln skin performance and corrosion resistance.

[0053] The application also provides a preparation method of the magnesium-manganese-aluminum composite spinel refractory material described in the above technical solution, comprising the following steps:

[0054] (1) mixing magnesia, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, a binder, an additive, calcium hexaluminate and fiber to obtain a mixture;

[0055] (2) forming the mixture obtained in the step (1) to obtain a blank;

[0056] (3) sintering the blank obtained in the step (2) to obtain a magnesium-manganese-aluminum composite spinel refractory material.

[0057] The magnesium sand, iron-aluminum spinel, alpha-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additive, calcium hexaluminate and fiber are mixed to obtain a mixed material.

[0058] The mixing of the magnesium sand, iron-aluminum spinel, alpha-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additive, calcium hexaluminate and fiber is not particularly limited, and the technical solution for preparing the mixed material known to those skilled in the art can be used.

[0059] After obtaining the mixed material, the mixed material is formed to obtain a blank.

[0060] In the present application, the forming pressure is preferably 10-15 kN / cm 2 . As an embodiment, the forming pressure can be 11 kN / cm 2 , 12 kN / cm 2 , 13 kN / cm 2 or 14 kN / cm 2 .

[0061] The forming time is not particularly limited in the present application, as long as it can be formed.

[0062] After forming, the product obtained by forming is preferably dried to obtain a blank.

[0063] In the present application, the drying temperature is preferably 120-250°C, more preferably 150-200°C; and the drying time is preferably 48-72h, more preferably 55-60h.

[0064] After obtaining the blank, the blank is sintered to obtain a magnesium-manganese-aluminum composite spinel refractory material.

[0065] In the present application, the sintering temperature is preferably 1000-1300°C; and the sintering time is preferably 5-12h. As an embodiment, the sintering temperature can be 1050°C, 1100°C, 1150°C, 1200°C or 1250°C; and the sintering time can be 6h, 7h, 8h, 9h, 10h or 11h. The present application can form a stable organizational structure and mineral phase by sintering.

[0066] The preparation method provided by the present application has simple process.

[0067] The technical solutions in the present application will be clearly and completely described below with reference to the embodiments in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0068] Embodiment 1

[0069] A magnesium-manganese-aluminum composite spinel refractory is prepared from raw materials in the following mass fractions:

[0070] 40 parts of magnesite, 20 parts of hercynite, 1 part of α-Al2O3 micro powder, 2 parts of manganese dioxide powder, 0.1 part of manganese powder, 5 parts of a binder, 1 part of an additive, 20 parts of calcium hexaluminate and 5 parts of fiber;

[0071] The magnesite is magnesite particles and magnesite fine powder; the particle size of the magnesite particles is 3-5 mm; the particle size of the magnesite fine powder is 0.063 mm or less; and the mass ratio of the magnesite particles to the magnesite fine powder is 1:1;

[0072] The magnesite is fused magnesite; and the mass percentage content of MgO in the magnesite is 96%;

[0073] The particle size of the hercynite is 1-3 mm;

[0074] The chemical components of the hercynite are, in mass percentage, Fe2O340.22%, SiO21.32%, Al2O355.81% and CaO 2.65%;

[0075] The particle size of the α-Al2O3 micro powder is 500 mesh;

[0076] The particle size of the manganese dioxide powder is 400 mesh;

[0077] The particle size of the manganese powder is 300 mesh;

[0078] The binder is a calcium lignosulfonate solution, and the concentration of the calcium lignosulfonate solution is 1.23 g / mL;

[0079] The additive is nano-zirconium oxide and nano-titanium oxide; and the mass ratio of the nano-zirconium oxide to the nano-titanium oxide is 1:2;

[0080] The D50 of the additive is 50 nm; 50 The particle size is 50 nm;

[0081] The content of CaO in the calcium hexaluminate is 8 wt%, and the sphericity is 0.8;

[0082] The particle size of the calcium hexaluminate is 0.1 mm;

[0083] The fiber is titanium dioxide-coated aluminum silicate fiber, and the preparation method is as follows: 0.05 L of tetrabutyl titanate is uniformly dispersed in 30 L of anhydrous ethanol, then 1 kg of aluminum silicate fiber is uniformly mixed, and then the solvent is evaporated to obtain the fiber; wherein the Al2O3 content in the aluminum carbonate fiber is 65.07 wt%, the SiO2 content is 34.13 wt%, the diameter is 3 μm, and the length is 3 mm;

[0084] The mass ratio of the additive to calcium hexaluminate is 1:20;

[0085] The preparation method of the magnesium-manganese-aluminum composite spinel refractory material is as follows:

[0086] (1) magnesium sand, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additive, calcium hexaluminate, and fiber are mixed to obtain a mixture;

[0087] (2) the mixture obtained in step (1) is formed under a pressure of 10 kN / cm 2 , and then dried at 150°C for 50 h to obtain a blank;

[0088] (3) the blank obtained in step (2) is sintered at 1200°C for 10 h to obtain a magnesium-manganese-aluminum composite spinel refractory material.

[0089] Comparative Example 1

[0090] On the basis of Example 1, the additive is omitted, the mass of calcium hexaluminate is set to 21 parts, and other conditions remain unchanged.

[0091] Comparative Example 2

[0092] On the basis of Example 1, calcium hexaluminate is omitted, and the mass of the additive is set to 21 parts, and other conditions remain unchanged.

[0093] Comparative Example 3

[0094] Conventional ordinary cement kiln brick

[0095] The magnesium-manganese-aluminum composite spinel refractory materials prepared in Example 1 and Comparative Examples 1-3 are subjected to performance testing, and the results are shown in Table 1.

[0096] Table 1 Performance data of the magnesium-manganese-aluminum composite spinel refractory materials prepared in Example 1 and Comparative Examples 1-3

[0097]

[0098] The greater the volume density, the lower the apparent porosity, the greater the cold compressive strength in table 1 proves that sintering is dense, the lower the thermal conductivity, the smaller the kiln heat loss, the lower the corrosion resistance value, the smaller the amount of corrosion loss, the better the corrosion resistance, and the greater the adhesion strength value of the kiln skin proves that the kiln skin performance is better.

[0099] As can be seen from table 1, the additive and calcium hexaluminate in the application can synergistically reduce the thermal conductivity, and omitting the additive or calcium hexaluminate will reduce the thermal conductivity.

[0100] Example 2

[0101] On the basis of example 1, the mass ratio of nano zirconium oxide and nano titanium oxide is set to 1:1, and other conditions remain unchanged.

[0102] Example 3

[0103] On the basis of example 1, the mass ratio of nano zirconium oxide and nano titanium oxide is set to 1:3, and other conditions remain unchanged.

[0104] Example 4

[0105] On the basis of example 1, the mass ratio of nano zirconium oxide and nano titanium oxide is set to 1:4, and other conditions remain unchanged.

[0106] Example 5

[0107] On the basis of example 1, the mass ratio of nano zirconium oxide and nano titanium oxide is set to 1:5, and other conditions remain unchanged.

[0108] The magnesium-manganese-aluminum composite spinel refractory materials prepared in examples 1-5 are tested for performance, and the results are shown in table 2, and the test standards are the same as those in table 1.

[0109] Table 2 Performance data of magnesium-manganese-aluminum composite spinel refractory materials prepared in examples 1-5

[0110]

[0111] Example 6

[0112] On the basis of example 1, the mass fraction of calcium hexaluminate is set to 10 parts, that is, the mass ratio of additive and calcium hexaluminate is 1:10, and other conditions remain unchanged.

[0113] Example 7

[0114] On the basis of example 1, the mass fraction of calcium hexaluminate is set to 15 parts, that is, the mass ratio of additive and calcium hexaluminate is 1:15, and other conditions remain unchanged.

[0115] Example 8

[0116] The mass fraction of calcium hexaluminate is set to 16 parts based on example 1, that is, the mass ratio of the additive and calcium hexaluminate is 1:16, and other conditions remain unchanged.

[0117] The magnesium-manganese-aluminum composite spinel refractory prepared in example 1 and examples 6-8 is subjected to performance testing, and the results are shown in table 3. The testing standards are the same as those in table 1.

[0118] Table 3 Performance data of the magnesium-manganese-aluminum composite spinel refractory prepared in example 1 and examples 6-8

[0119]

[0120] Example 9

[0121] A magnesium-manganese-aluminum composite spinel refractory is prepared from the following raw materials in mass fraction:

[0122] Magnesite 120 parts, hercynite 1 part, α-Al2O3 micro powder 5 parts, manganese dioxide powder 0.1 part, manganese powder 2 parts, binder 1 part, additive 0.5 part, calcium hexaluminate 10 parts, and fiber 15 parts;

[0123] The magnesite is magnesite particles and magnesite fine powder; the particle size of the magnesite particles is 3-5 mm; the particle size of the magnesite fine powder is 0.063 mm or less; and the mass ratio of the magnesite particles and the magnesite fine powder is 5:1;

[0124] The magnesite is fused magnesite; and the mass percentage content of MgO in the magnesite is 96%;

[0125] The particle size of the hercynite is 1-3 mm;

[0126] The chemical composition of the hercynite is Fe2O340.22%, SiO21.32%, Al2O355.81%, and CaO 2.65% in mass percentage;

[0127] The particle size of the α-Al2O3 micro powder is 500 mesh;

[0128] The particle size of the manganese dioxide powder is 400 mesh;

[0129] The particle size of the manganese powder is 300 mesh;

[0130] The binder is a calcium lignosulfonate solution, and the concentration of the calcium lignosulfonate solution is 1.23 g / mL;

[0131] The additive is nano-zirconium oxide and nano-titanium oxide; and the mass ratio of the nano-zirconium oxide and the nano-titanium oxide is 1:3;

[0132] The D50 of the additive is 50 nm.50 The particle size of the calcium aluminate is 50 nm;

[0133] The content of CaO in the calcium aluminate is 8 wt%, and the sphericity is 0.8;

[0134] The particle size of the calcium aluminate is 0.1 mm;

[0135] The fiber is titanium dioxide coated aluminum silicate fiber, and the preparation method is as follows: 0.05 L of tetrabutyl titanate is uniformly dispersed in 30 L of anhydrous ethanol, then 1 kg of aluminum silicate fiber is uniformly mixed, and then the solvent is evaporated to obtain the fiber; wherein the content of Al2O3 in the aluminum silicate fiber is 65.07 wt%, the content of SiO2 is 34.13 wt%, the diameter is 3 μm, and the length is 3 mm;

[0136] The mass ratio of the additive to the calcium aluminate is 1:20;

[0137] The preparation method of the magnesium-manganese-aluminum composite spinel refractory material comprises the following steps:

[0138] (1) magnesium sand, iron-aluminum spinel, α-Al2O3 powder, manganese dioxide powder, manganese powder, binder, additive, calcium aluminate, and fiber are mixed to obtain a mixture;

[0139] (2) the mixture obtained in step (1) is formed under a pressure of 12 kN / cm 2 , and then dried at 150 ℃ for 50 h to obtain a blank;

[0140] (3) the blank obtained in step (2) is sintered at 1300 ℃ for 8 h to obtain a magnesium-manganese-aluminum composite spinel refractory material.

[0141] Example 10

[0142] A magnesium-manganese-aluminum composite spinel refractory material is prepared from the following raw materials in mass parts:

[0143] 80 parts of magnesium sand, 10 parts of iron-aluminum spinel, 3 parts of α-Al2O3 powder, 1 part of manganese dioxide powder, 1 part of manganese powder, 2 parts of binder, 0.5 parts of additive, 10 parts of calcium aluminate, and 8 parts of fiber;

[0144] The magnesium sand is magnesium sand particles and magnesium sand fine powder; the particle size of the magnesium sand particles is 3-5 mm; the particle size of the magnesium sand fine powder is less than 0.063 mm; and the mass ratio of the magnesium sand particles to the magnesium sand fine powder is 3:1;

[0145] The magnesium sand is electrically fused magnesium sand; and the mass percentage content of MgO in the magnesium sand is 96%;

[0146] The particle size of the iron-aluminum spinel is 1-3 mm;

[0147] The chemical composition of the iron-aluminum spinel is Fe2O340.22%, SiO21.32%, Al2O355.81%, and CaO 2.65% in mass percentage;

[0148] The particle size of the α-Al2O3 micro powder is 500 mesh;

[0149] The particle size of the manganese dioxide powder is 400 mesh;

[0150] The particle size of the manganese powder is 300 mesh;

[0151] The binder is a calcium lignosulfonate solution, and the concentration of the calcium lignosulfonate solution is 1.23 g / mL;

[0152] The additive is nano-zirconium oxide and nano-titanium oxide, and the mass ratio of the nano-zirconium oxide to the nano-titanium oxide is 1:4;

[0153] The D50 of the additive is 50 nm; 50 The particle size is 50 nm;

[0154] The content of CaO in the calcium hexaluminate is 8 wt%, and the sphericity is 0.8;

[0155] The particle size of the calcium hexaluminate is 0.1 mm;

[0156] The fiber is a titanium dioxide-coated aluminum silicate fiber, and the preparation method is as follows: 0.05 L of tetrabutyl titanate is added into 30 L of anhydrous ethanol to disperse uniformly, then 1 kg of aluminum silicate fiber is added to mix uniformly, and then the solvent is evaporated to obtain the fiber; wherein, the Al2O3 content in the aluminum silicate fiber is 65.07 wt%, the SiO2 content is 34.13 wt%, the diameter is 3 μm, and the length is 3 mm;

[0157] The mass ratio of the additive to the calcium hexaluminate is 1:20;

[0158] The preparation method of the magnesium-manganese-aluminum composite spinel refractory material is as follows:

[0159] (1) magnesium sand, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additive, calcium hexaluminate, and fiber are mixed to obtain a mixture;

[0160] (2) the mixture obtained in step (1) is formed under a pressure of 15 kN / cm2, and then dried at 150°C for 50 h to obtain a blank; 2

[0161] (3) the blank obtained in step (2) is sintered at 1100°C for 12 h to obtain a magnesium-manganese-aluminum composite spinel refractory material. ​

[0162] The magnesium-manganese-aluminum composite spinel refractory prepared in Example 1 and Examples 9-10 was tested for performance, and the results are shown in Table 4, with the same testing standards as in Table 1.

[0163] Table 4 Performance data of the magnesium-manganese-aluminum composite spinel refractory prepared in Example 1 and Examples 9-10

[0164]

[0165] As can be seen from the above examples and comparative examples, the magnesium-manganese-aluminum composite spinel refractory provided by the present application has excellent strength, hanging kiln skin performance, corrosion resistance and low thermal conductivity.

[0166] The above description is merely preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of protection of the present application.

Claims

1. A magnesium-manganese-aluminum composite spinel refractory material, characterized in that, It is prepared from raw materials comprising the following parts by mass: Magnesia 40-120 parts, iron-aluminum spinel 1-20 parts, α-Al2O3 micro powder 1-5 parts, manganese dioxide powder 0.1-2 parts, manganese powder 0.1-2 parts, binder 1-5 parts, additives 0.1-1 parts, calcium hexaaluminate 10-20 parts, and fiber 5-15 parts; The fiber is titanium dioxide coated aluminum silicate fiber; The additives are nano-zirconia and nano-titanium oxide; The mass ratio of nano-zirconia to nano-titanium oxide is 1:(1~5). The mass ratio of the additive to calcium hexaaluminate is 1:(10~20). The preparation method of the magnesium-manganese-aluminum composite spinel refractory material includes the following steps: (1) Mix magnesia, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additives, calcium hexaaluminate and fiber to obtain a mixture; (2) The mixture obtained in step (1) is shaped to obtain a blank; (3) The billet obtained in step (2) is sintered to obtain magnesium manganese aluminum composite spinel refractory material; The forming pressure in step (2) is 10~15kN / cm. 2 ; The sintering temperature in step (3) is 1000~1300℃, and the sintering time is 5~12h; The magnesia includes magnesia particles and magnesia powder; the particle size of the magnesia particles is 3~5mm; the particle size of the magnesia powder is less than 0.063mm; the mass ratio of the magnesia particles to the magnesia powder is (1~5):1; The magnesia includes fused magnesia and / or sintered magnesia; the magnesia contains ≥96% MgO by mass. The binder includes at least one of dextrin solution, calcium lignosulfonate solution, methylcellulose solution, and sulfite pulp waste liquor; The method for preparing titanium dioxide-coated aluminum silicate fiber is as follows: 0.05L of tetrabutyl titanate is added to 30L of anhydrous ethanol and dispersed evenly, then 1kg of aluminum silicate fiber is added and mixed evenly, and then the solvent is evaporated to obtain titanium dioxide-coated aluminum silicate fiber.

2. The magnesium-manganese-aluminum composite spinel refractory material according to claim 1, characterized in that, It is prepared from raw materials comprising the following mass percentages: The ingredients are: 50-100 parts magnesia, 5-15 parts iron-aluminum spinel, 2-4 parts α-Al2O3 micro powder, 0.5-1.5 parts manganese dioxide powder, 0.5-1.5 parts manganese powder, 2-4 parts binder, 0.2-0.9 parts additives, 12-18 parts calcium hexaaluminate, and 8-12 parts fiber.

3. The magnesium-manganese-aluminum composite spinel refractory material according to claim 1 or 2, characterized in that, The particle size of the α-Al2O3 micro powder is 400~600 mesh.

4. The magnesium-manganese-aluminum composite spinel refractory material according to claim 1 or 2, characterized in that, The particle size of the manganese dioxide powder is 300-500 mesh.

5. The magnesium-manganese-aluminum composite spinel refractory material according to claim 1, characterized in that, The mass ratio of the additive to calcium hexaaluminate is 1:(14~16).

6. A method for preparing the magnesium-manganese-aluminum composite spinel refractory material according to any one of claims 1 to 5, comprising the following steps: (1) Mix magnesia, iron-aluminum spinel, α-Al2O3 micro powder, manganese dioxide powder, manganese powder, binder, additives, calcium hexaaluminate and fiber to obtain a mixture; (2) The mixture obtained in step (1) is shaped to obtain a blank; (3) The billet obtained in step (2) is sintered to obtain magnesium manganese aluminum composite spinel refractory material.

7. The preparation method according to claim 6, characterized in that, The forming pressure in step (2) is 10~15kN / cm. 2 .

8. The preparation method according to claim 6, characterized in that, The sintering temperature in step (3) is 1000~1300℃, and the sintering time is 5~12h.

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