A kind of anti-deformation multilayer heat insulation composite brick for rotary kiln and preparation method thereof

Abstract

The application discloses a kind of anti-deformation rotary kiln multilayer heat insulation composite brick, by coarse aggregate, fine aggregate, auxiliary material, modified rheological agent composition, wherein, the coarse aggregate is by electric smelting magnesia-alumina spinel, electric smelting magnesite, sintered magnesite composition;The fine aggregate is by active magnesia-alumina spinel micro powder and lanthanum oxide micro powder composition;The auxiliary material is by chlorinated paraffin, foamed microbead, binder composition;The modified rheological agent is by modified monomer and ammonium persulfate, methacrylic acid, methoxy polyethylene glycol, glycerol monostearate synthesis obtains;The preparation method of above-mentioned composite brick includes the following steps: S1, work raw material preparation;S2, heat insulation raw material preparation;S3, press into billet;S4, firing molding;The composite brick of the application is heat-insulated by magnesia-alumina spinel etc., and the rheological property of the composite brick is improved by adding modified rheological agent, so as to improve the degree of anti-deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refractory materials, in particular to a multi-layer heat insulation composite brick for a rotary kiln and a preparation method thereof. BACKGROUND

[0002] The temperature in the rotary kiln is usually above 1400 degrees Celsius, which can fully calcine the raw materials to form clinker. Through rotary motion, the raw materials are uniformly heated in the kiln, which is conducive to the calcination reaction.

[0003] Common heat insulation materials for rotary kilns include ① refractory bricks: a kind of high-temperature resistant material made by high-temperature firing, which has good fire resistance and heat insulation performance, commonly used for internal lining and external heat insulation of rotary kiln. ②Refractory castable: a kind of refractory material made by mixing specific proportion of refractory particles, binder and additives according to certain process method, suitable for overall casting of rotary kiln shell. ③Heat insulation brick: a kind of light and porous heat insulation material, commonly used for external heat insulation layer of rotary kiln, which can effectively reduce heat conduction. ④Ceramic particle insulation board: composed of ceramic particles, binder, etc., light in texture, good in heat preservation effect, suitable for external heat insulation of rotary kiln.

[0004] When heated, the refractory brick will expand and change due to thermal stress, which will cause deformation. Therefore, the present application designs a multi-layer heat insulation composite brick for rotary kiln to solve the above problems. SUMMARY

[0005] To solve the above technical problems, the present application provides a multi-layer heat insulation composite brick for rotary kiln and a preparation method thereof.

[0006] The technical scheme of the present application is: a multi-layer heat insulation composite brick for rotary kiln, which is composed of coarse aggregate, fine aggregate, auxiliary material and modified rheological agent, and the mass percentage of each component is:

[0007] Fine aggregate: 11-15%,

[0008] Auxiliary material: 3.8-6.7%,

[0009] Modified rheological agent: 0.7-1%,

[0010] Coarse aggregate: the rest;

[0011] The coarse aggregate is composed of fused magnesia-alumina spinel, fused magnesia and sintered magnesia in a mass ratio of 8-10:25-30:37.3-51.5.

[0012] The fine aggregate is composed of active magnesium-aluminum spinel micro powder and lanthanum oxide micro powder in a mass ratio of 8-10:3-5.

[0013] The auxiliary material is composed of chlorinated paraffin, foaming microbeads and a binding agent in a mass ratio of 2-4:1-1.5:0.8-1.2.

[0014] The modified rheological agent is synthesized from a modified monomer, ammonium persulfate, methacrylic acid, methoxy polyethylene glycol and glycerol monostearate in a weight ratio of 1-1.5:0.05:0.06:0.005-0.009:0.001-0.002.

[0015] Further, the foaming microbeads have a particle size of 15-20 mu m and include, by weight fraction, 15-20 parts of hydrogenated polyether, 12-15 parts of azobisformamide and 1-2 parts of trimethylhexamethylene diamine.

[0016] Description: The above raw materials are used as foaming microbeads, which have the advantages of non-flammability, large foaming amount and low cost.

[0017] Further, the binding agent is calcium aluminate cement with a water content of 2.5-3.5wt%, which includes, by mass percentage, 70-72% of aluminum oxide, 15-17% of calcium oxide, 10-13% of magnesium oxide, and the balance of silicon dioxide and iron oxide, wherein the mass ratio of silicon dioxide to iron oxide is 1:0.8.

[0018] Description: The calcium aluminate cement has high early strength, can obtain high strength in a short time, and has controllable construction performance and stable and uniform performance.

[0019] Further, the preparation method of the modified monomer includes the following steps:

[0020] The modified monomer is obtained by mixing diethylene glycol dibenzoate with propionamide and dipelargonate in a mass ratio of 1-2:0.06:0.02 for 1-1.5h, then adding sodium hypophosphite under argon atmosphere, and then performing hydrothermal reaction at 165-175℃ for 21-22h, and then dehydrating at 85-95℃ for 40-50min; wherein the mass ratio of diethylene glycol dibenzoate:propionamide:dipelargonate:sodium hypophosphite is 1-2:0.06:0.02:0.03.

[0021] Description: The diethylene glycol dibenzoate is modified under hydrothermal reaction to obtain the modified monomer, which is easy to be modified subsequently.

[0022] Further, the preparation method of the modified rheological agent includes the following steps:

[0023] 1) mix the modified monomer, ammonium persulfate, methacrylic acid and water for 2-3 hours to obtain a mixed solution A;

[0024] 2) mix the methoxy polyethylene glycol, glycerol monostearate and water to obtain a mixed solution B, then add the mixed solution A dropwise into the mixed solution B and react for 1-3 hours, and then adjust the pH to 6-7 to obtain the modified rheological agent;

[0025] In the mixed solution A, the mass percentage of water is 35-37%; in the mixed solution B, the mass percentage of water is 94-96%.

[0026] Description: The modified monomer is used to synthesize the rheological agent with amide compounds, acrylic acid and polyester monomers, so as to improve the cohesion of the rheological agent to the composite brick raw materials, improve the flow absorption capacity of the composite brick raw materials to thermal expansion and thermal stress, and further improve the deformation resistance of the composite brick.

[0027] The preparation method of the above-mentioned anti-deformation multi-layer heat insulation composite brick for rotary kiln comprises the following steps:

[0028] S1, work material preparation:

[0029] Take 1 / 2-2 / 3 of sintered magnesia, 1 / 2-2 / 3 of fused magnesia-alumina spinel, 1 / 2-2 / 3 of high-purity fused magnesia, 1 / 2-2 / 3 of active magnesia-alumina spinel micro powder, lanthanum oxide micro powder, chlorinated paraffin and 1 / 2-2 / 3 of binder and mix them uniformly to obtain the work material;

[0030] S2, heat insulation material preparation:

[0031] Mix the remaining 1 / 3-1 / 2 of sintered magnesia, the remaining 1 / 3-1 / 2 of fused magnesia-alumina spinel, the remaining 1 / 3-1 / 2 of high-purity fused magnesia, the remaining 1 / 3-1 / 2 of active magnesia-alumina spinel micro powder and the remaining 1 / 3-1 / 2 of binder uniformly to obtain mixed material A; then mix the foamed microbeads and the modified rheological agent uniformly to obtain mixed material B; the mixing speed is 550-650 r / min;

[0032] Spray mixed material B into mixed material A at a spraying rate of 350-450 m / s, and obtain the heat insulation material after spraying is completed;

[0033] In step S1, the mass ratio of sintered magnesia, fused magnesia-alumina spinel, high-purity fused magnesia, active magnesia-alumina spinel micro powder and binder to the same raw materials in step S2 is 1-2:1;

[0034] S3, pressing into a blank:

[0035] Divide the working raw materials into three parts, divide the heat insulation raw materials into two parts, and press the three working raw materials into working powder blocks (1) and the two heat insulation raw materials into heat insulation powder blocks (2), then perform four times of stacking and pressing according to the stacking order of the working powder blocks (1)-heat insulation powder blocks (2) to obtain composite brick blanks;

[0036] The pressing pressure of the working powder blocks (1) is 45-50 MPa, and the pressing pressure of the heat insulation powder blocks (2) is 30-40 MPa.

[0037] The method of the four times of stacking and pressing is as follows: the first time, the pressure is 55-60 MPa, and the heating temperature is 185-195℃; the second time, the pressure is 110-115% of the first time, and the heating temperature is 200-205℃; the third time, the pressure is 120-125% of the second time, and the heating temperature is 210-220℃; the fourth time, the pressure is 70-75% of the third time, and the heating temperature is 195-200℃.

[0038] S4, firing the mold:

[0039] Dry the composite brick blanks obtained in step S3 to a water content of <0.4%, then fire the dried composite brick blanks at 1300-1400℃ for 12-14h, and cool to room temperature to obtain heat insulation composite bricks.

[0040] Further, in step S1, the sintered magnesia, the fused magnesia-alumina spinel, the high-purity fused magnesia, the active magnesia-alumina spinel micropowder, the lanthanum oxide micropowder, and the binder are mixed at a rotation speed of 450-500r / min, and every 3-5min during the mixing process, 1 / 5-2 / 5 of the chlorinated paraffin is sprayed until the spraying of the chlorinated paraffin is completed.

[0041] Description: Spraying the chlorinated paraffin in batches can make the chlorinated paraffin more evenly wrapped on the surface of other materials, thereby improving the toughness of the materials and the overall toughness and deformation resistance of the composite bricks.

[0042] Further, in step S3, before each pressing of the four times of stacking and pressing, the bonding surface of the working powder blocks (1) and the heat insulation powder blocks (2) is subjected to corona treatment for 15-20s, and the power of the corona is 4-6kW.

[0043] Description: Corona treatment of the bonding surface of the two can improve the adhesion of the bonding surface, thereby improving the bonding force of the two during pressing and the overall stability of the composite bricks.

[0044] Further, in step S4, the drying method is as follows: first, dry at a vacuum degree of 75-80Pa and a temperature of 60-80℃ for 3-4h, and then air-cool dry at 20-30℃ for 2-2.5h.

[0045] The vacuum drying and air cooling drying can make the water in the composite brick body evaporate rapidly, so that the excessive water in the composite brick body is prevented, and the problems such as cracking and deformation of the prepared composite brick are avoided.

[0046] The present application has the following advantages:

[0047] (1) The heat-insulating composite brick of the present application uses magnesium-aluminum spinel and magnesia as main raw materials, and has high strength, corrosion resistance, low linear expansion coefficient and good thermal shock resistance. The addition of lanthanum oxide can improve the thermal stability and shock resistance of the heat-insulating composite brick, so that the heat-insulating composite brick has better high-temperature resistance and longer service life. The addition of chlorinated paraffin can enhance the toughness of the heat-insulating composite brick, and the addition of foamed microbeads and modified rheological agent can make the raw materials more densely combined together, improve the stability of the heat-insulating composite brick, and make the thermal stress more evenly flow and disperse in the heat-insulating composite brick when the heat-insulating composite brick is heated, so that the heat-insulating composite brick will not crack.

[0048] (2) The heat-insulating composite brick of the present application is prepared by separating the working raw materials and the heat-insulating raw materials. The original high-performance material is retained in the working layer of the firebrick, and low-thermal-conductivity material is used in the non-working layer, so as to enhance the performance of each raw material block and improve the heat-insulating property and toughness of the working raw materials and the rheological property of the heat-insulating raw materials, thereby enhancing the heat-insulating and anti-deformation performance of the whole heat-insulating composite brick.

[0049] (3) The heat-insulating composite brick of the present application is prepared by stacking and compounding the working blocks and the heat-insulating blocks, so that the working blocks are first heat-insulated to reduce heat conduction, and then the heat-insulating blocks are used to reduce the thermal conductivity, further inhibit the heat transfer in the heat-insulating composite brick, and the structure of the brick body is more stable by stacking and pressing different levels of materials. The bonding force of the two is enhanced by adjusting the pressing pressure and pressing temperature during compounding. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a structural diagram of the heat-insulating composite brick of the present application.

[0051] Among them, 1 is a working block, and 2 is a heat-insulating block. DETAILED DESCRIPTION

[0052] The present application will be further described in detail in combination with specific embodiments to better reflect the advantages of the present application.

[0053] Example 1

[0054] A multilayer heat-insulating composite brick for a rotary kiln with anti-deformation is composed of coarse aggregate, fine aggregate, auxiliary material and modified rheological agent, and the mass percentage of each component is:

[0055] Fine aggregate: 13%,

[0056] Auxiliary material: 5.3%,

[0057] Modified rheological agent: 0.85%,

[0058] Coarse aggregate: the balance;

[0059] The coarse aggregate is composed of fused magnesium-aluminum spinel, fused magnesia, and sintered magnesia in a mass ratio of 9:28:7.1;

[0060] The fine aggregate is composed of active magnesium-aluminum spinel micro powder and lanthanum oxide micro powder in a mass ratio of 9:4;

[0061] The auxiliary material is composed of chlorinated paraffin, foaming microbeads, and binding agent in a mass ratio of 3:1.3:1.0;

[0062] The modified rheological agent is synthesized from a modified monomer, ammonium persulfate, methacrylic acid, methoxy polyethylene glycol, and glycerol monostearate in a weight ratio of 1.3:0.05:0.06:0.007:0.0015;

[0063] The foaming microbeads have a particle size of 16-18 μm and include, by weight fraction: 18 parts of hydrogenated polyether, 13 parts of azobisformamide, and 1.5 parts of trimethylhexamethylene diamine;

[0064] The binding agent is calcium alumino-magnesia cement with a water content of 3.0%, which includes, by mass percentage: 71% of aluminum oxide, 16% of calcium oxide, 12% of magnesium oxide, and the balance of silicon dioxide and iron oxide, wherein the mass ratio of silicon dioxide to iron oxide is 1:0.8;

[0065] The preparation method of the modified monomer includes the following steps:

[0066] After mixing diethylene glycol dibenzoate, propionamide, and bis-decanoate in a mass ratio of 1.5:0.06:0.02 for 1.3 h, sodium hypophosphite is added under an argon environment, and then hydrothermal reaction is performed at 170°C for 21.5 h, followed by dehydration at 90°C for 45 min to obtain the modified monomer; wherein the mass ratio of diethylene glycol dibenzoate: propionamide: bis-decanoate: sodium hypophosphite is 1.5:0.06:0.02:0.03;

[0067] The preparation method of the modified rheological agent includes the following steps:

[0068] 1) The modified monomer, ammonium persulfate, methacrylic acid, and water are mixed for 2.5 h to obtain a mixed solution A;

[0069] 2) mixing methoxypolyethylene glycol, glycerol monostearate and water to obtain a mixed solution B, and then adding the mixed solution A dropwise into the mixed solution B to react for 2 hours, and adjusting the pH to 6.5 by using a 30% sodium hydroxide solution to obtain the modified rheological agent;

[0070] In the mixed solution A, the mass percentage of water is 36%; in the mixed solution B, the mass percentage of water is 95%.

[0071] Example 2

[0072] The preparation method of the anti-deformation multi-layer heat insulation composite brick for a rotary kiln in Example 1 comprises the following steps:

[0073] S1, preparation of working raw materials:

[0074] 5 / 6 of sintered magnesia, 5 / 6 of fused magnesia-alumina spinel, 5 / 6 of high-purity fused magnesia, 5 / 6 of active magnesia-alumina spinel micro powder, lanthanum oxide micro powder and 5 / 6 of a binder are mixed at a rotation speed of 475 r / min, and 3 / 10 of chlorinated paraffin is sprayed every 4 minutes during the mixing process until the spraying of chlorinated paraffin is completed;

[0075] S2, preparation of heat insulation raw materials:

[0076] The remaining 1 / 6 of sintered magnesia, the remaining 1 / 6 of fused magnesia-alumina spinel, the remaining 1 / 6 of high-purity fused magnesia, the remaining 1 / 6 of active magnesia-alumina spinel micro powder and the remaining 1 / 6 of the binder are uniformly mixed to obtain mixed material A; and the foamed microbeads and the modified rheological agent are uniformly mixed to obtain mixed material B; the mixing rotation speed is 600 r / min;

[0077] The mixed material B is sprayed into the mixed material A at a spraying rate of 400 m / s, and the heat insulation raw materials are obtained after the spraying is completed;

[0078] In step S1, the mass ratio of sintered magnesia, fused magnesia-alumina spinel, high-purity fused magnesia, active magnesia-alumina spinel micro powder and binder to the same raw materials in step S2 is 1.5:1;

[0079] S3, pressing into a blank:

[0080] The working raw materials are divided into three equal parts, and the heat insulation raw materials are divided into two equal parts, and the three working raw materials are pressed into working powder blocks 1, and the two heat insulation raw materials are pressed into heat insulation powder blocks 2; in step S3, the pressing pressure of the working powder block 1 is 48 MPa; and the pressing pressure of the heat insulation powder block 2 is 35 MPa;

[0081] Then, the working powder block 1 and the heat insulation powder block 2 are stacked and pressed four times according to the stacking order to obtain a composite brick blank;

[0082] The four times superimposed pressing method is: the first time pressure is 58 MPa, heating temperature is 190℃; the second time pressure is 112% of the first time, i.e. 64.96 MPa, heating temperature is 203℃; the third time pressure is 122% of the second time, i.e. 79.25 MPa, heating temperature is 215℃; the fourth time pressure is 72% of the third time, i.e. 57.06 MPa, heating temperature is 198℃;

[0083] Before each time of the four times superimposed pressing, the combined surface of the working powder block 1 and the heat insulation powder block 2 is treated by corona for 18s, and the power of the corona is 5kW;

[0084] S4, firing forming:

[0085] The composite brick blank obtained in step S3 is dried at a vacuum degree of 78Pa and a temperature of 70℃ for 3.5h, and then air-cooled dried at 25℃ for 2.3h, and the water content is 0.32%, and then the dried composite brick blank is fired at 1350℃ for 13h, and the heat insulation composite brick is obtained after cooling to room temperature.

[0086] Example 3

[0087] The difference between this embodiment and example 1 is that the mass percentage of each component is:

[0088] Fine aggregate: 11%,

[0089] Auxiliary material: 3.8%,

[0090] Modified rheological agent: 0.7%,

[0091] Coarse aggregate: the rest;

[0092] The coarse aggregate is composed of fused magnesium-aluminum spinel, fused magnesia, and sintered magnesia in a mass ratio of 10:30:51.5;

[0093] The fine aggregate is composed of active magnesium-aluminum spinel micro powder and lanthanum oxide micro powder in a mass ratio of 8:3;

[0094] The auxiliary material is composed of chlorinated paraffin, foaming microbeads, and binding agent in a mass ratio of 2:1:0.8.

[0095] Example 4

[0096] The difference between this embodiment and example 1 is that the mass percentage of each component is:

[0097] Fine aggregate: 15%,

[0098] Auxiliary material: 6.7%,

[0099] Modified rheological agent: 1%,

[0100] Coarse aggregate: balance;

[0101] The coarse aggregate is composed of fused magnesia-alumina spinel, fused magnesia, and sintered magnesia in a mass ratio of 8:25:37.3.

[0102] The fine aggregate is composed of active magnesia-alumina spinel micro powder and lanthanum oxide micro powder in a mass ratio of 10:5.

[0103] The auxiliary material is composed of chlorinated paraffin, foamed microbeads, and a binding agent in a mass ratio of 4:1.5:1.2.

[0104] Example 5

[0105] The difference between this example and Example 1 is that the particle size of the foamed microbeads is 15-16 μm, and the foamed microbeads include, by weight fraction, 15 parts of hydrogenated polyether, 12 parts of azodicarbonamide, and 2 parts of trimethylhexamethylene diamine.

[0106] Example 6

[0107] The difference between this example and Example 1 is that the particle size of the foamed microbeads is 18-20 μm, and the foamed microbeads include, by weight fraction, 20 parts of hydrogenated polyether, 15 parts of azodicarbonamide, and 1 part of trimethylhexamethylene diamine.

[0108] Example 7

[0109] The difference between this example and Example 1 is that the binding agent is calcium aluminate cement with a water content of 2.5 wt%, and the calcium aluminate cement includes, by mass percentage, 72% of aluminum oxide, 15-20% of calcium oxide, 10% of magnesium oxide, and the balance of silicon dioxide and iron oxide, wherein the mass ratio of silicon dioxide to iron oxide is 1:0.8.

[0110] Example 8

[0111] The difference between this example and Example 1 is that the binding agent is calcium aluminate cement with a water content of 3.5 wt%, and the calcium aluminate cement includes, by mass percentage, 70% of aluminum oxide, 17% of calcium oxide, 13% of magnesium oxide, and the balance of silicon dioxide and iron oxide, wherein the mass ratio of silicon dioxide to iron oxide is 1:0.8.

[0112] Example 9

[0113] The difference between this example and Example 1 is that the modified rheological agent is synthesized from a modified monomer, ammonium persulfate, methacrylic acid, methoxy polyethylene glycol, and glycerol monostearate in a weight ratio of 1:0.05:0.06:0.009:0.002.

[0114] The preparation method of the modified monomer includes the following steps:

[0115] The modified monomer is obtained by mixing diethylene glycol dibenzoate, propionamide and bis-decanedioic acid in a mass ratio of 1:0.06:0.02 for 1.5 hours, then adding sodium hypophosphite under an argon atmosphere, and then performing hydrothermal reaction at 175 DEG C for 22 hours and dehydration at 95 DEG C for 50 minutes; wherein the mass ratio of diethylene glycol dibenzoate: propionamide: bis-decanedioic acid: sodium hypophosphite is 2:0.06:0.02:0.03.

[0116] The preparation method of the modified rheological agent comprises the following steps:

[0117] 1) mixing the modified monomer, ammonium persulfate and methacrylic acid with water for 2 hours to obtain a mixed solution A;

[0118] 2) mixing methoxypolyethylene glycol and glycerol monostearate with water to obtain a mixed solution B, then adding the mixed solution A dropwise into the mixed solution B and reacting for 1 hour, and then adjusting the pH to 6 to obtain the modified rheological agent;

[0119] In the mixed solution A, the mass percentage of water is 37%; in the mixed solution B, the mass percentage of water is 96%.

[0120] Example 10

[0121] The difference between the present example and Example 1 is that the modified rheological agent is synthesized from the modified monomer, ammonium persulfate, methacrylic acid, methoxypolyethylene glycol and glycerol monostearate in a weight ratio of 1.5:0.05:0.06:0.005:0.001;

[0122] The preparation method of the modified monomer comprises the following steps:

[0123] The modified monomer is obtained by mixing diethylene glycol dibenzoate, propionamide and bis-decanedioic acid in a mass ratio of 1:0.06:0.02 for 1.5 hours, then adding sodium hypophosphite under an argon atmosphere, and then performing hydrothermal reaction at 175 DEG C for 22 hours and dehydration at 95 DEG C for 50 minutes; wherein the mass ratio of diethylene glycol dibenzoate: propionamide: bis-decanedioic acid: sodium hypophosphite is 2:0.06:0.02:0.03.

[0124] The preparation method of the modified rheological agent comprises the following steps:

[0125] 1) mixing the modified monomer, ammonium persulfate and methacrylic acid with water for 3 hours to obtain a mixed solution A;

[0126] 3) mixing methoxypolyethylene glycol and glycerol monostearate with water to obtain a mixed solution B, then adding the mixed solution A dropwise into the mixed solution B and reacting for 3 hours, and then adjusting the pH to 7 to obtain the modified rheological agent;

[0127] The mass percentage of water in the mixed solution A is 35%; the mass percentage of water in the mixed solution B is 94%.

[0128] Example 11

[0129] The difference between this example and example 2 is that in step S1, the mixing method is to mix sintered magnesia, fused magnesia-alumina spinel, high-purity fused magnesia, active magnesia-alumina spinel micro powder, lanthanum oxide micro powder and binder at a rotation speed of 450 r / min, and every 3 min during the mixing process, 2 / 5 of the chlorinated paraffin is sprayed until the spraying of chlorinated paraffin is completed.

[0130] Example 12

[0131] The difference between this example and example 2 is that in step S1, the mixing method is to mix sintered magnesia, fused magnesia-alumina spinel, high-purity fused magnesia, active magnesia-alumina spinel micro powder, lanthanum oxide micro powder and binder at a rotation speed of 500 r / min, and every 5 min during the mixing process, 1 / 5 of the chlorinated paraffin is sprayed until the spraying of chlorinated paraffin is completed.

[0132] Example 13

[0133] The difference between this example and example 2 is that in step S2, the rotation speed of the mixing is 550 r / min; the spraying rate is 350 m / s.

[0134] Example 14

[0135] The difference between this example and example 2 is that in step S2, the rotation speed of the mixing is 650 r / min; the spraying rate is 450 m / s.

[0136] Example 15

[0137] The difference between this example and example 2 is that in step S1, 1 / 2 of the sintered magnesia, 1 / 2 of the fused magnesia-alumina spinel, 1 / 2 of the high-purity fused magnesia, 1 / 2 of the active magnesia-alumina spinel micro powder and 1 / 2 of the binder are taken, and in step S2, the remaining 1 / 2 of the sintered magnesia, the remaining 1 / 2 of the fused magnesia-alumina spinel, the remaining 1 / 2 of the high-purity fused magnesia, the remaining 1 / 2 of the active magnesia-alumina spinel micro powder and the remaining 1 / 2 of the binder are taken.

[0138] Example 16

[0139] The difference between the present embodiment and embodiment 2 is that in step S1, 2 / 3 of the sintered magnesia, 2 / 3 of the fused magnesia-alumina spinel, 2 / 3 of the high-purity fused magnesia, 2 / 3 of the active magnesia-alumina spinel micropowder, and 1 / 2-2 / 3 of the binder are taken, and in step S2, the remaining 1 / 3 of the sintered magnesia, the remaining 1 / 3 of the fused magnesia-alumina spinel, the remaining 1 / 3 of the high-purity fused magnesia, the remaining 1 / 3 of the active magnesia-alumina spinel micropowder, and the remaining 1 / 3 of the binder are taken.

[0140] Embodiment 17

[0141] The difference between the present embodiment and embodiment 2 is that in step S3, the pressing pressure of the working powder block 1 is 45 MPa, and the pressing pressure of the heat-insulating powder block 2 is 30 MPa.

[0142] Embodiment 18

[0143] The difference between the present embodiment and embodiment 2 is that in step S3, the pressing pressure of the working powder block 1 is 50 MPa, and the pressing pressure of the heat-insulating powder block 2 is 40 MPa.

[0144] Embodiment 19

[0145] The difference between the present embodiment and embodiment 2 is that in step S3, the four-time superimposed pressing method is as follows: the first time, the pressure is 55 MPa, and the heating temperature is 185℃; the second time, the pressure is 110% of the first time, i.e. 60.5 MPa, and the heating temperature is 205℃; the third time, the pressure is 120% of the second time, i.e. 72.6 MPa, and the heating temperature is 220℃; the fourth time, the pressure is 70% of the third time, i.e. 50.82 MPa, and the heating temperature is 195℃.

[0146] Embodiment 20

[0147] The difference between the present embodiment and embodiment 2 is that in step S3, the four-time superimposed pressing method is as follows: the first time, the pressure is 60 MPa, and the heating temperature is 195℃; the second time, the pressure is 115% of the first time, i.e. 69 MPa, and the heating temperature is 200℃; the third time, the pressure is 125% of the second time, i.e. 86.25 MPa, and the heating temperature is 210℃; the fourth time, the pressure is 75% of the third time, i.e. 64.69 MPa, and the heating temperature is 200℃.

[0148] Embodiment 21

[0149] The difference between the present embodiment and embodiment 2 is that in step S3, before each pressing of the four-time superimposed pressing, the joint surface of the working powder block 1 and the heat-insulating powder block 2 is subjected to corona treatment for 15 s, and the power of the corona is 4 kW.

[0150] Embodiment 22

[0151] The difference between this embodiment and embodiment 2 is that, in step S3, the joint surface of the working powder block 1 and the heat insulation powder block 2 is subjected to corona treatment for 20 s before each of the four times of pressing.

[0152] Example 23

[0153] The difference between this embodiment and embodiment 2 is that, in step S4, the drying method is: first drying at a vacuum degree of 75 Pa and a temperature of 80 ℃ for 3 h, and then air cooling drying at 30 ℃ for 2 h.

[0154] Example 24

[0155] The difference between this embodiment and embodiment 2 is that, in step S4, the drying method is: first drying at a vacuum degree of 80 Pa and a temperature of 60 ℃ for 4 h, and then air cooling drying at 20 ℃ for 2.5 h.

[0156] Example 25

[0157] The difference between this embodiment and embodiment 2 is that, in step S4, the dried composite brick is fired at 1300 ℃ for 12 h.

[0158] Example 26

[0159] The difference between this embodiment and embodiment 2 is that, in step S4, the dried composite brick is fired at 1400 ℃ for 14 h.

[0160] Experimental example

[0161] For each of the heat insulation composite bricks of the embodiments, 5 sample pieces of each embodiment are taken to test the heat insulation performance and deformation resistance of the heat insulation composite bricks, and the test results of the 5 sample pieces of each embodiment are averaged to be the test results of the embodiment, and the specific exploration is as follows:

[0162] 1. The influence of the raw material ratio of the heat insulation composite brick on the heat insulation performance and deformation resistance of the heat insulation composite brick. Table 1: Thermal conductivity (W / m.K) and bending strength (MPa, 200 ℃ x 24 h) of the heat insulation composite bricks in examples 1, 3-10 and comparative example 1

[0163] Group Example 1 Example 3 Example 4 Example 5 Example 6 Thermal conductivity 0.8 1.2 0.9 1.3 1.1 Flexural strength 67 64 66 60 61 Group Example 7 Example 8 Example 9 Example 10 Control Example 1 Thermal conductivity 0.9 1.0 1.3 1.1 2.3 Flexural strength 63 62 58 62 42

[0164] Comparative example 1 differs from example 1 in that no modified rheological agent is added;

[0165] As can be seen from table 1, the thermal conductivity of the heat insulation composite brick without adding a modified rheological agent is increased compared with examples 1, 2-10, and the bending strength is significantly reduced, so the modified rheological agent improves the heat insulation performance and deformation resistance of the heat insulation composite brick;

[0166] From comparative examples 1, 2-10, it can be seen that too small or too large proportion of the modified rheological agent, too small or too large proportion of hydrogenated polyether in the foamed microbeads, too small or too large proportion of aluminum oxide in the binding agent, and too small or too large preparation parameters of the modified rheological agent can all reduce the thermal conductivity and the bending strength of the thermal insulation composite brick.

[0167] 2, Effect of the preparation steps of the thermal insulation composite brick on the thermal insulation performance and the deformation resistance of the thermal insulation composite brick. Table 2 Thermal conductivity (W / m.K) and bending strength (MPa, 200℃x24h) of the thermal insulation composite bricks in examples 2, 11-26 and comparative examples 2-4

[0168]

[0169] Comparative example 2 differs from example 2 in that the parameters of the four times of superimposed pressing remain unchanged.

[0170] Comparative example 3 differs from example 2 in that no corona treatment is applied.

[0171] Comparative example 4 differs from example 2 in that only one layer of the working powder block and one layer of the thermal insulation powder block are stacked.

[0172] From the results in Table 2, it can be seen that comparative example 2 lacks the parameter changes of the four times of superimposed pressing, comparative example 3 lacks the corona treatment, and comparative example 4 lacks the multi-layer composite treatment, and the thermal conductivity and the bending strength of the thermal insulation composite bricks in comparative examples 2-4 are all significantly reduced compared with those in examples 2, 11-26, so the preparation steps of the present application are relatively more optimal.

[0173] From comparative examples 2, 11-26, it can be seen that too slow or too fast spraying rate of the chlorinated paraffin, too slow or too fast spraying rate of the mixed material B, too small or too large mixing ratio of the main raw materials in step S1 and step S2, too small or too large pressing pressure of the working powder block 1 and the thermal insulation powder block 2, too small or too large parameter changes of the fourth superimposed pressing, too small or too large corona parameters, and too small or too large drying parameters can all reduce the thermal conductivity and the bending strength of the thermal insulation composite brick, and the firing parameters of the composite brick in example 26 are larger, but the thermal conductivity and the bending strength of the thermal insulation composite brick are less improved compared with those in example 2, so from the economic point of view, the effect of example 2 is relatively more optimal.

Claims

1. A method for preparing a multilayer heat insulating composite brick for a rotary kiln against deformation, characterized in that, The raw material is composed of coarse aggregate, fine aggregate, auxiliary material and modified rheological agent, and the mass percentage of each component is: Fine aggregate: 11~15%, Auxiliary material: 3.8~6.7%, Modified rheological agent: 0.7~1%, Coarse aggregate: the rest; The coarse aggregate is composed of fused magnesium-aluminum spinel, fused magnesia, sintered magnesia in a mass ratio of 8~10:25~30:37.3~51.5; The fine aggregate is composed of active magnesium-aluminum spinel micro powder and lanthanum oxide micro powder in a mass ratio of 8~10:3~5; The auxiliary material is composed of chlorinated paraffin, foaming microbeads and binder in a mass ratio of 2~4:1~1.5:0.8~1.2; The modified rheological agent is synthesized from modified monomer, ammonium persulfate, methacrylic acid, methoxy polyethylene glycol and glycerol monostearate in a weight ratio of 1~1.5:0.05:0.06:0.005~0.009:0.001~0.002; The preparation method of the modified monomer comprises the following steps: After mixing diethylene glycol dibenzoate, propionamide and bis-decanoate for 1~1.5h, sodium hypophosphite is added under argon environment, and then hydrothermal reaction is carried out at 165~175℃ for 21~22h, and then dehydration is carried out at 85~95℃ for 40~50min to obtain the modified monomer; wherein the mass ratio of diethylene glycol dibenzoate: propionamide: bis-decanoate: sodium hypophosphite is 1~2:0.06:0.02:0.03; The preparation method of the modified rheological agent comprises the following steps: 1) mixing the modified monomer, ammonium persulfate, methacrylic acid and water for 2~3h to obtain a mixed solution A; 2) mixing methoxy polyethylene glycol, glycerol monostearate and water to obtain a mixed solution B, then adding the mixed solution A dropwise into the mixed solution B and reacting for 1~3h, and then adjusting the pH to 6~7 to obtain the modified rheological agent; The mass percentage of water in the mixed solution A is 35~37%, and the mass percentage of water in the mixed solution B is 94~96%; The preparation method of the composite brick comprises the following steps: S1, work material preparation: 1 / 2~2 / 3 of sintered magnesia, 1 / 2~2 / 3 of fused magnesium-aluminum spinel, 1 / 2~2 / 3 of high-purity fused magnesia, 1 / 2~2 / 3 of active magnesium-aluminum spinel micro powder, lanthanum oxide micro powder, chlorinated paraffin and 1 / 2~2 / 3 of binder are mixed uniformly to obtain a work material; S2, heat insulation material preparation: The remaining 1 / 3~1 / 2 of sintered magnesia, the remaining 1 / 3~1 / 2 of fused magnesium-aluminum spinel, the remaining 1 / 3~1 / 2 of high-purity fused magnesia, the remaining 1 / 3~1 / 2 of active magnesium-aluminum spinel micro powder and the remaining 1 / 3~1 / 2 of binder are mixed uniformly to obtain a mixed material A; foaming microbeads and modified rheological agent are mixed uniformly to obtain a mixed material B; the mixing speed is 550~650r / min; The mixed material B is sprayed into the mixed material A at a spraying rate of 350~450m / s, and the heat insulation material is obtained after spraying is completed; The mass ratio of the sintered magnesia, the fused magnesia-alumina spinel, the high-purity fused magnesia, the active magnesia-alumina spinel micropowder and the binder in step S1 to the same raw materials in step S2 is 1-2:

1. S3, pressing into a blank: The working raw materials are evenly divided into three parts, the heat insulation raw materials are evenly divided into two parts, and the three parts of working raw materials are pressed into working powder blocks (1), and the two parts of heat insulation raw materials are pressed into heat insulation powder blocks (2). Then, according to the stacking order of working powder block (1)-heat insulation powder block (2), four times of stacking and pressing are carried out to obtain a composite brick blank. The pressing pressure of the working powder block (1) is 45-50 MPa; the pressing pressure of the heat insulation powder block (2) is 30-40 MPa. Before each pressing of the four times of stacking and pressing, the bonding surface of the working powder block (1) and the heat insulation powder block (2) is subjected to corona treatment for 15-20 s, and the power of the corona is 4-6 kW. The method of the four times of stacking and pressing is: the first time, the pressure is 55-60 MPa, and the heating temperature is 185-195 DEG C; the second time, the pressure is 110-115% of the first time, and the heating temperature is 200-205 DEG C; the third time, the pressure is 120-125% of the second time, and the heating temperature is 210-220 DEG C; the fourth time, the pressure is 70-75% of the third time, and the heating temperature is 195-200 DEG C. S4, firing into a shape: The composite brick blank obtained in step S3 is dried to a water content of <0.4%, and then the dried composite brick blank is fired at 1300-1400 DEG C for 12-14 h to obtain a heat insulation composite brick after cooling to room temperature.

2. A method of manufacturing a deformation resistant multi-layered heat insulated composite brick for a rotary kiln as claimed in claim 1, wherein, The particle size of the foamed microbeads is 15-20 μm, and the foamed microbeads include, by weight fraction: 15-20 parts of hydrogenated polyether, 12-15 parts of azodicarbonamide and 1-2 parts of trimethylhexamethylene diamine.

3. A method of manufacturing a deformation resistant multi-layered heat shielding composite brick for a rotary kiln according to claim 1, characterized in that, The binder is calcium aluminate cement with a water content of 2.5-3.5 wt%, and the calcium aluminate cement includes, by mass percentage: 70-72% of aluminum oxide, 15-17% of calcium oxide, 10-13% of magnesium oxide, and the balance of silicon dioxide and iron oxide, wherein the mass ratio of silicon dioxide to iron oxide is 1:0.

8.

4. A method of manufacturing a deformation resistant multi-layered insulating composite brick for a rotary kiln as claimed in claim 1, wherein, In step S1, the mixing method is: the sintered magnesia, the fused magnesia-alumina spinel, the high-purity fused magnesia, the active magnesia-alumina spinel micropowder, the lanthanum oxide micropowder and the binder are mixed at a rotating speed of 450-500 r / min, and every 3-5 min during the mixing process, 1 / 5-2 / 5 of chlorinated paraffin is sprayed until the spraying of chlorinated paraffin is completed.

5. The method of claim 1, wherein the method further comprises: mixing the first and second materials to form a mixture; and heating the mixture to a temperature of about 1,000°C to about 1,500°C. 5 In step S4, the drying method is: first drying at a vacuum degree of 75-80 Pa and a temperature of 60-80 DEG C for 3-4 h, and then air cooling drying at 20-30 DEG C for 2-2.5 h.

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