Refractory lining of rotary kiln and preparation method of refractory lining

Abstract

The invention relates to a refractory lining of a rotary kiln and a preparation method of the refractory lining, in particular to the field of rotary kilns, and the refractory lining comprises preforms and pouring bodies which are alternately arranged on the surface of the rotary kiln around the axial direction of the rotary kiln; a heat conduction partition plate is arranged between the pouring body and a kiln body of the rotary kiln. The thickness D of the heat conduction partition plate is larger than or equal to 30 mm and smaller than the thickness of the pouring body. The preform comprises the following components in percentage by mass: greater than or equal to 50% of Al2O3 and greater than or equal to 90% of Al2O3 + SiO2. The casting body comprises the following components in percentage by mass: greater than or equal to 50% of Al2O3 and greater than or equal to 90% of Al2O3 + SiO2. According to the refractory lining of the rotary kiln, the heat conduction and heat insulation plate and the pouring body are filled between the adjacent prefabricated bodies, the integrity, firmness and heat preservation performance of the masonry are guaranteed, the using condition that the masonry is in a vibration state for a long time is met, and it is guaranteed that the average temperature of the high-temperature section of the outer skin temperature of the kiln body is not higher than 150 DEG C.

Description

Technical Field

[0001] The present invention relates to the field of rotary kilns, and in particular to a refractory lining of a rotary kiln and a preparation method thereof. Background Art

[0002] The biggest feature of the rotary kiln refractory lining is that the refractory materials built in the kiln rotate with the kiln body and materials at high temperatures. The refractory materials are not only subject to thermal shock, erosion and wear from kiln gas and materials, but also have to withstand vibration stress, extrusion stress and torsion generated by the rotation of the kiln body.

[0003] Therefore, the lining of the kiln body is required to have sufficient strength. As a sodium-based roasting rotary kiln, the optimal roasting temperature of vanadium slag is <850℃, and the optimal range is required to be controlled at 800-850℃. The start-up and shutdown of the rotary kiln make the temperature change relatively frequently, which is bound to place high demands on the wear resistance and thermal shock resistance stability of the kiln lining refractory material.

[0004] At present, the most common masonry method for rotary kilns in China is shaped refractory brick masonry. The shaped refractory brick masonry process can reduce the kiln skin temperature in the following ways:

[0005] (1) Use composite bricks with lightweight layers or multi-layer masonry

[0006] During the production process, traditional masonry techniques, due to the lack of connection between bricks and the rotary kiln lining, lead to vertical and horizontal movement. Insulation measures are generally not taken, or a high-density, high-strength insulation layer is used to ensure a strong insulation layer. Otherwise, it is easy to cause crushing and pulverization due to squeezing and friction, resulting in kiln collapse accidents. This results in a high thermal conductivity coefficient of the insulation layer, resulting in poor insulation effect.

[0007] (2) Increase the thickness of refractory bricks

[0008] According to theoretical calculations, if the refractory bricks are thickened by 20mm, the kiln lining temperature will be reduced by about 10℃. However, the total weight of the kiln lining increases too much. It is unlikely to achieve a lower kiln lining temperature by continuing to use this masonry method. In addition, it will increase material costs, usage costs and reduce output.

[0009] (3) Lay insulation material under the shaped refractory bricks

[0010] Many manufacturers lay fiberboard (cotton) with low thermal conductivity under shaped bricks. The lower the thermal conductivity of the fiber product, the lower its density and strength. In the actual production process, the movement of shaped bricks in the kiln directly grinds and powders the insulation cotton (board), resulting in frequent brick dropping, low stability and short service life.

[0011] In summary, the refractory lining of the currently used rotary kiln still has defects such as poor thermal insulation effect and low strength due to design defects. Summary of the Invention

[0012] In view of the problems existing in the prior art, the purpose of the present invention is to provide a refractory lining of a rotary kiln and a preparation method thereof, so as to solve the defects of the refractory lining of the rotary kiln, such as poor thermal insulation effect resulting in a high outer skin temperature of the kiln body and low kiln body strength that is not conducive to long-term use.

[0013] To achieve this object, the present invention adopts the following technical solutions:

[0014] In a first aspect, the present invention provides a refractory lining for a rotary kiln, the refractory lining comprising: prefabricated bodies and cast bodies alternately arranged on the surface of the rotary kiln axially around the rotary kiln;

[0015] A heat-conducting partition is provided between the casting body and the kiln body of the rotary kiln;

[0016] The thickness D of the heat-conducting baffle is 30 mm ≤ D < the thickness of the casting body;

[0017] The preform contains the following contents by mass percentage: Al2O3≥50%, Al2O3+SiO2≥90%;

[0018] The casting body contains the following contents in percentage by mass: Al2O3≥50%, Al2O3+SiO2≥90%.

[0019] The refractory lining of the rotary kiln provided by the present invention ensures the integrity, firmness and thermal insulation of the masonry by using shaped low-thermal-conductivity insulation boards and cast bodies between adjacent prefabricated bodies, meets the use conditions of the masonry in a long-term shock state, ensures that the average temperature of the high-temperature section of the kiln shell temperature is not higher than 150°C, solves the problem of small bricks easily falling off during masonry, and greatly improves the equipment operation rate; at the same time, the reduction in the weight of the kiln lining also reduces the operating load of the equipment motor, which has the effect of saving power consumption.

[0020] As a preferred technical solution of the present invention, the prefabricated body is welded to the wall of the rotary kiln via embedded parts.

[0021] As a preferred technical solution of the present invention, the prefabricated body includes: an integrally formed prefabricated body and / or a prefabricated brick prefabricated body.

[0022] As a preferred technical solution of the present invention, the width of the prefabricated body is the same as the width of the cast body.

[0023] As a preferred technical solution of the present invention, the thickness of the preform = the thickness of the casting body + the thickness of the heat-conducting partition.

[0024] As a preferred technical solution of the present invention, the thickness of the preform is 210-240 mm.

[0025] In a second aspect, the present invention provides a method for preparing a refractory lining of a rotary kiln as described in the first aspect, the preparation method comprising:

[0026] Prefabricated bodies are built on the inner surface of the rotary kiln, and then the embedded parts of the prefabricated bodies are welded to the anchor nails on the surface of the rotary kiln. Slurry is then poured between adjacent prefabricated bodies to form a cast body, which is then cured to obtain a refractory lining.

[0027] As a preferred technical solution of the present invention, the embedded parts in the high temperature section of the rotary kiln are made of 1Cr18Ni9Ti.

[0028] Preferably, the embedded parts in the low temperature section of the rotary kiln are made of Q235.

[0029] As a preferred technical solution of the present invention, the material of the anchoring nails in the high temperature section of the rotary kiln is 1Cr18Ni9Ti.

[0030] Preferably, the material of the anchoring nails in the low temperature section of the rotary kiln is Q235.

[0031] As a preferred technical solution of the present invention, the masonry method includes alternate masonry on opposite sides.

[0032] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0033] The refractory lining provided by the present invention adopts a mixed masonry method of prefabricated bodies and cast bodies, and the prefabricated bodies in the kiln are fixed to the kiln shell with anchors. There is no problem of longitudinal and lateral movement, the compressive strength of the thermal insulation material is not restricted, and thermal insulation materials with low thermal conductivity can be selected as the thermal insulation layer, thereby improving the thermal insulation effect, greatly reducing the kiln skin temperature, and ensuring that the average temperature of the high-temperature section of the kiln shell temperature is not higher than 150°C, solving the problem of small bricks easily falling off during masonry, and greatly improving the equipment operation rate; at the same time, the reduction in the weight of the kiln lining also reduces the operating load of the equipment motor, thereby saving electricity consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of a refractory lining of a rotary kiln provided in an embodiment of the present invention.

[0035] In the figure: 100-casting body, 200-prefabricated body, 300-heat-conducting partition.

[0036] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0037] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0038] The refractory linings of the current rotary kilns still have defects such as poor thermal insulation and low strength due to design defects. Based on this, the present invention provides a refractory lining for a rotary kiln. By using shaped low-thermal-conductivity insulation boards and castable fillings between adjacent prefabricated bodies, the integrity, firmness and thermal insulation of the masonry are ensured, meeting the conditions for the masonry to be used in a long-term seismic state, and ensuring that the average temperature of the kiln outer skin in the high-temperature section does not exceed 150°C. The details are as follows:

[0039] This embodiment provides a refractory lining of a rotary kiln, such as Figure 1 As shown, the refractory lining includes: prefabricated bodies 200 and cast bodies 100 which are alternately arranged on the surface of the rotary kiln in an axial direction around the rotary kiln.

[0040] Wherein, a heat-conducting partition 300 is provided between the casting body 100 and the kiln body of the rotary kiln.

[0041] The thickness D of the heat-conducting baffle 300 is 30 mm ≤ D < the thickness of the casting body 100 .

[0042] Wherein, in the preform 200, the mass percentage content is: Al2O3≥50%, Al2O3+SiO2≥90%.

[0043] In the present invention, the physical and chemical indicators of the preform 200 include: compressive strength at 110°C × 24h ≥ 60MPa, flexural strength at 1100°C × 3h ≥ 65MPa, and bulk density ≥ 2.35g / cm 3 , the linear change rate of 1100℃×3h is ≤±00.5%, the refractoriness is ≥1790℃, and the thermal shock stability of water cooling at 1100℃ is ≥30 times.

[0044] The casting body 100 has the following contents by mass percentage: Al2O3≥50%, Al2O3+SiO2≥90%.

[0045] In the present invention, the physical and chemical indicators of the casting body 100 include: compressive strength at 110°C × 24h ≥ 60MPa, flexural strength at 1100°C × 3h ≥ 65MPa, and bulk density ≥ 2.35g / cm 3 , the linear change rate of 1100℃×3h is ≤±00.5%, the refractoriness is ≥1790℃, and the thermal shock stability of water cooling at 1100℃ is ≥30 times.

[0046] In the present invention, the remaining composition of the preform 200 and the casting body 100 can be reasonably designed and selected according to the corresponding physical and chemical indicators and the conventional requirements in the field.

[0047] The prefabricated body 200 is welded to the wall of the rotary kiln via embedded parts.

[0048] The prefabricated body 200 includes: an integrally formed prefabricated body 200 and / or a prefabricated brick prefabricated body 200.

[0049] In the present invention, the prefabricated body 200 is made of prefabricated bricks, which means that prefabricated bricks of a certain specification are laid with mortar. The specific size of the prefabricated bricks can be 500×202, 182×230, etc.

[0050] The width of the preform 200 is the same as the width of the casting body 100 .

[0051] The thickness of the preform 200 = the thickness of the casting body 100 + the thickness of the heat-conducting partition 300 .

[0052] The thickness of the preform 200 is 210-240 mm, for example, 210 mm, 215 mm, 220 mm, 225 mm, 230 mm, 235 mm or 240 mm, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0053] Furthermore, the present invention provides a process for preparing the aforementioned refractory lining, comprising:

[0054] Precast bodies 200 are built on the inner surface of the rotary kiln, and then the embedded parts of the precast bodies 200 are welded to the anchor nails on the surface of the rotary kiln. Then, slurry is poured between adjacent precast bodies 200 to form a casting body 100, which is cured to obtain a refractory lining.

[0055] Wherein, the material of the embedded parts in the high temperature section of the rotary kiln is 1Cr18Ni9Ti.

[0056] Wherein, the material of the embedded parts in the low temperature section of the rotary kiln is Q235.

[0057] In the present invention, the high temperature section of the rotary kiln refers to the temperature of 600-700°C, where vanadium pentoxide reacts with sodium salt to generate sodium vanadate soluble in water, and the reaction equation is: V2O5+Na2CO3→2NaVO3+CO2↑.

[0058] In the present invention, the low temperature section of the rotary kiln refers to the temperature between 500-600°C, where the binding phase fayalite is oxidized and decomposed. The reaction equation is: Fe2O3·SiO2→Fe2O3+SiO2.

[0059] Among them, the material of the anchoring nails in the high temperature section of the rotary kiln is 1Cr18Ni9Ti.

[0060] Among them, the material of the anchoring nails in the low temperature section of the rotary kiln is Q235.

[0061] Wherein, the masonry method includes alternate masonry on opposite sides.

[0062] In the present invention, the method of alternating masonry on opposite sides means that when the precast body 200 is laid, a part is first laid at the bottom of the rotary kiln, and then the rotary kiln is rotated and fixed, and a new precast body 200 is laid opposite to the precast body 200 that has been laid, and the laying is carried out in this way. This avoids damage to the kiln body due to uneven weight distribution when precast bricks are laid on one side, and prevents the kiln body from rotating freely due to unbalanced weight during construction, which may cause danger.

[0063] Furthermore, in order to illustrate the heat preservation effect that can be achieved by the refractory lining of a rotary kiln provided by the present invention, the following actual example is used for illustration, as follows:

[0064] Example 1

[0065] This embodiment provides a refractory lining for a rotary kiln, the refractory lining comprising: prefabricated bodies 200 and cast bodies 100 alternately arranged on the surface of the rotary kiln axially around the rotary kiln;

[0066] A heat-conducting partition 300 is provided between the casting body 100 and the kiln body of the rotary kiln;

[0067] The thickness D of the heat-conducting baffle 300 is 30 mm;

[0068] The preform 200 comprises Al2O3 at 50% by mass and Al2O3+SiO2 at 90% by mass.

[0069] The casting body 100 contains Al2O3 in a mass percentage ratio of 50% and Al2O3+SiO2 in a mass percentage ratio of 90%.

[0070] The prefabricated body 200 is welded to the wall of the rotary kiln through embedded parts;

[0071] The prefabricated body 200 is a prefabricated body 200 made of prefabricated bricks, and adjacent prefabricated bricks are connected by solidification using mortar;

[0072] The width of the preform 200 is the same as the width of the casting body 100;

[0073] The thickness of the preform 200 = the thickness of the casting body 100 + the thickness of the heat-conducting baffle 300;

[0074] The thickness of the preform 200 is 220 mm.

[0075] The preparation process is as follows:

[0076] Prefabricated bodies 200 are laid on the inner surface of the rotary kiln, and then embedded parts of the prefabricated bodies 200 are welded to anchor nails on the surface of the rotary kiln. Slurry is then poured between adjacent prefabricated bodies 200 to form a casting body 100, which is then cured to obtain a refractory lining.

[0077] The embedded parts are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln; the anchoring nails are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln;

[0078] The rotary kiln provided in this embodiment has good strength, and the average temperature of the outer skin of the kiln body in the high temperature section is no higher than 150°C.

[0079] Example 2

[0080] This embodiment provides a refractory lining for a rotary kiln, the refractory lining comprising: prefabricated bodies 200 and cast bodies 100 alternately arranged on the surface of the rotary kiln axially around the rotary kiln;

[0081] A heat-conducting partition 300 is provided between the casting body 100 and the kiln body of the rotary kiln;

[0082] The thickness D of the heat-conducting baffle 300 is 30 mm;

[0083] The preform 200 contains 60% Al2O3 and 95% Al2O3+SiO2 by mass percentage.

[0084] The casting body 100 contains Al2O3 in an amount of 60% by mass and Al2O3+SiO2 in an amount of 95% by mass.

[0085] The prefabricated body 200 is welded to the wall of the rotary kiln through embedded parts;

[0086] The preform 200 is an integrally formed preform 200;

[0087] The width of the preform 200 is the same as the width of the casting body 100;

[0088] The thickness of the preform 200 = the thickness of the casting body 100 + the thickness of the heat-conducting baffle 300;

[0089] The thickness of the preform 200 is 210 mm.

[0090] The preparation process is as follows:

[0091] Prefabricated bodies 200 are laid on the inner surface of the rotary kiln, and then embedded parts of the prefabricated bodies 200 are welded to anchor nails on the surface of the rotary kiln. Slurry is then poured between adjacent prefabricated bodies 200 to form a casting body 100, which is then cured to obtain a refractory lining.

[0092] The embedded parts are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln; the anchoring nails are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln;

[0093] The rotary kiln provided in this embodiment has good strength, and the average temperature of the outer skin of the kiln body in the high temperature section is no higher than 150°C.

[0094] Example 3

[0095] This embodiment provides a refractory lining for a rotary kiln, the refractory lining comprising: prefabricated bodies 200 and cast bodies 100 alternately arranged on the surface of the rotary kiln axially around the rotary kiln;

[0096] A heat-conducting partition 300 is provided between the casting body 100 and the kiln body of the rotary kiln;

[0097] The thickness D of the heat-conducting baffle 300 is 30 mm;

[0098] The preform 200 contains Al2O3 in an amount of 55% by mass and Al2O3+SiO2 in an amount of 90% by mass.

[0099] The casting body 100 contains Al2O3 in an amount of 55% by mass and Al2O3+SiO2 in an amount of 90% by mass.

[0100] The prefabricated body 200 is welded to the wall of the rotary kiln through embedded parts;

[0101] The prefabricated body 200 is a prefabricated body 200 made of prefabricated bricks, and adjacent prefabricated bricks are connected by solidification using mortar;

[0102] The width of the preform 200 is the same as the width of the casting body 100;

[0103] The thickness of the preform 200 = the thickness of the casting body 100 + the thickness of the heat-conducting baffle 300;

[0104] The thickness of the preform 200 is 240 mm.

[0105] The preparation process is as follows:

[0106] Prefabricated bodies 200 are laid on the inner surface of the rotary kiln, and then embedded parts of the prefabricated bodies 200 are welded to anchor nails on the surface of the rotary kiln. Slurry is then poured between adjacent prefabricated bodies 200 to form a casting body 100, which is then cured to obtain a refractory lining.

[0107] The embedded parts are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln; the anchoring nails are made of 1Cr18Ni9Ti in the high temperature section of the rotary kiln, and are made of Q235 in the low temperature section of the rotary kiln;

[0108] The rotary kiln provided in this embodiment has good strength, and the average temperature of the outer skin of the kiln body in the high temperature section is no higher than 150°C.

[0109] Comparative Example 1

[0110] The only difference from Example 1 is that the heat-conducting baffle 300 is not provided.

[0111] In this example, since the heat-conducting baffle 300 is not provided, the outer skin temperature of the kiln body in the high-temperature section increases significantly and can reach above 200° C., which is not conducive to efficient use of the energy efficiency of the rotary kiln.

[0112] Comparative Example 2

[0113] The only difference from Example 1 is that the casting body 100 is replaced by a preformed body 200 .

[0114] In this example, since the heat-resistant lining is constructed using prefabricated bodies 200, it may fall off due to process construction, equipment abnormalities, operation and thermal stress, mechanical stress damage, etc., affecting the normal operation of the rotary kiln.

[0115] Comparative Example 3

[0116] The only difference from Example 1 is that the preform 200 is replaced by the casting body 100 .

[0117] In this example, since the heat-resistant lining is formed by the casting body 100, although the heat-resistant lining is integrally formed with the casting body 100 as the thermal insulation lining, it is easily affected by thermal expansion and contraction during high-temperature use after integral molding, causing the heat-resistant lining to fail and fall off, affecting the normal operation of the rotary kiln.

[0118] Comparative Example 4

[0119] The only difference from Example 1 is that the mass percentage of Al 2 O 3 in the preform 200 is 40%.

[0120] In this example, since the Al 2 O 3 content of the preform 200 in the heat-resistant lining is relatively low, the preform 200 has poor fire resistance and corrosion resistance.

[0121] Comparative Example 5

[0122] The only difference from Example 1 is that the mass percentage of Al2O3+SiO2 in the preform 200 is 80%.

[0123] In this example, due to the low Al2O3+SiO2 content of the preform 200 in the heat-resistant lining, the lining has poor refractoriness, refractoriness under load and thermal conductivity, which is not conducive to ensuring the temperature of the rotary kiln.

[0124] Comparative Example 6

[0125] The only difference from Example 1 is that the mass percentage of Al 2 O 3 in the casting body 100 is 40%.

[0126] In this example, due to the low Al 2 O 3 content of the cast body 100 in the heat-resistant lining, the preform 200 has poor fire resistance and corrosion resistance.

[0127] Comparative Example 7

[0128] The only difference from Example 1 is that the mass percentage of Al 2 O 3 +SiO 2 in the casting body 100 is 80%.

[0129] In this example, due to the low Al2O3+SiO2 content of the cast body 100 in the heat-resistant lining, the lining's refractoriness, refractoriness under load temperature, and thermal conductivity are poor, which is not conducive to ensuring the temperature of the rotary kiln.

[0130] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0131] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0132] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A refractory lining for a rotary kiln, characterized in that: The refractory lining comprises: prefabricated bodies and cast bodies alternately arranged on the surface of the rotary kiln axially around the rotary kiln; A heat-conducting partition is provided between the casting body and the kiln body of the rotary kiln; The thickness D of the heat-conducting baffle is 30 mm ≤ D < the thickness of the casting body; The preform contains the following contents by mass percentage: Al2O3≥50%, Al2O3+SiO2≥90%; The casting body contains the following contents in percentage by mass: Al2O3≥50%, Al2O3+SiO2≥90%.

2. The refractory lining according to claim 1, wherein The prefabricated body is welded to the wall surface of the rotary kiln via embedded parts.

3. The refractory lining according to claim 1, wherein The prefabricated body includes: an integrally formed prefabricated body and / or a prefabricated brick prefabricated body.

4. The refractory lining according to claim 1, wherein The width of the preform is the same as the width of the casting body.

5. The refractory lining according to claim 1, wherein The thickness of the preform = the thickness of the casting body + the thickness of the heat-conducting partition.

6. The refractory lining according to claim 1, wherein The thickness of the preform is 210-240 mm.

7. A method for preparing a refractory lining of a rotary kiln according to any one of claims 1 to 6, characterized in that: The preparation method comprises: Prefabricated bodies are built on the inner surface of the rotary kiln, and then the embedded parts of the prefabricated bodies are welded to the anchor nails on the surface of the rotary kiln. Slurry is then poured between adjacent prefabricated bodies to form a cast body, which is then cured to obtain a refractory lining.

8. The preparation method according to claim 7, wherein The embedded parts in the high temperature section of the rotary kiln are made of 1Cr18Ni9Ti; Preferably, the embedded parts in the low temperature section of the rotary kiln are made of Q235.

9. The preparation method according to claim 7, wherein The material of the anchoring nails in the high temperature section of the rotary kiln is 1Cr18Ni9Ti; Preferably, the material of the anchoring nails in the low temperature section of the rotary kiln is Q235.

10. The preparation method according to claim 7, wherein The masonry method includes alternate masonry on opposite sides.

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