JP3861130B2 - Spraying method for rotary kiln fireproof lining - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for spraying a rotary kiln refractory lining, and more particularly to a method for spraying a rotary kiln refractory lining used for manufacturing cement or incinerating waste.
[0002]
[Prior art]
A rotary kiln for waste incineration uses a wide variety of wastes such as municipal waste, sewage sludge, and industrial waste as fuel, and therefore has a wide range of temperature fluctuations and various atmospheres. Various waste materials are also used as fuel in rotary kilns for cement. For this reason, the fireproof lining of the rotary kiln is required to have characteristics such as chemical corrosion resistance, wear resistance, and thermal shock resistance.
[0003]
In order to satisfy these required characteristics, a fireproof lining having a low porosity and a high strength is required. For this reason, cast refractories that can be used for refractory linings of rotary kilns or refractory refractories with a low porosity are employed. The cast refractory can save labor in its construction work compared with the lining of the regular refractory, but currently, the construction method of the following procedure is adopted.
[0004]
That is, the inner wall surface of the rotary kiln is divided into approximately 20 to 20 divided wall surfaces in the circumferential direction, and the divided wall surface of the portion where the refractory lining is to be installed is disposed below the rotary kiln. The formwork is fixed to the iron skin (hereinafter referred to as the casing) of the rotary kiln at the location. Next, cast refractory clay is poured into the space surrounded by the casing and the formwork, and pouring is performed by applying vibration to the clay with a vibrator (step 1). In this case, if the number of divided wall surfaces is increased, the use of the inner mold (having a cylindrical surface) can be omitted, but the number of man-hours increases. On the other hand, if the number of divided wall surfaces is reduced, an inner formwork that forms the inner peripheral surface of the refractory after construction is indispensable.
[0005]
Next, when the first construction site is cured to some extent, the mold is removed, and the rotary kiln is rotated to move the next divided wall surface downward (step 2). The above-mentioned process 1 is repeated again, and the next division wall surface is constructed. Thereafter, Step 1 and Step 2 are repeated to construct the inner wall surface of the rotary kiln over the entire circumference.
[0006]
In this construction method, the waiting time until the cast refractory constructed in Step 1 is cured to some extent and the formwork can be removed is long (usually about 12 hours), and it is necessary to repeat the process by the number of divided wall surfaces. There is a problem that the time required for construction becomes very long.
[0007]
If the inner wall surface is also divided into the axial direction of the rotary kiln, the mold is also provided in the circumferential direction in step 1 above, poured into the first divided wall surface, and the cast refractory is cured after the mold is cured. Since it is necessary to repeat the process of performing the next pouring construction after fixing the formwork to the next divided wall surface, the time required for construction is further increased.
[0008]
When a fireproof lining is sprayed onto a rotary kiln, it is sufficient to provide a partition frame with a simple structure compared to a mold, so that there is an advantage that both labor saving and shortening of the construction period can be achieved as compared with the construction method by pouring. However, the conventional method of spraying refractories is to use dry powder clay or wet clay with no fluidity on an air stream and send it to the spray nozzle by piping. This is a method called dry or semi-wet in which moisture is injected at the location (Japanese Patent Laid-Open No. Sho 62-36070, etc.). Therefore, a sprayed refractory having a sufficiently small porosity (large bulk specific gravity), excellent strength and corrosion resistance Construction was not possible.
[0009]
That is, in the conventional spraying method, spraying is performed in a state where fine particles are not sufficiently dispersed in the clay, so that a large amount of air is taken into the clay and the porosity is large and the bulk specific gravity is small. Becomes a refractory. For this reason, even if it sprays on the inner wall surface of a rotary kiln, it cannot be used for the inner wall of a high temperature zone, the temperature at the time of use is comparatively low, and it is restricted to the construction of a part of inner wall which does not need corrosion resistance very much.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a fireproof lining spraying method capable of spraying all of the fireproof lining of a rotary kiln including the inner wall of the high temperature zone. is there.
[0011]
[Means for Solving the Problems]
The spray construction method of the rotary kiln refractory lining of the present invention, A powder composition containing a refractory aggregate, a refractory powder and a dispersant, is kneaded with water, and has a truncated cone shape with an upper end inner diameter of 50 mm, a lower end inner diameter of 100 mm, a height of 150 mm, and upper and lower ends opened. Pour into the cone type, and when the cone type is extracted upward and left to stand for 60 seconds, the spread diameter is 165 mm or more Self-flowing irregular refractory clay is pumped to the spray nozzle placed inside the rotary kiln by a pump and pump, and compressed air and quick setting agent are injected into the clay near the spray nozzle. However, it is characterized by spraying dredged soil on the inner wall surface including the high temperature zone of the rotary kiln.
[0012]
In the spray construction method of the present invention, since the clay having self-fluidity kneaded by adding water to the irregular refractory composition is pumped to the spray nozzle with the pump and pump, the spray construction is performed. The dispersion state of fine particles contained in the dredged soil is good, and the refractory having a low porosity and a large bulk specific gravity can be sprayed by having less air trapped in the dredged soil during the spraying. Since a refractory with a small porosity and a large bulk specific gravity can be sprayed, even if it is used for a refractory lining in a high temperature zone of a rotary kiln, it shows the same durability as an amorphous refractory by conventional casting construction.
[0013]
This self-fluiding clay Is Therefore, mixing the required amount of moisture in advance will make the water distribution in the clay even, so that it can be added to the clay before injecting compressed air. There is almost no air accompanying the surroundings of the particles, and most of the air bubbles that are involved when compressed air is injected into the clay as a carrier are released to the outside of the clay during spraying. Become a body.
[0014]
The fluidity of dredged soil can be evaluated using a cone type. That is, the clay immediately after adding water and kneading is poured into a cone-shaped cone shape having an upper end inner diameter of 50 mm, a lower end inner diameter of 100 mm, a height of 150 mm, and upper and lower ends opened, and the cone type is extracted upward and left for 60 seconds. The spread diameter when placed (the average value obtained by measuring the spread in two directions, hereinafter referred to as the flow value). The clay exhibits self-fluidity when the flow value is 165 mm or more. However, the flow value of the clay is preferably 180 mm or more so that the clay kneaded by the pressure feed pump and the pressure feed pipe can be sent to the construction site easily and without clogging. The measurement of fluidity is completed within 3 minutes after kneading using water at about 20 ° C. in a room at about 20 ° C.
[0015]
The reason why the rapid setting agent is injected into the clay in the vicinity of the spray nozzle is to harden the clay sprayed on the wall surface so that it does not flow down on the wall surface. The rapid setting agent is a powdered material such as sodium aluminate. It is preferred to inject things into the clay with compressed air. According to the spraying construction method of the present invention, even if the wall surface to be constructed is a vertical wall or a generally vertical curved surface, it can be sprayed without problems, and compared to the conventional dry or semi-dry spraying method, The amount of dust scattered is significantly less.
[0016]
In addition, although the injection | pouring location to the clay of the quick setting agent may be the same location as compressed air, Preferably it is set as the downstream of the injection port of compressed air. The quick setting agent is injected for the purpose of rapidly hardening the clay, and since it is a quick setting agent that rapidly hardens the clay, the pressure resistance of the clay in the piping does not increase due to the hardening of the clay. In addition, the place where the quick setting agent is injected into the clay is near the spray nozzle.
[0017]
As the quick-setting agent to be injected into the clay, an aqueous solution quick-setting agent can also be used, but it is preferable to use a powder to reduce the porosity of the construction body by keeping the amount of water in the clay to be sprayed to the minimum necessary. Is used. The powder quick setting agent is preferably injected into the clay from the quick setting agent inlet using compressed air as a carrier. It is preferable to use a concentrated aqueous solution as much as possible when injecting the aqueous setting agent into the clay. The rapid setting agent is preferably blown with compressed air so that the rapid setting agent is uniformly dispersed in the clay and injected into the clay as a carrier.
[0018]
The quick setting agent includes alkali metal aluminates such as sodium aluminate and potassium aluminate, carbonates such as sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, sodium sulfate, potassium sulfate and magnesium sulfate. Sulfate, CaO / Al ₂ O _Three , 12CaO · 7Al ₂ O _Three , CaO.2Al ₂ O _Three 3CaO · Al ₂ O _Three 3CaO.3Al ₂ O ・ CaF ₂ , 11CaO · 7Al ₂ O _Three ・ CaF ₂ And one or more selected from calcium oxide aluminate, calcium oxide hydroxide, calcium hydroxide hydroxide, and a composite or mixture thereof can be preferably used.
[0019]
Among these quick setting agents, it is particularly preferable to use a sodium aluminate powder or an aqueous solution because it is easily available, inexpensive, and has excellent quick setting characteristics.
[0020]
The injection amount of the quick setting agent is preferably 0.05 to 3 parts by weight with respect to 100 parts by weight of the dry weight-based powder composition excluding water and the dispersant. If it is less than 0.05 parts by weight, even if it is a quick setting agent having a large effect, the rapid setting speed will be insufficient and the dredged clay will flow down, and if it is injected more than 3 parts by weight, it will rapidly It will be hardened and spraying will be difficult, and the performance as a refractory such as heat resistance and corrosion resistance will decrease.
[0021]
Moreover, although it is preferable to carry out construction sequentially for each divided wall surface obtained by providing a partition frame on the inner wall surface to be constructed, there is no need for a mold for forming the inner peripheral surface of the inner wall like a cast refractory. Even when a partition frame is provided and construction is performed for each divided wall surface, a small number of partition frames may be used, and the number of steps may be reduced by the number of divided wall surfaces. Further, when spraying a small rotary kiln, a fireproof lining may be sprayed without providing any partition on the inner wall surface.
[0022]
In the preferable fireproof lining spraying method of the present invention, the inner wall surface is divided into a plurality of divided wall surfaces in the circumferential direction by a long partition frame parallel to the rotation axis of the rotary kiln, and sprayed for each divided wall surface. If the inner wall surface is divided into a plurality of divided wall surfaces, the size of the divided wall surfaces can be selected according to the amount of dredged soil that can be supplied at one time and the work time that can be continuously sprayed. Therefore, when constructing a large rotary kiln, it is preferable to divide the inner wall surface. If a partition frame with the same height as the thickness of the fireproof lining to be installed is provided around the dividing wall, the thickness of the fireproof lining under construction can be measured while constructing, and the fireproof lining of uniform thickness can be measured. Spray construction is easy.
[0023]
When the wide inner wall of a rotary kiln is constructed with an integrated fireproof lining, the inner refractory heated to a high temperature during its operation is extraneous because the temperature is higher than the refractory and iron skin on the cold iron skin side. Thermal expansion. For this reason, a 2 to 3 mm wide cut called a score line from the surface of the refractory lining is placed in the axial direction with a diamond saw for expansion, but a 2 to 3 mm thick partition frame such as a plywood plate is blown first. If spraying is applied in a state where it is attached to the boundary with the divided wall, the partition frame will be burned off during use, resulting in expansion allowance, and the work of removing the partition frame or cutting with a diamond saw can be omitted.
[0024]
According to a preferred fireproof lining spraying method of the present invention, the inner wall surface is divided into four or six divided wall surfaces in the circumferential direction by a long partition frame parallel to the rotation axis of the rotary kiln, and the divided wall surfaces facing each other are divided. Place them at approximately the same height and spray each one, then rotate the rotary kiln approximately 90 ° when dividing it into four divided walls, and approximately 60 ° when dividing it into six divided walls Rotate and spray the remaining divided walls one after another. When the inner wall surface is partitioned in the circumferential direction and sprayed for each divided wall surface, the number of divided wall surfaces is preferably four or six. If it divides | segments into this number, spraying construction should just be performed with respect to the substantially perpendicular | vertical wall surface with easy work, and the frequency | count of rotating a rotary kiln 90 degrees or 60 degrees at the time of construction can be reduced to 1 time or 2 times, respectively.
[0025]
If the rotary kiln is to be sprayed by changing the spraying conditions in the high temperature zone and the low temperature zone, or if it is inappropriate to construct a very long divided wall at once, the inner wall of the rotary kiln is It is preferable that the circumferential partition frame is also divided into a plurality of divided wall surfaces in the rotational axis direction and sprayed for each divided wall surface.
[0026]
In addition, if at least a part of the refractory lining that is sprayed onto the inner wall surface of the high-temperature zone is a multi-layered structure of a heat-insulating refractory lining with a high porosity and a refractory lining with a low porosity, an iron skin surrounding the high-temperature zone (casing) ) Can be prevented from overheating, and thermal energy can be used effectively. In this case, a heat-insulating refractory lining having a high porosity is applied to the iron skin side, and a fire-resistant lining having a low porosity is applied to the inner peripheral side.
[0027]
In the preferred fireproof lining spraying method of the present invention, the apparent porosity of the fireproof lining having a small porosity applied to at least the inside of the inner wall of the high temperature zone is 14% or less. In order to construct a fireproof lining with a low porosity, the amount of water in the dredged soil with self-fluidity may be reduced. If a refractory material having a small apparent porosity and a large bulk specific gravity can be sprayed, the refractory lining is good.
[0028]
A preferred fireproof lining spraying method of the present invention is based on 100 parts by weight of a dry-based powder composition in which the clay of an irregular refractory is composed of a refractory powder containing a refractory aggregate and alumina cement. It is assumed that 12 parts by weight or less of water is mixed. The mixing amount of water in the clay varies depending on the bulk specific gravity, porosity and particle size distribution of the refractory aggregate, and the composition of the refractory powder. 4 to 10 parts by weight per 100 parts by weight of the product. If the clay satisfies this configuration, a clay with good self-fluidity can be obtained, and the clay can be easily pumped to the spray nozzle with a piston-type pump and a pressure feed pipe. A construction body with a small apparent porosity can be obtained by spraying construction while injecting compressed air and a rapid setting agent into the clay.
[0029]
As fireproof aggregates, alumina, bauxite, diaspore, mullite, van earth shale, chamotte, quartzite, wax, kyanite, pyrophyllite, sillimanite, andalusite, chromium ore, spinel, magnesia, zirconia, zircon, One or more selected from carbon such as chromia, silicon nitride, aluminum nitride, silicon carbide, boron carbide, and graphite, titanium boride, and zirconium boride are preferable.
[0030]
As refractory powder, alumina cement, alumina, titania, bauxite, diaspore, mullite, van earth shale, chamotte, quartzite, pyrophyllite, sillimanite, andalusite, chrome ore, spinel, magnesia, zirconia, zircon, chromia, One having at least one selected from amorphous silica such as silicon nitride, aluminum nitride, silicon carbide, boron carbide, titanium boride, zirconium boride and fumed silica and having an average particle size of 30 μm or less is preferable.
[0031]
As a part of these refractory powders, when using an ultrafine refractory powder having an average particle diameter of alumina of 10 μm or less, preferably 5 μm or less, and an average particle diameter of fumed silica or the like of 10 μm or less, preferably 1 μm or less. The amount of water in the clay can be reduced, and good fluidity can be imparted to the clay.
[0032]
If alumina cement is used as a part of the refractory powder, the alumina cement functions as a binder for the amorphous refractory, and the construction body can maintain strength in a wide range from room temperature to high temperature.
[0033]
As the dispersant, it is preferable that a powdery material selected according to the kind of the refractory powder and the refractory aggregate to be used is blended in the powder composition. The dispersant is preferably at least one selected from polymetaphosphates, polycarboxylates, polyacrylates and β-naphthalenesulfonates, and the total amount of the refractory powder and the refractory aggregate in the powder composition It is preferable to add 0.02 to 1 part by weight with respect to 100 parts by weight.
[0034]
Since a commercially available product can be obtained as the pressure pump, it is preferable to use a piston type or squeeze type pressure pump. The squeeze type refers to a diaphragm type pump that drives a diaphragm with compressed air, a pump that squeezes a clay by squeezing an elastic tube with a roller, and the like. As these pumps, it is preferable to use a pump having a plurality of diaphragms, a plurality of tubes, or a plurality of pistons so that the pulsation of the clay to be pumped is reduced.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Below, the example of embodiment of the spray construction method of the rotary kiln fireproof lining of this invention is demonstrated with reference to drawings.
[0036]
FIG. 1 is a cross-sectional view of a rotary kiln refractory lining with a cut surface perpendicular to the rotary axis of the rotary kiln for explaining an example of a spray construction method.
[0037]
First, as shown in FIG. 1A, partition frames 31, 32, 33, and 34 are attached to the inner wall surface of a cylindrical casing (hereinafter referred to as a casing) 1 of a rotary kiln at a pitch of approximately 90 degrees in the circumferential direction. Divided wall surfaces 21, 22, 23, 24 that are equally divided into four are formed. The partition frames 31, 32, 33, 34 may be made of iron plate or wooden, and are appropriately fixed to an anchor (not shown) attached to the casing 1.
[0038]
Thereafter, as shown in FIG. 1 (B), the base 5 is installed in the longitudinal direction of the casing 1 as a scaffold for spraying, and the divided wall surface 21 and the partition frame in the kiln longitudinal direction partitioned by the partition frames 31 and 32 are used. Fireproof linings 41 and 42 are sprayed onto the divided wall surface 23 in the longitudinal direction of the rotary kiln partitioned by 33 and 34, respectively.
[0039]
Further, after the refractory linings 41 and 42 are hardened, the frame 5 is removed without removing the partition frames 31, 32, 33, 34, or after being removed, and the casing 1 is rotated 90 ° (main) by a rotary kiln rotating means (not shown). In an embodiment, it rotates (clockwise).
[0040]
Next, the gantry 7 shown in FIG. 1 (C) is installed in the longitudinal direction of the casing 1 as a scaffold, and consists of circumferential end surfaces after the partition frames 31, 32, 33, 34 or the refractory linings 41 and 42 are cured. The fireproof linings 43 and 44 are sprayed and applied to the divided wall surfaces in the kiln longitudinal direction sandwiched between the joint surfaces 6 of the sprayed body.
[0041]
In the present embodiment, since the spraying position is substantially at the rising position of the casing 1, the rebound loss at the time of spraying is small, and the workability of the operator who operates the spraying nozzle is also good. Furthermore, since the inner wall surface of the casing is equally divided into four in the circumferential direction, the rotary kiln can be rotated only once until the spraying is completed.
[0042]
Furthermore, in the present embodiment, the inner wall surface of the casing is equally divided into four in the circumferential direction. However, the present invention is not limited to this, and can be implemented in six divisions, eight divisions, or the like.
[0043]
In this embodiment, when fireproof lining is sprayed on the longitudinal dividing wall surface of the rotary kiln, at least one striking surface or partition frame burned out in the direction of the rotation axis or a score line is provided. It is preferable because the difference in thermal expansion between the refractory lining and the casing generated when the kiln is heated can be reduced, and cracks generated after the kiln is heated can be stopped. Here, when dividing | segmenting to a rotating shaft direction, what is necessary is just to install a partition frame in the circumferential direction. The score line may be cut with a diamond cutter or the like (usually about 1/3 of the thickness of the surface of the refractory lining) in the refractory lining after curing.
[0044]
In addition, a heat insulating spraying material with a high porosity and a low thermal conductivity is applied to the casing side, and the circumferential side is applied with a fireproof lining with a low porosity, or a multi-layer structure to provide a heat insulating property. It can also be granted. In this case, first, the fireproof linings 41 and 42 in FIG. 1B are formed in a multilayer structure in the thickness direction, and first, a heat insulating spray material is sprayed to a predetermined thickness, and then a fireproof lining with a low porosity is sprayed. That's fine. Next, the rotary kiln is turned 90 °, and the fireproof linings 43 and 44 in FIG. 1C may be similarly constructed in a two-layer structure or a multilayer structure.
[0045]
Here, when spraying to a multilayer structure, after spraying a heat-insulating spray material, the partition frames 31, 32, 33, 34 are shifted in the circumferential direction by about 100 mm to 200 mm to spray the fireproof lining. By doing so, it is preferable to bend the joint surface, and this can prevent the rotary kiln from being damaged due to a gap in which the joint surface communicates and the casing overheating.
[0046]
As the heat insulating spray material, a known dry or semi-wet spray refractory material may be used. Can be less. When it is desired to keep the temperature of the casing particularly low, it is preferable that a multilayer structure is formed in the radius (thickness) direction, and a heat-insulating amorphous refractory having a small thermal conductivity is sprayed on the outer peripheral portion.
[0047]
FIG. 2 is a view showing an example of a construction apparatus used in the spray construction of the rotary kiln refractory lining of the present embodiment.
[0048]
This construction apparatus includes a pressure feed pump 8, a pressure pump introduction hopper 8 a, pressure feed pipes 9 a, 9 b, 9 c, a taper pipe 10, a spray pipe 11, a spray nozzle 12, a quick setting agent addition device 13, and a compressed air inlet 14. , A compressed air flow valve 15 a, a compressed air pipe 15 b, a quick setting agent inlet 16, and a quick setting agent transport hose 17.
[0049]
First, a predetermined amount of water is added to a powder composition put into a mixer (not shown) and kneaded to obtain a clay. This clay is put into the charging hopper 8 a of the pressure feeding pump 8 and is pumped by the pressure feeding pump 8.
[0050]
Compressed air is injected into the clay pumped by the pump 8 after passing through the pumping pipes 9 a and 9 b and the taper pipe 10 at the position of the compressed air inlet 14.
[0051]
A compressed air pipe 15b connected to a compressed air supply source (not shown) is connected to the compressed air inlet 14, and the flow rate is controlled by a compressed air flow valve 15a to adjust the amount of compressed air injected. The dredged soil filled with the compressed air passes through the pressure-feeding pipe 9c, and the quick setting agent is injected into the quick setting agent injection port 16 and rapidly loses its self-fluidity, and is sprayed with properties suitable for spraying. The nozzle 12 is sprayed onto each divided wall surface of the rotary kiln.
[0052]
The quick setting agent addition device 13 and the quick setting agent injection port 16 are connected by a quick setting agent transport hose 17, and the powdery quick setting agent whose flow rate is adjusted to a predetermined amount is transported by air. The quick setting agent adding device 13 is optimally based on an air conveyance system using a rotary feeder. In this embodiment, a compressed air system (not shown) is connected to the quick setting agent adding device 13.
[0053]
In addition, when air-transporting powdery quick-setting agent, if moisture is adsorbed to the powder, it will adhere to the piping and cause clogging, so the quick-setting agent is transported with dry air through an air dehumidifier. It is desirable to perform. In addition, when a liquid quick setting agent is used, a diaphragm pump or a plunger pump may be connected instead of the quick setting agent adding device 13.
[0054]
In the present embodiment, the pressure feed pump 8 and the quick setting agent addition device 13 are arranged outside the rotary kiln main body, piped to the inside of the rotary kiln with the pressure feed pipe 9a, and further to the pressure feed pipe 9b made of a pressure hose or the like. Connect inside. Thus, the operation of the spray nozzle 12 inside the rotary kiln can be freely performed manually.
[0055]
In the construction method of the present invention, dredging of dredged soil, rebound, and generation of dust are significantly reduced during spray construction, and the construction yield and work environment are markedly higher than those of conventional irregular refractory spray construction methods. In addition, it is only necessary to install a partition frame that can be easily attached to the mold during the pouring method, and it is possible to save labor and shorten the construction period.
[0056]
【Example】
In the following examples, a concrete pump BSA702 made by Putzmister, which has two pistons, was used as the pressure feed pump 8. Furthermore, a Q gun manufactured by Japan Publico Co., Ltd. equipped with a table feeder was used as the quick-setting agent adding device 13 for quantitatively injecting the powder quick-setting agent into the clay. Further, the pumping speed of the pump 8 was adjusted to 3 tons / hour with the kneaded clay. The air supply pressure to the compressed air inlet 14 and the quick-set agent inlet 16 is 3 to 6 kg / cm, respectively. ² 2-5kg / cm ² As appropriate, the spraying was performed on the inner wall surface of the rotary kiln.
[0057]
In addition, in the spray construction apparatus used in the present embodiment, the pressure feed pipe 9a from the pressure feed pump 8 to the compressed air inlet 14 is a steel pipe having a dimension of 65A and a length of 30 m, and 9b having a dimension of 65A and a length of 65m. A 15 m pressure hose and a taper pipe 10 communicating with the 15 m taper steel pipe having a length of 1 m narrowed from 65 A to 50 A, and a pressure feed pipe 9 c from the compressed air inlet 14 to the quick setting agent inlet 16 have a length of 50 A A 10 m rubber hose was used, and the spray pipe 11 from the quick setting agent inlet 16 to the spray nozzle 12 was connected as a rubber hose having a dimension of 50 A and a length of 1 m so that there was no step inside the pipe. A Y-tube was attached to each of the compressed air inlet 14 and the quick setting agent inlet 16. In addition, the shape of the compressed air inlet 14 and the quick setting agent inlet 16 is not necessarily limited to a Y-shaped tube.
[0058]
As fireproof aggregate, Al ₂ O _Three And SiO ₂ With 13 wt% coarse particles having a particle size of 1.68 to 5 mm, 21 wt parts of medium particles having a particle size of 0.1 to 1.68 mm, respectively. Al ₂ O _Three And SiO ₂ 10 weight parts of coarse particles having a particle size of 1.68 to 5 mm, 15 weight parts of medium particles of 0.1 to 1.68 mm, respectively. Al ₂ O _Three And SiO ₂ 29% by weight of fine particles having an average particle size of 0.02 mm with bauxite aggregates of 89% by weight and 7% by weight, respectively.
[0059]
As refractory powder constituting the joint of refractory, Al ₂ O _Three And CaO content of 74 wt% and 24 wt%, respectively, 4 parts by weight of alumina cement with an average particle size of 5.6 μm, Al ₂ O _Three 3 parts by weight of buyer alumina having a 99.6% by weight content and an average particle size of 4.3 μm, SiO 2 ₂ 5 parts by weight of fumed silica having a content of 93% by weight and an average particle size of 0.8 μm was used.
[0060]
Furthermore, with respect to 100 parts by weight of the total amount of the above refractory aggregate and refractory powder, P ₂ O _Five And Na ₂ 0.1 parts by weight of powdered sodium tripolyphosphate having an O content of 58% by weight and 42% by weight, respectively, was added to the powder composition as a dispersant.
[0061]
Refractory aggregate, refractory powder and dispersant are mixed to form a powder composition, and 6.8 parts by weight of water is added to the powder composition with respect to 100 parts by weight of refractory aggregate and refractory powder. In addition, the mixture was kneaded for 3 minutes in a 500 kg capacity vortex mixer to form clay. The fluidity of each kneaded material is determined by pouring each kneaded material immediately after kneading into a truncated cone-shaped cone mold having an upper end inner diameter of 50 mm, a lower end inner diameter of 100 mm, a height of 150 mm and an upper and lower ends opened, and the cone mold is extracted upward. Measured with calipers in two directions at a position of 90 degrees with respect to the maximum diameter and the minimum diameter of the spread diameter when allowed to stand for 2 seconds, and the average value of the measured flow value is 240 mm, which is sufficient self-fluidity and pumpability Had.
[0062]
The quick setting agent is a powder having a particle size of 800 μm or less and an average particle size of about 150 μm, and containing sodium aluminate (including about 20% crystal water) and sodium carbonate in a weight ratio of 3: 1. Was added by the quick-setting agent adding device 13 so that the content of the refractory aggregate and the refractory powder was 0.3 parts by weight with respect to 100 parts by weight. That is, using the spray construction apparatus of FIG. 2, spray construction was performed to a thickness of about 200 mm on a steel wall imitating the inner wall surface of the rotary kiln.
[0063]
After spraying on the wall surface, a sample having a size of about 30 cm × 30 cm × 15 cm was taken from the construction body left for 24 hours under a temperature of about 20 ° C., and the collected sample was dried at 110 ° C. for 24 hours. Next, when the apparent porosity and bulk specific gravity of this sample were measured according to the method defined in JIS-R2205, they were 12% and 2.50, respectively. This value is 12%, which is the apparent porosity and bulk specific gravity determined for a construction body obtained by casting the same clay kneaded for 3 minutes in a mixer into a mold having an inner size of 4 cm × 4 cm × 8 cm. It is almost the same as 49.
[0064]
As can be seen from the above results, according to the spray construction method of the rotary kiln refractory lining of the present invention, the porosity and bulk specific gravity value of the obtained construction body are cast and the porosity of the construction body of the amorphous refractory. Compared with the value of bulk specific gravity, there is no inferiority. Since the corrosion resistance, which is an important use characteristic of refractory, is greatly influenced by the apparent porosity of the refractory, if the spray construction method of the refractory lining for rotary kiln of the present invention is adopted, the irregular refractory that has been cast is applied. It is possible to spray and apply an amorphous refractory having excellent corrosion resistance, which is inferior to that of the construction body, to the inner wall surface of the rotary kiln.
[0065]
【The invention's effect】
According to the spray construction method of the rotary kiln refractory lining of the present invention, compared to the construction method by pouring, it is only necessary to use a simple partition frame, and it is possible to achieve remarkable labor saving by eliminating the need for a formwork. Since it cures quickly, there is an advantage that the construction period can be remarkably shortened. In addition, this refractory lining spray construction body has significantly superior refractory characteristics compared to the construction of an amorphous refractory with a low bulk specific gravity by the conventional spray construction method. Suitable for construction.
[0066]
Furthermore, since the loss due to rebound during spraying is very small, the construction yield of the irregular refractory is good, and the dust is hardly generated, so the working environment is also good. Labor saving and ensuring a good working environment are also indispensable conditions for the survival and development of the industry in the future, so the industrial value is enormous.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in a direction perpendicular to a rotation axis for explaining an example of a method for spraying a rotary kiln refractory lining according to the present invention.
FIG. 2 is a schematic view showing an example of a construction apparatus used in the spray construction method for a rotary kiln refractory lining according to the present invention.
[Explanation of symbols]
1 ... Casing
5, 7 ... Mount
6 ... Joint surface
8 ... Pressure pump
8a ... Pumping hopper of pressure pump
9a, 9b, 9c ... pressure feeding piping
10 ... Tapered piping
11 ... Blowing piping
12 ... Spray nozzle
13 ... Quick setting agent addition device
14 ... Compressed air inlet
15a ... Flow valve for compressed air
15b ... compressed air piping
16 ... Quick setting agent inlet
17 ... Quick setting agent transport hose
21, 22, 23, 24 ... division wall surface
31, 32, 33, 34 ... partition frame
41, 42, 43, 44 ... Fireproof lining

Claims (7)

A powder composition containing a refractory aggregate, a refractory powder and a dispersant, is kneaded with water, and has a truncated cone shape with an upper end inner diameter of 50 mm, a lower end inner diameter of 100 mm, a height of 150 mm, and upper and lower ends opened. Poured into a corn mold, and when the corn mold was pulled out and left standing for 60 seconds, a self-flowing irregular refractory clay with a diameter of 165 mm or more was placed inside the rotary kiln by a pump and pump. It is pumped to the spray nozzle placed and injected with compressed air and quick setting agent into the clay near the spray nozzle, and sprayed to the inner wall surface including the high temperature zone of the rotary kiln. The rotary kiln fireproof lining spraying method.   The spray construction method according to claim 1, wherein the inner wall surface is divided into a plurality of divided wall surfaces in a circumferential direction by a long partition frame parallel to the rotation axis of the rotary kiln, and spraying is performed for each divided wall surface. For the rotation axis direction inner wall surface in the circumferential direction of the partition frame of the rotary kiln partition into a plurality of divided wall, spray construction method according to claim 2 Symbol placement for spraying installation for each partition wall surface. The blowing according to any one of claims 1 to 3 , wherein at least a part of the refractory lining applied to the inner wall surface of the high temperature zone has a multilayer structure of a heat-resistant lining having a high porosity and a refractory lining having a low porosity. Installation method. The spray construction method according to any one of claims 1 to 4, wherein the refractory powder includes a refractory ultrafine powder having an average particle diameter of 10 µm or less .   The spray construction method according to any one of claims 1 to 5, wherein the apparent porosity of the refractory lining applied to at least the inner side of the inner wall of the high temperature zone is 14% or less.   The clay of the amorphous refractory is a mixture of 12 parts by weight or less of water with respect to 100 parts by weight of a dry-based powder composition comprising a refractory powder containing a refractory aggregate and alumina cement. The spraying construction method in any one of claim | item 1 -6.

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