JP7351180B2 - Method for adjusting distribution width of discharge falling position in rotary kiln, and method for manufacturing rotary kiln - Google Patents

Description

TECHNICAL FIELD The present invention relates to a "method for adjusting the distribution width of discharged material falling positions in a rotary kiln" and a "method for manufacturing a rotary kiln." Specifically, the present invention relates to a method for adjusting the width of the distribution of falling positions of discharged materials in a rotary kiln, the purpose of which is to appropriately adjust the width of the distribution of falling positions of discharged materials discharged from a discharge port in a rotary kiln, and the method thereof. The present invention relates to a method for manufacturing a rotary kiln in which the width of the distribution of the falling positions of discharged materials is appropriately adjusted.

Conventionally, a rotary kiln equipped with a hollow cylindrical rotary furnace has been widely used in a series of processes for producing zinc oxide ore by recovering zinc from zinc-containing ores such as steel dust. This rotary kiln is a rotary heating furnace that has a cylindrical kiln body, and this kiln body is normally installed at a downward slope of about 1 to 4% from the input port to the discharge port of the material to be processed. ing.

In the above-mentioned rotary kiln, the material to be processed is inputted from the input port of the kiln main body, and is fired in the rotary kiln by a heat source such as a burner provided near the discharge port side. The material to be treated is gradually moved toward the discharge port side while being rolled and stirred through the main body of the kiln, which rotates around the central axis in the long axis direction, and is discharged as high-temperature waste (sintered material). It is discharged in a manner that it falls from the discharge port. The discharged high-temperature waste is normally transferred to the next process by a conveying device such as a pan conveyor installed below the discharge port.

As described above, it is sometimes required to reduce the width of the distribution of falling positions of high-temperature waste discharged from the discharge port of a rotary kiln, for example, from the viewpoint of preventing spillage from the conveyance device. On the other hand, in order to reduce the risk of damage to the conveyor device due to concentration of the falling position of the waste in a localized area, adjustments are required in the direction of increasing the width of the distribution of the falling position of the waste. There is also.

As a means of adjusting the width of the distribution of the falling position of the discharged materials in a rotary kiln, for example, a ``short cylinder that can be driven independently of the kiln body'' is additionally installed at the bottom of the rotary kiln's discharge port. A rotary kiln has been proposed that has a structure in which the width of the distribution of falling positions is adjusted by rotating the rotary kiln in any direction at any speed independently of the rotation of the rotary kiln (see Patent Document 1).

Japanese Unexamined Patent Publication No. 49-130422

The rotary kiln disclosed in Patent Document 1 requires the additional installation of a "short cylinder that can be driven independently of the kiln body", which is not provided in rotary kilns with a general structure. Therefore, the technology disclosed in this document is difficult to apply to existing rotary kilns. Furthermore, even when installing a new rotary kiln, it is impossible to avoid an increase in the initial installation cost due to the necessity of additionally installing the above-mentioned special structure.

The present invention was developed in view of the above situation. That is, the present invention is a means for adjusting the distribution width of the falling position of the discharged material from the discharge port of a rotary kiln, which is applicable to existing rotary kilns, and which is more effective than conventionally known means. The purpose is to provide technical means that can be implemented at low cost.

The inventors of the present invention have proposed that the exhaust gas discharged from the outlet of the rotary kiln can be improved by appropriately adjusting the chamfered dimensions of the corner formed by the side end surface and the inner peripheral surface of the cylinder at the outlet of the rotary kiln body. It was discovered that the width of the distribution of falling positions of objects in the width direction perpendicular to the central axis of the kiln body can be optimized, and the present invention was completed. More specifically, the present invention provides the following.

(1) A method for adjusting the width of the distribution of falling positions of discharged materials in a rotary kiln, in which the width of the distribution of falling positions of discharged materials from the discharge port in the width direction perpendicular to the central axis of the cylindrical kiln body is narrowed. In the case where the chamfer dimensions of the chamfered portion formed by chamfering the corner formed by the side end surface and the inner circumferential surface of the kiln main body at the discharge port are enlarged, and the width of the distribution of the falling positions of the discharged material is widened; This is a method for adjusting the distribution width of discharged material falling positions, which reduces the chamfer size.

According to the method (1) for adjusting the distribution width of the position where the discharged material falls from the rotary kiln, it is possible to appropriately adjust the width of the distribution of the position at which the discharged material falls from the discharge port of the rotary kiln. Thereby, the discharged material can be dropped in a desired manner onto the structure installed below the discharge port. Furthermore, since this method does not require the installation of any new structural parts, it can be applied to existing rotary kilns and can be implemented at lower cost than conventionally known means.

(2) The kiln main body includes a hollow cylindrical metal shell and a refractory attached to the inner peripheral surface of the metal shell, and only the portion made of the refractory is chamfered. The method for adjusting the distribution width of discharged matter falling positions according to (1), wherein the chamfered portion is formed by:

The adjustment method (2) can be applied to existing rotary kilns very easily, since the adjustment method described in (1) can be performed only by treating the part made of refractory material that is easy to process.

(3) The method for adjusting the distribution width of discharged material falling positions according to (2), wherein the refractory is a monolithic refractory.

According to the adjustment method (3), the adjustment method described in (2) can be performed more easily and efficiently.

(4) The method for adjusting the width of the distribution of the falling positions of discharged materials according to any one of (1) to (3), wherein the temperature of the discharged materials at the time of discharge from the discharge port is 900° C. or higher.

According to the adjustment method (4), from the perspective of maintaining the efficiency of equipment maintenance work, in operational sites where high temperature waste is discharged, adjustment of the width of the distribution of the falling position of waste is more urgently required. By enjoying the above-mentioned effects of the adjustment method described in any one of (1) to (3), it is possible to improve the efficiency of such on-site maintenance work.

(5) The rotary kiln further includes a sieve device installed below the discharge port, and the sieve device includes a plurality of metal sieves so that a plurality of slits are formed in a direction perpendicular to the width direction. The method for adjusting the width of the distribution of falling positions of excreta according to any one of (1) to (4), wherein the rod-shaped members are arranged in parallel.

According to the adjustment method (5), by appropriately adjusting the width of the distribution of the falling position of high-temperature waste (sintered material) with respect to the sieving device installed below the discharge port of the kiln main body, It is possible to reduce the risk of early damage to the sieve surface due to concentration of falling sintered material on a specific rod-shaped member forming the sieve surface. Furthermore, it is possible to prevent the range of falling positions of the waste from expanding beyond the sieve surface.

(6) The rotary kiln is a rotary kiln for reduction roasting used in the production of zinc oxide ore by the Werz process, or a rotary kiln for dry heating, and the discharged material is clinker after reduction roasting, or The method for adjusting the distribution width of the falling position of the discharged material according to any one of (1) to (5), which is zinc oxide ore after being dried and heated.

According to the adjustment method (6), a factory or the like that manufactures zinc oxide ore by the Wertz method can enjoy the above effects of the adjustment method described in any one of (1) to (5), and produce zinc oxide ore. It can contribute to improving the productivity of ores.

(7) The chamfer size is 3% or less of the outer diameter of the kiln body in the direction parallel to the central axis, and 3% or less of the outer diameter in the direction perpendicular to the central axis, (1 ) to (6).

According to the adjustment method (7), it is possible to maintain the width of the distribution of the falling positions of high-temperature waste (sintered material) at a certain level or more, thereby causing local concentration of the falling positions of the sintered material. It is possible to reduce the risk of early damage to various devices due to

(8) The chamfer size is made larger than 3% of the outer diameter of the kiln body in at least one of a direction parallel to the central axis and a direction perpendicular to the central axis; (1) The method for adjusting the width of the distribution of falling positions of discharged materials according to any one of (6) above.

According to the adjustment method (8), it is possible to narrow the width of the distribution of falling positions of high-temperature waste (sintered material) to a certain level or more, and thereby, for example, reduce the size of the surface that receives the sintered material. Even when it is not possible to secure a sufficient amount, unnecessary dispersion of the falling position of the sintered material can be suppressed.

(9) The discharge fall position distribution width according to any one of (1) to (6), wherein the chamfer size is adjusted to 0 in both a direction parallel to the central axis and a direction perpendicular to the central axis. Adjustment method.

According to the adjustment method (9), it is possible to maximize the width of the distribution of the falling positions of high-temperature waste (sintered material), and thereby the local concentration of the falling positions of the sintered material mentioned above can be achieved. It is possible to minimize the risk of early damage to various devices due to

(10) A method for manufacturing a rotary kiln, the method comprising: adjusting the distribution of the falling position of the waste from the discharge port in the width direction perpendicular to the central axis of the cylindrical kiln body; In the discharge falling distribution adjustment step, when narrowing the width of the distribution of the falling positions of the discharge, a corner formed by a side end surface and an inner circumferential surface of the kiln body at the discharge port is A method for manufacturing a rotary kiln, which performs a chamfer size adjustment process in which the chamfer size is reduced when the chamfer size of a chamfered part formed by chamfering is expanded to widen the distribution width of the falling position of the discharged material.

According to the manufacturing method (10), it is possible to obtain a rotary kiln in which the width of the distribution of the falling positions of the discharged material from the discharge port is appropriately adjusted in advance. Furthermore, this method does not require the installation of any new structural parts other than those included in a typical rotary kiln, so it can be implemented at low cost.

(11) The kiln main body includes a hollow cylindrical metal shell and a refractory attached to the inner peripheral surface of the metal shell, and in the chamfer size adjustment process, the refractory is removed from the refractory. The method for manufacturing a rotary kiln according to (9), wherein the chamfered portion is formed by chamfering only the portion where the chamfer is formed.

In the manufacturing method (11), the chamfering process in the manufacturing method described in (10) can be easily performed only by processing a portion made of a refractory material that is easy to process.

(12) The method for manufacturing a rotary kiln according to (11), wherein the refractory is a monolithic refractory, and the chamfer is formed by pouring the monolithic refractory into a mold having a predetermined shape.

According to the manufacturing method (12), the manufacturing method described in (11) can be carried out more easily and efficiently.

According to the present invention, there is provided a means for adjusting the width of the distribution of the falling position of the discharged material from the discharge port of a rotary kiln, which is easily applicable to an existing rotary kiln, and which is a conventionally known means. It is possible to provide technical means that can be implemented at a lower cost.

1 is a drawing schematically showing the overall configuration of a rotary kiln to which the present invention is applied. By applying the present invention, an example of a rotary kiln in which a chamfer is not provided (the chamfer dimension is adjusted to 0) at the corner formed by the side end surface and the inner circumferential surface of the discharge port of the kiln main body is provided. FIG. 3 is a cross-sectional view schematically showing the shape of the vicinity of the exit. The shape of the vicinity of the discharge port is schematically shown in an example of a rotary kiln in which a chamfered portion is provided at the corner formed by the side end surface and the inner circumferential surface of the discharge port of the kiln body according to the present invention. FIG. FIG. 3 is a diagram schematically showing a manner of falling from the discharge port of the rotary kiln shown in FIG. 2. FIG. 4 is a diagram schematically showing a manner of falling from the discharge port of the rotary kiln shown in FIG. 3. FIG. 4 is a graph diagram showing the distribution of falling positions of discharged materials in each of the rotary kilns shown in FIGS. 4A and 4B. 1 is a drawing schematically showing the operation of a rod-shaped member (grizzly bar) of a sieve device suitably arranged in a rotary kiln to which the present invention is applied. FIG. 2 is a drawing for explaining the configuration of a test facility when a reduction test using a cold model was conducted to confirm the effects of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of embodiments of the present invention will be described below. The present invention, that is, the "method for adjusting the distribution width of the discharge falling position in a rotary kiln" and the "method for manufacturing a rotary kiln" is applicable to a rotary kiln for reduction roasting used in the production of zinc oxide ore by the Wertz process, or a rotary kiln for dry heating. It can be preferably applied to rotary kilns. The discharge from these rotary kilns is clinker after reduction roasting or zinc oxide ore after drying and heating, and both reach a temperature of 900° C. or higher at the time of discharge. However, the present invention is a particularly effective technique when the temperature of the discharge from the rotary kiln is such a high temperature. However, the present invention is not limited to the above-described specific embodiments. In addition to the above, this technology can be widely applied to various types of rotary heating furnaces that discharge high-temperature waste from the discharge port.

<Rotary kiln>
Hereinafter, the structure and function of a rotary kiln 10, which is an example of a preferable application of the present invention, will be explained with reference to the drawings as appropriate.

[overall structure]
The rotary kiln 10 includes a cylindrical kiln main body 1, a main body support part that rotatably supports the kiln main body 1, a drive part that applies rotational force to the kiln main body 1, and a side of the discharge port 13. This is a large rotary heating furnace that is installed in the kiln body 1 and includes a heating burner (none of which is shown) that can heat the inside of the kiln body 1 to a high temperature.

The kiln main body 1 is installed at an angle from the input port (the right end in FIG. 1) of the material to be processed toward the discharge port 13 in such a manner that it can maintain a downward slope of usually about 1 to 4% with respect to the horizontal plane. . In the rotary kiln 10, while the kiln main body 1 rotates about its central axis along its long axis as a rotation axis, the workpieces are fed into the rotary kiln 10 through the input port, and the workpieces are fed down the kiln main body 1. It moves along the slope while being stirred and fired, and is discharged from the discharge port 13 as a high-temperature discharge (sintered material). For example, in the case of a large reduction roasting rotary kiln used for reduction roasting treatment of steel dust, etc., the inside of the kiln body 1 is heated to 1000°C to 1300°C. Further, the temperature of the discharged material (sintered material) at this time reaches 900° C. or higher.

The above-mentioned high-temperature discharged material is transferred to the next process by a conveying device 3 such as a pan conveyor, which is provided below the discharge port 13.

Furthermore, as shown in FIG. 1, the present invention provides a system for removing oversized lumps of waste at a position below the discharge port 13 and above the conveyance device 3 such as a bread conveyor. The sieving device 2 can be particularly preferably applied to the rotary kiln 10 installed therein. This sieving device 2 is preferably a sieve in which a plurality of metal bar-shaped members 21 are arranged in parallel so that a plurality of slits are formed parallel to the central axis of the kiln body 1. Further, more specifically, it is preferable that the sieving device 2 is a so-called swinging type roistle. The swinging rostle is a rod-shaped member 21 (see FIG. 6), also called a grizzly bar, whose end is connected to a disk eccentrically installed with respect to the central axis, and adjacent rod-shaped members (grizzly bars) 21 are connected to each other. This is a known sieving device that has a structure in which the sieving device repeatedly moves up and down in opposite directions.

[Kiln body]
The kiln main body 1 is not limited to a specific material or structure as long as it is a cylindrical pot with fire resistance. Further, as shown in FIG. 2, the kiln body 1 is composed of a metal shell 11 constituting its outer shell and a refractory 12 attached to the inner peripheral surface of the metal shell 11 and constituting its inner wall. It is preferable that the heating pot has a multi-layered structure. In the kiln main body 1 having such a structure, the chamfered portion 131 can be formed at the discharge port 13 by chamfering only the portion made of the refractory material 12 that is easy to process, without machining the metal shell 11. . Therefore, in this case, the present invention can be easily applied to an existing rotary kiln.

The metal shell 11 constituting the outer shell of the kiln main body 1 can be made of a hollow cylindrical metal member. A preferable metal material constituting the metal shell 11 may be one that satisfies various physical properties required for each individual rotary kiln in addition to heat resistance required depending on operating conditions. An example of such a preferable metal material is carbon steel.

As the refractory 12 forming the inner wall of the kiln body 1, for example, a monolithic refractory can be used. This monolithic refractory is not particularly limited as long as it is compatible with the chemical or thermal conditions of the sintered material to be discharged, and conventionally known castable refractories can be used as appropriate. As a preferable example, a castable refractory whose main component is Al ₂ O ₃ can be used as the refractory 12 forming the inner wall of the kiln body 1 .

[Sieving device]
The above-mentioned rocking type rooster, which is a preferred specific example of the sieving device 2, has a sieving surface that is constituted by a heat-resistant metal bar member (grizzly bar) 21 and has excellent wear resistance. As a result, it is possible to highly accurately prevent the retention, accumulation, and adhesion of waste materials such as powder that should be sieved below the sieve surface, and there are fewer problems such as clogging due to huge lumps remaining on the sieve surface. , huge lumps remaining on the sieve surface can be quickly discharged. In FIG. 1, among the sintered material 4 that is discharged from the discharge port 13, a sintered material lump 5 larger than the size that can be transported by the transporting device 3 is sieved by a sieving device (oscillating roistle) 2. It is schematically shown how the particles are separated by a rod-like member (grizzly bar) 21 and removed from the system. On the other hand, the sintered material 4 having a size that can be transported by the transport device 3 is transferred to the next process by the transport device 3 such as a pan conveyor.

In conventional sieving devices, the above-mentioned bar-like member (grizzly bar) 21 is usually provided with a wear-resistant protective cover on the side on which the discharged material constantly collides. When the temperature of the discharged material is relatively low, carbon steel, which is relatively inexpensive, can be used as the material for the wear-resistant protective cover. Carbon steel not only loses its strength at temperatures above 500°C, but also deteriorates due to thinning due to oxidation. On the other hand, the "method for adjusting the distribution width of the falling position of waste in a rotary kiln" of the present invention can alleviate the local collision of high-temperature waste by appropriately dispersing the falling distribution of high-temperature waste. Even if the temperature of the discharged material reaches 500°C, which causes a decrease in strength and thinning due to oxidation, the deterioration will not proceed immediately and become unusable, but the deterioration will be suppressed and the service life will be extended. be able to.

On the other hand, when zinc oxide sintered ore that has reached a high temperature of 900°C or higher is the discharged material, such as in the manufacturing process of zinc oxide ore by DRK, the above wear-resistant cover is made of high chromium cast iron. Preferably, the wear-resistant protective cover is made by bonding chromium-based wear-resistant plate materials with a chromium-based wear-resistant material. Alternatively, ceramic can also be used as the wear-resistant protective cover for the purpose of further improving heat resistance. In these cases as well, by appropriately widening the distribution of the falling positions of extremely high-temperature waste, local collisions of the waste can be alleviated as described above, and the bar-shaped member (grizzly bar) 21 can be Product life can be significantly extended.

<Method for adjusting the distribution width of the discharged material falling position in a rotary kiln>
The "method for adjusting the distribution width of the discharge position in a rotary kiln" (hereinafter also simply referred to as "method for adjusting the width of the distribution of the discharge position in the rotary kiln") of the present invention includes, for example, It is a process that aims to optimize the width of the distribution of positions.

The "discharge falling position distribution width adjustment method" of the present invention is performed by chamfering a corner 132 (see FIG. 2) formed by the side end surface and the inner circumferential surface of the discharge port of the kiln main body 1. This is a process of optimizing the distribution width of the falling position of the discharged material from the discharge port 13 by appropriately adjusting the chamfer dimensions (C1, C2) of the chamfered portion 131 (see FIG. 3).

[Adjustment of chamfer dimensions]
Here, the "chamfered part" in this specification is formed by a side parallel to the central axis of the kiln body 1 and a side perpendicular to the same central axis, such as the chamfered part 131 shown in FIG. This is the part including the slope obtained by cutting the corner 132 (see FIG. 2) at the hypotenuse of a right triangle whose angles formed by both sides are right angles.

In addition, the size of the "chamfer" is determined by the chamfer dimension C1 parallel to the central axis and the chamfer dimension C2 perpendicular to the central axis, as shown in Figure 3, as in the case of general chamfer processing. stipulated by. In this specification, "enlarging the chamfer dimension" means increasing at least either the chamfer dimension C1 parallel to the central axis or the chamfer dimension C2 perpendicular to the central axis. , means increasing the length of the hypotenuse of the above-mentioned right triangle forming the chamfer. On the other hand, "reducing the chamfer dimension" refers to reducing the length of the hypotenuse of the above-mentioned right triangle forming the chamfer by reducing at least either of the above-mentioned chamfer dimensions C1 or C2. shall mean.

There are no particular limitations on the means for forming the chamfered portion 131 of an appropriate size on the discharge port 13. For example, in the vicinity of the discharge port 13 of the kiln body 1, the existing refractory 12 may be removed as necessary, and then a chamfered portion 131 with a predetermined chamfer size may be formed in the area using a clay-like refractory. I can do it. Another method for forming the chamfered portion 131 at the outlet 13 with an appropriate size is to remove the existing refractory material 12, attach a formwork formed to a predetermined chamfer size, and then attach an unshaped refractory part to this. It is also possible to use a method of pouring things in. The former method is preferably carried out in conjunction with partial repair of the discharge port 13 of the kiln main body 1, which is generally carried out every two months. Further, the latter method is preferably carried out in conjunction with the periodic renewal of refractories, which is generally carried out every 6 months to 1 year.

Here, FIG. 3 shows the discharged waste discharged from the discharge port 13 of the kiln main body 1 in the rotary kiln 10 in which the chamfered portion 131 is formed by the "discharge falling position distribution width adjustment method in a rotary kiln" of the present invention. The manner in which it falls is shown. As shown in FIG. 3, in a rotary kiln having a chamfered portion 131, the discharged material passes over the slope formed by the chamfered portion 131 and falls from the end of the discharge port 13.

Note that FIG. 2 shows how the discharged material falls from the discharge port 13 in the rotary kiln 10 in which the chamfered portion 131 is not formed on the corner portion 132. Here, the rotary kiln 10 shown in FIG. 2 is shown as an example of a state in which the "method for adjusting the distribution width of discharged material falling position in a rotary kiln" of the present invention is not applied. Since this is an essential step to form the chamfered portion 131 with an appropriate size, if the appropriate size of the chamfered portion 131 is 0, the distribution of the discharged material falling position in the rotary kiln of the present invention As a result of appropriately applying the width adjustment method, the rotary kiln may take the form shown in FIG. 2.

Here, in a rotary kiln in which a chamfered portion 131 is formed at the discharge port 13 of the kiln body 1 as shown in FIG. 3, as the kiln body 1 rotates in the d direction, the discharge When an object passes through the slope of the chamfered portion 131, a slip c occurs in the circumferential direction toward the lowest point position on the inner circumferential surface of the kiln body 1. On the other hand, as shown in FIG. 2, in a rotary kiln in which the chamfered portion 131 is not formed at the discharge port 13 of the kiln main body 1, the above-mentioned slipping c of the discharged material cannot occur, as shown in FIG. 4A.

In a rotary kiln (FIG. 4B) in which a chamfered portion 131 is formed at the discharge port 13 of the kiln body 1, the width of the distribution of falling positions in the width direction perpendicular to the central axis of the kiln body 1 is increased due to the effect of this slip c. It has a width b shown in FIG. 4B. This width b is smaller than the width a of the same distribution of the rotary kiln shown in FIG. 4A in which the chamfered portion 131 is not formed. In fact, the distribution in the width direction of the falling positions of the discharged materials in the rotary kiln shown in FIGS. 4A and 4B is generally as shown in the graph of FIG. 5. In other words, by forming the chamfered part 131 on the corner part 132 by chamfering, slipping c is intentionally caused, thereby causing the flow from the discharge port 13 in the width direction perpendicular to the central axis of the kiln body 1. It is possible to reduce the width of the distribution of the positions where the discharged material falls.

Furthermore, there is a negative correlation between the size of the chamfered portion 131 and the width of the distribution of falling positions of the discharged material from the discharge port 13 due to the above-mentioned effect. In other words, by enlarging the chamfer dimension of the chamfered portion 131, the sliding width of the above-mentioned slip c can be expanded and the width of the distribution of the falling positions of the discharged material can be narrowed. By reducing , the width of the distribution of the falling positions of waste can be widened.

Here, for example, if it is desired to maximize the width of the distribution of the falling positions of the discharged materials by applying the present invention, the chamfer size of the chamfered portion 131 is minimized, that is, the chamfered size is set to 0 so that no chamfered portion is formed. It is possible to do so (Fig. 2, Fig. 4A). In this case, the present invention is implemented by adjusting the size of the chamfered portion to zero.

However, the discharge port 13 of the kiln body 1 is close to a heat source such as a heavy oil burner, and in addition, the residue of the input material to be processed is oxidized and generates heat in the vicinity of the discharge port 13. Among these, the corners of the outlet 13 are often required to be chamfered in order to suppress damage caused by heat failure, since this is a location subject to a particularly high heat load. In this case, first form a chamfer of the minimum size for the purpose of preventing the above-mentioned damage, and then further adjust the chamfer dimensions of the chamfer 131 as necessary, depending on the width of the target drop position distribution. You can make adjustments such as enlarging it.

In addition, as described above, in the rotary kiln 10 in which the sieving device 2 such as a swinging Rostr is installed, high-temperature waste (sintered material) is deposited in a partial area of the rod-shaped member (grizzly bar) 21 that constitutes the sieve surface. ) collides intensively, the wear is concentrated only on a specific part of the rod-like member (grizzly bar) 21, which shortens the frequency of replacement and reduces the efficiency of maintenance work. In such cases, the method of adjusting the width of the distribution of falling positions of discharged materials according to the present invention is very effective. Specifically, by suppressing both the chamfer dimensions C1 and C2 to about 3% or less of the outer diameter of the kiln body 1, the distribution of the falling position of the discharged material is widened, and a specific rod-shaped member (grizzly bar) is It is possible to avoid the concentration of high-temperature waste materials impinging on the grizzly bar 21, increase the frequency of replacement of the bar member (grizzly bar) 21, and improve the efficiency of maintenance work. In particular, when the chamfer dimensions C1 and C2 are both adjusted to 0, the width of the distribution of the falling positions of discharged objects is maximized, so that the efficiency of the maintenance work described above can be further improved.

<Rotary kiln manufacturing method>
The "rotary kiln manufacturing method" of the present invention is a process that can obtain a rotary kiln in which the width of the distribution of the falling position of the discharged material from the discharge port of the kiln body is appropriately adjusted. In this manufacturing method, the width of the distribution of the falling positions of the discharged material is adjusted by "chamfer size adjustment processing." A specific implementation method for this "chamfer size adjustment process" may be the same as the "chamfer size adjustment" in the above-mentioned "method for adjusting the distribution width of discharged material falling position in a rotary kiln".

<Cold model reduction test>
As shown above, in a rotary kiln, the influence of the size of the chamfered part of the outlet of the kiln body on the distribution of the falling position of the discharge from the outlet was confirmed by a cold model reduction test.

(No chamfered part)
First, a cold model 6 in which the size of the chamfered portion was 0 was created and tested. Specifically, as shown in FIG. 7, a steel pipe 61 having an outer diameter of φ300 mm and cut into a length of 1 m is tilted at a downward slope of 2% with respect to a horizontal plane, and while maintaining this state, the steel pipe 61 is The cold model 6 was created so as to be rotatably supported by four rollers 62 (two of the four rollers 62 are not shown) having a center axis parallel to the center axis. In conducting the test, a receiving paper 63 divided into three areas parallel to the central axis of the steel pipe 61 was provided 160 mm below the opening (assumed to be a discharge port) at the lower side end of the steel pipe 61. The container was rotated by hand at 3 to 5 rpm so that the rotation direction was d counterclockwise when facing the opening (discharge port) at the side end of the container.

Furthermore, the areas on the receiving paper 63 were divided as follows. First, with the horizontal position of the central axis of the steel pipe 61 as a reference, it was divided into two areas by a straight line parallel to the central axis. The area on the left side is defined as the first area 63A, and with respect to the area on the right side, two areas are further defined in a straight line parallel to the central axis based on a position moved 75 mm to the right from the horizontal position of the central axis. It was divided into Of the two divided regions, the left region was defined as a second region 63B, and the right region was defined as a third region 63C.

For the cold model 6 configured as above, zinc oxide ore (size distribution: 0.5 mm or more and less than 1 mm 20%, 1 mm or more and less than 3 mm 20%, 4 mm or more and 6 mm 1.5 kg of zinc content (zinc content: 65% by weight), 7 mm or more and less than 9 mm 10%, 10 mm or more and 10%, zinc content: 65% by weight) is moved to the lower side edge, discharged, and falls onto the receiving paper 63. I let it happen. They then videotaped the situation and analyzed the images.

(With chamfered part)
Next, regarding the chamfer dimensions ((C1) (C2)), the dimension (C1) in the direction parallel to the central axis is 27 mm (9% of the outer diameter of the steel pipe 61), and the dimension in the direction perpendicular to the central axis ( A cold model 6 was created in which a chamfered portion with C2) of 13.5 mm (4.5% of the outer diameter of the steel pipe 61) was formed. This chamfered portion was formed by joining a thin iron plate that was sloped so that the chamfer dimensions ((C1) (C2)) of the chamfered portion were the above-mentioned sizes to the outlet side of the steel pipe 61. The injection and discharge of zinc oxide ore and analysis of its behavior were conducted under the same conditions as above.

(Test results)
In the former cold model with a chamfered part, the waste fell over the entire width (75 mm) of the second region 63B, whereas in the latter cold model with a chamfered part, the waste fell across the first region 63A and the second region 63B. The discharge part fell concentrated at the boundary between the areas 63B and 2.

<Test operation using actual equipment>
Furthermore, in order to more specifically demonstrate the effects of the present invention, a test operation was conducted using an actual rotary kiln. This test operation was carried out in a dry heating rotary kiln (DRK) in which the kiln body, which has an outer diameter of 3300 mm and a total length of 31 m, is rotatably installed at a downward slope of 2.0% with respect to the horizontal plane. This was done by observing the difference in the distribution of the falling position of the discharged material when the chamfer dimensions of the chamfered portion were changed for each of the following Examples (Examples 1 to 3).

In addition, during this test operation, a swinging Roostor was installed as a sieving device 1.75 m below the discharge port of the rotary kiln, with a gap of 100 mm between the grizzly bars that constitute the sieving surface. When directly facing the rotary kiln's discharge port, this swing-type rooster is placed in the area to the right of the horizontal position of the central axis of the kiln body, and the left end of the sieve surface is placed in the area that is horizontal to the central axis of the kiln body. It was set to match. Furthermore, the grizzly bar constituting the sieve surface was arranged to be parallel to the central axis of the kiln body. Furthermore, a vertical wall was provided at the left end of the sieve surface to prevent the waste from falling into the area on the left with respect to the horizontal position of the central axis of the kiln body.

For the above-mentioned DRK and swing-type rostle, the heating of the heavy oil burner was adjusted so that the temperature at the time of discharge from the discharge port of the discharge section was 900°C, and the heating of the heavy oil burner was adjusted half-clockwise when the kiln body was directly facing the discharge port. It was rotated in the circumferential direction at 0.7 to 1.0 rpm. Then, the crude zinc oxide cake (moisture content: 20 mass% or more and 30 mass% or less, zinc content: 61 mass% or more and 68 mass% or less) is fed from the input port of the kiln body at a non-uniform speed of 8 t/h. Zinc oxide ore (size: approximately 1 mm or more and 6 mm or less, zinc content: 60 mass% or more and 70 mass% A test operation was continuously conducted in which the following materials were discharged from the discharge port and dropped onto the sieve surface of a swinging Rooster.

(Example 1: Chamfered part (large))
In the above DRK, the chamfer dimension of the discharge end of the kiln body is 300 mm (C1) in the direction parallel to the central axis (9.1% of the outside diameter of the kiln body), and the chamfer dimension in the direction perpendicular to the central axis. The chamfered portion was formed so that (C2) was 150 mm (4.59% of the outer diameter of the kiln body). The chamfering process to form the chamfered portion was performed by pouring the monolithic refractory into a mold. Incidentally, the method of chamfering was the same in each of the following Examples and Comparative Examples.

(Example 2: Chamfered part (small))
In the above DRK, the chamfer size (C1) of the discharge end of the kiln body is 100 mm (3.0% of the outside diameter of the kiln body), and the chamfer size (C2) is 100 mm (3.0% of the outside diameter of the kiln body). 0%).

(Example 3: No chamfered part)
In the above DRK, the chamfer dimensions (C1) and (C2) of the discharge end of the kiln body were both 0 mm. That is, no chamfered portion was formed.

(Test results)
In the test operation of Example 1 where the chamfer dimensions (C1) were 300 mm and (C2) 150 mm, the width of the distribution of the falling position of the discharged material was narrower, and specifically, zinc oxide ore was found at the left end of the sieve surface. The falls were concentrated near the first and second rows of grizzly bars, counting from the vertical wall that was set up at the location. As a result, the wear-resistant covers provided on the Grizzly bars in the first and second rows began to wear out to the extent that repairs were required after one month of use. Furthermore, as the product was continued to be used, the wear progressed further, and the amount of wear reached an amount that could not be repaired after 3 months of use.

In the test operation of Example 2 where the chamfer dimensions (C1) were 100 mm and (C2) 100 mm, the distribution of the falling position of the discharged material was wider than that in Example 1. The particles were almost evenly distributed and fell near the first to third rows of grizzly bars, counting from the vertical wall provided at the left end of the sieve surface. Compared to Example 1, it was confirmed that the sliding width of the discharged material on the chamfered portion was smaller, and the width of the distribution of the falling positions was wider.

In the test operation of Example 3 where the chamfer size (C1) was 0 mm and (C2) was 0 mm, that is, no chamfer was formed, the width of the distribution of the falling position of the discharged material was the largest, and the zinc oxide ore did not reach the sieve surface. It spread and fell throughout the constituent grizzly bars. As a result, the burden on the Grizzly bar was significantly reduced, and even after three months of use, the amount of wear remained repairable.

From the above test results, the present invention is a process that can be easily implemented on existing rotary kilns with only simple chamfering, but it has been found that It can be seen that this is a process in which the width of the distribution of can be arbitrarily adjusted.

1 Kiln body 11 Metal shell 12 Refractory 13 Discharge port 131 Chamfered portion 132 Corner 2 Sieving device 21 Rod-shaped member (Grizzly bar)
3 Conveyance device 4 Discharge (sintered material)
5 Exhaust material (sintered mass)
6 Cold model (rotary kiln)
61 Steel pipe 62 Roller 63 Receiving paper 10 Rotary kiln

Claims (11)

A method for adjusting the width of the distribution of falling positions of discharged materials in a rotary kiln, the method comprising:
When narrowing the width of the distribution of the falling positions of the discharged material from the discharge port in the width direction perpendicular to the central axis of the cylindrical kiln body, In the chamfered portion where the corner portion is chamfered in the entire circumferential direction of the discharge port , at least one of a chamfer dimension parallel to the central axis or a chamfer dimension perpendicular to the central axis. Enlarging the length of the slope of the chamfered portion (the distance between the inner circumference side end of the side end surface and the discharge port side end of the inner circumference surface) by enlarging one chamfer dimension,
In the case of widening the distribution of the falling positions of the discharged material , at least one of a chamfer dimension parallel to the central axis of the kiln body or a chamfer dimension perpendicular to the central axis in the chamfered part is selected. reducing the length of the slope by reducing one dimension ;
Method for adjusting the distribution width of the discharged material falling position. The kiln main body includes a hollow cylindrical metal shell and a refractory attached to the inner peripheral surface of the metal shell,
forming the chamfered portion by chamfering only the portion made of the refractory;
The method for adjusting the distribution width of the discharged matter falling position according to claim 1. the refractory is a monolithic refractory;
The method for adjusting the distribution width of the discharged matter falling position according to claim 2. The temperature at the time of discharge from the discharge port is 900 ° C. or more,
4. The method for adjusting the width of the distribution of falling positions of excreta according to any one of claims 1 to 3. The rotary kiln further includes a sieve device installed below the discharge port,
The sieving device includes a plurality of metal rod-shaped members arranged in parallel so that a plurality of slits are formed in a direction perpendicular to the width direction.
The method for adjusting the width of the distribution of falling positions of discharged substances according to any one of claims 1 to 4. The rotary kiln is a rotary kiln for reduction roasting used in the production of zinc oxide ore by the Werz process, or a rotary kiln for dry heating,
The discharged material is clinker after reduction roasting or zinc oxide ore after dry heating.
The method for adjusting the width of the distribution of falling positions of discharged materials according to any one of claims 1 to 5. The chamfer size is 3% or less of the outer diameter of the kiln body in the direction parallel to the central axis, and 3% or less of the outer diameter in the direction perpendicular to the central axis.
The method for adjusting the width of the distribution of falling positions of discharged materials according to any one of claims 1 to 6. The chamfer size is larger than 3% of the outer diameter of the kiln body in at least one of a direction parallel to the central axis and a direction perpendicular to the central axis.
The method for adjusting the width of the distribution of falling positions of discharged materials according to any one of claims 1 to 6. A method for manufacturing a rotary kiln, the method comprising:
comprising an exhaust fall distribution adjustment step of adjusting the width of the distribution of the fall position of the exhaust from the discharge port in the width direction perpendicular to the central axis of the cylindrical kiln main body,
In the discharge falling distribution adjustment step,
In order to narrow the width of the distribution of the positions where the discharged material falls, the corners formed by the side end surface and the inner peripheral surface of the kiln main body at the discharge port may be chamfered in the entire circumferential direction of the discharge port. In the chamfered portion, the length of the slope of the chamfered portion is increased by enlarging at least one of the chamfer dimensions parallel to the central axis or the chamfer dimensions perpendicular to the central axis. (distance between the end on the inner peripheral side of the side end surface and the end on the discharge port side of the inner peripheral surface),
In the case of widening the distribution of the falling positions of the discharged material , at least one of a chamfer dimension parallel to the central axis of the kiln body or a chamfer dimension perpendicular to the central axis in the chamfered part is selected. performing a chamfer dimension adjustment process of reducing the length of the slope by reducing one dimension ;
How to make a rotary kiln. The kiln main body includes a hollow cylindrical metal shell and a refractory attached to the inner peripheral surface of the metal shell,
In the chamfer size adjustment process, the chamfer is formed by chamfering only the portion made of the refractory;
The method for manufacturing a rotary kiln according to claim 9 . The refractory is an unshaped refractory,
forming the chamfered portion by pouring the monolithic refractory into a mold having a predetermined shape;
The method for manufacturing a rotary kiln according to claim 10 .

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