Method for reducing clogging in rotary kilns, heat treatment equipment

Abstract

To provide a blockage reduction method of a rotary kiln for reducing blockage of the rotary kiln.SOLUTION: The blockage reduction method of a rotary kiln has a scoop feeder between both ends in the longitudinal direction of the rotary kiln, and has a fusion preventing agent adding step of charging a fusion preventing agent into the rotary kiln via the scoop feeder.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for reducing clogging in a rotary kiln and to a heat treatment device. [Background technology]

[0002] Rotary kilns are used for drying and reducing ores, and for producing various ceramic materials such as cement (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-141719 A Summary of the Invention [Problem to be solved by the invention]

[0004] A rotary kiln has a roughly cylindrical shape, and typically, the raw material to be treated is loaded into one end, and heated from the other end by a heating means such as a burner. The rotary kiln is positioned so that the other end is lower, and as it rotates around the central axis, the loaded material is heated as it gradually moves toward the other end. The product obtained after the heat treatment is then discharged from an outlet provided at the other end.

[0005] When the temperature of the high-temperature region formed inside the rotary kiln by the heating means reaches the melting point of the material in the material to be treated, the material may adhere to the inner wall of the rotary kiln, forming a ring-shaped deposit. When such a ring-shaped deposit is formed, the material in the rotary kiln becomes difficult to flow, and the ring-shaped deposit grows, eventually leading to clogging and making it impossible to operate.

[0006] In view of the problems associated with the above-mentioned conventional techniques, one aspect of the present invention aims to provide a method for reducing clogging in a rotary kiln, which can reduce clogging in the rotary kiln. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present invention, The rotary kiln has a scoop feeder between both ends in the longitudinal direction thereof, and has a fusion inhibitor adding step of feeding a fusion inhibitor into the rotary kiln through the scoop feeder. death, The anti-fusing agent contains at least one selected from the group consisting of silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide. A method for reducing plugging in a rotary kiln is provided. Effect of the Invention

[0008] According to one aspect of the present invention, a method for reducing clogging of a rotary kiln can be provided, which can reduce clogging of the rotary kiln. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a heat treatment apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA' in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the form for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications and substitutions can be made to the following embodiment without departing from the scope of the present invention. [Methods to reduce clogging in rotary kilns] One method for suppressing the growth of ring-shaped deposits and preventing blockage of the rotary kiln is to add an anti-fusing agent when the formation of ring-shaped deposits is noticed.

[0011] Possible methods for adding the anti-fusing agent include, for example, adding it through an inlet for adding raw materials into the rotary kiln together with the raw material to be treated, or blowing it through a burner that heats the rotary kiln.

[0012] However, since the ring-shaped deposits are formed midway along the length of the rotary kiln, when the anti-fusing agent is added from the inlet or burner side, it takes a long time for the anti-fusing agent to reach the area where the ring-shaped deposits have formed, which causes a problem that the ring-shaped deposits grow sufficiently before the anti-fusing agent reaches the area where the ring-shaped deposits have formed, and therefore the effect of reducing the clogging of the rotary kiln cannot be sufficiently obtained.

[0013] Therefore, the method for reducing clogging in a rotary kiln of this embodiment has a scoop feeder between both longitudinal ends of the rotary kiln, and can include an anti-fusing agent addition process in which an anti-fusing agent is introduced into the rotary kiln via the scoop feeder.

[0014] According to the method for reducing clogging of a rotary kiln of this embodiment, the anti-fusing agent can be fed into the rotary kiln through a scoop feeder installed in the middle of the rotary kiln. Therefore, even if the anti-fusing agent is added at a stage where the formation of a ring-shaped deposit is recognized, the anti-fusing agent can be supplied to the part where the ring-shaped deposit is formed in a short time. As a result, the growth of the ring-shaped deposit can be suppressed, and the clogging of the rotary kiln can be effectively suppressed.

[0015] The configuration of a heat treatment device to which the method for reducing clogging in a rotary kiln of this embodiment can be suitably applied will be described, and then the anti-fusing agent addition step of this embodiment will be described. (1) Heat treatment equipment An example of the configuration of a heat treatment device including a rotary kiln, which can suitably carry out the method for reducing clogging in a rotary kiln according to this embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of a heat treatment device 10, and Figure 2 is a cross-sectional view taken along line AA' in Figure 1. (1-1) About rotary kilns The heat treatment device 10 shown in FIG. 1 has a rotary kiln 100. A body part 101, which is a furnace body of the rotary kiln 100, has a substantially cylindrical shape, and the body part 101 is configured to be rotatable around a central axis CA as a rotation axis. The rotary kiln 100 is provided with an inclination downward from an inlet end 102, which is one end in the longitudinal direction, to a discharge end 103, which is the other end in the longitudinal direction. Therefore, the material to be treated, which is a raw material introduced from the inlet end 102 side, moves inside the rotating body part 101 to the discharge end side. As described later, a burner 104 is provided on the discharge end 103 side, and the combustion heat of the fossil fuel burned by the burner 104 moves in the opposite direction to the movement direction of the material to be treated, that is, from the discharge end 103 side to the inlet end 102 side, thereby countercurrent heating the material to be treated.

[0016] The rotary kiln 100 has an introduction port 1021 at an introduction end 102 which is one end in the longitudinal direction, and the material to be treated can be introduced into the body portion 101 from the introduction port 1021 .

[0017] A discharge chute, which is a discharge port 1031, is provided at the other longitudinal end of the rotary kiln 100, and can be configured to discharge the workpieces that have completed the heat treatment inside the body 101. The workpieces that have completed the heat treatment can be transported to an apparatus such as an electric furnace for other processing as necessary. In addition, a burner 104 is provided at the discharge end 103, which can burn fossil fuels such as heavy oil to heat the workpieces and the like that have been placed inside the body 101 of the rotary kiln 100. (1-2) Scoop feeder The heat treatment device 10 may have a scoop feeder midway through the rotary kiln 100, i.e., between the inlet end 102 and the outlet end 103. Figure 2 shows a cross section at the position where the scoop feeder is provided, i.e., a cross section taken along line AA'.

[0018] As shown in Fig. 2, the rotary kiln 100 can have a rotating body 101 and an outer shell 110 that covers the body 101. Note that the outer shell 110 does not need to be provided so as to cover the entire surface of the body 101, and can be provided only where necessary, such as where a scoop feeder is provided, as shown in Fig. 1.

[0019] The object 21 to be treated is introduced into the body portion 101 through an inlet 1021, and can move toward the discharge end 103 as the body portion 101 rotates.

[0020] A space 120 is formed between the body 101 and the outer shell 110, and an anti-fusing agent can be supplied to the space 120 via an additive supply port 111 provided in the outer shell 110. The additive supply port 111 can be connected to additive supply means 221 for supplying various additives as required.

[0021] The additive supplying means 221 may be a melting inhibitor supplying means for supplying a melting inhibitor.

[0022] In addition, the heat treatment device 10 can also perform, for example, a reduction process. For this reason, the additive supplying means 221 can further include a reducing agent supplying means. Also, the additive supplying means 221 may be a single additive supplying means that supplies an additive in which, for example, an anti-fusing agent and a reducing agent are mixed in advance.

[0023] The configuration of the additive supplying means 221 is not particularly limited, and may be configured so that the opening of the opening provided on the additive supply port 111 side can be adjusted according to the supply amount of the additive, so that the supply amount of the additive that falls freely through the opening can be adjusted. Also, the additive supplying means 221 may be configured to have a conveying means such as a screw conveyor, and the conveying speed of the additive by the conveying means can be adjusted, so that the supply amount of the additive can be adjusted by the conveying speed.

[0024] The scoop feeder 130 can be formed, for example, of an L-shaped pipe bent between a tip portion 131 and a straight portion 132. The scoop feeder 130 can rotate together with the body portion 101, for example, in a clockwise direction (right direction) as shown by the arrow in FIG. 2. During such rotation, the tip portion 131 can scoop up the additive 22 supplied to the space portion 120, and the scooped additive 22 can be passed through the straight portion 132 and fed into the body portion 101.

[0025] In the rotary kiln 100, the location where the scoop feeder is provided is not particularly limited, and the scoop feeder can be provided at any location depending on the temperature distribution inside the body portion 101 of the rotary kiln 100, etc.

[0026] For example, a scoop feeder can be provided in a location where ring-shaped deposits are likely to form, for example, a location where the temperature inside the body 101 is close to the melting point of the workpiece. By providing a scoop feeder in a location where the body 101 is in the above-mentioned temperature range, for example, and supplying the anti-fusing agent, the anti-fusing agent can be supplied to the area where ring-shaped deposits are likely to form in a particularly short time.

[0027] As described above, the location where the scoop feeder is provided is not particularly limited. For example, the distance L110 from the discharge end 103 to the end of the outer shell 110 on the side of the introduction end 102 where the scoop feeder is provided is preferably 5% to 95% of the length L101 of the body 101 of the rotary kiln 100 in the longitudinal direction, more preferably 10% to 90%. (2) Operating conditions of rotary kilns The operating conditions of the rotary kiln are not particularly limited and can be selected as desired depending on the type of material to be treated, the treatment to be carried out, and the like.

[0028] As described above, the heat treatment device 10 can also perform reduction treatment and the like.

[0029] The rotation speed of the rotary kiln 100, i.e., the rotation speed of the body portion 101 that constitutes the rotary kiln 100, is not particularly limited, but is preferably, for example, about 0.5 rpm or more and 1.5 rpm or less.

[0030] By setting the rotation speed of the rotary kiln 100 to 0.5 rpm or more, the stirring force within the rotary kiln 100 can be sufficiently increased, allowing the reaction to proceed sufficiently while exposing additives, etc. that were added during the reaction, and also reducing deformation due to its own weight when the kiln body becomes soft due to high temperatures.

[0031] Furthermore, by setting the rotation speed of the rotary kiln to 1.5 rpm or less, the materials to be treated introduced into the rotary kiln 100 can remain in the rotary kiln 100 for a sufficient period of time, thereby ensuring the desired heat treatment time. (3) Anti-fusing agent addition process In the anti-adhesive agent addition step, the anti-adhesive agent can be introduced into the rotary kiln, specifically into the body portion where the heat treatment of the material to be treated is being carried out, via the scoop feeder already described.

[0032] The anti-fusing agent addition process can be performed at any timing, for example, when the formation of a ring-shaped deposit on the body portion 101 of the rotary kiln 100 is detected, or when the formation of a ring-shaped deposit can be predicted or estimated based on information such as the composition of the raw material ore added and the temperature of the outer wall of the furnace.

[0033] The method for detecting the formation of ring-shaped deposits is not particularly limited, but can be detected, for example, by changes in the amount of treated material discharged from the rotary kiln 100, images directly monitored from the inside of the body portion 101, temperature information outside the furnace, etc. (3-1) Anti-fusing agents The anti-fusing agent may be any material capable of suppressing the growth of ring-shaped deposits, and for example, a ceramic material having a high melting point can be suitably used. By using a ceramic material having a high melting point as an anti-fusing agent, for example, the workpiece in a molten state can be coated, and the workpiece can be prevented from adhering to the inner wall of the furnace and growing into a ring-shaped deposit.

[0034] The anti-fusing agent can be selected according to the material to be treated so as not to adversely affect the components of the material to be treated, and is not particularly limited. It is preferable that the anti-fusing agent contains one or more types selected from, for example, silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide. (3-2) Other additives As described above, the heat treatment device 10 can also perform, for example, reduction treatment. Specifically, for example, a reducing agent can be added from a scoop feeder, and the material to be treated and the reducing agent can be mixed and heated in the rotary kiln. At this time, the material to be treated can be reduced, and in some cases, dried. For example, coal can be suitably used as the reducing agent. For this reason, when performing the anti-fusing agent addition step, coal can be added in addition to the anti-fusing agent into the rotary kiln, specifically into the body portion, via the scoop feeder.

[0035] In addition, when performing reduction treatment of the workpiece, since it is necessary to continuously add a reducing agent during the reduction treatment, a reducing agent addition step can be performed separately from the anti-fusing agent addition step. Then, when it is detected that a ring-shaped deposit has formed, the reducing agent addition step and the anti-fusing agent addition step are performed simultaneously.

[0036] Since coal ash can also function as a fusion inhibitor, when adding coal, coal containing coal ash can be preferably used, and in particular, coal with a high coal ash content can be more preferably used.

[0037] In addition, when performing the anti-fusing agent addition process, in order to adjust the temperature inside the body portion 101 of the rotary kiln 100, a gas such as air can also be supplied into the rotary kiln, specifically into the body portion.

[0038] Usually, when reduction treatment is performed, air is not supplied in order to maintain the atmosphere in the body 101 of the rotary kiln 100 as a reducing atmosphere. However, even when reduction treatment is performed, air can also be supplied as described above in order to supply the anti-adhesive agent to an appropriate temperature range. When reduction treatment of the material to be treated is performed in a rotary kiln and air is supplied as described above, the anti-adhesive agent, coal, and air are supplied into the rotary kiln, specifically into the body, via a scoop feeder when the anti-adhesive agent addition step is performed. (4) About the object to be treated The material to be treated in the method for reducing clogging in a rotary kiln according to the present embodiment is not particularly limited, and examples thereof include ores containing various metal components and ceramic raw materials.

[0039] In particular, the material to be treated may be various ores. In particular, metal ores that are required to be refined generally contain a lot of moisture and are oxidized. According to the method for reducing clogging of a rotary kiln of this embodiment, drying and reduction can be efficiently performed while reducing clogging of the rotary kiln, so it is preferable that the material to be treated includes metal ores. Note that the material to be reduced may be composed of metal ores.

[0040] The metal contained in the metal ore is not particularly limited, but is preferably a metal containing a non-ferrous metal, and more preferably an ore containing one or more metals selected from nickel, zinc, etc.

[0041] The object to be treated may be pre-dried in advance to reduce or remove some of the adhering moisture. [Heat treatment equipment] The heat treatment device of this embodiment can have a rotary kiln, a scoop feeder arranged between both longitudinal ends of the rotary kiln, and an anti-fusing agent supplying means provided in the scoop feeder for supplying an anti-fusing agent.

[0042] According to the heat treatment device of this embodiment, the above-mentioned method for reducing clogging in a rotary kiln can be implemented, and therefore, the description of the matters already described will be omitted.

[0043] The heat treatment apparatus of this embodiment can have a rotary kiln, a scoop feeder, and an additive supplying means, as described with reference to FIGS.

[0044] The rotary kiln and the scoop feeder have already been explained, so a detailed explanation will be omitted here.

[0045] The additive supplying means 221 may be, for example, a fusion inhibitor supplying means for supplying a fusion inhibitor. The fusion inhibitor may be any material capable of suppressing the growth of ring-shaped deposits, and for example, a ceramic material having a high melting point may be suitably used. By using a ceramic material having a high melting point as the fusion inhibitor, for example, the workpiece in a molten state can be coated, and the workpiece can be prevented from adhering to the inner wall of the furnace and growing into a ring-shaped deposit.

[0046] The anti-fusing agent can be selected depending on the object to be treated so as not to adversely affect the components of the object to be treated. There is no particular limitation on the anti-fusing agent, but it is preferable that the anti-fusing agent contains one or more types selected from, for example, silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide.

[0047] As described above, the heat treatment device of this embodiment can also perform reduction treatment of the object to be treated as necessary, and in this case, coal, which is a reducing agent, can be supplied from the scoop feeder. For this reason, the additive supplying means 221 can also have a coal supplying means (reducing agent supplying means) that supplies coal, which is a reducing agent, in addition to the anti-fusing agent supplying means. That is, the heat treatment device of this embodiment can also have a coal supplying means that supplies coal provided in the scoop feeder. Note that the coal and the anti-fusing agent can also be supplied in a state of a premixed mixture, and in this case, the anti-fusing agent supplying means and the coal supplying means can be configured as a single device rather than as separate devices.

[0048] The additive supplying means 221 is not particularly limited in detail as long as it is configured to be able to supply the anti-adhesion agent as described above and, if necessary, coal as a reducing agent.

[0049] The configuration of the additive supplying means 221 is not particularly limited, and may include, for example, a storage container and a supply amount adjusting means.

[0050] The supply amount adjusting means may be configured to adjust the opening of an opening provided on the additive supply port 111 side of the storage container in accordance with the supply amount of the additive, so that the supply amount of the additive that falls freely through the opening can be adjusted. The supply amount adjusting means may also be configured to have a conveying means such as a screw conveyor, and to adjust the conveying speed of the additive by the conveying means, so that the supply amount of the additive can be adjusted by the conveying speed.

[0051] In addition, FIG. 1 shows an example in which the additive supply means 221 is provided in the additive supply port 111, but is not limited to this form. For example, the additive supply means 221 and the additive supply port 111 may be connected by a pipe, and the two components may be separated from each other.

[0052] As described above, when the anti-fusing agent is supplied, a gas such as air can also be supplied to adjust the temperature inside the body 101 of the rotary kiln 100. For this reason, the heat treatment device 10 of this embodiment can also have an air supplying means provided in the scoop feeder for supplying air.

[0053] The configuration of the air supply means is not particularly limited, but may include, for example, a blower or an air cylinder, and may include a regulator or valve to control the flow rate or air supply as necessary.

[0054] According to the heat treatment device of the present embodiment described above, the scoop feeder arranged between both longitudinal ends of the rotary kiln is provided with a means for supplying an anti-fusing agent, so that the anti-fusing agent can be supplied at an appropriate timing, which suppresses the growth of ring-shaped deposits and reduces clogging of the rotary kiln. [Explanation of symbols]

[0055] 10 Heat treatment device 100 Rotary Kiln 130 Scoop Feeder

Claims

1. The rotary kiln has a scoop feeder between both ends in the longitudinal direction thereof, and the method includes a fusion inhibitor adding step of feeding an fusion inhibitor into the rotary kiln through the scoop feeder, The method for reducing clogging in a rotary kiln, wherein the anti-fusing agent contains one or more selected from the group consisting of silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide.

2. The method for reducing blockage in a rotary kiln according to claim 1, wherein coal is also fed into the rotary kiln through the scoop feeder when the anti-fusing agent addition step is performed.

3. The method for reducing blockage in a rotary kiln according to claim 1 or 2, wherein air is also supplied into the rotary kiln in the anti-fusing agent addition step.

4. Rotary kiln and A scoop feeder disposed between both longitudinal ends of the rotary kiln; and a melting inhibitor supplying means provided in the scoop feeder for supplying a melting inhibitor. The heat treatment device, wherein the anti-fusing agent contains at least one selected from the group consisting of silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide.

5. 5. The heat treatment apparatus according to claim 4, further comprising a coal supplying means provided in said scoop feeder for supplying coal.

6. 6. The heat treatment apparatus according to claim 4, further comprising air supply means provided in said scoop feeder for supplying air.

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