JP2022171459A - Blockage reduction method of rotary kiln and heat treating device - Google Patents

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

The present invention relates to a clogging reduction method for a rotary kiln and a heat treatment apparatus.

BACKGROUND ART A rotary kiln is used for drying and reduction treatment of ores, and for producing various ceramic materials such as cement (see Patent Document 1, for example).

JP 2014-141719 A

A rotary kiln has a substantially cylindrical shape, and a material to be processed, which is a raw material, is generally charged from one end side and heated from the other end side by a heating means such as a burner. The rotary kiln is arranged so that the other end side is lower, and by rotating about the central axis, the material to be processed that has been put in is heated while gradually moving toward the other end side. Then, the product obtained after the heat treatment is discharged from the discharge port provided on the other end side.

By the way, when the rotary kiln is operated, when the temperature of the high-temperature region formed inside the rotary kiln by the heating means becomes close to the melting point of the substance in the material to be processed, the material to be processed adheres to the inner wall of the rotary kiln, forming a ring-shaped attachment. A kimono may be formed. When such ring-shaped deposits are formed, the material to be processed in the rotary kiln becomes difficult to flow, and the ring-shaped deposits grow to eventually clog the rotary kiln, making it impossible to operate in some cases.

Therefore, in view of the above-described problems of the prior art, it is an object of one aspect of the present invention to provide a clogging reduction method for a rotary kiln that can reduce clogging of the rotary kiln.

In order to solve the above problems, according to one aspect of the present invention,
Provided is a method for reducing clogging of a rotary kiln, which has a scoop feeder between both ends in the longitudinal direction of the rotary kiln, and has an anti-fusing agent addition step of charging an anti-fusing agent into the rotary kiln via the scoop feeder. .

According to one aspect of the present invention, it is possible to provide a clogging reduction method for a rotary kiln that can reduce clogging of a rotary kiln.

FIG. 1 is a schematic diagram of a heat treatment apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA' of FIG.

Hereinafter, the embodiments for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments, and without departing from the scope of the present invention, the following embodiments Various modifications and substitutions can be made.
[Clogging reduction method of rotary kiln]
As a method for suppressing the growth of the ring-shaped deposits and preventing clogging of the rotary kiln, it is possible to add an anti-fusing agent at the stage when the formation of the ring-shaped deposits is recognized.

As a method of adding the anti-fusing agent, for example, a method of charging the raw material into the furnace of the rotary kiln together with the material to be treated, or a method of blowing the agent from a burner that heats the rotary kiln are conceivable.

However, since the ring-shaped deposits are formed in the middle of the longitudinal direction of the rotary kiln, when the anti-fusing agent is introduced from the input port or the burner side, the ring-shaped deposits are not fused to the part where the ring-shaped deposits are formed. It takes a lot of time for the inhibitor to arrive. For this reason, the ring-shaped deposits grow sufficiently before the anti-fusing agent reaches the portion where the ring-shaped deposits are formed, and the effect of reducing clogging of the rotary kiln cannot be sufficiently obtained. There is a problem.

Therefore, in the clogging reduction method for a rotary kiln of the present embodiment, a scoop feeder is provided between both ends in the longitudinal direction of the rotary kiln, and the anti-fusing agent is added into the rotary kiln via the scoop feeder. can have a process.

According to the clogging reduction method for a rotary kiln of the present embodiment, the anti-fusing agent can be introduced into the rotary kiln through the scoop feeder provided in the middle of the rotary kiln. Therefore, for example, even if the anti-fusion agent is added at the stage when the formation of a ring-shaped deposit is recognized, the anti-fusion agent can be supplied in a short time to the portion where the ring-shaped deposit is formed. . As a result, it is possible to suppress the growth of ring-shaped deposits and effectively suppress the clogging of the rotary kiln.

After describing the configuration of a heat treatment apparatus to which the method for reducing clogging of a rotary kiln of the present embodiment is preferably applied, the anti-fusing agent addition step of the present embodiment will be described.
(1) Heat Treatment Apparatus A configuration example of a heat treatment apparatus including a rotary kiln that can suitably implement the method for reducing clogging of a rotary kiln according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a perspective view of the heat treatment apparatus 10, and FIG. 2 is a cross-sectional view taken along line AA' of FIG.
(1-1) Rotary Kiln The heat treatment apparatus 10 shown in FIG. 1 has a rotary kiln 100 . A body portion 101 serving as a furnace body of the rotary kiln 100 has a substantially cylindrical shape, and the body portion 101 is configured to be rotatable about a central axis CA as a rotation axis. The rotary kiln 100 is inclined downward from an introduction end 102, which is one end in the longitudinal direction, toward a discharge end 103, which is the other end in the longitudinal direction. Therefore, the material to be processed that is introduced from the introduction end 102 side moves to the discharge end side inside the rotating body portion 101 . As will be 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 is directed in the direction opposite to the moving direction of the material to be treated, that is, from the discharge end 103 side. By moving to the introduction end 102 side, the object to be processed is heated in counterflow.

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

A discharge end 103, which is the other end in the longitudinal direction of the rotary kiln 100, is provided with a discharge chute, which is a discharge port 1031, so that the material to be processed that has undergone heat treatment inside the body part 101 can be discharged. can be configured to After the heat treatment, the object to be treated can be transported to an electric furnace or other apparatus for other treatment as required. Also, a burner 104 is provided at the discharge end 103 to burn fossil fuel such as heavy oil, thereby heating the material to be processed and the like introduced into the body 101 of the rotary kiln 100 .
(1-2) Scoop Feeder The heat treatment apparatus 10 can have a scoop feeder in the middle of the rotary kiln 100 , ie, between the introduction end 102 and the discharge end 103 . FIG. 2 shows a cross section at the position where the scoop feeder is provided, that is, a cross sectional view along line AA'.

As shown in FIG. 2, the rotary kiln 100 can have a rotating body 101 and an outer shell 110 covering the body 101 . It should be noted that the outer shell 110 does not have to be provided so as to cover the entire surface of the body 101. For example, as shown in FIG.

An object to be processed 21 introduced from an inlet 1021 is introduced into the body portion 101 and can move toward the discharge end 103 side as the body portion 101 rotates.

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

The additive supply means 221 can be an anti-fusing agent supply means for supplying an anti-fusing agent.

Note that the heat treatment apparatus 10 can also perform, for example, a reduction treatment. For this reason, the additive supply means 221 can also have a reducing agent supply means. Further, the additive supply unit 221 may be one additive supply unit that supplies an additive obtained by pre-mixing, for example, an anti-fusion agent and a reducing agent.

The configuration of the additive supply means 221 is not particularly limited. It may be possible to adjust the supply amount of the dropping additive. In addition, for example, it may have a conveying means such as a screw conveyor, the conveying speed of the additive by the conveying means may be adjusted, and the feeding amount of the additive may be adjusted by the conveying speed.

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

In the rotary kiln 100 , the location where the scoop feeder is provided is not particularly limited, and it can be provided at any location according to the temperature distribution inside the body portion 101 of the rotary kiln 100 .

For example, a scoop feeder can be provided at a location where ring-shaped deposits are likely to be formed, for example, at a location where the temperature inside the body portion 101 is near the melting point of the object to be processed. By providing a scoop feeder in a place where the body portion 101 is in the above temperature range, for example, and supplying the anti-fusion agent, the anti-fusion agent can be supplied particularly in a short time to the region where ring-shaped deposits are likely to be formed. is.

The location where the scoop feeder is provided is not particularly limited as described above. For example, the distance L110 from the discharge end 103 to the end of the outer shell 110 provided with the scoop feeder on the introduction end 102 side is preferably 5% or more and 95% or less of the longitudinal length L101 of the body portion 101 of the rotary kiln 100. 10% or more and 90% or less is more preferable.
(2) Operating Conditions of Rotary Kiln Operating conditions of the rotary kiln are not particularly limited, and can be arbitrarily selected according to the type of material to be treated, the treatment to be performed, and the like.

As described above, the heat treatment apparatus 10 can also perform reduction treatment and the like.

The number of revolutions of the rotary kiln 100, that is, the number of revolutions of the body portion 101 constituting the rotary kiln 100 is also not particularly limited, but is preferably about 0.5 rpm or more and 1.5 rpm or less, for example.

By setting the rotation speed of the rotary kiln 100 to 0.5 rpm or more, the stirring power in the rotary kiln 100 can be sufficiently increased, and the reaction can be sufficiently progressed while exposing the additives etc. introduced in the middle. Self-weight deformation when the kiln main body is softened can be reduced.

In addition, by setting the rotational speed of the rotary kiln to 1.5 rpm or less, the material to be processed and the like introduced into the rotary kiln 100 can remain in the rotary kiln 100 for a sufficient time, and the desired heat treatment time can be secured.
(3) Anti-fusing agent addition step In the anti-fusing agent addition step, the anti-fusing agent is fed into the rotary kiln through the scoop feeder described above, specifically into the body portion where the workpiece is being heat-treated. can.

The anti-fusing agent addition step can be performed at any time. It can be carried out when the formation of ring-shaped deposits is predicted or can be predicted based on information such as the outer wall temperature.

The method for detecting the formation of ring-shaped deposits is not particularly limited, but for example, changes in the amount of processed material discharged from the rotary kiln 100, an image directly monitoring the inside of the body portion 101, and the outside of the furnace can be detected by temperature information, etc.
(3-1) Anti-Fusing Agent Any material can be used as the anti-fusing agent as long as it can suppress the growth of ring-shaped deposits. For example, a ceramic material with a high melting point can be suitably used. By using a ceramic material with a high melting point as an anti-adhesion agent, it is possible to coat the object to be processed in a molten state, for example, to prevent the object from adhering to the inner wall of the furnace and to prevent ring-shaped deposits from growing.

The anti-fusing agent can be selected according to the object to be treated so as not to adversely affect the components of the object to be treated, and is not particularly limited. It is preferable to include more than one type.
(3-2) Other Additives As described above, the heat treatment apparatus 10 can also perform, for example, reduction treatment. Specifically, for example, a reducing agent can be added from a scoop feeder, and the object to be treated and the reducing agent can be heated while being mixed in a rotary kiln. At this time, the object to be treated can be reduced and, in some cases, dried. Coal, for example, can be suitably used as the reducing agent. Therefore, when performing the anti-fusing agent addition step, coal may be fed in addition to the anti-fusing agent into the rotary kiln, specifically, into the body portion via the scoop feeder.

In the case where the object to be treated is reduced, it is necessary to continuously add the reducing agent while the reduction treatment is being performed. . Then, when it is detected that a ring-shaped deposit is formed, the reducing agent addition step and the anti-fusing agent addition step are performed simultaneously.

Since coal ash can also function as an anti-fusing agent, when adding coal, coal containing coal ash can be preferably used, and coal with a high content of coal ash can be more preferably used.

Further, in order to adjust the temperature in the body portion 101 of the rotary kiln 100 when performing the anti-fusing agent addition step, a gas such as air can also be supplied to the rotary kiln, specifically, the body portion. .

Normally, when the reducing treatment is performed, air is not supplied in order to keep the atmosphere in the body portion 101 of the rotary kiln 100 in a reducing atmosphere. However, even when the reduction treatment is performed, air can also be supplied as described above for the purpose of supplying the anti-fusing agent to an appropriate temperature range. In addition, when performing the reduction treatment of the material to be treated in the rotary kiln and supplying air as described above, when performing the anti-fusing agent addition step, the inside of the rotary kiln, specifically, the body part, through the scoop feeder An anti-fusing agent, coal, and air will be supplied.
(4) Object to be processed The object to be processed to be subjected to the method for reducing clogging of 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.

In particular, various ores can be mentioned as the object to be treated. In particular, metal ores that require refining generally contain a lot of water and are oxidized. According to the method for reducing clogging of a rotary kiln of the present embodiment, drying and reduction can be performed efficiently while clogging of the rotary kiln is reduced. preferable. Note that the material to be reduced may be composed of metal ore.

The metal contained in the metal ore is not particularly limited, but for example, it is preferably a metal containing a non-ferrous metal, and more preferably an ore containing one or more metals selected from nickel, zinc, and the like.

Incidentally, it is also possible to pre-dry the object to be treated in advance to reduce or remove a part of the adhering moisture.
[Heat treatment equipment]
The heat treatment apparatus of this embodiment includes a rotary kiln, a scoop feeder disposed between both ends in the longitudinal direction of the rotary kiln, and an anti-fusing agent supply means provided on the scoop feeder for supplying an anti-fusing agent. be able to.

According to the heat treatment apparatus of this embodiment, the clogging reduction method of the rotary kiln described above can be carried out. Therefore, the description of the matters that have already been described will be omitted.

The heat treatment apparatus of this embodiment can have a rotary kiln, a scoop feeder, and an additive supply means, as described with reference to FIGS. 1 and 2 .

Since the rotary kiln and the scoop feeder have already been explained, the explanation is omitted here.

The additive supply means 221 can also be an anti-fusing agent supply means for supplying an anti-fusing agent, for example. The anti-fusion agent may be any material as long as it can suppress the growth of ring-shaped deposits, and for example, a ceramic material with a high melting point can be suitably used. By using a ceramic material with a high melting point as an anti-adhesion agent, it is possible to coat the object to be processed in a molten state, for example, to prevent the object from adhering to the inner wall of the furnace and to prevent ring-shaped deposits from growing.

The anti-fusing agent can be selected according to the object to be treated so as not to adversely affect the components of the object to be treated, and is not particularly limited. For example, one or more selected from silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide. is preferably included.

Further, as described above, the heat treatment apparatus of the present embodiment can also perform a reduction treatment of the object to be treated as necessary, and in this case, coal as a reducing agent can be supplied from the scoop feeder. Therefore, the additive supply means 221 can have coal supply means (reducing agent supply means) for supplying coal as a reducing agent in addition to the anti-fusing agent supply means. That is, the heat treatment apparatus of this embodiment can also have a coal supply means for supplying coal provided in the scoop feeder. The coal and the anti-fusing agent can also be supplied in a state of a mixture that has been mixed in advance. It can also be configured by

The additive supply means 221 is not particularly limited as long as it is configured to supply the anti-fusing agent and, if necessary, coal as a reducing agent as described above.

The configuration of the additive supply means 221 is not particularly limited, and can have, for example, a storage container and a supply amount adjustment means.

For example, the supply amount adjusting means is configured to be able to adjust the degree of opening of an opening provided on the additive supply port 111 side of the storage container according to the supply amount of the additive, and the additive freely falls through the opening. You may enable it to adjust the supply amount of an additive. Further, the supply amount adjusting means has a conveying means such as a screw conveyor, for example, and is configured so that the conveying speed of the additive by the conveying means can be adjusted, and the feed amount of the additive can be adjusted by the conveying speed. good too.

Note that 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 such a form. Both members may be separated by connecting with piping.

Further, as described above, when the anti-fusion agent is supplied, gas such as air can also be supplied together in order to adjust the temperature inside the body portion 101 of the rotary kiln 100 . For this reason, the heat treatment apparatus 10 of the present embodiment can also have air supply means for supplying air provided in the scoop feeder.

Although the configuration of the air supply means is not particularly limited, it can have, for example, a blower, an air cylinder, etc., and can have a regulator and a valve so as to control the flow rate and air supply as necessary.

According to the heat treatment apparatus of this embodiment described above, the scoop feeder disposed between the longitudinal ends of the rotary kiln is provided with the anti-fusing agent supply means so that the anti-fusing agent can be supplied. there is Therefore, the anti-fusing agent can be supplied at an appropriate timing, the growth of ring-shaped deposits can be suppressed, and clogging of the rotary kiln can be reduced.

10 heat treatment equipment 100 rotary kiln 130 scoop feeder

Claims (8)

A rotary kiln clogging reduction method comprising a scoop feeder between both ends of a rotary kiln in the longitudinal direction, and an anti-fusing agent addition step of feeding an anti-fusing agent into the rotary kiln via the scoop feeder. 2. The method of reducing clogging in a rotary kiln according to claim 1, wherein the anti-fusing agent contains one or more selected from silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide. 3. The method for reducing clogging of a rotary kiln according to claim 1, wherein coal is also fed into the rotary kiln through the scoop feeder when performing the anti-fusing agent addition step. 4. The method for reducing clogging of a rotary kiln according to claim 1, wherein air is also supplied into the rotary kiln in the step of adding anti-fusing agent. rotary kiln and
a scoop feeder disposed between longitudinal ends of the rotary kiln;
and anti-fusing agent supply means for supplying an anti-fusing agent provided in the scoop feeder. 6. The heat treatment apparatus according to claim 5, wherein the anti-fusing agent contains one or more selected from silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide. 7. The heat treatment apparatus according to claim 5, further comprising coal supply means for supplying coal provided in said scoop feeder. 8. The heat treatment apparatus according to any one of claims 5 to 7, further comprising air supply means for supplying air provided in said scoop feeder.

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