JP2023000051A - Reduction treatment method and reduction treatment apparatus - Google Patents

Abstract

To provide a reduction treatment method by which it is possible to decrease a concentration of a sulfur component in exhaust gas.SOLUTION: A reduction treatment method is intended to carry out reduction treatment of a material subjected to reduction by a rotary kiln. A scoop feeder is disposed in a midway of the rotary kiln. The method includes a reaction treatment agent addition step of loading a reductant and a desulfurization agent through the scoop feeder. The reductant is coal, and the desulfurization agent is quicklime.SELECTED DRAWING: Figure 1

Description

The present invention relates to a reduction treatment method and a reduction treatment apparatus.

For example, ores are usually oxidized and contain a large amount of water, and thus the ores are conventionally subjected to drying and reduction treatment before being melted in an electric furnace or the like (see, for example, Patent Document 1). .

JP 2014-141719 A

A carbon component, such as coal, is used as a reducing agent when reducing ores and other materials to be reduced. Exhaust gas containing Although it is conceivable to use an oxidation catalyst to purify such exhaust gas, the exhaust gas usually contains a sulfur component due to raw materials such as ores. Therefore, when the exhaust gas containing sulfur components is brought into contact with the oxidation catalyst, there is a problem such as deterioration of the performance of the oxidation catalyst.

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 reduction treatment method capable of reducing the concentration of sulfur components in exhaust gas.

In order to solve the above problems, according to one aspect of the present invention,
A reduction treatment method for reducing a reducible material in a rotary kiln,
A scoop feeder is provided in the middle of the rotary kiln, and a reaction treatment agent addition step of charging a reducing agent and a desulfurizing agent through the scoop feeder,
The reducing agent is coal, and the desulfurizing agent is quicklime.

According to one aspect of the present invention, it is possible to provide a reduction treatment method capable of reducing the concentration of sulfur components in exhaust gas.

FIG. 1 is a schematic diagram of a reduction 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.
[Method of reduction treatment]
The reduction treatment method of the present embodiment is a reduction treatment method in which a material to be reduced is reduced in a rotary kiln, and is a reaction treatment in which a scoop feeder is provided in the middle of the rotary kiln and a reducing agent and a desulfurizing agent are fed through the scoop feeder. It can have an agent addition step.

The reducing agent can be coal, and the desulfurizing agent can be quicklime.
(1) Reducible substance Although the reducible substance to be subjected to the reduction treatment method of the present embodiment is not particularly limited, the concentration of sulfur components in the exhaust gas can be reduced according to the reduction treatment method of the present embodiment. It is preferably a reducible material containing a sulfur component.

Various ores can be mentioned as the material to be reduced. In particular, metal ores that require refining generally contain a lot of water and are oxidized. Further, according to the reduction treatment method of the present embodiment, since drying and reduction can be efficiently performed, it is preferable that the material to be reduced includes metal ore. 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 preliminarily dry the object to be reducible so as to reduce or remove a part of the adhering moisture.
(2) Reaction treatment agent addition step The reduction treatment method of the present embodiment can have a reaction treatment agent addition step as described above.

In the reaction processing agent addition step, a scoop feeder is provided in the middle of the rotary kiln, and the reducing agent and the desulfurization agent can be fed through the scoop feeder. In the reaction treating agent addition step, the reducing agent and the desulfurizing agent can be charged and added to the reducible material heated in the rotary kiln as described above.

Since the reducing agent and the desulfurizing agent can be added at different timings, the reaction treatment agent supply step may include a reducing agent supply step for supplying the reducing agent and a desulfurizing agent supply step for supplying the desulfurizing agent. can.

In the reduction treatment method of the present embodiment, after the step of adding the reaction treatment agent, the material to be reduced, the reducing agent, and the desulfurizing agent can be mixed and heated in the rotary kiln. At this time, the reduction treatment method of the present embodiment can perform a reduction drying step of reducing and drying the reducible material. Further, the reduction treatment method of the present embodiment can carry out a desulfurization step of reducing or removing sulfur components contained in the exhaust gas generated from the material to be reduced or the like during the reduction drying step using a desulfurizing agent.

An example of the configuration of the rotary kiln and the reaction treatment agent that can be used in the reduction treatment method of the present embodiment will be described below.
(2-1) Rotary Kiln A configuration example of a rotary kiln that can suitably carry out the reduction treatment method of the present embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a perspective view of a rotary kiln, and FIG. 2 is a cross-sectional view taken along line AA' of FIG.

A body portion 100 of the rotary kiln 10 shown in FIG. 1 has a substantially cylindrical shape, and the body portion 100 is configured to be rotatable about a central axis CA as a rotation axis. The rotary kiln 10 is inclined downward from an introduction end 101, which is one end in the longitudinal direction, toward a discharge end 102, which is the other end in the longitudinal direction. Therefore, the reducible material introduced from the introduction end 101 side moves to the discharge end side inside the rotating body portion 100 . As will be described later, the burner 14 is provided on the discharge end 102 side, and the combustion heat of the fossil fuel burned by the burner is introduced from the discharge end 102 side in the opposite direction to the movement direction of the reducible material. By moving to the end 101 side, the reducible material is countercurrently heated.

The rotary kiln 10 has an inlet 11 at an introduction end 101 that is one end in the longitudinal direction, and the reducible material can be introduced into the body 100 from the inlet 11 . Since the reducible material has already been explained, the explanation is omitted here. Further, an exhaust pipe 12 is provided at the introduction end 101, through which the exhaust gas generated in the rotary kiln can be discharged. The exhaust pipe 12 is preferably connected to, for example, a catalyst tower 30, which will be described later, so as to reduce or remove carbon monoxide in the exhaust gas.

A discharge end 102, which is the other end in the longitudinal direction of the rotary kiln 10, is provided with a discharge chute, which is a discharge port 13, so that the reducible material that has undergone reduction processing inside the body part 100 can be discharged. can be configured as The reducible material that has been subjected to the reduction treatment can be transported to an electric furnace or the like for other treatment as required. Also, a burner 14 is provided at the discharge end 102 to burn fossil fuel such as heavy oil, thereby heating the reducible material introduced into the body 100 of the rotary kiln 10 .
(scoop feeder)
The rotary kiln 10 can have a scoop feeder in the middle, ie between the inlet end 101 and the discharge end 102 . 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 10 can have a rotating body 100 and a shell 110 covering the body 100 . 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 100. For example, as shown in FIG.

The reducible material 21 introduced from the inlet 11 is introduced into the body portion 100 and can move toward the discharge end 102 side as the body portion 100 rotates.

A space portion 120 is formed between the body portion 100 and the outer shell portion 110 , and a reducing agent and a desulfurizing agent are supplied to the space portion 120 through a reaction treating agent supply port 111 provided in the outer shell portion 110 . A reactive treatment agent 22 can be provided. A reaction treatment agent supply means 221 for supplying a reaction treatment agent can be connected to the reaction treatment agent supply port 111 as required.

The reaction treatment agent supply means 221 may have a reducing agent supply means for supplying a reducing agent and a desulfurization agent supply means for supplying a desulfurization agent. may be one reactive processing agent supply means for supplying the

The structure of the reactive processing agent supply means 221 is not particularly limited, and the opening provided on the side of the reactive processing agent supply port 111 can be adjusted in accordance with the supply amount of the reactive processing agent. It is also possible to adjust the amount of supply of the reactive treatment agent that freely falls through. Further, for example, a transport means such as a screw conveyor may be provided, the transport speed of the reactive treatment agent by the transport means may be adjusted, and the supply amount of the reactive treatment agent may be adjusted by the transport 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 100, for example, as indicated by the arrow in FIG. During such rotation, the reducing agent and desulfurizing agent supplied to the space portion 120 can be scooped up by the leading end portion 131 , and the scooped reducing agent and desulfurizing agent can pass through the straight portion 132 and be fed into the body portion 100 . .

In the rotary kiln 10 , 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 100 of the rotary kiln 10 .

For example, a scoop feeder can be provided at a place where the temperature inside the body portion 100 is 900° C. or higher and 1200° C. or lower from the viewpoint of sufficiently advancing the reduction reaction or the desulfurization reaction. By providing a scoop feeder at a place where the temperature inside the body portion 100 is 900° C. or more and 1200° C. or less and supplying the reaction treatment agent, fixed carbon in coal, which is a reducing agent contained in the reaction treatment agent, is fed. can be efficiently burned.

Note that the desulfurization reaction proceeds even at a temperature lower than that of the reduction reaction, for example, 100° C. or higher and 200° C. or lower. Therefore, scoop feeders can be provided at two locations along the longitudinal direction of the rotary kiln 10, for example. Specifically, a scoop feeder for adding the desulfurizing agent and a scoop feeder for adding the reducing agent can be provided.

The location where the scoop feeder is provided is not particularly limited as described above. For example, the distance L110 from the discharge end 102 to the end of the outer shell portion 110 provided with the scoop feeder on the introduction end 101 side is preferably 5% or more and 95% or less of the longitudinal length L100 of the body portion 100 of the rotary kiln 10. , more preferably 10% or more and 90% or less.
(Operating conditions of rotary kiln)
The operating conditions of the rotary kiln are not particularly limited, and can be arbitrarily selected according to the type of the reducible material.

For example, the temperature of the reducible material in the furnace at the discharge end 102 of the rotary kiln 10 can be 700° C. or more and 900° C. or less, and the exhaust gas temperature in the furnace at the introduction end 101 can be 250° C. or more and 400° C. or less.

By setting the temperature of the reducible material in the furnace at the discharge end 102 of the rotary kiln 10 to 700° C. or higher and the temperature of the exhaust gas in the furnace at the introduction end 101 to 250° C. or higher, the fixed carbon in coal, which is the supplied reducing agent, is reduced. Sufficient combustion can be achieved, and reduction treatment can be efficiently performed. In addition, by setting the temperature of the reducible material in the furnace at the discharge end 102 of the rotary kiln 10 to 900° C. or less and the temperature of the exhaust gas in the furnace at the introduction end 101 to 400° C. or less, the generation of lumps is suppressed, and the rotary kiln 10 It is possible to suppress the adhesion of crumbs to the furnace wall.

The number of rotations of the rotary kiln 10, that is, the number of rotations of the body portion 100 constituting the rotary kiln 10 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 10 to 0.5 rpm or more, the stirring power in the rotary kiln 10 is sufficiently increased, and the reaction can be sufficiently progressed while exposing the reaction processing agent such as the reducing agent introduced in the middle. .

In addition, by setting the rotation speed of the rotary kiln to 1.5 rpm or less, it is possible to prevent the reducible material introduced into the rotary kiln 10 from rising up in the rotary kiln 10 and being discharged from the introduction end 101 together with the exhaust gas as dust.
(2-2) Reaction treatment agent In the reaction treatment agent supply step, coal as a reducing agent and quicklime as a desulfurization agent can be supplied as reaction treatment agents.
(Regarding the reducing agent)
Coal can be suitably used as the reducing agent. In addition, the reducing agent may contain a reducing agent component other than coal, or may be composed only of coal.

It is preferable that the water content of the reducing agent is sufficiently removed. This is because, by removing water in the reducing agent, the time required for the water to evaporate after being supplied to the rotary kiln can be suppressed, and the fixed carbon contained in the reducing agent can be efficiently burned.
(About desulfurization agent)
It is believed that quicklime, which is a desulfurizing agent, reacts in the following formulas (1) to (3) to desulfurize. In the reduction treatment method of the present embodiment, since the material to be reduced is also dried, the atmosphere in the rotary kiln contains a sufficient amount of moisture, and the water in the formula (1) represents the atmosphere. supplied from

CaO+ _H2O →Ca(OH) ₂ (1)
SO2 ₊ Ca(OH) _2- > _CaSO3.1 /2H2O+1/ _2H2O ( ₂ )
CaSO3.1/2H2O+ ₁ / _{2O2 + 3} / _2H2O →CaSO4.2H2O ( ₃ )
The desulfurizing agent may contain calcium slaked Ca(OH) ₂ or the like in addition to quicklime, but it is preferably composed of only quicklime from the viewpoint of increasing the efficiency of drying the reducible material.

The reducing agent and the desulfurizing agent can be mixed in advance and supplied to the inside of the rotary kiln 10 as a reaction processing agent, but they may be supplied to the inside of the rotary kiln 10 without mixing the two.

The particle size of the reducing agent and desulfurizing agent is not particularly limited. When the reducing agent and the reaction treatment agent such as the reducing agent are mixed with the reducing agent by supplying it to the rotary kiln and rotating the rotary kiln, the reducing agent reacts in the reducing agent. It is preferable to adjust the particle size and the like so that the processing agent can be dispersed.

As described above, by adding a reducing agent and a reaction treatment agent, which is a desulfurizing agent, in the reaction treatment agent addition step, the reduction of the reducible material and the reduction of the sulfur component in the exhaust gas can be performed.
(3) Exhaust gas treatment process The reduction treatment method of the present embodiment can also have an exhaust gas treatment process in which the exhaust gas from the rotary kiln is introduced into a catalyst tower containing an oxidation catalyst to treat the exhaust gas.

In the exhaust gas treatment process, as shown in FIG. 1, the exhaust gas discharged from the exhaust pipe 12 is introduced into the catalyst tower 30, and carbon monoxide in the exhaust gas can be reduced and removed.

As the oxidation catalyst, a known catalyst capable of reducing and removing carbon monoxide can be used, and is not particularly limited.

In the reduction treatment method of the present embodiment, as described above, the reaction treatment agent addition step is performed, the desulfurization agent is added to the material to be reduced, and drying and reduction are performed. Therefore, the content of sulfur components in the exhaust gas is reduced, and the oxidation catalyst can be prevented from being poisoned.

According to the reduction treatment method of the present embodiment described above, since the desulfurization agent is added to the material to be reduced in the reaction treatment agent addition step, sulfur components in the exhaust gas can be reduced. Therefore, when performing exhaust gas treatment for reducing carbon monoxide in the exhaust gas, it is possible to suppress poisoning of the oxidation catalyst and efficiently perform the exhaust gas treatment.
[Reduction treatment device]
The reduction processing device of the present embodiment is a reduction processing device that performs reduction processing on a reducible material.

The reduction 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 a reaction treating agent supplying means for supplying a reducing agent and a desulfurizing agent provided in the scoop feeder. and can have The reducing agent is coal, and the desulfurizing agent is quicklime.

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

The reducible substance supplied to the reduction treatment apparatus of the present embodiment is not particularly limited. preferably an object.

Various ores can be mentioned as the material to be reduced. In particular, metal ores that require refining generally contain a lot of water and are oxidized. Further, according to the reduction treatment method of the present embodiment, since drying and reduction can be efficiently performed, it is preferable that the material to be reduced includes metal ore. 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 preliminarily dry the object to be reducible so as to reduce or remove a part of the adhering moisture.

The reduction treatment apparatus of this embodiment can have a rotary kiln, a scoop feeder, and a reaction treatment agent 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 reaction treatment agent supply means 221 is not particularly limited in detail, as long as it is configured to supply the reducing agent and the desulfurization agent, which are the reaction treatment agents.

The reaction treatment agent supply means 221 may have a reducing agent supply means for supplying a reducing agent and a desulfurization agent supply means for supplying a desulfurization agent. may be one reactive processing agent supply means for supplying the

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

The supply amount adjusting means is configured, for example, to be able to adjust the degree of opening of an opening provided on the reaction processing agent supply port 111 side of the storage container in accordance with the supply amount of the reaction processing agent. The supply amount of the dropping reactive treatment agent may be adjusted. Further, the supply amount adjusting means has a conveying means such as a screw conveyor, for example, and is configured to be able to adjust the conveying speed of the reactive treatment agent by the conveying means, and to adjust the supply amount of the reactive treating agent by the conveying speed. You may

Although FIG. 1 shows an example in which the reaction treatment agent supply means 221 is provided in the reaction treatment agent supply port 111, the present invention is not limited to such a configuration. 111 may be connected by piping, and both members may be separated.

The reaction treatment agent supply means can also have a reducing agent supply means for supplying a reducing agent and a desulfurization agent supply means for supplying a desulfurization agent. By having the reducing agent supply means and the desulfurization agent supply means, it is also possible to control the supply amounts of the reducing agent and the desulfurization agent. Each supply means can have, for example, the configuration described for the reaction treatment agent supply means, and the reducing agent supply means and the desulfurization agent supply means may have the same or different configurations.

Since the reducing agent and the desulfurizing agent have already been explained, the explanation is omitted here.

The reduction treatment apparatus of this embodiment can also have a catalyst tower containing an oxidation catalyst for treating the exhaust gas from the rotary kiln.

As the oxidation catalyst, a known catalyst capable of reducing and removing carbon monoxide can be used, and is not particularly limited.

In the reduction treatment apparatus of this embodiment, as described above, the reaction treatment agent is added, the desulfurization agent is added to the material to be reduced, and the material is dried and reduced. Therefore, the content of sulfur components in the exhaust gas is suppressed, and the oxidation catalyst can be prevented from being poisoned.

According to the reduction treatment apparatus of the present embodiment described above, since the desulfurization agent is added to the material to be reduced by the reaction treatment agent addition means, the sulfur component in the exhaust gas can be reduced. Therefore, when performing exhaust gas treatment for reducing carbon monoxide in the exhaust gas, it is possible to suppress poisoning of the oxidation catalyst and efficiently perform the exhaust gas treatment.

10 rotary kiln 130 scoop feeder 30 catalyst tower

Claims (6)

A reduction treatment method for reducing a reducible material in a rotary kiln,
A scoop feeder is provided in the middle of the rotary kiln, and a reaction treatment agent addition step of charging a reducing agent and a desulfurizing agent through the scoop feeder,
The reduction treatment method, wherein the reducing agent is coal and the desulfurizing agent is quicklime. 2. The reduction treatment method according to claim 1, further comprising an exhaust gas treatment step of introducing the exhaust gas from the rotary kiln into a catalyst tower containing an oxidation catalyst to treat the exhaust gas. 3. The reduction treatment method according to claim 1, wherein the material to be reduced contains metal ore. A reduction treatment device for reducing a reducible material,
rotary kiln and
a scoop feeder disposed between longitudinal ends of the rotary kiln;
a reaction treating agent supplying means for supplying a reducing agent and a desulfurizing agent provided in the scoop feeder;
The reduction treatment apparatus, wherein the reducing agent is coal and the desulfurizing agent is quicklime. 5. The reduction treatment apparatus according to claim 4, comprising a catalyst tower containing an oxidation catalyst for treating the exhaust gas from the rotary kiln. 6. The reduction treatment apparatus according to claim 4, wherein the material to be reduced includes metal ore.

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