JP5167608B2 - Dust sintering method - Google Patents

Description

The present invention relates to how to produce a sintered ore using a dust containing zinc generated in steelworks.

Various types of dust are generated in the steelworks, and these dusts are collected and reused from the viewpoint of effective use of resources and environmental measures.
Under such a background, conventionally, a method for recovering zinc from dust containing zinc is known (for example, Patent Document 1).

This conventional method is performed by the following procedure.
(1) To the zinc-containing dust, a carbonaceous reducing agent and a low zinc-containing substance are added in a kneader to adjust the contents of carbon and zinc.
(2) The dust whose carbon and zinc contents are adjusted is formed into a group mineral by a grouping machine, and the surface of the group mineral is covered with a calcium compound.
(3) The group mineral whose surface is coated with the calcium compound is sent to the sintering machine and supplied in a layered manner between the sintering raw material and the flooring ore in the sintering machine.
(4) The sintering raw material supplied to the sintering machine is first ignited at the upper surface by an ignition furnace, and then heated while moving on the sintering machine. It becomes ore and is carried out of the sintering machine.

For this reason, the combustion of the packed bed of zinc-containing nodule mineral charged in the lowermost layer of the sintering raw material occurs near the exhaust side. When the zinc-containing nodule mineral starts to burn, the zinc oxide in the nodule mineral is reduced and evaporated as metallic zinc. The evaporated metal zinc is oxidized to become zinc oxide again, and is guided to the dust collector together with dust generated during the sintering process.
At this time, by collecting the exhaust gas when the packed bed of zinc-containing nodule mineral burns and separating it from other exhaust gas at that time, the dust with a high zinc concentration is selectively collected. Can do.
JP-A-6-330198

However, in the conventional method, it is necessary to add (1) a carbonaceous reducing agent and a low zinc-containing substance to the zinc-containing dust to adjust the contents of carbon and zinc. In addition, (2) dust whose carbon and zinc contents are adjusted is formed into a group mineral by a grouping machine, and the surface of the group mineral needs to be covered with a calcium compound.
For this reason, in a conventional method, it is necessary to pre-process about zinc containing dust, and there exists a malfunction that zinc containing dust cannot be used as it is.

When the present inventor intends to re-process iron-making dust containing zinc, the pre-treatment of the zinc-containing dust is performed as described above, and normal granulation is performed. It was found that if it was inserted as it was, it was effective for dezincification of dust.
Based on this knowledge, the inventor has advanced earnestly research, and in the research, examined the sintering process in the sintering machine when the recovery of the conventional zinc-containing dust is not considered.

A schematic diagram of the sintering state in such a sintering process is as shown in FIG.
More specifically, the solid fuel in the sintered raw material is ignited in an ignition furnace, and sintering proceeds from the upper side to the lower side while forming a sintered molten zone of the sintered raw material. Here, the sintered layer is the sintered cake, the layer in which the sintering is in progress is the melting zone, and the lower side is a state where there is a lot of moisture formed by the moisture in the sintering raw material moving downward by evaporation Called the wet zone.
In this sintering, the sintered raw material receives a thermal history as shown in FIG. 3B, for example, becomes a sintered cake, and is crushed at the sinter machine ore portion to become a sintered ore. Here, FIG. 3B shows the temperature distribution in the broken line part of FIG.

An example of the yield distribution of sintering in the cross section of the sintering raw material in the sintering pallet corresponding to FIG. 3B is as shown in FIG. In FIG. 3C, each numerical value indicates a yield. According to this figure, it can be seen that the yield is worse toward the surface layer side of the sintered raw material and toward both sides of the pallet.
In particular, both sides of the pallet (sidewall) are subject to volume shrinkage due to the sintering raw material being fired during the combustion process, so that the atmosphere is easily sucked, and ignition and quenching occur. I can think of it.

As a result of such studies, when the steelmaking dust containing zinc is used as it is without pretreatment, the dust charging position is excluded from the vicinity of the side wall of the sintered pallet. In the region, it was found that the dust can be subjected to a high temperature thermal history and the evaporation of the zinc contained in it can be reliably realized.
Accordingly, the object of the present invention has been completed based on the above-mentioned knowledge, and does not require pretreatment of zinc-containing dust, and the dust sintering method and sintering method that can reliably realize dezincification. It is to provide a machine.

The present invention has been completed based on the above findings, and has the following configuration.
That is, the first invention is a sintering method in which a desired sintered ore is sintered using zinc-containing dust and a normal sintering raw material, and the floor ore is supplied into the pallet. A first step of forming a first layer having a predetermined thickness, and zinc on the first layer in the pallet, excluding the vicinity of the side wall of the pallet, containing zinc Without adding a carbonaceous reducing agent and a low zinc-containing substance, without adjusting the carbon and zinc content, the surface of the dust group mineral formed on the group mineral by the grouping machine is made with calcium compounds. A second step of forming a second layer having a thickness of 15 mm or less by supplying without coating, and supplying the ordinary sintering raw material on the second layer in the pallet; A third layer having a thickness relatively greater than the thickness of the second layer; And moving the pallet, and during the movement, air is sucked from the upper side of the third layer toward the lower side of the first layer, and the solid in the normal sintering raw material And a fourth step of sequentially heating each layer by burning the fuel.

The second invention is the length corresponding to the length direction between the sidewalls of the pallet of the second layer, where B is the length between the sidewalls at the bottom of the pallet in the first invention. If A is A, A / B is set to 0.7 or more and 0.8 or less.

  According to the present invention, when a desired sintered ore is obtained using a dust containing zinc and a normal sintering raw material, the zinc-containing dust is not required to be pretreated and dezincified. Can be realized reliably.

Hereinafter, embodiments of a dust sintering method and a sintering machine according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the overall configuration of the sintering machine of the present invention.
The embodiment according to the sintering machine of the present invention has been completed based on the above findings, and is configured as follows.

That is, the sintering machine according to this embodiment includes a movable sintering pallet 11 as shown in FIG. Specifically, the sintering pallet 11 can move around the pair of pulleys 12a and 12b at a predetermined speed during a sintering operation.
Moreover, the sintering pallet 11 is configured such that the bottom thereof can be ventilated, and includes side walls 41A and 41B on both sides in the width direction (see FIG. 2), and contains the bedding or zinc as described later. Dust and sintering raw material to be supplied are supplied.

On the upper side of the sintering pallet 11, along with the moving direction of the sintering pallet 11, a flooring ore supply device 13, a dust supply device 14, a sintering raw material supply device 15, and an ignition furnace 16 are arranged. Yes.
The flooring ore supply device 13 supplies the flooring ore in a layered manner to the bottom of the sintering pallet 11 to form a flooring ore layer 31 having a predetermined thickness as shown in FIG. To do.

The dust supply device 14 is configured to deposit dust containing zinc in a region on the center side excluding the vicinity of the sidewalls 41A and 41B on both sides of the sintering pallet 11 on the flooring ore layer 31 in the sintering pallet 11. It supplies so that it may become layered, and forms the dust layer 32 of predetermined thickness as shown in FIG.2 (B).
The dust forming the dust layer 32 is preliminarily granulated so as not to deteriorate the air permeability in the sintering operation, and the above granulation is sufficient by a normal granulation method.

  That is, dust generated from a blast furnace, a converter, etc. is collected by a wet and / or dry method, and a binder is added to and mixed with the collected dust, granulated and dried in a rotary kiln, and the dust supply device 14 For example, the dust is granulated by inserting and inserting it into a predetermined position of the flooring ore layer 31, for example, from iron-making dust disclosed in JP-A-7-138660, JP-A-7-242954, and the like. Ordinary granulation techniques such as a method for producing a sintered raw material can be used.

A normal raw material is supplied in a layered form on the dust layer 32 in the sintering material supply device 15 and the sintering pallet 11, and the raw material having a predetermined thickness as shown in FIG. The layer 33 is formed. Here, the sintering raw material layer 33 is relatively thicker than the thickness of the dust layer 32.
The ignition furnace 16 is for igniting the solid material in the sintering material layer 33 formed in the sintering pallet 11.

  A large number of window boxes 17 are arranged on the lower side of the sintering pallet 11 and can be sucked from the large number of window boxes 17 via the exhaust gas duct 18 and the exhaust gas dust collector 19 by the suction exhaust fan 20. For this reason, when the surface of the sintering raw material layer 33 in the sintering pallet 11 is ignited by the ignition furnace 16, the sintering raw material layer 33 sequentially burns from the upper side to the lower side during the circular movement of the sintering pallet 11. Can be done.

Therefore, the ignition furnace 16, the window box 17, the exhaust gas duct 18, the exhaust gas dust collector 19, the suction exhaust fan 20, and the like form a sintering processing unit.
Next, a method for obtaining a desired sintered ore using a dust containing zinc and a normal sintering raw material using the sintering machine according to the embodiment having such a configuration will be described with reference to FIGS. This will be described with reference to FIG.

In this sintering machine, the sintering pallet 11 is rotated (moved) at a predetermined speed by a drive motor (not shown) during use. During the circular movement of the sintering pallet 11, each device performs the following operations.
First, the bedding ore supply device 13 supplies the bedding ore in a layered manner to the bottom of the sintering pallet 11. For this reason, a floor covering ore layer 31 having a predetermined thickness is formed at the bottom of the sintering pallet 11 as shown in FIG.

When the flooring ore layer 31 reaches the position of the dust supply device 14 with the movement of the sintering pallet 11, the dust supply device 14 is located in the sintering pallet 11 and on the flooring ore layer 31. The dust containing is supplied in layers.
However, in this case, the dust supply device 14 contains zinc in the region on the center side excluding the vicinity of the sidewalls 41A and 41B on both sides of the sintered pallet 11 on the floor covering ore layer 31. Dust is supplied in layers. For this reason, a dust layer 32 having a predetermined thickness as shown in FIG. 2B is formed on the floor covering ore layer 31.

When the dust layer 32 reaches the position of the sintering material supply device 15 with the movement of the sintering pallet 11, the sintering material supply device 15 is in the sintering pallet 11 and on the dust layer 32. A normal sintering raw material is supplied in layers. For this reason, a sintering material layer 33 having a predetermined thickness as shown in FIG. 2C is formed on the dust layer 32.
Further, when the sintering pallet 11 moves and the three layers 31 to 33 reach the position of the ignition furnace 16, the surface of the sintering raw material layer 33 is ignited by the ignition furnace 16. Therefore, during the movement of the sintering pallet 11, air is sucked from the upper side of the sintering raw material layer 33 toward the flooring ore layer 31 by the suction exhaust fan 20, and the solid fuel in the sintering raw material burns. Each layer is heated sequentially. Then, after the combustion of the lowermost layer is completed, the sintering raw material and the like become sintered ore and are discharged from the sintering pallet 11.

For this reason, the combustion of the dust layer 32 made of zinc-containing dust occurs near the exhaust side. When the dust layer 32 starts to burn, zinc oxide in the dust is reduced and evaporated as metallic zinc. The evaporated metallic zinc is oxidized to become zinc oxide again, and is led to the dust collector 20 together with new dust generated in the sintering process.
Here, in this embodiment, the dust layer 32 containing zinc formed in the sintering pallet 11 is inserted between the flooring ore layer 31 and the sintering raw material layer 33, and A region on the center side excluding the vicinity of the sidewalls 41A and 41B, that is, a region that becomes high in the sintering process was formed (see FIG. 2C).

Therefore, the length in the width direction at the bottom of the sintering pallet 11 (the length between the side walls 41A and 41B) is B, and the length corresponding to the width direction of the sintering pallet 11 in the dust layer 32 that becomes high temperature during the sintering process. When A is B, A / B is preferably 0.7 or more and 0.8 or less. The reason is as follows.
That is, the air drawn downward along the side walls 41A and 41B of the sintering pallet 11 is lower in temperature than other parts due to volume shrinkage during sintering of the sintered raw material, and passes through the air. High oxygen content in (combustion gas). For this reason, if the iron-making dust containing zinc is arrange | positioned in this area | region (site | part), reoxidation will arise and dezincing will become unstable.

Therefore, in this embodiment, the vicinity of the side walls 41A and 41B of the sintering pallet 11 having such a defect is removed, and the dust containing zinc is placed between the flooring mineral layer 31 and the sintering raw material layer 33. Inserted. Thereby, the dust containing zinc receives the high temperature thermal history, and can implement | achieve evaporation of the zinc contained in it reliably.
When the total thickness of the three layers 31 to 33 is about 600 mm, the thickness of the dust layer 32 is preferably set to 15 mm or less so that a high temperature time can be maintained. The thickness is preferably 10 mm or less.

As described above, in this embodiment, based on the above knowledge, the dust layer 32 containing zinc formed in the sintering pallet 11 is disposed between the flooring ore layer 31 and the sintering raw material layer 33. And formed in a central region excluding the vicinity of the sidewalls 41A and 41B of the sintering pallet 11 (see FIG. 2C).
For this reason, according to this embodiment, when obtaining a desired sintered ore using dust containing zinc and a normal sintering raw material, pretreatment is not required for the zinc-containing dust. Thus, dezincification can be realized with certainty.

It is a side view which shows the structure of embodiment of the sintering machine of this invention. It is explanatory drawing explaining the formation method of the flooring ore layer, dust layer, and sintering raw material layer with respect to a sintering pallet. It is the examination figure examined in order to complete this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Sintering pallets 12A and 12B Pulley 13 Floor covering ore supply apparatus 14 Dust supply apparatus 15 Sintering raw material supply apparatus 16 Lighting furnace 17 Window box 18 Exhaust gas duct 19 Exhaust gas dust collector 20 Suction exhaust fan 31 Floor covering ore layer 32 Dust layer 33 Sintering Raw material layer 41A, 41B Side wall

Claims (2)

A sintering method in which a desired sintered ore is sintered using zinc-containing dust and a normal sintering raw material,
A first step of supplying a flooring ore into a pallet to form a first layer having a predetermined thickness;
On the first layer in the pallet, the dust containing zinc is added to the central region excluding the vicinity of the side wall of the pallet without adding a carbonaceous reducing agent and a low zinc-containing substance. The second layer having a thickness of 15 mm or less is supplied by supplying the surface of the dust group mineral formed on the group mineral by the grouping machine without covering with the calcium compound without adjusting the carbon and zinc contents. A second step of forming;
A third step of supplying the normal sintering raw material onto the second layer in the pallet to form a third layer having a thickness that is relatively greater than the thickness of the second layer. When,
The pallet is moved, and during the movement, air is sucked from the upper side of the third layer toward the lower side of the first layer, and the solid fuel in the normal sintered raw material is burned to sequentially move the layers. A fourth step of heating;
A dust sintering method comprising:   When the length between the sidewalls at the bottom of the pallet is B, and A is the length corresponding to the length direction between the sidewalls of the pallet of the second layer, A / B is 0.7. The dust sintering method according to claim 1, wherein the dust sintering ratio is 0.8 or more.

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