JP2013128915A - Method and apparatus for treating dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for treating dust, capable of screening, separating and recovering fine coke powder and oxide powder whose main material is iron oxide powder, which are mixed and contained in blast furnace dust, with high accuracy and completeness in industry.SOLUTION: The method for treating dust makes blast furnace dust (a) into slurry c and is adopted in combination with surface reforming treatment and flotation treatment. In other words, the method for treating dust can screen and separate coke powder d and oxide powder e in the blast furnace dust (a), using the difference in wettability between particle surfaces, by performing the following processes: slurrying, oil addition, shearing force application, surface reforming, foaming agent addition, and flotation in order. The apparatus for treating dust can screen and separate coke powder d and oxide powder e in the blast furnace dust (a) by arranging a slurry tank 1, an oil addition means 2, a surface reforming machine 3, a foaming agent addition means 4, and a flotation machine 5 in order.

Description

  The present invention relates to a dust processing method and a dust processing apparatus. That is, the present invention relates to a method and apparatus for selecting and separating coke powder and oxide powder mixed and contained in blast furnace dust.

《Technical background》
As is well known in the blast furnace, iron ore and coke are introduced, and iron ore iron oxide is reduced with carbon monoxide and coke based on coke combustion under the introduction of hot air to obtain metallic iron (pig iron). .
In such iron making, the blast furnace dust contained in the furnace top gas discharged from the top of the blast furnace has been conventionally collected by a dust collector and then discarded. Landfill processing was carried out as industrial waste.

By the way, the following subject was pointed out about such blast furnace dust processing. In blast furnace dust, coke powder and oxide powder mainly composed of iron oxide powder (iron ore powder) are mixed and contained, but these are not effectively used and discarded as blast furnace dust. It was.
That is, coke powder, iron oxide powder, etc. mixed and contained in blast furnace dust are composed of fine particles with a powder diameter of several tens of μm, and are too fine to be industrially impossible to select and separate based on specific gravity. It had been. Coke powder, iron oxide powder, etc. have a large specific surface area per unit mass of particles, have high frictional resistance, float in the air or water, and have been conventionally difficult to select, separate and recover. And was disposed of as blast furnace dust.

<< About the present invention >>
The dust processing method and dust processing apparatus of the present invention have been made in order to solve the above-described conventional problems in view of such a situation.
An object of the present invention is to propose a dust processing method and a dust processing apparatus capable of accurately selecting, separating and recovering coke powder and iron oxide powder in blast furnace dust with high accuracy.

<About each claim>
The technical means of the present invention for solving such a problem is as follows, as described in the claims.
First, claim 1 is as follows.
The dust treatment method according to claim 1 separates and separates coke powder mixed and contained in blast furnace dust and oxide powder mainly composed of iron oxide powder using the difference in wettability of the particle surface. . And it has the following slurrying process, oil addition process, shearing force provision process, surface modification process, foaming agent addition process, flotation process, etc. in order.
In the slurrying step, water is added to the blast furnace dust to form a slurry. In the oil addition step, an oily scavenger is added to the slurry.
In the shearing force application step, a high-speed and strong shearing force is applied to the slurry to which the scavenger is added, and the coke powder, oxide powder, and oil droplets of the scavenger are respectively surface surfaces of the particles. Energy is increased.
In the surface modification step, the hydrophobicity and lipophilicity of the particle surface of the coke powder and oil droplets are further enhanced based on the application of shearing force to the slurry, so that a water film is formed on the particle surface of the coke powder. Instead, the oil droplets are attached as an oil film, and the surface energy is reduced. The oxide powder is further improved in hydrophilicity and oleophobicity on the particle surface, so that it becomes more wet and adaptable to water, and the surface energy decreases.
In the foaming agent addition step, a foaming agent is added to the slurry after the surface modification. In the flotation step, bubbles are generated by blowing or sucking air into the slurry to which the foaming agent has been added. Accordingly, the coke powder floats together with the oil film adhering to the foaming agent around the bubbles, whereas the oxide powder that has become wet with water and settles down.

About Claim 2, it is as follows.
In the dust treatment method of claim 2, in claim 1, in the slurrying step, water is added to the blast furnace dust discharged from the blast furnace, and the blast furnace dust concentration is 10 wt% to 30 wt%. Use slurry.
In the oil addition step, petroleum-based hydrocarbons are added as the scavenger in an addition amount of 0.5 wt% to 10 wt% with respect to the blast furnace dust.
In the shearing force application step, the local packing density and surface energy of each of the coke powder, oxide powder, and oil droplets are transiently increased for each particle based on the dilatancy of the slurry.
In the surface modification step, the hydrophobic bond between the excluded oil droplets and the coke powder is further promoted due to the influence of hydrogen bonding tendency based on the polar molecular structure between water molecules.
In the flotation step, the coke powder that has floated is recovered as a floating product, and the settled oxide powder is recovered as a sedimentation product.

About Claim 3, it is as follows.
The dust processing apparatus according to claim 3 separates and separates coke powder mixed and contained in blast furnace dust and oxide powder mainly composed of iron oxide powder by utilizing the difference in wettability of the particle surface. . And it has the following slurry tank, an oil addition means, a surface modifier, a foaming agent addition means, a flotation machine, etc., It is characterized by the above-mentioned.
In the slurry tank, the supplied blast furnace dust is stirred, mixed, and suspended with water to form a slurry. The oil addition means adds an oil-based scavenger to the slurry supplied from the slurry tank to the surface reformer.
The surface reformer imparts a strong shearing force to the slurry supplied to the stirring chamber in the drum with a stirring blade rotating at high speed to increase the surface energy of the particle surface. Accordingly, the oil droplets of the coke powder and the scavenger are improved in hydrophobicity and lipophilicity, and the oil droplets are attached to the surface of the coke powder particles as an oil film instead of a water film, resulting in low surface energy. Turn into. The oxide powder is improved in hydrophilicity and oleophobicity, becomes more wet and adaptable to water, and the surface energy is reduced. In addition, the hydrophobic bond between the oil droplets and the coke powder is also promoted.
The foaming agent addition means adds the foaming agent to the slurry supplied from the surface reformer to the flotation machine and stirs.
The flotation machine is supplied with the slurry, and air is supplied by blowing or sucking, so that the coke powder floats together with the oil film adhering to the foaming agent around the generated bubbles. The oxide powder that has become wet with water and settles down.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) Blast furnace dust contains coke powder and oxide powder such as iron oxide powder.
(2) Then, after the coke powder is slurried, a collecting agent is added.
(3) Then, the slurry is given a high-speed and strong shearing force, the local packing density of the particles is increased based on the dilatancy, and the surface energy of the particle surface becomes transient due to the surface contact friction between the particles. Enhanced. Thus, the hydrophobic and lipophilic coke powder is attached to the oil droplets of the scavenger as an oil film, and its surface energy is reduced and stabilized, and the oxide has improved hydrophilicity and oleophobicity. Furthermore, the surface energy of the powder decreases and stabilizes when wet and become familiar with water.
(4) The slurry is then floated after the foaming agent has been added and air is blown or sucked. As a result, coke powder adhering to the oil film rises together with the foaming agent around the bubbles, and the oxide powder that has become wet with water and settles down.
(5) And coke powder is collect | recovered as a floating product, and oxide powder is collect | recovered as a sedimentation product.
(6) The dust treatment method of the present invention can be used in a blast furnace dust by following such a slurrying step, an oil addition step, a shearing force application step, a surface modification step, a foaming agent addition step, and a flotation step. The coke powder and the oxide powder can be accurately and reliably separated using the difference in wettability of the particle surface.
(7) Similarly, the dust treatment apparatus of the present invention also comprises a slurry tank, an oil addition means, a surface reformer, a foaming agent addition means, a flotation machine, etc., so that coke powder in blast furnace dust is obtained. And oxide powder can be accurately and reliably separated.
(8) The dust processing method and dust processing apparatus of the present invention exhibit the following effects.

Coke powder and iron oxide powder in blast furnace dust can be accurately selected and separated with high accuracy.
That is, the dust treatment method and dust treatment apparatus of the present invention are characterized in that blast furnace dust is slurried and combined with surface modification and flotation. Therefore, it is possible to industrially select, separate, and recover fine coke powder and iron oxide powder by utilizing the difference in wettability of the particle surface.
Like this type of conventional example described above, the road to effective use is opened without being disposed of as industrial waste. The recovered coke powder is effectively used as fuel, etc., and iron oxide powder can be effectively used for various applications, and feedback to the blast furnace can be considered.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of prior art are solved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system block diagram illustrating a dust processing method and a dust processing apparatus according to the present invention. It is processing explanatory drawing which expanded and displayed the principal part for description of the form for implementing this invention, (1) A figure is a state before surface modification, (2) A figure is a surface modification state, ( 3) The figure shows the flotation state. The surface reformer is shown for explanation of an embodiment for carrying out the invention, (1) FIG. 1 is a side view illustrating a part thereof, (2) FIG. 2 is an XX line in FIG. Fig. 3 is a view taken along the line Y-Y in Fig. 1 (1).

Hereinafter, embodiments for carrying out the present invention will be described in detail.
The dust treatment method of the present invention has a slurrying step, an oil addition step, a shearing force application step, a surface modification step, a foaming agent addition step, a flotation step and the like in order for the blast furnace dust a.
The dust treatment apparatus of the present invention is a slurry tank 1, an oil addition means 2, a surface reformer 3, a foaming agent addition means 4, a flotation machine 5 and the like to which each step of the dust treatment method is applied. In order.
Hereinafter, these will be described.

<< Slurry process >>
First, in the slurrying step of the dust treatment method of the present invention, water b is added to blast furnace dust a to obtain slurry c.
That is, as shown in FIGS. 1 and 2 (1), in the slurry tank 1 of the dust treatment apparatus, the blast furnace dust a discharged and supplied from the blast furnace is stirred, mixed and suspended with the water b. Thus, a slurry c having a blast furnace dust a concentration of 10 wt% to 30 wt% is obtained.

Such a slurrying process will be further described in detail. Blast furnace dust a is supplied to the slurry tank 1 and water b is supplied from the water tank 6 and other water supply equipment, and is stirred to form a water slurry c.
In the blast furnace dust a, coke powder d and oxide powder e are mixed and contained. The coke powder d is fine particles of blast furnace coke obtained by carbonizing caking coal, and the particle size thereof is, for example, about 10 μm or several tens of μm. The unburned carbon that is the coke powder d is roughly grasped as carbon particles, and its chemical substance is a hydrophobic, lipophilic polycyclic aromatic hydrocarbon.
The oxide powder e is mainly composed of iron oxide powder (FeO, Fe ₂ O ₃ fine particles), but also contains lime, silicon, aluminum, other oxide fine particles, and the like.
The blast furnace dust a containing such coke powder d and oxide powder e is supplied so that the concentration in the slurry c stirred with water b is 10 wt% to 30 wt%. When the concentration exceeds 30% by weight, in the surface reforming process using the surface reformer 3, the solidification tendency of the slurry c based on the dilatancy described later becomes remarkable and the fluidity is lost. Cause trouble. On the other hand, when the concentration is less than 10% by weight, there is a problem in terms of profitability, cost, and economy when industrialized, such as a significant decrease in overall efficiency and increased running costs. Therefore, the concentration is typically set to about 15% by weight to 20% by weight from the viewpoint of securing fluidity and economy.
The slurrying process is as described above.

《Oil addition process》
Next, in the oil addition step, an oily scavenger f is added to the slurry c. That is, as shown in FIG. 1 and FIG. 2 (1), the oil collecting means f is applied to the slurry c supplied from the slurry tank 1 to the surface reformer 3 by the oil adding means 2. Added.
As the scavenger f, petroleum-based hydrocarbons or the like are added in an addition amount of 0.5 wt% to 10 wt% with respect to the blast furnace dust a.

Such an oil addition process will be further described in detail. As the scavenger f, petroleum hydrocarbons are typically used. In other words, kerosene, light oil, heavy oil and the like are typically used in view of the fact that the coke powder d, which is a coal-based hydrocarbon, is to be attached.
The collector f is added to the slurry c as a collector oil, and is supplied to the surface reformer 3 as oil droplets g due to interfacial tension. The oil droplets g are subsequently attached to the coke powder d. g ′. The amount of the collection agent f added is very small, and the concentration is 0.5 wt% to 10 wt% with respect to the blast furnace dust a in the slurry c.
When the concentration is less than 0.5% by weight, the amount of the oil film g ′ to be attached to the coke powder d is insufficient in the flotation process using the flotation machine 5 described later, which hinders the flotation of the coke powder d. Occurs. When the concentration exceeds 10% by weight, a liquid surface layer is formed by the excessively added oil droplets g and the like, which hinders the flotation of the coke powder d and hinders the flotation. Furthermore, it is uneconomical and causes problems in terms of cost. In the figure, 8 is a pipe and 9 is a pump.
The oil addition process is as described above.

<< Shearing force application process >>
Next, in the shearing force application step, surface energy is applied to the coke powder d, the oxide powder e, the oil droplet g of the scavenger f, etc. of the slurry c by applying a high-speed and strong shearing force to the slurry c. Will be enhanced.
That is, as shown in FIGS. 1 and 3, the slurry c to which the scavenger f is added as oil droplets g is agitated chamber divided by the partition plate 11 in the cylindrical drum 10 of the surface reformer 3. 12 is supplied. Thus, the oil droplet g of the scavenger f is highly dispersed and mixed in the slurry c by stirring, and the surface energy of the particle surface is transiently increased by applying a shearing force to the slurry c. .

Such a shearing force application step will be further described in detail. First, the surface reformer 3 of FIG. 3 has the following mixer configuration. That is, in the cylindrical drum 10 provided with an inlet and an outlet for the slurry c, a plurality of disc-shaped baffle partition plates 11 are arranged in rows in the horizontal axis direction at equal intervals. The intervals divided by the partition plates 11 are the stirring chambers 12 respectively.
A shaft 14 is provided in the axial direction through the central communication hole 13 of each partition plate 11. A disc-ring shaped stirring plate 15 with a shaft hole is tightly fitted to the shaft 14 for each stirring chamber 12, and substantially arc-shaped and strip-shaped stirring blades 16 are provided on both front and rear surfaces of each stirring plate 15. Each is convex. The shaft 14 is connected to a speed reducer 17 and a motor 18.
Therefore, the slurry c flowing from the upstream agitating chamber 12 to the downstream agitating chamber 12 is given a strong shearing force when the agitating plates 15 and the agitating blades 16 are rotated at high speed by the motor 18. . With respect to the stirring plate 15 and the stirring blade 16, stirring is performed so that the stirring force is, for example, about several thousand rpm and a high stirring rotational speed, and, for example, about several thousand kW / m ³ per unit slurry c amount. To be implemented.
In the illustrated surface reformer 3, a plurality of stirring chambers 12 are separately formed in the cylindrical drum 10, but regardless of this, the stirring plate with the stirring chamber 12 and the stirring blades 16 is provided in the cylindrical drum 10. Of course, a batch-type surface reformer 3 in which only one set 15 is provided is also possible.

In the surface reformer 3, the stirring plate 15 and the stirring blade 16 agitate and rotate so that the coke powder d of the slurry c, the oxide powder e, the oil droplet g of the scavenger f, and the like are mixed into the stirring plate 15 and the stirring blade 16. And the like, and the fixed portion such as the inner surface of the cylindrical drum 10 and the partition plate 11 are forcibly contacted and collided with each other.
Accordingly, the coke powder d, the oxide powder e, the oil droplet g of the scavenger f, and the like are shared and given a high-speed and strong shearing force. Based on the dilatancy of the slurry c, the local packing density and surface energy of each particle are transiently increased (including generation of surface energy).
That is, each particle of the slurry c, which is a dilatant fluid, is increased in concentration and concentration by increasing the packing density in a strong shear force field generated instantaneously in the surface reformer 3. Accordingly, the water b between each other is eliminated, and the surface energy level of the particle surface is increased by forming the shearing surface and the active surface by grinding by surface contact friction between each other.
Therefore, the coke powder d of the slurry c and the oil droplets g of the scavenger f are further improved in the hydrophobicity and lipophilicity of the original particle surface. On the other hand, the oxide powder e further enhances the hydrophilicity and oleophobicity of the original particle surface.
As the dilatancy progresses, the slurry c loses its fluidity and becomes more solidified, but each particle of the slurry c has no water swellability (to the oxide powder e such as iron oxide powder). Since there is no water swellability), the fluidity can be secured up to about 30% by weight as described above.
The shearing force application step is as described above.

<< Surface modification process >>
In the surface modification step, the coke powder d and the oil droplets g are first activated on the particle surface as described above based on the application of the shearing force to the slurry c in the above-described strong shearing force field, and the surface energy level. Is increased transiently, and the hydrophobicity and lipophilicity of the particle surface are further enhanced.
Thus, the coke powder d is peeled off and peeled off the water film adhering to the particle surface in a weak shear force field generated instantaneously and instantaneously in the surface reformer 3 alternately with a strong shear force field. At the same time, the oil droplets g are trapped and become wet, and the oil droplets g form an extremely thin oil film g ′ that adheres to and covers the particle surface. As a result, the coke powder d and the oil film g ′ of the oil droplets g are stabilized by reducing the level of the surface energy.
On the other hand, the oxide powder e is further improved in hydrophilicity and oleophobicity due to the activation of the particle surface and the increase in surface energy, so that the oxide powder e becomes more familiar with the water b. Thereby, the oxide powder e reduces the surface energy level and stabilizes it.
Thus, as shown in FIG. 1 and FIG. 2 (2), in the surface reformer 3, the coke powder d having a higher surface energy is applied to the slurry c based on the shearing force applied to the slurry c. On the other hand, the oil droplets g are trapped to form a thin oil film g ′, which is replaced with a water film and attached. The coke powder d is entirely covered and coated with an oil film g ′, or the oil film g ′ is partially attached.

At the same time, in the surface modification step, the hydrophobic bond between the excluded oil droplet g and the coke powder d is further promoted by the influence of the hydrogen bond tendency based on the polar molecular structure between the water molecules b. However, the adhesion of the oil droplets g to the coke powder d proceeds while being supported.
The hydrophobic intermolecular bond will be described in further detail. In view of the fact that the water molecule b has a high electronegativity of oxygen atoms and a low electronegativity of hydrogen atoms, and there are two pairs of lone pairs in the outer electron structure of the oxygen atoms. Is partially polarized (O ⁻ = 2H ⁺ ).
Therefore, between each water molecule b, an oxygen atom of one water molecule b and a hydrogen atom of another water molecule b tend to attract each other. Such a tendency of hydrogen bonding between water molecules b eliminates the oil droplets g which are non-polar and lipophilic hydrocarbons, so that the oil droplets g repelled between the water molecules b gather on the coke powder d side. To do.
The extremely small amount of oil droplets g is trapped by the coke powder d which is only a small amount and adheres as an oil film g ′. The hydrophobicity and lipophilicity of the coke powder d and oil droplets g described above. In addition to being stirred and dispersed, this point is also supported.
The surface modification process is as described above.

<< Foaming agent addition process >>
Thereafter, the foaming agent h is added to the slurry c after the surface modification in the foaming agent addition step. The slurry c is supplied from the surface reformer 3 to the flotation machine 5 while the surface energy of the coke powder d and oxide powder e particles is reduced. The foaming agent h is added at
As the foaming agent h, MIBC (methyl isobutyl carbinol) and other higher alcohols are used, supplied from the foaming agent tank 19 to the adjustment tank 20, and added in a small amount into the slurry c and stirred. Thus, it is uniformly dispersed in the slurry c.
About the foaming agent addition process, it is as above.

《Flotation process》
Then, in the flotation process, for the slurry c to which the foaming agent h is added, bubbles j are generated by blowing or sucking air i, and thus, together with the oil film g ′ adhering to the foaming agent h around the bubbles j, coke. Powder d rises. On the other hand, the oxide powder e wet and familiar with the water b sinks.

Such a flotation process is further described in detail. As shown in FIGS. 1 and 2 (3), the slurry c is supplied to the flotation machine 5, and the air i is supplied by blowing or sucking. The air i is forcibly blown into the flotation machine 5 or by a mechanical agitation type air supply apparatus that is sucked as the stirring plate 15 in the flotation machine 5 rotates. It is introduced into the flotation machine 5.
Along with the introduction of air i, a thin film is formed with a foaming agent h at the gas-liquid interface of the generated air i particles, and bubbles j of air i are generated. Then, based on the fact that the foaming agent h that forms a thin film around the surface of the bubble j is oleophilic, an oil film g ′ adheres to the thin film of the foaming agent h. Powder d adheres. That is, the coke powder d adheres to the foaming agent h around the bubble j using the oil film g ′ as a binder.
Therefore, as the bubbles j rise and the liquid level floats, the adhering foaming agent h, oil film g ′, and coke powder d also float.
On the other hand, the oxide powder e, which has improved hydrophilicity and oleophobicity and has become familiar with the water b, remains and sinks in the slurry c without adhering to the bubbles j and rising.
The flotation process is as described above.

《Action etc.》
The dust processing method and dust processing apparatus of the present invention are configured as described above. Therefore, it becomes as follows.
(1) Blast furnace dust a contained in the furnace top gas discharged from the top of the blast furnace and collected by the dust collector includes coke powder d and oxide powder e mainly composed of iron oxide powder (iron ore powder). , Mixed, contained.

  (2) Then, after such coke powder d is suspended in water to form a slurry c, an oil-based scavenger f is added in a small amount to the slurry c to form oil droplets g (FIG. 2). (1) Refer to the figure).

(3) Then, the slurry c is given a high-speed and strong shearing force in a strong and high shearing force field, so that the local packing density of the particles is increased based on the dilatancy, and the surface contact friction between the particles is increased. Thus, the surface energy of each particle surface is transiently increased.
Accordingly, the coke powder d and the oil droplets g in the slurry c are further improved in hydrophobicity and lipophilicity, and the oil droplets g and the oil film g ′ are formed on the coke powder d by the interaction between particles in a weak shear force field. It adheres and lowers and stabilizes its own surface energy (hydrophobic bonds also support this). The oxide powder e in the slurry c, whose hydrophilicity and oleophobicity are further enhanced, is further reduced in its own surface energy and stabilized by being wet-accustomed to water (see FIG. 2 (2)). ).

(4) The surface of the slurry c is modified in this way, and the surface energy of the particle surface is reduced. After the foaming agent h is added, the air i is blown or sucked and subjected to a flotation process. .
Accordingly, the foaming agent h, the oil film g ′, and the coke powder d rise together with the generated bubbles j, while the hydrophilic oxide powder e that has become wet and familiar with the water b sinks.
The coke powder d is further improved in hydrophobicity due to the adhesion of the oil film g ′, and a flotation process with high sorting accuracy is realized in view of its water repellency (see FIG. 2 (3)).

(5) The floated coke powder d is recovered as a floating product of the flotation floss, and the settled oxide powder e is recovered as a sedimentation product of the flotation tailing.
The coke powder d and iron oxide powder (FeO, Fe ₂ O ₃ fine particles) recovered in this way are solid-liquid separated from water b by a filter, a concentrator, a filter press, etc., dehydrated and dried, It is used effectively.

(6) The dust treatment method of the present invention follows such a process such as a slurrying step, an oil addition step, a shearing force application step, a surface modification step, a foaming agent addition step, and a flotation step in order. The coke powder d mixed and contained in the blast furnace dust a and the oxide powder e mainly composed of iron oxide powder are accurately and reliably selected using the difference in wettability of each particle surface. Separable.
The coke powder d in the slurry c and the iron oxide powder of the oxide powder e are made of fine particles and have a large specific surface area per unit mass. It is difficult to make it. However, as described above, by slurrying and surface modification treatment and then flotation treatment, it becomes possible to select and separate using the difference in wettability.

(7) The same applies to the dust treatment apparatus of the present invention. In other words, this dust treatment apparatus comprises a slurry tank 1, an oil addition means 2, a surface reformer 3, a foaming agent addition means 4, a flotation machine 5 and the like arranged in this order in the blast furnace dust a. Coke powder d and oxide powder e can be accurately and reliably selected and separated.
The operation of the present invention is as described above.

DESCRIPTION OF SYMBOLS 1 Slurry tank 2 Oil addition means 3 Surface reformer 4 Foaming agent addition means 5 Flotation machine 6 Water tank 7 Oil tank 8 Piping 9 Pump 10 Cylindrical drum 11 Partition plate 12 Stirring chamber 13 Central communication hole 14 Shaft 15 Stirring plate 16 Stirring Blade 17 Reduction gear 18 Motor 19 Foaming agent tank 20 Adjustment tank a Blast furnace dust b Water c Slurry d Coke powder e Oxide powder f Collection agent g Oil droplet g 'Oil film h Foaming agent i Air j Bubble

Claims (3)

A dust treatment method for selecting and separating coke powder mixed and contained in blast furnace dust and oxide powder mainly composed of iron oxide powder using the difference in wettability of the particle surface,
A slurrying step of adding water to the blast furnace dust to form a slurry; an oil addition step of adding an oil-based scavenger to the slurry;
Giving a high-speed and strong shearing force to the slurry to which the scavenger is added, and imparting a shearing force to increase the surface energy of the particle surface of the coke powder, oxide powder, and oil droplets of the scavenger, respectively. Process,
Based on the application of shearing force to the slurry, the coke powder and oil droplets are further improved in hydrophobicity and lipophilicity on the particle surface, so that the oil droplets become oil films on the coke powder particle surfaces instead of water films. The surface energy is reduced, and the oxide powder is further improved in the hydrophilicity and oleophobicity of the particle surface, so that the surface energy is reduced by being more wet and familiar with water. ,
A foaming agent addition step of adding a foaming agent to the slurry after the surface modification, and bubbles are generated by blowing or sucking air into the slurry to which the foaming agent is added. The coke powder floats together with the oil film adhering to the foaming agent, while the oxide powder that has become wet with water settles down, and has a flotation step. Processing method. In claim 1, in the slurrying step, water is added to the blast furnace dust discharged from the blast furnace to form the slurry having a blast furnace dust concentration of 10 wt% to 30 wt%.
In the oil addition step, petroleum-based hydrocarbons are added as the scavenger in an addition amount of 0.5 wt% to 10 wt% with respect to the blast furnace dust,
In the shearing force application step, on the basis of the dilatancy of the slurry, the local packing density and surface energy of each of the coke powder, oxide powder, and oil droplets are transiently increased for each particle,
In the surface modification step, the hydrophobic bond between the excluded oil droplets and the coke powder is further promoted by the influence of the hydrogen bonding tendency based on the polar molecular structure between water molecules,
In the flotation step, the raised coke powder is collected as a floating product, and the settled oxide powder is collected as a precipitated product. A dust treatment device that separates and separates coke powder mixed and contained in blast furnace dust and oxide powder mainly composed of iron oxide powder using the difference in wettability of the particle surface,
The supplied blast furnace dust is agitated, mixed and suspended with water to make a slurry tank, and an oil-based collector is added to the slurry supplied from the slurry tank to the surface reformer. Oil adding means to
The slurry supplied to the stirring chamber in the drum is given a strong shearing force by a high-speed rotating stirring blade to increase the surface energy of the particle surface. , Hydrophobicity and lipophilicity are enhanced, the oil droplets are attached to the surface of the coke powder particles instead of a water film, and the surface energy is reduced, and the oxide powder is hydrophilic and oleophobic. The surface modifier, wherein the surface energy is reduced by being more wet and familiar with water, the surface energy is reduced, and the hydrophobic bond between the oil droplets and the coke powder is also promoted.
A foaming agent adding means for adding and stirring a foaming agent to the slurry supplied from the surface reformer to the flotation machine,
As the slurry is supplied, air is supplied by blowing or sucking, so that the coke powder floats along with the oil film adhering to the foaming agent around the generated bubbles, and wets and adjusts to the water. And a flotation device for sinking the oxide powder.

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