KR100924296B1 - Process for preparing zinc sulfate from electric arc furnace dust, and an apparatus therefor - Google Patents

Abstract

PURPOSE: An apparatus for preparing zinc sulfate from electric arc furnace dust(EAFD) is provided to increase zinc yield by allowing atomized concentrated sulfuric acid particles to react to dust powder uniformly. CONSTITUTION: An apparatus for preparing zinc sulfate from electric arc furnace dust(EAFD) comprises the following units. A reactor(10) includes a gas discharge pipe(11) at the top, and discharge unit(60) connected to a depot(61) at the bottom. A first input pipe(21) has a nozzle(22) for spraying concentrated sulfuric acid. A second input pipe(32) is installed on the top of the reactor and inputs EAFD. A vibration tray(40) is installed on the top of the reactor to accommodate EAFD, and includes a plurality of holes(41) at the bottom.

Description

Process for producing zinc sulfate from electric dust and apparatus therefor {PROCESS FOR PREPARING ZINC SULFATE FROM ELECTRIC ARC FURNACE DUST, AND AN APPARATUS THEREFOR}

The present invention is to install a vibrating plate that is a spray means of concentrated sulfuric acid and electric dust dust in the reactor to induce uniform mixing of the concentrated sulfuric acid and the dust of the electric furnace, and also to collect the mixture in a rotary disk equipped with a mill, the secondary reaction The present invention relates to a zinc device capable of producing a high yield and rapid production of zinc sulfate components, and to a method for producing zinc sulfate using the same.

In general, zinc sulfate is prepared by directly reacting with sulfuric acid or hydrochloric acid using zinc metal, but since zinc metal is expensive, it is not economically advantageous to prepare such a compound. Therefore, the use of waste to recover the zinc contained in the waste to replace the expensive metal zinc, this method protects the environment and economically advantageous because the research on waste continues.

Among the wastes presently, it is advantageous to use a large amount of generated electric dust (EAFD), but manufacturing with such wastes has several limitations. That is, the conventional electric furnace dust can not be used as it is, it has been used through the disposal of special industrial waste companies or mixed with asphalt mortar, but the waste due to various heavy metals generated in the leachate, and also contains the heavy metal so leached When the dried solution is dried, fine powder is scattered and adversely affects the human body, which is a social problem.

Furnace dust is generated from scrap metals such as scrap cars due to evaporation of zinc in high temperature electric furnace at 1800 ℃ or in scrap cars, and its components are different depending on the type of scrap and the manufacturing characteristics of the processing company. In most cases, iron is about 20-35%, zinc is about 20-35%, and other aluminum, silica, various inorganic salts, copper and magnesium salts are present.

The present inventors have applied for various patents on the method of recovering zinc from dust or zinc material (Patent Documents 1 to 6, etc.). The patent documents propose methods for producing metal zinc or zinc compounds by treating dust with electricity. However, when the zinc compound is prepared, since the iron component is contained in an amount similar to that of zinc, When sulfuric acid or hydrochloric acid is used to react with the dust, there is a problem that not only zinc in the dust but also iron components are reacted together.

When the dust is analyzed and reacted with sulfuric acid or hydrochloric acid at an equivalent ratio of zinc content in the dust, the zinc component reacts with the acid to obtain zinc sulfate or zinc chloride, but the zinc and iron components in the dust do not exist independently. The reaction time is too long even in the reaction with strong acid, and the zinc compound contains about 4 to 5% of iron in zinc form. If zinc oxide is not used for iron removal, pure zinc compounds cannot be obtained.

In addition, the de-ironing process is expensive, and thus, there is no price competitiveness in the method for producing a zinc compound such as zinc sulfate or zinc chloride, which is a final compound. In particular, in Patent Document 3, which the inventors have applied for, the reducing agent is mixed with the electric dust, and sulfuric acid is added thereto to obtain zinc sulfate and ferrous sulfate, and after separating, the sulfuric acid agent 1 contained in a small amount in zinc sulfate. Although a method of manufacturing zinc sulfate by removing iron has been disclosed, such a method has a high facility cost, a complicated process due to the cost of ferrous sulfate filtration, a separation process, and a decarburization, and a high cost. have.

In addition, the present inventors to suppress the conversion of iron components to iron sulfate or iron chloride in the recovery of zinc sulfate by reacting the dust with a strong acid such as hydrochloric acid or sulfuric acid in order to solve this problem, and selectively only zinc salt In order to recover, a small amount of copper sulfate or copper chloride is added to react to inhibit the formation of iron sulfate or iron chloride by the catalytic action of copper sulfate or copper chloride, and a patent application has been applied for recovering only zinc sulfate or zinc chloride (Patent Document 4). However, the conventional method described above requires a long time to recover zinc contained in the dust because zinc ferrite does not react well with acid, or more than about 50% of zinc may be discharged as it is, without reacting. Since they are all wet reactions, they cannot be carried out in batch reactions in a continuous manner, resulting in a high labor cost and thus not an economically satisfactory method.

Accordingly, the present inventors continuously supply the dust and concentrated sulfuric acid to the reactor equipped with the rotating disk through the first hopper and the sulfuric acid injection tube to react these raw materials in a finely pulverized state to obtain a reaction mixture of zinc sulfate. By removing the harmful gas generated by the reaction through cyclone, zinc sulfate can be recovered at high speed, and lining the inside of the reactor with acid resistant materials such as glass fiber reinforced plastic or Teflon can greatly extend the life of the reactor. A method for recovering a zinc component from an electric dust and a device therefor, which can manufacture these devices at low cost, has been proposed (Patent Document 6). However, in this method, since the particle size of concentrated sulfuric acid and the dust of the electric furnace is uneven and the centrifugal force is applied, the reaction zone is mainly concentrated on the inner wall of the reactor. After treatment, the dust must be reacted and the dust sprayed by the rotation of the rotating plate does not necessarily react uniformly with sulfuric acid, and there is still a part to be improved.

[Patent Documents]

1. Republic of Korea Patent Application No. 1998-0012296

2. Korean Patent Application No. 1998-0015857

3. Republic of Korea Patent Application No. 1998-0039927

4. Republic of Korea Patent Publication No. 2001-0098080

5. Korean Patent Application No. 2006-0110962

6. Republic of Korea Patent Publication No. 2009-0013495

An object of the present invention devised to solve the above problems is to spray concentrated sulfuric acid into the mist phase in the reactor, and to uniformly mix and react the electric dust and concentrated sulfuric acid by uniformly dispersing and dropping the electric dust powder by the vibration plate. In addition, the mixture is collected in a rotating plate formed with a mill and pulverized again, to provide a secondary reaction by maximizing the reaction efficiency and mechanically stable electric dust dust dissolution reaction apparatus and a method for producing zinc sulfate using the same.

Electric furnace dust reaction apparatus of the present invention for achieving the above object, the gas discharge pipe 11 is provided at the top, the reactor 10 is provided with a discharge means 60 connected to the storage tank 61 at the bottom, and A first inlet tube 21 having a nozzle 22 installed above the reactor 10 to spray concentrated sulfuric acid into a mist, and a second inlet tube installed above the reactor 10 to inject dust into an electric furnace; And a vibrating plate 40 installed around the nozzle 22 to receive the electric dust and having a plurality of holes 41 formed on a bottom thereof and capable of reciprocating in the horizontal direction.

As a preferred embodiment, a rotary mill 54 is rotated by a rotary driving means 54 under the reactor 10 and is provided with a cylindrical mill 52 that is pressed and rotated in contact with one side of the upper surface to pressurize and stir the dust reactant with concentrated sulfuric acid. Characterized in that 50 is provided.

According to the present invention, the concave-convex portion 51 is formed on the upper surface of the rotating plate 50, or a plurality of protrusions 53 are formed on the outer surface of the mill 52 in the longitudinal direction to react the concentrated sulfuric acid with the electric dust. Can improve.

In addition, the vibration drive of the vibration plate 40, the link bar 42 is connected to one side of the vibration plate 40 and the other side of the link bar 42 is connected to an eccentric position in the center of the cam 43 By virtue of the rotation of the cam 43, the diaphragm 40 can be reciprocated.

On the other hand, the electric furnace dust dissolving method of the present invention for achieving the above object, sprays concentrated sulfuric acid into the fog through a nozzle installed on the reactor top, reciprocating in the horizontal direction around the nozzle and a plurality of holes formed on the bottom surface Electric dust is introduced into the vibrating plate, and the powder of the electric dust discharged through the hole and the sprayed concentrated sulfuric acid are mixed and reacted.

A more preferable method for dissolving dust in an electric furnace is characterized in that the mixture of the dust and the concentrated sulfuric acid in the electric furnace is collected in a rotary disk in which a mill is formed, and the mixture is regrinded between the mill and the rotary disk for secondary reaction.

According to the present invention, the concentrated sulfuric acid is sprayed into the mist phase through the nozzle in the reactor and at the same time, the electric dust is uniformly dispersed and dropped by the hole formed in the hole, the atomized concentrated particles and the electric dust powder uniformly Because of the mixing and reaction, it is possible to increase the zinc yield in the electric dust (EAFD) as a raw material.

Moreover, it is a very effective invention which can raise reaction efficiency through the secondary reaction process which collects electric dust and a concentrated conversion mixture into the rotating disk which mill was formed, and pressurizes and stirred once more.

In general, when the dust is treated with sulfuric acid by electricity, in the case of dust components, that is, iron 30% and zinc 30%, the component ratios of iron sulfate and zinc sulfate are generated at similar levels. In order to avoid this, only zinc having a high activity can be recovered by using an equivalent amount of sulfuric acid as an equivalent ratio to zinc content, but in reality, a large amount of iron is reacted together with zinc, and when sulfuric acid is added, iron sulfate, Since zinc sulfate is recovered at about the same level, and the solution specific gravity of iron sulfate and zinc sulfate is similar, when zinc sulfate is used as a target product, iron components are completely removed and filtered to induce high purity zinc sulfate. Because of the high cost of decarburization in the process, zinc sulfate is not competitive due to its cost share. In this way, when sulfur and zinc components in dust react with sulfuric acid, concentrated sulfuric acid (98%) is added in an amount of 1.4 to 1.8 weight ratio based on the amount of zinc components in dust to avoid simultaneous dissolution of iron and zinc components. When added, zinc is converted to zinc sulfate, and some iron is converted to iron sulfate, which is converted to zinc sulfate and iron oxide (Fe ₂ O ₃ ) by reaction with unreacted zinc or zinc compounds.

In using such a method, the reactor of the present invention is provided with a nozzle for spraying mist in order to atomize concentrated sulfuric acid at the top, and a vibration plate for spraying and dropping electric dust into powder. In addition, in order to increase the reaction efficiency of the mixture of the dust powder and concentrated sulfuric acid particles, a rotary plate equipped with a mill is provided at the bottom of the reactor.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3 showing examples of the dissolution apparatus of the present invention.

1 is a schematic view showing a reaction apparatus of an electric furnace dust according to an embodiment of the present invention, Figure 2 is a partial perspective view showing the structure of a vibration plate of the melting apparatus of the electric furnace dust according to an embodiment of the present invention, Figure 3 is a partial perspective view showing the structure of the rotating plate of the reaction apparatus of the electric dust according to an embodiment of the present invention.

Referring to FIG. 1, a first input pipe 21 and a second hopper may be disposed at an upper portion of the reactor 10 to introduce concentrated sulfuric acid (H ₂ SO ₄ ) stored in the first hopper 20 into the reactor 10. 30 is provided with a second input pipe 32 for introducing the electric furnace dust (EAFD) stored in the reactor 10, the second input pipe 32 and the screw and to smoothly transfer the dust in the electric furnace The same transfer means 31 may be provided.

In addition, the upper end of the reactor 10 is provided with a discharge pipe 11 connected to the intake pump 12, the discharge pipe 11 discharges the hydrogen chloride (HCl) gas generated in the reactor 10 during the electric dust and sulfuric acid reaction It is a pipeline to make. Of course, although not shown, the discharge pipe 11 may be provided with a dust collecting facility for treating the harmful substances of the hydrogen chloride gas.

At the bottom of the reactor 10, zinc sulfate (ZnSO ₄ ), iron oxide (Fe ₂ O ₃ ), and the like (hereinafter, abbreviated as 'reactants') obtained by the reaction between dust and concentrated sulfuric acid are transferred to the storage tank 61. Ejection means for 60 is provided.

In order to increase the reaction efficiency of the electric dust and concentrated sulfuric acid, the upper part in the reactor 10 is provided with a diaphragm 40, in addition to the rotary disk 50 is provided with a mill 52 at the bottom Can be.

As shown in FIG. 2, the diaphragm 40 is a dish-shaped mesh that receives dust from electricity introduced from the second input pipe 32, and a plurality of holes 41 are formed at a bottom thereof. Of course, the hole 41 may be replaced by a mesh-type mesh, and in the case of the size of the hole 41 or the mesh, a mesh size of about 0.5 mm is suitable, but is not limited thereto.

The vibration plate 10 has a link bar 42 connected to a side thereof, and the other end of the link bar 42 is connected to an eccentric position at the center of the cam 43 as shown in FIG. 1. In such a configuration, when the cam 43 rotates about the central axis by a driving means such as a motor (not shown), the link bar 42 connected to the eccentric position is switched to reciprocating movement, whereby the link bar ( The vibrating plate 40 connected to 42 is reciprocated in the horizontal direction to allow vibration movement.

The reciprocating feed speed of the diaphragm 40 is determined by the rotational speed of the cam 43. For example, when the cam 43 rotates at a speed of 120 rpm, the diaphragm 40 is 240 per minute in the horizontal direction. Is transported twice. Due to the vibration action, the electric dust contained in the vibration disk 40 is powdered through the hole 41 in the bottom of the vibration disk 40 to fall down the reactor 10, and the distribution of the electric dust is By vibrating action, it is scattered all over the reactor. Of course, the vibration structure of the vibration plate 40 is not limited to the illustrated embodiment, and may be replaced with another known vibration structure.

In addition, the concentrated sulfuric acid transferred to the first input pipe 21 is atomized and sprayed into the mist phase through the nozzle 22 installed at the end of the first input pipe 21, and the concentrated sulfuric acid is also dispersed throughout the entire region inside the reactor 10. do.

As such, the concentrated sulfuric acid and the electric furnace dust are uniformly dispersed in a small particle state by vibrating structures of the nozzle 22 and the vibration plate 40, respectively, and the reaction region occurs in all regions in the reactor 10, compared to the conventional method. The reaction efficiency can be raised.

On the other hand, in order to double the reaction efficiency of the dust and concentrated sulfuric acid, the rotary disk 50 provided with a mill 52 in the lower portion of the reactor 10 may be installed.

As shown in FIG. 3, the turntable 50 has a circular plate shape, and a cylindrical mill 52 is provided at one side of the upper surface of the turntable 50, and a lower end of the mill 52 is the turntable 50. It is in contact with the upper surface of.

As shown in FIGS. 1 and 3, the lower part of the central shaft of the turntable 50 is connected to the rotation driving means 54 connected to the motor M, and is rotated from the starting point to the center axis by the driving of the motor M. The rotation drive means 54 may be, for example, a worm gear or a belt. In addition, the mill 52 is also rotatably installed by the motor (M).

At this time, the outer surface of the mill 52 is provided with a plurality of protrusions 53 protruding in the longitudinal direction, it is preferable that the uneven portion 51 is formed on the upper surface of the rotating plate (50). The concave-convex portion 51 may be a combination of a radial and a plurality of concentric shapes, as shown in FIG. 3, may be a grid shape, although not shown, the shape is not limited. In addition, the protrusions 53 formed on the outer surface of the mill 52 may also be embossed in the form of dots, and the shape is not limited.

The rotary plate 50 including the mill 52 receives the unreacted electric dust powder and the concentrated sulfuric acid fine particles in the process of falling inside the reactor 10 to perform the secondary reaction, and the protrusions 53 and the uneven portion. (51) can increase the reaction efficiency by allowing the dust and concentrated sulfuric acid mixture to fall between the rotary disk 50 and the mill 52 to be introduced into the rotary disk 50, the mixture is pressurized and stirred, and the reaction product is continuously It is possible to manufacture with.

Hereinafter, an Example is given and this invention is demonstrated in detail.

EXAMPLE

240 kg of reciprocating movement per minute and 3 kg of electric furnace dust (EAFD) with a zinc content of 30% by weight were introduced into the diaphragm 40 having a diameter of 0.5 mm, and the electric dust powder was introduced into the reactor 10 for 30 minutes. During the dropping reaction, 1350 g of concentrated sulfuric acid is sprayed for 30 minutes so that the ratio of 450 g per 1 kg of dust is electrically charged.

In addition, the dust and the concentrated sulfuric acid mixture was dropped to the rotary plate 50 equipped with a mill 52, and stirred and reacted once more to recover 4 kg of the reactant. Here 350g was discharged as steam generated during the reaction of dust and concentrated sulfuric acid with electricity.

The recovered reactants were stirred for 60 minutes in 12 liters of water at 80 ° C, and the dissolved sample was filtered to recover 3 liters of zinc sulfate solution. The solution was added by stirring 2 liters of water to the remaining cake, and the total solution was collected. Recovered.

The solution was concentrated by heating to recover 2.2 kg of zinc sulfate monohydrate (ZnSO ₄ H ₂ O), which corresponds to 95% of the dust content of zinc.

Although the above description has been made based on the limited structure and the limited embodiments of the accompanying drawings, the present invention is not limited to the illustrated description, and those skilled in the art can modify the design as needed by those skilled in the art. It should be noted that changes are included within the following claims.

1 is a schematic view showing a melting apparatus of an electric furnace dust according to an embodiment of the present invention.

Figure 2 is a partial perspective view showing the structure of the vibration plate of the melting apparatus of the electric furnace dust according to an embodiment of the present invention.

Figure 3 is a partial perspective view showing the structure of the rotary disk of the melting apparatus of the electric furnace dust according to an embodiment of the present invention.

<Explanation of the Codes in Drawings>

10 ... reactor 11 ... discharge line

12 ... intake pump

20 ... Hopper 21 ... 1st input tube

22 ... nozzle

30 2nd Hopper 31 ...

32 ... Second Input Tube

40 ... vibration plate 41 ... hole

42 ... link bar 43 ... cam

50 ... turntable 51 ... irregularities

52 ... mill 53 ... turning

54. Rotary drive means

60 ... outlet 61 ... reservoir

Claims (7)

A reactor 10 having a gas discharge pipe 11 at an upper end thereof, and a discharge means 60 connected to a storage tank 61 at a lower end thereof; A first injection pipe 21 installed above the reactor 10 and provided with a nozzle 22 to spray concentrated sulfuric acid into a mist; A second injection pipe 32 installed above the reactor 10 to inject dust into electricity; Zinc sulfate from the electric furnace dust is installed on the reactor (10) to accommodate the dust in the electric furnace and a plurality of holes (41) formed on the bottom surface consisting of a vibration plate 40 capable of reciprocating in the horizontal direction Manufacturing equipment. The method according to claim 1, A cylindrical mill 52, which is rotated by the rotary driving means 54 and pressurized and rotates in contact with one side of the upper surface of the reactor 10, is provided with a rotary disk 50 for stirring and stirring the dust mixture with concentrated sulfuric acid. Apparatus for producing zinc sulfate from electric dust, characterized in that. The method according to claim 2, Apparatus for producing zinc sulfate from an electric dust, characterized in that the concave-convex portion (51) is formed on the upper surface of the rotary disk (50). The method according to claim 2, Apparatus for producing zinc sulfate from electric dust, characterized in that a plurality of protrusions (53) formed on the outer surface of the mill (52). The method according to claim 1, The link bar 42 is connected to one side of the vibration plate 40, and the other side of the link bar 42 is connected to an eccentric position in the center of the cam 43, and thus, the vibration plate 40 is rotated by the cam 43. An apparatus for producing zinc sulfate from electric furnace dust, wherein the reciprocating flow is enabled. In the electric dust dissolution method in concentrated sulfuric acid, The concentrated sulfuric acid is sprayed into the mist through a nozzle installed in the upper part of the reactor, and the dust is discharged through the hole by introducing dust into the vibrating plate in which the reciprocating flow in the horizontal direction from the upper part of the reactor and the plurality of holes are formed at the bottom. A method for producing zinc sulfate from an electric dust, characterized in that the powder and the sprayed concentrated sulfuric acid are mixed and reacted. The method according to claim 6, And collecting the mixture of the dust and the concentrated sulfuric acid in a rotary disk in which the mill is formed so that the mixture is secondaryly reacted between the mill and the rotary disk.

Images