JPH08188837A - Lead splash condenser equipment - Google Patents

Abstract

PURPOSE: To improve the condenser efficiency of an equipment by allowing a reducing furnace flue gas contg. zinc vapor to contact with the splashed molten lead and placing an impingement plate(s) in a gas space where the molten lead droplets are splashed within a lead splash condenser for dissolving zinc vapor in molten lead. CONSTITUTION: In this equipment, at least one impingement plate is placed in a space where molten lead droplets are splashed, within the condenser, preferably at a position between lead splash rotors, at the position of both the upstream and downstream side ends of the condenser or a position above the agitating blades of any of the splash rotors and also, the shape of each of the impingement plates is platelike, punched-platelike or suspended-chainlike. Thus, the molten lead droplets are positively allowed to impinge on the impingement plates to subject them to secondary splashing and thereby, the lead droplets are more finely divided to increase their specific surface area and to enhance the splashing efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead splash condenser facility for recovering zinc vapor from a reducing furnace exhaust gas containing the zinc vapor by dissolving the zinc vapor in molten lead.

[0002]

2. Description of the Related Art The ISP method is a typical dry zinc smelting method for simultaneously recovering lead and zinc from a zinc concentrate containing lead. In this ISP method, the zinc raw material is reduced and melted in a reducing furnace, and zinc and lead are volatilized, and the lead and zinc are recovered together with the exhaust gas in a recovery process in a subsequent process. Then, in this recovery step, a lead splash capacitor using molten lead as an absorbent is used. As shown in the schematic plan view of FIG. 5, the lead splash condenser includes a condenser body 3 having one end connected to the outlet of the reduction furnace 1 and a smoke exhaust passage 2 provided at the other end, a cooling gutter 4, and a cooling gutter 4. A flux furnace 5 for adding ammonium chloride to the melt flowing out by overflow, a separation furnace 6 for separating lead and zinc, a heating furnace 11 for keeping the temperature of the recovered zinc constant, and a recovered melt. It is composed of a return furnace 7 for returning to the condenser body 3. Further, the condenser main body 3 is provided with a lead splash rotor 8 in a central portion thereof, a sump 9 having an underflow structure sealed with molten lead on the exhaust gas upstream side of the lead splash rotor 8, and a lead pump 10 provided in the sump 9. Has been.

During the operation of the lead splash condenser, the molten lead is supplied from the sump 9 to the cooling gutter 4 by using the lead pump 10, and the return furnace 7 returns the molten lead to the condenser body 3 to circulate the molten lead. Make up the system. The reduction furnace exhaust gas is introduced into the condenser main body 3 from the outlet of the reduction furnace 1, and the lead splash rotor 8 provided in the condenser main body 3 is used to circulate the molten lead at a temperature lower than the reduction furnace exhaust gas temperature (circulation lead). ) Is splashed, and circulating lead and reducing furnace exhaust gas are brought into contact with each other. Thereby, the zinc vapor in the reducing furnace exhaust gas is cooled and dissolved in the circulating lead. Then, the circulating lead in which zinc is dissolved is cooled in a cooling gutter 4 to precipitate the dissolved zinc in the circulating lead, and then the separation furnace 6 separates the zinc from the circulating lead. After being introduced into a steel plate to a predetermined temperature, it is cast as crude zinc. Then, the circulating lead is returned to the exhaust gas downstream side of the condenser body 3 via the return furnace 7.

In the operation of this lead splash condenser, it is extremely important to maintain good efficiency of transferring zinc vapor in the exhaust gas of the reducing furnace into circulating lead, that is, condenser efficiency. Factors that affect the condenser efficiency include various conditions of the reducing furnace exhaust gas that cause reoxidation of zinc vapor in the reducing furnace exhaust gas, that is, (a) temperature and (b), which are chemical factors mainly including chemical reactions. CO ₂ / CO and (c) contents of zinc vapor, H ₂ O, dust, etc. may be mentioned, while mechanical factors are (d) a lead splash rotor for efficiently contacting the reducing furnace exhaust gas and circulating lead. The situation of lead splash (hereinafter referred to as splash efficiency) and (e) the arrangement of a current plate for efficiently absorbing zinc vapor in the exhaust gas of the reducing furnace by the splashed lead particles can be mentioned.

Among these factors, the splash efficiency of (d) will be described below. In FIG. 5, the lead splash rotors 8 are usually arranged in parallel in two rows from the upstream side of the exhaust gas, and four rows in total are arranged. In order to increase the splash efficiency, the shape and rotation of the stirring blades of the lead splash rotor 8 are set. The number and the depth of keeping the stirring blades of the lead splash rotor 8 in the circulating lead are adjusted individually for each smelter to optimize it. For example, if the evaluation of the splash efficiency is performed by directly setting the index to the condenser efficiency, the influence of these chemical factors is greatly affected by the influence of the chemical factors that affect the condenser efficiency as described above and the evaluation of the splash efficiency is erroneous. In order to prevent the reduction furnace exhaust gas as much as possible, an index has been placed on the cooling efficiency of the reduction furnace exhaust gas, that is, the temperature difference between the inlet and outlet of the condenser body. This is because the mass transfer of zinc vapor in the reducing exhaust gas to the circulating lead and the heat transfer of the heat of the reducing furnace exhaust gas to the circulating lead both proceed at the interface between the splashed molten lead particles and the exhaust gas. Therefore, the mass transfer efficiency and the heat transfer efficiency have the same behavior, and therefore, the higher the cooling efficiency of the reducing furnace exhaust gas, the higher the condenser efficiency. However, although this evaluation method can exclude the effects of the above-mentioned chemical factors to some extent, the thermal effects such as heat generation due to the re-oxidation reaction of zinc vapor caused by these chemical factors can never be ignored. No
Therefore, even in this evaluation method, the accuracy is never high.

Further, the arrangement of the current plate (e) will be described. In FIG. 5, the straightening vanes rectify the circulating lead and the exhaust gas from the reducing furnace satisfactorily.
b) are installed alternately, and the structure is such that the condenser ceiling and the furnace bottom are partitioned by one plate, and the rectifying plate is installed in the condenser so as to be perpendicular to the flow of the reducing furnace exhaust gas. The opening of the current plate 12a is
And the side wall of the condenser body 3 and the rectifying plate 12
The opening b is formed in the center of the current plate 12b. In this way, the purpose of dividing the condenser into several reaction tanks by the straightening plate is to reduce the zinc vapor concentration of the reducing furnace exhaust gas and the zinc concentration of circulating lead in each reaction zone in stages from the condenser inlet to the outlet. That is, it is intended to efficiently absorb the zinc vapor of the reducing furnace exhaust gas into the circulating lead by carrying out a countercurrent multi-stage continuous tank type reaction of the reducing furnace exhaust gas and the circulating lead.
As described above, various efforts have been made to increase the condenser efficiency, but it has not been sufficient, and a method for further increasing the condenser efficiency has been desired.

[0007]

SUMMARY OF THE INVENTION In view of the situation as described above, the present invention provides a lead splash capacitor facility capable of increasing the capacitor efficiency,
The purpose is to increase the splash efficiency by the lead splash rotor of (d) above.

[0008]

Means for Solving the Problems As a result of various studies to achieve the above object, the present inventor has achieved the above object by miniaturizing lead particles scattered by a lead splash rotor and increasing the surface area thereof. The present inventors have obtained the finding that they can, and have reached the present invention. That is, the lead splash condenser equipment of the present invention is a lead splash condenser equipment in which a reducing furnace exhaust gas containing zinc vapor is brought into contact with scattered lead particles of a molten metal to dissolve the zinc vapor in molten lead. It is characterized in that a lead collision plate is provided in the gas space in which is scattered. The location of the lead collision plate is preferably between the lead splash rotors, both upstream and downstream sides of the condenser, and above the stirring blades of the lead splash rotor. The lead collision plate may have a plate shape, a punch plate shape, a hanging chain shape, or the like. Furthermore, the lead collision plate is not limited to one, and a plurality of lead collision plates may be provided.

[0009]

In the present invention, the reason why the lead collision plate is provided in the gas space in which the molten lead particles are scattered by the lead splash rotor is that the lead particles are positively applied to the lead collision plate to cause secondary scattering, This is because the particles can be made finer to increase the surface area thereof, that is, the splash efficiency can be increased. Since the absorption reaction of zinc vapor in the reducing furnace exhaust gas into the circulating lead proceeds mainly at the interface between the lead particles scattered by the lead splash rotor and the reducing furnace exhaust gas as described above, the contact area between the two is The larger the surface area of the lead particles, the better the efficiency of the absorption reaction, that is, the condenser efficiency, and the better the cooling efficiency of the reducing furnace exhaust gas. That is, when the lead collision plate of the present invention is used, the lead particles in the gas space of the condenser are miniaturized and the surface area thereof is increased, whereby the condenser efficiency can be increased. As described above, the lead collision plate of the present invention is intended to miniaturize the scattered lead particles by collision.Therefore, regarding the shape of the lead collision plate, if the scattered lead particles collide and are miniaturized and scattered again. Any shape may be used, for example, a plate-shaped one, a punch plate-shaped one, or hanging a chain can obtain the effect of the present invention.

The location of the lead collision plate is not particularly limited as long as it is basically a gas space in which lead particles generated by the lead splash rotor are scattered, but the distribution of lead particles due to collision is not limited. It is not desirable to install it in a place that creates a sparse gas space. This is because, for example, when a lead collision plate is installed in parallel with the capacitor side wall between the capacitor side wall and the adjacent lead splash rotor, this lead collision plate becomes an obstacle for lead particle scattering, and this and the capacitor side wall This is because the distribution of lead particles in the gas space becomes sparse, so that efficient contact between the reducing furnace exhaust gas and lead particles is hindered, and the effect of the present invention cannot be expected. Therefore, (a) normally between eight lead splash rotors arranged in the condenser, (b) both upstream and downstream ends of the condenser, and (c) the stirring blades of the lead splash rotor as shown in the embodiment. It is most effective to install it on the top.

It can be considered that the rectifying plate provided in the lead splash condenser facility also plays a role of the lead collision plate as well as the side wall and ceiling of the condenser, but as described above (prior art), The lead collision plate of the invention has a different purpose and structure. Since the current plate is intended to divide the condenser into several reaction tanks, it is required to install it vertically to the flow of the reduction furnace exhaust gas and to have an integrated structure that partitions the condenser ceiling to the furnace bottom. However, as explained above, the lead collision plate of the present invention is not intended to be immersed in the circulating lead because it is intended to refine the lead particles, and it is further necessary to install it vertically to the flow of the reducing furnace exhaust gas. Absent.

[0012]

[Examples] In the examples and conventional examples described below, only the coke powder was burned to produce a reducing furnace exhaust gas containing no zinc vapor, which was introduced into a lead splash condenser, and the reducing furnace was installed with or without a lead collision plate. The method of comparing the difference in cooling efficiency due to circulating lead of exhaust gas was adopted. Here, the effect of the present invention is evaluated by the cooling efficiency of the reducing furnace exhaust gas that does not contain zinc vapor, as described above (prior art), except for the error accompanying the reoxidation of zinc vapor, the evaluation accuracy of the splash efficiency. This is to raise. Also, the splash efficiency that affects the condenser efficiency can be evaluated by capturing the cooling efficiency of the reduction furnace exhaust gas. That is, if the cooling efficiency of the reduction furnace exhaust gas is increased by installing the lead collision plate, it can be determined that the condenser efficiency is also increased. The cooling efficiency of the reduction furnace exhaust gas was evaluated by the following method. That is, since the lead splash condenser can be regarded as a countercurrent heat exchanger of the reducing furnace exhaust gas and the circulating lead, the cooling heat quantity Q of the reducing furnace exhaust gas can be generally expressed by Equation 1, and the cooling efficiency is
It can be expressed by the product kf of the heat transmission coefficient k and the heat exchange area f in the equation 1. That is, in the evaluation of cooling efficiency, kf
It can be said that the larger is, the higher the cooling efficiency is.

[0013]

[Equation 1]

However, Q: amount of heat of cooling exhaust gas (kcal / h) k: heat transmission coefficient (kcal / m ² · h · ° C) f: heat exchange area (m ² ) ΔT ₁ : (condenser inlet exhaust gas temperature) -(Condenser outlet temperature of circulating lead) (° C) ΔT ₂ : (Condenser outlet exhaust gas temperature)-(Condenser inlet temperature of circulating lead) (° C)

Therefore, as shown in FIG. 5, the circulating lead holding amount 2 having the inner dimensions of length 10 m, width 2 m and height 0.58 m is 2
A 5.2t condenser is used, and a front view is shown in FIG.
And as shown in FIG. 7 as a plan view, the blade mounting angles are 55 ° and 60 ° with respect to the horizontal plane.
Eight lead splash rotors 8 (outer diameter 240 mm) with stirrer blades alternating with each other (outer diameter 1600 mm between the two rotors in each reaction tank) were used, and hot air from a reduction furnace containing no zinc vapor was used. (Exhaust gas from burning coke powder 520 Nm ³ / h, CO 7%, CO ₂ 45%)
Through the condenser, and under the conditions shown in Table 1, the exhaust gas temperature at the condenser inlet, the exhaust gas temperature at the condenser outlet, the temperature of molten lead entering the condenser, and the temperature of molten lead discharged from the condenser were measured. The cooling efficiency was calculated by Equation 1. The rotational speed of the lead splash rotor was 250 to 400 rpm, and the dipping rate was 67%.

[0016]

[Table 1]

[0017]

Example 1 As shown in the schematic plan view of the lead splash condenser body of FIG. 1, lead collision plates were installed at four condenser gas spaces between two lead splash rotors in each reaction tank. The lead collision plate has a width of 300 mm and a length of 40.
An iron plate having a thickness of 0 m and a thickness of 10 mm was hung so that the width direction was parallel to the length direction of the capacitor and the length direction was perpendicular.

[0018]

Example 2 The lead collision plate of FIG. 1 was removed, and the lead collision plate was attached above the stirring blade of the lead splash rotor of FIG. FIG. 2 shows a schematic front view of the lead splash rotor having the lead collision plate attached thereto, and FIG. 3 shows a sectional view taken along the line aa in FIG. In FIG. 2 and FIG. 3, the lead collision plate was attached with four iron plates having a width of 50 mm, a length of 150 mm and a thickness of 10 mm, forming an angle of 90 ° with the adjacent plates and inclined from the horizontal.

[0019]

Conventional Example The same procedure as in Example 2 was carried out except that the lead collision plate was not attached. Table 2 shows the above results. From Table 2, a graph showing the relationship between the cooling efficiency and the rotation speed is shown in FIG.

[0020]

[Table 2]

Both when the lead collision plate was installed in the gas space of the condenser and when it was installed in the lead splash rotor, the cooling efficiency of the reduction furnace exhaust gas was higher than that when the lead collision plate was not installed. Was given.

[0022]

According to the method of the present invention, in a lead splash condenser facility for recovering zinc vapor as molten zinc from a reducing furnace exhaust gas containing zinc vapor, lead collision occurs in the gas space in the condenser where lead splash is scattered. By installing one or more plates, the cooling efficiency of the reducing furnace exhaust gas by circulating lead can be increased, that is, the condenser efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a lead splash capacitor according to an embodiment of the present invention.

FIG. 2 is a schematic front view of a lead splash rotor having a lead collision plate according to another embodiment of the present invention.

3 shows a cross-sectional view taken along the line aa in FIG.

FIG. 4 is a graph showing the relationship between the cooling efficiency and the rotational speed obtained in Example 1, Example 2 and the conventional example.

FIG. 5 is a diagram illustrating the operation of a conventional lead splash capacitor.

FIG. 6 is a front view showing an impeller of a lead splash rotor used in Examples 1, 2 and a conventional example.

FIG. 7 is a plan view similar to FIG.

[Explanation of symbols]

 1 Reduction furnace 2 Flue gas duct 3 Condenser body 4 Cooling gutter 5 Flux furnace 6 Separation furnace 7 Return furnace 8 Lead splash rotor 9 Sump 10 Lead pump 11 Heating furnace

Claims (3)

[Claims] 1. In a lead splash condenser facility for bringing a reducing furnace exhaust gas containing zinc vapor into contact with the dispersed molten lead particles to dissolve the zinc vapor in the molten lead, the lead particles are dispersed in a gas space. Lead splash condenser equipment characterized by providing at least one lead collision plate. 2. The lead splash condenser facility according to claim 1, wherein the lead collision plate has a plate shape, a punch plate shape, or a hanging chain shape. 3. The lead splash condenser equipment according to claim 1, wherein the lead collision plate is provided between the lead splash rotors, both upstream and downstream sides of the condenser, or above the stirring blades of the lead splash rotor.