KR960002914B1 - Making method and apparatus of zinc-powder forom iron & steel casting dust - Google Patents

Abstract

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Description

Method for producing zincification from steelmaking and its apparatus

1 is a schematic diagram of a schematic diagram of a first stage processing apparatus of an apparatus for implementing the method of the present invention.

2 is a schematic schematic diagram of a second stage processing apparatus.

* Explanation of symbols for main parts of the drawings

1: 1st stage processing apparatus 2: 2nd stage processing apparatus

3: rotary kiln as first stage furnace 4,7: conduit

5: washing tower as first stage recovery device 6: rotary kiln as second stage heating furnace

8: second stage recovery device

The present invention relates to a method and apparatus for continuously producing galvanization from steel grinding in steelworks.

In steel mills that use steel blast furnaces, flat furnaces, and electric furnaces to produce steel, a large amount of steelmaking is generated from the blast furnace, the furnace and the electric furnace.

This steelmaking dust has been dissipated to the atmosphere in the past, but in recent years, due to the strengthening of the air pollution prevention administration, installation of dust collectors has become mandatory, and now most of them have been recovered without being dissipated into the atmosphere.

The recovered steelmaking dust is difficult to handle because of its fine particles, and various metals are mostly contained as oxides, each containing metal is of low quality, and it is a by-product of steel making. It was not taken care of as a conventional industrial source because it could not be obtained.

In recent years, however, there has been a risk of secondary pollution caused by the above-mentioned properties of steelmaking and heavy metals, and it cannot be disposed of as it is.

However, in view of the fact that a large amount of zinc is contained during steelmaking and can be controlled as a zinc resource, the present inventors have recovered powdered zinc oxide mainly made of oxides of zinc, lead and cadmium from steelmaking lead. It has been commercialized since 1966, and now 90% of the steel production from electric furnaces in Japan has been effectively processed.

In this way, production of electrolytic zinc, distilled zinc, and zincification using crude zinc oxide produced from steelmaking zinc has been performed by various companies.

Conventionally, the manufacturing method of galvanization includes the French method produced from zinc now, the American method produced from zinc ore or zinc dross, and the method produced from steelmaking using an electric furnace in recent years. There is a method of producing zincification from steelmaking lead using the proposed three-stage rotary furnace (Japanese Patent Publication No. 50-33994).

However, since either method has a lot of complexity and energy consumption and is a problem of economics, the present inventors and the like intend to more effectively produce zinc from steelmaking.

In the zinc refining industry, whether it is an excellent method or not, whether it can be carried out on an industrial scale depends largely on profitability. In terms of technical aspects, the continuous production of zinc from steelmaking requires several treatment processes and a large amount of heating energy. How can a simple process be used and how can energy be used less? Becomes an important factor.

From this point of view, the conventional method for producing zincification or the method described in Japanese Patent Laid-Open No. 50-33994 described above can obtain zincation only after three stages of treatment using three recovery furnaces. Since a large amount of heating energy is required, a simple process is also desired to emerge the method of using less energy.

In particular, the emergence of a new manufacturing method is urgently desired in the confusion of the current zinc market.

In the method described in Japanese Patent Laid-Open No. 50-33994, from the above-mentioned point of view, the object to be treated is limited to a furnace with a high zinc content and a steelmaking furnace from an electric furnace, and from a blast furnace having a low zinc content and a low content rate. Was not the subject of steelmaking.

However, as mentioned above, when steelmaking smoke is disposed of as it is, it is difficult to secure a place for disposal and depending on the disposal method, it may be a source of secondary and tertiary pollution. Also, there has been a demand for the emergence of a method capable of efficiently and efficiently recovering zinc.

It is, therefore, an object of the present invention to provide a method and apparatus for producing zinc oxide from steel making with extremely simple processes and using less energy in a much simpler process than conventionally known methods to meet such demands. have.

Further, another object of the present invention is to achieve zinc oxide of higher purity than the conventional method while achieving the above economical purpose.

According to the above-described method, a method for producing zinc from steelmaking zinc is first performed by heating the steelmaking zinc produced during steelmaking to 800 ° C-1100 ° C without adding an additive, and mainly during steelmaking rolling. Selective volatilization of lead, cadmium, and chlorine to produce quenching quenching in which zinc and iron remain as zinc oxide and iron oxide, and then heating the quenching quenching with a reducing agent coke to 900 ° C-1100 ° C Then, zinc oxide in the quenching is once reduced and selectively volatilized as metal zinc vapor, and the metal zinc vapor is oxidized in an oxidizing atmosphere to produce zincation.

In this case, the heat generated when the metal zinc vapor is reclaimed is effectively utilized.

In addition, the apparatus for producing galvanized steel from the steelmaking dust of the present invention includes a first stage heating furnace in which steelmaking dust is introduced from one end, and the steelmaking zinc introduced is heated and burned in the inside, and is transferred to the other end to be discharged as calcination extinction, and the first A first stage treatment device having a first stage recovery device connected to a first stage furnace and collecting volatilized volatilities from the steelmaking dust during the above-mentioned process, together with the quench extinguishing discharged from the first stage furnace Reduction coke input from one end and the second stage rotary furnace where the mixed quenching and coke are heated inside and transported to the other end and discharged as combustion slag, and the second stage heating furnace. Zinc produced by the refining of metal zinc vapor volatilized from the quenching furnace under the above-mentioned reducing atmosphere in the furnace by air flowing through the furnace The second stage of collecting takes place from the recovery apparatus.

Steelmaking rolling which is the object of processing in the above-described method and apparatus is both a furnace, an electric furnace, and a blast furnace. The steelmaking dust generated from the furnace and electric furnace is slightly different due to the difference in the quality of steel or the steelmaking method of the raw materials, but the content and standard quality of the steel are roughly as shown in Table-1, and the amount is produced per ton of crude steel produced. 1-2%.

TABLE 1

At present, for the convenience of transportation, steelmaking powder is granulated pellets of 2-5mm diameter in the source plant and contains 4-7% water. In addition, steelmaking smoke generated in the blast furnace is not used as a raw material for the galvanizing bath because of the low zinc content in the present situation, but as described below, the high-efficiency galvanizing bath according to the present invention is sufficient for the method of the present invention. Can be treated. Standard grades of steel grinding in blast furnaces are as shown in Table-2.

TABLE 2

In the present invention, the above-mentioned steelmaking additives are first heated to 800 ° C.-1100 ° C. at normal pressure without adding an additive, and then heated under the temperature, and the aeration time is about 30 minutes to 90 minutes.

The steelmaking is carried out while the steelmaking roll is fed from one end of the first stage heating furnace, and the steelmaking roll is transferred to the other end in the first stage heating furnace. As this 1st stage heating furnace and the 2nd stage heating furnace mentioned later, a rotary furnace (rotary kiln) is preferable, and the rotary furnace which inclines slightly in particular is preferable.

By using such a rotary furnace, the steelmaking smoke added from one end is naturally transferred to the other end according to the rotation of the furnace.

That is, generally, a batch furnace is used, but continuous processing is possible by the rotary furnace as described above.

In this process, lead, cadmium, and chlorine are selectively volatilized in steelmaking, and part of lead chloride, cadmium oxide, cadmium chloride, and salt (NaCl) is recovered and connected to the first stage furnace. Collected by the device and recovered.

The zinc and iron contained in the steelmaking rolling remain without volatilization, and are extracted from the other end of the first stage heating furnace as a quenching extinction to become a raw material for the second stage treatment described later.

Lead, cadmium, and chlorine are selectively volatilized and zinc and iron remain in the volatilization in the above-mentioned air chambers for the following reasons. In other words, most of the chlorine in steelmaking is remaining in the form of NaCl without making other chlorides, and it is proved by the present inventors that PbO and CdO contained as part of NaCl and oxide in steelmaking Represents a reaction to generate chloride, which is believed to promote the volatilization of lead, cadmium and chlorine.

This was confirmed by the results of experiments that if steelmaking lead of raw material was turned on in advance and NaCl was removed, lead, cadmium, and chlorine would be difficult to volatilize from NaCl-free samples.

The reaction for generating the above-described chloride is expressed as follows for PbO, CdO, ZnO, Fe ₂ O ₃ .

ΔG ° 1, ΔG ° 2, ΔG ° 3, and ΔG ° 4 indicate standard free energy changes in each reaction.

The standard free energy change (Cal) at each temperature is shown in Table-3.

TABLE 3

In the above formulas (1), (2), (3) and (4), the smaller the value of ΔG ° in Table-3, the easier the reaction proceeds to the right, so that CdO is most likely to be chlorinated, and PbO is better than that. It is hard to be chlorinated slightly, and ZnO and Fe ₂ O ₃ are much harder to be chlorinated than PdO and CdO.

Therefore, in the above-mentioned air temperature at the above-described temperature, the reactions of the above formulas (1) and (2) occur actively, but the reactions of the formulas (3) and (4) hardly occur.

The reaction of formula (1) and (2) is thought to play a role of promoting volatilization of Pb, Cd, and Cl components in steelmaking, and is realistically quenched as shown in the specific data in the following examples. There are few components of Pb, Cd, and Cl, and a large amount of Zn and Fe components remain.

In this way, the quenching quenched by the first stage treatment is rarely contained due to the removal of lead, cadmium, and chlorine components, and is taken out as the content of the remaining zinc and iron is increased and sent to the second stage treatment.

In the second stage treatment, coke is mixed into the above-described quenching as a reducing agent.

The mixing ratio of coke is suitably about 30% by weight.

The mixture is introduced into a second stage furnace and heated to 900 ° C.-1100 ° C. and maintained at that temperature.

Holding time is about 30-90 minutes is appropriate.

In this heating, zinc oxide in the quenching is reduced by coke and selectively volatilized as metal zinc vapor due to the difference in the metal vapor pressure from iron.

It is then immediately reoxidized in an oxidizing atmosphere, for example by means of suitable air drawn into the furnace at the same time, to produce pure zinc zincification.

At this time, the heat generated when the metal zinc vapor is reoxidized is also effectively used. The zincation is collected by a second stage recovery device connected to a second stage heating furnace to obtain a target zincation.

Since the obtained zincation is selectively separated from iron in the first stage treatment with iron, cadmium, and chlorine separated from iron by the difference in the metal vapor pressure in the second stage treatment, the purity is very high and according to the American law. It exceeds the zinc standard to be produced and is comparable to the French zinc method.

The energy required in the method of the present invention is mainly divided into those consumed for heating steelmaking and coke to a predetermined temperature and those consumed for reduction of zinc oxide.

In the latter case, however, the zinc vapor and carbon monoxide produced are oxidized into zinc and carbon dioxide by secondary air, and thus heat up again. As a result, an excessive amount of energy is generated when coke is burned into carbon dioxide. .

This energy reaches 1,160 kcal per kilogram of zinc produced, which can be effectively recovered and used to heat the primary air for charges or ignition burners, which can drastically reduce energy consumption.

Part of the coke is also consumed in the reduction of the iron oxide, but the reduction of the iron oxide is very gentle as compared to the case of zinc which immediately becomes a vapor when it is reduced to the metal and disappears out of the reaction system.

In the conventional method, the heat recovery is performed three times in order to remove impurities in the crude zinc oxide produced by the heating of the first stage by washing with water and the second stage of heating, and then return to the third stage of zinc production process. Coke mixing process is also required twice.

In the first step of coarse zinc oxide recovery, the volatilization of chlorine is remarkable, so that effective heat recovery is difficult, and the heat of combustion cannot be effectively used as compared to the use of twice as much coke as the present method.

In the method of the present invention, on the other hand, in the first stage treatment, lead, cadmium, chlorine component, zinc and iron are separated into the quenching quench remaining, and in the second stage treatment, the zinc component is separated from the quenching quenching. Therefore, the process ends as a two-step process and the whole process is simplified.

Moreover, coke mixing process is good only once.

In addition, since the furnace has two stages and the regeneration of metal zinc vapor and the heating of carbon monoxide can be used, the energy used to produce zinc is about 2/3 or less than the conventional three-stage method described above. Is reduced.

In addition, the combustion slag taken out from the second stage heating furnace in the second stage treatment can be used as a raw material of sintered ore in blast furnace injection because the iron content is obtained in the form of significantly increased iron content.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 and 2 show schematic machine cylinders of an apparatus for implementing the method of the present invention.

In FIG. 1, (1) of FIG. 1 shows the whole first stage processing apparatus, and (2) of FIG. 2 shows the whole second stage processing apparatus.

The first stage treatment apparatus 1 includes a rotary kiln 3 as first stage heating and a washing tower 5 as a first stage recovery apparatus connected to the rotary kiln 3 via a conduit 4. Holds.

As heating source of the rotary kiln 3, steaming or kerosene is used, and air is sucked in with this.

The heated air sucked from one end of the rotary kiln 3 passes through the rotary kiln 3, passes through the conduit 4, passes through the washing tower 5, and is exhausted as exhaust.

The second stage treatment apparatus 2 is configured as almost the same apparatus, and the number of second stages connected to the rotary kiln 6 and the rotary kiln 6 via the conduit 7 as the second stage heating furnace is provided. The device 8 is retained.

As a heating source of the rotary kiln 6, distillation or kerosene is used, together with the air being sucked in, and the heated air passes through the second stage recovery device 8 and is then exhausted.

The rotary kilns 3 and 6 are inclined so that the raw material introduction port side 3a and 6a become a position slightly higher than the other end 3b and 6b.

In the rotary kilns (3) and (6), the rotation speed can be adjusted, and the raw materials introduced from the inlet side 3a and 6a are transferred toward the other ends 3b and 6b, but the speed In other words, the residence time in the furnace can be adjusted by the rotation speed.

Using such an apparatus, the zinc production was performed as follows. First, steelmaking lead used as raw material is generated in the electric furnace and its quality is shown in Table-4.

TABLE 4

The steelmaking dust is continuously introduced from the inlet 3a of the rotary kiln 3 without adding an additive, and is heated to 800 ° C-1100 ° C in the furnace while moving the furnace toward the outlet 3b. The rotation speed of the rotary kiln 3 was adjusted so that the burning time of about 60 minutes could be made into temperature. Lead, cadmium, and chlorine volatilized while steelmaking stretched through the furnace, and the volatiles were recovered in the washing tower 5 as lead oxide, lead chloride, cadmium oxide, cadmium chloride, and salt slime.

And the quenching extinguishing which zinc and iron components remain as a non volatile matter was obtained in the discharge port 3b.

The content of each component of the obtained calcination was as shown in Table-5, and lead, cadmium, and chlorine were almost removed.

TABLE 5

Next, the above-described photoquenching is introduced while mixing about 30% by weight of coke from the inlet 6a of the rotary kiln 6, and heating in the furnace to 900 ° C-1100 ° C, and the residence time in the furnace. The rotation speed of the rotary cl 6 was adjusted so that it might be 60 minutes.

During this heating, zinc is volatilized selectively due to the difference of the metal vapor pressure, and zinc zinc is volatilized by volatilized metal zinc vapor from the heated air sucked from the other end, and the resulting zincation is recovered with the second stage together with air. It was sent to the apparatus and recovered as zinc white with high purity of pure white. At this time, the heat generated during the reoxidation of the metal zinc vapor contributed sufficiently to energy saving.

The quenching quenched by the volatilization of the zinc component was discharged from the outlet 6b as a combustion slag. The obtained zinc-containing component was as shown in Table-6, and the thing of high purity as much as the standard of zincization manufactured by the French method was obtained.

TABLE 6

In addition, the components of the residual combustion slag are shown in Table 7, and it can be seen that zinc, lead, and cadmium were volatilized with high efficiency.

TABLE 7

As described above, the combustion slag can be used as a raw material for sintered ore because the iron content is significantly increased.

As described above, according to the method and apparatus for producing zinc from the steel dust of the present invention, the first stage treatment apparatus and coke which volatilizes lead, cadmium, and chlorine by actively utilizing the action of NaCl coexisting during steel grinding. Was used as a reducing agent to obtain high-purity zinc by two-step treatment with the second stage treatment of volatilizing zinc by selectively volatilizing and reoxidizing zinc by using the difference in metal vapor pressure. Can greatly reduce the required energy, greatly reduce the required energy, and can significantly reduce the equipment cost can be economically produced zinc.

Therefore, it is possible to make effective use of steelmaking smoke from the blast furnace, which has not been used at all, as well as steelmaking smoke generated in the furnace and electric furnace. In addition, the obtained zincation is comparable to the standard of the French method zincification, and the effect that a product quality can be improved significantly is also acquired.

Claims (2)

The steelmaking dust produced during steelmaking is heated by heating in the rotary kiln (3) at a temperature of 800 ° C.-1100 ° C. for 30 minutes to 90 minutes without adding any additives, and mainly lead, cadmium, The chlorine is selectively volatilized and recovered by the washing tower (5), and the first step of producing quenching extinguishes remaining of zinc and iron as zinc oxide and iron oxide; After mixing with oaks and heating in a rotary kiln (6) at a temperature of 900 ° C to 1100 ° C for 30 minutes to 90 minutes, the zinc oxide in the above-described quenching furnace is once reduced and selectively volatilized as metal zinc vapor to be separated from iron oxide. The zinc zinc is reoxidized by air flowing through the interior of the rotary kiln 6 to generate zinc, and then the air in the rotary kiln 6 containing the zinc is recovered. After the suction with the 8 zinc from steel making method for producing a yeonjin it characterized in that the second stage consists of a process for collecting only the above-mentioned zinc white. The inlet side 3a is inclined so as to be a slightly higher position than the other end 3b, and steelmaking injecting is introduced from the inleting side 3a, and the introduced steelmaking injecting is performed at a temperature of 800 ° C to 1100 ° C inside. It is connected to the rotary kiln (3) through the rotary kiln (3) through the conduit (4) and the rotary kiln (3), which is heated and charged, and is transported to the other end (3b) and discharged as quenching extinguishing. The first stage treatment apparatus 1 having a first stage recovery device 5 for collecting volatiles volatilized from steelmaking smoke, and the inlet side 6a are inclined so as to be slightly higher than the other end 6b. Reducing coke is introduced from the inlet side 6a together with the co-quenching discharged from the rotary kiln 3, and the above-mentioned co-quenching is carried out inside the coke with a temperature of 900 ° C to 1100 ° C. Heated to the other end (6b) is connected to the rotary kiln (6) discharged as a matting material and the above-mentioned rotary kiln (6) via a conduit (7), and the metal zinc vapor volatilized from the quenching under reduced atmosphere The zinc in the air in the rotary kiln 6 is aspirated by aspirating the air in the rotary kiln 6 containing zinc oxide generated by reoxidation by the air flowing inside the rotary kiln 6. And a second stage treatment apparatus (1) having a second stage recovery apparatus (8) for collecting the galvanizing apparatus from steelmaking lead.

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