KR20100087603A - Continuous process for preparing fine particulate zinc oxide, and the apparatus therefor - Google Patents

Abstract

PURPOSE: A method and an apparatus for continuous preparation of fine particulate zinc oxide are provided to maintain uniform temperature in a vaporizer by compensating the lock of melt resulting from vaporization. CONSTITUTION: A method for continuous preparation of fine particulate zinc oxide comprises the steps of: measuring the amount of molten zinc in a vaporizer(120) using a melt level gauge(12), transmitting the measured level to a controller(11) so that the controller compensates the amount of molten metal reduced according to vaporization by supplying molten metal from a melting furnace(110) and supplies zinc ingot(21) through a hopper(20) into the melting furnace by the reduced amount of molten zinc in the melting furnace, continuously heating the melt with an electric heater method, and producing zinc oxide through oxide reaction of the vaporized zinc discharged through an outlet.

Description

Continuous production method of particulate zinc oxide, and apparatus therefor {CONTINUOUS PROCESS FOR PREPARING FINE PARTICULATE ZINC OXIDE, AND THE APPARATUS THEREFOR}

The present invention relates to a continuous production method of zinc oxide and an apparatus thereof. More specifically, in the method of producing zinc oxide by oxidizing gaseous zinc obtained by melting metal zinc by evaporating (vaporizing) molten zinc with oxygen / air to obtain zinc oxide, and cooling it,

The raw material (zinc) is automatically transferred to the melting furnace through the raw material (zinc) injector commanded from the controller, and the molten zinc in the melting furnace flows over the melting furnace outlet in accordance with the input of the raw material (zinc), and is introduced into the evaporation furnace. Molten zinc is evaporated in the evaporation furnace, and the air / oxygen inlet formed in part of the transfer line during the transfer to the fixing tank reacts with the air / oxygen and gaseous zinc introduced from to form zinc oxide, and the fixing tank and cycling A method of manufacturing zinc oxide, a finished product, through a tank, in which the molten zinc is evaporated and discharged from the evaporation furnace, and the amount of remaining zinc is continuously measured and recognized by the melt level meter, and the controller judges to input raw materials continuously. The present invention relates to an apparatus and a method for continuously producing zinc oxide.

Zinc oxide (ZnO) is widely used in vulcanization accelerators, paints, printing inks, glazes, catalysts, cosmetics such as sun creams, catalysts for manufacturing pharmaceuticals, pigments, batteries, and semiconductor materials.

Conventionally, the method of producing fine zinc oxide is roughly classified into a wet method and a dry method, and a dry method is adopted for mass production. As such a dry method, a French method which is an indirect method and an American method which is a direct method are known. The American law, which is a direct corporation, has a disadvantage in that it contains a large amount of impurities by adding a reducing agent such as coke and coal to zinc ore, heating and reducing it at high temperature to vaporize it, and obtaining zinc oxide by oxidation in the air. On the other hand, the French method produces a high quality product by heating zinc to 1100-1300 ° C. to vaporize zinc and reacting the vaporized zinc with oxygen or air to obtain zinc oxide.

In addition, the production of zinc oxide by the French method consists of the melting of raw materials, the evaporation of molten raw materials, the reaction of evaporated zinc with oxygen, the nucleation, and the cooling and collection after oxidation.

French law is suitable for mass production of zinc oxide, but evaporation, reaction type is batch or semi-continuous type, and air is introduced into the evaporation furnace to form an oxide film due to oxidation reaction on the surface and vapor phase due to reduction of evaporation area. Lower emissions of zinc and lower zinc oxide production occur. And in order to heat up the low temperature of the molten raw material into the evaporator quickly to the evaporation temperature to supply the heat excessively using a burner of oil or gas as a result, the production efficiency compared to the supply heat is low. In addition, in a batch or semi-continuous unit, a low temperature molten raw material is added and the temperature is raised to generate heterogeneous primary particles by the reaction in the temperature range between the temperature at which evaporation starts and the temperature at which the reaction is active. Problems such as the production of other forms of primary particles, such as acicular zinc oxide, due to the splashing of the melt droplets accordingly. These different types of primary particles cause degradation of the final product due to uneven flow rate and uneven reaction rate in the application of the product.

In addition, workability is poor, such as the introduction and management of molten raw materials, which are operations of batch and semi-continuous reactions.

As a method of improving the problem of the French method, a method of continuously oxidizing and oxidizing molten zinc by reaction heat generated during oxidation of zinc vapor and air (Patent Document 1), and oxygen containing zinc powder having an oxide film on the surface Method of producing zinc oxide by heat treatment in atmosphere (Patent Document 2, Patent Document 3), gaseous zinc is produced using an inert gas, moved to an oxidation reaction region and oxidized with an oxygen-containing gas and then a special inert gas It is cooled by heating to obtain zinc oxide, and a method (Patent Document 4) and the like have been proposed.

In addition, as a wet method, a method of obtaining zinc carbonate by reacting zinc sulfate or zinc chloride with a carbonate such as sodium carbonate, and roasting it to obtain zinc oxide (Patent Document 5) is known, but this method has the advantages of high purity and specific surface area. However, the treatment cost is high, and the reaction process is complicated and is not widely used in industry.

Patent Document 1: Publication No. 2003-67630

Patent Document 2: Patent Publication No. 1993-7857

Patent Document 3: Patent 136901

Patent Document 4: Japanese Patent Application Publication No. 2007-161580

Patent Document 5: Japanese Patent Laid-Open No. 2002-284527

In the above-mentioned prior art, several batch-type evaporators are used to improve low energy efficiency due to burner type of oil or gas type which requires low work efficiency and high maintenance cost in batch or semi-continuous reaction mode. Oil and gas type requiring high maintenance cost and introduction of heat exchanger device to recover waste heat remaining in evaporation furnace to reduce excessive heat supply and loss due to burner type. Although efforts have been made to install expensive devices such as high-frequency electric furnaces that replace high-speed burners to achieve high heating rates, there are no fundamental solutions to problems caused by batch or semi-continuous reaction patterns. .

In addition, due to the air flowing into the batch and semi-continuous type, the evaporator is sealed and the inert gas, which is a carrier gas, is supplied to zinc evaporation to improve the low productivity due to the oxide film on the surface. Although efforts are being made to increase the amount produced, the price of zinc oxide is also increased due to the high cost-weight ratio in the production of inert gas.

In order to achieve a uniform shape, devices such as the use of inert gas and the introduction of oxygen into the oxidation reaction proceed with the oxidation reaction, but the difficulty of production management and the efficiency are not high due to the complexity of the control of the additional equipment and the gas supply process. Not suitable for production

As a result, these techniques are insufficient to improve the energy efficiency and uniformity of the productivity and quality of the manufacturing process compared to the production due to batch or semi-continuous zinc oxide production.

Accordingly, an object of the present invention is that there is no additional energy supply for reheating up to the evaporation temperature of the low melt temperature due to the batch or semi-continuous process configuration, which is a problem of the prior art described above, thereby increasing the low productivity efficiency. The invention provides a device and method for the continuous production of uniform zinc oxide free from byproducts such as whiskers without the need for process development and additional production elements such as carriers, combustion and cooling gases.

In order to solve the above problems, the inventors first build a fireproof wall with refractory on the outside of the evaporation furnace as shown in FIG. 4 or FIG. First means for maintaining a constant temperature of the evaporation furnace by installing a heater, forming a raw material inlet in front of the evaporation furnace, and installing a closed evaporation furnace for forming a discharge port for discharging zinc vaporized in the rear;

In order to continuously feed the raw material zinc into the melting furnace, a device for continuously measuring the amount of molten zinc present in the evaporating furnace is installed to measure the level of molten zinc in the evaporating furnace, and the measured value is sent to the control unit. A control unit that allows molten zinc to continuously enter the evaporation furnace in an amount that is reduced by vaporization of the molten zinc in the evaporation furnace, and the zinc ingot as a raw material is introduced into the melting furnace through the raw material inlet as the molten zinc in the melting furnace is reduced. The second means for automatically supplying the zinc ingot as a raw material in the raw material input unit into the melting furnace by installing the, and the molten zinc in the melting furnace to automatically transfer the molten zinc in the evaporation furnace by the amount insufficient. And

Oxidation reaction by injecting oxygen or air directly into the evaporation furnace, as described above, zinc oxide covers the surface of the molten zinc, so poor contact of oxygen, zinc oxide on the crucible inner wall surface and short evaporation due to reaction In order to solve problems such as lifespan and frequent repairs, it is necessary to fill the melt to prevent air from entering the evaporation inlet and install an air / oxygen inlet at a predetermined part of the pipe where zinc vaporized by evaporation is discharged from the evaporation furnace and moved. And zinc oxide react with gaseous zinc and air / oxygen in the pipeline in the middle of the settling tank, and the formed zinc oxide is transferred to the settling tank by the intake force of the exhaust fan installed on the dust collector. It suppresses the formation of oxide film and heat generation on the surface of the melt, and keeps the internal temperature and evaporation constant. The present invention has been completed by a third means for continuously obtaining zinc oxide in the form of uniform loading.

According to the method and apparatus of the present invention, since the evaporator starts to evaporate after the melt is filled, there is no air inflow from the raw material inlet side, and there is no air inflow from the outlet port due to the vapor pressure of zinc, so that the evaporator is oxidized to the surface of the melt inside the evaporator. It can suppress the formation of the film, thereby suppressing the decrease in productivity. In addition, it is possible to suppress the formation of airflow due to the difference between the air inflow and the dust collection suction pressure, and cooling of the melt due to cold air inflow.

As the evaporation of zinc proceeds, the height of the melt gradually decreases. At this time, the melt level meter installed at the melt inlet side continuously measures this level and sends a signal to the calculator, and the calculator judges the time when it is lower than the setting height. Send to order the input.

The continuous operation of level measurement, calculation (judgment), and feeding command causes the melt to be injected as much as the quantity insufficient due to evaporation as a certain amount naturally falls through the melt transfer path and flows into the evaporator continuously. Therefore, the heater compensates the amount of heat required for evaporation, and additionally a small amount of continuous inflow and heat loss, so there is no need for overheating, and prevention and stabilization of the production of by-products such as boiling of the melt and whiskers due to overheating The occurrence of temperature deviation up to temperature can be suppressed, and as a result, the temperature in the evaporation furnace can be kept constant.

As the removal of the elements that impede the uniformity and productivity, the conditions of evaporation and reaction become constant, and as a result, the formation of by-products such as acicular zinc oxide is suppressed, the size of primary particles becomes uniform, and energy Productivity and energy efficiency are improved.

The vaporized zinc is discharged through the evaporator outlet, through which the oxidation reaction proceeds in contact with the air introduced into the oxidation reaction zone, whereby zinc oxide is formed, and the produced zinc oxide is collected through the fixing tank and the cyclone.

Hereinafter, a device for producing zinc oxide according to the present invention will be described in detail with reference to FIGS. 1 to 4.

1 shows a block diagram of zinc oxide production according to the invention. In FIG. 1, zinc is melted, vaporized (evaporated), and the obtained gaseous zinc is reacted with air or oxygen (hereinafter simply abbreviated as “oxygen”) to obtain zinc oxide, cool it, and then collect it. This is a known method.

Using the conventional method and the apparatus thereof, as described above, different by-products such as acicular zinc oxide can be produced, and the primary particle size and shape are not uniform and energy production can be improved in comparison with FIGS. As shown in FIG. 4, a melt level meter for measuring the level of molten zinc in the crucible 121 of the evaporation furnace so that the raw material input unit 20, the melting furnace 110, and the evaporation furnace 120 may be continuously progressed. 12) is attached to measure the amount of evaporation, and transmitted to the control unit 11 to attach the corresponding software for controlling / injecting the raw material input from the raw material input unit 20. 4 and 5 will be described in detail below.

2 is a schematic overall configuration diagram of a zinc oxide continuous production apparatus according to the present invention.

That is, in the present invention, as shown in Figures 2, 3 and 4, after the ingot of zinc metal as a raw material is injected into the melting furnace 110, the zinc metal melted at 700 ~ 800 ℃ evaporated at 950 ~ 1200 ℃ After being transferred to the furnace 120, the molten zinc is vaporized, and the vaporized zinc is transferred to the fixing tank by vaporization of vaporized gas and suction of an exhaust fan installed above the dust collector, and between the reactor and the fixing tank. Air is injected from the formed air inlet to cause an oxidation reaction with vaporized zinc during transport to the fixing tank to form zinc oxide. The zinc oxide thus formed is transferred to the fixing tank, is fixed in the fixing tank 140, and part of the zinc oxide falls to the conveying conveyor 180 through the outlet of the lower part, and some of the zinc oxide is transferred to the cyclone tank 150, and again the cyclone tank ( At 150, a portion falls to the transfer conveyor 180, and a portion is sent over the cyclone tank 150 to the transfer conveyor 180 down through the dust collector 160. Here, only the schematic overall configuration of FIG. 2 will be described, and the raw material input unit 20, the melting furnace 110, the evaporation furnace 120, and the connecting portions thereof will be described later.

3 is a cross-sectional structural view showing a detailed structure from the raw material input portion to the fixing tank 141 in the zinc oxide manufacturing apparatus according to the present invention. 4 is a cross-sectional structural view showing another embodiment.

As shown in FIG. 3, in the present invention, the raw material input unit 20, the melting furnace 110, the evaporation furnace 120, the melt level measuring device 12, the control unit 11, the melting furnace discharge port 113, and the evaporation furnace Exhaust port 127, consisting of an exhaust pipe (P) connected to the outlet 127 by evaporation, its configuration, operation will be described in detail.

The input of the zinc ingot 21, which is a raw material, into the melting furnace is input from the raw material input unit 20 to the melting furnace 110 by the control unit 11. At this time, the raw material input part 20 is performed by well-known means, such as a lift. Melting furnace 110 has a melt cover 111 is installed to prevent the splashing of the zinc ingot at the top, the life of the size enough to pass through the zinc ingot injected by the automatic injector on the side of the melt warmer. The zinc ingot is introduced into the melting pot 112 through the hole.

The melting furnace 110 maintains the temperature of the melting pot 112 of the melting furnace at 600 ~ 800 ℃ by placing an electric heater. The melting point of zinc is 419.5 ° C, but zinc is not sufficiently melted at this melting point, and this temperature is different from the temperature of the crucible 121 in the evaporation furnace 120 connected to the melting furnace, thereby lowering the temperature of the evaporation furnace. Therefore, it is preferable to keep the above-mentioned temperature and to melt.

The molten zinc in the smelting furnace 110 is supplied with zinc ingot from the raw material feeder to the melter according to the command of the melt level gauge 12, and overflows and falls through the melter outlet 113 as the volume of the melt increases. It is transferred to the evaporation furnace 120 through the discharge line 113. The length of the discharge port 113 is preferably set so as not to be too long, and the heater 114 is attached so that there is no temperature loss during discharge. The temperature of this heater 114 is maintained at 50-100 degreeC higher than the temperature of the melting furnace 110, Especially preferably, it is higher than the temperature of the melting furnace.

In this way, the molten zinc is transferred to the crucible 121 of the evaporation furnace 120.

The evaporation furnace 120 includes a crucible 121 having an inlet 125 through which molten zinc is introduced at one side and an outlet 127 at the other side thereof, and an outer wall of the evaporation furnace 120 is a housing. And a housing 112 is separable from the evaporation furnace 120, and the housing 122 is filled with a refractory 123 made of heat resistant fiber such as ceramic, and the like. Insulating material 124 is installed on the outside. In addition, in the refractory 123 around the crucible 121, a coil-type electric heater 126 that generates heat by electric resistance is mounted.

The evaporation furnace 120 of the structure according to the present invention is a decomposable structure, so the maintenance and repair cost is lower than that of the conventional crucible structure. In other words, the reactor using a conventional burner has to be dismantled in order to separate the crucible only by dismantling all the fuels including the refractory and the complex structure. In the evaporation furnace 120 according to the present invention, since the refractory 123 is filled with fibers such as ceramics, when the evaporation furnace 120 needs repair or replacement, the inlet 125 is opened to open the crucible 121. ) Only need to be separated from the housing 122, and there is no need to disassemble some or all of the housing 122, the refractory 123, the electric heater 126, and the like.

In the evaporation furnace 120 having such a structure, the zinc melt introduced into the crucible 121 is heated to about 950 to 1300 ° C. by the electric heater 126 to be vaporized, and the vaporized zinc is collected as shown in FIG. 2. It is conveyed to the fixing tank 140 through the discharge port 127 by suction of the exhaust fan 170 provided above. The outlet 127 is formed to be inclined upward at about 10 to 60 °, preferably at about 20 to 40 °, to facilitate zinc vapor to be transferred to the exhaust pipe (P). A predetermined portion of the exhaust pipe P connected to the exhaust port 127 is not particularly limited, but the air inlet port 128 is connected to a position about 30 to 80 cm from the exhaust port. There is no need to install a blower specifically for air injection. That is, the air can be sufficiently sucked by the suction of the exhaust fan 170 installed above the dust collector 160, the exhaust pipe (P) from the outlet 127 of the crucible 121 of the air and the evaporation furnace 120 so sucked The vapor phase zinc transported to) reacts instantaneously to form zinc oxide.

4 is another embodiment of the present invention, which is different from FIG. 3 in that the chamber 130 is installed at the outlet 127 of the evaporation furnace 120, and air is sucked from the air inlet 131 of the chamber to discharge the outlet. The gaseous zinc discharged from 127 is oxidized in the chamber 130 to form zinc oxide, and the generated zinc oxide is transferred to the fixing tank 140 through the outlet 132 of the chamber. The chamber 130 is preferable because there is an advantage in mitigating the problems caused by such high temperature since the temperature rises to about 1500 ° C. due to the exothermic reaction when the gaseous zinc and air generate zinc oxide by reaction.

The ultrafine powdered zinc oxide formed as described above is transferred to the fixing tank 140 as shown in FIG. 2. In the fixing tank 140, zinc oxide is stabilized, and the stabilized zinc oxide is transferred to a collecting device (not shown) through a conveying screw 180 installed at a lower portion through a valve 141 installed below the fixing tank 140. On the other hand, zinc oxide, which is present in the form of ultra-fine powder in the fixing tank 140, is transferred to the cyclone tank 150 by the operation of the exhaust fan 170, and is uniformly sized by the vortex in the cyclone tank 150. As a result of the furnace aggregation, a part is transferred to the collecting device through the lower feed screw 180 through the valve 151 installed under the cyclone tank 150. The zinc oxide still present in the ultrafine powder form in the cyclone tank is conveyed back to the dust collector 160 and is passed through the filter 161 to the collecting device through the lower feed screw 180.

Figure 5a is an electron micrograph showing the shape of the zinc oxide obtained by the continuous evaporation and continuous input of the raw material in the evaporation furnace according to the present invention, Figures 5b to 5c using the present invention, the raw material is added in a semi-continuous manner 5D is an electron micrograph showing the shape of the zinc oxide obtained by the prior art batch method.

Figure 6 shows the spectrum of the X-ray diffraction analysis of zinc oxide obtained by the temperature of the crucible by evaporation according to the present invention and zinc oxide obtained by the prior art.

Hereinafter, an Example and a comparative example are given and this invention is demonstrated in detail. However, these examples do not limit the scope of the present invention.

Example 1

In the apparatus of the present invention shown in Fig. 4, the control unit is operated to keep the zinc ingot of purity 99.99% from the raw material inlet in a 500-liter melt pot 112 of a capacity maintained at 750 ± 5 ° C. by an electric resistance heater. The molten zinc was injected into a crucible 121 to an evaporation furnace with a capacity of 500 liters, which was maintained at 1250 ° C. by an electric resistance heater. The molten zinc in the crucible is evaporated to gaseous zinc and is discharged to the exhaust pipe P through the exhaust port 127 by the exhaust fan 170 connected to the dust collector 160 and reacts with the air coming from the air inlet pipe installed in the exhaust pipe. The ultrafine powdered zinc oxide formed therein was carried out while maintaining the suction negative pressure from the fixing tank 140 and the fixing tank 140 to the cyclone 150 and the dust collector 160. The ultrafine powdered zinc oxide was made into mature zinc oxide through a fixing tank 140, a cyclone 150, and rotary valves 141, 151, and 162 below the dust collector 160 for 24 hours. Zinc oxide was collected.

On the other hand, while continuously measuring the level of molten zinc in the crucible 121 of the melting furnace with the melt level meter 12, the amount of molten zinc evaporated and exited through the outlet 127 is transmitted to the controller 11, and the controller In (11), zinc oxide was continuously manufactured by instructing the raw material input unit 20 to inject zinc ingot into the melting furnace 110 and continuously injecting molten zinc into the crucible 121 of the evaporation furnace. At this time, the temperature of the heater 114 was maintained at 750 ± 5 ° C. in order to prevent the molten zinc in the melting furnace 110 from dropping in the discharge furnace 113.

The reaction was run continuously for 7 days under the same conditions.

Electron microscope of primary shape analysis of zinc oxide and amount of zinc ingot to be added for 7 days during operation to compare the productivity, by-product formation and average particle diameter of zinc oxide production method of Comparative Example The secondary particle size of the particle size analysis of the photo-laser method was confirmed.

Quantity of zinc ingot committed: 3.6 ton / day

Amount of zinc oxide obtained: 4.5 ton / day

Electron micrograph: FIG. 5A

X-ray diffraction spectrum: FIG. 6

Comparative Example 1

By using the same apparatus as in Example 1, the zinc ingot as a raw material was manually added to the inlet as the melt was reduced in the inlet by the evaporation at an interval of 1 hour without the automatic raw material input through measurement and determination of the melt level. The same operation was carried out except that it flowed into the evaporation furnace by a natural drop method.

The amount of zinc ingot injected during the operation, the amount of zinc oxide obtained, the electron micrograph of the primary shape analysis of zinc oxide, and the secondary particle size of the particle size analysis of the laser method were confirmed.

Quantity of zinc ingot committed: 3.2 ton / day

Amount of zinc oxide obtained: 4 ton / day

Electron micrograph: Fig. 5b

X-ray diffraction spectrum: FIG. 6

Comparative Example 2

By using the same apparatus as in Example 1, the melt was not completely filled so that air could be introduced into the inlet by evaporation, and the evaporation furnace could be seen from the inlet at an interval of 1 hour without automatic raw material input through measurement and determination of the melt level. The same operation was carried out except that zinc ingots as raw materials were manually added to the inner bottom, and the melt of the melter was overflowed to be introduced into the evaporation furnace by a natural drop method.

The amount of zinc ingot injected during the operation, the amount of zinc oxide obtained, the electron micrograph of the primary shape analysis of zinc oxide, and the secondary particle size of the particle size analysis of the laser method were confirmed.

Quantity of zinc ingot committed: 2.1 ton / day

Amount of zinc oxide obtained: 2.6 ton / day

Electron micrograph: Fig. 5c

X-ray diffraction spectrum: FIG. 6

Comparative Example 3

1.6 ton of zinc ingot of 99.99% purity was placed in the molten metal, and the molten zinc was heated to about 750 ° C to melt, and the molten zinc was placed in an evaporator, and when it reached 1250 ° C using an electric heater, it began to evaporate. Evaporation and oxidation were carried out in contact with the air inside the reactor, and zinc oxide reacted with the evaporated zinc and air was moved through the outlet and collected by collecting the settling tank and cyclone in the dust collector.

The melt is injected into the furnace by injecting zinc ingot into the furnace when the amount of melt in the evaporator drops from 50% of the height (volume) to less than 40% of the evaporator. Drive.

The method described above was carried out as it was to confirm the amount of zinc ingot, the amount of zinc oxide obtained, the electron micrograph of the primary shape analysis of zinc oxide, and the secondary particle size of the particle size analysis of the laser method.

Quantity of zinc ingot committed: 0.48 ton / day

Amount of zinc oxide obtained: 0.6 ton / day

Electron micrograph: Fig. 5D

X-ray diffraction spectrum: FIG. 6

The said Example and a comparative example are put together in Table 1 below.

TABLE 1

Evaporation condition Of raw material (zinc)
input
speed Zinc oxide
output
(ton /
7day) Zinc oxide
Average
output
(ton / day) Of raw material (zinc)
Daily average
input
(ton / day) Of raw material (zinc)
unit
input Needle-shaped
Oxidation
zinc
produce
The presence or absence 2nd insertion size (um)
(Average/
Top) Uptime in
condition Example 1 evaporation continuity
Control
input 31.5 4.5 3.8 20kg / 7.5 minutes radish 0.9 / 6 7 days Good Comparative Example 1 evaporation Semicontinuous
input 26.6 3.8 3.2 134kg / hr U 1.2 / 12 7 days Good Comparative Example 2 Fever
Oxidation, evaporation Semicontinuous
input 17.5 2.5 2.1 87kg / hr U 1.5 / 16 7 days damaged Comparative Example 3 Fever
Oxidation, evaporation arrangement
input 4.2 0.6 0.48 20kg / 1hr U 2.4 / 20 7 days damaged

* Melting Furnace Temperature: 750 ℃

* Evaporation Furnace Temperature: 1250 ℃

* Production operation day of Comparative Example 2: 7 days

As a result of confirming the inside of the evaporation furnace and the reactor used in Example 1 and Comparative Examples 1, 2 and 3, the device of the present invention is almost intact, and there is no problem in using it for one to two years later. In the reactors of Comparative Examples 2 and 3, the walls of the reactors were covered with zinc oxide residue and other inorganic oxides.

1 shows a block diagram for producing zinc oxide according to the present invention.

Figure 2 schematically shows the overall configuration of the zinc oxide production apparatus according to the present invention.

Figure 3 is an enlarged cross-sectional view showing a detailed structure of an embodiment of the melting furnace and the evaporation furnace of the present invention.

4 is an enlarged cross-sectional view of an embodiment in which a chamber is attached to an outlet through which gaseous zinc is discharged in the evaporation furnace of FIG. 3.

5 is an electron micrograph of zinc oxide obtained in accordance with the present invention (FIG. 5A), an electron micrograph of zinc oxide obtained in Comparative Example (FIGS. 5B and 5C), and an electron micrograph (FIG. 5D) by a conventional arrangement method. Indicates.

Fig. 6 shows the X-ray diffraction analysis (XRD) spectra of zinc oxide obtained in accordance with the present invention and zinc oxide obtained in Comparative Examples 1, 2 and 3.

Claims (7)

In the method for producing zinc oxide by melting and vaporizing the metal zinc to contact with oxygen or air to form zinc oxide, and through the fixing tank, cyclone tank, dust collector, In order to continuously feed raw zinc into the melting furnace, the remaining amount of molten zinc present in the evaporation furnace is measured by using a melt level meter. The measured value is sent to the control unit, and the control unit continuously causes the molten zinc to enter the evaporation furnace in the melting furnace by the amount of vaporization of the molten zinc in the evaporation furnace and decreases the zinc ingot as the raw material as the molten zinc in the melting furnace is reduced. The raw material is continuously introduced into the melting furnace through the inlet, and the melt is continuously heated by an electric heater method, and the zinc is vaporized to discharge gaseous zinc to the outlet of the evaporation furnace, and is operated by an exhaust fan connected to the dust collector of the evaporator. A method of continuously producing particulate zinc oxide, characterized in that to produce zinc oxide by causing an oxidation reaction with the air injected from the air inlet connected to the discharge pipe through the gaseous zinc discharged through. The method of claim 1, A process for the continuous production of particulate zinc oxide, characterized in that it measures the amount of residual melt at the inlet by evaporation. The method of claim 1, A method for continuously producing particulate zinc oxide, characterized in that the input time is determined by receiving a signal from the melt level measuring device, and a continuous input of the ingot is performed by a command to the raw material input machine. The method of claim 1, The zinc oxide obtained by the oxidation reaction further comprises the step of collecting through the fixing tank, cyclone tank, dust collector. A melting furnace 110 for melting metal zinc; In order to heat and melt the melt, it comprises a crucible 121 having an inlet 125 for injecting the melt and an outlet 127 for discharging the vapor, and comprising a housing 122 that can be separated as an outer wall of the crucible. The refractory 123 is filled in the housing 122, and the insulation 124 is installed outside the refractory 123, and the electric resistance heater 126 is mounted in the refractory 123 around the crucible 121. Evaporation furnace 120; An air injection pipe 127 positioned in an exhaust pipe P to inject air to oxidize gaseous zinc discharged from the crucible 121 to the evaporation furnace; A collecting device for collecting the ultrafine powdered zinc oxide; And Evaporation, continuous production apparatus of particulate zinc oxide consisting of an exhaust fan 170 for applying a negative pressure to the air injector and collector. The method of claim 5, The collection device, a fixing tank 131 for collecting zinc oxide, Cyclone tank 132 for vortexing zinc vapor discharged from the fixing tank, Dust collector 133 equipped with an exhaust fan 170 for sucking the zinc gas on one side; The fixing tank 131, the cyclone tank 132, the dust collector 133 is installed at each lower end of the continuous production apparatus of particulate zinc oxide consisting of a screw 170 for transferring the zinc oxide collected in each tank. The method according to claim 5 or 6, Apparatus for continuous production of particulate zinc oxide, characterized in that for discharging the chamber 130 for air injection at the outlet of the evaporation furnace.

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