JP2007277726A - Treatment device and treatment method for zinc-containing iron oxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of iron and to recover dust having a high zinc concentration. <P>SOLUTION: At least one selected from RDF (Refuse Derived Fuel) and RPF (Refuse Paper and Plastic Fuel) obtained from ASR (Automobile Shredder Residue), household electric appliance shredder dust, waste plastics and waste as waste effective as reducing materials to zinc-containing iron oxide fed into a furnace 2 and further generating calory required for reduction is introduced into the furnace 2. In a state where reducing materials other than the same are not used, heating treatment is performed; thus zinc is reduced from the zinc-containing iron oxide, so as to be separated, and further, iron oxide is reduced, so as to obtain metal iron. During the above process, the reducing temperature in the furnace 2 is controlled to 800 to 1,080°C, and then the phenomenon that copper having a melting point of 1,083°C is molten and stuck to iron is prevented; the degradation of the iron is prevented, and further, the zinc separated from the zinc-containing iron oxide is volatilized, and is scattered as dust with a fine particle size, so as to be recovered as dust having a high zinc concentration in which zinc is concentrated as zinc oxide. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for treating zinc-containing iron oxide.

Conventionally, for example, iron mill-generated dust containing zinc-containing iron oxide is used as a material to be treated, and the material to be treated and zinc oxide and iron oxide in the zinc-containing iron oxide are reduced, for example, carbonaceous materials (reducing material) such as coke. A mixture raw material mainly composed of A method of dezincing zinc-containing iron oxide using a rotary kiln that evaporates and obtains an iron-containing material that can be charged into a reduction furnace such as a blast furnace is known (for example, see Patent Document 1).
JP 2002-241850 A

  However, the iron-containing material obtained by the above method has a high content of impurities, and for example, it is desired to prevent deterioration of iron quality when used as an iron raw material in an electric furnace process.

  The present invention has been made to solve such a problem, and heat treatment of zinc-containing iron oxide and a reducing material separates zinc from zinc-containing iron oxide and reduces iron oxide to reduce metal iron. It is an object of the present invention to provide a processing apparatus and a processing method for zinc-containing iron oxide that can prevent the deterioration of the quality of iron and can collect dust having a high zinc concentration.

  Here, as a result of intensive studies, the present inventors have found that the deterioration of iron quality is caused by the fact that copper contained in the object to be processed melts and adheres to the iron content. .

  Accordingly, the zinc-containing iron oxide treatment apparatus according to the present invention heats the zinc-containing iron oxide and the reducing material in a reduction furnace, thereby separating zinc from the zinc-containing iron oxide and reducing the iron oxide to obtain metallic iron. A processing apparatus for zinc-containing iron oxide, wherein the reducing furnace introduces at least one of ASR, home appliance shredder dust, waste plastic, RDF, and RPF as a reducing material, and does not use any other reducing material The reduction treatment is performed at a reduction temperature of 800 to 1080 ° C. in the reduction furnace.

  In addition, the method for treating zinc-containing iron oxide according to the present invention heats the zinc-containing iron oxide and the reducing material in a reduction furnace, thereby separating zinc from the zinc-containing iron oxide and reducing the iron oxide to obtain metallic iron. A method for treating zinc-containing iron oxide, wherein at least one of ASR, home appliance shredder dust, waste plastic, RDF, and RPF is supplied as a reducing material, and the reducing treatment is performed without using any other reducing material. The reduction temperature of the reduction furnace is 800 to 1080 ° C.

  According to such a treatment apparatus and treatment method for zinc-containing iron oxide, it is a waste material that is effective as a reducing material and generates heat necessary for reduction with respect to zinc-containing iron oxide supplied into the furnace. At least one of ASR, home appliance shredder dust, waste plastic, RDF obtained from waste, RPF is supplied into the furnace, and heat treatment is performed without using any other reducing material. Zinc is reduced and separated from iron, and iron oxide is reduced to obtain metallic iron. At this time, since the reduction temperature of the furnace is 800 to 1080 ° C., it is possible to prevent copper having a melting point of 1083 ° C. from melting and adhering to iron, preventing deterioration of iron quality, and zinc. Zinc separated from the iron oxide contained is volatilized and scattered as dust having a fine particle diameter, and can be recovered as dust having a high zinc concentration in which zinc is concentrated as zinc oxide.

  Here, various types of reduction furnaces are employed, and a specific example of a furnace that makes the inside of the furnace a suitable reducing atmosphere is a rotary kiln.

  As described above, according to the present invention, it is possible to prevent deterioration of iron quality and to collect dust having a high zinc concentration.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a treatment apparatus and treatment method for zinc-containing iron oxide according to the present invention will be described with reference to the drawings. Drawing 1 is a lineblock diagram showing equipment provided with a processing unit of zinc content iron oxide concerning an embodiment of the present invention.

  As shown in FIG. 1, the facility 100 includes an electric furnace (electric furnace) 1, a rotary kiln (reduction furnace) 2 that introduces electric furnace dust and reducing material of the electric furnace 1 and heat-treats, and an outlet 2 f of the rotary kiln 2. A secondary combustion tower 3 that is communicated to complete combustion, a boiler (heat recovery device) 4 that exchanges heat by introducing exhaust gas from the secondary combustion tower 3, and a gas that cools the exhaust gas from the boiler 4 A cooling tower 5, a cyclone 6 that introduces exhaust gas from the gas cooling tower 5 and separates into solid and gas, a front bag filter 7a that collects dust in the exhaust gas from the cyclone 6, and an exhaust gas from the front bag filter 7a The exhaust gas treatment agent supply device 10 for supplying slaked lime and activated carbon as the exhaust gas treatment agent to the exhaust gas from the upstream bag filter 7a is communicated downstream from the supply position of the exhaust gas treatment agent. And a subsequent bag filter 7b for collecting.

  The facility 100 includes a magnetic separator 8 that sorts iron from the discharge discharged from the outlet 2f of the rotary kiln 2, and a copper sorter 9 that sorts copper from the discharge from which iron has been removed by the magnetic separator 8. I have.

  The electric furnace 1 is for producing steel by melting iron scrap as a raw material at a furnace temperature of 1300 to 1500 ° C., for example, and electric furnace dust is generated as fly ash from the electric furnace 1. Table 1 shows typical properties of the electric furnace dust.

  As shown in Table 1, the electric furnace dust has a total iron content (T-Fe) content of about 22%, a metal iron (M-Fe) content of about 0.8%, and an iron oxide content of 30. %, The zinc content is about 30%, and contains a large amount of zinc-containing iron oxide. Therefore, the electric furnace dust is taken up by the non-ferrous smelter in the same state as the waste.

  The rotary kiln 2 has a cylindrical rotating body 2a and is horizontally placed so as to be inclined downwardly from a front part (left side in the figure) on the inlet side to a rear part (right side in the figure) on the outlet side. Arranged. The rotary kiln 2 may be placed horizontally. The rotary kiln 2 has a front end portion of its body portion 2a closed by a front support portion 2b as a fixed portion and is rotatably supported, and a rear end portion of its body portion 2a as a fixed portion as a secondary combustion tower. 3 is supported rotatably.

  The front support portion 2b is provided with an introduction duct 2c for introducing the electric furnace dust from the electric furnace 1 into the furnace, and burns fuel such as kerosene using combustion air introduced into the furnace. A fuel combustion device 2d is provided. The introduction duct 2c is provided with a reducing material supply device 2e. The reducing material supply device 2e blows the reducing material into the furnace and supplies it to a predetermined position without stopping the operation of the rotary kiln 2.

  Here, the reducing material supplied by the reducing material supply device 2e is ASR (automobile-derived shredder dust), which is required to be processed by the Automobile Recycling Law. This ASR is an unselected or selected ASR, and typical properties are shown in Table 2.

  As shown in Table 2, ASR has a high content of volatile components such as hydrogen and hydrocarbons of about 50% and a fixed carbon content of about 4%. The ASR contains a relatively large amount of copper.

The rotary kiln 2 to which the electric furnace dust and ASR are supplied has an O ₂ concentration in the exhaust gas at the outlet 2f of 5% -dry or less in order to make the inside of the furnace a reducing atmosphere, and the reduction of the furnace to prevent melting of copper. The operation is controlled so that the temperature is 800 to 1080 ° C.

  In such a rotary kiln 2, the body 2a rotates at a predetermined speed, and the electric furnace dust supplied into the furnace via the introduction duct 2c is conveyed from the inlet side to the outlet 2f. The high-temperature combustion gas and flame generated in the combustion device 2d come into contact with the conveyed electric furnace dust and heat the electric furnace dust. Further, the ASR supplied into the furnace via the reducing material supply device 2e is heated to generate a heat amount necessary for reduction, and effectively functions as a reducing material.

  By this reducing action of ASR, zinc is reduced and separated from zinc-containing iron oxide in the electric furnace dust, and iron oxide is reduced to obtain metallic iron. At this time, since the reduction temperature of the furnace is set to 800 to 1080 ° C., it is possible to prevent copper having a melting point of 1083 ° C. from melting and adhering to iron. And the discharge containing iron and copper flows down from the outlet 2f and is discharged. On the other hand, the zinc separated from the zinc-containing iron oxide volatilizes and scatters as dust having a fine particle diameter, and is accompanied by the exhaust gas and travels to the secondary combustion chamber 3a above the kiln outlet 2 of the secondary combustion tower 3.

  Here, the blending ratio of the electric furnace dust (zinc-containing iron oxide) and ASR is preferably 1: 1 to 1:10, and particularly preferably 1: 4.

  The discharged material discharged from the kiln outlet 2 f is subjected to sorting of iron by the magnetic separator 8, and the iron is supplied as a raw material for the electric furnace 1. As described above, since this iron does not melt copper, it is effectively used as a raw material in which deterioration in quality is prevented. The electric furnace dust generated in the electric furnace dust 1 is supplied to the rotary kiln 2 as described above, and this is repeated.

  Further, the discharged material discharged from the kiln outlet 2f and from which iron has been removed by the magnetic separator 8 is subjected to copper sorting by the copper sorter 9, and the copper is used as a raw material for the copper refinery and is effectively used.

  On the other hand, in the secondary combustion chamber 3a, the unburned components in the exhaust gas are completely burned, and the volatilized zinc becomes zinc oxide or the like and goes to the subsequent stage as dust having a high zinc concentration in which zinc is concentrated.

  This dust passes through the boiler 4 together with the exhaust gas, and at this time, heat recovery is performed in the boiler 4 and effective utilization as a heat source is achieved. The exhaust gas that has passed through the boiler 4 is cooled to a predetermined temperature by the gas cooling tower 5 and then reaches the cyclone 6 where solid-gas separation is performed by the cyclone 6 and dust (solid matter) having a predetermined weight is separated from the exhaust gas. To be collected. The dust collected by the cyclone 6 is dust with a high zinc concentration.

  On the other hand, the exhaust gas that has passed through the cyclone 6 passes through the front-stage bag filter 7a, and at this time, dust that has not been collected by the cyclone 6 is collected by the front-stage bag filter 7a. The dust collected by the pre-stage bag filter 7a is also the high zinc concentration dust described above.

  The exhaust gas that has passed through the preceding bag filter 7a is supplied with slaked lime and activated carbon from the exhaust gas treating agent supply device 10, and harmful substances such as chlorine and sulfur in the exhaust gas are combined with the slaked lime, Hazardous substances such as dioxins are adsorbed on the activated carbon, and the exhaust gas containing activated slaked lime combined with the harmful substances and the harmful substances such as dioxin passes through the subsequent bag filter 7b. At this time, dust containing slaked lime and activated carbon Is collected by the post-stage bag filter 7b. The dust collected by the post-stage bag filter 7b is subjected to a landfill process or the like, passes through the post-stage bag filter 7b, and the gas that has been desalted, desulfurized, and dedioxin purified is passed through the chimney 11 of the post stage. Through the atmosphere.

  On the other hand, the high zinc concentration dust collected and recovered by the cyclone 6 and the pre-stage bag filter 7a has a zinc concentration of 50 to 80%, and is thus used extremely effectively as a raw material for crude zinc ore at a zinc refinery. . Incidentally, in the electric furnace dust from the electric furnace 1, the zinc concentration is about 30%.

  Thus, in this embodiment, the ASR, which is a waste material that is effective as a reducing material and generates the amount of heat necessary for reduction, is contained in the furnace with respect to the zinc-containing iron oxide supplied to the furnace. Supply and heat treatment to reduce and separate zinc from zinc-containing iron oxide and reduce iron oxide to obtain metallic iron. At this time, the reduction temperature of the furnace is set to 800 to 1080 ° C. Thus, it is possible to prevent the copper having a melting point of 1083 ° C. from melting and adhering to the iron, thereby preventing the deterioration of the iron quality, and volatilizing the zinc separated from the zinc-containing iron oxide. It can be recovered as dust having a high zinc concentration in which zinc is concentrated as zinc oxide by being scattered as fine particle dust.

  Here, Table 3 shows the results of experiments conducted by the inventors using the equipment shown in FIG. 1 using the electric furnace dust having the properties shown in Table 1 and the ASR having the properties shown in Table 2. Table 3 shows the properties of the discharge from the rotary kiln 2.

  As shown in Table 3, the total amount of iron content (T-Fe) is about 65%, the content of metallic iron (M-Fe) is about 60%, and the content of iron oxide is about 7%. It was confirmed that the zinc content was about 2%, the metal iron content was significantly increased, and the zinc content was significantly reduced.

  In addition, you may make it melt | dissolve the residue which removed iron and copper from discharge | emission, using the rotary kiln 2 which processed the zinc containing iron oxide as an oxidation melting furnace of about 1200-1300 degreeC, for example. The slag from the rotary kiln 2, which is an oxidation melting furnace, is effectively used, for example, as a roadbed material or a concrete aggregate.

  Here, the residue obtained by removing iron and copper from the discharge contains a large amount of carbon, silica, alumina, calcia, and the like. Therefore, the residue obtained by removing iron and copper from the discharge may be supplied to the electric furnace 1, and in this way, the carbon functions as a coke substitute (carburizing material), and silica, alumina, Calcia and the like are melted, and the slag from the electric furnace 1 is effectively used, for example, as a roadbed material or a concrete aggregate.

  In addition, the waste discharged from the rotary kiln 2 is screened, only the waste on the screen is screened for iron with a magnetic separator 8 and copper with a copper separator 9, and iron is used as a raw material for the electric furnace 1. You may make it provide copper as a raw material of a copper refinery, and when it does in this way, while the selected iron and copper are each utilized effectively, the handleability (handling) of iron and copper is improved.

  Moreover, you may make it melt | dissolve the discharge on the sieve which removed iron and copper from discharge, using the rotary kiln 2 which processed the zinc containing iron oxide as an oxidation melting furnace of about 1200-1300 degreeC, for example, In this case, the slag from the rotary kiln 2 that is an oxidation melting furnace is effectively used, for example, as a roadbed material or a concrete aggregate, and the handleability of the exhaust supplied to the rotary kiln 2 that is an oxidation melting furnace is improved. Be improved.

  Furthermore, the effluent on the sieve from which the iron and copper are removed from the effluent may be supplied to the electric furnace 1, and in this way, the carbon functions as a coke substitute (carburized material). At the same time, silica, alumina, calcia and the like are melted so that the slag from the electric furnace 1 is effectively used as, for example, a road base material or a concrete aggregate, and the handling property of the exhaust material supplied to the electric furnace 1 is improved.

  By the way, since ASR has a small amount of fixed carbon and a large amount of volatile matter as described above, it has the characteristics of a reducing material different from coke, which is a mass of fixed carbon. FIG. 2 is a diagram showing the change over time of the reducing function of ASR, which is a reducing material, together with the case where ASR is additionally supplied and compared with coke.

  In FIG. 2, the horizontal axis represents time, and the vertical axis represents the metallization rate (M-Fe / T-Fe). The solid line in the figure shows the change over time in the metallization rate when the mixing ratio of electric furnace dust and ASR is 1: 4 at a reduction temperature of 950 ° C., and the dotted line in the figure is the reduction temperature of 950 ° C. It shows the change over time in the metallization rate when the blending ratio of electric furnace dust and ASR is 1: 4, and ASR is additionally supplied in the middle to make the blending ratio of electric furnace dust and ASR 1:10. In addition, the dashed-dotted line in a figure has shown the thing by coke.

  As shown by a solid line in FIG. 2, ASR has a characteristic that it has a fixed carbon content and a large amount of volatile components. Therefore, the residence time of the zinc-containing iron oxide in the rotary kiln 2 is preferably 1 to 3 hours.

  FIG. 3 is a diagram showing the change with time of the zinc removal rate of the discharged matter. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the zinc removal rate of the effluent. The solid line in the figure shows the change over time in the zinc removal rate of the effluent when the reduction ratio of 950 ° C. and the blending ratio of the electric furnace dust and ASR is 1: 4. As shown in FIG. 3, it is preferable that the residence time of the zinc-containing iron oxide in the rotary kiln 2 is 1 to 3 hours also from the zinc removal rate.

  Thus, since ASR has a short function as a reducing material, it is preferable to additionally supply ASR to the rotary kiln 2 in order to maintain the function as the reducing material over time. When additional ASR is supplied in this manner, it has been confirmed that the reduction function is greatly extended as shown by the dotted line in FIG. In the case of additionally supplying ASR in this way, it is preferable to blow ASR into the location where the function of ASR in the rotary kiln 2 is lost using the reducing material supply device 2e.

  The present invention has been specifically described above based on the embodiment. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, electric furnace dust containing a large amount of zinc-containing iron oxide is used. It is intended to make efficient use of recovered iron and zinc by increasing the recovery rate of iron and zinc as the object to be treated. For example, sludge generated in wastewater treatment equipment, which is an electric furnace auxiliary equipment, rolling equipment In other words, it may be a rolling scale generated in the above, and the point is that it contains zinc-containing iron oxide.

  Further, in the above embodiment, the ASR which is obliged to be treated by the automobile recycling law and contains a large amount of copper is used as the reducing material, and satisfies the automobile recycling law and prevents the copper from adhering particularly to metallic iron. Although the action and effect of the present invention are further exhibited, it is obtained from ASR, home appliance shredder dust, waste plastic, and waste, which is a waste that is effective as a reducing material and generates heat necessary for reduction. At least one of RDF (Refuse Derived Fuel) and RPF (Refuse Paper and Plastic Fuel) may be used as the reducing material.

  Moreover, in the said embodiment, although the rotary kiln 2 is used as a furnace which forms a suitable reducing atmosphere in a furnace, if it is a furnace which functions as a reduction furnace, in a shaft furnace, a high temperature gasification furnace, etc., for example. There may be.

  In the above embodiment, the cyclone 6 and the two-stage bag filters 7a and 7b are installed in the subsequent stage of the reduction furnace (rotary kiln) 2, and the cyclone 6 and the front-stage bag filter 7a are used for chlorine, sulfur, and exhaust gas treatment agent. Dust containing high zinc concentration that is not included is collected and recovered and used for the zinc refinery. A cyclone 6 and a single-stage bag filter 7a are installed at the rear stage of the reduction furnace 2, and the cyclone 6 and the bag filter 7a The exhaust gas treatment agent is supplied to the exhaust gas line between the two, and the cyclone 6 alone collects and collects high zinc concentration dust that does not contain chlorine, sulfur and exhaust gas treatment agent, and supplies it to the zinc refinery. Alternatively, only the two-stage bag filters 7a and 7b are installed at the rear stage of the reduction furnace 2, and the exhaust gas treatment is performed in the exhaust gas line between the bag filters 7a and 7b. It is also possible to supply the agent, collect dust with a high zinc concentration not containing chlorine, sulfur, and exhaust gas treatment agent only with the front stage bag filter 7a, collect it, and use it for the zinc refinery. Can use the dust collected upstream from the most downstream bag filter as a raw material for the zinc refinery, and the zinc can be effectively used.

It is a block diagram which shows the installation provided with the processing apparatus of the zinc containing iron oxide which concerns on embodiment of this invention. It is a diagram which shows a time-dependent change of the reduction function of ASR which is a reducing material with the case where ASR is additionally supplied, and is compared with coke. It is a diagram which shows a time-dependent change of the zinc removal rate of discharge | emission.

Explanation of symbols

  2 ... Rotary kiln (reduction furnace; treatment device for zinc-containing iron oxide), 2e ... Reducing material supply device.

Claims (3)

A treatment apparatus for zinc-containing iron oxide that separates zinc from the zinc-containing iron oxide and reduces the iron oxide to obtain metallic iron by heat-treating the zinc-containing iron oxide and the reducing material in a reduction furnace,
The reduction furnace is
As the reducing material, at least one of ASR, home appliance shredder dust, waste plastic, RDF, and RPF is introduced, and reduction processing is performed without using any other reducing material,
The reduction | restoration temperature of the said reduction furnace shall be 800-1080 degreeC, The processing apparatus of the zinc containing iron oxide characterized by the above-mentioned.   The said reduction furnace is a rotary kiln, The processing apparatus of the zinc containing iron oxide of Claim 1 characterized by the above-mentioned. A method for treating zinc-containing iron oxide by separating zinc from the zinc-containing iron oxide and reducing the iron oxide to obtain metallic iron by heat-treating the zinc-containing iron oxide and the reducing material in a reduction furnace,
As the reducing material, supply at least one of ASR, home appliance shredder dust, waste plastic, RDF, RPF,
Perform the reduction process without using any other reducing material,
A method for treating zinc-containing iron oxide, wherein the reduction temperature of the reduction furnace is 800 to 1080 ° C.

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