JP4121796B2 - Melting method and melting furnace using oxidation exothermic material - Google Patents

Description

[0001]
  The present invention relates to a melting method for melting incineration ash generated when incinerating general waste or municipal waste, and in particular, melting is performed using heat generated from an oxidation heat generating material.In the melting methodRelated.
[0002]
[Prior art]
At present, municipal solid waste including municipal waste is collected from ordinary households by garbage trucks, transported to large municipal waste incineration facilities operated by local governments, etc., and fossil fuels such as heavy oil are used in incinerators within the incineration facilities. Incinerated by the main heat source.
[0003]
The incineration ash generated after incineration contains a large amount of harmful heavy metals such as chromium and lead, so the incineration ash can be disposed of in a closed-type waste disposal site or using a fossil fuel blast furnace. Incineration ash is made harmless by using molten slab in a melting furnace of a type or an arc type melting furnace using electric energy as a heat source and reused for road aggregates.
[0004]
For example, when incineration ash is processed using an arc melting furnace, the incineration ash 1 is pulverized to a predetermined size by a pulverizer 100 as shown in FIG. It is transported to the charging device 400 and charged into the molten slag pit 900 in the melting furnace 800 from the supply device 500. Thereafter, when power is supplied from the power source 600 between the main electrode 700 and the melting furnace 800, an arc phenomenon occurs between the charged incineration ash 1 and the main electrode 700, and arc heat generation starts. Melts into a molten slag of 1500 ° C. or higher. The molten slag accumulates in the molten slag pit 900, and the molten slag overflowed from the molten slag pit 900 becomes a granulated slag by the cold water sprayed from the water nozzle 1000. The granulated slag is transported by the conveyor 300 and stored in the slag pit 1100, and is periodically discharged from the discharge device 1300 through the slag pit outlet 1200 and is effectively used for road aggregate and the like.
[0005]
Further, the exhaust gas generated from the melting furnace 800 flows into the temperature reducer 1400 by the suction force of the exhaust gas fan 1600 and is cooled to a temperature of 50 ° C. or less, and then flows into the dust collector 1500 to be separated into dust and gas. The separated dust is collected at the bottom of the dust collector 1500 and returned to the hopper 200. The gas is discharged from the chimney 1700 through the exhaust gas fan 1600 into the atmosphere. At this time, if there is a combustible component in the gas, it is reused as fuel for an incinerator or the like, and if there is a toxic component, it is made harmless by removing the toxic component and then released into the atmosphere.
[0006]
Recently, in addition to the above-mentioned incineration ash, a method of directly injecting general waste into the melting furnace has begun. The melting apparatus and method are substantially the same as those described above.
[0007]
Currently, the amount of incineration ash being processed by the melting furnace as described above is about 5% of the approximately 7.7 million tons of incineration ash generated every year. The current situation is buried in the field. However, in recent years, environmental problems have been highlighted, it is difficult to secure land for disposal sites, and landfill disposal is expected to be impossible within a few years. There is an urgent need to reduce landfill disposal.
[0008]
[Problems to be solved by the invention]
However, the melting furnace as described above performs continuous operation for 24 hours while efficiently generating and maintaining a high temperature of 1500 ° C. or higher. There was a problem that it took a great deal of money and a long time to build the building.
For this reason, only some municipalities in the metropolitan area are equipped with melting furnaces such as those mentioned above, both of which are installed adjacent to large municipal waste incineration facilities, and occurred in adjacent incineration facilities. Currently, incineration ash is mainly melted. These melting furnaces do not accept incinerated ash generated from other incinerators from the standpoint of preventing the diffusion of harmful substances.
[0009]
Currently, local governments and companies have more than 1000 small and medium-sized incinerators, and the current situation is that incineration ash generated from these incinerators can only be disposed of in landfills. Therefore, it has been desired to develop a method for efficiently melting the incineration ash adjacent to each existing incinerator.
[0010]
  The present invention has been made in view of the above circumstances, and by utilizing the reaction heat of the oxidation heat generating material and the heat of induction heating, the general waste or the incinerated ash is melted into slag in a small and medium-sized melting furnace. Is possibleMelting methodIt is intended to provide.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is characterized by including the following steps, paying attention to the heat generated by the oxidation heat generating material.
  As a first step, the incinerated ash generated when the general waste is incinerated is pulverized to a diameter of 50 mm or less to form a treated product.
  As a second step, the processed product is put into a melting furnace and heated to 300 ° C. by induction heating to remove moisture.
  As a third step, the ignition temperature rises due to the induction heating.300 ° CHigher igniter is incorporated and the specific gravity is 4 g / cm³The above solidified oxidation exothermic material is placed on the upper part of the treatment object.
  As a fourth step, the oxidation exothermic material isHigher than 300 ℃The ignition agent is ignited by heating by induction heating, and the heat of 1300 ° C. or higher generated from the igniter initiates a chemical reaction on the oxidation heat generating material having an ignition temperature of 1100 ° C. or higher to generate a temperature of 2000 ° C. or higher. Accordingly, the processed product is heated to 1600 ° C. or more and melted.
[0012]
  The invention method of claim 2No igniter incorporated and specific gravity 4g / cm ³ Solidified oxidation exothermic materialIt is characterized by having the 5th process of maintaining the inside of a melting furnace at the temperature of 1600 degreeC or more by performing additional addition of.
[0016]
According to the method of the present invention, after removing moisture from the general waste or incinerated ash by induction heating, the exothermic reaction of the oxidation exothermic material is started by induction heating and the general waste or incinerated ash is melted using the heat. By using an oxidation heat generating material, it becomes possible to continuously generate molten slag at a high temperature in a small-scale melting furnace as in a large-scale melting furnace.
[0017]
In addition, the molten state of the molten slag having a temperature of 1600 ° C. or more generated by the exothermic reaction of the oxidizing exothermic material can be maintained by continuing induction heating and additionally adding the oxidizing exothermic material.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The melting treatment of general waste or incinerated ash by the small and medium melting furnace according to the present invention will be described with reference to the drawings.
FIG. 1 shows a medium- and small-sized melting furnace equipment used in the melting process of the present invention, a melting furnace 10 for performing a melting process, an incineration ash charging hopper 30 for charging incineration ash to the melting furnace 10 and oxidation heat generation. The oxidation exothermic material charging hopper 40 for charging the material and the incineration ash hopper 50 for supplying the incineration ash to the incineration ash charging hopper 30 are mainly configured.
[0019]
The incineration ash hopper 50 has an incineration ash (processed) that has been crushed to a size of 50 mm or less by the incineration ash crusher 51 so that moisture is easily removed by induction heating when the incineration ash is put into the melting furnace 10. Material) 1a is supplied.
[0020]
The specific gravity of the incinerated ash charged into the melting furnace 10 through the incinerated ash charging hopper 30 is 1.5 g / cm.^ThreeThe above is suitable for induction heating. This is because the incinerated ash having a specific gravity contains 20% or more of metal scraps such as iron and aluminum, so that these metals are easily heated by induction heating.
Therefore, the specific gravity of the incineration ash crushed by the incineration ash crusher 51 is 1.5 g / cm.^ThreeIn the following cases, the specific gravity is 1.5 g / cm^ThreeAn appropriate amount of the metal scrap 2 is added into the incineration ash hopper 50 from the metal scrap hopper 52 and mixed by the mixing rotor blade 50a so as to become the above. In addition, the magnitude | size of the metal waste piece 2a to add is 50 mm or less which is the same as the magnitude | size of the incineration ash 1a grind | pulverized by the incineration ash crushing apparatus 51. FIG.
That is, the incineration ash hopper (mixing means) 50 is charged with the incineration ash 1a crushed by the incineration ash crusher 51 and the metal scrap 2a by the metal scrap hopper 52, and mounted in the incineration ash hopper 50. The material in the incineration ash hopper 50 is mixed by the rotation operation of the rotary blade 50a. An incineration ash hopper 50 is equipped with an incineration ash specific gravity measuring device 53 at the inlet of the incineration ash hopper 50 to measure the specific gravity of the incineration ash 1a supplied from the incineration ash crusher 51.
[0021]
The specific gravity measuring device 53 is a box-shaped container having a certain capacity, and is configured with a weight meter attached to the bottom so that the weight of the incinerated ash 1a placed therein can be measured. When this container is filled with the incinerated ash 1a supplied from the incineration ash crushing device 51, the supply of the incinerated ash 1a from the incineration ash crushing device 51 to the specific gravity measuring device 53 is stopped, and a specific gravity measuring device is provided by a weight meter. The weight of the incinerated ash is measured. And the value which remove | divided the measured weight by the capacity | capacitance of the specific gravity measuring device 53 is made into the specific gravity value of incineration ash. After the weight measurement, incineration ash is put into the incineration ash hopper 50 from the specific gravity measuring device 53.
[0022]
The specific gravity measuring device 53 is interlocked with the metal scrap piece hopper 52, and the metal scrap pieces are put into the incineration ash hopper 50 from the metal scrap piece hopper 52 according to the measured value of the specific gravity, and the incineration ash and the metal are fed by the rotary blade 50a. Mix the scraps.
[0023]
Incineration ash mixture generated by the incineration ash hopper 50 (incineration ash only when pulverized incineration ash has a specific gravity of 1.5 or more, or a mixture of incineration ash and metal debris when metal debris is added and mixed. Hereinafter, the incinerated ash mixture indicates this mixture) and is transported from the conveyor 54 to the incinerated ash charging hopper (incinerated ash supply means) 30 and stored temporarily.
[0024]
The incinerated ash charging hopper 30 is formed in a tapered shape, and a moisture content measuring device 31 for measuring the moisture content of the incinerated ash mixture is mounted on the inner wall of the inclined surface.
At a position adjacent to the incinerated ash charging hopper 30, an oxidation heat generating material charging hopper (heating material supplying means) 40 is installed. The oxidation exothermic material charging hopper 40 is divided into two chambers, and an oxidation exothermic material 41 in which an ignition agent is incorporated on one side and an oxidation exothermic material 43 in which an ignition agent is not incorporated on the other side are respectively stored. Yes. Above the oxidizing heat generating material charging hopper 40, an oxidizing heat generating material preliminary hopper 45 for replenishing the oxidizing heat generating material 4 is installed.
[0025]
When the melting process is started in the melting furnace 10, the incineration ash mixture and the oxidation exothermic material are supplied from the supply device 32 installed at the lower end position between the incineration ash charging hopper 30 and the oxidation heating material charging hopper 40. The molten slag pit 11 is put into the inside.
[0026]
A high frequency coil 12 is disposed around the molten slab pit 11 of the melting furnace 10, and induction heating of the incinerated ash is performed by electricity flowing from the high frequency power supply 13 to the high frequency coil 12.
[0027]
An infrared radiation thermometer 14 that can measure the temperature of the incinerated ash in the molten slag pit 11 in a non-contact manner is mounted on the side wall of the melting furnace 10 so that the temperature can be confirmed through the observation window 15.
However, the infrared radiation thermometer 14 cannot measure the temperature of the molten slag. This is because the flame rising from the molten slag covers the surface of the molten slag, so that the surface of the molten slag cannot be seen directly.
[0028]
For this reason, the infrared radiation thermometer 14 is used only for temperature confirmation at 300 ° C. The infrared radiation temperature and the supply device 32 are linked to each other, and when the infrared radiation temperature is measured at a temperature of 300 ° C., a drop signal of the oxidizing heat generating material 41 is sent from the infrared radiation temperature 14 to the supply device 32. Further, after checking the temperature of 300 ° C., the observation window for protecting the observation window 15 is closed.
[0029]
A discharge passage 16 for discharging the overflowed molten slag is provided below the melting furnace 10, and cold water is blown onto the molten slag by a water nozzle 17 mounted at the lower end of the discharge passage 16 to form a granulated slag. 18 is stored in the granulated slag pit 19. The stored granulated slag is periodically sent from the discharge device 21 through the granulated slag pit outlet 20 and is effectively used for road aggregate and the like.
[0030]
A temperature reducer 22, a dust collector 23, an exhaust gas fan 24, and a chimney 25 that constitute a device for discharging the generated exhaust gas are mounted above the melting furnace 10. The temperature reducer 22 lowers the temperature of exhaust gas, the exhaust gas fan 24 flows exhaust gas to the temperature reducer 22 by suction, and the dust collector 23 separates exhaust gas into dust and gas. A passage (not shown) for returning the separated dust to the incineration ash charging hopper 30 is connected to the bottom surface of the dust collector 23 so that the gas is discharged from the chimney 25 through the exhaust gas fan 24 into the atmosphere. ing.
At this time, if there is a combustible component in the gas, it is reused as a fuel for an incinerator or the like, and if there is a harmful component, the harmful component is removed and rendered harmless before being released into the atmosphere.
[0031]
2 (a) and 2 (b) are structural explanatory views showing the structure of the oxidation heat generating material used in the melting process of the present invention.
FIG. 2A shows the oxidation heat generating material 41 in which the ignition agent 42 is incorporated. The ignition agent 42 is incorporated in the central portion of the upper surface of the oxidation heat generation material 41 formed in a cylindrical shape. As the igniting agent 42, a commercially available toy smoke fire is used.
FIG. 2B shows an oxidation heat generating material 43 in which no igniter is incorporated, and is formed in a cylindrical shape.
[0032]
Oxidation exothermic materials 41 and 43 are self-heating materials that use the strong affinity of aluminum or silicon for oxygen. These 8 mesh or less powders are solidified by press molding and have a specific gravity of 4 g / cm.^ThreeThat's it.
[0033]
  Solidified to a specific gravity of 4g / cm³The oxidation exothermic material described above has a characteristic that the chemical reaction does not start unless the entire solid is heated to a temperature of 1100 ° C. or higher. This characteristic is that in the state of powder before solidification, if only a part of the powder is heated to 1100 ° C., the chemical reaction is chained.OccurrenceTherefore, it is superior compared to the need for handling.
  Moreover, even if reaction starts, it has the characteristic which raise | generates exothermic reaction gradually over time for 20 to 30 second, and generate | occur | produces the temperature of 2000 degreeC or more.
[0034]
In addition, it solidifies and the specific gravity is 4g / cm^ThreeThe oxidation heat generating material described above can be formed into various shapes depending on the molding method, and a solid product can be machined into a desired shape.
[0035]
Next, a procedure for melting incineration ash using the above-described melting equipment will be described with reference to FIGS. 1 and 3. FIG. 3 is a diagram showing the relationship between the heating time and the treatment object temperature when a combination of induction heating and oxidation exothermic material is used in a small and medium melting furnace.
First, the incineration ash 1 is pulverized to a size of 50 mm or less by the incineration ash crusher 51. This is to facilitate removal of moisture from the incinerated ash during induction heating in the melting furnace 10. The pulverized incineration ash is conveyed to the incineration ash charging hopper 30 through the incineration ash hopper 50 and the conveyor 54, and is charged into the molten slab pit 11 in the melting furnace 10 from the supply device 32.
[0036]
When electricity flows from the high-frequency power source 13 to the high-frequency coil 12, induction heating to the incinerated ash starts at 300 ° C. At this time, incineration ash having a content ratio of metal scraps such as iron and aluminum of 20% or more is suitable for induction heating. However, when the ratio is less than this, the efficiency of induction heating becomes worse.
[0037]
For this reason, in the case of incineration ash with a small proportion of metal scrap pieces, the metal scrap pieces 2 are added from the metal scrap piece hopper 52 to the incineration ash hopper 50, and the metal scrap pieces in the incineration ash hopper 50 are incineration ash 20. It mixes so that it may become a ratio of% or more. In addition, the magnitude | size of the metal scrap piece 2 to add is 50 mm or less which is the same as the magnitude | size of the grind | pulverized incineration ash.
[0038]
After the incinerated ash mixture is heated to 300 ° C. by induction heating and moisture therein is completely removed, an oxidizing heat generating material 41 in which an igniter is incorporated is introduced from the supply device 32.
The amount of the oxidation heat generating material 41 in which the igniting agent to be charged is incorporated is automatically calculated by a computer incorporated in the supply device 32 based on the expected weight and specific heat of the incinerated ash mixture after removing moisture. It can be done.
[0039]
For example, the specific heat of the oxidation heat generating material 41 is 4 g / cm.^ThreeWhen the above iron oxide and aluminum thermite agent is used to obtain 2000 ° C. molten slag, when the oxidation exothermic material itself is raised from 300 ° C. to 2000 ° C., the extra heat generated is 3100 J / g. In addition, since the average specific heat between 300 ° C. and 2000 ° C. of the incinerated ash mixture is about 0.9 J / g, in order to increase the temperature from 300 ° C. to 2000 ° C., 0.9 × 1700 = 1530 J / g The amount of heat is required. Accordingly, an appropriate weight ratio between the incinerated ash mixture excluding moisture and the oxidation exothermic material is about 1: 0.5 (1530/3100).
[0040]
The size of the oxidizing heat generating material 41 to be input is larger than that so as not to enter the incinerated ash mixture.
[0041]
The moisture content of the incinerated ash mixture can be easily measured in the incinerated ash charging hopper 30 by using the moisture content measuring device 31. For these reasons, the total weight of the incinerated ash mixture charged into the melting furnace 10 from the supply device 32 is increased by the moisture content weight. It should be noted that the amount of the oxidation heat generating material 41 that is actually added is an amount commensurate with the molten slag reaching a temperature of 1600 ° C. or higher and 2000 ° C. or lower.
[0042]
By continuing induction heating after the oxidation heat generating material 41 is charged, when the temperature of the ignition agent 42 of the oxidation heat generating material 41 reaches 350 ° C., the ignition agent 42 is ignited and a temperature of 1300 ° C. or higher is generated instantaneously. To do. Since the ignition temperature of the oxidation heat generating material 41 is 1100 ° C. or higher, the reaction of the oxidation heat generation material 41 starts with the ignition of the igniter 42. By this reaction, a molten metal having a temperature equal to or higher than 2000 ° C., which is the same weight as the charged oxidation heat generating material 41, is generated and penetrates into the incinerated ash mixture and melts.
[0043]
Further, by continuing the induction heating, heat is applied to the molten slag to promote melting. Further, as a feature of induction heating, when an induced current acts on a melt containing a metal such as iron, it functions to convectively stir the molten metal. Combined with this, the molten slab pit 11 in the melting furnace 10 accumulates an incinerated ash mixture of 1600 ° C. to 2000 ° C. and molten slag in which the oxidation heat generating material 41 and the like are melted.
[0044]
From the time when molten slag is formed in the molten slab pit 11, the incinerated ash mixture is sequentially and continuously charged. By this charging, the temperature of the molten slag gradually decreases. When the temperature reaches 1600 ° C., an amount of the oxidizing heat generating material 43 required to raise the temperature again to 2000 ° C. is charged at a time. At this time, the oxidizing heat generating material 43 used does not include an ignition agent. Since the reaction start temperature of the added oxidation exothermic material 43 is 1100 ° C. or more which is the same as that of the oxidation exothermic material 41, the reaction starts at the moment when it contacts the surface of the molten slag at 1600 ° C.
It should be noted that the amount of the oxidizing heat generating material 43 to be charged is an amount commensurate with the amount of heat necessary to raise the temperature of the molten slag that has reached 1600 ° C. in the molten slag pit 11 by 400 ° C. By repeating this, continuous operation can be performed.
In addition, if the molten slag is sufficiently accumulated in the molten slag pit 11 in the melting furnace 10, continuous operation can be performed even when incineration ash or general waste without adding metal scrap pieces is added.
[0045]
The amount of the oxidizing heat generating material 43 described above is 4 g / cm in specific gravity as the oxidizing heat generating material.^ThreeWhen using the above-mentioned thermite agent of iron oxide and aluminum, it is as follows.
The extra heat generated when the oxidation heat generating material itself is raised from 1600 ° C. to 2000 ° C. is 3800 J / g. Moreover, since the average specific heat of the molten slag between 1600 ° C and 2000 ° C is about 1.1 J / g, in order to raise the temperature by 400 ° C, a heat quantity of 1.1 x 400 = 440 J / g is required. is there. Therefore, if the weight of the molten slag in the melting furnace is 100000 g, the necessary weight of the oxidation heat generating material is 440 × 100,000 / 3800 = 1579 g.
These data are input to the supply device 32 in advance, and the required amount of oxidation heat generating material 43 is automatically performed by the supply device 32.
[0046]
In addition, the water in the incinerated ash mixture that is sequentially added is instantaneously decomposed into oxygen and hydrogen in the high-temperature melting furnace 10 at 1600 ° C. or more, and this affects the chemical reaction of the oxidation exothermic material 43 that is subsequently introduced. Never give.
[0047]
Moreover, although the melting temperature of the incinerated ash mixture is about 1500 ° C., the molten slag in the melting furnace is kept at a temperature of 1600 ° C. or higher for the purpose of giving sufficient fluidity to the molten slag.
This temperature can be measured by the high frequency power supply control device 13. That is, when convection starts in the molten slag, the conductivity changes, and this change in conductivity gives a change to the value of the induced current. Since the electrical conductivity is determined by the temperature of the molten slag, the temperature of the molten slag can be easily known from the high-frequency power supply device 13 by measuring the relationship between the temperature of the molten slag and the change value of the induced current in advance.
[0048]
The high-frequency power supply control device 13 and the supply device 32 are linked to each other, and are configured such that when the temperature of the molten slag is lowered to 1600 ° C., a supply signal of the oxidizing heat generating material 43 is sent to the supply device 32.
And when the temperature of molten slag is 2000 degreeC or more, electricity supply from the high frequency power supply control apparatus 13 to the high frequency coil 12 is stopped. This is because it is not necessary to heat the molten slag to 2000 ° C. or higher.
[0049]
Further, the supply device 32 has a control unit, and an amount of the oxidizing heat generating material 43 necessary to raise the temperature in the melting furnace 10 is automatically charged into the melting furnace based on pre-input data. It has become so.
[0050]
The molten slag overflowed from the melting furnace 10 is made into granulated slag by the cold water sprayed from the water nozzle 17 and stored in the granulated slag pit 19, and is periodically carried out from the discharge device 21 through the granulated slag pit outlet 20. It is effectively used for road aggregates.
[0051]
Further, the exhaust gas generated from the melting furnace 10 flows to the temperature reducer 22 by the suction force of the exhaust gas fan 24, is cooled to a temperature of 50 ° C. or less, and then flows to the dust collector 23 to be separated into dust and gas. The separated dust is collected at the bottom of the dust collector 23 and returned to the incinerated ash charging hopper 30. The gas is discharged from the chimney 25 through the exhaust gas fan 24 into the atmosphere. At this time, if there is a combustible component in the gas, it is reused as fuel for an incinerator or the like, and if there is a toxic component, it is made harmless by removing the toxic component and then released to the atmosphere.
[0052]
According to the above-described melting method, since the melting method is a combination of induction heating and the reaction heat of the oxidation exothermic material, it is not necessary to heat the incineration ash mixture to 1600 ° C. only by induction heating, and it can be melted with a small power supply facility. Processing can be enabled.
That is, the inside of the melting furnace is heated to 350 ° C. by induction heating, and thereafter the igniter is ignited to generate reaction heat from the oxidation exothermic material, thereby heating and melting the incinerated ash mixture. A large power supply facility that needs to be heated up to 1600 ° C. only by heating is unnecessary.
[0053]
Further, according to this melting method, melting is completed in a short time if the temperature is raised to 350 ° C. by induction heating and a chemical reaction of the oxidation heat generating material occurs. Here, the reason why the oxidizing heat generating material is added when the temperature of the incinerated ash and the like is increased to 300 ° C. by induction heating is to prevent the oxidizing heat generating material from being affected by moisture such as the incinerated ash. The reason why the ignition temperature of the igniter is set to 350 ° C., which is 50 ° C. higher than 300 ° C., is to prevent oxidation exothermic material from reacting during charging in order to protect the supply device.
[0054]
FIG. 4 shows the relationship between the heating time and the treatment object temperature when only the induction heating of the small and medium melting furnace is used for the melting method described above.
When melting is performed only by induction heating, it is necessary to raise the temperature to a predetermined melting temperature. Therefore, when incineration ash contains 20% of metal scrap, a heating time of 12 hours is required.
In addition, if a large amount of incinerated ash is added after the temperature rises, the temperature drops, so the amount of incinerated ash input cannot be increased. For this reason, only a small amount of melting was possible for using a large amount of electricity for a long time.
[0055]
FIG. 5 is a diagram showing the relationship between the heating time and the treatment object temperature when only the oxidizing heat generating material is used in the small and medium melting furnace used in the above example. When melting only with an exothermic oxidation material, a temperature of 2000 ° C. or higher can be obtained in a short time. However, since the refractory material that constitutes the incinerated ash and the like always contains several percent of moisture, All of the water needs to be removed. This is because, in the chemical reaction of the oxidation exothermic material, if even a small amount of water is present, the water rapidly expands and a boiling phenomenon may occur, which may damage the melting furnace. For this reason, it is difficult to melt only the oxidation heat generating material.
[0056]
According to the method of the present invention, a melting furnace can be formed by combining an apparatus that can efficiently perform induction heating from room temperature to 350 ° C. and an oxidation heat generating material, so that it is 1600 ° C. as in the case of performing only induction heating. A large power supply facility that needs to be heated up to is not necessary.
In addition, a molten slab can be generated in a short time, and even if the temperature of the molten slab is lowered, it can be returned to a high temperature in a short time by introducing an oxidizing heat generating material, so a large amount of molten slag can be continuously produced even in a small melting furnace. The amount of incinerated ash treated can be increased if a large amount of oxidation heat-generating material is used.
[0057]
【The invention's effect】
According to the present invention, after removing moisture from the incinerated ash by induction heating, the oxidation exothermic material is reacted and the melting treatment is performed by reaction heat. The incineration ash can be efficiently melted in an unnecessary small melting furnace, and a molten slab can be generated at the same high temperature as the large melting furnace.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram of equipment configuration showing the equipment content of a medium and small melting furnace of the present invention.
FIGS. 2A and 2B show an oxidation heat generating material used in the method of the present invention, in which FIG. 2A is a perspective explanatory view of an oxidation heat generating material in which an ignition agent is incorporated, and FIG. It is a perspective view of material.
FIG. 3 is a diagram showing the relationship between the time and the temperature of the object to be treated when a melting process is performed by combining induction heating according to the method of the present invention and an oxidizing heat generating material in a small and medium melting furnace.
FIG. 4 is a diagram showing the relationship between the time and the temperature of a processed product when a melting process is performed using only induction heating in a small and medium melting furnace.
FIG. 5 is a diagram showing the relationship between the time and the temperature of a processed product when a melting process is performed using only an oxidizing exothermic material in a small and medium melting furnace.
FIG. 6 is an explanatory diagram of the structure of an arc melting furnace facility using conventional electric energy as a heat source.
[Explanation of symbols]
1 ... incineration ash, 1a ... incineration ash (processed product),
2 ... metal scrap, 2a ... metal scrap,
10 ... melting furnace, 11 ... molten slag pit,
12 ... high frequency coil, 13 ... high frequency power supply control device,
30 ... Incineration ash charging hopper (incineration ash supply means), 32 ... Supply device,
40 ... Oxidation exothermic material charging hopper (heating material supply means),
41 ... Oxidation exothermic material, 42 ... Ignition agent,
50 ... Incineration ash hopper (mixing means), 51 ... Incineration ash crusher,
52 ... Metal scrap hopper, 53 ... Specific gravity measuring instrument

Claims (2)

A first step of pulverizing incinerated ash generated when incinerating general waste into a diameter of 50 mm or less to form a treated product;
A second step of putting the treated product into a melting furnace and heating to 300 ° C. by induction heating to remove moisture;
Third step of covering an upper portion of the treatment object with a solid oxidation exothermic material in which an igniter whose ignition temperature is set higher than 300 ° C. which is a rise temperature by the induction heating is incorporated and whose specific gravity is 4 g / cm ³ or more. When,
The oxidation exothermic material is ignited by heating the oxidation exothermic material by induction heating higher than 300 ° C., and the heat of 1300 ° C. or higher generated from the igniter initiates a chemical reaction to the oxidation exothermic material having an ignition temperature of 1100 ° C. or higher. And a fourth step of heating the treated product to 1600 ° C. or higher and melting it by generating a temperature of 2000 ° C. or higher. Claim 5 having a fifth step of maintaining the inside of the melting furnace at a temperature of 1600 ° C. or higher by additionally charging a solid oxidation exothermic material having no specific ignition agent and a specific gravity of 4 g / cm ³ or higher. A melting method using the oxidation exothermic material according to Item 1.

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