Incineration processing method of synthetic wood and recycling method

Abstract

To provide an incineration treatment method capable of efficiently incinerating synthetic wood.SOLUTION: A method for incinerating synthetic wood containing fiber reinforced plastic that includes glass fiber material and having maximum dimension exceeding 1.5 m, comprising a first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less, and a second step of feeding the pieces into a rotary kiln and incinerating them at a temperature of 800°C to 1200°C for 0.5 to 1.5 hours to obtain incineration residue containing glass fiber material, characterized by having a heat reduction rate of the incineration residue of less than 10%.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for incinerating and recycling synthetic wood. [Background technology]

[0002] Synthetic wood is used in various fields as a substitute for natural wood due to reasons such as cost and ease of maintenance. For example, a large amount of synthetic sleepers are required to lay structures such as railways. Natural sleepers made from natural wood were used as sleepers, but nowadays, those made from fiber-reinforced plastics (FRP) are widely used as a substitute for natural sleepers because they do not need to worry about corrosion caused by rain or termites and are easy to maintain.

[0003] However, various FRP products, including synthetic sleepers, contain glass fibers as a reinforcing material, so that when they become waste, they are more difficult to dispose of than natural sleepers. Patent Document 1 (JP Patent Publication 10-085704) proposes a method for disposing of FRP waste in which the FRP waste is heated in an incinerator to oxidize and remove organic matter, and then immediately put into a short glass fiber raw material melting furnace or a rock wool raw material melting furnace. It is disclosed that this method has the advantage that the FRP waste can be used as a raw material for short glass fiber or rock wool, and that industrial waste is reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-085704 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the processing method disclosed in Patent Document 1 can be applied to small-volume items such as scraps, offcuts, and crushed FRP products, some synthetic wood is large in size, and most synthetic sleepers in particular are 2.6 m or longer in length, making it difficult to process them as is.

[0006] In addition, the incineration residue of synthetic wood containing fiber-reinforced plastics including glass fiber materials is rich in calcium, silicon, and aluminum, and if these elements can be recycled by an effective means, it will be advantageous in reducing the amount of discarded industrial waste.

[0007] The present invention has been completed based on the above viewpoints, and in one embodiment, it is an object of the present invention to provide an incineration method capable of efficiently incinerating synthetic wood. In another embodiment, it is an object of the present invention to provide a recycling method that efficiently incinerates synthetic wood and is suitable for the composition of the incineration residue. [Means for solving the problem]

[0008] As a result of intensive research, the inventors have found that the synthetic wood can be efficiently incinerated by cutting the synthetic wood into pieces of a predetermined size or less and then incinerating it in a rotary kiln under predetermined conditions, thereby solving the above-mentioned problems. The present invention has been completed based on the above findings, and is exemplified below.

[0009] [1] A method for incinerating synthetic wood having a maximum dimension exceeding 1.5 m, the method comprising the steps of: A first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less; A second step of feeding the pieces into a rotary kiln and incinerating them at a temperature of 800°C to 1200°C for 0.5 hours to 1.5 hours to obtain an incineration residue containing a glass fiber material. wherein the ignition loss of the incineration residue is less than 10%. [2] The incineration method according to [1], characterized in that the pieces are put into a rotary kiln together with industrial waste containing at least waste alkali. [3] The incineration method according to [1] or [2], wherein the incineration residue contains 40 mass% or more of silicon dioxide in terms of oxide. [4] The incineration method according to any one of [1] to [3], wherein the chromium content in the incineration residue is 0.15 mass % or less. [5] The incineration method according to any one of [1] to [4], characterized in that after the first step, the pieces are stored in a flammable storage container, and in the second step, the pieces are loaded into a rotary kiln for each storage container. [6] The incineration method according to [5], wherein in the first step, the synthetic wood is cut while being transported on a conveyor, and the pieces are stored in the storage container installed at the end of the conveyor. [7] The incineration method according to [6], wherein the synthetic wood is cut in only one direction. [8] The incineration method according to any one of [1] to [7], wherein the synthetic wood is a synthetic sleeper. [9] The incineration method according to [8], wherein the synthetic sleepers have a length of 2.5 m to 5.0 m, a width of 0.1 m to 0.4 m, and a thickness of 0.1 m to 0.4 m.

[10] The incineration method according to any one of [1] to [9], wherein in the first step, the synthetic wood is cut into pieces having a maximum dimension of 0.6 m or less.

[11] A method for recycling synthetic wood having a maximum dimension exceeding 1.5m, comprising the steps of: The method comprises: A first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less; A second step of feeding the slices into a rotary kiln and incinerating them at a temperature of 800°C to 1200°C for 0.5 hours to 1.5 hours to obtain an incineration residue containing a glass fiber material; At least a portion of the incineration residue is used as a solvent for slag; The recycling method according to claim 1, wherein the incineration residue contains 40 mass % or more of silicon dioxide calculated as an oxide.

[12] A method for recycling synthetic wood having a maximum dimension exceeding 1.5m, comprising the steps of: The method comprises: A first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less; A second step of feeding the slices into a rotary kiln and incinerating them at a temperature of 800°C to 1200°C for 0.5 hours to 1.5 hours to obtain an incineration residue containing a glass fiber material; At least a part of the incineration residue is used as a raw material for cement, The recycling method according to claim 1, wherein the incineration residue contains 40 mass % or more of silicon dioxide calculated as an oxide.

[13] The recycling method according to

[11] or

[12] , characterized in that the pieces are put into a rotary kiln together with industrial waste containing at least a waste alkali.

[14] The recycling method according to any one of

[11] to

[13] , wherein the chromium content in the incineration residue is 0.15 mass % or less.

[15] The recycling method according to any one of

[11] to

[14] , characterized in that after the first step, the pieces are stored in a flammable storage container, and in the second step, the pieces are loaded into a rotary kiln for each storage container.

[16] The recycling method according to

[15] , wherein in the first step, the synthetic wood is cut while being transported on a conveyor, and the pieces are stored in the storage container installed at the end of the conveyor.

[17] The recycling method according to

[16] , wherein the synthetic wood is cut in only one direction.

[18] The recycling method according to any one of

[11] to

[17] , wherein the synthetic wood is a synthetic sleeper.

[19] The recycling method according to

[18] , wherein the dimensions of the synthetic sleepers are a length of 2.5 m to 5.0 m, a width of 0.1 m to 0.4 m, and a thickness of 0.1 m to 0.4 m.

[20] The recycling method according to any one of

[11] to

[19] , wherein in the first step, the synthetic wood is cut into pieces having a maximum dimension of 0.6 m or less. [twenty one] A method for producing the incineration residue by carrying out the incineration treatment method according to any one of [1] to

[10] . [twenty two] A method for producing a solvent for the slag, comprising carrying out the recycling method according to

[11] or any one of

[13] to

[20] dependent on

[11] . [twenty three]

[12] or a method for producing a raw material for cement, comprising carrying out the recycling method according to any one of

[13] to

[20] dependent on

[12] . Effect of the Invention

[0010] According to one embodiment of the present invention, it is possible to provide an incineration method capable of efficiently incinerating synthetic wood. Also, according to another embodiment of the present invention, it is possible to provide a recycling method that efficiently incinerates synthetic wood and is suitable for the composition of the incineration residue. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a photograph showing an example of synthetic wood. [Diagram 2] FIG. 2 is a photograph showing cut synthetic wood being placed in a flammable container. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the structure of a rotary kiln. [Figure 4] FIG. 4 is a photograph showing an example of incineration residue of synthetic wood. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present invention will be described in detail. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes, improvements, etc. may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0013] (1.Synthetic wood) The synthetic wood that is the subject of the incineration and recycling method of the present invention is a synthetic wood containing fiber-reinforced plastic containing glass fiber material and having a maximum dimension exceeding 1.5 m. The maximum dimension refers to the longest dimension among the dimensions in any direction. Typically, the synthetic wood is a synthetic sleeper for a railway. The dimensions of the synthetic sleeper vary depending on the application, but the typical dimensions of the synthetic sleeper are in the range of 2.5 m to 5.0 m in length, 0.1 m to 0.4 m in width, and 0.1 m to 0.4 m in thickness. As described later, since the synthetic sleeper is long, it is necessary to cut it in the length direction at least once in order to incinerate it sufficiently, but it is also possible to incinerate it without cutting it in the width direction and thickness direction. Figure 1 is a photograph showing an example of synthetic wood. In this example, the synthetic wood is a synthetic sleeper with a length of 2700 mm, a width of 230 mm, and a thickness of 150 mm, and is bundled together.

[0014] Synthetic wood contains synthetic resin and glass fiber material. Synthetic wood contains, for example, 40% or more synthetic resin. Examples of synthetic resin include epoxy resin and rigid foamed urethane resin such as polymethylene polyphenyl polyisocyanate polyol compound. The glass fiber material in synthetic wood preferably contains 40% or more by mass of silicon dioxide in oxide equivalent. There is no particular upper limit to the amount of silicon contained in the glass fiber material in synthetic wood, but it may contain, for example, 60% or less by mass of silicon dioxide in oxide equivalent. The amount of silicon dioxide contained in the glass fiber material in synthetic wood is measured from the incineration residue obtained by incineration by the incineration treatment method of the present invention, as described later. Examples of glass fiber materials suitable for use in synthetic wood include long fiber glass such as alkali-free glass (E glass, S glass) and alkali-containing glass (C glass, D glass).

[0015] (2. Method of incineration of synthetic wood) In one embodiment, the incineration method for synthetic wood of the present invention includes a first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less. As described above, the synthetic sleepers are long, such as 2.5 m to 5.0 m in length, and therefore there is a problem that the workability is poor if they are put into a rotary kiln as they are. In addition, it is possible to store the synthetic sleepers in a flammable container and transport them before putting them into the rotary kiln, but it may be difficult to store them in the container in their original shape, and transportation may be difficult. Therefore, it is necessary to cut the synthetic wood into pieces with a maximum dimension of 1.5 m or less, preferably 1.0 m or less, and more preferably 0.6 m or less. Since the synthetic sleepers are long, it is desirable to cut them into shorter lengths.

[0016] From the viewpoint of sufficiently burning the organic components of the synthetic resin, it is preferable to cut the synthetic wood into pieces of shorter length, but cutting into pieces of excessively short length increases the number of times the synthetic wood is cut in the first step, which is not preferable in terms of work efficiency. Therefore, the synthetic wood may be cut into pieces of a maximum dimension of 0.1 m or more, preferably 0.3 m or more.

[0017] Since the dimensions of synthetic sleepers in the width and thickness directions are relatively small, they can be incinerated without being cut in the width and thickness directions. However, smaller pieces are preferable from the viewpoint of sufficiently burning the organic components of the synthetic sleepers. For this reason, the pieces of synthetic sleepers can be further cut in half, thirds, etc. along the width or thickness direction.

[0018] As mentioned above, it is possible to store the synthetic wood chips in a combustible storage container. In the second step described below, the synthetic wood chips can be fed into the rotary kiln for each combustible storage container. This can eliminate the need to transport and feed the chips individually, improving work efficiency. A typical example of a combustible storage container is a flexible container bag.

[0019] In order to store the pieces of synthetic wood in a flammable storage container, preferably, in the first step, the synthetic wood is cut while being conveyed on a conveyor, and the pieces are stored in a storage container installed at the end of the conveyor. The synthetic wood is preferably conveyed along its longitudinal direction. In this case, the synthetic wood can be cut by a saw arranged perpendicular to its longitudinal direction, but in this case, it is preferable that the synthetic wood is cut in only one direction. That is, it is not necessary to turn over the synthetic wood or the equipment while cutting the synthetic wood while conveying it on the conveyor. In one example, a flexible container bag is installed at the end of the conveyor in an open state, and a saw for cutting the synthetic wood is arranged perpendicular to the conveyor conveyor direction (i.e., the longitudinal direction of the synthetic wood). FIG. 2 shows a photograph of the synthetic wood after cutting by the equipment and stored in the flexible container bag.

[0020] Next, the pieces obtained by cutting are put into a rotary kiln and incinerated at a temperature of 800°C to 1200°C for 0.5 to 1.5 hours in the second step. The thermal decomposition temperature of the synthetic resin contained in the synthetic wood is usually lower than 800°C (for example, the thermal decomposition temperature of epoxy resin is 250°C to 350°C), but when incinerating industrial waste, a temperature of 800°C or higher is usually required to decompose dioxins. In addition, synthetic wood often contains glass fiber material as a reinforcing material, and when the synthetic wood is incinerated to remove the organic matter, the glass fiber material remains. Each fiber of the glass fiber material is a thin fiber with a sharp tip that easily scatters, which causes a problem of poor work safety. Therefore, when incinerated at a temperature of 800°C or higher, at least a part of the glass fiber material melts and solidifies, so that even if it scatters, the glass fiber material will not scatter in the form of a fiber with a sharp tip, improving work safety. On the other hand, even if the incineration temperature exceeds 1200°C, the effect will plateau, so the upper limit is set to 1200°C from the viewpoint of productivity and cost. The upper limit of the incineration temperature can also be set to 1100°C or lower, or 1000°C or lower. When a secondary combustion furnace is connected downstream of the rotary kiln, the incineration temperature means the exhaust temperature measured at the exhaust port of the secondary combustion furnace, and when a secondary combustion furnace is not connected, the incineration temperature means the exhaust temperature measured at the exhaust port of the rotary kiln.

[0021] Also, the synthetic wood chips obtained by cutting may be fed into the rotary kiln alone, but in a preferred embodiment of the present invention, the chips may be fed into the rotary kiln together with industrial waste containing at least waste alkali. As long as the above-mentioned incineration temperature conditions are met, there is no problem in incinerating the synthetic wood chips together with other industrial waste in the rotary kiln. In particular, when waste alkali is incinerated, oxides such as SiO2, CaO, Al2O3, and Fe2O3 are formed, and these oxides can be used as raw materials for cement, so it is desirable that the industrial waste to be treated together with the synthetic wood contains waste alkali.

[0022] If the incineration time is less than 0.5 hours, the organic matter in the synthetic wood cannot be sufficiently burned, and the ignition loss described below cannot be achieved. On the other hand, if the incineration time exceeds 1.5 hours, the effect will reach a plateau, so the upper limit is set to 1.5 hours from the viewpoint of productivity and cost. The upper limit of the incineration time can also be set to 1 hour or less.

[0023] A rotary kiln is used for the incineration in the second step. The specific configuration of the rotary kiln is not limited. A typical rotary kiln has a substantially cylindrical shape, and the inner wall is fireproofed. FIG. 3 is a schematic diagram showing an example of the structure of a rotary kiln. As shown in FIG. 3, the rotary kiln 10 has a cylindrical portion 10d extending substantially in the left-right direction of the paper, and a burner 10a is provided. A lifter for stirring the incineration material is installed on the inner wall of the cylindrical portion 10d, and the incineration material is crushed by stirring by the lifter, promoting incineration. During the incineration process, air is introduced into the cylindrical portion 10d, and in some cases, fuel oil is added. Cut pieces of synthetic wood, etc. are added as input materials through the opening 10b of the cylindrical portion 10d. The cylindrical portion 10d of the rotary kiln 10 rotates around the central axis in the longitudinal direction as the rotation axis, so that the input materials are incinerated while being stirred by the lifter in the cylindrical portion 10d. Cinders (incinerated residue) are discharged from a discharge chute 10e. Gases generated by the incineration of the materials are discharged from an exhaust port 10c. The discharged gases can be sent to an exhaust gas treatment facility such as a secondary combustion furnace 20. The incineration temperature is measured at the exhaust port of the secondary combustion furnace 20.

[0024] In addition to synthetic wood, other industrial waste that is usually incinerated in a rotary kiln can also be fed into the rotary kiln. The mixing ratio of synthetic wood to other industrial waste is not particularly limited, and can be fed at any ratio as needed. The other industrial waste can include sludge, waste plastic, waste oil, waste alkali, waste acid, etc., in addition to the above-mentioned waste alkali. An example of the sludge is tank sludge. These incineration residues can be crushed and sieved as appropriate and used as raw materials for cement.

[0025] The second step produces an incineration residue containing a glass fiber material. The incineration residue can be disposed of as industrial waste or reused, for example, as a slag solvent as described below. To dispose of the incineration residue as industrial waste, the ignition loss of the incineration residue must be less than 10%. There is no need to set a lower limit for the ignition loss, but an appropriate lower limit for actual operation may be set, for example, to 4.0% or more. In addition, the incineration residue can be used as a slag solvent or a raw material for cement as described below. Therefore, in another aspect, the present invention discloses a method for producing an incineration residue.

[0026] Ignition loss (or ignition loss) is measured according to the method described in Attachment 2 of "Points to Note in Guidance for General Waste Treatment Businesses" (Ensei No. 95), issued on November 4, 1977. Specifically, the incineration residue is thoroughly dried at 105°C ± 5°C using a dryer or similar device, and then ignited in an electric furnace at 600°C ± 25°C for three hours. The weight loss rate of the incineration residue after these operations is defined as the ignition loss.

[0027] (3. How to recycle synthetic wood) One embodiment of the synthetic wood recycling method of the present invention includes using at least a part of the incineration residue obtained by any of the embodiments of the synthetic wood incineration method of the present invention as a slag solvent. In other words, one embodiment of the present invention is the use of the incineration residue obtained by any of the embodiments of the synthetic wood incineration method of the present invention as a slag solvent, and a method for producing the slag solvent is disclosed.

[0028] Slag refers to a mixture that is generated by the action of a solvent when melting and refining industrial waste, ores, etc. For example, when processing industrial waste such as incineration ash containing metallic iron, sludge, slag, printed circuit boards, pad scraps, waste catalysts, metal scraps, waste shot, grinding chips, and dust, there is a method of melting industrial waste in which the industrial waste is put into the melting hearth of a reverberatory furnace-type recycling furnace, and the resulting molten material is poured into a basin and separated into slag and matte.

[0029] In order to efficiently separate the slag and matte obtained by the above melting process, it is necessary to melt the high melting point melt into a low melting point slag. For example, iron oxide (Fe 3+ Slag with a high iron content can be converted into metallic iron slag by the following reaction: Fe+Fe2O3→3FeO 2FeO+SiO2 → 2FeO SiO2

[0030] Therefore, a SiO2 source is needed as a flux to lower the melting point of the slag in the recycle furnace.

[0031] In addition to the above-mentioned recycling furnaces for the treatment of industrial waste, non-ferrous smelting furnaces also require a SiO2 source as a slag solvent. For example, copper smelting furnaces include flash furnaces, which oxidize copper concentrate to produce copper matte with a copper content of about 65% and slag mainly composed of Fe and Si, and converters, which oxidize copper matte to produce blister copper with a copper content of about 99%. In flash furnaces and converters, the raw materials are kept in a molten state by the heat of the oxidation reaction, and are separated into two phases, copper matte and slag, or blister copper and slag, which are then recovered. A solvent is added to the slag to obtain an appropriate composition and to lower the melting point during melting.

[0032] There are various types of fluxes for copper smelting, but silica ore, which is mainly composed of SiO2, is commonly used. When silica ore is used as a flux, the following reaction occurs in the flash furnace or converter. Flash furnace: CuFeS2+SiO2+O2→Cu2S·FeS+2FeO·SiO2+SO2 Converter:Cu2S·FeS+SiO2+O2→Cu+2FeO·SiO2+SO2

[0033] There are various types of glass fiber materials contained in synthetic wood, but glass fiber materials mainly composed of silicon-based oxides are common. Silicon-based oxides refer to inorganic oxides that contain silicon. Therefore, the incineration residue of synthetic wood can be used as a SiO2 source for the slag solvent in recycling furnaces and copper smelting furnaces. In addition, by supplying the incineration residue of synthetic wood to flash smelting furnaces, which have a large amount of copper concentrate processed and require a larger SiO2 source, a larger amount of processing can be expected.

[0034] However, since the glass fiber material contained in synthetic wood may contain Al in the form of alumina, it also contains components that are unnecessary as a SiO2 source for slag. Therefore, it is preferable to mix the synthetic wood incineration residue with other SiO2 sources before supplying it to a recycling furnace or a non-ferrous smelting furnace. By thoroughly mixing the synthetic wood incineration residue with other SiO2 sources, it is possible to avoid sudden fluctuations in the components and form a stable slag. However, if the volume of the synthetic wood incineration residue is small and the effect on the components of the solvent in the recycling furnace or non-ferrous smelting furnace is small, it is also possible to supply the incineration residue as it is.

[0035] In addition, when silica ore is used as a SiO2 source for a non-ferrous smelting furnace such as a flash furnace, it is common to crush the silica ore with a crushing device before feeding it into the non-ferrous smelting furnace, but it is also preferable to crush the synthetic wood incineration residue before feeding it. This makes it possible to further homogenize the components.

[0036] Another embodiment of the synthetic wood recycling method of the present invention includes using at least a part of the incineration residue obtained by any of the embodiments of the synthetic wood incineration method of the present invention as a raw material for cement. In other words, one embodiment of the present invention is the use of the incineration residue obtained by any of the embodiments of the synthetic wood incineration method of the present invention as a raw material for cement, and a method for producing the raw material for cement is disclosed.

[0037] The raw materials for cement include limestone raw materials, which are mainly composed of calcium carbonate, clay raw materials, which are mainly composed of silicon dioxide and aluminum oxide (alumina), silica raw materials, which are mainly composed of silicon dioxide, and iron oxide raw materials. Impurities that may be contained in the raw materials for cement include chlorine, chromium, and other heavy metals (copper, lead, etc.), and it is preferable for these impurities to be low. The raw materials for cement are generally fired at a maximum of 1450°C in a firing furnace such as a kiln to become clinker, which is then cooled, crushed, and other finishing processes to become cement.

[0038] On the other hand, as described later, the incineration residue of synthetic wood is rich in calcium, silicon, and aluminum, but the amount of the above impurity elements is small or almost none. Therefore, if the incineration residue is mixed with other conventional cement raw materials and then burned, it is possible to obtain clinker of a predetermined composition. In particular, since synthetic wood contains almost no chromium, the chromium content in the entire incineration residue can be reduced by incinerating it together with other industrial waste. In one embodiment, the chromium content in the incineration residue is 0.15 mass% or less, preferably 0.10 mass% or less. Therefore, the incineration residue of synthetic wood can be suitably used as a raw material for cement. In that case, it is possible to mix the incineration residue of synthetic wood with other raw materials having a low chromium content to further reduce the overall chromium content. An example of a raw material having a low chromium content is a neutralized precipitate obtained by neutralizing waste sulfuric acid or waste hydrochloric acid with a slaked lime solution. In such a neutralized precipitate, iron and calcium are the main components, and since it contains almost no chromium, a chromium dilution effect can be obtained. EXAMPLES

[0039] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0040] (1. Combustion experiment in a stationary furnace) First, the following experiment was conducted to investigate the composition of the incineration residue when synthetic wood was burned alone without being mixed with other industrial waste.

[0041] A synthetic sleeper with dimensions of 2600 mm length × 200 mm width × 200 mm thickness was prepared. The composition of the synthetic sleeper was glass fiber reinforced urethane foam with 50 mass% alumina borosilicate glass (E glass) and 50 mass% polymethylene polyphenyl polyisocyanate-polyol compound.

[0042] The synthetic sleeper was cut in the center of its length to make a piece of 1300mm length, and the volume was 25.8m 3 The samples were placed in a fixed bed furnace and incinerated for 4 hours. The temperature inside the furnace during incineration was controlled within the range of 850℃ to 900℃.

[0043] The same synthetic sleepers were also prepared and the above procedure was repeated. Since the pieces of the synthetic sleepers were long, the incineration residue was also long. After each test, 100g samples (samples 1 and 2 for the first test, samples 3 and 4 for the second test) were taken from the center of the incineration residue in the length direction, near the center in the thickness direction, and near the surface, and the elemental composition was identified by ICP atomic emission spectrometry (ICP-AES). The measuring device was SPS3520UV manufactured by Hitachi High-Tech Science Co., Ltd., and the measurements were performed in accordance with JIS M8206:2014. In addition, the two samples were combined into one sample and the ignition loss was measured using the above-mentioned method, and the measured value was taken as the ignition loss of the entire incineration residue obtained by each test. The results are shown in Table 1.

[0044] [Table 1]

[0045] As can be seen from Table 1, by incinerating synthetic sleepers under specified conditions, it was possible to obtain an ignition loss of less than 10%. In addition, the amount of Si element in the incineration residue was about 60 mass% in oxide conversion, so it was found that it can be used as a slag solvent. In addition to Si, the amount of Al element was about 14 mass% in oxide conversion, and the amount of Ca element was also about 23 mass% in oxide conversion, so the total amount of these three elements in oxide conversion was close to 100 mass%, and the amount of Cr, which is considered an impurity, was very small, so it was found that it can be used suitably as a raw material for cement.

[0046] (2. Rotary kiln incineration test) Several synthetic sleepers with dimensions of 2700 mm length × 230 mm width × 150 mm thickness were prepared. The composition of the synthetic sleepers was glass fiber reinforced urethane foam with 50 mass% alumina borosilicate glass (E glass) and 50 mass% polymethylene polyphenyl polyisocyanate-polyol compound.

[0047] The synthetic sleepers were cut lengthwise, with each piece measuring 500 mm long x 230 mm wide x 150 mm thick. When these pieces were fed into a rotary kiln, it was confirmed that several pieces weighing a total of 323 kg could be incinerated in about 15 minutes, several pieces weighing a total of 207 kg could be incinerated in about 10 minutes, and several pieces weighing a total of 190 kg could be incinerated in about 10 minutes. The exhaust temperature during incineration was controlled within the range of 800°C to 900°C.

[0048] The above incineration test was conducted twice, and 100g samples were taken from the incineration residue discharged from the rotary kiln, and the elemental composition was identified by inductively coupled plasma atomic emission spectrometry (ICP-AES). The measurement equipment was SPS3520UV manufactured by Hitachi High-Tech Science Corporation, and the measurements were performed in accordance with JIS M8206:2014. In addition, the ignition loss was measured using the above-mentioned method, and the measured value was the ignition loss of the entire incineration residue. Note that since industrial waste including sludge was also fed into the rotary kiln, the above measured value was the value measured for the incineration residue including not only synthetic sleepers but also other incineration materials. The results are shown in Table 2.

[0049] [Table 2]

[0050] As can be seen from Table 2, by incinerating synthetic sleepers under the specified conditions, it was possible to obtain an ignition loss of less than 10%. The amount of Si element in the incineration residue is lower than that in the combustion experiment in a stationary furnace, but it can still be used as a slag solvent. In addition, the amount of chromium, which is considered an impurity, in the incineration residue is higher than that in the combustion experiment in a stationary furnace, but this is thought to be due to the fact that the incineration materials other than synthetic wood contain more chromium. In other words, by incinerating synthetic wood together, it is possible to reduce the chromium content in the entire incineration residue. Therefore, the incineration residue can be suitably used as a raw material for cement. [Explanation of symbols]

[0051] 10 Rotary Kiln 10a Burner 10b opening 10c Exhaust port 10d Cylindrical section 10e Ejection Chute 20 Secondary Combustion Furnace

Claims

1. A method for incinerating synthetic wood having a maximum dimension exceeding 1.5 m, the method comprising the steps of: A first step of cutting the synthetic wood into pieces with a maximum dimension of 1.5 m or less; A second step of feeding the pieces into a rotary kiln and incinerating them at a temperature of 800° C. to 1200° C. for 0.5 to 1.5 hours to obtain an incineration residue containing glass fiber material; wherein the ignition loss of the incineration residue is less than 10%.

2. 2. The incineration method according to claim 1, wherein the cuttings are charged into a rotary kiln together with industrial waste containing at least a waste alkali.

3. The incineration method according to claim 1, wherein the incineration residue contains 40 mass% or more of silicon dioxide in terms of oxide.

4. The incineration method according to claim 1, wherein the chromium content in the incineration residue is 0.15 mass% or less.

5. 2. The incineration method according to claim 1, characterized in that after the first step, the pieces are stored in a combustible storage container, and in the second step, the pieces are loaded into a rotary kiln for each storage container.

6. 2. The incineration method according to claim 1, wherein the synthetic wood is a synthetic railroad tie.

7. The incineration method according to claim 6, wherein the synthetic sleepers have a length of 2.5 m to 5.0 m, a width of 0.1 m to 0.4 m, and a thickness of 0.1 m to 0.4 m.

8. 2. The incineration method according to claim 1, wherein in the first step, the synthetic wood is cut to a maximum dimension of 0.6 m or less.

9. At least a part of the incineration residue obtained by the incineration treatment method according to claim 1 or 2 is used as a solvent for slag, The recycling method according to claim 1, wherein the incineration residue contains 40 mass % or more of silicon dioxide calculated as an oxide.

10. At least a part of the incineration residue obtained by the incineration treatment method according to claim 1 or 2 is used as a raw material for cement, The recycling method according to claim 1, wherein the incineration residue contains 40 mass % or more of silicon dioxide calculated as an oxide.

11. A method for producing the incineration residue by carrying out the incineration treatment method according to claim 1 or 2.

12. 10. A method for producing a solvent for said slag by carrying out the recycling method according to claim 9.

13. 11. A method for producing raw materials for cement, comprising carrying out the recycling method according to claim 10.

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