Ash extrusion device and ash extrusion method

Abstract

To provide an ash pushing device and an ash pushing method which can be achieved by improvement of an existing stoker type incineration facility without any need for an additional large scale device, suppress an increment of energy to be used, and can recover valuable metals.SOLUTION: An ash pushing device includes a water storage part 10 for receiving a main ash discharged from a stoker type incinerator and cooling the main ash with water, a chute 40 which is provided on one end side of the water storage part and discharges the cooled hydrous main ash, an inclination part 20 which is provided from the water storage part to the chute so as to be inclined upward, and a pusher 30 for pushing the main ash charged into the water storage part toward the chute, and can recover the main ash while segregating it into valuable metal high-concentration ash and valuable metal low-concentration ash.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an ash extrusion device and an ash extrusion method that can recover valuable metals from the bottom ash of a stoker-type incinerator, and in particular to a wet ash extrusion device and an ash extrusion method that do not require any large-scale additional processing equipment and that use only a small amount of energy. [Background technology]

[0002] In waste incineration facilities, miscellaneous waste is incinerated, but disposal of the cinders generated by such incineration is a problem, and there is a demand for reducing the cinders and recycling them. Therefore, various technologies have been proposed to recover resources (e.g., valuable metals) from the cinders and recycle them.

[0003] For example, Patent Document 1 discloses a metal smelting raw material recovery device that recovers metal smelting raw materials from incineration ash discharged from a grate-type waste incinerator. As shown in Figure 2 of Patent Document 1, a technology for recovering valuable metals from falling ash is proposed by switching between a falling ash supply operation in which falling ash falling from the gaps in the grate and the combustion air outlets of the grate is collected by a falling ash collector and then sent to a waste gasification and melting apparatus, and a bottom ash supply operation in which bottom ash discharged from the end of the grate is collected by a bottom ash collector and then sent to the waste gasification and melting apparatus. Patent Document 1 also describes a method in which, because the amount of valuable metals in the bottom ash is small and their recovery is difficult, the bottom ash and falling ash are separated and recovered, and each is melted separately in a waste gasification and melting apparatus to recover the valuable metals.

[0004] Patent Document 2 proposes a method for recovering precious metals from incineration ash, which includes a crushing process in which incineration ash containing precious metal-adhered particles, to produce precious metal-enriched particles containing precious metals scraped off the surfaces of the precious metal-adhered particles in the incineration ash, and other particles; a classification process in which the precious metal-enriched particles obtained in the crushing process and other particles are separated into particles of a certain particle size; a gravity separation process in which the particles classified in the classification process are gravity-separated to separate the precious metal-enriched particles from the other particles; and a high-force magnetic separation process in which magnetically attracted metals contained in the heavy ash containing the precious metal-enriched particles are separated using a magnetic field. The classification process is performed by sieving, and the gravity separation process is a dry process in which the incineration ash on an air table is floated by blown-up airflow and suction airflow, while vibration is used to form a fluidized bed in which the high-specific-gravity granular ash is in the lower layer and the low-specific-gravity light ash is in the upper layer.

[0005] Patent Document 3 proposes a valuable metal recovery system in which incineration ash is dried, magnetic metals are removed by magnetic separation, then sieved and classified, and non-magnetic metal particles that have adhered to the magnetic metals and are smaller than the original specified particle size are recovered by magnetic separation and eddy current separation again, and the resulting material is crushed in a vertical mill, dried and classified into fine powder (mill refined powder) and coarse powder (mill waste), and the valuable metals are concentrated in the mill waste and recovered.

[0006] In Patent Document 4, the ratio of the area of ​​the combustion air nozzle to the total area of ​​the grate hearth is 2%. Patent Document 4 discloses a method and device for recovering metals from waste incineration ash, which uses a grate with a porosity of 5% or less to separate and collect falling ash that falls from the gaps in the grate and the combustion air outlets and bottom ash that is discharged from the end of the grate, and recovers valuable metals from the separated and collected falling ash. Patent Document 4 describes that valuable metals are contained in greater amounts in falling ash than in bottom ash, and that when the grate porosity is less than 2%, most of the valuable metals are contained in the bottom ash. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6391046 [Patent Document 2] Patent No. 6465825 [Patent Document 3] Patent No. 6375205 [Patent Document 4] Patent No. 3661662 Summary of the Invention [Problem to be solved by the invention]

[0008] In the technology described in Patent Document 1, the bottom ash separated from the dust ash is sent directly to a downstream waste gasification and melting device and treated together with the waste. Although valuable metals are contained in large amounts in the dust ash, the total amount of dust ash in a stoker-type incinerator is small compared to the total amount of bottom ash, and the amount of valuable metals that can be recovered from the entire waste is small. Furthermore, because the bottom ash with a high moisture content is melted directly together with the waste in the waste gasification and melting device, drying equipment, wastewater treatment equipment, etc. are required, resulting in a problem of a low recovery rate of valuable metals compared to the high energy consumption.

[0009] The techniques described in Patent Documents 2 and 3 are both dry processes that use both sieve classification and magnetic separation, and therefore require large-scale and complicated equipment configurations.

[0010] The technology described in Patent Document 4 uses a grate with a specific grate porosity range to recover valuable metals from falling ash that falls through the gaps in the grate, but does not recover valuable metals from the bottom ash. If the grate porosity deviates from the specific range, valuable metals will be contained in the bottom ash, making it impossible to recover valuable metals from the incineration ash.

[0011] Therefore, the object of the present invention is to provide an ash extrusion device and an ash extrusion method that can be realized by simply improving an existing stoker-type incineration facility without requiring any large-scale additional equipment, and that can recover valuable metals while suppressing the increase in energy used. [Means for solving the problem]

[0012] The inventors have conducted extensive research to solve the above problems, and have completed the present invention, which enables valuable metals to be recovered at low cost by forming highly concentrated valuable metal ash, in which the valuable metals in the bottom ash are concentrated in the water storage section of an existing incineration facility, and low concentrated valuable metal ash, which has a low content of valuable metals, and then separating and recovering these.

[0013] The present invention provides the following aspects. [1] A water storage section that receives and cools the bottom ash discharged from the stoker-type incinerator; a chute provided at one end of the water storage section for discharging the cooled moist bottom ash; an inclined portion inclined upward from the water storage portion to the chute; a pusher that pushes the bottom ash introduced into the water storage section toward the inclined section; An ash extrusion device for a stoker-type incinerator, comprising: The inclined portion is a first inclined surface provided so as to incline upward from the bottom surface of the water storage portion; a partition that forms a second inclined surface at a position above the first inclined surface, at least on the tip side of the first inclined surface; the second inclined surface extends beyond the tip of the first inclined surface; The partition defines a first water-containing bottom ash transport path on the first inclined surface and a second water-containing bottom ash transport path on the second inclined surface, The shot in question was a first chute that receives the first moist bottom ash dropping from the first moist bottom ash conveying path; A second chute that receives the second water-containing bottom ash dropping from the second water-containing bottom ash conveying path. An ash extrusion device for a stoker-type incinerator. [2] The ash extrusion device described in [1] above is characterized in that a baffle plate is provided between the first chute and the second chute, and is erected above the height position of the tip of the first inclined surface. [3] The ash extrusion device described in [1] or [2] above, characterized in that the extrusion surface located at the tip of the pusher has, at least in part, an inclined portion formed so as to protrude in the forward direction of the pusher. [4] The pusher is capable of reciprocating multiple times from the backward limit position of its extrusion surface with a stroke length of half a stroke or less, thereby flowing and stirring the bottom ash and water fed into the water storage section to produce moist bottom ash; the extrusion surface can be stopped for a predetermined time, and the extrusion surface can be operated at its full stroke length from the backward limit position to the forward limit position to compress and transport the moist bottom ash to the inclined section, thereby causing relatively small particles or relatively heavy components in the moist bottom ash to settle and relatively large particles and light components to float, thereby forming a first moist bottom ash and a second moist bottom ash having different contents of valuable metals. [5] An ash extrusion method for separating and recovering bottom ash in a stoker-type incineration facility equipped with an ash extrusion device according to any one of [1] to [4] above, a stirring and mixing process in which the bottom ash fed from the stoker-type incinerator to the water storage section is stirred and mixed by a pusher with multiple reciprocating motions of less than half the stroke length to form moist bottom ash; and a resting process in which the pusher is stopped for a predetermined time to allow relatively small particles or heavy components in the moist bottom ash to settle and relatively large light components to float. a compressing and conveying step of compressing and conveying the water-containing bottom ash to an inclined portion by advancing the pusher through its entire stroke length, The stirring and mixing step, the stationary step, and the compressing and conveying step are repeated a plurality of times to compress and convey the wet bottom ash upward along the inclined portion to a chute, thereby forming a first wet bottom ash and a second wet bottom ash having different concentrations of valuable metals; The first moist bottom ash is dropped into a first chute, and the second moist bottom ash is dropped into a second chute, and the moist bottom ashes with different concentrations of valuable metals are separated and collected. The ash extrusion method is characterized by the above. [6] The ash extrusion method described in [5] above, wherein the first hydrated bottom ash is a valuable metal-rich bottom ash having a relatively high concentration of valuable metals, and the second hydrated bottom ash is a valuable metal-rich bottom ash having a relatively low concentration of organic metals. [Effects of the Invention]

[0014] The ash extrusion device and ash extrusion method of the present invention can concentrate and separate valuable metals in bottom ash simply by improving the water storage section and chute of an existing stoker-type incinerator. This eliminates the need for special equipment, such as wastewater treatment equipment and drying equipment, required for conventional wet concentration. Furthermore, there is little increase in the energy required for water treatment, in addition to the energy required for existing equipment used to cool and moisten the bottom ash. Conventionally, only small amounts of valuable metals could be recovered because the ash falling from the grate of a stoker-type incinerator was treated. However, the present invention treats the large amount of bottom ash generated, thereby increasing the amount of valuable metals that can be recovered. The ash extrusion device and ash extrusion method of the present invention are useful as pretreatment for valuable metal recovery equipment, such as existing ash melting equipment and ecocement equipment. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic explanatory diagram showing the overall configuration of a stoker-type incinerator and an ash extrusion device. [Figure 2] Figure 2(b) is a schematic explanatory diagram showing a first embodiment of the ash extrusion device of the present invention, where Figure 2(a) is a top perspective view of Figure 2(b), and Figure 2(c) is a cross-sectional view taken along line AA of Figure 2(b). [Figure 3] Figure 3(b) is a schematic explanatory diagram showing a second embodiment of the ash extrusion device of the present invention, where Figure 3(a) is a top perspective view of Figure 3(b), and Figure 3(c) is a cross-sectional view taken along line AA of Figure 3(b). [Figure 4] FIG. 4(b) is a schematic explanatory diagram showing a third embodiment of the ash extrusion device of the present invention, in which FIG. 4(a) is a top perspective view of FIG. 4(b), and FIG. 4(c) is a cross-sectional view taken along line AA of FIG. 4(b). [Figure 5]Figure 5(b) is a schematic explanatory diagram showing a fourth embodiment of the ash extrusion device of the present invention, where Figure 5(a) is a top perspective view of Figure 5(b), and Figure 5(c) is a cross-sectional view taken along line AA of Figure 5(b). [Figure 6] Figure 6(b) is a schematic explanatory diagram showing a fifth embodiment of the ash extrusion device of the present invention, where Figure 6(a) is a top perspective view of Figure 6(b), and Figure 6(c) is a cross-sectional view taken along line AA of Figure 6(b). [Figure 7] Figure 7(b) is a schematic explanatory diagram showing a sixth embodiment of the ash extrusion device of the present invention, where Figure 7(a) is a top perspective view of Figure 7(b), and Figure 7(c) is a cross-sectional view taken along line AA of Figure 7(b). [Figure 8] Figure 8(b) is a schematic explanatory diagram showing a seventh embodiment of the ash extrusion device of the present invention, Figure 8(a) is a top perspective view of Figure 8(b), and Figure 8(c) is a cross-sectional view taken along line AA of Figure 8(b). [Figure 9] FIG. 9(a) is a top view showing a first embodiment of a pusher that can be used in the ash pusher of the present invention, and FIG. 9(b) is a side view of FIG. 9(a). [Figure 10] FIG. 10(a) is a top view showing a second embodiment of a pusher that can be used in the ash pusher of the present invention, and FIG. 10(b) is a side view of FIG. 10(a). [Figure 11] FIG. 11(a) is a top view showing a third embodiment of a pusher that can be used in the ash pusher of the present invention, and FIG. 11(b) is a side view of FIG. 11(a). [Figure 12] FIG. 12(a) is a top view showing a fourth embodiment of a pusher that can be used in the ash pusher of the present invention, and FIG. 12(b) is a side view of FIG. 12(a). [Figure 13] FIG. 13(a) is a top view showing a fifth embodiment of a pusher that can be used in the ash pusher of the present invention, and FIG. 13(b) is a side view of FIG. 13(a). [Figure 14] Figure 14(b) is a schematic explanatory diagram showing a conventional ash extrusion device, where Figure 14(a) is a top perspective view of Figure 14(b), and Figure 14(c) is a cross-sectional view taken along line AA of Figure 14(b). [Explanation of symbols]

[0016] 1. Ash extrusion device 10 Water storage section 20 Slope 21 First Inclined Surface 22 First Guide 23 First water-containing bottom ash transport route (highly concentrated valuable metal ash transport route) 24 Second Guide 25 Partition (second inclined surface) 27 Second water-containing bottom ash transport route (low-concentrated ash transport route for valuable metals) 30 Pusher 33 Extrusion surface 33c Slope 40 shots 43 First chute (discharge outlet for highly concentrated ash containing valuable metals) 45 Second chute (low-concentrated ash discharge outlet for valuable metals) 47 Baffle Plate DETAILED DESCRIPTION OF THE INVENTION

[0017] Preferred embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to these in any way.

[0018] As shown in FIG. 1, the ash extrusion device of the present invention processes bottom ash, which is obtained by incinerating various miscellaneous waste in a stoker-type incinerator and is fed from the end of the fire grate 3 through a bottom ash feed pipe 5 into a water reservoir 10 of the ash extrusion device. A stoker-type incinerator generates more bottom ash than fly ash. Bottom ash contains precious metals such as gold, silver, copper, and platinum, as well as valuable metals such as zinc and lead, although in smaller amounts than those contained in fly ash. In this specification, the precious metals and valuable metals contained in bottom ash are collectively referred to as "valuable metals."

[0019] In the present invention, "highly concentrated valuable metal ash" refers to bottom ash in which valuable metals are concentrated and contained at a relatively high concentration, while "low concentrated valuable metal ash" refers to bottom ash in which valuable metals are not concentrated but contained at a relatively low concentration. "Highly concentrated valuable metal ash" has a concentration of valuable metals that is at least about 1.5 times, preferably at least about 1.7 times, the average concentration of valuable metals in the bottom ash, while "low concentrated valuable metal ash" has a concentration of valuable metals that is at most about 0.7 times, preferably at most about 0.6 times, the average concentration of valuable metals in the bottom ash. "Highly concentrated valuable metal ash" desirably has a concentration of valuable metals that is at least about 2 times, preferably at least about 2.5 times, the concentration of valuable metals in "low concentrated valuable metal ash." For example, if the valuable metal is copper, the highly concentrated valuable metal ash preferably contains at least 10 g / kg of copper.

[0020] [Ash extrusion device] The ash extrusion device 1 for a stoker-type incinerator of the present invention shown in Figures 2 to 8 is an improvement over the conventional ash extrusion device for a stoker-type incinerator shown in Figure 14, and the configuration of the conventional ash extrusion device for a stoker-type incinerator can be used except for the improvements. Here, the improvements will be mainly explained.

[0021] The ash extrusion device for a stoker-type incinerator of the present invention is equipped with a water storage section 10 that receives bottom ash discharged from the stoker-type incinerator and cools it with water, a chute 40 provided at one end of the water storage section for discharging the cooled, wet bottom ash, an inclined section 20 provided sloping upward from the water storage section to the chute, and a pusher 30 that pushes the bottom ash introduced into the water storage section toward the inclined section, and is capable of separating and recovering the bottom ash into ash with a high concentration of valuable metals and ash with a low concentration of valuable metals. This will be described in further detail below.

[0022] [Water storage section] As shown in Fig. 1, the water storage section 10 is configured to store water for cooling bottom ash received from the end of the grate 3 of the stoker-type incinerator via the bottom ash input pipe 5. As shown in Figs. 2 to 8, the top surface of the water storage section 10 has an opening 11 that allows bottom ash to be input from the bottom ash input pipe 5. The bottom of the water storage section 10 is provided with a pusher insertion opening 13 for inserting a pusher 30, and a bottom ash extrusion opening 15 that is located opposite the pusher insertion opening 13 and extrudes the extruded bottom ash toward the inclined section 20. A water level gauge (not shown) may also be installed to monitor the water level in the water storage section 10.

[0023] [Slanted part] The inclined section 20 is a conveying path that slopes upward from the bottom of the water storage section 10 toward the chute 40, and conveys the wet bottom ash that has been introduced into the bottom of the water storage section 10 and cooled, while compressing and dehydrating it with the pusher 30 and pushing it upward toward the chute 40. The inclination angle of the inclined section 20 is not particularly limited as long as it can form a path that allows the wet bottom ash to be compressed and conveyed while being dehydrated, but generally, an angle of 20° to 35° is preferred.

[0024] The inclined portion 20 is a first inclined surface provided inclined upward from the bottom surface of the water storage portion 10. The apparatus has a first inclined surface 21 and a partition 25 forming a second inclined surface that is parallel to the first inclined surface 21 and located above the first inclined surface 21 at least on the tip side of the first inclined surface 21. A first moist bottom ash transport path 23 is defined between the first inclined surface 21 and the partition 25 forming the second inclined surface, and a second moist bottom ash transport path 27 is defined above the partition 25 forming the second inclined surface. Here, the concentrations of valuable metals contained in the first moist bottom ash and the second moist bottom ash are different. When the first moist bottom ash is a highly concentrated valuable metal ash, the second moist bottom ash is a low concentrated valuable metal ash, and when the first moist bottom ash is a low concentrated valuable metal ash, the second moist bottom ash is a highly concentrated valuable metal ash.

[0025] As long as the partition 25 is provided at least on the tip side of the first inclined surface 21, it can separate the wet bottom ash falling into the chute into a first wet bottom ash and a second wet bottom ash. The length of the partition 25 is not particularly limited, and it may be the same length from the base end to the tip of the first inclined surface 21, or the base end of the partition 25 may be positioned closer to the tip end of the first inclined surface 21 than the base end of the first inclined surface 21 and may be shorter than the first inclined surface 21. For example, when the moisture content of the wet bottom ash is higher than about 20%, segregation due to differences in specific gravity is likely to occur, so it is preferable that the base end of the partition 25 is close to the base end of the first inclined surface 21 and that the overall length is long. However, when the moisture content of the wet bottom ash is lower than about 20%, it is preferable that the base end of the partition 25 is close to the tip of the first inclined surface 21 and that the overall length is short in order to effectively cause segregation due to differences in particle size. For example, if the moist bottom ash contains a large amount of non-combustible matter or large foreign matter, these will create resistance when transporting along the inclined section 20, so it is preferable to position the base end of the partition 25 close to the tip of the first inclined surface 21 and shorten the overall length.

[0026] The partition 25 need only be spaced apart and substantially parallel to the first inclined surface 21; it need not be parallel to the upper wall surface of the inclined portion 20. The drawings show a case in which the upper wall surface and the lower wall surface (corresponding to the first inclined surface) of the inclined portion 20 are parallel. In the illustrated configuration, the second wet bottom ash conveying path 27 has the same height from the base end to the tip. However, if the inclination angle of the upper wall surface of the inclined portion 20 is greater than that of the lower wall surface and the path is shaped to widen toward the chute, the partition 25 is substantially parallel to the first inclined surface 21 but not parallel to the upper wall surface of the inclined portion 20. In other words, the second wet bottom ash conveying path 27 may be shaped such that its width is wider from the base end to the tip end. The wider tip end prevents compaction from occurring in the second wet bottom ash conveying path 27, making it less likely to be clogged with wet bottom ash.

[0027] Furthermore, the distance of the partition 25 from the first inclined surface 21 is not limited. For example, the partition 25 can be provided so that the first moist bottom ash conveying path 23 and the second moist bottom ash conveying path 27 have the same height, or so that the height of the first moist bottom ash conveying path 23 is greater or smaller than the height of the second moist bottom ash conveying path 27. For example, when the lower layer of the moist bottom ash conveyed on the inclined section 20 is highly valuable metal-enriched ash, the partition 25 can be provided at a height position of ½ or less, preferably ⅓ or less, of the total height of the inclined section 20.

[0028] The widthwise cross section of the partition 25 may be linear or arch-shaped. Here, a linear cross section means that the inclined portion 20 has a uniformly flat surface across the entire width, and an arch-shaped cross section means that the central portion in the width direction has an uneven surface that protrudes upward or downward. When the cross section is arch-shaped, a concave or convex surface that is approximately parallel to the first inclined surface 20 may be formed in the widthwise central portion, or the partition 25 may be dome-shaped with a concave or convex surface at its apex. The dome-shaped cross section makes it difficult for a compacted state to occur in the first wet bottom ash conveying path 23, and therefore makes it difficult for wet bottom ash to clog the path.

[0029] The longitudinal cross section of the partition 25 may be linear or arch-shaped. Here, a linear cross section means that the inclined portion 20 has a uniformly flat surface over the entire length in the longitudinal direction, and an arch-shaped cross section means that the inclined portion 20 has a substantially parallel surface to the first inclined surface 21 near the base end and near the tip end, but has an uneven surface that protrudes upward or downward in the center of the inclined portion 20. The arch shape makes it difficult for compaction to occur, and therefore it is difficult for plugging to occur due to the water-containing bottom ash.

[0030] [Shoot] The chute 40 is composed of a hollow cylinder connected to the tip of the inclined section 20, and has a first chute 43 that receives the first moist bottom ash falling from the first moist bottom ash conveying path 23, and a second chute 45 that receives the second moist bottom ash falling from the second moist bottom ash conveying path 27. If the first moist bottom ash is a highly concentrated valuable metal ash, the first chute receives the highly concentrated valuable metal ash, and the second chute receives the low concentrated valuable metal ash. If the first moist bottom ash is a low concentrated valuable metal ash, the first chute receives the low concentrated valuable metal ash, and the second chute receives the high concentrated valuable metal ash.

[0031] [Pusher] As shown in Figure 9, the pusher 30 is composed of an arm 31 connected to a drive unit (not shown) and a push surface 33 located at the tip of the arm 31, which pushes the bottom ash introduced into the water storage unit 10 toward the inclined section 20. The arm 31 is driven by a known drive mechanism such as a hydraulic cylinder, similar to that used in conventional pushers. In the ash pusher of the present invention, in addition to forward and backward limits for determining the operating position of the pusher 30, a neutral limit and / or a proportional control solenoid valve are provided. This allows the push surface 33 of the pusher 30 to reciprocate over a full stroke from the base end (pusher side) of the bottom of the water storage unit 10 to the tip (chute side) as well as a half-stroke from the base end to approximately the center of the bottom of the water storage unit 10, and the push surface 33 of the pusher 30 can be stopped at a predetermined position for a predetermined time. That is, the pusher 30 is reciprocated multiple times from its rearmost position (a position closer to the base end of the arm than the pusher insertion port 13) at a stroke length of less than half a stroke (to a position approximately at the center of the water storage section 10) to fluidize and agitate the bottom ash and water introduced into the water storage section 10, separating heavy components such as valuable metals contained in the bottom ash from the bottom ash. The pusher 30 is then stopped at the rearmost position for a predetermined period of time, from several tens of seconds to several minutes, to allow the heavy components to settle downward and the lighter components to float upward, thereby forming a two-layer structure of a lower layer containing a large amount of heavy components and an upper layer containing a large amount of lighter components. After repeating a set of multiple reciprocating movements at the half-stroke length and a predetermined period of stopping at the rearmost position multiple times, the pusher 30 is operated at its full stroke length to the forwardmost position (a position closer to the tip of the slope section 20 than the bottom ash extrusion port 15), thereby compressing and conveying the moist bottom ash to the slope section 20. By repeating the above operation, the relatively small particles or heavy particles contained in the hydrated bottom ash move to the lower layer, and the relatively large and light particles contained in the hydrated bottom ash are pushed to the upper layer, forming ash with a high concentration of valuable metals and ash with a low concentration of valuable metals.

[0032] In this way, the pushing surface 33 of the pusher 30 can move up to the base end of the inclined portion 20. The pushing position of the pushing surface 33 can be freely controlled using a conventional control mechanism. For example, the arm 31 is configured so that its operating position is controlled by the action of forward and backward limits, a neutral limit, and / or a proportional control solenoid valve. Because the proportional control solenoid valve can control the speed of the hydraulic cylinder in the arm, it is possible to adopt a configuration in which the neutral limit is not set. However, by having a proportional control solenoid valve and a neutral limit, more appropriate stroke adjustment can be made depending on the amount of bottom ash, and ash with a high concentration of valuable metals can be obtained.

[0033] The main configuration of the ash extrusion device of the present invention is as described above, but the characteristic parts of each embodiment shown in Figures 2 to 8 will be further described. In the description of each embodiment, the description of the above-mentioned common configuration will be omitted.

[0034] [First embodiment] In the first embodiment shown in FIG. 2, the partition 25 forming the second inclined surface is provided only near the tip of the first inclined surface 21, which is close to the inlet to the chute 40. Here, the partition 25 is arranged so that the second inclined surface is provided above the first inclined surface 21 across the entire width of the first inclined surface 21. While the wet bottom ash from the bottom surface of the water storage section 10 is compressed by the extrusion surface 33 of the pusher 30 and pushed upward along the first inclined surface 21 and transported, the water falls downward along the first inclined surface 21 and is dehydrated, and small particles or heavy components settle to the lower layer of the bottom ash, further concentrating valuable metals in the lower layer of the bottom ash, forming a highly concentrated valuable metal ash in the lower layer of the bottom ash and a low concentrated valuable metal ash in the upper layer of the bottom ash. Since particle size separation and concentration separation due to flow phenomena continue even while the moist bottom ash is being transported along the first inclined surface 21, it is desirable to select the overall length, base end position, and inclination angle of the partition 25 according to the properties of the moist bottom ash, etc. In the first embodiment, as shown in Figure 2(c), the first moist bottom ash (ash with a high concentration of valuable metals) transport path 23 is formed in the lower part of the inclined section 20, and the second moist bottom ash (ash with a low concentration of valuable metals) transport path 27 is defined by the partition 25 in the upper part of the inclined section 20.

[0035] A first guide 22 is provided at the tip of the first inclined surface 21, bending downward and inclining up to the connecting portion with the first chute 43. A partition 25 forming the second inclined surface extends beyond the tip of the first inclined surface 21, and a second guide 24 is provided at the tip of the partition 25, bending downward above the first chute 43 in the same manner as the first guide 22 and inclining downward toward the second chute 45. In this way, by providing a first guide 22 to the first chute 43 at the tip of the first inclined surface 21 and a second guide 24 to the second chute 45 at the tip of the second inclined surface, the ash with a high concentration of valuable metals can be separated and transported from the first hydrous main ash (ash with a high concentration of valuable metals) transport path 23 defined between the first inclined surface 21 and the partition 25 forming the second inclined surface to the first chute 43, and the ash with a low concentration of valuable metals can be separated and transported from the second hydrous main ash (ash with a low concentration of valuable metals) transport path 27 defined above the partition 25 forming the second inclined surface to the second chute 45.

[0036] Second Embodiment In the second embodiment shown in FIG. 3, a partition 25 forming the second inclined surface is provided extending from near the tip of the first inclined surface 21, past the first chute 43, to the inlet of the second chute 45. Here, the partition forming the second inclined surface 25 is provided above the first inclined surface 21 across the entire width of the first inclined surface 21. In the second embodiment, as shown in FIG. 3(c), the first water-containing bottom ash (ash with a high concentration of valuable metals) conveying path 23 is formed in the lower part of the inclined portion 20, and the second water-containing bottom ash (ash with a low concentration of valuable metals) conveying path 27 is formed in the upper part of the inclined portion 20. The chute 40 is positioned above the height position of the tip of the first inclined surface 21 and has a baffle plate 47 that is erected upright to a position above the inlets of the first chute 43 and the second chute 45. In the embodiment shown in FIG. 3, the baffle plate 47 does not extend to the partition 25, and there is a gap between the baffle plate 47 and the partition 25.

[0037] As in the first embodiment, the highly concentrated valuable metal ash formed in the lower layer of the bottom ash that has been dehydrated and concentrated while being pushed up along the first inclined surface 21 is guided along the first hydrous bottom ash (highly concentrated valuable metal ash) conveying path 23 defined by the partition 25 that forms the first inclined surface 21 and the second inclined surface, and is thrown into the first chute 43, while the low concentrated valuable metal ash formed in the upper layer of the bottom ash is guided along the second hydrous bottom ash (low concentrated valuable metal ash) conveying path 27 defined on the partition 25 that forms the second inclined surface, and is thrown into the second chute 45. The baffle plate 47 is erected above the chute inlet, preventing the highly concentrated valuable metal ash from being thrown into the second chute 45, enabling more reliable separation. In addition, the opening between the partition 25 and the baffle plate 47 allows the highly concentrated valuable metal ash from the first water-containing bottom ash (highly concentrated valuable metal ash) conveying path 23 to forcibly drop the water-containing bottom ash when the highly concentrated valuable metal ash does not drop into the chute due to an unpredictable event such as a bridge where a long object or a lump of water-containing bottom ash clogs the chute entrance. It is also a safety opening to allow

[0038] Third Embodiment The third embodiment shown in Figure 4 has the same configuration as the second embodiment shown in Figure 3, except that the base end of the partition 25 forming the second inclined surface is located at the same position as the base end of the first inclined surface 21.

[0039] [Fourth embodiment] The fourth embodiment shown in FIG. 5 has essentially the same configuration as the second embodiment shown in FIG. 3, but differs in the following respects. The partition 25 has a concave cross-section as shown in FIG. 5(c). The partition 25 is positioned above the first inclined surface 21 in the widthwise center thereof. The first hydrous bottom ash (ash with a high concentration of valuable metals) conveying path 23 is provided in the widthwise center of the first inclined surface 21, and an opening to the first chute 43 is provided in the widthwise center of the first inclined surface 21 as shown in FIG. 5(a). The second hydrous bottom ash (ash with a low concentration of valuable metals) conveying path 27 is provided with a concave cross-section on the second inclined surface formed by the partition 25 and on both widthwise edges of the first inclined surface 21. The second hydrous bottom ash (ash with a low concentration of valuable metals) conveying path 27 extends beyond the first chute 43 to the inlet of the second chute 45.

[0040] While the moist bottom ash is compressed and pushed up the inclined section 20, the small particle size heavy components settle, but the degree of this settling is greater in the center than at both edges of the moist bottom ash, so that ash highly concentrated in valuable metals can be formed more efficiently.

[0041] Fifth Embodiment The fifth embodiment shown in Figure 6 has the same configuration as the fourth embodiment shown in Figure 5, except that the base end of the partition 25 forming the second inclined surface is located at the same position as the base end of the first inclined surface 21.

[0042] Sixth Embodiment The sixth embodiment shown in FIG. 7 has essentially the same configuration as the fourth embodiment shown in FIG. 5, but differs in the following respects. The partition 25 is located above the first inclined surface 21, as shown in FIG. 7(b), so that the widthwise center is positioned above both widthwise edges, and the widthwise center and both widthwise edges are parallel to the first inclined surface 21. The first hydrous bottom ash (ash with a high concentration of valuable metals) conveying path 23 is defined by the partition 25 and the first inclined surface 21, as shown in FIG. 7(c), and has a convex cross-section with the widthwise center protruding upward. The opening to the first chute 43 is provided across the entire width of the inclined surface 21, as shown in FIG. 7(a). The second hydrous bottom ash (ash with a low concentration of valuable metals) conveying path 27 is defined above the partition 25, and has a concave cross-section with both widthwise edges protruding downward.

[0043] While the moist bottom ash is compressed and pushed up the inclined section 20, the small particle size heavy components settle, and the degree of this settling is greater in the center of the moist bottom ash than at both edges. However, since the small particle size heavy components also settle at both edges, a large amount of highly concentrated ash containing valuable metals can be formed more efficiently.

[0044] Seventh Embodiment The seventh embodiment shown in Figure 8 has the same configuration as the sixth embodiment shown in Figure 7, except that the base end of the partition 25 that forms the second inclined surface is located at the same position as the base end of the first inclined surface 21.

[0045] In the fourth to seventh embodiments, the partition 25 has a concave cross section with the center portion protruding downward, but it may have a convex cross section with the center portion protruding upward. The structure of the water main ash conveying passage 27 may be reversed.

[0046] [Pusher extrusion surface] In the first to seventh embodiments, a pusher having a flat extrusion surface as shown in Fig. 9 is used, but pushers having extrusion surfaces with inclined portions of various shapes as shown in Figs. 10 to 13 can be used in any combination in the first to seventh embodiments. Hereinafter, embodiments of the pusher extrusion surface will be described.

[0047] [Second embodiment of pusher] The pusher 30 shown in Figure 10 has an extrusion surface 33 located at the tip of the pusher, which is provided with an inclined portion 33c that slopes from the peripheral portion 33a toward the central portion 33b so that the central portion protrudes, and the tip of the pusher 33 is formed in a conical or pyramidal shape.

[0048] [Third Pusher Embodiment] The pusher 30 shown in Figure 11 has an inclined portion 33c on the extrusion surface 33 that slopes from the peripheral portion 33a toward the central portion 33b, the central portion 33b is flat, and the tip of the pusher 33 is formed in a conical or pyramidal base shape.

[0049] [Fourth embodiment of the pusher] The pusher 30 shown in FIG. 12 has an inclined portion 33c on the extrusion surface 33 so that the cross section is arc-shaped from the peripheral edge portion 33a, and the tip of the pusher 33 is formed in a dome shape.

[0050] [Pusher Fifth Embodiment] In the pusher 30 shown in FIG. 13, an inclined portion 33c is provided on the extrusion surface 33, inclining from a part of the peripheral edge portion 33a toward the central portion 33b, and the remaining portion of the extrusion surface 33 is formed flat.

[0051] [Other components] In addition to the above-mentioned components, the ash pusher 1 of the present invention may be equipped with any components of a known ash pusher within the scope of the present invention.

[0052] [Ash extrusion method] An ash extrusion method using the ash extrusion device 1 of the present invention will be described. Bottom ash incinerated in a stoker-type incinerator is dropped into the water storage section 10 of the ash extrusion device 1 through the bottom ash injection pipe 5. A predetermined amount of water has been added to the water storage section 10 in advance, and when the bottom ash is added thereto, it is stirred and mixed by a pusher, which will be described later, to form a wet bottom ash (slurry).

[0053] The pusher 30 is moved back and forth against the bottom ash dropped into the water reservoir 10, stirring and mixing the bottom ash and water to form a wet bottom ash (slurry). Conventionally, a hydraulic cylinder is reciprocated through its full stroke. In this invention, however, the pusher 30, located at the base end (retraction limit) of the water reservoir 10, is advanced to the center of the water reservoir 10, stopped, and then retracted to the base end, performing several reciprocating movements of approximately half a stroke to fluidize and mix the bottom ash and water without compressing or transporting them to downstream equipment. As the slurry formation progresses, relatively small particles or heavy components settle, while relatively large, light components are pushed to the upper layer, forming a highly concentrated valuable metal ash containing a high concentration of valuable metals at the bottom of the wet bottom ash. The large, light components rise to the surface, forming a low-concentrated valuable metal ash at the top of the wet bottom ash.

[0054] The amount of bottom ash fed from the stoker-type incinerator is determined by the amount of the post-combustion zone stoker that is operational after a long-term shutdown. When bottom ash is dropped, the amount is large, but conversely, when the pusher is turned on after a short stop and then drops the bottom ash, the amount is small. In other words, when a large amount of bottom ash is dropped into the water storage section 10, the stroke reciprocation is controlled to be short distance and the number of operations is large, and conversely, when a small amount of bottom ash is dropped, the stroke reciprocation is controlled to be long distance and the number of operations is small. In either case, the pusher reciprocation distance is not the full stroke length, but is less than half the stroke length. Note that the amount of dropped bottom ash can be detected by controlling the post-combustion zone stoker, and since the amount of dropped bottom ash can also be determined by, for example, a water level gauge that monitors the water level, the pusher operation can also be controlled by the water level gauge.

[0055] After stirring the main ash and water by multiple reciprocating strokes, the extrusion surface 33 of the pusher 30 is positioned at its backward limit and stopped for several tens of seconds to several minutes, ensuring time for separation based on differences in particle size and specific gravity, and allowing sedimentation and separation to occur, thereby thoroughly separating the ash with a high concentration of valuable metals from the ash with a low concentration of valuable metals.

[0056] The pusher 30 is then moved to a state where the arm 31 is fully extended (forward limit), and the hydrous bottom ash, which has formed into highly concentrated valuable metal ash and low concentrated valuable metal ash, is compressed and conveyed along the inclined section 20 to the chute 40. During transfer from the inclined section 20 to the chute 40, the highly concentrated valuable metal ash passes through the first hydrous bottom ash (highly concentrated valuable metal ash) conveying path 23, and the low concentrated valuable metal ash passes through the second hydrous bottom ash (low concentrated valuable metal ash) conveying path 27, where further settling and concentration of the valuable metals and compressed dehydration proceed. The distribution of valuable metal concentrations in the highly concentrated valuable metal ash and the low concentrated valuable metal ash varies depending on the amount of valuable metal in the bottom ash and the type of valuable metal. For example, in the case of copper, the copper concentration in the highly concentrated valuable metal ash is more than twice that of the low concentrated valuable metal ash.

[0057] The hydrous bottom ash is separated into high-concentration valuable metal ash and low-concentration valuable metal ash and then transported to chute 40, where the high-concentration valuable metal ash is fed into the first chute 43 and the low-concentration valuable metal ash is fed into the second chute 45 for known post-processing.

[0058] All of the above processes can be configured as a fully controlled automated system. These can be implemented by monitoring and controlling the stoker control, ash extrusion device control, ash extrusion device water injection control, and downstream conveyance device control using a distributed control system (DCS) installed in a separate central control room (not shown).

[0059] Furthermore, by adding a chelating agent (e.g., diethyldithiocarbamate-based chelating agent, piperazine-based chelating agent, inorganic chelating agent, etc.) or an iron co-precipitating agent such as ferric chloride to the water storage section 10 along with the water, the alkaline precipitation effect of metal ions and the iron co-precipitation effect can be used to increase the separation speed for particles with different particle sizes and specific gravity, thereby shortening the separation wait time. This makes it easier to adjust the agitation stroke length and the separation wait time for particles with different particle sizes and specific gravity depending on each facility and each type of waste, and also reduces the time required for trial operation and adjustment. The type of chelating agent and the amount used can be selected arbitrarily depending on the amount of valuable metals contained in the bottom ash, etc.

[0060] Furthermore, bubbling in the water in the water reservoir 10 can also speed up the separation of particles with different particle sizes and specific gravities.

[0061] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0062] According to the ash extrusion device and ash extrusion method of the present invention, it is possible to efficiently recover ash in which valuable metals are concentrated in the bottom ash by a wet method. In particular, the device of the present invention does not require a wastewater treatment device or a drying device, and therefore does not require the energy required for water treatment. The ash extrusion method can efficiently recover valuable metals without incurring initial or running costs, and can utilize the equipment and machinery already installed in waste incineration facilities. Therefore, it can provide a pre-treatment process for resource recovery systems that is beneficial not only to some companies and local governments, but to the entire country of Japan. [Industrial Applicability]

[0063] The device of the present invention utilizes segregation phenomena (differences in particle size and specific gravity) to concentrate trace amounts of valuable metals contained in bottom ash from existing stoker-type incineration facilities, separate it into high-concentration ash and low-concentration ash, and provide it to secondary intermediate treatment facilities or recycling facilities according to their intended use. This allows the volume reduction and resource recovery of bottom ash to function effectively as a system flow. This allows the valuable metals contained in trace amounts in bottom ash to be efficiently recovered and recycled. Meanwhile, the low-concentration ash can be reduced in volume (extended in life) by being disposed of as residue in a landfill, and can also be used in other products such as eco-cement, contributing to further resource recovery and volume reduction. This contributes to the creation of a waste-recycling society aiming for carbon neutrality by 2050.

Claims

1. a water storage section that receives and cools the bottom ash discharged from the stoker-type incinerator; a chute provided at one end of the water storage section for discharging the cooled moist bottom ash; an inclined portion inclined upward from the water storage portion to the chute; a pusher that pushes the bottom ash introduced into the water storage section toward the inclined section; An ash extrusion device for a stoker-type incinerator, comprising: The inclined portion is a first inclined surface provided so as to incline upward from the bottom surface of the water storage portion; a partition that forms a second inclined surface at a position above the first inclined surface, at least on a tip side of the first inclined surface; the second inclined surface extends beyond the tip of the first inclined surface; The partition defines a first water-containing bottom ash transport path on the first inclined surface and a second water-containing bottom ash transport path on the second inclined surface, The shot in question was a first chute that receives the first moist bottom ash dropping from the first moist bottom ash conveying path; a second chute that receives the second water-containing bottom ash dropping from the second water-containing bottom ash conveying path; An ash extrusion device for a stoker-type incinerator.

2. The ash extrusion device according to claim 1, characterized in that a baffle plate is provided between the first chute and the second chute, the baffle plate being erected above the height position of the tip of the first inclined surface.

3. 3. The ash pusher according to claim 1, wherein the pusher has a pushing surface at the tip end thereof, the pushing surface having an inclined portion formed at least in part so as to protrude in the forward direction of the pusher.

4. 3. The ash extrusion device for a stoker-type incinerator according to claim 1, wherein the pusher is capable of reciprocating a plurality of times from the backward limit position of its extrusion surface at a stroke length of half a stroke or less to flow and agitate the bottom ash and water charged into the water storage section, thereby producing moist bottom ash; the extrusion surface can be stopped for a predetermined time, and the extrusion surface can be operated at its full stroke length from the backward limit position to the forward limit position to compress and transport the moist bottom ash to the inclined section, thereby causing relatively small particles or relatively heavy components in the moist bottom ash to settle and relatively large, lightweight components to float, thereby forming a first moist bottom ash and a second moist bottom ash having different contents of valuable metals.

5. An ash extrusion method for separating and recovering bottom ash in a stoker-type incineration facility equipped with the ash extrusion device according to claim 1, a stirring and mixing process in which the bottom ash fed from the stoker-type incinerator to the water storage section is stirred and mixed by a pusher with multiple reciprocating motions of less than half the stroke length to form moist bottom ash; and a resting process in which the pusher is stopped for a predetermined time to allow relatively small particles or heavy components in the moist bottom ash to settle and relatively large light components to float. a compressing and conveying step of compressing and conveying the water-containing bottom ash to an inclined portion by advancing the pusher through its entire stroke length, The stirring and mixing step, the stationary step, and the compressing and conveying step are repeated a plurality of times to compress and convey the wet bottom ash upward along the inclined portion to a chute, thereby forming a first wet bottom ash and a second wet bottom ash having different concentrations of valuable metals; The first wet bottom ash is dropped into a first chute, and the second wet bottom ash is dropped into a second chute. Then, the water-containing bottom ash with different concentrations of valuable metals is separated and collected. The ash extrusion method is characterized by the above.

6. The ash extrusion method according to claim 5, wherein the first hydrated bottom ash is a valuable metal-rich bottom ash having a relatively high concentration of valuable metals, and the second hydrated bottom ash is a valuable metal-rich bottom ash having a relatively low concentration of organic metals.

Images