Material processing equipment and method of using material processing equipment
Patent Information
- Application Number
- JP2026513655
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-08-30
- Filing Date
- 2024-08-30
- Publication Date
- 2026-09-03
Smart Images
Figure 2026530081000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for separating non-ferrous metals from bottom ash (so-called slag) from waste incineration plants that functions as a subsystem of an integrated slag treatment process. Background Art
[0002] Worldwide, there is increasing attention to the adverse environmental impacts caused by waste disposal. Proper waste disposal requires vast areas of land, which is limited in certain urban areas or islands. Furthermore, since chemical substances and heavy metals contained in waste can contaminate groundwater, waste may exert adverse impacts on the environment including effects on groundwater. However, in addition to landfilling, waste can also cause adverse environmental impacts through incomplete separation and treatment for reuse as potential secondary materials in various industrial applications.
[0003] Separation of non-ferrous metals by eddy current separators is known from the prior art. This method is also used for the treatment of slag generated from waste incineration plants. After the slag is removed from the incinerator, the slag is substantially composed of mineral slag particles and various metals. After being removed and before being fed to the slag treatment facility, the slag is typically stored to reduce its moisture content. To date, there is no globally standardized method capable of processing mineral slag fractions and metals with sufficient quality such that both products can meet the legal requirements of various countries regarding the reuse of these two materials.
[0004] In a typical slag processing method, large particles exceeding 300 mm in size and large iron scrap particles are usually separated in the first step. The slag is then separated into different fractions using a separation device, such as one that uses a sieve. After these processes, in the third step, the resulting fractions are further separated into iron fractions and slag particles with magnetic properties. It is important to note that these process steps can be performed in different configurations depending on the system. However, regardless of the order, they must be performed before the process steps for separating non-ferrous metals from the mineral slag fractions are carried out. The separation of non-ferrous metals is usually performed using eddy current separators and is a crucial element for the economic benefit of the slag processing facility operator, significantly impacting the profitability of the facility. In waste incineration slag separation technology, the goal is to recover as many non-ferrous metals as possible in high purity. Typically, 70-90% of all non-ferrous metals can be separated using one eddy current separator per fraction or two connected in series. A significant drawback of known processes is that, when it is desired to guarantee the quality of specific non-ferrous metals, only a certain percentage of the non-ferrous metals present in the slag can be separated in an economically viable manner. To further enhance the separation, additional eddy current separators or similar methods are required. However, since the cost-effectiveness of additional eddy current separators is not guaranteed because each additional eddy current separator reduces the absolute amount of non-ferrous metals separated, other eddy current separators have not been used to date.
[0005] However, the presence of unseparated non-ferrous metals limits the reuse of mineral slag fractions in various industrial applications, such as base layer formation for road construction, cement production, or ceramics manufacturing. The heavy metals and aluminum contained in the remaining mineral slag fractions still pose an obstacle to their full global integration as by-materials. The release of heavy metals or oxidation of aluminum particles can lead to environmental pollution or a decline in material quality.
[0006] The continued decrease in landfill volume of non-recyclable materials and the growing efforts to reuse secondary resources in the fight against climate change are increasing the importance of utilizing mineral slag after separating iron and non-ferrous metal fractions.
[0007] Depending on the country and specific landfill disposal methods, reusing mineral slag fractions can save on high landfill costs, making the removal of mineral slag fractions from landfills economically beneficial for operators. Therefore, further strengthening and improving the separation of non-ferrous metals can also generate additional economic benefits for operators. [Overview of the project] [Problems that the invention aims to solve]
[0008] Therefore, the fundamental objective of the present invention is to propose a material processing facility and method that enables further improvement in the efficiency of separating non-ferrous metals contained in the bottom ash of waste incineration facilities within various slag fractions. The objective is to separate the non-ferrous metals from the remaining mineral slag fraction and enable both to be reused as sustainable secondary raw materials.
[0009] The present invention relates to a subsystem of a slag treatment facility equipped with an eddy current separator having an inlet for slag fractionation, an outlet for mineral slag fractionation, and an outlet for non-ferrous metal fractionation, and to a method for treating slag from a waste incineration facility equipped with an eddy current separator integrated into a closed-loop process that separates the slag into a mineral slag fraction and a non-ferrous metal fraction in several cycles.
[0010] Such apparatus and methods are designed to ensure particularly high separation efficiency of non-ferrous metal fractions from high-purity mineral slag fractions.
[0011] Therefore, an object of the present invention is to propose a material processing apparatus and method for providing particularly high-purity material products (mineral slag fraction and non-ferrous metals) from slag from which iron particles have already been removed. This is achieved using a closed-loop process, which improves separation efficiency without the need to integrate additional eddy current separators. [Means for solving the problem]
[0012] The object of the present invention is solved by a material processing apparatus having the configuration of claim 1.
[0013] Further advantageous embodiments are the subject of the dependent claims.
[0014] The method according to the present invention can be carried out continuously if properly adjusted. Preferably, it is carried out as a batch process, and the batch is preferably supplied to the eddy current separator at least twice. The material processing facility has two storage containers. The first storage container serves to store the incoming slag and is located upstream of the eddy current separator. The second storage container is located on the return line of the mineral slag fraction. The material to be separated is first supplied to the eddy current separator as untreated slag, and a second time it is supplied to the eddy current separator as a mineral slag fraction of the material that was not separated by the eddy current separator. This loop can be repeated indefinitely until the material is removed from the loop.
[0015] To guarantee a perfect batch principle, two storage containers are necessary. Without storage space, it is necessary to calculate how much material can effectively fit within the loop. If untreated slag is supplied to the loop, at some point the mineral slag fraction may have already been processed once in the eddy current separator and be returned to the eddy current separator. If untreated slag is still being pumped into the loop from the first storage container, the processing rate will increase until the closed-loop system eventually reaches its maximum separation capacity and the eddy current separator is overloaded. Therefore, installing two storage containers of the same size ensures sufficient space to accommodate the material within the loop. The eddy current separator is usually the lowest throughput component in the loop and acts as a bottleneck.
[0016] The return line typically consists of various transport systems that carry the mineral slag fraction to a second storage container. Commonly used are combinations of vibrating conveyor systems, conveyor belts, or bucket elevators.
[0017] The mineral slag fractionation loop includes a material removal outlet. Material can be transported from the system through this material removal outlet during each cycle. It is advantageous for the material removal outlet to be located on the return line of the mineral slag fractionation. This allows batches of material to be removed from the system after separation by the eddy current separator. The material removal outlet can be, for example, a reversing chute, a switching valve, or a hinged box with two outlets.
[0018] To improve the separation efficiency of non-ferrous metals, one or more additional eddy current separators can be installed between the outlet and return line for mineral slag fractionation. The non-ferrous metals separated from each eddy current separator are then combined.
[0019] The eddy current separator and at least one further eddy current separator preferably include an eddy current separator. There are various types of eddy current separators. The basic variations mainly relate to the eccentric or concentric magnetic drum, the number of magnets inside the magnetic drum, the working width, and whether the separation peak when separating non-ferrous metals from mineral slag fractions can be adjusted. The settings of the eddy current separator also affect the separation efficiency of non-ferrous metals. The amount of slag to be processed, the speed of the conveyor belt inside the eddy current separator, the separation peak position, and the rotation speed of the rotating magnetic drum can be adjusted. In eddy current separators with eccentric magnetic drums, the position of the magnets inside the drum can also be changed.
[0020] Eddy current separation is based on the repulsive properties caused by the electrical conductivity of individual particles induced by a variable magnetic field in an eddy current separator. The electrical conductivity of the particles is the primary factor determining the magnitude of the particle repulsion force. However, the success of separating non-ferrous metals in the slag industry depends on the complex interaction between electrical conductivity, material density, particle size, and the shape of individual particles.
[0021] For example, aluminum particles have a low density and high electrical conductivity, resulting in strong repulsion and clearly defined orbitals, making them easy to separate. In contrast, lead has a high density and low electrical conductivity, resulting in weaker orbitals and making separation difficult.
[0022] Other factors also play a role. Flat particles may experience significant air resistance in their orbits, weakening their trajectories and making separation more difficult. Smaller particles may also experience weaker repulsive forces due to their size, potentially weakening their trajectories and making separation more challenging. The orientation of particles in space also affects separation when they enter a magnetic field.
[0023] Therefore, the settings for an eddy current separator are determined based on empirical data, not on mathematical formulas. The selection of the particle size range to be derived together through the same eddy current separator also determines the separation efficiency.
[0024] The purpose of an eddy current separator is typically to separate all non-ferrous metals from the mineral slag fraction. This involves a compromise: separating more non-ferrous metals increases the presence of mineral slag particles in the non-ferrous metal fraction. Conversely, separating less non-ferrous metals means fewer mineral particles in the non-ferrous metal fraction, but more non-ferrous metals remain in the mineral slag fraction. It should be noted that because the properties of the separated non-ferrous metals are highly heterogeneous, a single eddy current separator is not sufficient to separate all non-ferrous metal particles with high purity. Therefore, to achieve high separation efficiency of non-ferrous metals, it is advantageous to process the slag using multiple eddy current separators in series. This is because non-ferrous metal particles that are not separated due to unfavorable arrangements in the first separator may be in more favorable arrangements in subsequent separators and thus can be separated well. Thus, increasing the number of separators increases the probability that non-ferrous metals are positioned favorably for separation in one of the separators.
[0025] The number of loops completed before the material is discharged through the material removal outlet can be determined by two principles: either by a predefined number of loops, or by a fill level sensor in the first storage container. According to the second principle, batches of material can be processed in the loop until the sensor signals that the first storage container, containing new slag, has reached its maximum capacity. The sensor then signals that the batch in the loop needs to be moved out of the system so that a new batch of unprocessed slag can be transported into the loop. This optimizes the utilization of the material processing equipment. The fluctuating material inflow of unprocessed slag being transported to the first storage container allows for maximum utilization of the closed-loop process. Therefore, different batches can be processed using various loop counts.
[0026] It is advantageous that the feed silo and the vibrating conveyor are integrated into the closed-loop process upstream of the first eddy current separator. The feed silo and the subsequent vibrating conveyor enable weighing of the material and uniform conveyance of the material to the eddy current separator. To ensure uniform conveyance, only one vibrating conveyor is incorporated upstream of each eddy current separator connected in series.
[0027] To further optimize the separation of non-ferrous metals, it is advantageous to change the position of the separation peak of the eddy current separator that separates non-ferrous metals from mineral slag fractions according to cycles. This is because the non-ferrous metal content in the mineral slag fraction decreases after each cycle, so the process of separating non-ferrous metals from the mineral slag fraction exhibits different behavior.
[0028] To maintain high quality of the two main fractions, it is advantageous to provide a system such as a switching valve downstream of the outlet of the eddy current separator for non-ferrous metals, which can convey separated non-ferrous metals to two different lines. The switching valve allows setting the position of the separation peak for the final cycle to separate as much residual non-ferrous metal as possible from the mineral slag aggregate. When complete separation of non-ferrous metals is achieved in the final cycle, a large amount of mineral slag particles in the separated non-ferrous metal fraction must be accepted as impurities in this cycle. To ensure that this separated amount does not degrade the quality of the previously separated non-ferrous metals, the switching valve can be actuated to generate a third fraction. This third fraction contains the non-ferrous metals separated from the final cycle, which have been processed using the eddy current separator. This third fraction can be further separated in addition to the non-ferrous metal fraction and the mineral slag fraction. When a plurality of eddy current separators are connected in series, only the last eddy current separator connected in series has a switching valve for the separated non-ferrous metal fraction. The switching valve is incorporated into the system before the non-ferrous metals separated from the eddy current separators merge.
[0029] It is also advantageous that if the previous processing system did not separate iron particles and magnetic particles, this separation process is performed in a closed loop system as described. The separation of iron and magnetic materials must be performed upstream of the eddy current separator. Iron and magnetic materials adversely affect the non-ferrous metal separation process and may damage the magnetic drum of the eddy current separator. If separation of iron material from this material fraction has not yet been performed, it is advantageous to install a magnetic separator in the line between the outlet of the first storage container and upstream of the inlet of the feed silo. In this process, iron particles and magnetic particles are separated upstream of the eddy current separator.
[0030] The line between the two storage containers and the feed silo or magnetic separator generally consists of a discharge unit arranged immediately downstream of the storage container, and a combination of a vibrating conveying system, a conveyor belt, or a pipeline that transports slag to the feed silo or magnetic separator.
[0031] Considering the entire system, substantially two products need to be treated. One is a mineral slag fraction primarily present in the loop, and the other is non-ferrous metals such as aluminum, copper, silver, gold, lead, zinc, tin, and palladium separated from the mineral slag fraction by the eddy current separator. The mineral slag fraction is the main fraction in terms of its quantity.
[0032] Advantageous embodiments are shown in the drawings and will be described in more detail below. Identical elements may be provided with the same reference numerals. The drawings show the following. Brief Description of the Drawings
[0033] [Figure 1] Shows a flow chart of a simple apparatus provided with a switching valve for the non-ferrous metal fraction separated from the final loop. [Figure 2] Shows an expanded flow chart of a second eddy current separator. [Figure 3] Shows a flow chart similar to Fig. 2, expanded with an additional eddy current separator. [Figure 4]An extended flowchart based on the flowchart for material processing equipment shown in Figure 1 is presented. [Figure 5] A flowchart similar to Figure 1, extended with a magnetic separator, is shown. [Modes for carrying out the invention]
[0034] In the material processing facility 1, shown as a flowchart in Figure 1, slag 2 is transported into the first storage container 3. As soon as the first storage container 3, containing the slag 2, reaches its maximum capacity, the first cycle begins. Unprocessed slag 4 is transported from the first storage container 3 to the supply silo 7 via line 6 through the outlet 5 of the first storage container 3. The unprocessed slag 4 is transported from the supply silo 7 to the inlet 27 of the eddy current separator 9 by a vibrating conveyor 8. In the eddy current separator 9, the unprocessed slag 4 is separated for the first time. The eddy current separator 9 has an outlet 10 for the mineral slag fraction 11 and an outlet 12 for the non-ferrous metal fraction 13. The mineral slag fraction 11 is transported into the second storage container 15 by a primary return line 14. During the separation of untreated slag 4 by the eddy current separator 9, the mineral slag fraction 11 is not transported by line 16 from the second storage container 15 toward the supply silo 7. Once the entire material batch of untreated slag 4 has been transported from the first storage container 3, the transport of additional untreated slag 4 toward the supply silo 7 is stopped. Once the entire batch of untreated slag 4 from the first storage container 3 has been separated using the eddy current separator 9, a new cycle begins. The mineral slag fraction 11 is transported by outlet 29 and line 16 from the second storage container 15 toward the supply silo 7. A certain number of cycles can be performed via the eddy current separator 9 depending on the amount of slag 2 flowing into the first storage container 3. As soon as the first storage container 3, containing new slag 2, reaches its maximum capacity, the mineral slag fraction 11 in the loop is removed from the system by material removal outlet 17. Once the entire treated mineral slag fraction 11 is removed from the loop via the material removal outlet 17, new untreated slag 4 is transported from the first storage container 3 towards the supply silo 7. Here, the new batch begins with the new untreated slag 4 and is separated using the eddy current separator 9. The transport from the two storage containers 3, 15, as well as the discharge of the mineral slag fraction 11 from the system, are coordinated during operation. This flowchart also shows a switching valve 18 downstream of the outlet 12 for the non-ferrous metal fraction 13 of the eddy current separator 9.Before the final cycle of the batch begins, the switching valve 18 for the separated non-ferrous metal fraction 13 of the eddy current separator 9 can be switched to allow this separated non-ferrous metal fraction 19 to be discharged separately from the final cycle.
[0035] The material processing equipment, shown as a flowchart in Figure 2, shows an expansion downstream of the outlet 10 with an additional vibrating conveyor 31 and an additional eddy current separator 20, which further separates the mineral slag fraction 11 from the additional non-ferrous metals 13 before the mineral slag fraction 11 is transported into the second storage container 15 by the primary return line 14. The non-ferrous metal fraction 13 separated from the two eddy current separators 9 and 20 is combined after separation. The flowchart also shows a switching valve 18 downstream of the outlet 12 for the non-ferrous metal fraction 13 of the eddy current separator 20. Before the final cycle of the batch begins, the switching valve 18 for the separated non-ferrous metals 13 of the eddy current separator 20 can be switched to discharge this separated non-ferrous metal fraction 19 separately from the final cycle.
[0036] In the flowchart shown in Figure 3, the equipment shown in Figure 2 is extended by further vibrating conveyors 32, 33 and eddy current separators 21, 22. For this purpose, downstream of the outlet 10 for the mineral slag fraction 11, the equipment has a number of further vibrating conveyors 32, 33 and further eddy current separators 21, 22 to separate the mineral slag fraction 11 from the non-ferrous metals 13 again before the mineral slag fraction 11 is then transported to the second storage container 15 by the primary return line 14. The separated non-ferrous metal fractions 13 from all the eddy current separators 9, 20, 21, 22 are combined after separation. As shown in this flowchart, the last eddy current separator 22 connected in series downstream of the outlet 12 for the non-ferrous metal fraction 13 has a switching valve 18.
[0037] If the desired number of loops for separating non-ferrous metals 13 from the untreated slag 4 or mineral slag fraction 11 is not achieved, the material processing equipment 1 can be expanded as shown in Figure 4. By expanding the equipment shown in Figure 1 into the same parallel system, the number of loops for the incoming slag 2 can be doubled. The slag 2 is divided or halved before reaching the first storage container 3. Part of the slag 2 is transported to the first storage container 3 of the left-hand system 23, and the other part is transported to the first storage container 3 of the right-hand system 24. The slag 2 is then separated as shown in Figure 1.
[0038] If iron and magnetic slag 25 have not yet been separated upstream of the material processing facility 1, the material processing facility 1 can be expanded with a magnetic separator 26. In the flowchart shown in Figure 5, the facility shown in Figure 1 is expanded with a magnetic separator 26. The magnetic separator 26 is incorporated into the line 6 between the outlet 5 of the first storage container 3 and the supply silo 7. This generates unprocessed slag 4 to be transported toward the supply silo 7 and iron and magnetic slag fractions 25 to be discharged from the system.
[0039] Generally, the material processing equipment 1 has two strategies for increasing the separation efficiency of non-ferrous metals. The material processing equipment is expanded by connecting one or more additional eddy current separators 20, 21, 22 in series, as shown in Figures 2 and 3. Alternatively, as shown in Figure 4, the amount of slag 2 is halved by an additional parallel system to halve the filling rate of the first storage container 3. Thus, the residence time of the slag batch in the loop is doubled, and the number of cycles can also be doubled. These two strategies can also be combined. [Explanation of Symbols]
[0040] 1. Material Processing Equipment 2 slags 3. First storage container 4. Untreated slag 5. Outlet of the first storage container 6. Line from the first storage container to the supply silo 7. Supply silo 8. Vibration conveyor 9 Eddy current separation device 10. Outlet for mineral slag fractionation 11. Mineral slag fractionation 12. Outlet for separated non-ferrous metal fraction 13 Non-ferrous metal fraction 14. Primary return line 15. Second storage container 16. Line from the second storage container to the supply silo. 17 Material removal outlet 18. Switching valve 19. Non-ferrous metal fractionation from the final cycle. 20 Further Eddy Current Separators 21 Further Eddy Current Separators 22 Further Eddy Current Separators 23 Left side system 24 Right side system 25 Iron and magnetic slag 26 Magnetic Separator 27 Inlet of the eddy current separator 28 Entrance to the vibrating conveyor 29. Outlet of the second storage container 30 Mineral slag discharged from the system 31 Further vibrating conveyor 32 Further vibrating conveyor 33 Further vibrating conveyor
Claims
1. A material processing facility (1) for separating non-ferrous metals (13) from slag (2), An inlet (27) for untreated slag (4) or mineral slag fraction (11), An outlet (10) for mineral slag fractionation (11), An outlet (12) for the separated non-ferrous metal fraction (13) and The device includes an eddy current separator (9) having The aforementioned material processing equipment (1) is A first storage container (3) is provided upstream of the inlet (27) for untreated slag (4), An outlet (5) for untreated slag (4) from the first storage container (3), The line (6) from the outlet (5) to the inlet (27) of the eddy current separator (9) and In the material processing equipment (1) equipped with, The system includes a primary return line (14) from the outlet (10) for the mineral slag fraction (11) to a second storage container (15), The material processing equipment (1) is characterized in that the second storage container (15) has an outlet (29) and a line (16) leading from the outlet (29) to the inlet (27) of the eddy current separator (9).
2. The material processing apparatus according to claim 1, characterized in that the material removal outlet (17) for the mineral slag fraction (11) is provided in the primary return line (14) upstream of the second storage container (15).
3. The material processing equipment according to claim 1 or 2, characterized in that the vibrating conveyor (8) is provided upstream of the inlet (27) of the eddy current separator (9).
4. The material processing equipment according to claim 3, characterized in that the supply silo (7) is located upstream of the inlet (28) of the vibrating conveyor (8).
5. The material processing apparatus according to claim 3 or 4, characterized in that a further vibrating conveyor (31), followed by a further eddy current separator (20), is provided between the outlet (10) for the mineral slag fraction (11) and the material removal outlet (17).
6. The material processing apparatus according to claim 3 or 4, characterized in that a plurality of further vibrating conveyors (32, 33) and further eddy current separators (21, 22) are provided between the outlet (10) for the mineral slag fraction (11) and the material removal outlet (17).
7. The material processing equipment according to any one of claims 4 to 6, characterized in that a magnetic separator (26) is provided between the outlet (5) for the unprocessed slag (4) and the inlet of the supply silo (7).
8. The material processing apparatus according to any one of claims 1 to 7, characterized in that a switching valve (18) is provided downstream of the outlet (12) for the separated non-ferrous metal fraction (13).
9. A method of using the material processing equipment (1) according to any one of claims 1 to 8, characterized in that the material is processed in a batch process and the slag (2) is supplied to the eddy current separator (9) at least twice.
10. The method according to claim 9, characterized in that, while the untreated slag (4) is being processed, the slag (2) in which the non-ferrous metal (13) has not yet been separated is stored in the first storage container (3).
11. The method according to claim 9 or 10, characterized in that a batch of untreated slag (4) is removed from the loop after a certain number of cycles in the material processing equipment (1), and then a batch of new slag (2) is supplied from the first storage container (3) to the supply silo (7) via the outlet (5).
12. The method according to any one of claims 9 to 11, characterized in that a batch of material is transported within a loop system until the incoming slag (2) reaches a predetermined filling level in the first storage container (3).
13. The method according to any one of claims 9 to 11, characterized in that the number of cycles of each slag batch in the material processing equipment (1) can be changed according to the amount of slag (2) flowing into the first storage container (3) per unit time.
14. The method according to any one of claims 9 to 13, characterized in that the separation peak position of the eddy current separator (9) for separating the non-ferrous metal fraction (13) is changed after at least one cycle, preferably after each cycle.
15. The method according to any one of claims 9 to 14, characterized in that the slag originates from a waste incineration facility and has a moisture content of less than 5% by weight.
16. The method according to any one of claims 9 to 18, characterized in that the slag fraction to be processed has a particle size of less than 100 mm.
17. Use of a material processing facility (1) according to any one of claims 1 to 8 for processing bottom ash from a waste incineration facility.