Device and method for electrostatically separating silicon

Abstract

The invention relates to a device for electrostatically separating semiconductor particles, in particular silicon particles, from a material mixture of solar cell residue, said material mixture comprising semiconductor particles, in particular silicon particles, and non-conductive particles, in particular plastic and / or glass particles. The device has a first corona electrode (4) for electrostatically charging the material mixture, a first grounded electrode (5) for discharging the semiconductor particles contained in the material mixture, and a first static electrode (6) for generating an electric field between the first grounded electrode (5) and the first static electrode (6). The invention also relates to a corresponding method for electrostatically separating semiconductor particles. In order to allow an economical separation of silicon from solar module waste, a first infrared emitter (3) is provided for irradiating the material mixture with medium-wave infrared radiation, the first infrared emitter (3) being positioned such that the material mixture passes through the first infrared emitter (3) upstream of the first corona electrode (4) during operation.

Description

[0001] Device and method for the electrostatic separation of silicon

[0002] The present invention relates to a device for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture of solar cell residues with semiconductor particles, in particular silicon particles, and non-conducting particles, in particular plastic and / or glass particles, comprising a first corona electrode for electrostatically charging the material mixture, a first grounded electrode for discharging the semiconductor particles contained in the material mixture, and a first static electrode for generating an electric field between the first grounded electrode and the first static electrode. The present invention further relates to a method for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture of solar cell residues with semiconductor particles, in particular silicon particles, and non-conducting particles, in particular plastic and / or glass particles.

[0003] Solar modules are made from various materials. The most important components of a solar module are the solar cells. These are usually made of silicon. The solar cells are sandwiched between two plastic films. A glass plate is typically used on the front side facing the sun. The back side is covered with a backsheet made of glass or plastic. Most solar modules are mounted in an aluminum frame, which provides stability and allows for secure installation.

[0004] At the end of their life cycle, solar modules are typically shredded for recycling. Large fragments of the aluminum frame and glass are recovered through screening. This screening process regularly meets the legally mandated recycling quota of 85%. After screening, a fine granulate remains, typically consisting of approximately 80% glass, 10% silicon, and 10% plastic by weight. The specific weight fractions of the granulate can vary depending on the recycling process. Separating silicon from this granulate is currently expensive and complex, so the granulate is generally not used further.

[0005] In principle, electrostatic separation is suitable for recovering silicon from a corresponding granulate. Electrically conductive materials can be separated from electrically non-conductive materials using electrostatic separation.

[0006] In electrostatic separation, the material mixture to be separated is electrostatically charged, for example by a corona electrode, and placed on a grounded electrode. The electrically conductive particles of the material mixture transfer their accumulated charge to the grounded electrode, so that the electrically conductive particles are no longer attracted to it. The particles of an electrically non-conductive material cannot transfer their charge and remain attached to the grounded electrode longer, detaching later due to a rotational movement of the grounded electrode. A static electrode generates an electric field between the grounded electrode and the static electrode. The static electrode has the opposite polarity. The static electrode exerts an attractive force on the electrically conductive particles and deflects them, thus separating them from the electrically non-conductive particles.

[0007] Silicon, as a semiconductor, is electrically conductive only within a specific temperature range when undoped. Glass and plastic are non-conductive materials. Therefore, it is theoretically possible to separate silicon from a mixture of materials including silicon, glass, and plastic using electrostatic separation.

[0008] A low moisture content in the material mixture is essential for good separation efficiency. If the moisture content is too high, even electrically non-conductive materials like glass become electrically conductive due to a thin film of water on their surface, rendering electrostatic separation ineffective or insufficient. Therefore, a maximum residual moisture content of 0.05 wt% to 0.2 wt% is considered a guideline for the successful electrostatic separation of such material mixtures. To comply with this limit, material mixtures must be dried before electrostatic separation. This process is time-consuming, energy-intensive, and therefore expensive. Consequently, electrostatic separation for separating silicon from solar module waste is not yet economically viable.

[0009] Against this background, the present invention aims to provide a method for separating a semiconductor which enables the economical separation of silicon from solar module waste.

[0010] The aforementioned problem is solved according to the invention by a device for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture containing semiconductor particles, in particular silicon particles, and non-conducting particles, in particular plastic and / or glass particles, comprising a first corona electrode for electrostatically charging the material mixture, a first grounded electrode for discharging the semiconductor particles contained in the material mixture, and a first static electrode for generating an electric field between the first grounded electrode and the first static electrode, in which a first infrared emitter is provided for irradiating the material mixture with medium-wave infrared radiation, wherein the first infrared emitter is arranged such that the material mixture passes the first infrared emitter in front of the first corona electrode during operation.

[0011] The aforementioned problem is further solved according to the invention by a method for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture comprising semiconductor particles, in particular silicon particles, and non-conducting particles, in particular plastic and / or glass particles, preferably with a device according to one of claims 1 to 8, comprising the following steps: providing a material mixture comprising particles of a first material and at least a second material, wherein the first material is a semiconductor, in particular silicon, and the second material is a non-conductor, in particular plastic and / or glass; irradiating the material mixture with medium-wave infrared radiation using an infrared emitter; charging the material mixture with a corona electrode; passing the material mixture past a grounded electrode; and generating an electric field by means of a static electrode.

[0012] The invention recognizes that medium-wave infrared radiation couples significantly better into silicon than into glass or plastic. Accordingly, the electrical conductivity of silicon can be rapidly and substantially increased by irradiation with medium-wave infrared radiation, while glass and plastic particles retain their electrically insulating properties. Irradiation with medium-wave infrared rays allows silicon particles to be heated intensely over a short heating path, for example to a temperature of 150°C, thereby increasing their electrical conductivity, whereas glass and plastic particles are not heated as much, for example, only to just under 100°C.

[0013] At an increased temperature, silicon particles have a greater capacity to hold a charge. This allows for an increased voltage during the subsequent electrostatic separation process, resulting in a stronger charge on the particles of the material mixture. Consequently, improved separation efficiency can be achieved during electrostatic separation. This enables enhanced separation of silicon particles from a material mixture comprising silicon, glass, and plastic. Furthermore, the invention recognizes that medium-wave infrared radiation has the property of coupling directly into water molecules. This results in efficient surface drying of the material mixture and thus a reduction in the conductivity of the glass and plastic. For this reason, separate drying can either be completely omitted or only minimally required.

[0014] After irradiation of the material mixture with medium-wave infrared radiation, the electrostatic separation of the material mixture, known from the prior art, can be carried out to separate the silicon particles. For this purpose, the material mixture is electrostatically charged by a first corona electrode and placed on a first grounded electrode. The electrically conductive particles of the material mixture transfer their absorbed charge to the first grounded electrode, so that the electrically conductive particles, and in particular the silicon particles, are not attracted to the first grounded electrode or are attracted only minimally. The particles made of an electrically non-conductive material, in particular glass and plastic particles, cannot transfer the charge or can only do so very slowly and adhere to the first grounded electrode. A first static electrode generates an electric field between the first grounded electrode and the first static electrode.The first static electrode exerts an attractive force on the electrically conductive particles, especially the silicon particles, and deflects them so that they are separated from the electrically non-conductive particles, especially the glass and plastic particles.

[0015] The following describes various embodiments of the device and the method, each embodiment being independent of the other. Furthermore, the individual embodiments can be combined with one another as desired.

[0016] In a preferred embodiment of the invention, the first infrared emitter is configured to irradiate the material mixture with medium-wave infrared radiation from 1,600 nm to 5,000 nm, particularly from 1,900 nm to 4,500 nm, especially preferably from 2,300 nm to 4,000 nm, and more preferably from 2,500 nm to 3,000 nm. Such infrared radiation has proven particularly advantageous for heating silicon particles and increasing their conductivity while simultaneously achieving a good drying effect.

[0017] Particularly preferably, the first infrared emitter and a first vibratory conveyor are arranged at a distance of 1 cm to 50 cm, particularly 1.5 cm to 40 cm, preferably 2 cm to 30 cm, particularly preferably 2.5 cm to 20 cm, and more preferably 3 cm to 10 cm from each other. This ensures effective irradiation with medium-wave infrared radiation.

[0018] The first vibratory feeder ensures the most uniform distribution possible of the material mixture, minimizing the number of particles stacked on top of each other. The intensity and vibration of the vibratory feeder can advantageously be adjusted, allowing it to be optimally adapted to different material mixtures and quantities. A thin and uniform application of the material mixture is beneficial for ensuring uniform irradiation of the mixture with medium-wave infrared radiation, as the effect of infrared radiation decreases with a greater layer thickness. A thin and uniform application of the material mixture is also advantageous for optimal electrostatic charging of the particles by the first corona electrode.

[0019] Advantageously, the first corona electrode and the first vibratory feeder are arranged at a distance of at least 3 cm, preferably at least 7 cm, and particularly preferably at least 10 cm. With such an arrangement, a small overall size is achieved combined with high performance of the corona electrode.

[0020] In an advantageous embodiment of the invention, the first infrared emitter has a power output of 1 kW to 6 kW per 100 kg / h of material mixture, preferably 2 kW to 5 kW per 100 kg / h of material mixture, and particularly preferably 2.5 kW to 3.5 kW per 100 kg / h of material mixture. Such power outputs have proven advantageous for effectively heating silicon particles, increasing their conductivity, and simultaneously achieving a good drying effect.

[0021] Advantageously, the first grounded electrode and / or the first static electrode are designed as roller electrodes, with a brush preferably being provided on the first grounded electrode and / or the first static electrode for removing particles of the material mixture adhering to the electrodes. The use of roller electrodes that rotate during operation has proven practical to ensure good guidance of the material mixture through the device.

[0022] In a preferred embodiment of the invention, at least one splitter, preferably several splitters, is provided for guiding the material mixture. With the aid of splitters, it is possible to guide the individual particles at appropriate points and thus achieve a higher separation efficiency.

[0023] Advantageously, a second corona electrode is provided for electrostatically charging the material mixture, a second grounded electrode for discharging the semiconductor particles contained in the material mixture, a second static electrode for generating an electric field between the second grounded electrode and the second static electrode, and a second infrared emitter. The corona electrodes, the grounded electrodes, the static electrodes, and the infrared emitters are arranged such that the separation of the semiconductor particles from the material mixture occurs in two stages. Multi-stage separation of the material mixture is advantageous to increase the separation efficiency and / or the yield of the separation process.

[0024] The first stage of electrostatic separation divides the material mixture into a conductive fraction and a non-conductive fraction. Electrostatic separation processes typically do not achieve perfect separation of silicon particles from a material mixture comprising silicon, glass, and plastic particles. One source of error can be that silicon particles are arranged on top of glass or plastic particles when placed on the grounded electrode. As a result, these silicon particles cannot transfer their charge to the grounded electrode and end up in the non-conductive fraction. Alternatively, glass or plastic particles can be located on top of silicon particles if they are in the electric field between the grounded electrode and the electrostatic electrode. This can cause these glass or plastic particles to be carried along by silicon particles into the conductive fraction.For this reason, it may be useful to provide for a further separation stage.

[0025] The conductor fraction and / or the non-conductor fraction can undergo a second stage of electrostatic separation to increase the silicon yield and the separation efficiency. Alternatively, the second stage of electrostatic separation can be performed on only one fraction.

[0026] In the second stage, the electrostatic separation process is repeated according to the same principle. Silicon particles that ended up in the non-conductive fraction in the first stage can be recharged and recovered in a second stage. This increases the silicon yield. Particles of electrically non-conductive material that ended up in the conductive fraction can also be recharged for subsequent sorting. This improves the separation efficiency. Additional stages can be added if required.

[0027] In multi-stage electrostatic separation, it is important to note that in a downstream separation step, both the heating power and the voltage can and should be set lower than in the upstream separation step, because the particles in the material mixture retain residual heat and charge from the upstream separation stage. If the voltage in the downstream separation stage is not reduced, sparking and a momentary drop in the electric field between the grounded electrode and the static electrode can occur. This must be avoided.

[0028] In a preferred embodiment of the method, the material mixture is irradiated with medium-wave infrared radiation in a range of 1,600 nm to 5,000 nm, particularly from 1,900 nm to 4,500 nm, especially preferably from 2,300 nm to 4,000 nm, and more preferably from 2,500 nm to 3,000 nm. Such infrared radiation has proven particularly advantageous for heating silicon particles, increasing their conductivity, and simultaneously achieving a good drying effect.

[0029] Advantageously, the semiconductor particles are heated by irradiation with medium-wave infrared radiation to a temperature of 30°C to 140°C, preferably 50°C to 130°C, particularly preferably 70°C to 125°C, and more preferably 90°C to 120°C. Such heating has a beneficial effect on the electrical conductivity of the semiconductor particles and also on their charge-accumulating capacity.

[0030] In a preferred embodiment of the invention, solar module waste containing silicon particles is provided as a material mixture to be separated. With a suitable material mixture, improved separation efficiency and a higher silicon yield have been achieved in practice.

[0031] The provided material mixture preferably has a moisture content of up to 3 wt.%, preferably up to 2 wt.%. Within this range, silicon particles can be separated from the provided material mixture with satisfactory separation efficiency. The material mixture is particularly preferably provided with a particle size of 40 pm to 3 mm. The inventive method can particularly well separate semiconductor particles, especially silicon particles, from non-conductor particles when using a material mixture comprising particles with a size of 40 pm to 3 mm.

[0032] In an advantageous embodiment of the process, a voltage of 10 kV to 30 kV is applied to the static electrode and / or the corona electrode. A corresponding potential difference between the grounded electrode and the static electrode has proven particularly useful in practice for electrostatically separating semiconductor particles, especially silicon particles, from non-conducting particles. A corresponding voltage at the corona electrode has also proven useful for effectively charging the particles of the material mixture.

[0033] Electrostatic separation is particularly preferably carried out in multiple stages, especially in two stages. In multi-stage electrostatic separation, the electrostatic separation is performed in several stages or repeated once or several times.

[0034] A two-stage electrostatic separation process therefore requires two corona electrodes for electrostatically charging the material mixture, two grounded electrodes for discharging the semiconductor particles contained in the material mixture, two static electrodes to generate an electric field between the grounded and static electrodes, and two infrared emitters. The corona electrodes, grounded electrodes, static electrodes, and infrared emitters are arranged such that the separation of the semiconductor particles from the material mixture occurs in two stages. A three-stage separation process requires three components of each type, and so on. Multi-stage separation of the material mixture is advantageous for increasing the separation efficiency and / or the yield of the separation process.

[0035] The first stage of electrostatic separation divides the material mixture into a conductive fraction and a non-conductive fraction. Both fractions can then undergo further electrostatic separation independently in a second stage to increase the silicon yield and the separation efficiency of the process. Alternatively, the second stage of electrostatic separation can be performed on only one fraction.

[0036] In the second stage, the electrostatic separation process is repeated according to the same principle. Silicon particles that ended up in the non-conductive fraction in the first stage can be recharged and recovered in a second stage. This increases the silicon yield. Particles of electrically non-conductive material that ended up in the conductive fraction can also be recharged for subsequent sorting. This improves the separation efficiency. Additional stages can be added if required.

[0037] Advantageously, in multi-stage electrostatic separation, the heating power generated by the infrared emitter and / or the electric field produced by the static electrode are set lower in a downstream stage than in an upstream stage. In a downstream separation stage, the particles from the material mixture retain residual heat and charge from the upstream separation step. If the voltage is not reduced in the downstream separation step, sparking and a momentary drop in the electric field between the grounded electrode and the static electrode can occur. This must be avoided. Further features and advantages of the device and the method will become apparent from the following description of exemplary embodiments, with reference to the accompanying drawing.

[0038] The drawing shows

[0039] Fig. 1 shows a schematic representation of a device according to the invention for the electrostatic separation of silicon particles from a material mixture comprising plastic, glass and silicon.

[0040] Fig. 1 shows a preferred embodiment of a device according to the invention for the electrostatic separation of silicon particles from a material mixture containing silicon, plastic, and glass particles. As shown in the legend at the top right of Fig. 1, the plastic particles are represented by a white circle, the glass particles by a white square, and the silicon particles by a black rectangle.

[0041] The material mixture containing silicon, plastic, and glass particles is conveyed from a hopper (not shown in Fig. 1) via a vibrating and bucket conveyor (also not shown in Fig. 1) and fed into the device according to the invention via a distribution hopper 1. The material mixture migrates from top to bottom within the device shown in Fig. 1.

[0042] The material mixture initially falls onto a first vibratory conveyor 2. This ensures the most uniform distribution possible of the material mixture, minimizing the number of particles stacked on top of each other. The intensity and vibration of the vibratory conveyor 2 can advantageously be adjusted so that it can be optimally adapted to different material mixtures and quantities. A first infrared emitter 3 is positioned above the first vibratory conveyor 2, irradiating the material mixture with medium-wave infrared radiation. The thin and uniform application of the material mixture by the first vibratory conveyor 2 is advantageous for ensuring uniform irradiation of the material mixture with medium-wave infrared radiation, since the effect of the infrared radiation decreases with a greater layer thickness of the material mixture.

[0043] Medium-wave infrared radiation couples much more readily into silicon particles than into glass and plastic particles. Consequently, the electrical conductivity of silicon particles can be rapidly and significantly increased by irradiation with medium-wave infrared radiation, while glass and plastic particles retain their electrically insulating properties. Irradiation with medium-wave infrared rays allows silicon particles to be heated intensely over a short heating distance, for example, to a temperature exceeding 150°C, thereby increasing their electrical conductivity. In contrast, glass and plastic particles are not heated as much, for example, only to just under 100°C.

[0044] Furthermore, medium-wave infrared radiation has the property of coupling directly into water molecules. This results in efficient drying of the material mixture and thus a reduction in the conductivity of glass and plastic. Accordingly, the first infrared emitter 3 causes the material mixture to dry.

[0045] The first infrared emitter 3 is located at a distance of approximately 5 to 10 cm from the first

[0046] Vibratory conveyor 2 is positioned and irradiates the material mixture with medium-wave infrared radiation with a wavelength of 2,600 nm to 3,300 nm. After the irradiation of the material mixture by the first infrared emitter 3, the actual electrostatic separation process takes place to separate the silicon particles from the material mixture.

[0047] For this purpose, the material mixture is passed by a first corona electrode 4 to electrostatically charge it. A voltage of 10 kV to 30 kV is applied to the first corona electrode 4.

[0048] The material mixture is then applied to a first grounded electrode 5. The silicon particles in the material mixture transfer a large portion of their absorbed charge to the first grounded electrode 5, preventing them from adhering to it. The rotation of the first grounded electrode 5 and the resulting centrifugal force cause the silicon particles to detach from it. The glass and plastic particles are unable to transfer their charge to the grounded electrode 5, or can only do so very slowly, and thus remain adhered to it.

[0049] A first static electrode 6 generates an electric field between the first grounded electrode 5 and the first static electrode 6. The first static electrode 6 has the opposite polarity and exerts an attractive force on the silicon particles, deflecting them. Due to centrifugal force and the attractive force of the static electrode 6, the silicon particles follow a trajectory that separates them from the glass and plastic particles.

[0050] The temperature of the silicon particles was selectively increased by the first infrared emitter 3. At an increased temperature, the silicon particles' capacity to hold a charge increases. This makes it possible to increase the voltage applied during the subsequent electrostatic separation process by the first static electrode 6, thereby charging the particles of the material mixture more strongly. As a result, improved separation efficiency (i.e., better quality of the separated fractions) and a higher yield (i.e., a higher weight fraction of silicon particles) can be achieved during electrostatic separation. This enables improved separation of the silicon particles from the material mixture comprising silicon, glass, and plastic.

[0051] The first grounded electrode 5 and the first static electrode 6 are designed as roller electrodes. The first grounded electrode 5 rotates during operation. The first static electrode 6 can also rotate for cleaning purposes. Each electrode is equipped with a brush 7 to remove any particles adhering to the electrodes 5 and 6.

[0052] The device incorporates several splitters 8 that guide the material mixture. These splitters 8 make it possible to direct individual particles at specific points, thereby achieving a higher separation efficiency in electrostatic separation.

[0053] The electrostatic separation performed by the first corona electrode 4, the first grounded electrode 5, and the first static electrode 6 constitutes a first separation stage. In the first separation stage, the material mixture is divided into a non-conducting fraction and a conducting fraction. In the device shown in Fig. 1, the particles of the non-conducting fraction are directed to the left, while the particles of the conducting fraction are directed to the right.

[0054] Electrostatic separation processes typically do not achieve perfect separation of silicon particles from a material mixture comprising silicon, glass, and plastic particles. One source of error can be that silicon particles are arranged on top of glass or plastic particles when they are placed on the grounded electrode 5. As a result, these silicon particles cannot transfer their charge to the grounded electrode 5, or can only do so very slowly, and end up in the non-conducting fraction. Alternatively, glass or plastic particles can lie on top of silicon particles if they are located in the electric field between the grounded electrode 5 and the static electrode 6. This can cause these glass or plastic particles to be carried along by silicon particles into the conductive fraction. For this reason, it may be advantageous to employ a multi-stage separation process.

[0055] The device shown in Fig. 1 includes a second separation stage for the particles of the non-conductor fraction. Alternatively or additionally, it would also be possible to provide the second separation stage for the particles of the conductor fraction.

[0056] In the second separation stage, the process described above is repeated. First, the particles are placed on a second vibratory conveyor 2, which distributes the particles as evenly as possible. A second infrared emitter 3 irradiates the particles with medium-wave infrared radiation to increase the conductivity of the silicon particles and to dry the particles of the material mixture.

[0057] The particles are then electrically charged by a second corona electrode 4. Afterwards, the particles come into contact with the second grounded electrode 5. The glass and plastic particles cannot transfer their charge to the second grounded electrode 5, or only very slowly, and remain at least partially adhered there until they are removed by the brush 7. A second static electrode 6 generates an electric field between the second grounded electrode 5 and the second static electrode 6. The second static electrode 6 has the opposite polarity and exerts an attractive force on the silicon particles, deflecting them so that they are separated from the glass and plastic particles.

[0058] This second separation stage allows for the recovery of silicon particles that ended up in the non-conductor fraction during the first separation stage. As a result, the second separation stage increases the yield of the separation process.

[0059] In the second separation stage, the heating power generated by the second infrared emitter 3 and the electric field produced by the second static electrode 6 are set lower than in the first separation stage. In the second separation stage, the particles from the material mixture retain residual heat and charge from the first separation stage. If the voltage is not reduced in the second separation step, sparking and a momentary drop in the electric field between the second grounded electrode 5 and the second static electrode 6 can occur. This must be avoided.

[0060] After the second separation stage, the particles end up in collection containers not shown in Fig. 1, with one collection container for the non-conductor fraction, one collection container for the mixed fraction and one collection container for the conductor fraction.

[0061] 1 distribution funnel

[0062] 2 vibratory conveyors

[0063] 3 infrared heaters

[0064] 4 Corona electrode

[0065] 5 grounded electrode

[0066] 6 static electrode

[0067] 7 brush

[0068] 8 splinters

Claims

P a t e n t a n s p r ü c h e 1. Device for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture of solar cell residues with semiconductor particles, in particular silicon particles, and non-conducting particles, in particular plastic and / or glass particles, comprising a first corona electrode (4) for electrostatically charging the material mixture, a first grounded electrode (5) for discharging the semiconductor particles contained in the material mixture, and a first static electrode (6) for generating an electric field between the first grounded electrode (5) and the first static electrode (6), characterized in that a first infrared emitter (3) is provided for irradiating the material mixture with medium-wave infrared radiation, wherein the first infrared emitter (3) is arranged such that the material mixture passes the first infrared emitter (3) in front of the first corona electrode (4) during operation.

2. Device according to claim 1, characterized in that the first infrared emitter (3) is configured to irradiate the material mixture with medium-wave infrared radiation of 1,600 nm to 5,000 nm, in particular of 1,900 nm to 4,500 nm, particularly preferably of 2,300 nm to 4,000 nm and further preferably of 2,500 nm to 3,000 nm.

3. Device according to claim 1 or 2, characterized in that the first infrared emitter (3) and a first vibratory conveyor (2) are located at a distance of 1 cm to 50 cm, in particular from 1.5 cm to 40 cm, preferably from are arranged between 2 cm and 30 cm, particularly preferably between 2.5 cm and 20 cm and more preferably between 3 cm and 10 cm.

4. Device according to one of the preceding claims, characterized in that the first corona electrode (4) and the first vibratory conveyor (2) are arranged at a distance of at least 3°cm, preferably at least 7°cm and particularly preferably at least 10°cm.

5. Device according to one of the preceding claims, characterized in that the first infrared emitter (3) has a power output of 1 kW to 6 kW per 100 kg / h of material mixture, preferably 2 kW to 5 kW per 100 kg / h of material mixture and particularly preferably 2.5 kW to 3.5 kW per 100 kg / h of material mixture.

6. Device according to one of the preceding claims, characterized in that the first grounded electrode (5) and / or the first static electrode (6) are designed as roller electrodes, wherein preferably a brush (7) is provided on the first grounded electrode (5) and / or the first static electrode (6) for separating particles of the material mixture adhering to the electrodes (5, 6).

7. Device according to one of the preceding claims, characterized in that at least one splitter (8) is provided for directing the material mixture.

8. Device according to one of the preceding claims, characterized in that a second corona electrode (4) is provided for electrostatic charging of the The material mixture comprises a second grounded electrode (5) for discharging the semiconductor particles contained in the material mixture, a second static electrode (6) for generating an electric field between the second grounded electrode (5) and the second static electrode (6), and a second infrared emitter (3), wherein the corona electrodes (4), the grounded electrodes (5), the static electrodes (6) and the infrared emitters (3) are arranged such that the separation of the semiconductor particles from the material mixture takes place in two stages.

9. Method for the electrostatic separation of semiconductor particles, in particular silicon particles, from a material mixture of solar cell residues with semiconductor particles, in particular silicon particles, and non-conductor particles, in particular plastic and / or glass particles, preferably with a device according to one of claims 1 to 8, comprising the following steps: Provision of a material mixture comprising particles of a first material and at least one second material, wherein the first material is a semiconductor, in particular silicon, and the second material is a non-conductor, in particular plastic and / or glass, Irradiation of the material mixture with medium-wave infrared radiation using an infrared emitter (3), Charging the material mixture with a corona electrode (4), passing the material mixture past a grounded electrode (5) and generating an electric field by a static electrode (6).

10. Method according to claim 9, characterized in that the irradiation of the material mixture with medium-wave infrared radiation in a range of 1,600 nm to 5,000 nm, in particular from 1,900 nm to 4,500 nm, particularly preferably from 2,300 nm to 4,000 nm and further preferably from 2,500 nm to 3,000 nm.

11. Method according to claim 9 or 10, characterized in that the semiconductor particles are heated by irradiation with medium-wave infrared radiation to a temperature of 30°C to 140°C, preferably 50°C to 130°C, particularly preferably 70°C to 125°C and further preferably 90°C to 120°C.

12. Method according to one of claims 9 to 11, characterized in that the material mixture provided is solar module waste with silicon particles.

13. Method according to any one of claims 9 to 12, characterized in that the provided material mixture has a moisture content of up to 3 wt.%, preferably up to 2 wt.%.

14. Method according to any one of claims 9 to 13, characterized in that the material mixture is provided in a particle size of 40 pm to 3 mm.

15. Method according to one of claims 9 to 14, characterized in that a voltage of 10 kV to 30 kV is applied to the static electrode (6) and / or to the corona electrode (4).

16. Method according to one of claims 9 to 15, characterized in that the electrostatic separation is carried out in multiple stages, in particular in two stages.

17. Method according to claim 16, characterized in that the heating power generated by the infrared emitter (3) and / or the electric field generated by the static electrode (6) is set lower in a downstream stage than in an upstream stage.

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