EP4626619A1

EP4626619A1 - A method and apparatus for separating photovoltaic module materials

Info

Publication number: EP4626619A1
Application number: EP23895582.7A
Authority: EP
Inventors: Yansong SHEN; Yuting ZHUO; Chengsun HE
Original assignee: NewSouth Innovations Pty Ltd
Current assignee: NewSouth Innovations Pty Ltd
Priority date: 2022-11-30
Filing date: 2023-11-24
Publication date: 2025-10-08
Also published as: CN120303069A; JP2026500487A; WO2024113000A1; AU2023404644A1

Abstract

A method of separating materials of a photovoltaic (PV) module, and associated apparatus, is disclosed, the method comprising: providing at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion; introducing a load to the receiving portion, the load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material of the photovoltaic module and the second load portion comprises fragments of a second material of the photovoltaic module, the second material being a different type of material from the first material; adding one or more sieving aids to the receiving portion; agitating the at least one sieve, wherein the one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

Description

A method and apparatus for separating photovoltaic module materials

Cross reference to related application

[0001] This application claims priority to Australian provisional patent application no. 2022903639, filed 30 November 2022, the entire contents of which is incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to a method for separating materials and an associated apparatus. In particular, although not necessarily exclusively, the present disclosure relates to a method and apparatus for separating materials of photovoltaic modules, e.g., for recycling purposes.

Background

[0003] Photovoltaic (PV) modules, also known as solar panels, function to convert sunlight to electrical energy and as such are a valuable alternative to the use of fossil fuels for energy generation. PV modules typically include a solar cell layer including PV silicon wafer encapsulated between two protective sheets, the protective sheets being held in place on the PV silicon wafer by encapsulant layers such as ethylene-vinyl acetate (EVA) layers. The solar cell layer, protective sheets and encapsulant layers are typically set within a frame such as an aluminium frame. Metallization elements, acting as electrical conductors, are typically screen printed on the surface of the PV silicon wafer. One or both of the protective sheets typically comprises glass.

[0004] Due to the defects associated with natural wear of PV modules, such as detachment of layers and bum markings, the average life of a PV module is limited. PV modules that have reached their end of life must be disposed of and replaced. There is currently no standard procedure for the disposal of PV module waste and in most regions the waste becomes landfill.

[0005] Current processes used to recycle the materials of PV modules involve disassembly of the aluminium frame and delamination of the protective sheet and encapsulant layers using mechanical, thermal, and/or chemical methods. The disassembly and delamination processes often result in the damage and breakage of glass and PV silicon wafer, causing fragments of both materials to mix together. The fragments of glass and PV silicon wafer materials in the mixture are difficult to separate and therefore recycle. Current techniques used to separate the fragments of material include electrostatic separation and density separation, for example, which techniques attempt to separate the fragments based on differences in their physical properties.

[0006] In an electrostatic separation technique, materials are sorted based on the difference in their conductivity and therefore electrostatic properties. A PV solar module is shredded into fine particles and then fed into a roller-type separator. The particles are differently charged upon physical contact with a roller, which results in differences in falling trend of the particles from the roller, allowing separation of materials. Although the electrostatic separation method has great potential in dealing with large volumes of waste, it is relatively ineffective in separating glass from other conductive or semiconductive particles due to the relatively heavy weight of glass particles that means the momentum gained by the glass particles during rotation is superior to the influence of electrostatic forces.

[0007] Density separation segregates materials based on their mass-volume ratio. The PV solar module is shredded into fine particles and fed into the density separation equipment that includes a fluid. Separation of materials is achieved by using a fluid of intermediate density so that the particles of material having a first density range will float in the fluid and particles of material having a second density range will sink in the fluid. Water is one of the most commonly used fluids in the application of density separation. However, in the recycling of PV modules, water is no longer an appropriate and applicable solution since most of the materials contained in the PV modules have a relative density greater than 1. For example, the relative density of silicon, glass, aluminium, copper, and silver are 2.33, 2.5, 2.7, 8.9, and 10.4, respectively. Using other high-density fluids as the intermediate fluid is also possible, but it can significantly increase the operational cost and risk of the separation process in PV recycling.

[0008] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Summary

[0009] According to one aspect, the present disclosure provides a method of separating materials of a photovoltaic (PV) module, comprising: providing at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion; introducing a load to the receiving portion, the load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material of the photovoltaic module and the second load portion comprises fragments of a second material of the photovoltaic module, the second material being a different type of material from the first material; adding one or more sieving aids to the receiving portion; agitating the at least one sieve, wherein the one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

[0010] In some embodiments, the agitating of the at least one sieve is such that a part of the first load portion passes from the receiving portion through the sieving screen to the collection portion that is greater in size than any part of the second load portion that passes from the receiving portion through the sieving screen to the collection portion.

[0011] In some embodiments, the agitating of the at least one sieve is such that a major part of the first load portion passes from the receiving portion through the sieving screen to the collection portion, and a major part of the second load portion remains in the receiving portion.

[0012] In some embodiments, the major part of the first load portion comprises at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the first load portion. [0013] In some embodiments, the major part of the second load portion comprises at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the second load portion.

[0014] In some embodiments, the reduction in size of the plurality of fragments of the first material to below the aperture size is faster than any reduction in size of a plurality of fragments of the second material to below the aperture size.

[0015] In some embodiments, one or more of the sieving aids has the shape of a ball, a sphere, an ellipsoid, a cube, a cuboid, a cylinder, a cone or a pyramid.

[0016] In some embodiments, one or more of the sieving aids comprises stainless steel, rubber, plastic or ceramic.

[0017] In some embodiments, the adding of the one or more sieving aids to the receiving portion comprises adding at least 2, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 40, at least 50, at least 60, at least 100, at least 200, at least 500, at least 1000, at least 10000, between 2 and 10000, between 10 and 1000, between 100 and 500, between 500 and 1000, between 200 and 800, between 2 and 100, between 5 and 75, or between 10 and 60, sieving aids to the receiving portion.

[0018] In some embodiments, the fragments of the first material are fragments of photovoltaic silicon wafer of the PV module.

[0019] In some embodiments, the first load portion comprises metallization elements, or fragments of metallization elements, of the photovoltaic module, that are attached to or associated with the fragments of photovoltaic silicon wafer.

[0020] In some embodiments, the metallization elements comprise one or more of the following materials: silver, aluminium, tin, copper, zinc or lead.

[0021] In some embodiments, the fragments of the second material are fragments of glass of the photovoltaic module.

[0022] In some embodiments, the agitating of the at least one sieve comprises agitating the sieve intermittently.

[0023] In some embodiments, the agitating of the at least one sieve intermittently comprises agitating the sieve continuously during each of a plurality of first time periods, wherein successive first time periods of the plurality of first time periods are each separated by a respective second time period during which the sieve is substantially not agitated.

[0024] In some embodiments, during the first time period the one or more sieving aids undergo vibrational movement within the receiving portion to mechanically interact with the load.

[0025] In some embodiments, during the second time period the vibrational movement of the one or more sieving aids is disrupted and the sieving aids move substantially horizontally within the receiving portion.

[0026] In some embodiments the first time period is one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes; and the second time period is one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes.

[0027] In some embodiments, a total time period of agitation, that is the sum of the first time periods, is at least 1 minute, at least 2 minutes, at least 3 minutes, at least 4 minutes, at least 5 minutes, at least 6 minutes, at least 7 minutes, at least 8 minutes, at least 9 minutes, at least 10 minutes, at least 15 minutes, at least 20 minutes, at least 30 minutes, or at least 1 hour.

[0028] In some embodiments, the first time period is at least 3 seconds, the second time period is at least 3 seconds and the total time period of agitation is at least 5 minutes.

[0029] In some embodiments, the agitating of the at least one sieve is such that the sieve has an amplitude of vertical movement of at least 1 mm, at least 1.5 mm, at least 2 mm, at least 2.5 mm, at least 3 mm at least 5 mm, at least 10 mm, at least 20 mm, or at least 50 mm.

[0030] In some embodiments, the method comprises providing a plurality of the sieves in a vertically stacked arrangement, wherein the receiving portion of at least one lower sieve of the plurality of sieves provides the collection portion for at least one higher sieve of the plurality of sieves that is located above the at least one lower sieve. [0031] In some embodiments, the sieving screens of the plurality of sieves have decreasing aperture sizes from a top to the bottom of the vertically stacked arrangement of the plurality of sieves.

[0032] In some embodiments, one or more sieving aids are added in the receiving portions of two or more of the plurality of sieves.

[0033] In some embodiments, a quantity of the sieving aids and/or physical parameters of the sieving aids added in each of the receiving portions is different.

[0034] According to one aspect of the present disclosure, there is provided photovoltaic (PV) module material separation apparatus, comprising: at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion, wherein the receiving portion is adapted to receive a load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material of the photovoltaic module and the second load portion comprises fragments of a second material of the photovoltaic module, the second material being a different type of material from the first material; one or more sieving aids configured to be received in the receiving portion; an agitation mechanism configured to agitate the at least one sieve such that one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

[0035] The PV module material separation apparatus may be used, for example, in the method describe above with respect to the preceding aspect, and any one or more of the components of the apparatus may be configured as described with respect to the preceding aspect.

[0036] Although the method and apparatus is described above in relation to separation of materials of a photovoltaic module, the method and apparatus may be used for separation of other materials. [0037] Following from this, according to one aspect, the present disclosure provides a method of separating materials, comprising: providing at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion; introducing a load to the receiving portion, the load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material and the second load portion comprises fragments of a second material, the second material being a different type of material from the first material; adding one or more sieving aids to the receiving portion ; agitating the at least one sieve, wherein the one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

[0038] Moreover, according to another aspect of the present disclosure, there is provided material separation apparatus, comprising: at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion, wherein the receiving portion is adapted to receive a load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material and the second load portion comprises fragments of a second material, the second material being a different type of material from the first material; one or more sieving aids configured to be received in the receiving portion; an agitation mechanism configured to agitate the sieve such that one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

[0039] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Brief Description of Drawings

[0040] By way of example only, embodiments are now described with reference to the accompanying drawings, in which:

[0041] Fig. 1 shows an exploded view of a PV module;

[0042] Fig. 2 shows a flowchart of a method of separating materials of a PV module according to an embodiment of the present disclosure;

[0043] Fig. 3 shows PV module material separation apparatus according to an embodiment of the present disclosure including a load in a receiving portion of a sieve of the apparatus;

[0044] Fig. 4 shows the apparatus of Fig. 3 after agitation of the sieve;

[0045] Fig. 5 shows PV module material separation apparatus according to an embodiment of the present disclosure including a load in a receiving portion of a sieve of the apparatus;

[0046] Fig. 6 shows different sieving aids according to embodiments of the present disclosure;

[0047] Figs. 7A and 7B show images of fragments of material in a 5 mm sieve portion following an initial sieving process without the use of sieving aids and a sieving process with the use of sieving aids, respectively;

[0048] Figs. 8A and 8B show images of fragments of material in a 3. 15 mm sieve portion following an initial sieving process without the use of sieving aids and a sieving process with the use of sieving aids, respectively;

[0049] Figs. 9A and 9B show images of fragments of material in a 1 mm sieve portion following an initial sieving process without the use of sieving aids and a sieving process with the use of sieving aids, respectively; and

[0050] Fig. 10 shows an image of concentrated PV silicon wafer fragments in a 0.5 mm sieve portion following a sieving process with the use of sieving aids. Description of Embodiments

[0051] One or more embodiments of the present disclosure provide methods and apparatus that separate materials of a PV module, e.g. as part of a recycling process.

[0052] An example of a PV module 100, that may be subject to methods and apparatus of the present disclosure, is illustrated in Fig. 1. The PV module 100 includes a solar cell layer 110 (which layer may comprise one or more solar cells), the solar cell layer comprising PV silicon wafer. First and second protective sheets 120, 130 are positioned either side of the solar cell layer and fixed to opposite sides of the solar cell layer 100 using first and second encapsulant layers 140, 150, respectively. The first and second encapsulant layers may be ethylene -vinyl acetate (EVA) layers, although other thermoplastics may be used as encapsulant. The assembly of the solar cell layer 110, first and second protective sheets 120, 130, and encapsulant layers 140, 150 is held in a frame 160, such as an aluminium frame.

[0053] One or both of the first and second protective sheets 120, 130 may comprise glass, allowing sunlight to be transmitted through the glass to the solar cell layer 100. The glass may comprise one of soda-lime glass, borosilicate glass, and lead crystal glass or any other type of glass typically used in PV modules. The glass may be tempered glass.

[0054] Metallization elements 115, such as busbars, conductive fingers and contacts, are attached to or otherwise associated with the PV silicon wafer of the solar cell layer 110 for the purpose of transferring electricity that is generated via the solar cell layer 110. The metallization elements 115 may comprise one or more of the following materials: silver, aluminium, tin, copper, zinc or lead, or any other materials that may be used as electrical conductors of a photovoltaic module to transfer electricity that is generated via the PV silicon wafer.

[0055] At the end of the life of the PV module 100 or otherwise, the PV module 100 may be disassembled, removing the frame 160 from the other components of the PV module 100. Subsequently, the protective sheets 120, 130 and encapsulant layers 140, 150 may be delaminated from solar cell layer 110 using mechanical, thermal, and/or chemical methods. The disassembly and/or delamination process often results in the damage and breakage of glass of at least one of the first and second protective sheets 120, 130 along with breakage of the PV silicon wafer, causing fragments of glass to mix with fragments of PV silicon wafer and potentially fragments of the associated metallization elements 115. Methods and apparatus according to embodiments of the present disclosure can be used to separate the fragments of the different materials, e.g. as part of a PV module recycling process or otherwise. The methods and apparatus may allow recovery, and may increase recycling yields, of materials such as silicon and/or any one or more metals that are present in PV modules.

[0056] With reference to Fig. 2, in a method 200 of separating materials of a PV module according to an embodiment of the present disclosure, at 210, a load, and one or more sieving aids, are added to a receiving portion of a sieve. The sieve comprises the receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to a collection portion. The load comprises a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material of the photovoltaic module and the second load portion comprises fragments of a second material of the photovoltaic module, the second material being a different type of material from the first material.

[0057] At 220, the sieve is agitated, wherein the one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size of the sieving screen.

[0058] The agitation of the sieve may be such that a part of the first load portion passes from the receiving portion through the sieving screen to the collection portion that is greater in total size than any part of the second load portion that passes from the receiving portion through the sieving screen to the collection portion. For example, the amount of the first load portion, by weight percentage (wt%) of the total first load portion introduced to the receiving portion, that passes through the sieving screen to the collection portion, may be greater than the amount of second load portion, by wt% of the total second load portion introduced to the receiving portion, that passes through the sieving screen to the collection portion.

[0059] The agitation of the sieve may be such that a major part of the first load portion may pass from the receiving portion through the sieving screen to the collection portion, and a major part of the second load portion may remain in the receiving portion. The major part of the first load portion may comprise at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the first load portion, and the major part of the second load portion may comprise at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the second load portion.

[0060] Figure 3 illustrates a PV module material separation apparatus 300 according to an embodiment of the present disclosure, which may be use to carry out the method described with respect to Fig. 2, for example, and optionally following disassembly and delamination of a PV module 100 of a type described above with respect to Fig. 1. The apparatus 300 includes a sieve 305 that has a receiving portion 310 and a sieving screen 320. A collection portion 330 of the apparatus 300 is located beneath the sieve 305. The sieving screen 320 includes a plurality of apertures 321, wherein fragments of material having a size below an aperture size of the plurality of apertures 321 can pass from the receiving portion 310 through the sieving screen 320 to the collection portion 330. In some embodiments, the collection portion 330 may be a pan of the sieving apparatus as illustrated in Fig. 3.

[0061] The apparatus 300 further includes an agitation mechanism 340 to agitate (e.g. vibrate) the sieve 305. The agitation mechanism 340 may include a vibrating plate 341 and motor 342 to vibrate the vibrating plate 341. The agitation mechanism may vibrate the sieve 305 vertically and/or horizontally. Additionally or alternatively, the agitation mechanism 340 may agitate the sieve 305 by exerting a circular motion and/or by applying tapping to the sieve 305. The agitation mechanism 340 may be positioned under the sieve 305 although in alternative embodiments it may be located above or to the side of the sieve 305. The agitation may agitate at least the receiving portion 310 and sieving screen 320 of the sieve 305. A controller 343 may be associated with the agitation mechanism to control the motor 342 and therefore agitation parameters such as amplitude of vibration and duration. Some or all of the apparatus 300 may be provided by a commercially available vertical sieve shaker, horizontal sieve shaker, tap shaker, or rotational tap shaker, for example. The agitation of the sieve 305 may be such that the sieve 305 has an amplitude of vertical movement (and/or horizontal movement) of at least 1 mm, at least 1.5 mm, at least 2 mm, at least 2.5 mm, at least 3 mm, at least 5 mm, at least 10 mm, at least 20 mm, or at least 50 mm, for example. The amplitude of vertical movement (and/or any other movements) of the sieve 305 may be increased when the method is performed using larger-scale sieves that can accommodate a larger load, for example.

[0062] In Figure 3, a load 350 comprising a first load portion 360 and a second load portion 370 is illustrated after being added to the receiving portion 310 of the sieve 305. The first load portion 360 comprises fragments of a first material 361 of the photovoltaic module and the second load portion comprises fragments of a second material 362 of the photovoltaic module, the second material being a different type of material from the first material. The fragments of the first material 361 may be fragments of PV silicon wafer and the fragments of second material 362 may be fragments of glass (fragments of a glass layer). In addition to the fragments of PV silicon wafer, the first load portion 360 may comprise fragments of a third material 363 which may comprise metallization elements 363 as described with respect to Fig. 1.

[0063] In addition to the load 350, one or more sieving aids 380, and in this instance a plurality of sieving aids 380, are also added to the receiving portion 310 of the sieve 305, before or after addition of the load 350. The sieving aids 380 are additives to the sieving process that are not part of the PV module that is being processed. During agitation of the sieve 305, the sieving aids 380 are configured to mechanically interact with (e.g., strike, crush, pound and/or pulverise) the load 350 to assist in a reduction in size of, at least, a plurality of the fragments of the first material 361 and optionally also the third material 363, to below the aperture size. The reduction in size of the plurality of fragments of the first material 361 and optionally also the third material 363, to below the aperture size, may be faster than any reduction in size of a plurality of fragments of the second material 362 to below the aperture size. In general, the fragments of the first material 361 (and optionally the third material 363) may be more readily reduced in size than the fragments of the second material 362, e.g. as a result of the fragments of the first material 361 (and optionally the third material 363) being more susceptible to breakage as a result of mechanically interacting with the sieve 305 and sieving aids 380 than the fragments of the second material 362. However, this may not be necessary in instances where, before mechanically interacting with the sieving aids 380, the fragments of first material 361 (and optionally third material 363) are already closer to the threshold size than the fragments of the second material 362. [0064] As shown in Fig. 4, agitation of the sieve 305 causes a part of the first load portion 360 (including the fragments of the first material 361 and optionally fragments of the third material 363) to pass from the receiving portion 310 through the sieving screen 320 to the collection portion 330 that is greater in total size than any part of the second load portion (including fragments of the second material 362) that passes from the receiving portion 310 through the sieving screen 320 to the collection portion 330. For example, the amount of the first load portion 360, by weight percentage (wt%) of the total first load portion added to the receiving portion 310, that passes through the sieving screen 320 to the collection portion 330, may be greater than the amount of second load portion 370, by wt% of the total second load portion added to the receiving portion 310, that passes through the sieving screen 320 to the collection portion 330.

[0065] The agitation of the sieve 305 may be such that a major part of the first load portion 360 may pass from the receiving portion 310 through the sieving screen 320 to the collection portion 330, and a major part of the second load portion 370 may remain in the receiving portion 310. The major part of the first load portion 360 may comprise at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the first load portion 360, and the major part of the second load portion 370 may comprise at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the second load portion.

[0066] A variety of different sieving parameters may be selected to optimise the desired reduction in size of the fragments of first material 361, and optionally also the third material 363, so that first load portion passes more readily, in comparison to the second load portion, from the receiving portion 310 through the apertures 321 of the sieving screen 320 to the collection portion 330. Sieving parameters that are selected may include the quantity of sieving aids 380 added to the receiving portion 310, the weight, density and/or size (e.g. diameter or volume) of the sieving aids 380, the shape of the sieving aids 380, the material of the sieving aids 380 or otherwise. The parameters chosen may be dependent on factors such as the weight and/or constituents of the load 350 and the dimensions of the sieve 305, for example.

[0067] For example, one or more of the sieving aids 380 may have, with reference to Fig.6, the shape of a ball (including a sphere 381 or ellipsoid 382), a cube 383, a cuboid 384, a cylinder 385, a cone 386 or a pyramid 387. As another example, one or more of the sieving aids 370 may comprise stainless steel, rubber, plastic, ceramic or any other material that may allow the desired size reductions of the different materials to be achieved. The quantity of sieving aids 380 added to the receiving portion 310 may be at least 2, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 40, at least 50, at least 60, at least 100, at least 200, at least 500, at least 1000, at least 10000, between 2 and 10000, between 10 and 1000, between 100 and 500, between 500 and 1000, between 200 and 800, between 2 and 100, between 5 and 75, or between 10 and 60, sieving aids 380, for example. The diameter of one or more of the sieving aids 380 (e.g. when having the shape of a ball or sphere) may be at least 5 mm, at least 10 mm, at least 15 mm, at least 20 mm, at least 50 mm, at least 100 mm, between 5 and 100 mm, between 10 and 50 mm, between 3 and 20 mm, between 4 and 15 mm, or between 5 and 10 mm, for example. A greater quantity of sieving aids 380, and/or sieving aids 380 having a greater size, diameter, weight and/or density, may be added to the receiving portion of larger-scale sieves that can accommodate a larger load, for example.

[0068] In the method and apparatus described above, the agitating of the sieve 305 may comprise agitating the sieve 305 intermittently. Agitating the sieve 305 intermittently may comprise agitating the sieve 305 continuously during each of a plurality of first time periods, wherein successive first time periods of the plurality of first time periods are each separated by a respective second time period during which the sieve is substantially not agitated.

During the first time period the one or more sieving aids 380 may undergo vibrational movement within the receiving portion 310 (e.g. vertical and/or horizontal oscillatory movement within the receiving portion 310) to mechanically interact with the load 350. During the second time period the vibrational movement of the one or more sieving aids 380 may be disrupted and the sieving aids 380 may move substantially horizontally within the receiving portion 310. This may enhance contact between the sieving aids 380 and the fragments of first material 361 and optionally the third material 363, e.g., by allowing repositioning of the sieving aids 380 to different areas within the sieve during the second time period.

[0069] The first time period may be one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes, for example; and the second time period may be one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes, for example. The first and second time periods may be increased when the method is performed using larger-scale sieves that can accommodate a larger load, for example.

[0070] A total time period of agitation, that is the sum of the first time periods, may be at least 1 minute, at least 2 minutes, at least 3 minutes, at least 4 minutes, at least 5 minutes, at least 6 minutes, at least 7 minutes, at least 8 minutes, at least 9 minutes, at least 10 minutes, as least 20 minutes, at least 30 minutes, or at least 1 hour, for example. The first time period may be at least three seconds, the second time period may be at least 3 seconds and the total time period of agitation may be at least 5 minutes, for example. The total time period of agitation may be increased when the method is performed using larger-scale sieves that can accommodate a larger load, for example.

[0071] In the apparatus of Figs. 3 and 4, a single sieve 305 is provided having a receiving portion 310 and a sieving screen 320, and located above a single collection portion 330 only. In alternative embodiments, as illustrated in Fig. 5, apparatus 400 may be provided that includes a plurality of sieves 405a, 405b, 405c that each include a respective receiving portion 410a, 410b, 410c and a respective sieving screen 420a, 420b, 420c and which are each located above a respective collection portion 430a, 430b, 430c. The sieves 405a, 405b, 405c are stacked vertically on top of each other above an agitation mechanism 440 that may be operable to agitate all of the sieves 405a, 405b, 405c at the same time, and that may agitate the sieves 405, 405b, 405c in the same or a similar manner to the agitation mechanism 340 of the apparatus 300 discussed above. The sieving screens 420a, 420b, 420c may have apertures of decreasing sizes from the highest to the lowest sieves 405a, 405b, 405c of the stack. In this arrangement, one or more receiving portions 410b, 410c of lower sieves 405b, 405c in the stack may act individually, or in combination, as one or more collection portions 430a, 430b for the sieves 405a, 405b that are located higher up the stack. A pan may act as a collection portion 430c for the lowest sieve 403c. Some or all of the apparatus 400 may be provided by a commercially available vertical sieve shaker, horizontal sieve shaker, tap shaker, or rotational tap shaker, for example. One or more sieving aids 480 can be added to the receiving portions 410a, 410b of one or more of the sieves 405a, 405b. A quantity of the sieving aids 480 and/or physical parameters of the sieving aids added in each of the receiving portions 410a, 410b may be the same or different. For example, sieving aids 480 in higher quantity and/or with smaller size (diameter) may be provided in the receiving portion 410b of one or more lower sieves 405b compared to one or more higher sieves 405a.

Experimental Examples

[0072] Loads were obtained following disassembly and thermal delamination of PV modules. The loads each including fragments of broken glass layers along with fragments (chips) of PV silicon wafer and associated metallization elements.

[0073] One of the loads was sieved using a vibratory sieve shaker (Rctsch™ AS200 vibratory sieve shaker) utilising a vertical stack of sieves of decreasing sieving aperture size from top to bottom (10 mm, 5 mm, 3.15 mm, 1 mm, 0.5 mm, 0.15 mm and 0.075 mm) located above a pan and a vibration mechanism. Sieving was carried out at 1.5 mm vertical vibration amplitude for a single continuous sieving time of 3 minutes. No sieving aids were used in the sieving process. The separation by weight of fractions of the load within each sieve after the sieving process was complete is listed, along with estimated silver content of each fraction, in Table 1 below. The fractions in the sieves with the four largest aperture sizes (10 mm, 5 mm, 3.15 mm and 1 mm) were each observed to contain a large number of fragments of PV silicon wafer mixed with broken glass, with sieves with smaller apertures collecting PV silicon wafer powders representing roughly 2.5%wt of the original load.

Table 1 [0074] A load was sieved using a vibratory sieve shaker (Rctsch™ AS200 vibratory sieve shaker) utilising the same vertical stack of sieves of decreasing sieving aperture size from top to bottom (10 mm, 5 mm, 3.15 mm, 1 mm, 0.5 mm, 0.15 mm and 0.075 mm) located above a pan and vibration mechanism, but with sieving aids added to the sieves with the four largest aperture sizes (10 mm, 5 mm, 3.15 mm and 1 mm; which were the sieve portions observed to include a large number of fragments of PV silicon wafer mixed with broken glass after the sieving process of the previous example). Sieving was carried out with the following parameters: (A) 1.5 mm vertical vibration amplitude for intermittent 3 second time periods, separated by periods of no sieving, across a total of 5 minutes of sieving time or (B) 2.0 mm vertical vibration amplitude for 5 second time periods, separated by periods of no sieving, across a total of 5 minutes of sieving time.

[0075] The quantity, diameter and material of the sieving aids that were used in each sieve, along with the weight of the portion of the load in each sieve before and after the sieving process, and an estimated separation efficiency of the fragments of glass from the fragments of PV silicon waver and associated metallization element, are listed in Table 2A and 2B below. Tables 2A and 2B provide results when the sieving parameters (A) and (B) discussed above were applied, respectively.

Table 2A

Table 2B

[0076] The results indicate that the use of sieving aids significantly enhances the separation efficiency of the sieving process with substantially 100% of all PV silicon wafer fragments, and associated metallization elements, to have been sufficiently reduced in size by mechanical interaction with the sieve and sieving aids, in order to pass through the sieving screens with 10 mm and 5 mm aperture size, leaving glass fragments only in these sieve portions. Moreover, when higher vertical vibration amplitude was used and applied for longer intermittent time periods, similar separation efficiencies were achieved in the sieve portions with 3.15 mm and 1 mm apertures size, resulting in an estimated 98% of PV silicon wafer fragments to be recoverable using the process.

[0077] In a further experimental example, a similar experimental arrangement was utilised, again in respect to a load resulting from a thermal delamination process of a PV module. After an initial sieving process without use of sieving aids, the weight of fractions of the load distributed across the different sieves were determined and are listed in the second column of Table 3 below. Subsequently, a sieving process was applied to the fractions of the load utilising sieving conditions and sieving aids with parameters (quantity, diameter and material) as listed in Table 4 below. Following completing of this sieving process, the weight of fractions of the load distributed across the different sieves were determined and are listed in the third column of Table 3 below.

Table 3

Table 4

[0078] By comparing the particle size distribution before and after applying the proposed sieving process that uses sieving aids, it can be concluded that most of the large fragments of PV silicon wafer (around 14g) were originally contained in the 1 mm, 3.15 mm, and 5 mm sieves, and these fragments were crushed by the sieving aids during the sieving process. Figs. 7A, 8 A and 9 A show the separation performance of the initial sieving process (without use of sieving aids) for the 5 mm, 3.15 mm and 1 mm sieves, respectively. Figs. 7B, 8B and 9B show the separation performance of the sieving process (with use of sieving aids) for the 5 mm, 3.15 mm and 1 mm sieves, respectively. As shown in Figs 7A and 7B, a greater portion of the fragments of PV silicon wafer 760 remain in the 5 mm sieve after the initial sieving process in comparison to the portion of fragments of PV silicon wafer that remain after the proposed sieving process, leaving only glass fragments 770 in the receiving portion. A similar finding is noted when comparing the proportion of the fragments of PV silicon wafer 860, 960 and the remaining fragments of glass 870, 970 following an initial sieving process and the proposed sieving process, as shown in Figs. 8A to 9B. A major portion of these fragments (around 10.8g) were concentrated into the 0.5mm sieve, as shown in Fig. 10.

[0079] Silver concentration provides an indicator of the separation efficiency, as silver is one of the most valuable materials contained in a load portion that includes typical PV silicon wafer. For this experimental example, around 191.2 mg of AgNOs can be extracted from this targeted load portion. About 33% of the silver content (62 mg) are contained within PV silicon wafer powders that originally have a particle size of less than 1 mm and can be easily collected and treated. Around 13 g of larger fragments of PV silicon wafer are concentrated in the lower sieves (0.5mm sieve, 0.075 mm sieve, etc.), and around 124.5 mg (65%) of AgNOs can be extracted therefrom. A small portion of fragments PV silicon wafer remains in the higher sieves after the sieving process, and around 4.7 mg (2%) of AgNO3 can be extracted from among these fragments.

[0080] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A method of separating materials of a photovoltaic (PV) module, comprising: providing at least one sieve and at least one collection portion, the sieve comprising a receiving portion and a sieving screen, the sieving screen including a plurality of apertures, wherein fragments of material having a size below an aperture size of the plurality of apertures can pass from the receiving portion through the sieving screen to the collection portion; introducing a load to the receiving portion, the load comprising a first load portion and a second load portion, wherein the first load portion comprises fragments of a first material of the photovoltaic module and the second load portion comprises fragments of a second material of the photovoltaic module, the second material being a different type of material from the first material; adding one or more sieving aids to the receiving portion; agitating the at least one sieve, wherein the one or more sieving aids mechanically interact with the load to assist in a reduction in size of a plurality of the fragments of the first material to below the aperture size.

2. The method of claim 1, wherein the agitating of the at least one sieve is such that a part of the first load portion passes from the receiving portion through the sieving screen to the collection portion that is greater in size than any part of the second load portion that passes from the receiving portion through the sieving screen to the collection portion.

3. The method of claim 1 or 2, wherein the agitating of the at least one sieve is such that a major part of the first load portion passes from the receiving portion through the sieving screen to the collection portion, and a major part of the second load portion remains in the receiving portion.

4. The method of claim 3, wherein the major part of the first load portion comprises at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the first load portion.

5. The method of claim 3 or 4, wherein the major part of the second load portion comprises at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% or at least 98wt%, of the second load portion.

6. The method of any one of the preceding claims, wherein the reduction in size of the plurality of fragments of the first material to below the aperture size is faster than any reduction in size of a plurality of fragments of the second material to below the aperture size.

7. The method of any one of the preceding claims, wherein one or more of the sieving aids has the shape of a ball, a sphere, an ellipsoid, a cube, a cuboid, a cylinder, a cone or a pyramid.

8. The method of any one of the preceding claims, wherein one or more of the sieving aids comprises stainless steel, rubber, plastic or ceramic.

9. The method of any one of the preceding claims, wherein adding of the one or more sieving aids to the receiving portion comprises adding at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 40, at least 50, at least 60, at least 100, at least 200, at least 500, at least 1000, at least 10000, between 2 and 10000, between 10 and 1000, between 100 and 500, between 500 and 1000, between 200 and 800, between 2 and 100, between 5 and 75, or between 10 and 60, sieving aids to the receiving portion.

10. The method of any one of the preceding claims, wherein the fragments of the first material are fragments of photovoltaic (PV) silicon wafer of the PV module.

11. The method of claim 10, wherein the first load portion comprises metallization elements, or fragments of metallization elements, of the photovoltaic module, that are attached to or associated with the fragments of PV silicon wafer.

12. The method of claim 11, wherein the metallization elements comprise one or more of the following materials: silver, aluminium, tin, copper, zinc and lead.

13. The method of any one of the preceding claims, wherein the fragments of the second material are fragments of glass of the PV module.

14. The method of any one of the preceding claims, wherein the agitating of the at least one sieve comprises agitating the sieve intermittently.

15. The method of claim 14, wherein agitating the at least one sieve intermittently comprises agitating the sieve continuously during each of a plurality of first time periods, wherein successive first time periods of the plurality of first time periods are each separated by a respective second time period during which the sieve is substantially not agitated.

16. The method of claim 15, wherein during the first time period the sieving aids undergo vibrational movement within the receiving portion to mechanically interact with the load.

17. The method of claim 15 or claim 16, wherein during the second time period the vibrational movement of the sieving aids is disrupted and the sieving aids move substantially horizontally within the receiving portion.

18. The method of claim 15, 16 or 17, wherein: the first time period is one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes; and the second time period is one of: at least 2 seconds, at least 3 seconds, at least 4 seconds, at least 5 seconds, at least 6 seconds, at least 7 seconds, at least 8 seconds, at least 9 seconds, at least 10 seconds, at least 20 seconds, at least 30 seconds, at least 50 seconds, at least 100 seconds, or at least 5 minutes.

19. The method of claim 18, wherein a total time period of agitation, that is the sum of the first time periods, is at least 1 minute, at least 2 minutes, at least 3 minutes, at least 4 minutes, at least 5 minutes, at least 6 minutes, at least 7 minutes, at least 8 minutes, at least 9 minutes, at least 10 minutes, at least 15 minutes, at least 20 minutes, at least 30 minutes, or at least 1 hour.

20. The method of claim 19, wherein, the first time period is at least three seconds, the second time period is at least 3 seconds and the total time period of agitation is at least 5 minutes.

21. The method of any one of the preceding claims, wherein the agitating of the at least one sieve is such that the sieve has an amplitude of vertical movement of at least 1 mm, at least 1.5 mm, at least 2 mm, at least 2.5 mm, at least 3 mm at least 5 mm, at least 10 mm, at least 20 mm, or at least 50 mm,.

22. The method of any one of the preceding claims, comprising providing a plurality of the sieves in a vertically stacked arrangement, wherein the receiving portion of at least one lower sieve of the plurality of sieves provides the collection portion for at least one higher sieve of the plurality of sieves that is located above the at least one lower sieve.

23. The method of claim 22, wherein the sieving screens of the plurality of sieves have decreasing aperture sizes from a top to the bottom of the vertically stacked arrangement of the plurality of sieves.

24. The method of claim 22 or 23, wherein one or more sieving aids are added to the receiving portions of two or more of the plurality of sieves.

25. The method of claim 24, wherein a quantity of the sieving aids and/or physical parameters of the sieving aids added to each of the receiving portions is different.