A method for separating elemental silicon from glass in a decommissioned photovoltaic module based on surface modification

Abstract

This invention belongs to the field of comprehensive utilization technology of secondary silicon resources, and discloses a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification. Crystalline silicon solar panels and glass fragments that have undergone pyrolysis treatment and had their EVA film removed are dried, crushed, ground, and sieved to prepare a slurry. Cu is then added sequentially to the resulting slurry. 2+ The slurry obtained from kerosene and No. 2 oil is subjected to flotation using conventional processes to obtain silicon concentrate and glass tailings. This invention innovatively proposes using kerosene as a collector. Through strong van der Waals forces and hydrogen bonds, kerosene molecules are physically adsorbed onto the surface of elemental silicon, Cu... 2+ As an activator, it undergoes dissociation and adsorption on the silicon surface, forming Cu–Si and O–Si double bonds, significantly increasing the number of surface active sites and promoting the adsorption behavior of kerosene on elemental silicon. The entire process has high recovery indicators, a simple flow, is easy to operate, has low production costs, and is environmentally friendly and energy-saving.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization technology of silicon secondary resources, and particularly relates to a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification. Background Technology

[0002] As the global energy system accelerates its transition towards low-carbon and renewable energy, solar photovoltaic (PV) power generation, as an important form of clean energy, is experiencing rapid growth, with its installed capacity continuously expanding. Driven by the "dual carbon" goal, renewable energy is gradually replacing traditional fossil fuels, and the energy landscape, including solar and wind power, is reshaping the global energy map. Crystalline silicon PV modules have long maintained a dominant position in the PV market due to their mature technology and high conversion efficiency, with approximately 95% of PV modules worldwide using crystalline silicon technology. However, with large-scale deployment, these modules will generate a large amount of decommissioned PV waste after their service life reaches approximately 25 years. It is projected that the number of decommissioned silicon-based modules will increase exponentially in the coming decades. The need for effective disposal and resource utilization of this massive amount of decommissioned PV modules has become an urgent issue for the circular development of the industry.

[0003] Retired photovoltaic modules are mainly composed of glass, aluminum frames, silicon wafers, EVA film, and other small amounts of metals, making them highly valuable and with significant recycling potential. Current research and industrial practice emphasize multiple separation methods, including mechanical, chemical, and pyrolysis, to achieve module layering and the recovery of valuable materials. Conventional technologies generally involve frame disassembly, heat treatment, or chemical leaching to remove the encapsulation layer, followed by the recovery of silicon wafers, precious metals, and other resources using physical or chemical methods. Pyrolysis and heat treatment processes can remove the organic EVA film, but high-temperature processing may generate destructive gases and cause glass breakage, while also consuming high amounts of heat energy, requiring substantial equipment investment, and having a significant environmental impact. Physical and mechanical separation methods, such as electrostatic separation and crushing and screening, can separate different components of the module to some extent, but they struggle to effectively separate high-purity silicon from glass, and are particularly difficult to handle cell fragments that have broken and become mixed with glass after pyrolysis. Chemical leaching separates metal components through acid-base reactions, but it suffers from high costs and secondary pollution in removing the encapsulation and separating the silicon / glass interface. Existing technologies often struggle to guarantee separation efficiency and resource recovery rates when dealing with silicon and glass powders mixed after pyrolysis. Furthermore, conventional methods often require complex process steps, high energy consumption, or environmental remediation facilities, which limits the scale of industrialization.

[0004] At the forefront of international photovoltaic recycling technology research and development, existing studies have proposed strategies to improve module delamination through pyrolysis combined with mechanical separation, chemical leaching, or auxiliary heating. However, most studies focus on EVA layer removal or silicon wafer integrity protection, and there is still insufficient research on how to effectively and selectively separate elemental silicon and glass under glass-doped conditions after pyrolysis. For example, one study proposed using microwave heating to assist in the separation of glass and silicon to improve glass removal efficiency before pyrolysis, but this method still relies on complex equipment control and has limitations in separating mixed fine powder systems.

[0005] Currently, no publicly available literature or known technology proposes a specific method for efficiently and selectively separating elemental silicon and glass powder during flotation by utilizing metal ions to regulate the surface activity of silicon in an aqueous slurry medium, selectively adsorbing non-polar collectors to enhance the hydrophobicity of silicon particles. This creates a technological gap in the field of photovoltaic module recycling and presents new challenges and development directions for the high-purity resource recovery of large-scale retired modules. The existing technologies generally cannot overcome the core problems of low separation efficiency of glass and silicon in the fragmented mixture after pyrolysis, high processing costs, and poor environmental performance. Therefore, new process technologies are still needed to improve separation efficiency, reduce energy consumption, and mitigate the environmental impact of the recycling process.

[0006] In summary, while existing technologies have explored various approaches to the stratification and recycling of valuable materials in decommissioned photovoltaic modules, they still exhibit significant shortcomings in processing the broken and mixed silicon and glass powders after pyrolysis. A separation method that is efficient, environmentally friendly, and industrially viable is lacking. Furthermore, current methods fail to effectively combine the chemical properties of the material surfaces with highly selective separation mechanisms to form a stable and repeatable recycling process. This technological gap is precisely the core technical problem that this solution aims to address. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a flotation method that is simple, low-cost, highly efficient and environmentally friendly, for the efficient recovery of high-purity elemental silicon from a mixture of pyrolyzed decommissioned photovoltaic modules, while simultaneously enriching glass powder.

[0008] To achieve the above objectives, the present invention adopts a technical solution: a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification, comprising the following steps:

[0009] Step 1: After the monocrystalline silicon solar panel and glass fragments that have undergone pyrolysis treatment and have had the EVA film removed are dried, crushed, ground, and sieved, a slurry is prepared and adjusted.

[0010] Step 2: Add Cu to the slurry obtained in Step 1. 2+ Mix the paste;

[0011] Step 3: Add kerosene to the slurry obtained in Step 2 to adjust the slurry;

[0012] Step 4: Add a foaming agent to the slurry obtained in Step 3 to adjust the slurry;

[0013] Step 5: The slurry obtained in Step 4 is subjected to flotation using conventional processes to obtain silicon concentrate.

[0014] Furthermore, the grinding and sieving in step one involves grinding the battery panel and glass fragments separately until 90% of the particles have a fineness of -74μm, or grinding the mixed mineral sample to a fineness of -200~325 mesh.

[0015] Furthermore, the slurry preparation in step one is as follows: 10g of a mixture of monocrystalline silicon solar panel powder and glass powder and 190mL of water are added to the flotation cell.

[0016] Furthermore, in step one, the pH adjustment of the slurry is achieved by using sodium hydroxide to adjust the pH of the solution to 8.0.

[0017] Furthermore, the slurry preparation time in step one is 3 minutes.

[0018] Furthermore, Cu in step two 2+ The concentration was 9.0 × 10⁻⁶. -4 mol / L.

[0019] Furthermore, the slurry preparation time in step two is 3 minutes.

[0020] Furthermore, the kerosene in step three has a concentration of 2.5 × 10⁻⁶. -4 mol / L.

[0021] Furthermore, the slurry preparation time in step three is 3 minutes.

[0022] Furthermore, the foaming agent in step four is No. 2 oil with a concentration of 0.8 × 10⁻⁶. -4 mol / L.

[0023] Furthermore, in step four, after adding the foaming agent, the mixture is prepared for 2 minutes.

[0024] Another object of the present invention is to provide a system for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification, comprising:

[0025] The pyrolysis module is used to dry, crush, grind, and sieve the monocrystalline silicon solar panels and glass fragments that have undergone pyrolysis treatment and had their EVA film removed, and then prepare the slurry and adjust the slurry.

[0026] The slurry preparation module is used to add Cu to the obtained slurry. 2+Slurry preparation; after slurry preparation, kerosene is added to the obtained slurry for further preparation; after slurry preparation, a foaming agent is added to the obtained slurry for further preparation;

[0027] The flotation module is used to perform flotation on the obtained slurry using conventional processes to obtain silicon concentrate.

[0028] Another object of the present invention is to provide a computer device including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification.

[0029] Another object of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method for separating elemental silicon and glass in a decommissioned photovoltaic module based on surface modification.

[0030] Another objective of this invention is to provide an information data processing terminal for implementing the system based on surface modification to separate elemental silicon and glass in decommissioned photovoltaic modules.

[0031] Cu in solution 2+ Diffusion to the surface of elemental silicon particles, the silanol groups (-Si-OH) and dangling bonds on the surface of elemental silicon have a strong electron-donating ability, Cu 2+ In aqueous solution, dissociation adsorption occurs, anchoring the active sites on the silicon surface through Cu-Si and O-Si double bonds, forming a continuous and uniform hydrophobic copper film. The hydrophobic copper film on the silicon surface is tightly bound to the hydrocarbon chains of non-polar kerosene through van der Waals forces and hydrogen bonds, significantly enhancing the hydrophobicity of the silicon particles, causing them to float with the flotation foam; the glass particles, due to their hydrophilic surface, remain in the slurry, achieving efficient separation. The glass powder has a stable surface structure and fewer active electron donor sites, allowing Cu... 2+ Adsorption occurs solely through Cu–O coordination, while the surface remains hydrophilic. It is this "selective activation" of silicon and "inactivation" of glass that creates the significant difference in floatability between the two, making efficient separation by flotation possible.

[0032] In the slurry, kerosene molecules collide with all particles. When they encounter a hydrophilic glass surface, the surface is already firmly occupied by water molecules, and the chemical properties are incompatible, preventing the kerosene from adhering stably. Just as water cannot form a stable oil film on clean glass, the kerosene is eventually washed away or dispersed by the water flow. When kerosene encounters elemental silicon, which has relatively weak surface polarity, the kerosene molecules are physically adsorbed onto the silicon surface through strong van der Waals forces. These nonpolar alkane chains further spread and cover the silicon surface under the drive of hydrophobic forces, forming a stable hydrophobic film and transforming its original weak hydrophobicity into strong hydrophobicity. The silicon concentrate to be recovered selectively adheres to the bubbles, forming a mineralized foam layer on the slurry surface. The mineralized foam layer is then scraped off, leaving the glass tailings in the slurry, thus achieving the goal of separating and recovering silicon from retired photovoltaic modules.

[0033] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0034] This invention achieves selective hydrophobic modification of elemental silicon surfaces and completes flotation separation through the synergistic effect of specific ion activation and organic collectors. This solves the technical problem of inefficient separation of silicon and glass in decommissioned photovoltaic modules, demonstrating targeted improvements in both technical methods and implementation mechanisms, resulting in significant separation effects.

[0035] This invention allows for the addition of Cu to flotation slurry systems. 2+ And kerosene, Cu 2+ Activating elemental silicon enhances its hydrophobicity and adsorption capacity for kerosene, while simultaneously increasing its hydrophilicity to glass. Kerosene physically adsorbs onto the surface of elemental silicon, forming a stable hydrophobic film that further strengthens the hydrophobicity of the silicon. Since kerosene has no selectivity for glass powder, the two minerals are effectively separated. Experimental data shows that the silicon recovery rate can reach over 92%, and the silicon grade can also reach over 90%. Compared to traditional recovery methods, such as physical screening and chemical etching, this significantly improves the purity of elemental silicon, providing a high-quality raw material for subsequent resource utilization.

[0036] 1) Good selectivity and high separation efficiency: Utilizing Cu 2+ The selective adsorption of kerosene on the surface of elemental silicon significantly increases the difference in surface hydrophobicity between it and glass powder, achieving efficient separation with a silicon recovery rate of over 95%.

[0037] 2) Low cost and easy industrialization: Kerosene, as a widely available and inexpensive conventional chemical product, greatly reduces reagent costs. The process is simple, and the equipment is conventional flotation equipment, making it easy to achieve large-scale application.

[0038] 3) Environmentally friendly: The entire process is carried out at room temperature, resulting in low energy consumption. Kerosene has low toxicity and is used in small quantities, avoiding the environmental problems caused by the use of strong acids, strong alkalis, or highly toxic collectors.

[0039] 4) High degree of resource utilization: It not only efficiently recovers valuable elemental silicon, but also provides pure raw materials for the subsequent use of glass powder (such as the preparation of building materials), realizing the full resource utilization of photovoltaic modules.

[0040] 5) Energy and resource savings: Effective separation technology reduces energy consumption and raw material waste, contributing to sustainable production.

[0041] 6) The expected benefits and commercial value of the technical solution after the transformation of the present invention are as follows: After the transformation of the technical solution, the recovery efficiency of silicon resources can be greatly improved, production indicators can be improved, and more economic benefits can be brought to enterprises.

[0042] 7) The technical solution of this invention fills a technological gap in the industry both domestically and internationally: currently, Cu is not used in industrial production. 2+ This invention patent proposes a method for separating elemental silicon and glass powder from decommissioned photovoltaic modules using Cu, based on the surface characteristics of elemental silicon and glass powder. 2+ The method separates and captures elemental silicon and glass powder from decommissioned photovoltaic modules from kerosene, thereby improving the resource recycling efficiency of decommissioned photovoltaic modules. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification, provided by an embodiment of the present invention.

[0045] Figure 2 This is a structural block diagram of a silicon-glass separation system provided in an embodiment of the present invention;

[0046] Figure 3 This is a flotation flowchart provided in Embodiment 1 of the present invention;

[0047] Figure 4 This is a flotation flowchart provided in Embodiment 2 of the present invention;

[0048] Figure 5 This invention provides the effect of kerosene concentration on silicon recovery rate and silicon grade in its embodiments.

[0049] Figure 6 The Cu provided in the embodiments of the present invention 2+ The effect of concentration on silicon recovery rate and silicon grade;

[0050] Figure 7 The images provided in this embodiment of the invention are: (a) a physical diagram of flotation separation; and (b) a diagram of the flotation separation mechanism. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] To address the problems existing in the prior art, the present invention provides a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification. The present invention will be described in detail below with reference to the accompanying drawings.

[0053] like Figure 1 As shown in the embodiment of the present invention, a method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification is provided:

[0054] S101, a water-based mineral slurry is prepared by crushing a mixture of monocrystalline silicon solar panels with the organic encapsulation layer removed and glass.

[0055] S102, adjust the pH of the slurry to 8.0;

[0056] S103, add Cu to the slurry at a concentration of 9.0 x 10^-4 moles per liter. 2+ Activate and condition the pulp;

[0057] S104, then kerosene with a concentration of 2.5 x 10^-4 moles per liter was added to the slurry, so that the Cu... 2+ A hydrophobic adsorption layer forms on the activated elemental silicon surface;

[0058] S105, a frother is added to the slurry and flotation is performed, so that the elemental silicon forming the hydrophobic layer enters the foam phase, while the glass remains in the tailings phase, thus obtaining silicon concentrate.

[0059] The slurry provided in this embodiment of the invention consists of 5 grams of solar panel powder, 5 grams of glass powder and 190 ml of deionized water.

[0060] The slurry pH provided in this embodiment of the invention is adjusted to 8.0 using sodium hydroxide.

[0061] Cu provided in the embodiments of the present invention 2+ The mixing time is 3 minutes.

[0062] The kerosene preparation time provided in this embodiment of the invention is 3 minutes.

[0063] The foaming agent provided in this embodiment of the invention is No. 2 oil, the addition amount is 0.8 times 10 to the power of -4 moles per liter, and the slurry preparation time is 2 minutes.

[0064] like Figure 2 As shown, an embodiment of the present invention provides a system for separating elemental silicon from glass, comprising:

[0065] The slurry preparation unit is used to prepare an aqueous slurry from a silicon-glass mixture and adjust the pH to 8.0.

[0066] The metal ion activation unit is used to add Cu to the slurry at a concentration of 9.0 x 10^-4 moles per liter. 2+ To change the surface potential of elemental silicon;

[0067] A nonpolar collector adsorption unit is used to add kerosene at a concentration of 2.5 x 10⁻⁴ moles per liter to the slurry to form a hydrophobic layer on the activated elemental silicon surface.

[0068] The flotation separation unit is used to separate elemental silicon from glass under the action of a foaming agent.

[0069] The metal ion activation unit provided in this embodiment of the invention includes a metering addition module and a stirring and slurry preparation module.

[0070] This invention provides a method for selectively modifying and separating elemental silicon and glass in decommissioned photovoltaic modules. Based on the synergistic effect of the metal ion activation mechanism and the kerosene adsorption mechanism, this method controls the surface modification of Cu... 2+ A concentration of 9.0 x 10⁻⁴ mol / L and a kerosene concentration of 2.5 x 10⁻⁴ mol / L are used to form a hydrophobic interface layer on the surface of elemental silicon and to perform flotation separation.

[0071] The flotation process provided in this embodiment of the invention is carried out after the addition of a frother, wherein the concentration of the frother is 0.8 × 10⁻⁴ moles per liter.

[0072] The method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification provided in this invention includes the following steps:

[0073] (1) After the monocrystalline silicon solar panel and glass fragments that have undergone pyrolysis and EVA film removal are dried, crushed, ground and sieved, a slurry is prepared and adjusted.

[0074] (2) Add Cu to the slurry obtained in (1) 2+ Mix the paste;

[0075] (3) Add kerosene to the slurry obtained in (2) and adjust the slurry;

[0076] (4) Add a foaming agent to the slurry obtained in (3) and adjust the slurry;

[0077] (5) The slurry obtained in (4) is subjected to flotation using conventional processes to obtain silicon concentrate.

[0078] To achieve the above objectives, the method for harvesting elemental silicon and glass powder from decommissioned optical components using kerosene separation provided in this embodiment of the invention includes the following steps:

[0079] 1) After grinding the monocrystalline silicon solar panel and glass fragments separately, add 10g of the mixture of monocrystalline silicon solar panel powder and glass powder and 190mL of water to the flotation cell. Then adjust the slurry for 3 minutes;

[0080] 2) Add Cu to the slurry obtained in step 1). 2+ Mix the slurry for 3 minutes;

[0081] 3) Add kerosene to the slurry obtained in step 2) and adjust the slurry for 3 minutes;

[0082] 4) Add No. 2 oil to the slurry obtained in step 3) and adjust the slurry for 2 minutes;

[0083] 5) The slurry obtained in step 4) is subjected to flotation using conventional processes to obtain silicon concentrate.

[0084] Step 1) refers to grinding the raw ore until the particles with a fineness of -74 μm account for about 90% of the total, or grinding the mixed ore sample to a fineness of -200~325 mesh.

[0085] The concentration of the agent mentioned in step 2) is 9.0 × 10⁻⁶. -4 mol / L.

[0086] The concentration of the agent mentioned in step 3) is 2.5 × 10⁻⁶. -4 mol / L.

[0087] The concentration of the agent mentioned in step 4) is 0.8 × 10⁻⁶. -4 mol / L.

[0088] Adding Cu to the flotation pulp system 2+ And kerosene, Cu 2+A hydrophobic copper film was constructed on a hydrophilic silicon surface through an in-situ redox reaction. This film fundamentally altered the physicochemical properties of the silicon surface, significantly enhancing the adsorption efficiency of the nonpolar collector kerosene. Kerosene physically adsorbed onto the elemental silicon surface, forming a stable hydrophobic film that made elemental silicon more hydrophobic than glass powder. Since kerosene has no selectivity for glass powder, the two minerals were effectively separated. Experimental data showed that the silicon recovery rate could reach over 92%, and the silicon grade could also reach over 90%.

[0089] Example 1

[0090] Monocrystalline silicon solar panels and glass fragments from decommissioned photovoltaic modules that have undergone pyrolysis treatment were crushed using a jaw crusher and a double-roll crusher, and then ground to -74 μm (-200~350 mesh) using a ball mill. The mixed mineral contained approximately 50% solar panel powder (mass fraction) and approximately 50% glass powder. 10g of the above powder was weighed and placed in a 250ml flotation cell, and 190ml of deionized water was added to prepare a 5% concentration slurry. Sodium hydroxide was added to adjust the pH of the slurry to 8, and the slurry was stirred at 1560 rpm for 2 minutes to ensure uniform dispersion. Cu was added. 2+ (Concentration is 9.0 × 10) -4 Adjust the pH of the slurry to 8 using mol / L (500 mol / L) and continue stirring for 3 minutes. After the reaction is complete, add kerosene (2.5 × 10⁻⁶ mol / L). -4 (mol / L), continue stirring for 3 minutes. After the reaction is complete, add foaming agent #2 oil (0.8 × 10⁻⁶ mol / L) to the slurry. -4 The reaction was carried out at a concentration of mol / L for 2 minutes. After the reaction was complete, flotation was started. The aeration device of the flotation machine was turned on, and the aeration rate was controlled at 1.5 L / min. The froth was scraped off for 3 minutes, and the froth was scraped off steadily. The froth product (elemental silicon concentrate) and the product in the tank (glass tailings) were collected, filtered, dried, weighed, and analyzed. Results: Chemical analysis showed that the grade of elemental silicon was 91.5%, and the recovery rate of elemental silicon in the original ore reached 92.8%. The results indicate that Cu 2+ After treatment, the surface potential of silicon decreased, and kerosene adsorption was significantly enhanced.

[0091] Example 2

[0092] Keep all other conditions the same as in Example 1, only cancel Cu. 2+ The addition step. After flotation, the silicon concentrate grade was 74.9%, and the recovery rate was 63.5%. This indicates that kerosene alone has limited adsorption capacity on the silicon surface and is difficult to form a stable hydrophobic layer, verifying the key role of metal ion activation in the synergistic mechanism.

[0093] Example 3

[0094] Keeping all other conditions the same as in Example 1, the kerosene concentration was reduced to 1.0 × 10⁻⁶. -4 mol / L. The experiment found that the silicon recovery rate decreased to 64.3%, indicating that a certain collector concentration must be reached on the basis of activation in order to form a complete hydrophobic film, proving that there is a concentration matching relationship between the two factors.

[0095] Example 4

[0096] Keeping all other conditions the same as in Example 1, Cu 2+ The concentration was increased to 1.1 × 10⁻⁶. -3 mol / L. Experiments showed a significant decrease in silicon recovery and an increase in glass entrainment. Analysis suggests that excess Cu... 2+ Deposits may form on the glass surface, weakening selectivity and demonstrating the innovative technical significance of the optimal concentration range.

[0097] Example 5

[0098] A scale-up experiment was conducted in an industrial continuous flotation cell. The pulp volume was increased to 20 liters, and Cu was added proportionally. 2+ The mixture was combined with kerosene, and the pH was controlled at 8.0. After 4 hours of continuous operation, the average grade of the silicon concentrate remained above 90%, and the recovery rate remained stable above 85%. This demonstrates that the technical solution is feasible and stable for engineering scale-up.

[0099] Example 6

[0100] For Cu 2+ Contact angle tests were performed on activated silicon samples. The contact angle of the untreated silicon surface was 35.37°. After Cu treatment... 2+ After co-treatment with kerosene, the contact angle increased to 77.72°; the contact angle on the glass surface remained below 40°. This data demonstrates the significantly enhanced hydrophobicity of elemental silicon while the glass retains its hydrophilic properties, thus establishing the interfacial physical basis for selective separation.

[0101] Metal ion activation alters the electrochemical state of elemental silicon surfaces, enabling them to undergo directional adsorption with kerosene, with both synergistically constructing a stable hydrophobic layer. This synergistic mechanism exhibits stable separation effects at different concentrations and scales, significantly outperforming single collector systems. The implementation data fully demonstrates the causal relationship between process conditions, parameter ranges, and technical effects, enabling those skilled in the art to directly implement the technology and obtain the expected results, while fully supporting the scope and inventiveness of the technical solution.

[0102] Figure 3 This is a flotation flowchart provided in Embodiment 1 of the present invention;

[0103] Figure 4 This is a flotation flowchart provided in Embodiment 2 of the present invention;

[0104] Evidence related to the technical effects obtained by the embodiments of the present invention.

[0105] like Figure 5 As shown, in Cu 2+ The concentration is 9.0 × 10 -4 The concentration of foaming agent #2 oil is 0.8 × 10 mol / L. -4 The effects of collector kerosene concentration on the efficiency and grade of silicon recovery by flotation were investigated under constant conditions of 2.5 × 10 mol / L, stirring speed, and liquid-solid ratio. Experimental results showed that a kerosene concentration of 2.5 × 10 mol / L was optimal. -4 The silicon grade and recovery rate are optimal at a concentration of mol / L.

[0106] like Figure 6 As shown, at a kerosene concentration of 2.5 × 10 -4 The concentration of foaming agent #2 oil is 0.8 × 10 mol / L. -4 The activator Cu was investigated under constant conditions such as mol / L, stirring speed, and liquid-solid ratio. 2+ The effect of concentration on the efficiency and grade of silicon recovery by flotation. Experimental results show that in Cu... 2+ The concentration is 9.0 × 10 -4 The silicon grade and recovery rate are optimal at a concentration of mol / L.

[0107] Figure 7 (a) Actual image of flotation separation; (b) Schematic diagram of flotation separation mechanism.

[0108] As shown in Table 1, flotation experiments can yield results for Cu. 2+ The concentration is 9.0 × 10 -4 At a concentration of Cu, the silicon recovery rate can reach 92.8%, and the silicon grade in the concentrate reaches 91.5%; the glass recovery rate can reach 91.3%, and the glass grade in the tailings reaches 89.4%. Experimental data show that by using Cu... 2+ Activation and kerosene harvesting can effectively separate silicon and glass minerals.

[0109] Table 1 Flotation data results

[0110]

[0111] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for separating elemental silicon and glass in decommissioned photovoltaic modules based on surface modification, characterized in that, Includes the following steps: Step 1: The mixture of silicon wafers and glass after the organic encapsulation layer has been removed is pulverized and prepared into an aqueous mineral slurry; Step 2: Adjust the pH of the pulp to 8.0; Step 3: Add Cu2+ to the slurry at a concentration of 9.0 x 10^-4 moles per liter for activation and slurry conditioning; Step 4: Subsequently, kerosene with a concentration of 2.5 x 10^-4 moles per liter is added to the slurry, so that the Cu... 2+ A hydrophobic adsorption layer forms on the activated elemental silicon surface; Step 5: Add a frother to the slurry and perform flotation, so that the elemental silicon forming the hydrophobic layer enters the foam phase, while the glass remains in the tailings phase, thus obtaining silicon concentrate.

2. The method as described in claim 1, characterized in that, The slurry consists of 5 grams of solar panel powder, 5 grams of glass powder, and 190 ml of deionized water.

3. The method as described in claim 1, characterized in that, The pH of the slurry was adjusted to 8.0 using sodium hydroxide.

4. The method as described in claim 1, characterized in that, The Cu 2+ The mixing time is 3 minutes.

5. The method as described in claim 1, characterized in that, The kerosene preparation time is 3 minutes.

6. The method as described in claim 1, characterized in that, The foaming agent is No. 2 oil, and the addition amount is 0.8 × 10⁻⁴ moles per liter, with a slurry preparation time of 2 minutes.

7. A system for separating elemental silicon from glass for implementing the method of claim 1, characterized in that, include: The slurry preparation unit is used to prepare an aqueous slurry from a silicon-glass mixture and adjust the pH to 8.

0. The metal ion activation unit is used to add Cu to the slurry at a concentration of 9.0 x 10^-4 moles per liter. 2+ To change the surface potential of elemental silicon; A nonpolar collector adsorption unit is used to add kerosene at a concentration of 2.5 x 10⁻⁴ moles per liter to the slurry to form a hydrophobic layer on the activated elemental silicon surface. The flotation separation unit is used to separate elemental silicon from glass under the action of a foaming agent.

8. The system as described in claim 7, characterized in that, The metal ion activation unit includes a metering addition module and a stirring and slurry preparation module.

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