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CN-121988589-A - Photovoltaic module thermal decomposition recovery method based on Joule heating

CN121988589ACN 121988589 ACN121988589 ACN 121988589ACN-121988589-A

Abstract

The invention relates to the technical field of recycling of photovoltaic waste resources and discloses a thermal decomposition recycling method of a photovoltaic module based on Joule heating, which comprises the following steps of mechanically disassembling the waste photovoltaic module, separating an aluminum frame, copper wires, plastics and glass, and crushing the residual photovoltaic cell core material into powder with the particle size smaller than 200 mu m to obtain photovoltaic waste powder; and (3) mixing the materials, namely uniformly mixing the photovoltaic waste powder and the conductive additive according to the mass ratio of 1:1-3:1, adding the chlorinating agent, and stirring until the mixture is uniformly dispersed to form a mixed material, wherein the conductive additive is conductive carbon black with the specific surface area of more than or equal to 1500m 2 /g. By adopting a treatment mode of coupling Joule heating and electric heating chlorination, ultra-rapid localized heating of materials is realized by virtue of Joule heating, and directional separation and recovery of metals such as silver, copper, aluminum and the like in the photovoltaic module can be efficiently realized by matching with selective chlorination reaction of a chlorinating agent, and meanwhile, effective enrichment of silicon resources is realized.

Inventors

  • JIANG ZEXU

Assignees

  • 南京师范大学

Dates

Publication Date
20260508
Application Date
20260317

Claims (9)

  1. 1. The thermal decomposition recovery method of the photovoltaic module based on Joule heating is characterized by comprising the following steps of: (1) Pre-treating, namely mechanically disassembling the waste photovoltaic module, separating an aluminum frame, copper wires, plastics and glass, and crushing the residual photovoltaic cell core material into powder with the particle size smaller than 200 mu m to obtain photovoltaic waste powder; (2) Mixing the photovoltaic waste powder and a conductive additive uniformly according to the mass ratio of 1:1-3:1, and adding a chlorinating agent, stirring until the mixture is uniformly dispersed to form a mixed material, wherein the conductive additive is conductive carbon black with the specific surface area of more than or equal to 1500m 2 /g, and the chlorinating agent is at least one of NaCl, KCl, caCl 2 and HCl; (3) The method comprises the steps of joule heating-electrothermal chlorination coupling treatment, namely loading a mixed material into a borosilicate glass reaction tube with graphite felts at two ends, connecting graphite electrodes at the outer sides of the graphite felts, applying 90-150V voltage through a joule heating device to perform flash evaporation heating, wherein the flash evaporation time is 1-5 times, and the flash evaporation time is 0.5s each time, so that the mixed material is heated to 2000-3400K within 0.5s, the electrothermal chlorination reaction of metal oxide and a chlorinating agent is realized, and volatile metal chloride is generated; (4) And separating and recovering, namely capturing volatile metal chloride by a condensation and collection device, obtaining silver, copper and aluminum simple substances or compounds thereof through subsequent treatment, and collecting reaction residues to recover silicon resources.
  2. 2. The method for recycling thermal decomposition of a photovoltaic module based on joule heating according to claim 1, wherein the optimal mass ratio of the photovoltaic waste powder to the conductive carbon black in the step (2) is 2:1, and the conductivity of the mixed material is more than or equal to 10S/m at the ratio, so that rapid localized heating can be realized.
  3. 3. The method for recycling thermal decomposition of photovoltaic module based on joule heating according to claim 1, wherein the chlorinating agent is added in an amount of 5% -20% by mass of the photovoltaic waste powder in step (2), and when HCl is used as the chlorinating agent, it is added in the form of an aqueous solution with a mass fraction of 10% -37%.
  4. 4. The method for recovering heat of a photovoltaic module based on joule heating according to claim 1, wherein the joule heating device in the step (3) comprises a capacitor discharge system, a charge-discharge control system, a data acquisition system and a reaction cavity, the reaction cavity is a borosilicate glass tube with an inner diameter of 8mm and a length of 60mm, and an inert atmosphere is maintained for protection during operation.
  5. 5. The thermal decomposition recovery method of a photovoltaic module based on joule heating according to claim 1, wherein the optimal process parameters of flash evaporation heating in the step (3) are voltage 130V and flash evaporation times 3 times, and under the condition, the recovery rate of silver is more than or equal to 94.5%, and the recovery rates of copper and aluminum are more than or equal to 90%.
  6. 6. The method for recovering the thermal decomposition of the photovoltaic module based on the Joule heating according to claim 1, wherein the electrothermal chlorination reaction in the step (3) follows the principle of thermodynamic selectivity, and the reaction temperature is controlled to enable the metal oxide to react with the chlorinating agent, namely MO x +xCl 2 →MCl 2x +(x/2)O 2 , wherein M is any one of Ag, cu and Al, and the Gibbs free energy delta G <0 of the reaction ensures the spontaneous reaction.
  7. 7. The method for recovering the thermal decomposition of the photovoltaic module based on the Joule heating according to claim 1, further comprising a machine learning optimization step, wherein voltage, the mass ratio of the photovoltaic waste to the conductive carbon black, the type of the chlorinating agent and the flash evaporation times are taken as input characteristics, metal recovery rate is taken as target output, XGBoost regression models are built, the determination coefficient R 2 of the models is more than or equal to 0.99, root mean square error RMSE is less than or equal to 0.00004, and optimal technological parameter combinations are predicted through the models.
  8. 8. The method for recovering heat of a photovoltaic module based on joule heating according to claim 1, wherein the condensation collection device in the step (4) adopts a gradient condensation design, and realizes graded recovery according to the boiling point difference of different metal chlorides, thereby improving the purity of the product.
  9. 9. The thermal decomposition recovery method of a photovoltaic module based on joule heating according to claim 1, which is suitable for metal recovery of monocrystalline silicon, polycrystalline silicon and film-type waste photovoltaic modules, wherein the purity of silver in the recovered product is more than or equal to 99.0%, the purity of copper is more than or equal to 98.5%, the purity of aluminum is more than or equal to 98.0%, and the silicon content in the silicon residue is more than or equal to 90%, and can be directly used for secondary processing.

Description

Photovoltaic module thermal decomposition recovery method based on Joule heating Technical Field The invention relates to the technical field of photovoltaic waste resource recycling, in particular to a thermal decomposition recycling method of a photovoltaic module based on joule heating. Background Along with the rapid development of the global new energy industry, the realization of the installed scale is continuously and greatly increased as an important form of clean energy, and a large number of photovoltaic modules gradually enter a scrapping period, so that the generation amount of photovoltaic waste material is in a year-by-year rising trend. The photovoltaic module is of a multi-material composite structure, and besides glass, polymer and other base materials, the photovoltaic module also contains silver, copper, aluminum and other high-value metals and silicon and other key semiconductor materials, so that valuable resources have extremely high recycling value, recycling of photovoltaic waste is realized, supply pressure of mineral resources can be relieved, and the photovoltaic industry can be promoted to form a closed-loop circular economy system, and therefore the efficient recycling technology of the photovoltaic waste becomes a research focus in the field of new energy and resource recycling. At present, the recovery treatment method for the photovoltaic module is mainly divided into three major types of a mechanical recovery method, a heat recovery method and a chemical recovery method, and all the methods form a corresponding technical system in practical application. The mechanical recovery method is characterized in that the recovery of easily-separated components such as glass and aluminum frames in the photovoltaic module is realized through physical means such as crushing, grinding, sorting and the like, the operation flow of the method is simple, the early investment is low, the method is a common means for preprocessing photovoltaic waste, the heat recovery method mainly utilizes modes such as high-temperature incineration, pyrolysis and the like to remove organic substrates in the photovoltaic module, then metal extraction is carried out on the residual solid-phase products, and the separation of partial metals and nonmetal can be realized, and the chemical recovery method is one of the main methods for realizing the high-purity recovery of metals at present through leaching, extraction, reduction and the like by means of chemical reagents such as acid, alkali, complexing agents and the like. In addition, some researches try to combine a mechanical method with a thermal method and a chemical method so as to improve the recovery efficiency, and various prior arts are applied to the field of photovoltaic waste recovery to a certain extent. However, in the practical industrial application of the existing photovoltaic module recycling technology, a plurality of technical defects which are difficult to overcome still exist, so that the recycling effect of the photovoltaic waste is poor, and the requirement of industrial development cannot be met. Firstly, the mechanical recovery method can only recover a few easily-separated components in the photovoltaic module, is difficult to realize effective dissociation and extraction of noble metals such as silver, copper and the like embedded in a battery core material, has low recovery types and recovery rates of valuable resources, and a large amount of high-value metals are discarded along with residues, so that the resources are seriously wasted, and the heat recovery method can realize removal of an organic substrate, but the traditional high-temperature heating mode is an integral heating mode, has large heat loss and high energy consumption, and the heating process is easy to cause oxidation or agglomeration of metals, so that the subsequent separation difficulty is increased, toxic and harmful gases are also easy to generate in the incineration process, secondary environmental pollution is caused, and the environmental protection treatment cost is higher. In addition, the chemical recovery method can realize the high-purity recovery of metals, but needs a large amount of corrosive chemical reagents such as strong acid, strong alkali and the like, has large reagent consumption and high recovery cost, generates a large amount of waste acid, waste alkali and waste residues in the reaction process, is extremely easy to cause serious water and soil pollution if being improperly treated, has high environmental protection pressure, and has long reaction period of chemical leaching and separation, complicated working procedures, difficult realization of continuous and efficient production and limited industrialized application. In addition, the existing recovery technologies are mostly developed aiming at the recovery of single metal or few components, the collaborative recovery design of multiple valuable resources such as silver, copper, alumi