Method for preparing perovskite precursor lead iodide from secondary lead electrolysis ingot casting slag

Abstract

The invention relates to a method for preparing a perovskite precursor lead iodide from secondary lead electrolysis ingot casting slag, which comprises the following steps: a grinding process: grinding the secondary lead electrolysis ingot casting slag into lead powder through a grinding mechanism, and separating the lead powder into a dissolving mechanism through a separating mechanism; a dissolving process: controlling the temperature in a dissolving mechanism to be 40-60 DEG C, adding an acetic acid solution, controlling the temperature to be 260-300 DEG C, and adding nitric acid and deionized water; a generation process: after carrying out suction filtration to obtain a lead nitrate solution, dropwise adding the lead nitrate solution into the sodium iodide solution in the generation mechanism, keeping the pH value of the mixed solution at 1-3, and controlling the temperature at 50-60 DEG C to react for 2-3 hours; and a drying process: washing the lead iodide mixed solution with deionized water, carrying out suction filtration, drying to obtain a lead iodide crude product, recrystallizing the lead iodide crude product, and drying to obtain the high-purity lead iodide. The invention solves the problems of resource waste, influence on production efficiency and environmental pollution caused by the fact that the existing secondary lead electrolysis ingot casting slag cannot be reasonably recycled.

Description

Technical Field

[0001] This invention relates to the field of lead iodide preparation technology, and in particular to a method for preparing perovskite precursor lead iodide from recycled lead electrolytic casting slag. Background Technology Modern research on photovoltaic devices began with crystalline silicon solar cells. Compared with traditional solar cells, current perovskite solar cells have the characteristics of low manufacturing cost, light weight of photovoltaic modules, and flexible production, thus showing rapid development in the optoelectronic field. Lead iodide, as a key raw material for preparing the perovskite light-absorbing layer, has a crucial impact on the efficiency and stability of perovskite photovoltaic modules due to its purity, crystallinity, and microstructure. Recycled lead raw materials, such as lead paste and lead alloys from waste lead-acid batteries, are initially smelted using pyrometallurgy to obtain crude lead containing about 95%-98% lead. When the refined high-purity electrolytic lead liquid is cast into commercial lead ingots, a layer of slag mainly composed of lead oxide will form on the surface of the lead liquid due to high-temperature oxidation and slag protection measures. This is the recycled lead electrolytic ingot slag.

[0002] Patent document CN105803205A discloses a high-efficiency and energy-saving recycled lead smelting process. The process steps are as follows: waste lead-acid batteries are automatically disassembled, and the resulting carbonated lead paste and flux are fed into an oxygen-enriched smelting furnace for smelting, producing crude lead, lead slag, and low-concentration SO2 flue gas. The SO2 flue gas is treated by waste heat recovery and dust collection devices before being sent to a desulfurization system for desulfurization to meet emission standards. The lead slag is sold as vitrified general waste to cement plants as raw material. The crude lead is refined through electrolytic refining to obtain refined lead and anode mud, which are then sold externally. The system implementing this process includes an oxygen-enriched side-blown smelting furnace, feeding equipment, slag water quenching equipment, cooling equipment, dust collection equipment, and desulfurization equipment. This invention, through process design and system improvement, achieves clean and efficient recovery of Pb, Ag, Cu, Sb, and Sn elements.

[0003] However, in the actual process of recycled lead smelting, the inventors found that the existing recycled lead electrolytic casting slag is usually regarded as industrial hazardous solid waste and cannot be reasonably recycled and utilized. Recycled lead enterprises usually generate huge amounts every day, resulting in high hazardous waste disposal costs, resource waste, impact on production efficiency, and resource waste. At the same time, because it contains a large amount of soluble lead compounds, if it is piled up at will, it will seriously pollute the environment such as soil and water sources. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by incorporating grinding, dissolving, generating, and drying processes to transform recycled lead electrolytic ingot slag, which would otherwise be treated as waste, into functional chemicals with high economic value. This provides a low-cost and sustainable raw material supply route for the production of lead iodide materials, a perovskite precursor, reducing dependence on primary lead ore and providing a new and stable source of raw materials for the perovskite industry, aligning with the circular economy principle. This solves the problems of inefficient recycling of recycled lead electrolytic ingot slag, which leads to resource waste, reduced production efficiency, and environmental pollution.

[0005] To address the above technical problems, the following technical solution is adopted: A method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag, comprising the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 10-40 mesh by a grinding mechanism. Then, the lead powder in each mesh range is separated into the reaction chambers of the dissolving mechanism by a separation mechanism. Step 2: Dissolution process. The temperature inside the dissolution mechanism is controlled at 40-60℃. After slowly adding acetic acid solution with a mass percentage of 30-60% into the reaction chamber, the temperature inside the dissolution mechanism is controlled at 260-300℃. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed by the reaction in the dissolving mechanism to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism. During the dropwise addition process, the pH of the mixed solution is maintained at 1-3, and the temperature in the generation mechanism is controlled at 50-60℃ for 2-3 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then transported to the drying unit and dried at 60-80°C for 4-6 hours to obtain crude lead iodide. The crude lead iodide is then added to the recrystallization unit for recrystallization. After recrystallization, the product is washed and filtered with an alcohol solution. The resulting moist crystals are then transported to the drying unit and dried at 60-80°C for 4-6 hours to obtain high-purity lead iodide.

[0006] Preferably, the grinding mechanism includes a grinding chamber with an inclined bottom, a feed inlet that opens and closes on the side wall of the grinding chamber, a plurality of discharge outlets that open and close on the side wall of the grinding chamber, a grinding assembly that is rotatably disposed at the bottom of the grinding chamber, a conical protrusion disposed on the inner wall of the grinding chamber for guiding lead powder to the grinding assembly, and a fluidizing assembly disposed in the grinding chamber for blowing lead powder to form a fluidized state.

[0007] Preferably, the grinding assembly includes a shaft rotatably disposed in the grinding chamber, a grinding roller disposed on the shaft and forming a grinding zone with the inclined structure, a plurality of first grinding blocks spaced apart in the vertical direction on the inclined structure, and a plurality of second grinding blocks spaced apart in the vertical direction on the grinding roller and respectively located between a plurality of adjacent first grinding blocks.

[0008] Preferably, the fluidization assembly includes an air inlet channel formed inside the shaft, a plurality of first jet ports with one end connected to the air inlet channel and the other end extending through to the space between the two second grinding blocks, a plurality of second jet ports with one end connected to the air inlet channel and the other end extending through to the outer wall of the shaft at the position corresponding to the conical protrusion, an air outlet channel that opens and closes at the upper end of the grinding chamber, and a dust collector disposed in the air outlet channel.

[0009] Preferably, the separation mechanism includes a plurality of conical shrouds spaced vertically above the second jet nozzle within the grinding chamber, with their inner diameters gradually decreasing from top to bottom; a separation chamber formed between two adjacent conical shrouds and respectively connected to the corresponding discharge port; a discharge assembly disposed within the grinding chamber; a first sieving hole formed on the upper end face of the conical shroud; and a second sieving hole formed on the side wall of the conical shroud. The mesh size of the first sieving hole is smaller than that of the second sieving hole. The mesh size of the first sieving hole on the plurality of conical shrouds gradually decreases from top to bottom, thereby enabling each separation chamber to separate lead powder within a certain mesh size range.

[0010] Preferably, the discharge assembly includes a plurality of third jet ports, one end of which is connected to the air inlet channel and the other end of which respectively penetrates to the bottom of the plurality of conical hoods; a control valve disposed between the second jet port and the third jet port and used to control the opening and closing of the air inlet channel; a plurality of discharge plates disposed on the shaft and used to push the lead powder in each of the separation chambers to the discharge port; a plurality of storage bins respectively connected to the plurality of discharge ports; and a spray pipe disposed on each of the discharge bins and connected to each of the reaction chambers.

[0011] Preferably, both the dissolving mechanism and the generating mechanism include a reaction chamber, a plurality of reaction chambers formed within the reaction chamber, an adding component disposed on the reaction chamber, a temperature control component disposed between the plurality of reaction chambers, and a plurality of filtration components disposed on one side of the reaction chamber.

[0012] Preferably, the drying mechanism includes a drying chamber, a plurality of drying chambers formed within the drying chamber and each equipped with the temperature control component, a conveying component disposed within the drying chamber, and a plurality of partitions spaced apart on the conveying component.

[0013] Preferably, the temperature control assembly includes a heater disposed outside the reaction chamber for heating and conveying the heat transfer fluid, a first heating pipe connected to the heater and arranged in an S-shape outside the bottom of a plurality of reaction chambers in the dissolution mechanism, a second heating pipe connected to the first heating pipe and arranged in an S-shape on the sidewalls of a plurality of drying chambers, a blower disposed on the sidewalls of the drying chamber for blowing hot air outside the second heating pipe into the drying chamber, and a third heating pipe connected at one end to the second heating pipe and arranged in an S-shape outside the bottom of a plurality of reaction chambers in the generation mechanism and then connected to the heater.

[0014] Preferably, the filtration assembly includes multiple filtration tubes that are openable and closable on the reaction chamber and respectively connected to multiple reaction chambers, filters disposed on the filtration tubes, multiple chamber doors that are rotatably disposed on the reaction chamber and respectively used to control the opening and closing of multiple reaction chambers, and a pusher plate that is movable and rotatably disposed in the reaction chamber.

[0015] The beneficial effects of this invention are: (1) In this invention, lead iodide is prepared from recycled lead electrolytic casting slag by setting up grinding, dissolving, generating and drying processes. The recycled lead electrolytic casting slag, which originally needed to be disposed of as waste, is transformed into a functional chemical with high economic value, realizing the transformation of waste into treasure. It provides a low-cost and sustainable raw material supply route for the production of perovskite precursor lead iodide materials. Compared with the direct use of pure metallic lead, it significantly reduces the raw material procurement cost, reduces the dependence on primary lead ore, and provides a new and stable source of raw material supply for the perovskite industry, which is in line with the circular economy. (2) In this invention, the recycled lead electrolytic casting slag is ground into lead powder by setting a grinding process and then graded and separated for graded reaction treatment. This ensures the completeness, uniformity and efficiency of the reaction in the subsequent dissolution and generation processes, avoids the problem of incomplete reaction caused by uneven particle size, and helps the lead iodide generation reaction to proceed smoothly by controlling the reaction temperature, pH value and reaction time in the subsequent dissolution and generation processes, thereby improving the purity and yield of the product. At the same time, the soluble inorganic salt impurities are effectively removed by washing and filtration in the drying process, and the trace impurities wrapped or adsorbed during the synthesis process can be greatly removed by recrystallization, further improving the purity of lead iodide to meet the requirements of high-tech fields such as perovskite solar cells. (3) In this invention, by setting an air intake channel and cooperating with the first jet nozzle, the airflow is directly sprayed onto the core area where the grinding action occurs between multiple first grinding blocks and multiple second grinding blocks, so as to fluidize and transport the lead powder in real time, and directly cool the grinding area. The fluidized lead powder is further fluidized by the second jet nozzle, which improves the fluidization effect of the lead powder, ensures smooth material flow and no residue, and cooperates with the mesh size difference between the first screening hole and the second screening hole on the conical cover, so that only sufficiently fine lead powder can pass through the first screening hole and the second screening hole to flow upward. The lead powder of the current mesh size is guided to the corresponding first screening hole through the lower surface of the conical cover and enters the corresponding separation chamber. After that, it is separated by being guided to the outside through the upper surface of the conical cover. At the same time, the third jet nozzle is used in conjunction with the control valve to realize the fluidization and screening of lead powder in each separation chamber, thereby improving the separation accuracy. In summary, this method has the advantages of rationally recycling and utilizing recycled lead electrolytic casting slag, avoiding resource waste, improving production efficiency, and reducing environmental pollution. It is especially suitable for the field of lead iodide preparation technology. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments 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.

[0017] Figure 1 The present invention provides a process flow diagram for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag.

[0018] Figure 2 This is a perspective view of an apparatus for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag, provided by the present invention.

[0019] Figure 3 This is a perspective view of the grinding mechanism and the separation mechanism provided by the present invention.

[0020] Figure 4 A three-dimensional sectional view of the grinding mechanism and the separation mechanism provided by the present invention.

[0021] Figure 5 Provided by the present invention Figure 4 A magnified view of a portion of point A in the middle.

[0022] Figure 6 Provided by the present invention Figure 4 A magnified view of a section at point B.

[0023] Figure 7 A cross-sectional view of the grinding mechanism provided by the present invention.

[0024] Figure 8 Provided by the present invention Figure 7 A magnified view of a section at point C.

[0025] Figure 9 Provided by the present invention Figure 7 A magnified view of a section at point D.

[0026] Figure 10 Provided by the present invention Figure 7 A magnified view of a section at point E in the middle.

[0027] Figure 11 Provided by the present invention Figure 7 Flow path diagram of lead powder.

[0028] Figure 12 This is a perspective view of the dissolving mechanism and the generating mechanism provided by the present invention.

[0029] Figure 13 A three-dimensional sectional view of the dissolving mechanism provided by the present invention.

[0030] Figure 14 A cross-sectional view of the dissolving mechanism provided by the present invention.

[0031] Figure 15 A three-dimensional sectional view of the drying mechanism provided by the present invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0033] Example 1 like Figures 1-2 as well as Figures 12-13 As shown, a method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag includes the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 10-40 mesh by the grinding mechanism 1. Then, the lead powder in each mesh range is separated into the reaction chambers 32 of the dissolving mechanism 3 by the separation mechanism 2. Step 2: Dissolution process. The temperature inside the dissolution mechanism 3 is controlled at 40-60℃. After slowly adding acetic acid solution with a mass percentage of 30-60% into the reaction chamber 32, the temperature inside the dissolution mechanism 3 is controlled at 260-300℃. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed in the dissolving mechanism 3 to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism 4. During the dropwise addition, the pH of the mixed solution is maintained at 1-3, and the temperature in the generation mechanism 4 is controlled at 50-60℃ for 2-3 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then transferred to drying unit 5 and dried at 60-80℃ for 4-6 hours to obtain crude lead iodide. The crude lead iodide is then added to recrystallization unit 6 for recrystallization. The resulting moist crystals are then transferred to drying unit 5 and dried at 60-80℃ for 4-6 hours to obtain high-purity lead iodide.

[0034] In this embodiment, a grinding process is incorporated to grind the recycled lead electrolytic ingot slag into lead powder. The recycled lead electrolytic ingot slag has a complex composition containing metallic lead, oxides, and silicates, resulting in significant differences in hardness and uneven particle size after grinding. Therefore, a graded separation process is required before further graded reaction treatment. This ensures the completeness, uniformity, and efficiency of the reactions in subsequent dissolution and formation processes, avoiding incomplete reactions caused by uneven particle size. Furthermore, controlling the reaction temperature, pH value, and reaction time during the subsequent dissolution and formation processes facilitates the smooth formation of lead iodide, improving product purity and yield. Additionally, the drying process, through washing and filtration, effectively removes lead iodide. In addition to soluble inorganic salt impurities, recrystallization can greatly remove trace impurities encapsulated or adsorbed during the synthesis process, further improving the purity of lead iodide to meet the requirements of high-tech fields such as perovskite solar cells. The entire preparation process transforms recycled lead electrolytic casting slag, which would otherwise be disposed of as waste, into functional chemicals with high economic value, turning waste into treasure. This provides a low-cost and sustainable raw material supply route for the production of perovskite precursor lead iodide materials. Compared with the direct use of pure metallic lead, it significantly reduces the cost of raw material procurement, reduces dependence on primary lead ore, and provides a new and stable source of raw materials for the perovskite industry, which is in line with the circular economy.

[0035] It should be noted that the recrystallization process of recrystallization unit 6 involves adding crude lead iodide to glacial acetic acid, then adding a dispersant (such as polyvinyl alcohol or polycarboxylic acid) and recrystallizing for 24-36 hours, followed by filtration and washing with alcohol (such as anhydrous ethanol or anhydrous methanol).

[0036] Example 2 like Figures 1-2 as well as Figures 12-13 As shown, a method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag includes the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 10-20 mesh by the grinding mechanism 1, and the lead powder is separated into the reaction chamber 32 of the dissolving mechanism 3 by the separation mechanism 2. Step 2: Dissolution process. The temperature inside the dissolution mechanism 3 is controlled at 40℃. After slowly adding acetic acid solution with a mass percentage of 30% into the reaction chamber 32, the temperature inside the dissolution mechanism 3 is controlled at 260℃. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed in the dissolving mechanism 3 to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism 4. During the dropwise addition process, the pH of the mixed solution is maintained at 1-2, and the temperature in the generation mechanism 4 is controlled at 50℃ for 2 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then transferred to drying unit 5 and dried at 60°C for 4 hours to obtain crude lead iodide. The crude lead iodide is then added to recrystallization unit 6 for recrystallization. The resulting moist crystals are then transferred to drying unit 5 and dried at 60°C for 4 hours to obtain high-purity lead iodide.

[0037] Example 3 As shown in the figure Figures 1-2 as well as Figures 12-13 As shown, a method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag includes the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 20-30 mesh by the grinding mechanism 1, and then separated into the reaction chamber 32 of the dissolving mechanism 3 by the separation mechanism 2. Step 2: Dissolution process. The temperature inside the dissolution mechanism 3 is controlled at 50°C. After slowly adding acetic acid solution with a mass percentage of 45% into the reaction chamber 32, the temperature inside the dissolution mechanism 3 is controlled at 280°C. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed in the dissolving mechanism 3 to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism 4. During the dropwise addition process, the pH of the mixed solution is maintained at 2-3, and the temperature in the generation mechanism 4 is controlled at 55℃ for 3 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then conveyed to drying unit 5 and dried at 70°C for 5 hours to obtain crude lead iodide. The crude lead iodide is then added to recrystallization unit 6 for recrystallization. The resulting moist crystals are then conveyed to drying unit 5 and dried at 70°C for 5 hours to obtain high-purity lead iodide.

[0038] Example 4 like Figures 1-2 as well as Figures 12-13 As shown, a method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag includes the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 30-40 mesh by the grinding mechanism 1, and then separated into the reaction chamber 32 of the dissolving mechanism 3 by the separation mechanism 2. Step 2: Dissolution process. The temperature inside the dissolution mechanism 3 is controlled at 60°C. After slowly adding 60% acetic acid solution by mass into the reaction chamber 32, the temperature inside the dissolution mechanism 3 is controlled at 300°C. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed in the dissolving mechanism 3 to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism 4. During the dropwise addition process, the pH of the mixed solution is maintained at 3, and the temperature in the generation mechanism 4 is controlled at 50°C for 4 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then conveyed to drying unit 5 and dried at 80°C for 6 hours to obtain crude lead iodide. The crude lead iodide is then added to recrystallization unit 6 for recrystallization. The resulting moist crystals are then conveyed to drying unit 5 and dried at 80°C for 6 hours to obtain high-purity lead iodide.

[0039] Example 5 like Figure 2 As shown, an apparatus for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag, is based on a method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag in Example 1, comprising: The apparatus comprises: a grinding mechanism 1 for grinding recycled lead electrolytic casting slag into lead powder; a separation mechanism 2 for separating lead powder of various mesh sizes within the grinding mechanism 1; a dissolving mechanism 3 for dissolving the graded lead powder into a lead-containing solution within the graded reaction outside the grinding mechanism 1; a generating mechanism 4 for reacting the lead-containing solution to generate lead iodide within the dissolving mechanism 3; a drying mechanism 5 for drying moist lead iodide into crude lead iodide within the generating mechanism 4; and a recrystallization mechanism 6 for recrystallizing the crude lead iodide into high-purity lead iodide within the drying mechanism 5.

[0040] In this embodiment, by setting up a grinding mechanism 1 in conjunction with a separation mechanism 2, a dissolving mechanism 3, a generating mechanism 4, and a recrystallization mechanism 6, an integrated, continuous, and automated special production equipment for preparing high-purity lead iodide from recycled lead electrolytic casting slag is provided. This transforms the preparation process into industrial equipment that can operate stably, efficiently, and safely, thereby realizing large-scale production of waste slag resource utilization, reducing human operation errors and risks, ensuring that each batch of lead iodide products has stable and high purity, and protecting the safety and health of workers.

[0041] Furthermore, such as Figures 2-3 As shown, the grinding mechanism 1 includes a grinding chamber 11 with an inclined bottom structure 17, a feed inlet 12 that opens and closes on the side wall of the grinding chamber 11, a plurality of discharge outlets 13 that open and close on the side wall of the grinding chamber 11, a grinding assembly 14 that is rotatably disposed at the bottom of the grinding chamber 11, a conical protrusion 15 disposed on the inner wall of the grinding chamber 11 for guiding lead powder to the grinding assembly 14, and a fluidizing assembly 16 disposed in the grinding chamber 11 for blowing lead powder to form a fluidized state.

[0042] In this embodiment, by setting a grinding chamber 11 with an inclined bottom structure 17 and a conical protrusion 15, the recycled lead electrolytic casting slag introduced by the feed inlet 12 is automatically concentrated at the grinding component 14 for grinding by gravity, which improves the grinding effect. In addition, the airflow of the fluidization component 16 can promptly blow the lead powder that has reached the target particle size, avoiding repeated over-grinding of the lead powder in the grinding zone. This not only saves energy consumption, but also prevents the lead powder from softening, adhering or oxidizing due to excessive local temperature caused by grinding heat, which would affect subsequent production. Furthermore, the lead powder is initially classified and transported by the airflow under the action of gravity, which creates key conditions for subsequent separation and discharge.

[0043] It should be noted that the inlet 12 and outlet 13 themselves and their installation methods are existing technologies, and will not be described in detail here.

[0044] Furthermore, such as Figure 5As shown, the grinding assembly 14 includes a shaft 141 rotatably disposed in the grinding chamber 11, a grinding roller 142 disposed on the shaft 141 and forming a grinding zone with the inclined structure 17, a plurality of first grinding blocks 143 spaced apart in the vertical direction on the inclined structure 17, and a plurality of second grinding blocks 144 spaced apart in the vertical direction on the grinding roller 142 and respectively located between a plurality of adjacent first grinding blocks 143.

[0045] In this embodiment, by setting the shaft 141 to drive the grinding roller 142 to rotate, multiple first grinding blocks 143 and multiple second grinding blocks 144 form multiple grinding gaps, which crush the material after squeezing, shearing and friction, realizing continuous multi-stage crushing, so that the material is gradually refined in a continuous and controllable shearing process, with high grinding efficiency and better energy consumption utilization.

[0046] It should be noted that the distance between the grinding roller 142 and the inclined structure 17 gradually decreases from top to bottom, realizing step-by-step grinding, continuous multi-stage crushing, high grinding completeness, and improved grinding effect. Furthermore, multiple first grinding blocks 143 and second grinding blocks 144 are provided at intervals along the circumference of the shaft 141, which further improves the grinding effect.

[0047] Furthermore, such as Figures 5-11 As shown, the fluidization assembly 16 includes an air inlet channel 161 formed inside the shaft 141, a plurality of first jet ports 162 with one end connected to the air inlet channel 161 and the other end extending between two second grinding blocks 144, a plurality of second jet ports 163 with one end connected to the air inlet channel 161 and the other end extending to the corresponding conical protrusion 15 on the outer wall of the shaft 141, an air outlet channel 164 that is openable and closable at the upper end of the grinding chamber 11, and a dust collector 165 disposed in the air outlet channel 164.

[0048] In this embodiment, by setting an air inlet channel 161 in conjunction with a first jet nozzle 162, the airflow is directly sprayed onto the core area where the grinding action occurs, which immediately fluidizes and transports the lead powder and directly cools the grinding area. The fluidized lead powder, in conjunction with a second jet nozzle 163, further assists in fluidization, improves the fluidization effect of the lead powder, and ensures smooth material flow without residue. At the same time, the air outlet channel 164 and the dust collector 165 immediately separate the gas and lead powder, realizing internal circulation of gas or environmentally friendly emission.

[0049] In detail, during use, recycled lead electrolytic ingot slag is filled into the grinding chamber 11 through the feed inlet 12 and guided to the grinding assembly 14 by the conical protrusion 15 and the inclined structure 17. Then, the grinding roller 142 rotates with the shaft 141, causing the recycled lead electrolytic ingot slag to gradually enter the grinding gaps formed by multiple first grinding blocks 143 and multiple second grinding blocks 144 for multi-stage grinding. Then, airflow is introduced through the air inlet channel 161, and airflow is ejected from the first jet nozzle 162 to blow the recycled lead electrolytic ingot slag and tumble it. The material is used to improve the grinding effect, and the lead powder is fluidized and transported in time, so that the lead powder is blown to the inclined structure 17 and the lower inclined surface of the conical protrusion 15 in sequence. Finally, the lead powder with a larger mesh size returns to the grinding component 14 for grinding under the resistance and gravity of the conical protrusion 15. The lead powder with a qualified mesh size is guided to the second air nozzle 163 through the lower inclined surface of the conical protrusion 15. Then, the airflow ejected from the second air nozzle 163 blows the lead powder to the upper inclined surface of the conical protrusion 15, and then guides it upward to form secondary fluidization.

[0050] It should be noted that the air intake channel 161 is connected to an external air supply mechanism via a rotary joint to achieve high-pressure air supply; in addition, the rotary joint, the air supply mechanism, and the dust collector 165 themselves and their installation methods are all existing technologies, and will not be described in detail here.

[0051] Furthermore, such as Figures 2-4 as well as Figures 7-11 As shown, the separation mechanism 2 includes multiple conical covers 21 arranged vertically and spaced above the second jet port 163 in the grinding chamber 11, with their inner diameters gradually decreasing from top to bottom; separation chambers 22 formed between two adjacent conical covers 21 and respectively connected to the corresponding discharge ports 13; discharge assembly 23 disposed in the grinding chamber 11; first screening holes 24 formed on the upper end face of the conical covers 21; and second screening holes 25 formed on the side wall of the conical covers 21. The mesh size of the first screening holes 24 is smaller than that of the second screening holes 25. The mesh size of the first screening holes 24 on the multiple conical covers 21 gradually decreases from top to bottom, thereby enabling each separation chamber 22 to separate lead powder within each mesh size range.

[0052] In this embodiment, by setting a conical cover 21 to match the mesh size difference between the first sieve hole 24 and the second sieve hole 25, only sufficiently fine lead powder can flow upward through the first sieve hole 24 and the second sieve hole 25. The lead powder of the current mesh size is guided by the lower surface of the conical cover 21 to the corresponding first sieve hole 24 and enters the corresponding separation chamber 22. After that, it is separated by being guided outward by the upper surface of the conical cover 21. The efficiency and accuracy of the graded separation are extremely high. At the same time, the discharge component 23 is used to discharge the graded lead powder in each separation chamber 22 to the corresponding discharge port 13.

[0053] Furthermore, such as Figures 2-4 as well as Figures 7-11 As shown, the discharge assembly 23 includes multiple third jet ports 231 with one end connected to the air inlet channel 161 and the other end passing through the bottom of multiple conical hoods 21, a control valve 232 disposed between the second jet port 163 and the third jet port 231 and used to control the opening and closing of the air inlet channel 161, multiple discharge plates 233 disposed on the shaft 141 and used to push the lead powder in each separation chamber 22 into the discharge port 13, multiple storage bins 234 respectively connected to the multiple discharge ports 13, and spray pipes 235 that are opened and closed on each discharge bin and connected to each reaction chamber 32.

[0054] In this embodiment, by setting a third jet nozzle 231 in conjunction with a control valve 232, fluidized sieving of lead powder in each separation chamber 22 is achieved, further improving the separation accuracy. In conjunction with the discharge plate 233, the lead powder is pushed through the discharge port 13 into the storage silo 234 for temporary storage, and the conical cover 21 is scraped to avoid blockage. At the same time, the spray pipe 235, in conjunction with the airflow, sprays the lead powder in the storage silo 234 into the reaction chamber 32, improving uniformity and facilitating subsequent reactions.

[0055] In detail, during use, the third jet nozzle 231 further fluidizes the lead powder fluidized by the second jet nozzle 163, allowing the lead powder to pass smoothly through the first sieve hole 24 and / or the second sieve hole 25; then, the control valve 232 controls the air inlet channel 161 to close, preventing the lead powder at the bottom of the grinding chamber 11 from fluidizing, and the third jet nozzle 231 continues to spray air to fluidize and sieve the lead powder in each separation chamber 22; then, the discharge port 13 is opened and the air outlet channel 164 is closed, and the speed at which the lead powder is discharged into the storage silo 234 is increased by the pushing of the pusher plate and the blowing of the third jet nozzle 231; finally, after the previous preparation process is completed, the discharge port 13 and the spray pipe 235 are opened simultaneously, and the airflow blows the lead powder in the storage silo 234 into the spray pipe 235 and then into the reaction chamber 32.

[0056] It should be noted that this application does not limit the specific structure of the storage silo 234. The following only provides one structure for limitation. For example, the upper end of the storage silo 234 is provided with an air outlet channel 164 and a dust collector 165 with the same structure as the grinding chamber 11. The discharge port 13 is connected to the bottom of the storage silo 234. The lower end of the storage silo 234 is provided with a guide slope to guide the lead powder to the discharge port 13, so that the airflow in the discharge port 13 can blow up the lead powder and realize the lead powder is sprayed out from the spray pipe 235. In addition, the control valve 232 and the spray pipe 235 themselves and their installation methods are all existing technologies and will not be described in detail here.

[0057] Furthermore, such as Figures 12-13As shown, both the dissolving mechanism 3 and the generating mechanism 4 include a reaction chamber 31, multiple reaction chambers 32 formed in the reaction chamber 31, an adding component 33 disposed on the reaction chamber 32, a temperature control component 34 disposed between the multiple reaction chambers 32, and multiple filtration components 35 disposed on one side of the reaction chamber 31.

[0058] In this embodiment, multiple reaction chambers 32 are formed within the reaction chamber 31 to process lead powder within different mesh sizes. This facilitates the subsequent addition of components 33 to adjust the acid concentration and pH value, and also allows the temperature control component 34 to adjust the reaction temperature. As a result, each reaction chamber 32 reaches the most suitable conditions for lead powder of that particle size, maximizing the lead recovery rate.

[0059] It should be noted that the addition of component 33 and its installation method are existing technologies, and will not be described in detail here.

[0060] Furthermore, such as Figure 15 As shown, the drying mechanism 5 includes a drying chamber 51, a plurality of drying chambers 52 formed in the drying chamber 51 and each equipped with a temperature control component 34, a conveying component 53 disposed in the drying chamber 52, and a plurality of partitions 54 spaced apart on the conveying component 53.

[0061] In this embodiment, multiple drying chambers 52 are formed within the drying chamber 51 to dry lead powder within different mesh sizes. This allows the temperature control component 34 to adjust the drying temperature of each drying chamber 52 to maximize the drying effect of lead iodide. Simultaneously, the conveying component 53 and the partition 54 are used to convey the lead powder, ensuring that lead powder added at different times or in different batches will not mix on the conveying component 53, maintaining independence and batch clarity.

[0062] It should be noted that the specific structure of the recrystallization mechanism 6 is not limited. The internal structure of the recrystallization mechanism 6 can be the same as that of the dissolution mechanism 3 and the generation mechanism 4. However, the recrystallization mechanism 6 is fed and discharged through the conveying component 53, which is not shown in the attached figure. In addition, the conveying component 53 can be a conveyor belt. Its own and installation method are existing technologies and will not be described in detail here.

[0063] Furthermore, such as Figures 12-15As shown, the temperature control assembly 34 includes a heater 341 disposed outside the reaction chamber 31 for heating and conveying the heat transfer liquid, a first heating pipe 342 connected to the heater 341 and arranged in an S-shape on the outside of the bottom of a plurality of reaction chambers 32 of the dissolution mechanism 3, a second heating pipe 343 connected to the first heating pipe 342 and arranged in an S-shape on the side wall of a plurality of drying chambers 52, a blower 344 disposed on the side wall of the drying chamber 52 for blowing hot air outside the second heating pipe 343 into the drying chamber 52, and a third heating pipe 345 connected at one end to the second heating pipe 343 and arranged in an S-shape on the outside of the bottom of a plurality of reaction chambers 32 of the generation mechanism 4 and then connected to the heater 341.

[0064] In this embodiment, the temperature of the heat transfer fluid is controlled by setting a heater 341 to achieve temperature regulation. In conjunction with the S-shaped arrangement of the first heating tube 342, the second heating tube 343 and the third heating tube 345, the heat transfer efficiency and effect are improved. At the same time, the air blower 344 is used to control the air volume to achieve temperature regulation in the drying chamber 52, and moisture can be removed in time to improve the drying effect and efficiency.

[0065] It should be noted that the first heating tube 342 and the third heating tube 345 are respectively moved and disposed outside the reaction chamber 32 of the dissolving mechanism 3 and the reaction chamber 32 of the generating mechanism 4, so as to facilitate the adjustment of the distance to change the amount of heat transfer and to facilitate the control of temperature; the heater 341 itself and the installation method are existing technologies and will not be described in detail here.

[0066] Furthermore, such as Figures 12-14 As shown, the filtration assembly 35 includes multiple filtration pipes 351 that are openable and closable on the reaction chamber 31 and respectively connected to multiple reaction chambers 32, filters 352 disposed on the filtration pipes 351, multiple chamber doors 353 that are rotatably disposed on the reaction chamber 31 and respectively used to control the opening and closing of the multiple reaction chambers 32, and pusher plates 354 that are movable and rotatably disposed in the reaction chambers 32.

[0067] In this embodiment, by setting up a suction pipe 351 in conjunction with a filter 352, the mixed solution in the reaction chamber 32 is filtered. At the same time, the opening of the chamber door 353 and the pushing of the pusher plate 354 are used to discharge the solid formed after the reaction.

[0068] In detail, during use, the suction pipe 351 is closed, and the discharge port 13, under the action of high-pressure airflow, blows the lead powder in the grinding mechanism 1 into the reaction chamber 32, increasing the air pressure in the reaction chamber 32 and heating the temperature of the solution in the reaction chamber 32 to the reaction temperature; then the discharge port 13 is closed, the temperature control component 34 controls the temperature of the reaction chamber 32, and in conjunction with the pusher plate 354, a stirring effect is achieved, increasing the reaction rate; then, after the reaction is complete and the temperature control component 34 controls the temperature of the reaction chamber 32, the pusher plate 354 stops rotating, the suction pipe 351 is opened, and under the high pressure in the reaction chamber 32, the initial suction filtration process is achieved in conjunction with the filter 352; finally, after the suction pipe 351 and the filter 352 further complete the suction filtration process, the chamber door 353 is opened, and the pusher plate 354 discharges the solid reaction product.

[0069] It should be noted that the filtration tube 351 uses a water pump to draw the solution into the filter 352 for filtration; the filtration tube 351 and the filter 352 themselves and their installation methods are existing technologies and will not be described in detail here.

[0070] In the description of this invention, it should be understood that the terms "front and back", "left and right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0071] Of course, those skilled in the art should understand that the term "a" should be understood as "at least one" or "one or more". That is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. The term "a" should not be understood as a limitation on the quantity.

[0072] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art under the technical guidance of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag, characterized in that, Includes the following steps: Step 1: Grinding process. The recycled lead electrolytic casting slag is ground into lead powder with a particle size controlled at 10-40 mesh by a grinding mechanism. Then, the lead powder in each mesh range is separated into the reaction chambers of the dissolving mechanism by a separation mechanism. Step 2: Dissolution process. The temperature inside the dissolution mechanism is controlled at 40-60℃. After slowly adding acetic acid solution with a mass percentage of 30-60% into the reaction chamber, the temperature inside the dissolution mechanism is controlled at 260-300℃. Nitric acid and deionized water are added at the same time to promote the complete reaction of lead metal in lead powder. Step 3: Generation process. After filtering the mixed solution formed by the reaction in the dissolving mechanism to obtain lead nitrate solution, the lead nitrate solution is added dropwise to the sodium iodide solution in the generation mechanism. During the dropwise addition process, the pH of the mixed solution is maintained at 1-3, and the temperature in the generation mechanism is controlled at 50-60℃ for 2-3 hours to obtain lead iodide mixed solution. Step 4: Drying process. The lead iodide mixture is washed and filtered with deionized water. The resulting moist lead iodide is then transported to the drying unit and dried at 60-80°C for 4-6 hours to obtain crude lead iodide. The crude lead iodide is then added to the recrystallization unit for recrystallization. The resulting moist crystals are then transported to the drying unit and dried at 60-80°C for 4-6 hours to obtain high-purity lead iodide.

2. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag according to claim 1, is characterized in that, The grinding mechanism includes a grinding chamber with an inclined bottom, a feed inlet that opens and closes on the side wall of the grinding chamber, multiple discharge outlets that open and close on the side wall of the grinding chamber, a grinding assembly that is rotatably disposed at the bottom of the grinding chamber, a conical protrusion disposed on the inner wall of the grinding chamber for guiding lead powder to the grinding assembly, and a fluidizing assembly disposed in the grinding chamber for blowing lead powder to form a fluidized state.

3. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag according to claim 2, is characterized in that, The grinding assembly includes a shaft rotatably disposed in the grinding chamber, a grinding roller disposed on the shaft and forming a grinding zone with the inclined structure, a plurality of first grinding blocks spaced apart in the vertical direction on the inclined structure, and a plurality of second grinding blocks spaced apart in the vertical direction on the grinding roller and respectively located between a plurality of adjacent first grinding blocks.

4. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag according to claim 3, is characterized in that, The fluidizing assembly includes an air inlet channel formed inside the shaft, a plurality of first jet ports with one end connected to the air inlet channel and the other end extending through to the space between two second grinding blocks, a plurality of second jet ports with one end connected to the air inlet channel and the other end extending through to the outer wall of the shaft at the position corresponding to the conical protrusion, an air outlet channel that opens and closes at the upper end of the grinding chamber, and a dust collector disposed in the air outlet channel.

5. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag according to claim 4, is characterized in that, The separation mechanism includes multiple conical shrouds spaced vertically above the second jet nozzle within the grinding chamber, with their inner diameters gradually decreasing from top to bottom; separation chambers formed between adjacent conical shrouds and respectively connected to the corresponding discharge ports; a discharge assembly disposed within the grinding chamber; a first sieving hole formed on the upper end face of the conical shroud; and a second sieving hole formed on the side wall of the conical shroud. The mesh size of the first sieving hole is smaller than that of the second sieving hole. The mesh size of the first sieving hole on the multiple conical shrouds gradually decreases from top to bottom, thereby enabling each separation chamber to separate lead powder within a specific mesh size range.

6. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic casting slag according to claim 5, is characterized in that, The discharge assembly includes multiple third jet ports, one end of which is connected to the air inlet channel and the other end of which respectively penetrates to the bottom of multiple conical hoods; a control valve disposed between the second jet port and the third jet port and used to control the opening and closing of the air inlet channel; multiple discharge plates disposed on the shaft and used to push the lead powder in each of the separation chambers to the discharge port; multiple storage bins respectively connected to the multiple discharge ports; and a spray pipe disposed on each of the discharge bins and connected to each of the reaction chambers.

7. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag according to claim 1, characterized in that, Both the dissolving mechanism and the generating mechanism include a reaction chamber, multiple reaction chambers formed within the reaction chamber, an adding component disposed on the reaction chamber, a temperature control component disposed between the multiple reaction chambers, and multiple filtration components disposed on one side of the reaction chamber.

8. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag according to claim 7, characterized in that, The drying mechanism includes a drying chamber, multiple drying chambers formed within the drying chamber and each equipped with the temperature control component, a conveying component disposed within the drying chamber, and multiple partitions spaced apart on the conveying component.

9. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag according to claim 8, characterized in that, The temperature control assembly includes a heater disposed outside the reaction chamber for heating and conveying the heat transfer fluid, a first heating pipe connected to the heater and arranged in an S-shape outside the bottom of a plurality of reaction chambers in the dissolution mechanism, a second heating pipe connected to the first heating pipe and arranged in an S-shape on the sidewalls of a plurality of drying chambers, a blower disposed on the sidewalls of the drying chamber for blowing hot air outside the second heating pipe into the drying chamber, and a third heating pipe connected at one end to the second heating pipe and arranged in an S-shape outside the bottom of a plurality of reaction chambers in the generation mechanism and then connected to the heater.

10. The method for preparing lead iodide, a perovskite precursor, from recycled lead electrolytic ingot slag according to claim 7, characterized in that, The filtration assembly includes multiple filtration tubes that are openable and closable on the reaction chamber and respectively connected to multiple reaction chambers, filters disposed on the filtration tubes, multiple chamber doors that are rotatably disposed on the reaction chamber and respectively used to control the opening and closing of multiple reaction chambers, and a pusher plate that is movable and rotatably disposed in the reaction chamber.

Images