A green oxidation purification method for iron phosphate waste

Abstract

The present application provides a green oxidation purification method for iron phosphate waste, which relates to the technical field of data analysis. The method includes: obtaining waste particles through pretreatment of the iron phosphate waste; acquiring a pyrolysis database for pyrolysis optimization analysis to obtain an optimal pyrolysis plan; adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters to obtain a target pyrolysis plan; performing pyrolysis treatment on the waste particles according to the target pyrolysis plan to obtain pyrolysis products, and then performing acid leaching to obtain a product filtrate; and determining and purifying target elements in the purified product filtrate. The present application solves the technical problems in the prior art that due to fixed pyrolysis conditions and lack of adaptive optimization for different characteristics of iron phosphate waste, the purification efficiency is low, the product purity is not high, and the acid leaching extraction effect is affected, and achieves the technical effects of improving the purification efficiency and product purity, reducing the waste liquid discharge and by-products in the acid leaching process, and realizing green and environmental protection purification.

Description

Technical Field

[0001] This application relates to the technical field of data analysis, and specifically relates to a green oxidation and purification method for iron phosphate waste. Background Art

[0002] As a by-product in the production of products such as lithium iron phosphate batteries, iron phosphate waste contains a large amount of valuable elements such as iron and phosphorus. With the development of the new energy industry, the recycling of iron phosphate waste has become an important topic for improving resource utilization efficiency and reducing environmental pollution.

[0003] The existing oxidation and purification methods for iron phosphate waste mainly adopt the method of high-temperature pyrolysis combined with chemical treatment (such as acid leaching and precipitation separation). However, traditional pyrolysis processes usually adopt fixed temperature and atmosphere conditions, and different batches of iron phosphate waste vary in composition and physical properties. Fixed pyrolysis conditions are difficult to adapt to the complex waste characteristics, resulting in low pyrolysis efficiency, ineffective removal of some impurities, affecting the purification effect, and causing loss of target elements or formation of by-products. In addition, due to incomplete pyrolysis, more chemical reagents are required in the subsequent acid leaching process, increasing the waste liquid discharge and treatment costs. Summary of the Invention

[0004] This application provides a green oxidation and purification method for iron phosphate waste, which solves the technical problems in the prior art that due to fixed pyrolysis conditions and lack of adaptive optimization for the characteristics of different iron phosphate wastes, the purification efficiency is low, the product purity is not high, and the subsequent acid leaching extraction effect is affected. Through data-driven optimization analysis, the pyrolysis conditions are optimized, achieving the technical effects of improving the purification efficiency and product purity, reducing the waste liquid discharge and by-products in the acid leaching process, and realizing green and environmentally friendly oxidation and purification.

[0005] In view of the above problems, this application provides a green oxidation and purification method for iron phosphate waste. The method includes: treating the iron phosphate waste according to a pretreatment strategy to obtain waste particles; obtaining a pyrolysis database, and performing pyrolysis optimization analysis on the pyrolysis database to obtain an optimal pyrolysis plan; adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles to obtain a target pyrolysis plan; performing pyrolysis treatment on the waste particles according to the target pyrolysis plan to obtain a pyrolysis product, and acid leaching to obtain a product filtrate; activating an inductively coupled plasma optical emission spectrometer to perform determination and purification of target elements on the purified product filtrate.

[0006] One or more technical solutions provided in this application have at least the following beneficial effects:

[0007] By pre-treating iron phosphate waste, a suitable granular state is provided for subsequent pyrolysis treatment, ensuring uniform heating of the waste during pyrolysis and improving the treatment efficiency. Obtain a pyrolysis database and conduct pyrolysis optimization analysis to obtain an optimal pyrolysis plan. This step optimizes pyrolysis conditions based on a data-driven method, avoiding the problems of fixed pyrolysis parameters and poor adaptability in traditional methods and improving pyrolysis efficiency. Combine the target particle characteristic parameters of the waste particles to adjust the optimal pyrolysis plan to obtain a target pyrolysis plan. This step can be customized and optimized according to the physical and chemical properties of different batches of waste, enhancing the adaptability and flexibility of the plan and further improving the purification efficiency. Pyrolyze the waste particles according to the target pyrolysis plan, use the optimized pyrolysis conditions to effectively remove impurities, obtain pyrolysis products, improve the extraction efficiency of target elements, and further purify by combining acid leaching. Use an inductively coupled plasma emission spectrometer to determine and purify the target elements in the purified product filtrate, detect the content of target elements, ensure that the purity of the purified product meets the requirements, and further improve the product purity.

[0008] In summary, through optimizing the pyrolysis conditions and acid leaching process, this application adaptively adjusts pyrolysis conditions according to different wastes, combines advanced detection technologies, realizes green oxidative purification of iron phosphate waste, improves the purification efficiency of iron phosphate waste, enhances the product purity, simultaneously improves the subsequent acid leaching extraction effect, reduces unnecessary by-products, and reduces the environmental pollution risk, providing a feasible technical route for the green and efficient recycling of iron phosphate waste.

[0009] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following specifically gives the specific embodiments of this application. Brief Description of the Drawings

[0010] Figure 1 It is a schematic flow chart of a method for green oxidative purification of iron phosphate waste provided by an embodiment of this application.

[0011] Figure 2 It is a schematic flow chart of obtaining an optimal pyrolysis plan in a method for green oxidative purification of iron phosphate waste provided by an embodiment of this application.

[0012] Figure 3 It is a schematic flow chart of obtaining a target pyrolysis plan in a method for green oxidative purification of iron phosphate waste provided by an embodiment of this application. Detailed Description of the Invention

[0013] By providing a green oxidation and purification method for iron phosphate waste in the embodiments of the present application, the technical problems in the prior art are solved. Due to the fixed pyrolysis conditions and the lack of adaptive optimization for the characteristics of different iron phosphate wastes, the purification efficiency is low, the product purity is not high, and the subsequent acid leaching extraction effect is affected. Through data-driven optimization analysis, the pyrolysis conditions are optimized, achieving the technical effects of improving the purification efficiency and product purity, while reducing the waste liquid discharge and by-products in the acid leaching process, and realizing green and environmental protection oxidation and purification.

[0014] As Figure 1 shown, the embodiments of the present application provide a green oxidation and purification method for iron phosphate waste, and the method includes:

[0015] Step S1: Treat the iron phosphate waste according to a pretreatment strategy to obtain waste particles.

[0016] Specifically, the pretreatment strategy refers to a series of preliminary treatment methods for the iron phosphate waste before formal purification, such as cleaning, grinding, screening, magnetic separation, etc. The purpose is to remove impurities in the waste, adjust the particle size and shape, and improve the efficiency and effect of subsequent treatment.

[0017] Before formal purification, first evaluate the state of the iron phosphate waste to determine a suitable pretreatment strategy. Exemplarily, for the waste disassembled from used batteries, it may be mixed with impurities such as battery shell fragments and binders. For this situation, the pretreatment strategy includes mechanical crushing to make the waste into smaller particles for subsequent treatment, then using magnetic separation to remove metal shell fragments (magnetic separation tool), and then removing the binder through organic solvent cleaning. After these operations, relatively pure waste particles with appropriate particle size are obtained.

[0018] Through pretreatment, the iron phosphate waste is preliminarily purified, some obvious impurities are removed, and it is transformed into a waste particle form more suitable for subsequent treatment, providing a suitable raw material for subsequent pyrolysis and other operations, and improving the efficiency of the entire recovery and purification process and the purity of the final product.

[0019] Step S2: Obtain a pyrolysis database, and perform pyrolysis optimization analysis on the pyrolysis database to obtain an optimal pyrolysis plan.

[0020] Specifically, the pyrolysis database is a data set that stores the relationships between different pyrolysis conditions (such as temperature, atmosphere, time, etc.) and treatment effects (such as product purity, target element recovery rate, etc.). Relevant data on the pyrolysis of iron phosphate waste are collected from literature, experiments, and industrial production to establish the pyrolysis database. For example, collect data on the composition and purity of pyrolysis products under different temperatures (300 °C to 800 °C), times (0.5 hours to 4 hours), and atmospheres (nitrogen, argon, etc.). Use statistical analysis software (such as Excel, SPSS) to preliminarily analyze the collected data to understand the influence trends of various parameters on the pyrolysis effect. For example, by plotting the relationship curve between temperature and product purity, preliminarily determine the optimal temperature range. Apply optimization algorithms (such as genetic algorithms, simulated annealing algorithms) to optimize the pyrolysis conditions to find the pyrolysis conditions such as pyrolysis temperature, pyrolysis time, and pyrolysis atmosphere with the highest product purity, and obtain the optimal pyrolysis plan. For example, use the genetic algorithm, set the population size to 50, the number of iterations to 100, the crossover probability to 0.8, and the mutation probability to 0.1 to find the best combination of temperature, time, and atmosphere.

[0021] By obtaining and analyzing the pyrolysis database, using data analysis methods, the optimal solution is found from numerous pyrolysis condition combinations, providing the best condition plan for subsequent pyrolysis operations, which helps improve the quality of pyrolysis products, thereby enhancing the purity of the final product and the efficiency of the entire purification process.

[0022] Step S3: Adjust the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles to obtain the target pyrolysis plan.

[0023] Specifically, the target particle characteristic parameters are parameters that describe the specific characteristics of the waste particles, such as particle size distribution, density, shape, etc. These parameters will affect the effect of the pyrolysis process, and the optimal pyrolysis plan needs to be adjusted accordingly to adapt to different batches of waste particles. The target pyrolysis plan is the final pyrolysis plan obtained by adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles themselves.

[0024] First, use test instruments to precisely measure the waste particles to obtain their target particle characteristic parameters. For example, use a laser particle size analyzer to measure the particle size distribution of the waste particles, and use a density tester to measure the density of the waste particles. The pyrolysis time in the optimal pyrolysis plan is set according to general conditions. It is necessary to adjust the pyrolysis conditions such as temperature, time, and heating rate in the optimal pyrolysis plan according to the measured particle characteristic parameters. For example, larger particles may require higher temperatures or longer times for complete reaction, while smaller particles may require lower temperatures to avoid sintering. Exemplarily, for a batch of waste particles with larger particle sizes and irregular shapes, by analyzing their characteristic parameters, the temperature in the optimal pyrolysis plan is adjusted from 600 °C to 650 °C, and the time is adjusted from 2 hours to 2.5 hours. The obtained target pyrolysis plan can better meet the pyrolysis requirements of this batch of particles.

[0025] Adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles can make the pyrolysis conditions more precisely match waste particles of different batches and characteristics, improve the adaptability and flexibility of pyrolysis treatment, and further enhance the purification effect.

[0026] Step S4: Perform pyrolysis treatment on the waste particles according to the target pyrolysis plan to obtain pyrolysis products, and then perform acid leaching to obtain product filtrates.

[0027] Specifically, use pyrolysis equipment such as tube furnaces and box furnaces to set parameters such as temperature, time, heating rate, and atmosphere according to the target pyrolysis plan. Place the waste particles in the pyrolysis equipment to carry out pyrolysis reactions to remove organic impurities and obtain pyrolysis products. Then use equipment such as reaction kettles and beakers to perform acid leaching operations. Use acidic solutions (such as sulfuric acid, hydrochloric acid, etc.) to carry out chemical reactions with the pyrolysis products to dissolve target elements (such as iron, phosphorus, etc.) into the solution to obtain product filtrates for subsequent separation and purification. Add the pyrolysis products to the acid leaching equipment to carry out acid leaching reactions to obtain product filtrates. Exemplarily, set the temperature in the tube furnace to 650 °C, the heating rate to 10 °C / min, the time to 2.5 hours, and introduce nitrogen as the pyrolysis atmosphere. Place the waste particles in a quartz boat, push it into the tube furnace, and heat and keep warm according to the set program. After the pyrolysis reaction is completed, cool it naturally to room temperature to obtain pyrolysis products. Then place the pyrolysis products in a reaction kettle for acid leaching. Add sulfuric acid solution according to a liquid-solid ratio of 10:1, with a stirring speed of 300 rpm and a temperature of 80 °C, and a reaction time of 2 hours, so that iron ions, phosphate ions, etc. in the pyrolysis products are fully dissolved in the acid solution to obtain product filtrates.

[0028] The waste particles are converted into pyrolysis products through pyrolysis treatment, and further, the target elements in the pyrolysis products are extracted into the product filtrates through acid leaching, providing raw materials for subsequent determination and purification.

[0029] Step S5: Activate an inductively coupled plasma optical emission spectrometer to measure and purify the target elements in the purified product filtrate.

[0030] Specifically, an inductively coupled plasma optical emission spectrometer is a high-precision spectral analysis instrument that can perform rapid and accurate quantitative analysis of multiple elements. Purification is a pretreatment of the product filtrate to remove suspended solids, organic matter and other impurities, improving the purity of the solution for subsequent element determination and purification. Methods such as filtration, centrifugation, and activated carbon adsorption are used to purify the product filtrate. Turn on the inductively coupled plasma optical emission spectrometer and perform operations such as preheating and calibration of the instrument to ensure that the instrument is in the best working condition. For example, preheat for 30 minutes, calibrate using a standard solution, and set parameters such as radio frequency power and observation height. Measure the purified product filtrate according to the instrument operation procedure to obtain the content and composition of the target elements, including the content of iron, phosphorus, lithium, and impurity elements, and analyze its purity and ratio. According to the measurement results, further purification treatment is carried out on the product filtrate, such as evaporation crystallization, ion exchange, solvent extraction, etc., to remove the impurity elements and improve the purity of the target elements.

[0031] Exemplarily, first filter the suspended solids in the product filtrate with a 0.45 μm filter membrane, then adsorb the organic matter with activated carbon, and finally clarify the solution by centrifugation. Next, use an inductively coupled plasma optical emission spectrometer to measure the content of iron, phosphorus, lithium, and impurity elements and analyze their purity and ratio. According to the test results, it is found that the purity of iron ions is not high enough. After analysis, it is found that there are calcium ion impurities. Chemical precipitation methods (such as adding sodium carbonate to form calcium carbonate precipitate) can be used to remove the impurities and improve the purity of the product.

[0032] By using an inductively coupled plasma optical emission spectrometer to measure and purify the target elements in the purified product filtrate, the composition and purity of the product can be accurately analyzed and controlled to ensure that the quality of the final product meets the standard requirements.

[0033] Furthermore, the pretreatment strategy in Step S1 refers to the strategy of crushing, screening, and cleaning the iron phosphate waste.

[0034] Specifically, crushing refers to the process of decomposing larger pieces of iron phosphate waste into smaller particles by mechanical force. Through the crushing operation, the particle size of the iron phosphate waste is reduced, increasing the specific surface area of the waste. In subsequent pyrolysis and other treatment processes, the contact area between the waste and the reaction medium increases, and the reaction is more sufficient, which is conducive to improving the treatment efficiency. In actual operation, equipment such as jaw crushers or ball mills can be used for crushing.

[0035] Screening is an operation that separates the crushed iron phosphate waste according to particle size. The tool used is a sieve mesh. Sieve meshes of different mesh numbers can screen out waste particles within different particle size ranges, ensuring that the waste particles for subsequent processing have a relatively uniform particle size. During the subsequent processing, it can make the reaction more stable and controllable, avoid uneven reactions caused by excessive differences in particle size, and improve the purity of the final product.

[0036] Cleaning is to remove impurities on the surface of the iron phosphate waste, such as dust, oil stains, etc. Organic solvents (such as ethanol, acetone, etc.) or water can be used for cleaning. If there are oil stains on the waste surface, organic solvents have a better cleaning effect; if they are water-soluble impurities such as dust, water can be used for cleaning. During the pyrolysis process, impurities will affect the quality of the pyrolysis products. After cleaning, the purity of the pyrolysis products can be improved, thereby enhancing the quality of the entire iron phosphate waste oxidation and purification process.

[0037] For iron phosphate waste from different sources and in different states, different pretreatment strategies are selected. Exemplarily, for iron phosphate waste from a used battery production workshop, the surface is contaminated with lubricating oil and a small amount of dust during the battery production process. Use a jaw crusher to initially crush the large iron phosphate waste into small pieces with a diameter of about 1 cm to 2 cm, and then further grind it with a ball mill to make the particle size reach 0.5 mm to 1 mm; during the screening process, first use a 20-mesh sieve mesh for rough screening, and then use an 80-mesh sieve mesh for fine screening to screen out waste particles with a particle size between 0.18 mm and 0.5 mm; during the cleaning process, use acetone as the cleaning solvent, soak the screened waste particles in the acetone solution for 15 minutes, and then rinse with clean water to obtain the pretreated waste particles.

[0038] For iron phosphate waste recycled from outdoor used equipment, there is a large amount of dust and a small amount of rust on its surface caused by rain erosion. First, use a cone crusher to crush it into fragments with a diameter of about 0.5 cm to 1 cm, and then perform secondary crushing through a rod mill to make the diameter of the waste particles reach 0.3 cm to 0.5 cm. During the screening process, first use a 10-mesh sieve mesh for the first screening, and then use a 50-mesh sieve mesh for the second screening. During the cleaning process, first use a high-pressure water gun to wash the waste to remove most of the dust and rust, and then soak and clean the waste particles with ethanol for 5 minutes to remove the remaining oil stains and impurities, completing the pretreatment.

[0039] Further, as Figure 2 shown, step S2 includes:

[0040] Step S21: Extract the first pyrolysis record from the pyrolysis database.

[0041] Step S22: Conduct multi-dimensional evaluation and analysis on the first pyrolysis product in the first pyrolysis record to obtain the first pyrolysis thoroughness index.

[0042] Step S23: If the first pyrolysis completeness index reaches a predetermined index threshold, extract the first pyrolysis parameters from the first pyrolysis record.

[0043] Step S24: Form the optimal pyrolysis plan based on the first pyrolysis parameters.

[0044] Specifically, in the pyrolysis database, select a record as the first pyrolysis record in a certain order (such as in the order of record numbers or storage time, etc.).

[0045] The pyrolysis completeness index is an indicator for comprehensively evaluating the quality of pyrolysis products, which is determined by evaluating the pyrolysis products from multiple different perspectives or dimensions. For the first pyrolysis products in the first pyrolysis record, use a variety of analytical instruments and methods for multi-dimensional evaluation and analysis, measure the component contents of different forms of pyrolysis products, and calculate the first pyrolysis completeness index according to the measurement results, certain weights, and formulas.

[0046] The predetermined index threshold is a pre-set minimum standard for the pyrolysis completeness index, used to judge whether the pyrolysis products meet the quality requirements. For example, the predetermined index threshold can be set to 80 points. Compare the calculated first pyrolysis completeness index with the predetermined index threshold. If the first pyrolysis completeness index reaches or exceeds the predetermined index threshold, extract the first pyrolysis parameters (such as temperature, time, atmosphere, etc.) from the first pyrolysis record. When the first pyrolysis completeness index does not reach the predetermined index threshold, discard the corresponding first pyrolysis record, then extract a new pyrolysis record from the pyrolysis database for evaluation and analysis, and repeat this pyrolysis record selection and evaluation process until pyrolysis parameters that reach or exceed the predetermined index threshold are found.

[0047] Integrate the extracted first pyrolysis parameters into a complete pyrolysis plan, including specific parameters such as the temperature, time, and atmosphere of pyrolysis. According to the actual situation such as equipment performance and raw material characteristics, appropriately optimize and adjust the parameters in the plan. For example, through experimental verification and data analysis, slightly adjust the temperature or time to adapt to specific production conditions. Exemplarily, the extracted first pyrolysis parameters are a temperature of 600 °C, a time of 2 hours, and an atmosphere of nitrogen. Prepare the optimal pyrolysis plan based on these parameters, and in combination with the actual performance of the equipment, adjust the temperature to 590 °C and the time to 2.5 hours to ensure the stability and effect of the pyrolysis process.

[0048] The above steps extract high-quality pyrolysis records from the pyrolysis database, screen out pyrolysis parameters that meet the quality requirements through multi-dimensional evaluation, and finally form an optimal pyrolysis plan. This process effectively utilizes historical data and data evaluation methods, provides reliable operation guidance for the pyrolysis treatment of iron phosphate waste, and ensures the high efficiency of the pyrolysis process and the high quality of the products.

[0049] Further, step S22 includes:

[0050] Step S221: Activate the inductively coupled plasma optical emission spectrometer to perform determination and analysis of the target elements on the first pyrolysis product to obtain the first element content.

[0051] Step S222: Activate the gas chromatograph to perform determination and analysis of the pyrolysis gas in the first pyrolysis product to obtain the first gas content.

[0052] Step S223: Introduce a pyrolysis evaluation function to evaluate and analyze the first element content and the first gas content to obtain the first pyrolysis thoroughness index.

[0053] Specifically, perform appropriate pretreatment on the first pyrolysis product, such as grinding it into fine powder, and then dissolve it in an appropriate acidic solution to prepare a solution sample suitable for analysis by the inductively coupled plasma optical emission spectrometer. For example, grind the pyrolysis product to less than 200 mesh, add a mixed acid of nitric acid and hydrochloric acid for dissolution, and filter and make up the volume to a certain volume after filtration. Turn on the inductively coupled plasma optical emission spectrometer and perform preheating and calibration operations to ensure that the instrument is in the best working condition. Introduce the prepared solution sample into the inductively coupled plasma optical emission spectrometer to perform determination and analysis of the target elements to obtain the first element content. Among them, the first element content includes the contents of iron, phosphorus, and lithium elements.

[0054] Collect the pyrolysis gas in the first pyrolysis product using a gas sampling bag or a gas syringe. For example, after the pyrolysis reaction ends, quickly collect the generated gas with a gas sampling bag to avoid gas leakage and loss. Turn on the gas chromatograph and perform preheating and calibration operations to ensure the separation and detection performance of the instrument. For example, preheat for 1 hour, calibrate using a standard gas mixture, and set appropriate column temperature, carrier gas flow rate and other parameters. Inject the collected pyrolysis gas sample into the gas chromatograph for separation and quantitative analysis to obtain the first gas content, such as the volume contents of carbon dioxide, carbon monoxide, hydrogen, methane and other gases.

[0055] The pyrolysis evaluation function is a mathematical model that comprehensively considers the element content and gas content, and is used to evaluate the quality of pyrolysis products and the thoroughness of the pyrolysis reaction. This function is a formula containing multiple weighted terms. Different weight coefficients are set according to the importance of the target elements and pyrolysis gases in the evaluation of pyrolysis thoroughness, and then calculations are performed to obtain the first pyrolysis thoroughness index. According to the requirements of the purification process and the characteristics of the pyrolysis products, the specific evaluation indicators and weight distributions in the pyrolysis evaluation function are determined. For example, the weight of the element content is set to 0.6, and the weight of the gas yield is set to 0.4. Based on the determined evaluation indicators and weights, the pyrolysis evaluation function is constructed, and the first element content and the first gas content are substituted into the function for calculation to obtain the first pyrolysis thoroughness index.

[0056] The pyrolysis evaluation function comprehensively evaluates and analyzes the first element content and the first gas content to obtain the first pyrolysis thoroughness index. This index can quantify the thoroughness of pyrolysis, providing an intuitive and scientific basis for subsequent judgment on whether to adopt the parameters in this pyrolysis record, helping to screen out the most suitable pyrolysis conditions, and improving the efficiency of the entire iron phosphate waste oxidation purification process and the purity of the final product.

[0057] Furthermore, the formula of the pyrolysis evaluation function is: Wherein, represents the first pyrolysis thoroughness index, represents the measured content of the th element in the first element content, represents the loss coefficient of the measured content of the th element, and the first element content includes the first lithium element content, the first phosphorus element content, and the first iron element content, represents the content of the th element in the waste particles, represents the weight coefficient of the th element, represents the weight coefficient of the first gas content, represents the measured value of the first gas content, represents the estimated volume of potentially gas-generable gas in the waste particles, represents the loss coefficient of the measured value of the first gas content.

[0058] Specifically, this formula mainly consists of two parts. The first part is the evaluation of the solid part (element content). Considering element loss, it evaluates the recovery rates of key elements such as lithium, phosphorus, and iron after pyrolysis. Among them, represents the The measured contents of the elements, including the first lithium element content, the first phosphorus element content, and the first iron element content, are obtained by measuring and analyzing the first pyrolysis product using an inductively coupled plasma optical emission spectrometer. Characterize the Loss coefficient of the measured content of the element, which is used to measure the possible loss degree of the element during pyrolysis. The value range is between 0 and 1. The smaller the value, the less the element loss. It can be determined according to experimental data and literature, and is usually estimated by measuring the element loss rate under different conditions through experiments. Characterize the Content of the element in the waste particles as a reference value, which is obtained by elemental analysis of the original waste particles using an inductively coupled plasma optical emission spectrometer. Characterize the Weight coefficient of the element, which represents the importance of a certain element in the thorough evaluation of pyrolysis. The larger the value, the greater the contribution of the element to the final purification quality. It is preset according to the requirements of the purification process and the importance of the element. For example, the weight coefficients of lithium, phosphorus, and iron are 0.4, 0.3, and 0.3 respectively. The closer the calculation result of the first part is to 1, the higher the recovery rate of the target element.

[0059] The second part of the formula Is the evaluation of the gas part (pyrolysis gas). The rationality of gas release during pyrolysis is measured by the ratio of the generation of pyrolysis gas to the theoretical value, that is, whether the actual gas release amount is consistent with the theoretical expectation. Among them, Characterize the weight coefficient of the first gas content, which represents the influence degree of the gas on the thoroughness of the whole pyrolysis. It is preset according to the importance of the gas in the evaluation. For example, it can be set to 0.2. Characterize the measured value of the first gas content, which is obtained by measuring and analyzing the pyrolysis gas using a gas chromatograph (GC), and is expressed in volume or mole number. Characterize the estimated value of the volume of gas that can potentially be generated in the waste particles, which is expressed in volume or mole number and is used as a reference value. It can be estimated according to the characteristics of the waste particles and pyrolysis conditions, and can be obtained through experiments or literature review. Characterize the loss coefficient of the measured value of the first gas content, which is used to measure the possible loss degree of the gas during pyrolysis. It is determined according to experimental data and literature, and is usually estimated by measuring the gas loss rate under different conditions through experiments.

[0060] This pyrolysis evaluation function can comprehensively consider various factors such as the elemental content and gas content in the pyrolysis products to comprehensively evaluate the thoroughness of the pyrolysis process. By setting weight coefficients for different elements and gases, the influence of certain key factors on the thoroughness of pyrolysis can be focused on according to actual needs. The calculated first pyrolysis thoroughness index can be used to compare the thoroughness of pyrolysis under different pyrolysis conditions, so as to optimize the pyrolysis process parameters and improve the pyrolysis efficiency and product quality.

[0061] Further, as Figure 3 shown, step S3 includes:

[0062] Step S31: Extract the first waste particles from the first pyrolysis record and obtain the first particle characteristic parameters of the first waste particles.

[0063] Step S32: Compare the target particle characteristic parameters with the first particle characteristic parameters to obtain the first particle deviation.

[0064] Step S33: Use the first particle deviation as an adjustment coefficient to adjust the optimal pyrolysis plan to obtain the target pyrolysis plan.

[0065] Specifically, extract the relevant data of the first waste particles corresponding to the first pyrolysis record from the pyrolysis database. Then, use corresponding measuring instruments and methods to obtain the first particle characteristic parameters of the first waste particles. For example, use a laser particle size analyzer to measure the particle size distribution, use a densitometer or pycnometer method to measure the density of the particles, and observe the shape of the particles through an electron microscope.

[0066] Compare the target particle characteristic parameters with the first particle characteristic parameters one by one, calculate the deviation value of each parameter, and obtain the first particle deviation. According to actual needs, calculation methods such as absolute deviation, relative deviation, and deviation ratio can be used. Exemplarily, the target particle characteristic parameters are a particle size of 120 mesh to 180 mesh, a shape of nearly spherical, and a density of 3.2 g / cm³. While the first particle characteristic parameters are a particle size of 100 mesh to 150 mesh, a shape of irregular polyhedron, and a density of 3.0 g / cm³. Through comparison and calculation, the first particle deviation is a particle size deviation of -20 mesh, a large shape deviation, and a density deviation of -0.2 g / cm³.

[0067] According to the first particle deviation, the corresponding adjustment coefficient is calculated. For example, the particle size deviation can correspond to the adjustment of temperature and time, and the shape deviation can correspond to the adjustment of atmosphere and heating rate, etc. The adjustment coefficient is applied to the optimal pyrolysis plan to adjust the pyrolysis parameters. According to the adjusted pyrolysis parameters, the final target pyrolysis plan is formed. Exemplarily, the adjustment coefficients calculated according to the first particle deviation are a temperature adjustment of +30°C, a time adjustment of +0.5 hours, and an atmosphere adjustment of increasing hydrogen by 5%. Applying these adjustment coefficients to the optimal pyrolysis plan, the original optimal pyrolysis plan is a temperature of 600°C, a time of 2 hours, and an atmosphere of nitrogen. After adjustment, the target pyrolysis plan is a temperature of 630°C, a time of 2.5 hours, and an atmosphere of a mixture of nitrogen and hydrogen (nitrogen accounts for 95% and hydrogen accounts for 5%).

[0068] The above steps calculate the first particle deviation as the adjustment coefficient, adjust the optimal pyrolysis plan to obtain the target pyrolysis plan, making the pyrolysis plan more in line with the actual waste particle characteristics, improving the efficiency and effect of the pyrolysis process, and ensuring that the quality of the pyrolysis products is closer to the expectation.

[0069] Further, the method further includes obtaining predetermined particle characteristics, wherein the predetermined particle characteristics are used to collect characteristics of the first waste particle and the waste particle, and the predetermined particle characteristics at least include average particle size, average density, particle number, and particle shape.

[0070] Specifically, the predetermined particle characteristics are a set of characteristic indexes preset for collecting characteristics of waste particles. These indexes at least include average particle size, average density, particle number, and particle shape, etc., which describe the characteristics of waste particles from different aspects.

[0071] The average particle size reflects the size of the waste particles and is an average measure of the particle size. For particles with regular shapes (such as spherical), the diameter of the particles can be directly measured using an optical microscope or an electron microscope, and then the diameters of multiple particles (for example, randomly selecting 100 particles) are measured and averaged. For particles with irregular shapes, a laser particle size analyzer can be used for measurement. The laser particle size analyzer measures the intensity distribution of the scattered light of the particles by the laser, calculates the equivalent particle size of the particles according to the scattering theory, and then statistically averages the equivalent particle sizes of multiple particles to obtain the average particle size.

[0072] The average density represents the ratio of the average mass to the volume of the waste particles and is an index to measure the compactness of the particulate matter. For particles with regular shapes, the volume can be calculated according to the geometric shape formula; for particles with irregular shapes, the drainage method can be used to calculate the average density. To improve the accuracy, multiple measurements (such as 3 to 5 times) can be repeated and averaged.

[0073] The particle number refers to the number of waste particles within a certain range (such as within a specific sample volume or mass), and this quantity information is of great significance for understanding the total amount of waste and particle distribution, etc. For large-scale waste samples, an automatic counting system based on image recognition technology can be used. First, images of waste particles are collected, and then image recognition algorithms are used to identify and count the particles.

[0074] The particle shape describes the geometric shape of waste particles, such as spherical, cubic, irregular shapes, etc. The particle shape affects characteristics such as the packing method between particles and the flow of fluid between particles. Through microscopic observation (optical microscope or electron microscope), the external shape of the particles is directly observed and classified and described.

[0075] By obtaining predetermined particle characteristics and using them as the basis for feature collection, it can ensure that the waste particle treatment process has clear goals and standards, improve the scientificity and controllability of the entire purification process, and provide guarantee for finally obtaining high-quality purified products.

[0076] Further, step S33 includes:

[0077] Step S331: Read the predetermined pyrolysis characteristics and extract the first pyrolysis characteristic from the predetermined pyrolysis characteristics.

[0078] Step S332: Match the first parameter corresponding to the first pyrolysis characteristic in the optimal pyrolysis plan.

[0079] Step S333: Adjust the first parameter according to the adjustment coefficient to obtain the first adjusted parameter.

[0080] Step S334: Construct the target pyrolysis plan based on the first adjusted parameter.

[0081] Specifically, the predetermined pyrolysis characteristics are a set of characteristic parameters preset for describing and evaluating the pyrolysis treatment effect. These parameters are determined according to the characteristics of iron phosphate waste and the requirements of the purification process, and are used to guide the pyrolysis treatment process. According to the requirements of the purification process and the characteristics of the waste, specific parameters of the predetermined pyrolysis characteristics are defined, such as temperature, time, atmosphere, heating rate, etc. The predetermined pyrolysis characteristics are stored in a database or configuration file for easy reading and extraction. The first pyrolysis characteristic is extracted from the stored predetermined pyrolysis characteristics. For example, the temperature parameter is extracted as the first pyrolysis characteristic.

[0082] The optimal pyrolysis plan includes a series of pyrolysis parameters such as temperature, time, atmosphere, etc. Analyze the optimal pyrolysis plan to extract each pyrolysis parameter. According to the definition of the first pyrolysis feature, find the corresponding first parameter in the optimal pyrolysis plan. Record the value of the matched first parameter for subsequent adjustment operations. By matching the first parameter corresponding to the first pyrolysis feature in the optimal pyrolysis plan, the specific parameter to be adjusted is clarified, providing a basis for subsequent parameter adjustment.

[0083] Perform a mathematical operation on the first parameter according to the adjustment coefficient to obtain the first adjusted parameter. If the adjustment coefficient is a proportional coefficient (e.g., 1.1 means an increase of 10%), then the first adjusted parameter = the first parameter × the adjustment coefficient; if the adjustment coefficient is a difference (e.g., +50°C), then the first adjusted parameter = the first parameter + the adjustment coefficient. Adjust all the parameters in the predetermined pyrolysis feature in the same way to obtain the corresponding multiple first adjusted parameters. Replace the corresponding parameters in the optimal pyrolysis plan with the first adjusted parameters to construct a new pyrolysis plan.

[0084] Through the above steps, the pyrolysis treatment plan can be accurately adjusted according to the characteristics of the actual waste particles to better guide the pyrolysis process and improve the efficiency and product purity of the entire iron phosphate waste oxidation and purification process.

[0085] Furthermore, after pyrolyzing the waste particles according to the target pyrolysis plan to obtain a pyrolysis product and acid-leaching to obtain a product filtrate, it further includes: obtaining the leaching residue and performing harmless treatment on the leaching residue, where the leaching residue refers to the product residue obtained by acid-leaching the pyrolysis product.

[0086] Specifically, the leaching residue is the product residue remaining after acid-leaching the pyrolysis product. During acid-leaching, some components in the pyrolysis product dissolve into the acid solution to form a product filtrate, while the components insoluble in the acid remain to form the leaching residue. The leaching residue may contain some impurities, minerals and other substances that are not dissolved by the acid. After the acid-leaching treatment, the solid and liquid in the acid-leaching system are separated by filtration operation, and the solid part is the leaching residue. Filtering equipment such as Buchner funnels, filter papers, suction flasks, etc. can be used for suction filtration operations, or equipment such as filter presses can be used for filtration. Filter the mixture after acid-leaching the pyrolysis product, and collect the solid substances on the filter paper or the filter plate of the filter press as the leaching residue.

[0087] Next, the leaching residue is subjected to harmless treatment to reduce its environmental pollution. The harmless treatment can be carried out in various ways such as chemical stabilization treatment, solidification treatment, high-temperature treatment, etc. If the leaching residue contains harmful substances such as heavy metals, chemical stabilizers can be added to the leaching residue. For example, for the lead-containing leaching residue, sulfides (such as sodium sulfide) can be added to make lead ions combine with sulfide ions to form lead sulfide precipitation, thereby reducing the leaching toxicity of lead. Solidification treatment is to mix the leaching residue with solidifying agents such as cement, lime, gypsum, etc., so that the leaching residue is wrapped in the solid matrix formed by the solidifying agent to prevent the leakage and diffusion of harmful substances. During the solidification process, the harmful substances in the leaching residue are confined inside the solidified body, reducing their contact and migration with the external environment. A mechanical stirring device can be used to mix the leaching residue and cement evenly in a certain proportion, and then poured into a mold for shaping. After a period of curing, a solidified body is formed. For some leaching residues with a high content of organic pollutants, a high-temperature incineration method can be used. The leaching residue is sent into an incinerator, and at high temperatures (such as 800°C to 1000°C), the organic pollutants are burned and decomposed into harmless substances such as carbon dioxide and water. The incinerator needs to be equipped with a good waste gas treatment system to treat the waste gas generated during the incineration process to prevent secondary pollution. Through the above treatment, the harmfulness and environmental risk of the leaching residue can be effectively reduced, making it meet the relevant environmental protection standards and requirements, and achieving the harmless goal of waste treatment.

[0088] In summary, the green oxidation purification method for iron phosphate waste provided by the embodiments of the present application has the following beneficial effects:

[0089] The embodiments of the present application effectively improve the recovery and purification efficiency of iron phosphate waste through multi-step integration of pretreatment, pyrolysis optimization, acid leaching purification, and precise detection. First, the iron phosphate waste is pretreated. Through operations such as crushing, screening, and cleaning, impurities are effectively removed, the particle size and morphology are adjusted, and uniform waste particles are obtained, laying a good foundation for subsequent processing. Then, a pyrolysis database is obtained and pyrolysis optimization analysis is carried out. Using a data-driven method, the optimal pyrolysis plan is screened out from a large number of pyrolysis records to ensure the scientificity and rationality of pyrolysis conditions, and improve pyrolysis efficiency and product purity. Next, the optimal pyrolysis plan is adjusted in combination with the target particle characteristic parameters of the waste particles. By comparing the particle characteristic parameters, the adjustment coefficient is obtained, and the pyrolysis parameters are precisely adjusted to make the pyrolysis plan more suitable for the characteristics of the actual waste particles, further improving the pyrolysis effect and product quality. After pyrolysis treatment, the target element is fully dissolved in the solution through acid leaching operation, and the purified product filtrate is measured and purified for the target element using an advanced inductively coupled plasma optical emission spectrometer to precisely analyze and control the composition and purity of the product, ensuring the high quality of the final product. Finally, the leaching residue is harmlessly treated, and various methods such as physical, chemical, and biological methods are used to reduce its harmfulness and environmental risks, achieving the harmless goal of waste treatment. Generally speaking, the embodiments of the present application improve the purification efficiency of iron phosphate waste, increase the product purity, reduce the environmental pollution risk, and promote the development of iron phosphate waste purification technology towards the direction of green, efficient, and precise.

[0090] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A green oxidation and purification method for iron phosphate waste, characterized in that Including: Processing the iron phosphate waste according to a pretreatment strategy to obtain waste particles; Obtaining a pyrolysis database and performing pyrolysis optimization analysis on the pyrolysis database to obtain an optimal pyrolysis plan; Adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles to obtain a target pyrolysis plan; Performing pyrolysis treatment on the waste particles according to the target pyrolysis plan to obtain a pyrolysis product, and performing acid leaching to obtain a product filtrate; Activating an inductively coupled plasma optical emission spectrometer to determine and purify target elements in the purified product filtrate; Obtaining a pyrolysis database and performing pyrolysis optimization analysis on the pyrolysis database to obtain an optimal pyrolysis plan, including: Extracting a first pyrolysis record from the pyrolysis database; Performing multi-dimensional evaluation and analysis on the first pyrolysis product in the first pyrolysis record to obtain a first pyrolysis completeness index; If the first pyrolysis completeness index reaches a predetermined index threshold, extracting the first pyrolysis parameters in the first pyrolysis record; Forming the optimal pyrolysis plan based on the first pyrolysis parameters; Performing multi-dimensional evaluation and analysis on the first pyrolysis product in the first pyrolysis record to obtain a first pyrolysis completeness index, including: Activating the inductively coupled plasma optical emission spectrometer to perform determination and analysis of the target elements on the first pyrolysis product to obtain a first element content; Activating a gas chromatograph to perform determination and analysis of the pyrolysis gas in the first pyrolysis product to obtain a first gas content; Introducing a pyrolysis evaluation function to perform evaluation and analysis on the first element content and the first gas content to obtain the first pyrolysis completeness index; The formula of the pyrolysis evaluation function is: ； Among them, represents the first thorough pyrolysis index, represents the measured content of the th element in the first element content, and the first element content includes the first lithium element content, the first phosphorus element content, and the first iron element content, represents the content of the th element in the waste particle, represents the weight coefficient of the first gas content, represents the measured value of the first gas content, represents the estimated volume of gas that can potentially be generated in the waste particle, represents the loss coefficient of the measured value of the first gas content.

2. The green oxidation and purification method of iron phosphate waste according to claim 1, wherein, The pretreatment strategy refers to the strategy of crushing, screening, and cleaning the iron phosphate waste.

3. The green oxidation purification method of iron phosphate waste according to claim 1, wherein, Adjusting the optimal pyrolysis plan in combination with the target particle characteristic parameters of the waste particles to obtain a target pyrolysis plan, including: Extracting the first waste particles from the first pyrolysis record and obtaining the first particle characteristic parameters of the first waste particles; Comparing the target particle characteristic parameters with the first particle characteristic parameters to obtain a first particle deviation; Using the first particle deviation as an adjustment coefficient to adjust the optimal pyrolysis plan to obtain the target pyrolysis plan.

4. The green oxidation and purification method of iron phosphate waste according to claim 3, characterized in that Obtaining predetermined particle characteristics, where the predetermined particle characteristics are used for characteristic collection of the first waste particles and the waste particles, and the predetermined particle characteristics at least include average particle size, average density, particle quantity, and particle shape.

5. The green oxidation purification method for iron phosphate waste as claimed in claim 3, characterized in that, Using the first particle deviation as an adjustment coefficient to adjust the optimal pyrolysis plan to obtain the target pyrolysis plan, including: Reading predetermined pyrolysis characteristics and extracting the first pyrolysis characteristics from the predetermined pyrolysis characteristics; Matching the first parameter corresponding to the first pyrolysis characteristic in the optimal pyrolysis plan; Adjusting the first parameter according to the adjustment coefficient to obtain a first adjusted parameter; Forming the target pyrolysis plan based on the first adjusted parameter.

6. The green oxidation and purification method of iron phosphate waste according to claim 1, characterized in that, After pyrolyzing the waste particles according to the target pyrolysis plan to obtain a pyrolysis product and subjecting it to acid leaching to obtain a product filtrate, it further includes: obtaining a leaching residue and performing harmless treatment on the leaching residue, where the leaching residue refers to the product residue obtained by subjecting the pyrolysis product to acid leaching treatment.

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