Metal extraction process and system from mixed solutions

Abstract

This invention provides a method and system for metal extraction from mixed solutions, relating to the field of metal extraction and separation technology. The method includes: acquiring initial component state information of the multi-metal mixture to be separated; calculating the coordination bond dissociation energy between each metal ion and the extractant based on the initial component state information, and constructing competitive extraction response characteristics; establishing the extraction rate evolution trajectory of each metal ion during pH changes, and constructing a separation window by identifying the intersection points of the evolution trajectories; determining the pH control target value and addition sequence for each extraction batch according to the separation window; determining the main extractant and its dosage based on the ligand field stabilization energy calculation principle; and performing batch extraction operations sequentially according to the addition sequence. This invention, by constructing competitive extraction response characteristics and separation windows, achieves precise pH control and extractant selection, improving the efficiency and purity of metal separation from multi-metal mixtures.

Description

Technical Field

[0001] This invention relates to the field of metal extraction and separation technology, and in particular to a method and system for metal extraction from mixed solutions. Background Technology

[0002] With the acceleration of industrialization and the widespread use of electronic products, large quantities of mixed solutions containing multiple valuable metals are generated, such as leachate from electronic waste, metallurgical wastewater, and electroplating wastewater. These mixed solutions often contain multiple metal ions, including copper, nickel, cobalt, zinc, and iron, which have both resource recovery value and environmental pollution risks. Traditional metal separation methods include chemical precipitation, electrolysis, ion exchange, and solvent extraction. Among these, solvent extraction has become the mainstream technology for separating multi-metal mixed solutions due to its advantages such as large processing capacity, high separation efficiency, and low energy consumption.

[0003] Currently, the extraction and separation of multi-metal mixed solutions typically employs experience-driven methods for process design. This approach has significant limitations when dealing with complex multi-metal systems. In such systems, each metal ion competes with the extractant for coordination, rendering extraction parameters obtained in single-metal systems ineffective. Traditional methods often focus only on the extraction behavior of the target metal itself, neglecting the interference effects of other coexisting metal ions. This makes it impossible to accurately predict the actual extraction rates of each metal in the multi-metal system, resulting in unsatisfactory separation effects, low metal recovery rates, and difficulty in guaranteeing product purity. Summary of the Invention

[0004] The present invention provides a method and system for metal extraction from a mixed solution, which can solve the problems in the prior art.

[0005] A first aspect of the present invention provides a method for metal extraction from a mixed solution, comprising: Obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; Based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed. Based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH change is established, and a metal ion separation window is constructed by identifying the intersection points between the evolution trajectories. Based on the extraction rate evolution trajectory function of the separation window, determine the pH control target value for each extraction batch, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. Based on the principle of ligand field stabilization energy calculation, the field stabilization energy difference between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the main extractant. The dosage of the main extractant is then calculated based on the target metal ion concentration. According to the addition sequence of each extraction batch and the corresponding amount of main extractant, the multi-metal mixture is subjected to batch extraction operations in sequence to obtain the extracted multi-metal mixture.

[0006] Based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed, including: Based on the initial component state information, the type and concentration values ​​of each metal ion are extracted to obtain the corresponding ion radius and valence electron configuration. According to the ion radius, the bond length distance between each metal ion and the extractant ligand atom is calculated. According to the valence electron configuration, the coordination field splitting energy of each metal ion is calculated. The bond length distance and the coordination field splitting energy are input into the orbital hybridization calculation model to obtain the orbital overlap integral when each metal ion forms a coordination bond with the extractant, and the coordination bond dissociation energy between each metal ion and the extractant is calculated. Based on the concentration value and the coordination bond dissociation energy, the mass action law equation is substituted into the equation to establish a set of competitive equilibrium equations under the condition of coexistence of multiple metal ions. The competitive equilibrium equations are then solved to obtain the coordination occupancy rate of each metal ion with the extractant under different pH conditions. Based on the coordination occupancy rate, the distribution ratio function of each metal ion from the aqueous phase to the organic phase is calculated. The distribution ratio function is differentiated with respect to pH to obtain the extraction rate pH sensitivity coefficient of each metal ion, thereby generating competitive extraction response characteristics.

[0007] Based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH changes is established. A metal ion separation window is constructed by identifying the intersection points between these trajectories, including: Based on the competitive extraction response characteristics, a first-order derivative function of the extraction rate of each metal ion with respect to pH is constructed, and a pH variation range is set. A pH sampling sequence is established within the pH variation range. Integrating the first derivative function yields the extraction rate evolution trajectory function of each metal ion. Extracting the extraction rate evolution trajectory function of any two metal ions, a difference function of the extraction rates of the two metal ions is established. The second derivative of the extraction rate difference function is obtained to obtain the extraction rate difference curvature function. The zero point of the extraction rate difference function is solved to obtain the pH coordinates of the intersection point. The pH coordinates of the intersection point are substituted into the extraction rate difference curvature function to obtain the curvature value of the intersection point, and the separation sensitivity index is calculated. Cross points where the sensitivity index exceeds a set threshold are screened and sorted in ascending order to obtain an effective pH boundary point sequence. The pH range is divided into multiple pH intervals. The metal ions with the highest extraction rate in each pH interval are marked as target metal ions and correlated to construct a metal ion separation window.

[0008] Based on the extraction rate evolution trajectory function of the separation window, the target pH value for each extraction batch is determined, the pH control path for each extraction batch is calculated, and the dosing sequence is determined according to the separation purity requirements of each batch, including: Based on the metal ion separation window, the extraction rate evolution trajectory function of the corresponding target separated metal ion is extracted, and its second derivative is calculated to obtain the extraction rate acceleration function and identify the inflection point position, thereby obtaining the pH control target value for this extraction batch. Based on the pH control target value, the first derivative of the extraction rate difference between the target separated metal ions and non-target metal ions with respect to pH is calculated to obtain the separation selectivity gradient function. The pH control step sequence is calculated, and the pH control step sequence is accumulated and summed to generate a segmented pH control path from the current pH state to the target pH value. The extraction rate evolution trajectory function of the non-target metal ions is integrated along the pH control path to obtain the cumulative co-extraction amount of the non-target metal ions. The impurity introduction coefficient is calculated, and when it exceeds the impurity threshold, a constant pH period is inserted into the pH control path. The operation cycle of each extraction batch is obtained by summing the pH control path duration and the constant pH period duration. The operation cycles are then sequentially accumulated to determine the dosing sequence of each extraction batch.

[0009] Based on the principle of ligand field stabilization energy calculation, the field stabilization energy difference between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the master extractant. The dosage of the master extractant is then calculated based on the target metal ion concentration, including: Extract the d orbitals, eg electron count, and t2g electron count of the target metal ions in each extraction batch, and calculate the difference in count. Based on the ligand field strength order of each candidate extractant, calculate the energy level splitting distance between the eg and t2g orbitals, and multiply it by the aforementioned difference in count to obtain the ligand field stabilization energy induced by each candidate extractant for the target metal ion. The electron spin multiplicity of the complexes formed by the target metal ions and each candidate extractant is extracted, the electron pairing repulsion energy is calculated, and the net coordination stabilization energy is calculated by combining the ligand field stabilization energy. The candidate extractant with the largest value is selected as the main extractant. For each extraction batch, the required amount of extractant for a single batch is obtained based on the concentration value and coordination stoichiometry of the target metal ion. The extraction rate data of the previous extraction batch is extracted, the concentration of residual metal ions that were not extracted in the previous batch is calculated, and the amount of extractant consumed in the cross-batch is obtained by combining the coordination stoichiometry of the main extractant in the current batch. The dosage of the main extractant is then calculated.

[0010] According to the addition sequence and corresponding main extractant dosage of each extraction batch, batch extraction operations are sequentially performed on the multi-metal mixture to obtain multiple metals after extraction, including: Based on the addition sequence and corresponding main extractant dosage of each extraction batch, during the pH dynamic control stage, the pH of the multi-metal mixture is adjusted stepwise according to the pH control path. The deviation between the current actual pH value and the target value is monitored. When the deviation exceeds the set deviation threshold, the subsequent pH control step size is corrected. Once the target pH value is reached, the process enters a constant pH settling stage. The pH value of the multi-metal mixture is stabilized at the target pH value. The main extractant is added, and the concentration change rate of the target metal ions in the organic phase is monitored. The organic phase and the aqueous phase are separated, and the target metal ions are recovered from the organic phase. Extract the types and concentration distribution of residual metal ions in the aqueous phase, update the component state information of the multi-metal mixture, repeat the extraction operation until all extraction batches are completed, and obtain the extracted multiple metals.

[0011] A second aspect of the present invention provides a system for metal extraction from a mixed solution, comprising: The first unit is used to obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; The second unit is used to analyze the competitive adsorption relationship between each metal ion and the extractant based on the initial component state information, calculate the corresponding coordination bond dissociation energy, and construct the competitive extraction response characteristics of each metal ion. The third unit is used to establish the extraction rate evolution trajectory of each metal ion during pH change based on the competitive extraction response characteristics, and to construct a metal ion separation window by identifying the intersection points between the evolution trajectories. The fourth unit is used to determine the pH control target value for each extraction batch based on the extraction rate evolution trajectory function of the separation window, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. The fifth unit is used to calculate the difference in field stabilization energy between the target metal ion and the candidate extractant when they form a complex based on the ligand field stabilization energy calculation principle, determine the main extractant, and calculate the dosage of the main extractant based on the target metal ion concentration. The sixth unit is used to sequentially perform batch extraction operations on the multi-metal mixture according to the addition sequence of each extraction batch and the corresponding amount of main extractant, so as to obtain the extracted multi-metal mixture.

[0012] A third aspect of the embodiments of the present invention, An electronic device is provided, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0013] Fourth aspect of the present invention, A computer-readable storage medium is provided, having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0014] The beneficial effects of this application are as follows: This invention establishes the extraction rate evolution trajectory of metal ions during pH changes and identifies the intersection points between these trajectories to construct a separation window. This enables precise positioning of the optimal separation conditions for different metal ions, allowing each metal ion to be selectively extracted under its own optimal pH conditions. This significantly improves the selectivity and efficiency of separation and reduces mutual interference between metal ions.

[0015] This invention determines the main extractant and its dosage based on the principle of ligand field stabilization energy calculation, and performs batch extraction operations sequentially according to the scientifically calculated addition sequence. This achieves precise configuration and use of the extractant, which not only improves the extraction rate and product purity of the target metal, but also effectively reduces the waste and cost of the extractant, making the entire extraction and separation process more economical, efficient and easy to industrialize. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a metal extraction method from a mixed solution according to an embodiment of the present invention; Figure 2 A schematic diagram of the process for generating the competitive extraction response characteristics of various metal ions. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0019] Figure 1 This is a schematic flowchart of a metal extraction method from a mixed solution according to an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes: Obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; Based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed. Based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH change is established, and a metal ion separation window is constructed by identifying the intersection points between the evolution trajectories. Based on the extraction rate evolution trajectory function of the separation window, determine the pH control target value for each extraction batch, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. Based on the principle of ligand field stabilization energy calculation, the field stabilization energy difference between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the main extractant. The dosage of the main extractant is then calculated based on the target metal ion concentration. According to the addition sequence of each extraction batch and the corresponding amount of main extractant, the multi-metal mixture is subjected to batch extraction operations in sequence to obtain the extracted multi-metal mixture.

[0020] Figure 2 This is a schematic diagram of a method for generating competitive extraction response characteristics of various metal ions. In one optional embodiment, based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed, including: Based on the initial component state information, the type and concentration values ​​of each metal ion are extracted to obtain the corresponding ion radius and valence electron configuration. According to the ion radius, the bond length distance between each metal ion and the extractant ligand atom is calculated. According to the valence electron configuration, the coordination field splitting energy of each metal ion is calculated. The bond length distance and the coordination field splitting energy are input into the orbital hybridization calculation model to obtain the orbital overlap integral when each metal ion forms a coordination bond with the extractant, and the coordination bond dissociation energy between each metal ion and the extractant is calculated. Based on the concentration value and the coordination bond dissociation energy, the mass action law equation is substituted into the equation to establish a set of competitive equilibrium equations under the condition of coexistence of multiple metal ions. The competitive equilibrium equations are then solved to obtain the coordination occupancy rate of each metal ion with the extractant under different pH conditions. Based on the coordination occupancy rate, the distribution ratio function of each metal ion from the aqueous phase to the organic phase is calculated. The distribution ratio function is differentiated with respect to pH to obtain the extraction rate pH sensitivity coefficient of each metal ion, thereby generating competitive extraction response characteristics.

[0021] In the metal ion competitive extraction process, after obtaining the initial component state information of the solution to be treated, it is necessary to extract the types of metal ions contained therein and their corresponding concentration values. When the solution contains Cu... 2+ Ni 2+ and Co 2+ At that time, Cu 2+ The concentration is 350 mg / L, Ni 2+ The concentration is 280 mg / L, Co 2+ The concentration is 420 mg / L. Based on the periodic table and ion structure database, Cu was found... 2+ The ionic radius of Ni is 0.073 nm. 2+ The ionic radius of Co is 0.069 nm. 2+ The ionic radius is 0.065 nm. Simultaneously, the valence electron configurations of these metal ions, Cu, were obtained. 2+ The valence electron configuration of Ni is d9. 2+ For d8, Co 2+ It is d7.

[0022] When P507 extractant is selected as the ligand, its ligand atom is O, and the covalent radius of the O atom is 0.066 nm. The bond length distance between each metal ion and the extractant ligand atom is calculated, and the sum of the ionic radius and the covalent radius of the ligand atom is used as the theoretical bond length. Cu 2+ The bond length distance with the O atom is 0.139 nm, Ni 2+ The bond length distance with the O atom is 0.135 nm, Co 2+The bond length distance with the O atom is 0.131 nm. The calculation of the ligand field splitting energy is based on crystal field theory. Under the influence of the ligand field, the d orbitals undergo energy level splitting, and the degree of splitting is related to the field strength of the ligand and the valence electron configuration of the metal ion. Cu 2+ The ligand field splitting energy is 12500 cm⁻¹ -1 Ni 2+ The ligand field splitting energy is 8500 cm⁻¹ -1 Co 2+ The ligand field splitting energy is 9200 cm⁻¹. -1 .

[0023] The calculated bond lengths and ligand splitting energies are input into the orbital hybridization calculation model. This model, based on molecular orbital theory, considers the interaction between the d orbitals of the metal ion and the p orbitals of the ligand atoms. Input bond lengths of 0.139 nm, 0.135 nm, and 0.131 nm, along with the corresponding ligand splitting energies, are used. The model calculates the spatial overlap of the orbital wavefunctions and outputs the orbital overlap integral. (Cu) 2+ The orbital overlap integral when Ni forms a coordinate bond with the extractant is 0.42. 2+ The corresponding value is 0.38, Co 2+ The corresponding value is 0.35. A larger orbital overlap integral indicates stronger bonding ability. The coordinate bond dissociation energy is determined by the combined effect of the orbital overlap integral and the ligand field splitting energy. Cu 2+ The dissociation energy of the coordination bond between Ni and the extractant is 285 kJ / mol. 2+ The corresponding coordinate bond dissociation energy is 242 kJ / mol, Co 2+ The corresponding coordinate bond dissociation energy is 218 kJ / mol.

[0024] A set of competitive equilibrium equations under the condition of coexistence of multiple metal ions was established. The concentrations of each metal ion and the coordinate bond dissociation energies were substituted into the law of mass action equations. Cu 2+ A concentration of 350 mg / L corresponds to a molar concentration of 5.5 mmol / L, Ni 2+ A concentration of 280 mg / L corresponds to a molar concentration of 4.8 mmol / L, Co 2+ A concentration of 420 mg / L corresponds to a molar concentration of 7.1 mmol / L. The initial concentration of the extractant in the organic phase was set at 0.5 mol / L. The coordination bond dissociation energy determines the stability constant of the complex formed between the metal ions and the extractant. Cu 2+ The logarithm of the stability constant of Ni is 14.2. 2+ The logarithm of the stability constant is 12.1, Co 2+The logarithmic stability constant is 10.8. Within a pH range of 2.0 to 6.0, a system of equations was established involving the competitive coordination of three metal ions. The total amount of extractant in the solution remained constant, and the sum of the coordinated extractant dose and the free extractant dose equaled the initial total. The extractant dose consumed by each metal ion was calculated using the ion's concentration, stability constant, and free extractant concentration.

[0025] An iterative numerical method was used to solve the competing equilibrium equations. With a pH of 3.0 and an initial assumption of a free extractant concentration of 0.4 mol / L, the concentrations of complexes formed between each metal ion and the extractant were calculated. (Cu) 2+ The concentration of the formed complex was 4.8 mmol / L, Ni 2+ The concentration of the formed complex was 3.2 mmol / L, Co 2+ The concentration of the formed complex was 2.1 mmol / L. The concentrations of each complex were converted to the amount of extractant consumed, and a material balance check was performed against the initial total extractant amount. The free extractant concentration was adjusted until the deviation was less than 0.001 mol / L. Through similar calculations, the coordination occupancy rates of each metal ion at pH values ​​of 2.5, 3.5, 4.0, 4.5, and 5.0 were obtained, including Cu. 2+ The coordination occupancy rate at pH 3.0 was 87.3%, Ni 2+ It was 66.7%, Co 2+ It is 29.6%.

[0026] The distribution ratio function of each metal ion from the aqueous phase to the organic phase is calculated using the coordination occupancy rate. The distribution ratio is defined as the ratio of the metal ion concentration in the organic phase to the metal ion concentration in the aqueous phase. Cu 2+ The partition ratio at pH 3.0 was 6.88, Ni 2+ The allocation ratio is 2.00, Co 2+ The distribution ratio was 0.42. As the pH increased from 2.5 to 5.0, Cu... 2+ The allocation ratio increased from 3.25 to 28.6, Ni 2+ The allocation ratio increased from 0.85 to 9.2, Co 2+ The distribution ratio increased from 0.12 to 2.4. The distribution ratio function was differentiated with respect to pH, and the rate of change of the distribution ratio between adjacent pH points was calculated using a numerical differentiation method. 2+ The extraction efficiency pH sensitivity coefficient is 4.52 around pH 3.0, Ni 2+ The sensitivity coefficient is 1.86, Co 2+The sensitivity coefficient is 0.63. The sensitivity coefficient reflects the response amplitude of the extraction rate when the pH value changes by a unit value. The larger the value, the more sensitive the extraction behavior of the metal ion is to the change in pH value. The generated competitive extraction response characteristics include the coordination occupancy rate curve, partition ratio curve and sensitivity coefficient distribution spectrum of each metal ion under different pH conditions, which are used to guide the optimization and control of subsequent extraction process parameters.

[0027] In one optional implementation, based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH changes is established, and a metal ion separation window is constructed by identifying the intersection points between the evolution trajectories, including: Based on the competitive extraction response characteristics, a first-order derivative function of the extraction rate of each metal ion with respect to pH is constructed, and a pH variation range is set. A pH sampling sequence is established within the pH variation range. Integrating the first derivative function yields the extraction rate evolution trajectory function of each metal ion. Extracting the extraction rate evolution trajectory function of any two metal ions, a difference function of the extraction rates of the two metal ions is established. The second derivative of the extraction rate difference function is obtained to obtain the extraction rate difference curvature function. The zero point of the extraction rate difference function is solved to obtain the pH coordinates of the intersection point. The pH coordinates of the intersection point are substituted into the extraction rate difference curvature function to obtain the curvature value of the intersection point, and the separation sensitivity index is calculated. Cross points where the sensitivity index exceeds a set threshold are screened and sorted in ascending order to obtain an effective pH boundary point sequence. The pH range is divided into multiple pH intervals. The metal ions with the highest extraction rate in each pH interval are marked as target metal ions and correlated to construct a metal ion separation window.

[0028] In this specific embodiment, based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH change is established, and a metal ion separation window is constructed by identifying the intersection points between the evolution trajectories. Taking a mixed solution containing copper, nickel, and cobalt ions as an example, the initial copper ion concentration of the solution to be separated is 150 mg / L, the nickel ion concentration is 120 mg / L, the cobalt ion concentration is 100 mg / L, the extractant is di-(2-ethylhexyl)phosphoric acid, and the volume ratio of the organic phase to the aqueous phase is 1:1.

[0029] Based on the acquired competitive extraction response characteristic data, a first-order derivative function of the extraction rate of each metal ion with respect to pH was constructed. For copper ions, within the pH range of 2.0 to 5.0, analysis of experimental data points revealed that the extraction rate increased from 12% to 98%. The rate of change of extraction rate between adjacent pH points was calculated using a numerical differential method, with the pH change set to 0.1 units, to obtain the extraction rate change rate corresponding to each pH point. At pH 3.2, the rate of change of copper ion extraction rate reached its peak, with each unit pH change causing approximately a 35% change in extraction rate. For nickel ions, within the pH range of 4.0 to 7.0, the extraction rate increased from 8% to 95%, with its rate of change peaking at pH 5.5, resulting in approximately a 28% change in extraction rate per unit pH change. For cobalt ions, within the pH range of 5.0 to 8.0, the extraction rate increased from 5% to 92%, with its rate of change peaking at pH 6.3, resulting in approximately a 25% change in extraction rate per unit pH change.

[0030] The pH range was set to 2.0 to 8.0. A pH sampling sequence was established, using an equal-interval sampling method. The pH range was divided into steps of 0.05, resulting in 121 sampling points at values ​​from 2.00, 2.05, 2.10 to 8.00. At each sampling point, the corresponding first derivative value of the extraction rate was recorded or calculated, forming a discrete derivative dataset.

[0031] The extraction rate evolution trajectory function of each metal ion was obtained by integrating the first derivative function. The trapezoidal integral method was used to accumulate and sum the discrete first derivative data, starting with the initial extraction rate at pH 2.0 as the integration starting point. The extraction rate value at each pH point was calculated progressively. For copper ions, the extraction rate was 25% at pH 2.5, 63% at pH 3.0, 89% at pH 3.5, and 97% at pH 4.0. For nickel ions, the extraction rate was 18% at pH 4.5, 42% at pH 5.0, 68% at pH 5.5, 85% at pH 6.0, and 93% at pH 6.5. For cobalt ions, the extraction rate was 15% at pH 5.5, 38% at pH 6.0, 62% at pH 6.5, 81% at pH 7.0, and 90% at pH 7.5.

[0032] Extraction rate evolution trajectory functions of any two metal ions are extracted, and extraction rate difference functions are established. Copper ions and nickel ions are selected as the first pair of analytical objects. The difference in extraction rates between the two is calculated at each pH sampling point. At pH 4.0, the extraction rate of copper ions is 97%, the extraction rate of nickel ions is 12%, and the difference is 85%. At pH 5.0, the extraction rate of copper ions is 98%, the extraction rate of nickel ions is 42%, and the difference is 56%. At pH 6.0, the extraction rate of copper ions is 98%, the extraction rate of nickel ions is 85%, and the difference is 13%. By traversing all pH sampling points, a complete extraction rate difference data sequence is formed.

[0033] The second derivative of the extraction rate difference function is obtained to get the extraction rate difference curvature function. The second derivative is calculated using the central difference method. For the curvature value at pH point i, it is calculated by the rate of change of the difference between two adjacent points before and after this point. Taking the difference sequence of copper ions and nickel ions as an example, in the pH range of 4.8 to 5.2, the difference decreases from 62% to 48% and then to 34%. The calculated curvature value in this range is negative, indicating that the difference curve bends downward. Near pH 5.5, the absolute value of the curvature reaches a local maximum, with a value of about 18, indicating that the difference change is most drastic at this position.

[0034] Zero-point solving was performed on the extraction rate difference function to obtain the pH coordinates of the crossover point. Linear interpolation was then used to locate the position of sign change in the difference sequence. For copper and nickel ions, although their extraction rate curves differed in shape, the extraction rate of copper ions remained higher than that of nickel ions throughout the entire pH range, therefore no zero-point crossover occurred. For nickel and cobalt ions, the difference changed from 3% to -2% at pH 6.8. Linear interpolation yielded the precise pH coordinates of the crossover point at 6.82, where the extraction rates of both nickel and cobalt ions were 89%.

[0035] Substituting the pH coordinates of the intersection point into the curvature function of the extraction rate difference, the curvature value of the intersection point is obtained. For the intersection point of nickel ions and cobalt ions at pH 6.82, the second derivative value corresponding to this position is queried. The curvature value is calculated as -12 by the difference data of the three adjacent points. The larger the absolute value of the curvature, the steeper the change in the separation degree of the two extraction rate curves near the intersection point, the narrower the pH control window of the separation operation, and the higher the required operation precision.

[0036] The separation sensitivity index was calculated. Separation sensitivity is defined as the product of the absolute value of curvature at the intersection point and the sum of the extraction rates of the two metal ions. For the intersection point of nickel and cobalt ions at pH 6.82, the absolute value of curvature is 12, and the sum of the extraction rates of the two ions is 178%. The separation sensitivity index was calculated to be 2136. This index comprehensively reflects the sharpness of the intersection point and the extraction efficiency. The larger the value, the more effective the intersection point is as a separation boundary.

[0037] Crossover points where the separation sensitivity index exceeded a set threshold were screened. Based on the actual pH control accuracy and desired separation effect, the separation sensitivity threshold was set to 1500. Crossover points for all metal ion pairs were evaluated one by one. The crossover point between nickel and cobalt ions at pH 6.82 had a sensitivity of 2136, exceeding the threshold and was retained. For copper and nickel ions, although there was no true zero-point crossover, the inflection point where the extraction rate difference reached its minimum could be identified as a quasi-crossover point. At pH 5.1, the minimum difference was 30 percentage points, with an absolute curvature of 8 at this position, resulting in a separation sensitivity of 1520, which also exceeded the threshold and was retained.

[0038] The retained effective crossover points were sorted in ascending order to obtain an effective pH cutoff point sequence. After screening, two effective cutoff points were identified, arranged in ascending order of pH value as 5.1 and 6.82. These two pH values ​​divide the entire operating range into clear separation segments, further dividing the pH variation range into multiple pH intervals: the first interval is from pH 2.0 to 5.1, the second interval is from pH 5.1 to 6.82, and the third interval is from pH 6.82 to 8.0. In the first interval, the average extraction rate of copper ions was 92%, nickel ions 18%, and cobalt ions 5%, with copper ions exhibiting the highest extraction rate and thus designated as the target metal ion for separation. In the second interval, the average extraction rate of copper ions was 98%, nickel ions 78%, and cobalt ions 25%, with copper ions still maintaining the highest extraction rate. In the third interval, the average extraction rate of copper ions was 98%, nickel ions 94%, and cobalt ions 88%, with all three ions achieving high extraction rates, but copper ions still showing the highest extraction rate.

[0039] Each pH range is associated with a target metal ion to construct a metal ion separation window. The first separation window, corresponding to a pH range of 2.0 to 5.1, specifies copper ions as the target for recovery. This window enables selective extraction of copper ions, with a separation coefficient greater than 50 compared to nickel and cobalt ions. The second separation window, corresponding to a pH range of 5.1 to 6.82, enables co-extraction of copper and nickel ions and separation from cobalt ions, with a total extraction rate of over 85% for copper and nickel ions and a cobalt ion extraction rate of less than 40%. The third separation window, corresponding to a pH range of 6.82 to 8.0, is suitable for the full recovery of all three metal ions, with a total extraction rate exceeding 93%. Through this separation window system, operators can select an appropriate pH control range according to the separation target to achieve the tiered separation or combined recovery of different metal ions.

[0040] In one optional implementation, the target pH value for each extraction batch is determined based on the extraction rate evolution trajectory function of the separation window, the pH control path for each extraction batch is calculated, and the dosing sequence is determined according to the separation purity requirements of each batch, including: Based on the metal ion separation window, the extraction rate evolution trajectory function of the corresponding target separated metal ion is extracted, and its second derivative is calculated to obtain the extraction rate acceleration function and identify the inflection point position, thereby obtaining the pH control target value for this extraction batch. Based on the pH control target value, the first derivative of the extraction rate difference between the target separated metal ions and non-target metal ions with respect to pH is calculated to obtain the separation selectivity gradient function. The pH control step sequence is calculated, and the pH control step sequence is accumulated and summed to generate a segmented pH control path from the current pH state to the target pH value. The extraction rate evolution trajectory function of the non-target metal ions is integrated along the pH control path to obtain the cumulative co-extraction amount of the non-target metal ions. The impurity introduction coefficient is calculated, and when it exceeds the impurity threshold, a constant pH period is inserted into the pH control path. The operation cycle of each extraction batch is obtained by summing the pH control path duration and the constant pH period duration. The operation cycles are then sequentially accumulated to determine the dosing sequence of each extraction batch.

[0041] For multi-metal ion extraction systems, a copper-nickel-cobalt ternary system is used as an example. When the concentration of copper ions in the feed solution is 15 g / L, the concentration of nickel ions is 8 g / L, and the concentration of cobalt ions is 3 g / L, the target pH value for each batch is determined by calculating the second derivative of the extraction rate evolution trajectory function. For the extraction rate evolution trajectory of copper ions, the extraction rate increases from 5% to 99.5% within the pH range of 2.0 to 5.0. The extraction rate acceleration function is obtained by calculating the second derivative of this trajectory, which reflects the changing trend of the extraction rate growth rate. Through numerical analysis of the acceleration function, the inflection point where the acceleration changes from positive to negative is identified at pH 3.2, at which point the extraction rate is approximately 50%. This inflection point is the target pH value for the copper ion extraction batch.

[0042] After determining the target pH value, the control path from the current operating pH of 2.8 to the target pH of 3.2 is calculated. For the separation of copper and nickel ions, the first derivative of the difference in extraction rates between the two ions with respect to pH is calculated, yielding the separation selectivity gradient function. This gradient function shows that within the pH range of 2.8 to 3.0, the pH derivative of the copper-nickel extraction rate difference corresponds to a 42% change in extraction rate difference per unit pH change. Within the pH range of 3.0 to 3.2, this derivative decreases to a 28% change in extraction rate difference per unit pH change. Based on the characteristics of the gradient function, a smaller pH control step size is used in the range with a larger gradient: a step size of 0.05 pH units in the pH range of 2.8 to 3.0, and a step size of 0.08 pH units in the pH range of 3.0 to 3.2, generating a pH control step size sequence of 0.05, 0.05, 0.05, 0.05, 0.08, 0.08, 0.08. The step length sequence was cumulatively summed to obtain the control points of the segmented pH regulation path as 2.85, 2.90, 2.95, 3.00, 3.08, 3.16, and 3.24, forming a complete regulation path from the current pH state to the target pH value.

[0043] Along the generated pH control path, the evolution trajectory of the extraction rate of nickel ions as a non-target metal ion was integrally calculated. At pH 2.8, the nickel ion extraction rate was 0.8%. The extraction rates at various control points along the path were 1.2%, 2.1%, 3.6%, 6.2%, 10.5%, 17.8%, and 29.3%, respectively. A trapezoidal integral method was used to integrate each path segment. The integral value for the first segment, from pH 2.8 to 2.85, was 0.05, and for the second segment, it was 0.08. These values ​​were accumulated to obtain a cumulative co-extraction amount of nickel ions of 0.82 percentage points. The impurity introduction coefficient was set as the ratio of the cumulative co-extraction amount to the increase in the target ion extraction rate. The copper ion extraction rate increased from 38% to 54% along this path, an increase of 16%, therefore the impurity introduction coefficient was 0.82 / 16 = 0.051. When the set impurity threshold was 0.045, the calculated impurity introduction coefficient of 0.051 exceeded this threshold, requiring the insertion of a constant pH period into the pH control path.

[0044] A constant pH period was inserted at pH 3.0. During this period, the pH value was kept constant, and only the extractant was continuously added. During the constant pH period, the copper ion extraction rate continued to increase from 45.2% to 49.8%, while the nickel ion extraction rate only slowly increased from 6.2% to 6.9%. By operating at constant pH, copper ions were preferentially extracted kinetically, reducing the co-extraction rate of nickel ions. The duration of the constant pH period was set to 18 minutes. After this period, pH control was restarted, and the pH value was adjusted from 3.0 to 3.2 according to the original path.

[0045] For the copper ion extraction batch, the pH adjustment path duration was calculated based on the adjustment rate of each segment. The dynamic adjustment phase from pH 2.8 to 3.0 took 22 minutes, the constant pH period was 18 minutes, and the subsequent adjustment phase from pH 3.0 to 3.2 took 15 minutes, for a total operation cycle of 55 minutes. For the nickel ion extraction batch, the target pH value was determined to be 4.8 using the same method, with an operation cycle of 48 minutes. For the cobalt ion extraction batch, the target pH value was determined to be 6.2, with an operation cycle of 41 minutes. The operation cycles of each batch were sequentially accumulated: the addition sequence for the copper ion batch started at 0 minutes and ended at 55 minutes; for the nickel ion batch, the addition sequence started at 55 minutes and ended at 103 minutes; and for the cobalt ion batch, the addition sequence started at 103 minutes and ended at 144 minutes. This sequential arrangement enables the batch-by-batch extraction and separation of the three metal ions, with automatic switching between batches achieved through precise time control. The entire extraction process completes the separation and extraction of the three metal ions within 144 minutes.

[0046] In one optional implementation, based on the principle of ligand field stabilization energy calculation, the difference in field stabilization energy between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the main extractant. The dosage of the main extractant is then calculated based on the target metal ion concentration, including: Extract the d orbitals, eg electron count, and t2g electron count of the target metal ions in each extraction batch, and calculate the difference in count. Based on the ligand field strength order of each candidate extractant, calculate the energy level splitting distance between the eg and t2g orbitals, and multiply it by the aforementioned difference in count to obtain the ligand field stabilization energy induced by each candidate extractant for the target metal ion. The electron spin multiplicity of the complexes formed by the target metal ions and each candidate extractant is extracted, the electron pairing repulsion energy is calculated, and the net coordination stabilization energy is calculated by combining the ligand field stabilization energy. The candidate extractant with the largest value is selected as the main extractant. For each extraction batch, the required amount of extractant for a single batch is obtained based on the concentration value and coordination stoichiometry of the target metal ion. The extraction rate data of the previous extraction batch is extracted, the concentration of residual metal ions that were not extracted in the previous batch is calculated, and the amount of extractant consumed in the cross-batch is obtained by combining the coordination stoichiometry of the main extractant in the current batch. The dosage of the main extractant is then calculated.

[0047] In this specific embodiment, electronic configuration analysis of the target metal ions in the solution to be treated is required, using copper ions (Cu) as an example. 2+For example, this ion has a d9 electronic configuration. In the octahedral ligand field, the electron distribution is as follows: 6 electrons are filled in the t2g orbital and 3 electrons are filled in the eg orbital. Statistical analysis shows that the number of t2g electrons is 6 and the number of eg electrons is 3. The difference between the two is calculated to be 3-6=-3. This difference is used for the subsequent quantitative assessment of the ligand field stabilization energy.

[0048] When performing quantitative analysis of the ligand field strength of candidate extractants, spectrochemical sequences were used as the criterion. When the candidate extractant was H2O, its ligand field splitting energy was taken as 10000 cm⁻¹. -1 When the candidate extractant is an NH3-type ligand, its ligand field splitting energy is 10500 cm⁻¹. -1 When the candidate extractant is an ethylenediamine ligand, its ligand field splitting energy is 11000 cm⁻¹. -1 When the candidate extractant is an o-phenanthroline ligand, its ligand field splitting energy is 13000 cm⁻¹. -1 Multiplying the ligand field splitting energy of each candidate extractant by the absolute value of the aforementioned difference in electron numbers yields the ligand field stabilization energy induced by each extractant for the target metal ion. For example, the ligand field stabilization energy of o-phenanthroline extractants is 13000 cm⁻¹. -1 ×3=39000cm -1 The stabilization energy contribution.

[0049] When calculating electron pairing repulsion energies, it is necessary to determine the electron spin state of the target metal ion after forming complexes with each candidate extractant. For Cu 2+ The complex formed with 1,000 phenanthroline exhibits a low-spin state due to its strong-field ligand nature. The d orbitals contain three pairs of paired electrons, with each pair having a pairing repulsion energy of 15,000 cm⁻¹. -1 The total pairing repulsion energy of the three pairs of paired electrons is 45000 cm⁻¹. -1 And Cu 2+ In the free state, it has only one pair of paired electrons, and the pairing repulsion energy is 15000 cm⁻¹. -1 The additional pairing repulsion energy of the complex is 45000 cm⁻¹. -1 -15000cm -1 =30000cm -1 .

[0050] The net coordination stabilization energy is obtained by subtracting the additional pairing repulsion energy from the ligand field stabilization energy for Cu. 2+ The net coordination stabilization energy of the complex system with o-phenanthroline is 39000 cm⁻¹. -1 -30000cm -1 =9000cm -1Compared to other candidate extractants, H2O has a net coordination stabilization energy of 3000 cm⁻¹. -1 The net coordination stabilization energy of NH3-type extractants is 4500 cm⁻¹. -1 The net coordination stabilization energy of ethylenediamine extractants is 6500 cm⁻¹. -1 By comparing the net coordination stabilization energies of the candidate extractants, the o-phenanthroline extractant had the largest net coordination stabilization energy and was therefore selected as the main extractant for this extraction batch.

[0051] After determining the main extractant, its dosage needs to be calculated. Assume that in a certain extraction batch, Cu... 2+ The initial concentration is 0.05 mol / L, and the solution volume is 1000 L. Therefore, the Cu content in this batch... 2+ The amount of substance is 50 mol. Based on the reaction of o-phenanthroline and Cu... 2+ The coordination stoichiometry is 2:1, meaning that one Cu 2+ Two 1,000 phenanthrene molecules are required for chelation coordination, and the basic requirement for a single batch of extractant is 100 mol.

[0052] In multi-batch continuous extraction processes, the residual effects of previous batches need to be considered. Let's assume the first extraction batch processed Ni. 2+ The solution had an initial concentration of 0.08 mol / L and a volume of 1000 L. The extraction rate of this batch was 85%. Calculate the residual Ni from the previous batch that was not extracted. 2+ The concentration is 0.08 mol / L × 15% = 0.012 mol / L. Residual Ni 2+ The amount of substance is 12 mol, o-phenanthroline and Ni 2+ The coordination stoichiometry is also 3:1, treating residual Ni 2+ It requires the consumption of 36 mol of o-phenanthroline.

[0053] Add the basic requirement of the single-batch extractant to the cross-batch extractant consumption to obtain the actual dosage of the main extractant. This is relevant to the current Cu... 2+ For the extraction batch, the total dosage of o-phenanthroline is 100mol + 36mol = 136mol. Considering the losses and safety factors in actual operation, a 10% redundancy is usually added to the calculated result, and the actual dosage of o-phenanthroline is determined to be 149.6mol.

[0054] When an extraction batch involves the coexistence of multiple target metal ions, it is necessary to calculate the net coordination stabilization energy of each metal ion separately. For example, if a batch contains Co... 2+ and Ni 2+ Co 2+ The concentration is 0.03 mol / L, Ni 2+The concentration is 0.04 mol / L. Co 2+ The d7 electron configuration has 5 t2g electrons and 2 eg electrons in an octahedral field, and the net coordination stabilization energy for forming a complex with o-phenanthroline is 12000 cm⁻¹. -1 Ni 2+ The net coordination stabilization energy corresponding to the d8 electron configuration is 10500 cm⁻¹. -1 Due to Co 2+ With a higher net coordination stabilization energy, o-phenanthroline for Co 2+ The selective extraction capability is stronger, and the actual dosage calculation should prioritize meeting the Co requirement. 2+ Extraction requirements.

[0055] In one optional embodiment, batch extraction is performed sequentially on the multi-metal mixture according to the addition sequence of each extraction batch and the corresponding dosage of the main extractant, to obtain the extracted multiple metals, including: Based on the addition sequence and corresponding main extractant dosage of each extraction batch, during the pH dynamic control stage, the pH of the multi-metal mixture is adjusted stepwise according to the pH control path. The deviation between the current actual pH value and the target value is monitored. When the deviation exceeds the set deviation threshold, the subsequent pH control step size is corrected. Once the target pH value is reached, the process enters a constant pH settling stage. The pH value of the multi-metal mixture is stabilized at the target pH value. The main extractant is added, and the concentration change rate of the target metal ions in the organic phase is monitored. The organic phase and the aqueous phase are separated, and the target metal ions are recovered from the organic phase. Extract the types and concentration distribution of residual metal ions in the aqueous phase, update the component state information of the multi-metal mixture, repeat the extraction operation until all extraction batches are completed, and obtain the extracted multiple metals.

[0056] In this specific embodiment, before starting the extraction operation, it is necessary to determine the dosing sequence and corresponding main extractant dosage for each extraction batch. Taking a typical industrial wastewater treatment case as an example, the volume of the multi-metal mixture to be treated is 1000L, the initial pH value is 2.3, and Cu... 2+ The concentration is 8.5 g / L, Ni 2+ The concentration was 6.2 g / L, Co 2+ The concentration is 3.8 g / L, Zn 2+ The concentration was 4.5 g / L, Fe 3+ The concentration was 2.1 g / L. According to the pre-planned extraction protocol, the target for the first batch extraction was Cu. 2+ The second batch was Fe 3+ The third batch is Co 2+ The fourth batch is Ni2+ The fifth batch is Zn 2+ .

[0057] When entering the pH dynamic adjustment stage of the first batch extraction, the pH value of the multi-metal mixture needs to be adjusted from the initial value of 2.3 to Cu. 2+ The target pH value for extraction was 2.8. The pH adjustment process was carried out in a step-by-step manner, dividing the entire pH adjustment range into multiple adjustment steps. Specifically, each adjustment step was set to 0.1 pH units, meaning the pH value was adjusted sequentially to 2.4, 2.5, 2.6, and 2.7, ultimately reaching the target value of 2.8. In each adjustment step, NaOH solution with a concentration of 3 mol / L was added to the mixture as a pH adjuster. When adjusting the pH from 2.3 to 2.4, the calculated required volume of NaOH solution was approximately 0.85 L. This was added slowly followed by thorough stirring for 5 minutes at a speed of 200 rpm.

[0058] During pH adjustment, an online pH monitoring probe was used to detect the actual pH value of the multi-metal mixture in real time. The probe collected data every 30 seconds and transmitted the data to the control system. After the first adjustment step was completed, the actual pH value was 2.42, a deviation of 0.02 pH units from the target value of 2.4. The preset deviation threshold was 0.05 pH units. Since the current deviation did not exceed this threshold, the next adjustment was continued according to the original adjustment step size. During the adjustment from 2.5 to 2.6, due to the influence of buffer substances in the mixture, the actual monitored value reached 2.67, a deviation of 0.07 pH units, exceeding the set deviation threshold. At this point, the subsequent pH adjustment step size was automatically corrected, reducing the original 0.1 pH unit adjustment step size to 0.08 pH units, and correspondingly reducing the amount of NaOH solution added from the original 0.92 L to 0.74 L to avoid pH overshoot.

[0059] After stepwise adjustments, the pH of the multi-metal mixture finally stabilized at 2.8. The entire dynamic control phase took approximately 28 minutes. After entering the constant pH settling phase, the pH constant control mode was activated, and the pH was maintained within the range of 2.8 ± 0.03 by adding trace amounts of NaOH or dilute H₂SO₄ solution. During this phase, the mixture was slowly stirred at a speed reduced to 80 rpm, and the settling time was 10 minutes, allowing the system to reach ion distribution equilibrium.

[0060] Once the pH has stabilized, begin adding the first batch of the primary extractant, targeting Cu. 2+ For extraction, the primary extractant used was a hydroxyoxime extractant with a volume concentration of 15% in kerosene, based on Cu... 2+Given an initial concentration of 8.5 g / L and an expected extraction rate of 92%, the required extractant volume was calculated to be 420 L, with an organic phase to aqueous phase volume ratio of 0.42:1. The extractant was added to the mixture in three 5-minute increments of 140 L each, with the stirring speed increased to 300 rpm to promote sufficient contact and mass transfer between the two phases. After the extractant addition was complete, vigorous stirring was maintained for 15 minutes to allow Cu to fully mature. 2+ Completely transfer to the organic phase.

[0061] During the extraction process, samples were taken every 3 minutes to analyze the Cu in the organic phase. 2+ The concentration of Cu in the organic phase during the first sampling. 2+ The initial concentration was 4.2 g / L. The concentration increased to 12.8 g / L in the second sampling, 17.6 g / L in the third, 19.5 g / L in the fourth, 20.1 g / L in the fifth, and 20.3 g / L in the sixth. The concentration change rate between adjacent samplings was calculated. When the concentration change rate from the fifth to the sixth sampling decreased to below 1%, the extraction reaction was considered to be close to equilibrium. At this point, stirring was stopped, and the mixture was allowed to stand for 20 minutes to separate into layers. Because the density of the organic phase is less than that of the aqueous phase, the organic phase aggregated in the upper layer of the container, while the aqueous phase was in the lower layer, and the interface between the two phases was clearly visible.

[0062] Gravity separation was used to separate the organic and aqueous phases. The lower aqueous phase was first discharged to a temporary storage tank via a drain valve at the bottom of the container, with the discharge flow rate controlled at 50 L / min to avoid disturbing the separation interface. After the aqueous phase was discharged, the upper organic phase was transferred to the extract treatment system. In the organic phase, Cu... 2+ It exists in the form of a copper extract and needs to be recovered through a back-extraction process. A 4 mol / L H₂SO₄ solution was used as the back-extraction agent, and the back-extraction operation was carried out at a volume ratio of organic phase to back-extraction agent of 3:1, with a stirring time of 12 min and a settling time of 15 min. The Cu in the aqueous solution after back-extraction... 2+ The concentration was enriched to 58 g / L, and after further electrolysis or chemical precipitation, Cu product with a purity of 99.2% was recovered.

[0063] After the first batch of extraction was completed, the aqueous phase in the temporary storage tank was sampled and analyzed to detect the types and concentration distribution of residual metal ions. The analysis results showed that Cu 2+ The residual concentration was 0.68 g / L, Ni 2+ The concentration was 6.15 g / L, Co 2+ The concentration is 3.75 g / L, Zn 2+ The concentration was 4.48 g / L, Fe 3+The concentration was 2.08 g / L. Based on this detection data, the component state information of the multimetallic mixture was updated, and the aqueous phase was used as the feed liquid for the second batch of extraction and re-input into the extraction system.

[0064] The target metal extracted in the second batch was Fe. 3+ The pH value needs to be adjusted from the current 2.8 to Fe. 3+ The target pH value for extraction is 3.5. The pH dynamic control procedure is repeated, adjusting in steps of 0.1 pH units, and the deviation between the actual pH value and the target value is monitored in real time. Once the pH value of 3.5 is reached, the appropriate Fe is added. 3+ The main extractant was a phosphate extractant with a volume concentration of 20% and an addition volume of 280 L. After stirring extraction, settling and phase separation, Fe was recovered from the organic phase. Analysis of the aqueous phase after extraction revealed Fe... 3+ The residual concentration decreased to 0.15 g / L, while the concentrations of other metal ions remained relatively stable. After updating the component state information, the third batch of extraction was initiated.

[0065] Following the same operating procedure, complete Co in sequence. 2+ Ni 2+ and Zn 2+ Batch extraction, Co 2+ The target pH for extraction was 5.2, the main extractant was a quaternary ammonium salt extractant, and the addition volume was 320 L. Ni 2+ The target pH for extraction was 6.8, the main extractant was an oxime extractant, and the dosage volume was 380 L. (Zn) 2+ The target pH value for extraction was 8.0, and the main extractant was an organophosphonic acid extractant with a dosage volume of 350L. Each batch underwent a complete process including dynamic pH control, constant pH settling, main extractant addition, concentration monitoring, phase separation, and metal recovery. After all five batches were extracted, the recovery rate of each target metal reached over 90%, achieving efficient separation and resource utilization of the multi-metal mixture.

[0066] This invention provides a metal extraction system for a mixed solution, comprising: The first unit is used to obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; The second unit is used to analyze the competitive adsorption relationship between each metal ion and the extractant based on the initial component state information, calculate the corresponding coordination bond dissociation energy, and construct the competitive extraction response characteristics of each metal ion. The third unit is used to establish the extraction rate evolution trajectory of each metal ion during pH change based on the competitive extraction response characteristics, and to construct a metal ion separation window by identifying the intersection points between the evolution trajectories. The fourth unit is used to determine the pH control target value for each extraction batch based on the extraction rate evolution trajectory function of the separation window, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. The fifth unit is used to calculate the difference in field stabilization energy between the target metal ion and the candidate extractant when they form a complex based on the ligand field stabilization energy calculation principle, determine the main extractant, and calculate the dosage of the main extractant based on the target metal ion concentration. The sixth unit is used to sequentially perform batch extraction operations on the multi-metal mixture according to the addition sequence of each extraction batch and the corresponding amount of main extractant, so as to obtain the extracted multi-metal mixture.

[0067] A third aspect of the present invention provides an electronic device, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0068] A fourth aspect of the present invention provides a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0069] This invention can be a method, apparatus, system, and / or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for performing various aspects of the invention.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for metal extraction from a mixed solution, characterized in that, include: Obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; Based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed. Based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH change is established, and a metal ion separation window is constructed by identifying the intersection points between the evolution trajectories. Based on the extraction rate evolution trajectory function of the separation window, determine the pH control target value for each extraction batch, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. Based on the principle of ligand field stabilization energy calculation, the field stabilization energy difference between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the main extractant. The dosage of the main extractant is then calculated based on the target metal ion concentration. According to the addition sequence of each extraction batch and the corresponding amount of main extractant, the multi-metal mixture is subjected to batch extraction operations in sequence to obtain the extracted multi-metal mixture.

2. The method according to claim 1, characterized in that, Based on the initial component state information, the competitive adsorption relationship between each metal ion and the extractant is analyzed, the corresponding coordination bond dissociation energy is calculated, and the competitive extraction response characteristics of each metal ion are constructed, including: Based on the initial component state information, the type and concentration values ​​of each metal ion are extracted to obtain the corresponding ion radius and valence electron configuration. According to the ion radius, the bond length distance between each metal ion and the extractant ligand atom is calculated. According to the valence electron configuration, the coordination field splitting energy of each metal ion is calculated. The bond length distance and the coordination field splitting energy are input into the orbital hybridization calculation model to obtain the orbital overlap integral when each metal ion forms a coordination bond with the extractant, and the coordination bond dissociation energy between each metal ion and the extractant is calculated. Based on the concentration value and the coordination bond dissociation energy, the mass action law equation is substituted into the equation to establish a set of competitive equilibrium equations under the condition of coexistence of multiple metal ions. The competitive equilibrium equations are then solved to obtain the coordination occupancy rate of each metal ion with the extractant under different pH conditions. Based on the coordination occupancy rate, the distribution ratio function of each metal ion from the aqueous phase to the organic phase is calculated. The distribution ratio function is differentiated with respect to pH to obtain the extraction rate pH sensitivity coefficient of each metal ion, thereby generating competitive extraction response characteristics.

3. The method according to claim 1, characterized in that, Based on the competitive extraction response characteristics, the extraction rate evolution trajectory of each metal ion during pH changes is established. A metal ion separation window is constructed by identifying the intersection points between these trajectories, including: Based on the competitive extraction response characteristics, a first-order derivative function of the extraction rate of each metal ion with respect to pH is constructed, and a pH variation range is set. A pH sampling sequence is established within the pH variation range. Integrating the first derivative function yields the extraction rate evolution trajectory function of each metal ion. Extracting the extraction rate evolution trajectory function of any two metal ions, a difference function of the extraction rates of the two metal ions is established. The second derivative of the extraction rate difference function is obtained to obtain the extraction rate difference curvature function. The zero point of the extraction rate difference function is solved to obtain the pH coordinates of the intersection point. The pH coordinates of the intersection point are substituted into the extraction rate difference curvature function to obtain the curvature value of the intersection point, and the separation sensitivity index is calculated. Cross points where the sensitivity index exceeds a set threshold are screened and sorted in ascending order to obtain an effective pH boundary point sequence. The pH range is divided into multiple pH intervals. The metal ions with the highest extraction rate in each pH interval are marked as target metal ions and correlated to construct a metal ion separation window.

4. The method according to claim 1, characterized in that, Based on the extraction rate evolution trajectory function of the separation window, the target pH value for each extraction batch is determined, the pH control path for each extraction batch is calculated, and the dosing sequence is determined according to the separation purity requirements of each batch, including: Based on the metal ion separation window, the extraction rate evolution trajectory function of the corresponding target separated metal ion is extracted, and its second derivative is calculated to obtain the extraction rate acceleration function and identify the inflection point position, thereby obtaining the pH control target value for this extraction batch. Based on the pH control target value, the first derivative of the extraction rate difference between the target separated metal ions and non-target metal ions with respect to pH is calculated to obtain the separation selectivity gradient function. The pH control step sequence is calculated, and the pH control step sequence is accumulated and summed to generate a segmented pH control path from the current pH state to the target pH value. The extraction rate evolution trajectory function of the non-target metal ions is integrated along the pH control path to obtain the cumulative co-extraction amount of the non-target metal ions. The impurity introduction coefficient is calculated, and when it exceeds the impurity threshold, a constant pH period is inserted into the pH control path. The operation cycle of each extraction batch is obtained by summing the pH control path duration and the constant pH period duration. The operation cycles are then sequentially accumulated to determine the dosing sequence of each extraction batch.

5. The method according to claim 1, characterized in that, Based on the principle of ligand field stabilization energy calculation, the field stabilization energy difference between the target metal ion and the candidate extractant in each extraction batch is calculated to determine the master extractant. The dosage of the master extractant is then calculated based on the target metal ion concentration, including: Extract the d orbitals, eg electron count, and t2g electron count of the target metal ions in each extraction batch, and calculate the difference in count. Based on the ligand field strength order of each candidate extractant, calculate the energy level splitting distance between the eg and t2g orbitals, and multiply it by the aforementioned difference in count to obtain the ligand field stabilization energy induced by each candidate extractant for the target metal ion. The electron spin multiplicity of the complexes formed by the target metal ions and each candidate extractant is extracted, the electron pairing repulsion energy is calculated, and the net coordination stabilization energy is calculated by combining the ligand field stabilization energy. The candidate extractant with the largest value is selected as the main extractant. For each extraction batch, the required amount of extractant for a single batch is obtained based on the concentration value and coordination stoichiometry of the target metal ion. The extraction rate data of the previous extraction batch is extracted, the concentration of residual metal ions that were not extracted in the previous batch is calculated, and the amount of extractant consumed in the cross-batch is obtained by combining the coordination stoichiometry of the main extractant in the current batch. The dosage of the main extractant is then calculated.

6. The method according to claim 1, characterized in that, According to the addition sequence and corresponding main extractant dosage of each extraction batch, batch extraction operations are sequentially performed on the multi-metal mixture to obtain multiple metals after extraction, including: Based on the addition sequence and corresponding main extractant dosage of each extraction batch, during the pH dynamic control stage, the pH of the multi-metal mixture is adjusted stepwise according to the pH control path. The deviation between the current actual pH value and the target value is monitored. When the deviation exceeds the set deviation threshold, the subsequent pH control step size is corrected. Once the target pH value is reached, the process enters a constant pH settling stage. The pH value of the multi-metal mixture is stabilized at the target pH value. The main extractant is added, and the concentration change rate of the target metal ions in the organic phase is monitored. The organic phase and the aqueous phase are separated, and the target metal ions are recovered from the organic phase. Extract the types and concentration distribution of residual metal ions in the aqueous phase, update the component state information of the multi-metal mixture, repeat the extraction operation until all extraction batches are completed, and obtain the extracted multiple metals.

7. A metal extraction system from a mixed solution for implementing the method as described in any one of claims 1-6, characterized in that, include: The first unit is used to obtain the initial component state information of the multi-metal mixture to be separated, including the types and distribution characteristics of each metal ion; The second unit is used to analyze the competitive adsorption relationship between each metal ion and the extractant based on the initial component state information, calculate the corresponding coordination bond dissociation energy, and construct the competitive extraction response characteristics of each metal ion. The third unit is used to establish the extraction rate evolution trajectory of each metal ion during pH change based on the competitive extraction response characteristics, and to construct a metal ion separation window by identifying the intersection points between the evolution trajectories. The fourth unit is used to determine the pH control target value for each extraction batch based on the extraction rate evolution trajectory function of the separation window, calculate the pH control path for each extraction batch, and determine the dosing sequence according to the separation purity requirements of each batch. The fifth unit is used to calculate the difference in field stabilization energy between the target metal ion and the candidate extractant when they form a complex based on the ligand field stabilization energy calculation principle, determine the main extractant, and calculate the dosage of the main extractant based on the target metal ion concentration. The sixth unit is used to sequentially perform batch extraction operations on the multi-metal mixture according to the addition sequence of each extraction batch and the corresponding amount of main extractant, so as to obtain the extracted multi-metal mixture.

8. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 6.

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