Leaching method for valuable metal in waste lithium battery black powder

Abstract

The invention belongs to the technical field of metal leaching, and provides a method for leaching valuable metals in waste lithium battery black powder, which comprises the following steps of: classifying acid leaching slag samples according to the existence of residual valuable metal insoluble compounds and the distribution concentration degree of the residual valuable metal insoluble compounds; whether the alkaline leaching reaction is optimized or not is judged according to the proportion number of the acid leaching indissolvable samples and the indissolvable concentrated samples in the acid leaching residue samples, and therefore the leaching extraction effect of the valuable metal is guaranteed. The convergence of the valuable metal leaching change curve is analyzed through the constructed valuable metal leaching change curve under different reaction times, so that whether the optimized alkaline leaching reaction time can meet the feasibility of effective leaching of the valuable metal or not is preliminarily judged, and if yes, according to the content and the type of newly added metal elements in the optimized time period, the effective leaching of the valuable metal is determined according to the content and the type of the newly added metal elements in the optimized time period. And after the alkaline leaching reaction time is optimized, the effective leaching feasibility of the valuable metal is finally determined, and the leaching effect of the valuable metal is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal leaching, in particular to a method for leaching valuable metals in black powder of waste lithium batteries. Background Art

[0002] The leaching and extraction of valuable metals in black powder of waste lithium batteries is of great significance in terms of resource conservation, environmental protection, economic benefits and technological progress. However, there are still some shortcomings in the existing technology, for example, the leaching effect is not ideal. Therefore, it is of great significance to study a leaching method for valuable metals in black powder of waste lithium batteries.

[0003] In the journal "Hydrometallurgy" published by Elsevier, the journal theme is "Recovering Valuable Metals from Waste Lithium Batteries by Acid Leaching and Chemical Precipitation". The journal records the process of leaching lithium, cobalt, nickel and other metals from waste lithium batteries by studying sulfuric acid and hydrogen peroxide, and points out the acid leaching reaction and alkaline leaching reaction of valuable metals by sulfuric acid and hydrogen peroxide. The problem is that since there may be residual insoluble compounds of valuable metals in the acid leaching residue after the acid leaching reaction, if the initial alkaline leaching reaction is used for treatment, the extraction of valuable metals cannot ultimately achieve the desired effect. There is a lack of optimization analysis of the alkaline leaching reaction, and there is also a lack of feasibility analysis of the selection of different optimization methods when optimizing the alkaline leaching reaction in combination with the content and type of newly added metal impurities leached after optimization, which further reduces the leaching effect of valuable metals.

[0004] To this end, the present invention provides a method for leaching valuable metals from black powder of waste lithium batteries. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for leaching valuable metals from waste lithium battery black powder, comprising: Screen out acid-leaching insoluble samples from the acid-leaching slag samples according to the test results of the remaining insoluble compounds of valuable metals; Determine the distribution concentration of the remaining insoluble compounds of valuable metals and select insoluble concentrated samples from the insoluble samples in acid leaching; Analyze the quantity ratio of acid-leached insoluble samples and insoluble concentrated samples to determine whether it is necessary to optimize the alkaline leaching reaction. If necessary, analyze the convergence of the valuable metal leaching change curve to preliminarily determine whether the optimized alkaline leaching reaction time can meet the effective leaching of valuable metals. If it is satisfied, the feasibility of optimizing the alkaline leaching reaction time is finally determined by analyzing the change in the content of newly added metal elements in the alkaline leaching solution during the optimization period. If feasible, the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time.

[0007] As a further technical solution of the present invention: If there are residual insoluble compounds of valuable metals in the acid leaching residue sample, the acid leaching residue sample is marked as an acid leaching insoluble sample.

[0008] As a further technical solution of the present invention: Obtain the element distribution map of the marked area in the acid leaching residue sample, and analyze the content of the remaining valuable metal elements after dividing the sub-areas, and perform weighted calculation processing on the range, average absolute deviation and distribution standard deviation of the remaining valuable metal element content in all sub-areas to obtain the distribution concentration value of the acid leaching refractory sample; If the distribution concentration value is greater than or equal to the distribution concentration threshold, the acid-leached insoluble samples corresponding to the distribution concentration value are marked as insoluble concentrated samples.

[0009] As a further technical solution of the present invention: The range is obtained by subtracting the maximum and minimum values ​​of the remaining valuable metal element content; The mean absolute deviation is obtained by summing up the absolute value of the difference between the element content of each sub-region and the average value of the element content of all sub-regions; The distribution standard deviation is calculated by calculating the standard deviation of the remaining valuable metal element contents in all sub-areas.

[0010] As a further technical solution of the present invention: The proportion of acid leaching difficult-to-dissolve samples and difficult-to-dissolve concentrated samples in all acid leaching residue samples is calculated respectively, and the product is processed to obtain the alkali leaching optimization value; If the alkaline leaching optimization value is greater than or equal to the alkaline leaching optimization threshold, it means that the alkaline leaching reaction needs to be optimized.

[0011] As a further technical solution of the present invention: Traverse the slope values ​​of each sampling point on the valuable metal leaching change curve in chronological order; If the slope value falls within the preset slope range, the point corresponding to the slope value on the valuable metal leaching change curve is marked as the initial convergence point, and the collection point after the initial collection point is marked as the analysis collection point; By comparing the slopes of the analysis collection points, the convergence collection points are selected from the analysis collection points; Calculate the percentage of convergence collection points and the variance of the slope data group corresponding to the convergence collection points, and perform weight calculation to obtain the convergence performance value; If the convergence performance value is greater than or equal to the convergence performance threshold, it means that the optimized alkaline leaching reaction time can meet the effective leaching of valuable metals.

[0012] As a further technical solution of the present invention: If the slope value of the analysis acquisition point belongs to the preset slope range, the analysis acquisition point is marked as a convergence acquisition point.

[0013] As a further technical solution of the present invention: The optimized time period is obtained by subtracting the optimized alkaline leaching reaction time from the initial alkaline leaching reaction time; According to the element distribution diagram of the alkaline leaching reaction at the end of the optimization period, the number of types and content of newly added metal elements are counted, and the newly added value of the elements is obtained by processing and analysis; If the element addition value is less than the element addition threshold, it means that it is feasible to optimize the alkaline leaching reaction time, and the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time.

[0014] As a further technical solution of the present invention: The added value of elements is obtained by multiplying the added value of element types and the added value of element content.

[0015] As a further technical solution of the present invention: Count the number of newly added metal elements and compare them with the number of target valuable metal elements to obtain the element type increase value; The content of the newly added metal elements is ratioed with the content of the target valuable metal elements after leaching to obtain the element content increase value.

[0016] The beneficial effects of the present invention are as follows: 1. According to whether there are residual insoluble compounds of valuable metals in the acid leaching residue samples and the distribution concentration of the residual insoluble compounds of valuable metals, the acid leaching residue samples are classified, and according to the proportion of acid leaching insoluble samples and insoluble concentrated samples in the acid leaching residue samples, it is determined whether the alkaline leaching reaction should be optimized, so as to prevent the original alkaline leaching reaction conditions from failing to meet the leaching and extraction requirements of valuable metals, and ensure the leaching and extraction effect of valuable metals.

[0017] 2. By constructing the valuable metal leaching change curve under different reaction times, the convergence of the valuable metal leaching change curve is analyzed, so as to preliminarily judge whether the optimized alkaline leaching reaction time can meet the feasibility of effective leaching of valuable metals. If it is satisfied, the feasibility of effective leaching of valuable metals after the alkaline leaching reaction time is finally determined according to the content and type of newly added metal elements in the optimization period. The present invention improves the leaching effect of valuable metals by optimizing the alkaline leaching reaction time, while reducing the interference of newly added metal impurities on the leaching of valuable metals, thereby further improving the leaching effect of valuable metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 This is a flow chart of the steps of a method for leaching valuable metals from black powder of waste lithium batteries according to Example 1 of the present invention; Figure 2 It is a flow chart of the steps of a method for leaching valuable metals from waste lithium battery black powder described in Example 2-3 of the present invention; Figure 3 It is a data graph of the leaching rate of valuable metals after optimizing the alkaline leaching reaction in a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention; Figure 4 It is a line graph showing the change in leaching rate of valuable metal nickel ions after optimizing the alkaline leaching reaction in a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention; Figure 5 It is a line graph showing the change in the leaching rate of valuable metal cobalt ions after optimizing the alkaline leaching reaction in a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention; Figure 6 It is a line graph showing the change in the leaching rate of valuable metal manganese ions after optimizing the alkaline leaching reaction in a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention; Figure 7 It is a line graph showing the change in the leaching rate of valuable metal lithium ions after optimizing the alkaline leaching reaction in a method for leaching valuable metals from waste lithium battery black powder described in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0021] Example 1 See also Figure 1 As shown, a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention comprises the following steps: S1, pretreatment: the waste lithium battery black powder is pretreated by screening, magnetic separation, etc. to remove large impurities and magnetic substances, and then dried and ground; S2, preparation of acidic leaching solution: prepare a sulfuric acid solution with a sulfuric acid concentration of 1.5 - 2.5 mol / L, and add hydrogen peroxide (volume fraction of 8% - 12%) as an oxidant; S3, acid leaching reaction: the pretreated black powder is mixed with the leaching solution at a liquid-solid ratio of 6-8 mL / g, and the leaching reaction is carried out at a temperature of 50-70°C and a stirring speed of 300-500 r / min, and the reaction time is 1.5-2.5 hours; S4, acid leaching solid-liquid separation: after the leaching reaction is completed, solid-liquid separation is performed by filtering or centrifugation to obtain acid leaching liquid and acid leaching residue; S5, preparation of alkaline leaching solution: preparing a sodium hydroxide solution with a concentration of 2-4 mol / L as an alkaline leaching solution; S6, alkaline leaching reaction: adding the acid leaching residue obtained from the first leaching into the alkaline leaching solution, controlling the liquid-solid ratio to be 4-6 mL / g, and carrying out the alkaline leaching reaction at a temperature of 80-100°C and a stirring speed of 200-400 r / min for a reaction time of 2-3 hours; S7, alkali leaching solid-liquid separation: After the reaction is completed, solid-liquid separation is performed again by filtration or centrifugation to obtain alkali leaching solution and alkali leaching residue. The alkali leaching solution contains valuable metals dissolved in the alkali solution, wherein the valuable metals include but are not limited to lithium, cobalt, nickel, manganese, etc.

[0022] Example 2 See also Figure 2 As shown, based on Example 1, a method for leaching valuable metals from waste lithium battery black powder according to an embodiment of the present invention comprises the following steps: Step 1: In S4 described in Example 1, a plurality of acid leaching slag samples are extracted from the acid leaching slag, and the residual insoluble compounds of valuable metals are detected in each acid leaching slag sample by SEM-EDS (scanning electron microscope-energy dispersive X-ray spectrometer), and the acid leaching insoluble samples are screened out from the acid leaching slag samples according to the detection results; In the step 1, the method of detecting the remaining insoluble compounds of valuable metals in each acid leaching residue sample by SEM-EDS (scanning electron microscope-energy dispersive X-ray spectrometer) is as follows: The prepared acid leaching residue sample is placed in a scanning electron microscope. First, a low magnification (such as 100-500 times) is used to quickly scan the entire acid leaching residue sample area to understand the overall distribution and general morphological characteristics of the sample, and mark the area where special structures or particles may exist; for the marked area, switch to a high magnification (such as 1000-10000 times or even higher) for detailed observation, and mark the particles with regular geometric shapes that are obviously different from the surrounding matrix as suspected valuable metal insoluble compounds. For example, metal oxides may present a blocky, spherical or flaky crystal morphology; metal sulfides may have unique textures or crystal plane structures; when particles suspected of being valuable metal insoluble compounds are found in the SEM image, EDS is used to perform point-by-point elemental analysis on the particle, focusing the electron beam on the target particle, collecting and analyzing the X-rays emitted by it. The energy and intensity of the radiation are used to determine the types of elements contained in the particles and their relative contents, and finally to detect whether there are residual insoluble compounds of valuable metals in the acid leaching residue sample, wherein the insoluble compounds of valuable metals include but are not limited to hydroxides and metal oxides, such as aluminum hydroxide Al (OH) 3, manganese dioxide (MnO2), etc.; In the step 1, the method of screening out the acid leaching insoluble samples from the acid leaching residue samples according to the test results is: If there are residual insoluble compounds of valuable metals in the acid leaching residue sample, the acid leaching residue sample is marked as an acid leaching insoluble sample; If there are no residual insoluble compounds of valuable metals in the acid leaching residue sample, the acid leaching residue sample is not marked as an acid leaching insoluble sample; Step 2: judging the distribution concentration of the remaining insoluble compounds of valuable metals in the insoluble samples through the element distribution diagram of the insoluble samples after acid leaching, and screening the insoluble concentrated samples from the insoluble samples after acid leaching according to the judgment result; The method for obtaining the element distribution map of the acid-leached insoluble sample in step 2 is: For acid-immersed refractory samples, the EDS element surface scanning function is activated on the marked area. The electron beam will scan point by point in the set scanning area. At the same time, the EDS detector will collect the characteristic X-ray signals emitted by different elements at each point. According to the characteristic X-ray energy range of different elements, the signals are classified and identified, and the signal intensity of each element is converted into a corresponding color or grayscale value, thereby generating an element distribution map. It should be noted that the element distribution map includes the various marked areas in the acid-leached refractory samples; In the step 2, the distribution concentration of the remaining insoluble compounds of valuable metals in the insoluble sample of acid leaching is determined by the element distribution diagram of the insoluble sample of acid leaching: On the element distribution map, the image is divided into several sub-areas of equal size. For example, the element distribution map can be divided into 10×10 or 20×20 grid sub-areas. For each sub-area, the content data of the remaining valuable metal elements are obtained by SEM-EDS analysis. Extract the maximum and minimum values ​​of the remaining valuable metal element contents in all sub-areas and calculate the range; It should be noted that the larger the range, the greater the difference in element content between different regions, indicating that the distribution of insoluble compounds of valuable metals is more uneven and the concentration in the region is higher; Calculate the absolute value of the difference between the element content of each sub-region and the average value of the element content of all sub-regions, sum and average them to obtain the average absolute deviation; It should be noted that the larger the mean absolute deviation, the greater the dispersion of element content in different regions, the more uneven the distribution, and the higher the concentration; Based on the remaining valuable metal element contents in all sub-areas, the distribution standard deviation of the remaining valuable metal element contents is calculated by the standard deviation formula; It should be noted that the larger the distribution standard deviation, the greater the fluctuation of the element content between different sub-regions, that is, the more uneven the distribution is, and the insoluble compounds of valuable metals are concentrated; the smaller the standard deviation, the relatively stable element content between each sub-region and the more uniform the distribution; The range, mean absolute deviation and distribution standard deviation of the remaining valuable metal elements in all sub-areas were weighted and processed to obtain the distribution concentration value of the acid-leached refractory samples, where the weight factors corresponding to the range of the valuable metal elements were 1.316, the weight factor corresponding to the mean absolute deviation was 1.28, and the weight factor corresponding to the distribution standard deviation was 1.017. comparing the distribution concentration value to a distribution concentration threshold; If the distribution concentration value is greater than or equal to the distribution concentration threshold, the acid-leached insoluble sample corresponding to the distribution concentration value is marked as an insoluble concentration sample; If the distribution concentration value is less than the distribution concentration threshold, no operation is performed; It should be noted that the valuable metal element content of each sub-region in the element distribution map corresponding to the acid leaching sample is obtained by using the element distribution map of the acid leaching sample and combining with EDS scanning and other technologies. The data values ​​such as the range, average absolute deviation and distribution standard deviation of the valuable metal element content of all sub-regions are calculated, and the weights are comprehensively calculated to judge the distribution concentration of the remaining valuable metal insoluble compounds in the acid leaching insoluble sample, and to judge whether there are remaining valuable metal insoluble compounds in the acid leaching residue sample. The comprehensive purpose is to judge whether the alkaline leaching reaction needs to be optimized by analyzing whether there are remaining valuable metal insoluble compounds in the acid leaching residue sample and the distribution concentration, so as to prevent the original alkaline leaching reaction conditions from failing to make the extraction of valuable metals meet the expected effect due to the presence of remaining valuable metal insoluble compounds. Therefore, the present application scheme performs a judgment and analysis of the presence and concentrated distribution of remaining valuable metals before the alkaline leaching reaction to ensure the extraction effect of valuable metals. Step 3: Analyze the quantity ratio of acid-leached insoluble samples and insoluble concentrated samples to determine whether alkaline leaching optimization is needed. If necessary, generate an alkaline leaching optimization signal; The process of determining whether alkaline leaching optimization is required in step 3 includes: For the acid leaching insoluble samples and insoluble concentrated samples obtained in the above steps, respectively calculate the quantity ratios of the acid leaching insoluble samples and insoluble concentrated samples in all acid leaching residue samples, and perform product processing to obtain the alkali leaching optimization value; Compare the obtained alkali leaching optimization value with the alkali leaching optimization threshold: If the alkaline leaching optimization value is greater than or equal to the alkaline leaching optimization threshold, it means that among all the acid leaching residue samples, the number of samples with residual insoluble compounds of valuable metals and the number of samples with concentrated distribution of residual insoluble compounds of valuable metals account for a large proportion, which affects the alkaline leaching reaction and the effect of valuable metal extraction, and an alkaline leaching optimization signal is generated; If the alkaline leaching optimization value is less than the alkaline leaching optimization threshold, it means that among all the acid leaching residue samples, the number of samples with residual insoluble compounds of valuable metals and the number of samples with concentrated distribution of residual insoluble compounds of valuable metals account for a small proportion, which does not affect the alkaline leaching reaction and the effect of valuable metal extraction, and no operation is performed; The technical solution of the embodiment of the present invention is: according to whether there are residual insoluble compounds of valuable metals in the acid leaching residue samples and the distribution concentration of the residual insoluble compounds of valuable metals, the acid leaching residue samples are classified, and according to the proportion of acid leaching insoluble samples and insoluble concentrated samples in the acid leaching residue samples, it is judged whether to optimize the alkaline leaching reaction, thereby preventing the original alkaline leaching reaction conditions from failing to meet the leaching and extraction requirements of valuable metals, and ensuring the leaching and extraction effect of valuable metals.

[0023] Example 3 See also Figure 2 As shown, based on Example 1 and Example 2, the embodiment of the present invention is aimed at the alkali leaching optimization signal, and the alkaline leaching reaction needs to be optimized. Analysis is performed. Since there are residual valuable metal insoluble compounds in the acid leaching residue, it is necessary to optimize the reaction conditions, but the first consideration is to optimize the reaction time, without changing other alkaline leaching solutions, reaction temperature and other conditions, reducing the optimization operation steps, and improving the optimization efficiency. Therefore, the embodiment of the present invention is analyzed and processed for the optimization of the reaction time. The method for leaching valuable metals in waste lithium battery black powder described in the embodiment of the present invention comprises the following steps: Step 4: Based on the alkaline leaching optimization signal, construct the valuable metal leaching change curve under different reaction times, and preliminarily judge whether the optimized alkaline leaching reaction time can meet the effective leaching of valuable metals by analyzing the convergence of the valuable metal leaching change curve. If it does, generate a preliminary feasible signal and determine the optimized alkaline leaching reaction time; In the step 4, the leaching rate of valuable metals under different reaction times is obtained, and a valuable metal leaching change curve is constructed with the reaction time as the X-axis and the valuable metal leaching rate as the Y-axis. It should be noted that the different reaction times can be 1h, 1.25h, 1.5h, 1.75, 2h, 2.25h, 3h, 3.25h, 3.5h, 3.75h, 4h; usually it will not exceed 12h; Traversing the slope values ​​of each collected point on the valuable metal leaching change curve in chronological order, and comparing them with the preset slope range; It should be noted that the collection points are evenly distributed on the valuable metal leaching variation curve; If the slope value falls within the preset slope range, the point corresponding to the slope value on the valuable metal leaching change curve is marked as the initial convergence point, and the collection point after the initial collection point is marked as the analysis collection point; It should be noted that the time point of the analytical collection point is after the time point of the initial collection point; If the slope value does not fall within the preset slope range, continue to traverse the next acquisition point; It should be noted that the preset slope range is set by those skilled in the art for the purpose of determining the convergence of the valuable metal leaching variation curve; Based on the analysis acquisition point, the slope value of the analysis acquisition point is compared with a preset slope range; If the slope value of the analysis acquisition point falls within the preset slope range, the analysis acquisition point is marked as a convergence acquisition point; If the slope value of the analysis acquisition point does not belong to the preset slope range, the analysis acquisition point is marked as a non-convergent acquisition point; Calculate the proportion of convergence acquisition points in the analysis acquisition points, and integrate the slope values ​​corresponding to the convergence acquisition points into a slope data group; The convergence performance value is obtained by weighting the proportion of the convergence collection points in the analysis collection points and the variance value of the slope data group; Among them, the weight factor corresponding to the proportion of convergence collection points in the analysis collection points is 1.013, and the weight factor corresponding to the variance value of the slope data group is 1.126; It should be noted that the convergence performance value is calculated by the proportion of the number of convergence collection points in the analysis collection points and the variance value of the slope data group. The higher the proportion of the number of convergence collection points in the analysis collection points, the more convergence collection points there are from the initial convergence point, and the valuable metal leaching change curve converges to a gentle level. The smaller the overall variance of the slope value corresponding to the convergence collection point, the more stable the slope of the convergence collection point is, and the valuable metal leaching change curve converges to a gentle level. comparing the convergence performance value to a convergence performance threshold; If the convergence performance value is greater than or equal to the convergence performance threshold, it means that the valuable metal leaching curve converges to a gentle level, and the leaching rate can be stabilized by optimizing the reaction time, thereby meeting the effective leaching of valuable metals, and the time corresponding to the initial convergence point is used as the optimized alkaline leaching reaction time to generate a preliminary feasible signal; If the convergence performance value is less than the convergence performance threshold, it means that the valuable metal leaching change curve has not converged to a flat state, and the next collection point will continue to be traversed. If there is no initial convergence point or the convergence performance values ​​are all less than the convergence performance threshold until all collection points are traversed, it means that the optimized alkaline leaching reaction time cannot meet the effective leaching of valuable metals, and other optimization methods will be switched, including but not limited to: reaction temperature, stirring speed, etc.; It should be noted that when there are insoluble compounds of valuable metals in the acid leaching residue, the optimized reaction time is usually longer than the initial alkaline leaching reaction time (2h-3h); It should be noted that the above step 4 preliminarily determines whether the optimized alkaline leaching reaction time can meet the feasibility of effective leaching of valuable metals by analyzing the convergence of the valuable metal leaching change curve. If it can be met, on the one hand, the optimization efficiency of the alkaline leaching reaction can be improved. On the other hand, the final determination after the preliminary judgment is qualified is convenient to provide a basis for the alkaline leaching optimization strategy. If the optimized reaction time cannot be met, other optimization methods can be switched in time. Step 5: Based on the preliminary feasible signal, the optimized period is determined according to the optimized alkaline leaching reaction time, and the feasibility of optimizing the alkaline leaching reaction time is finally determined by analyzing the change of the content of the newly added metal elements in the alkaline leaching solution during the optimized period. If feasible, the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time; The optimized time period in step 5 is obtained by subtracting the optimized alkaline leaching reaction time from the initial alkaline leaching reaction time; The process of finally determining the feasibility of optimizing the alkaline leaching reaction time by analyzing the change of the newly added metal content in the alkaline leaching solution during the optimization period in step 5 includes: According to the element distribution diagram of the alkaline leaching reaction at the end of the optimization period, the content of the newly added metal elements is obtained in combination with SEM-EDS analysis, where the newly added metal elements are metal elements other than the target valuable metal elements. For example, cobalt ions may form new complexes with hydroxide ions and other anions in the solution, and these complexes may further decompose or react with other substances under certain conditions to release other metal elements; It should be noted that the target valuable metal elements represent the valuable metal elements initially contained in the acid leaching residue; According to the element distribution diagram of the alkaline leaching reaction at the end of the optimization period, the number of newly added metal elements is counted, and the number of target valuable metal elements is compared to obtain the element type increase value; The content of the newly added metal element is compared with the content of the target valuable metal element after leaching to obtain the element content increase value; The added value of the element type is multiplied by the added value of the element content to calculate the added value of the element; It should be noted that the purpose of obtaining the element added value is that the element added value is obtained by calculating and analyzing the type and content of the newly added metal elements. The element added value can be used to determine whether the alkaline leaching reaction after the optimized reaction time will be affected by the newly added metal impurities when extracting valuable metals; Compare the element addition value with the element addition threshold; If the element addition value is greater than or equal to the element addition threshold, it means that after optimizing the alkaline leaching reaction time, other newly appeared metal elements are added to the leached valuable metals with a large content and variety, which affects the leaching effect of valuable metals. Therefore, it is not feasible to optimize the alkaline leaching reaction time; If the element addition value is less than the element addition threshold, it means that it is feasible to optimize the alkaline leaching reaction time, and the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time. For example, Figure 3-Figure 7 As shown, it reflects the change of valuable metal leaching rate corresponding to the alkaline reaction time before and after optimization; The technical solution of the embodiment of the present invention is: by constructing a valuable metal leaching change curve under different reaction times, the convergence of the valuable metal leaching change curve is analyzed, so as to preliminarily judge whether the optimized alkaline leaching reaction time can meet the feasibility of effective leaching of valuable metals. If it is satisfied, the feasibility of effective leaching of valuable metals after the alkaline leaching reaction time is finally determined according to the content and type of newly added metal elements in the optimization period. The present invention improves the leaching effect of valuable metals by optimizing the alkaline leaching reaction time, while reducing the interference of newly added metal impurities on the leaching of valuable metals, thereby further improving the leaching effect of valuable metals.

[0024] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for leaching valuable metals from waste lithium battery black powder, characterized in that: include: Screen out acid-leaching insoluble samples from the acid-leaching slag samples according to the test results of the remaining insoluble compounds of valuable metals; Determine the distribution concentration of the remaining insoluble compounds of valuable metals and select insoluble concentrated samples from the insoluble samples in acid leaching; Analyze the quantity ratio of acid-leached insoluble samples and insoluble concentrated samples to determine whether it is necessary to optimize the alkaline leaching reaction. If necessary, analyze the convergence of the valuable metal leaching change curve to preliminarily determine whether the optimized alkaline leaching reaction time can meet the effective leaching of valuable metals. If it is satisfied, the feasibility of optimizing the alkaline leaching reaction time is finally determined by analyzing the change in the content of newly added metal elements in the alkaline leaching solution during the optimization period. If feasible, the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time.

2. The method for leaching valuable metals from waste lithium battery black powder according to claim 1, characterized in that: If there are residual insoluble compounds of valuable metals in the acid leaching residue sample, the acid leaching residue sample is marked as an acid leaching insoluble sample.

3. The method for leaching valuable metals from waste lithium battery black powder according to claim 1, characterized in that: Obtain the element distribution map of the marked area in the acid leaching residue sample, and analyze the content of the remaining valuable metal elements after dividing the sub-areas, and perform weighted calculation processing on the range, average absolute deviation and distribution standard deviation of the remaining valuable metal element content in all sub-areas to obtain the distribution concentration value of the acid leaching refractory sample; If the distribution concentration value is greater than or equal to the distribution concentration threshold, the acid-leached insoluble samples corresponding to the distribution concentration value are marked as insoluble concentrated samples.

4. The method for leaching valuable metals from waste lithium battery black powder according to claim 3, characterized in that: The range is obtained by subtracting the maximum and minimum values ​​of the remaining valuable metal element content; The mean absolute deviation is obtained by summing up the absolute value of the difference between the element content of each sub-region and the average value of the element content of all sub-regions; The distribution standard deviation is calculated by calculating the standard deviation of the remaining valuable metal element contents in all sub-areas.

5. The method for leaching valuable metals from waste lithium battery black powder according to claim 1, characterized in that: The proportion of acid leaching difficult-to-dissolve samples and difficult-to-dissolve concentrated samples in all acid leaching residue samples is calculated respectively, and the product is processed to obtain the alkali leaching optimization value; If the alkali leaching optimization value is greater than or equal to the alkali leaching optimization threshold, it means that the optimization of the alkaline leaching reaction is required.

6. The method for leaching valuable metals from waste lithium battery black powder according to claim 1, characterized in that: Traverse the slope values ​​of each sampling point on the valuable metal leaching change curve in chronological order; If the slope value falls within the preset slope range, the point corresponding to the slope value on the valuable metal leaching change curve is marked as the initial convergence point, and the collection point after the initial collection point is marked as the analysis collection point; By comparing the slopes of the analysis collection points, the convergence collection points are selected from the analysis collection points; Calculate the percentage of convergence collection points and the variance of the slope data group corresponding to the convergence collection points, and perform weight calculation to obtain the convergence performance value; If the convergence performance value is greater than or equal to the convergence performance threshold, it means that the optimized alkaline leaching reaction time can meet the effective leaching of valuable metals.

7. The method for leaching valuable metals from waste lithium battery black powder according to claim 6, characterized in that: If the slope value of the analysis acquisition point belongs to the preset slope range, the analysis acquisition point is marked as a convergence acquisition point.

8. The method for leaching valuable metals from waste lithium battery black powder according to claim 1, characterized in that: The optimized time period is obtained by subtracting the optimized alkaline leaching reaction time from the initial alkaline leaching reaction time; According to the element distribution diagram of the alkaline leaching reaction at the end of the optimization period, the number of types and content of newly added metal elements are counted, and the newly added value of the elements is obtained by processing and analysis; If the element addition value is less than the element addition threshold, it means that it is feasible to optimize the alkaline leaching reaction time, and the alkaline leaching reaction is adjusted according to the optimized alkaline leaching reaction time.

9. The method for leaching valuable metals from waste lithium battery black powder according to claim 8, characterized in that: The added value of elements is obtained by multiplying the added value of element types and the added value of element content.

10. The method for leaching valuable metals from waste lithium battery black powder according to claim 9, characterized in that: Count the number of newly added metal elements and compare them with the number of target valuable metal elements to obtain the element type increase value; The content of the newly added metal elements is ratioed with the content of the target valuable metal elements after leaching to obtain the element content increase value.

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