Method for removing copper, iron and aluminum in waste battery leachate through co-extraction method

Abstract

The invention provides a method for removing copper, iron and aluminum in waste battery leachate through a co-extraction method. The method comprises the following steps: firstly, mixing a certain extracting agent, a certain modifier and a diluent to obtain an extracting solvent; then mixing the extracting solvent with a saponifying agent for saponification to obtain a saponified extracting solvent; then, mixing the saponification extraction solvent and the waste battery leachate for extraction to respectively obtain a raffinate water phase and a loaded organic phase; and finally, carrying out reverse extraction or washing and reverse extraction to respectively obtain a reverse extraction solution and a blank organic phase. Compared with the prior art, the process is simplified, impurities (aluminum, iron and copper) can be separated from other metal ions through one-step selective co-extraction, the extraction system is good in phase separation, heavy metal entrainment is effectively reduced, the loss rate of valuable metals (lithium, nickel, cobalt and manganese) in the impurity removal process is reduced, the metal recovery rate is increased, and the method is suitable for industrial production. And no slag is generated in the method, and waste slag treatment is not needed.

Description

Technical Field

[0001] The invention relates to the field of battery recycling, and in particular to a method for removing copper, iron and aluminum from waste battery leachate by a co-extraction method. Background Art

[0002] Lithium-ion batteries have shown significant application potential in the fields of electric vehicles and electronic devices due to their superior safety performance and excellent electrochemical properties. In recent years, under the influence of multiple factors such as energy, environment, and technology, the new energy vehicle industry has shown explosive development, which has directly led to the rapid growth of lithium-ion power battery production and installation scale. However, due to the rapid growth in electric vehicle sales, it has also led to an increase in waste lithium-ion batteries. In 2020, the total amount of waste lithium-ion batteries was close to 250,000 tons, and by 2035, it is expected to exceed 6.76 million tons. These waste lithium batteries include toxic and corrosive electrolytes that need to be properly handled, otherwise they will have a negative impact on the environment and human health. In addition, waste lithium-ion batteries are also regarded as important secondary mineral resources because they contain much more valuable metals than natural ores (such as 5%-10% nickel, 20% cobalt and 5%-7% lithium. Therefore, recycling waste lithium-ion batteries has significant environmental and economic benefits. Copper, aluminum and iron are the main impurities in the positive electrode materials of waste lithium-ion batteries. Their presence greatly affects the purity of the recycled products. Therefore, it is necessary to use a suitable method to separate copper, aluminum and iron from the waste battery leachate to obtain high-purity nickel, cobalt, manganese and lithium leachate for subsequent high-purity product recovery.

[0003] The prior art mostly removes copper by displacement method, and then removes iron and aluminum by precipitation method. For example, patent application CN 111471864 (a method for recovering copper, aluminum and iron from waste lithium-ion battery leachate) mainly includes: adding manganese powder to waste lithium-ion battery leachate to remove copper, filtering to obtain copper-removed liquid and sponge copper; adding nickel carbonate and / or cobalt hydroxide to the obtained copper-removed liquid to adjust the pH value, stirring and filtering to obtain aluminum-removed liquid and aluminum slag; adding an oxidant to the aluminum-removed liquid, stirring to obtain ferrous iron-removed liquid; using goethite method to remove iron, and obtaining purified liquid with copper, aluminum and iron removed. Patent application CN110492193 (a method for recovering iron and aluminum from waste ternary lithium-ion batteries) mainly includes: adding iron powder to waste battery leachate, removing copper by displacement method; adding an oxidant and alkali metal carbonate to the copper-removed liquid in sequence, keeping warm and aging, and filtering to obtain iron-aluminum slag and purified liquid.

[0004] However, in the above-mentioned prior art, copper is removed by replacement method, but the copper removal rate is not high, and subsequent refining is required to remove copper. The iron and aluminum slag obtained by hydrolysis is difficult to filter and can only be treated as hazardous waste. In addition, the prior art uses multiple steps to remove impurities, which is not only complicated to operate, but also carries nickel, cobalt, manganese, and lithium, resulting in a large loss of valuable metals. Summary of the invention

[0005] In view of this, the present invention provides a method for removing copper, iron and aluminum from waste battery leachate by co-extraction. The method of the present invention has good extraction and impurity removal effect, less heavy metal entrainment, no slag generation, short process flow and high metal recovery rate.

[0006] The present invention provides a method for removing copper, iron and aluminum from waste battery leachate by a co-extraction method, comprising the following steps:

[0007] A) mixing an extractant, a modifier and a diluent to obtain an extraction solvent;

[0008] Wherein, the extractant is secondary octylphenoxy substituted acetic acid;

[0009] The improver is tributyl phosphate and / or isooctyl alcohol;

[0010] B) mixing the extraction solvent with a saponifying agent to saponify the mixture to obtain a saponified extraction solvent;

[0011] C) Extraction: Mixing the saponification extraction solvent and the waste battery leachate for extraction to obtain a raffinate water phase and a loaded organic phase respectively;

[0012] D) comprising step DM) stripping, or step DN) washing and stripping;

[0013] DM) Stripping:

[0014] The loaded organic phase is stripped using a stripping agent to obtain a stripping solution and a blank organic phase respectively;

[0015] DN) Washing and stripping:

[0016] Washing: washing the loaded organic phase to obtain a washing residue and a washing organic phase;

[0017] Stripping: Stripping the washed organic phase with a stripping agent to obtain a stripping solution and a blank organic phase.

[0018] Preferably, in step A), the volume percentage concentration of the extractant in the obtained extraction solvent is 10% to 40%, and the volume percentage concentration of the improver is 5% to 20%.

[0019] Preferably, in step B), the saponifying agent is at least one of ammonia water, sodium hydroxide, sodium carbonate and ammonium carbonate.

[0020] Preferably, in step B), the saponification degree of the saponification extraction solvent is 10% to 40%.

[0021] Preferably, in step B), the volume ratio of the saponification extraction solvent to the waste battery leaching solution is 3:1 to 1:5.

[0022] Preferably, in step C), before the extraction, the pH value of the waste battery leachate is adjusted;

[0023] The pH value is adjusted to a value between 1.5 and 2.5.

[0024] Preferably, in step DN), the washing agent used in the washing is sulfuric acid;

[0025] The concentration of the sulfuric acid is 0.02-0.2 mol / L.

[0026] Preferably, in step DN), the volume ratio of the washed organic phase to the stripping agent is 3:1 to 10:1.

[0027] Preferably, in step DM), the volume ratio of the loaded organic phase to the stripping agent is 3:1 to 10:1.

[0028] Preferably, in step C), the extraction is countercurrent extraction; the extraction is single-stage extraction or multi-stage extraction; wherein the number of stages of the multi-stage extraction is preferably 3 to 6;

[0029] In step DN), the washing is countercurrent washing; the washing is single-stage washing or multi-stage washing; wherein the number of stages of the multi-stage washing is 3 to 6;

[0030] In step DN), the stripping is multi-stage cross-current stripping; the number of stages of the multi-stage cross-current stripping is 4 to 6;

[0031] In step DM), the stripping is multi-stage cross-current stripping; the number of stages of the multi-stage cross-current stripping is 4 to 6.

[0032] The method provided by the present invention first mixes a certain extractant, a certain improver and a diluent to obtain an extraction solvent; then the extraction solvent is mixed with a saponifier for saponification to obtain a saponified extraction solvent; thereafter, the saponified extraction solvent and the waste battery leachate are mixed for extraction to obtain a raffinate aqueous phase and a loaded organic phase, respectively; finally, stripping is performed, or washing and stripping are performed to obtain a stripping solution and a blank organic phase, respectively. Compared with the prior art, the present invention simplifies the process, and can achieve the separation of impurities (aluminum, iron and copper) from other metal ions through a one-step selective co-extraction. Moreover, the extraction system of the present invention has good phase separation, effectively reduces heavy metal entrainment, reduces the loss rate of valuable metals (lithium, nickel, cobalt, manganese) during the impurity removal process, and improves the metal recovery rate. Moreover, the method of the present invention does not produce slag, and does not require waste slag treatment.

[0033] The experimental results show that the method of the present invention can extract more than 99.7% of Al, more than 99.7% of Cu, and 100% of Fe into the organic phase in the extraction step, and the impurity removal effect is good. At the same time, the total loss rate of nickel, cobalt, manganese and lithium in the process is below 0.68%, which can effectively reduce the loss rate of valuable metals. In the stripping step, the stripping rates of iron, copper and aluminum in the organic phase are all over 99.5%, which can effectively remove impurity metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 The present invention is a process flow chart of the method for removing copper, iron and aluminum from waste battery leachate by the co-extraction method. DETAILED DESCRIPTION

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0037] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0038] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0039] Herein, when it comes to numerical ranges, unless otherwise specified, the numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0040] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 0.02~0.2mol / L means that the units of the left endpoint "0.02" and the right endpoint "0.2" are both mol / L.

[0041] Only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0042] The present invention provides a method for removing copper, iron and aluminum from waste battery leachate by a co-extraction method, comprising the following steps:

[0043] A) mixing an extractant, a modifier and a diluent to obtain an extraction solvent;

[0044] Wherein, the extractant is secondary octylphenoxy substituted acetic acid;

[0045] The improver is tributyl phosphate and / or isooctyl alcohol;

[0046] B) mixing the extraction solvent with a saponifying agent to saponify the mixture to obtain a saponified extraction solvent;

[0047] C) Extraction: Mixing the saponification extraction solvent and the waste battery leachate for extraction to obtain a raffinate water phase and a loaded organic phase respectively;

[0048] D) comprising step DM) stripping, or step DN) washing and stripping;

[0049] DM) Stripping:

[0050] Stripping the loaded organic phase with a stripping agent to obtain a stripping solution and a blank organic phase respectively;

[0051] DN) Washing and stripping:

[0052] Washing: washing the loaded organic phase to obtain a washing residue and a washing organic phase;

[0053] Stripping: Stripping the washed organic phase with a stripping agent to obtain a stripping solution and a blank organic phase.

[0054] See also Figure 1 , Figure 1 The present invention is a process flow chart of the method for removing copper, iron and aluminum from waste battery leachate by the co-extraction method.

[0055] About step A) :

[0056] A) The extractant, the improver and the diluent are mixed to obtain an extraction solvent.

[0057] In the present invention, the extractant is sec-octylphenoxy substituted acetic acid (CA-12). The present invention has no special restrictions on the source of the extractant, and it can be a commercial product.

[0058] In the present invention, the improver is tributyl phosphate (TBP) and / or isooctyl alcohol, preferably tributyl phosphate (TBP). The present invention has no particular limitation on the source of the improver, and it can be a commercial product.

[0059] In the present invention, the diluent is preferably at least one of sulfonated kerosene, n-hexane and cyclohexane, preferably sulfonated kerosene. The present invention has no particular limitation on the source of the diluent, and any commercial product can be used.

[0060] The present invention has no special restrictions on the method of mixing the extractant, the improver and the diluent, and the materials can be mixed uniformly in a conventional mixing method in the art to obtain the extraction solvent.

[0061] In the present invention, the volume percentage concentration of the extractant in the obtained extraction solvent is preferably 10% to 40% (herein, % represents vol%), and can be specifically 10%, 15%, 20%, 25%, 30%, 35%, 40%. In the present invention, the volume percentage concentration of the improver in the extraction solvent is preferably 5% to 20% (herein, % represents vol%), and can be specifically 5%, 10%, 15%, 20%.

[0062] About step B) :

[0063] B) mixing the extraction solvent with a saponifying agent to perform saponification to obtain a saponified extraction solvent.

[0064] In the present invention, the saponifying agent is preferably at least one of ammonia water, sodium hydroxide, sodium carbonate and ammonium carbonate, and more preferably ammonia water. The concentration of the ammonia water is preferably 2 to 5 mol / L, specifically 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L.

[0065] In the present invention, the amount of the saponifier is preferably such that the saponification degree of the extraction solvent reaches 10% to 40%, specifically 10%, 15%, 20%, 25%, 30%, 35%, 40%. After saponification by the saponifier, a saponified extraction solvent is obtained.

[0066] About step C) :

[0067] C) Extraction: The saponification extraction solvent and the waste battery leaching solution are mixed for extraction to obtain a raffinate water phase and a loaded organic phase respectively.

[0068] In the present invention, the waste battery leachate refers to the leachate of waste batteries, and the method for obtaining the waste battery leachate is not particularly limited, and it can be obtained according to the conventional method in the art. Generally, the waste battery leachate is obtained by the following method: dismantling and crushing the waste batteries, and then impregnating them with acid to obtain the waste battery leachate. In the present invention, the waste battery leachate is a waste lithium-ion battery leachate, which contains nickel, cobalt, manganese, lithium, iron, copper, aluminum, etc.

[0069] In the present invention, before extraction, the pH value of the waste battery leachate is preferably adjusted. In the present invention, the pH value is preferably adjusted to a pH value of 1.5 to 2.5, specifically 1.5, 2.0, or 2.5. In the present invention, the type of the regulator used to adjust the pH value is not particularly limited, and it can be a conventional regulator, specifically at least one of sodium hydroxide, ammonia water, and sodium carbonate.

[0070] In the present invention, the waste battery leachate is the extract to be extracted, which is the extraction water phase; the saponified extraction solvent is used as the extraction organic phase. In the present invention, the saponified extraction solvent is mixed with the waste battery leachate in a certain ratio. Specifically, the volume ratio of the saponified extraction solvent to the waste battery leachate (i.e., the organic phase / water phase ratio, O / A ratio) is preferably 3:1 to 1:5. In the present invention, there is no special restriction on the temperature conditions for mixing the saponified extraction solvent with the waste battery leachate, and it can be carried out at room temperature, which can be 20 to 25°C, specifically 25°C. The above two can be mixed by stirring or shaking. Among them, the stirring and mixing rate is preferably 300 to 500rpm, specifically 300rpm, 350rpm, 400rpm, 450rpm, 500rpm. The mixing time is preferably 10 to 30min, specifically 10min, 15min, 20min, 25min, 30min.

[0071] In the process of mixed extraction of the above-mentioned extraction aqueous phase (i.e., waste battery leachate) and the extraction organic phase (i.e., saponified extraction solvent), iron, copper, and aluminum in the waste battery leachate are extracted into the organic phase (forming an organic phase loaded with impurity metals, i.e., a loaded organic phase), and nickel, cobalt, manganese, and lithium are retained in the aqueous phase (obtaining the aqueous phase remaining after extraction and impurity removal, i.e., the raffinate aqueous phase), so that the impurities (iron, copper, and aluminum) in the waste battery leachate are separated from the valuable metals (nickel, cobalt, manganese, and lithium), thereby obtaining the raffinate aqueous phase and the loaded organic phase, respectively.

[0072] In the present invention, the extraction is preferably countercurrent extraction. The extraction can be a single-stage extraction or a multi-stage extraction. The number of stages of the multi-stage extraction is preferably 3 to 6. After the countercurrent extraction reaches extraction equilibrium, the phases are allowed to stand for phase separation to obtain a raffinate aqueous phase and a loaded organic phase.

[0073] About step D) :

[0074] In the present invention, step D) has two schemes: DM) stripping, or DN) washing and stripping.

[0075] [About step DN]: washing and stripping.

[0076] Washing: washing the loaded organic phase to obtain a washing residue and a washing organic phase respectively.

[0077] The present invention obtains a raffinate water phase and a loaded organic phase through extraction treatment in step C), wherein the loaded organic phase is an organic phase containing impurities (iron, copper, aluminum), and may also contain a small amount of valuable metals (nickel, cobalt, manganese, lithium). Therefore, it is washed to further remove and recover the valuable metals therein.

[0078] In the present invention, the detergent used for the washing is preferably sulfuric acid. In the present invention, the concentration of the sulfuric acid is preferably 0.02-0.2 mol / L, specifically 0.02 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L. In the present invention, the volume ratio of the loaded organic phase to the detergent (i.e., O / A ratio) is preferably 10:1-50:1. In the present invention, there is no particular restriction on the temperature conditions for mixing the detergent with the loaded organic phase, and it can be carried out at room temperature, which can be 20-25°C, specifically 25°C. The above two can be mixed by stirring or shaking. Among them, the stirring and mixing rate is preferably 300-500 rpm, specifically 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm. The mixing time is preferably 5-30 min, specifically 5 min, 10 min, 15 min, 20 min, 25 min, 30 min.

[0079] In the present invention, the washing method is preferably countercurrent washing. The washing can be a single-stage washing or a multi-stage washing. The number of stages of the multi-stage washing is preferably 3 to 6. During the above-mentioned washing process, a small amount of valuable metals (nickel, cobalt, manganese, lithium) entrained in the loaded organic phase is washed from the organic phase into the detergent to form a washing residual liquid; and the organic phase after the valuable metals are removed becomes a washing organic phase. In actual operation, after the countercurrent washing, the phases are allowed to stand for phase separation, and the washing residual liquid and the washing organic phase are obtained respectively.

[0080] Stripping: Stripping the washed organic phase with a stripping agent to obtain a stripping solution and a blank organic phase.

[0081] After the washing treatment in the previous step, the valuable metals entrained in the organic phase have been further removed, and the obtained washed organic phase mainly contains impure metals (iron, copper, aluminum). The present invention further strips off the metals (iron, copper, aluminum) loaded in the organic phase by stripping.

[0082] In the present invention, the stripping agent is preferably a mixed solution of sulfuric acid and sodium sulfite. The concentration of the sulfuric acid used is preferably 0.5-2 mol / L, specifically 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L. The concentration of sodium sulfite in the mixed solution is preferably 0.01-1 mol / L, specifically 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1.0 mol / L.

[0083] In the present invention, the washing organic phase and the stripping agent are mixed in a certain ratio, and the volume ratio of the washing organic phase to the stripping agent (i.e., the O / A ratio) is preferably 3:1 to 10:1. In the present invention, there is no special restriction on the temperature conditions for mixing the washing organic phase with the stripping agent, and it can be carried out at room temperature, which can be 20 to 25°C, specifically 25°C. The above two can be mixed by stirring or shaking. Among them, the stirring and mixing rate is preferably 300 to 500rpm, specifically 300rpm, 350rpm, 400rpm, 450rpm, 500rpm. . The mixing time is preferably 5 to 30min, specifically 5min, 10min, 15min, 20min, 25min, 30min.

[0084] In the process of mixed stripping of the washed organic phase and the stripping agent, the iron, copper and aluminum in the washed organic phase are extracted into the stripping agent to form a stripping solution containing iron, copper and aluminum, and the organic phase after the iron, copper and aluminum are removed becomes a blank organic phase. Therefore, after stripping, a stripping solution and a blank organic phase are obtained respectively.

[0085] In the present invention, the stripping is preferably multi-stage cross-current stripping. The number of stages of the multi-stage cross-current stripping is preferably 4 to 6. After the cross-current stripping reaches equilibrium, the phases are separated by standing to obtain a stripping solution and a blank organic phase.

[0086] [About step DM]:

[0087] DM) stripping: stripping the loaded organic phase with a stripping agent to obtain a stripping solution and a blank organic phase.

[0088] In the present invention, in the stripping step DM), the stripping agent and the operating conditions are the same as those in the stripping step DN), except that the washing step is omitted and the washing organic phase is replaced by the loading organic phase compared to the step DN, which will not be described in detail here. For some embodiments, the washing step is omitted because the loss rate of nickel, cobalt, manganese and lithium in the previous extraction step is very low and there is no need to wash again.

[0089] The method provided by the present invention first mixes a certain extractant, a certain improver and a diluent to obtain an extraction solvent; then the extraction solvent is mixed with a saponifier for saponification to obtain a saponified extraction solvent; thereafter, the saponified extraction solvent and the waste battery leachate are mixed for extraction to obtain a raffinate aqueous phase and a loaded organic phase, respectively; finally, stripping is performed, or washing and stripping are performed to obtain a stripping solution and a blank organic phase, respectively. Compared with the prior art, the present invention simplifies the process, and can achieve the separation of impurities (aluminum, iron and copper) from other metal ions through a one-step selective co-extraction. Moreover, the extraction system of the present invention has good phase separation, effectively reduces heavy metal entrainment, reduces the loss rate of valuable metals (lithium, nickel, cobalt, manganese) during the impurity removal process, and improves the metal recovery rate. Moreover, the method of the present invention does not produce slag, and does not require waste slag treatment.

[0090] The experimental results show that the method of the present invention can extract more than 99.7% of Al, more than 99.7% of Cu, and 100% of Fe into the organic phase in the extraction stage, and the impurity removal effect is good. At the same time, the loss rate of nickel, cobalt, manganese and lithium in the process is less than 0.68%, which can effectively reduce the loss rate of valuable metals. In the stripping stage, the stripping rates of iron, copper and aluminum in the organic phase are all over 99.5%, which can effectively remove impurity metals.

[0091] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0092] Example 1

[0093] A) The extractant CA-12, the improver TBP and the diluent sulfonated kerosene are mixed to obtain an extraction solvent 1. In the obtained extraction solvent 1, the volume percentage concentration of the extractant is 30 vol%, and the volume percentage concentration of the improver is 20 vol%.

[0094] B) 250 mL of extraction solvent 1 and a certain volume of ammonia water (concentration 5 mol / L) were placed in a 500 mL separatory funnel and shaken at room temperature to make the saponification degree of extraction solvent 1 reach 25%, thereby obtaining saponified extraction solvent 1.

[0095] C) Extraction:

[0096] The pH value of the waste battery leachate (referred to as feed solution 1, whose composition is shown in Table 1) was adjusted to 2.5 using sodium hydroxide. Feed solution 1 was subjected to three-stage countercurrent extraction using saponification extraction solvent 1, with a phase ratio of O / A=1:1, a stirring speed of 500 rpm, stirring for 10 min at room temperature of 25°C, standing for 5 min, and separating the organic phase and the aqueous phase to obtain a loaded organic phase and a raffinate aqueous phase, respectively.

[0097] The components in the loaded organic phase and the raffinate phase were tested, and the results are shown in Table 1. The results show that 99.7% Al, 100% Cu and 100% Fe were extracted into the organic phase, and the loss of nickel, cobalt, manganese and lithium in the process was less than 0.6%.

[0098] D) Washing:

[0099] Take the loaded organic phase and detergent (0.02 mol / L sulfuric acid) at a ratio of O / A = 10:1 for single-stage extraction, with a stirring speed of 500 rpm, stirring at room temperature of 25°C for 5 min, standing for 5 min, separating the organic phase and the aqueous phase, and obtaining the washed organic phase and the washed residual liquid respectively.

[0100] The components in the washed organic phase were tested, and the results are shown in Table 1. The results show that most of the valuable metals in the loaded organic phase were washed and removed. Combined with the calculation of the component content in the washed organic phase, only 0.18% Ni, 0.09% Co and 0.06% Mn were lost in the washed organic phase, and the total loss rate of nickel, cobalt, manganese and lithium was only 0.33%.

[0101] E) Stripping:

[0102] Take the washed organic phase and the stripping agent (a mixed solution of sulfuric acid and sodium sulfite, the concentration of sulfuric acid used is 0.5 mol / L, and the concentration of sodium sulfite in the mixed solution is 0.02 mol / L) and perform four-stage continuous stripping at a phase ratio of O / A=3:1, with a stirring speed of 500 rpm, stirring at room temperature of 25°C for 5 min, standing for 5 min, separating the organic phase and the aqueous phase, and obtaining a blank organic phase and a stripping solution, respectively.

[0103] The components in the blank organic phase were tested, and the results showed that the contents of iron, copper and aluminum were all less than 2 mg / L. Combined with the solution volume, the stripping rates of iron, copper and aluminum in the organic phase were all over 99.9%.

[0104] Table 1: Liquid composition of each step of Example 1

[0105] Al Fe Cu Ni Co Mn Li Feed solution 1 (mg / L) 1336 641 1687 1640 13480 1981 4470 Raffinate water phase (mg / L) 4 0 0 1633 13412 1973 4464 Loaded organic phase (mg / L) 1333 640 1690 9 76 9 8 Washing organic phase (mg / L) 1322.2 640 1664.5 2.9 11.7 1.1 0

[0106] It can be seen from Table 1 that the contents of Cu, Fe and Al in the raffinate water phase obtained after extraction are low, and the impurity removal effect is obvious; the contents of Ni, Co and Mn in the washed organic phase are low, indicating that the loss of nickel, cobalt and manganese is small during the impurity removal process and the economic benefit is high.

[0107] Example 2

[0108] A) The extractant CA-12, the improver TBP and the diluent sulfonated kerosene were mixed to obtain an extraction solvent 2. In the obtained extraction solvent 2, the volume percentage concentration of the extractant was 35 vol%, and the volume percentage concentration of the improver was 15 vol%.

[0109] B) 250 mL of extraction solvent 2 and a certain volume of ammonia water (concentration 5 mol / L) were placed in a 500 mL separatory funnel and shaken at room temperature to make the saponification degree of extraction solvent 2 reach 40%, thereby obtaining saponified extraction solvent 2.

[0110] C) Extraction:

[0111] The pH value of the waste battery leachate (referred to as feed solution 2, whose composition is shown in Table 2) was adjusted to 2.0 using aqueous ammonia. Feed solution 2 was subjected to four-stage countercurrent extraction using saponification extraction solvent 2, with a phase ratio of O / A=1:1, a stirring speed of 500 rpm, stirring for 10 min at room temperature of 25°C, standing for 5 min, and separating the organic phase and the aqueous phase to obtain a loaded organic phase and a raffinate aqueous phase, respectively.

[0112] The components in the loaded organic phase and the raffinate phase were tested, and the results are shown in Table 2. The results show that 99.9% Al, 100% Cu and 100% Fe were extracted into the organic phase, and the total loss of nickel, cobalt, manganese and lithium in the process was 0.6% (Ni loss rate was 0.16%, Co loss rate was 0.11%, Mn loss rate was 0.16%, and Li loss rate was 0.17%).

[0113] E) Stripping:

[0114] Take the loaded organic phase and the stripping agent (a mixture of sulfuric acid and sodium sulfite, the concentration of sulfuric acid used is 1 mol / L, and the concentration of sodium sulfite in the mixture is 0.01 mol / L) and perform four-stage continuous stripping at a phase ratio of O / A=5:1, with a stirring speed of 500 rpm, stirring at room temperature of 25°C for 5 min, standing for 5 min, separating the organic phase and the aqueous phase, and obtaining a blank organic phase and a stripping solution, respectively.

[0115] The components in the blank organic phase were tested, and the results showed that the contents of iron, copper and aluminum were all less than 3 mg / L. Combined with the solution volume, the stripping rates of iron, copper and aluminum in the organic phase were all over 99.8%.

[0116] Table 2: Liquid composition of each step in Example 2

[0117] Al Fe Cu Ni Co Mn Li Feed liquid 2 (mg / L) 2600 150 2300 14930 7190 11450 5330 Raffinate water phase (mg / L) 3 0 1 14906 7182 11422 5321 Loaded organic phase (mg / L) 2597 150 2299 24 8 18 9

[0118] It can be seen from Table 2 that the contents of Cu, Fe and Al in the raffinate water phase obtained after extraction are low, and the impurity removal effect is obvious; the contents of Ni, Co and Mn in the loaded organic phase are low, indicating that the loss of nickel, cobalt and manganese is small during the impurity removal process and the economic benefit is high.

[0119] Example 3

[0120] A) The extractant CA-12, the improver TBP and the diluent sulfonated kerosene were mixed to obtain an extraction solvent 3. In the obtained extraction solvent 3, the volume percentage concentration of the extractant was 30 vol%, and the volume percentage concentration of the improver was 20 vol%.

[0121] B) 250 mL of extraction solvent 3 and a certain volume of ammonia water (concentration 5 mol / L) were placed in a 500 mL separatory funnel and shaken at room temperature to make the saponification degree of extraction solvent 3 reach 40%, thereby obtaining saponified extraction solvent 3.

[0122] C) Extraction:

[0123] The pH value of the waste battery leachate (referred to as feed solution 3, whose composition is shown in Table 3) was adjusted to 2.0 using sodium hydroxide. The feed solution 3 was subjected to five-stage countercurrent extraction using saponification extraction solvent 3, with a phase ratio of O / A=1.3:1, a stirring speed of 500 rpm, stirring for 10 min at room temperature of 25°C, standing for 5 min, and separating the organic phase and the aqueous phase to obtain a loaded organic phase and a raffinate aqueous phase, respectively.

[0124] The components in the loaded organic phase and the raffinate phase were tested, and the results are shown in Table 3. The results show that 99.9% Al, 99.7% Cu and 100% Fe were extracted into the organic phase, and the loss of nickel, cobalt, manganese and lithium in the process was 0.68% (Ni loss rate was 0.21%, Co loss rate was 0.21%, Mn loss rate was 0.14%, and Li loss rate was 0.12%).

[0125] E) Stripping:

[0126] Take the loaded organic phase and the stripping agent (a mixture of sulfuric acid and sodium sulfite, the concentration of sulfuric acid used is 0.9 mol / L, and the concentration of sodium sulfite in the mixture is 0.05 mol / L) and perform five-stage continuous stripping at a phase ratio of O / A=5:1, with a stirring speed of 500 rpm, stirring at room temperature of 25°C for 5 min, standing for 5 min, separating the organic phase and the aqueous phase, and obtaining a blank organic phase and a stripping solution, respectively.

[0127] The components in the blank organic phase were tested, and the results showed that the contents of iron, copper and aluminum were all less than 5 mg / L. Combined with the solution volume, the stripping rates of iron, copper and aluminum in the organic phase were all over 99.5%.

[0128] Table 3: Liquid composition of each step of Example 3

[0129] Al Fe Cu Ni Co Mn Li Feed liquid 3 (mg / L) 2620 1300 3030 37000 18750 16480 10500 Raffinate water phase (mg / L) 3 0 9 36920 18711 16457 10478 Loaded organic phase (mg / L) 2013 1000 2324 61 30 18 10

[0130] It can be seen from Table 3 that the contents of Cu, Fe and Al in the raffinate water phase obtained after extraction are low, and the impurity removal effect is obvious; the contents of Ni, Co and Mn in the loaded organic phase are low, indicating that the loss of nickel, cobalt and manganese is small during the impurity removal process and the economic benefit is high.

[0131] Comparative Example 1

[0132] The process was carried out in accordance with Example 3, except that the extractant CA-12 in step A) was replaced by the extractant cyclohexane acid, and the improver TBP was replaced by octanol.

[0133] The composition of the feed solution in each step is shown in Table 4:

[0134] Table 4: Comparative Example 1 Feed Liquid Composition in Each Step

[0135] Al Fe Cu Ni Co Mn Li Feed liquid 3 (mg / L) 2620 1300 3030 37000 18750 16480 10500 Raffinate water phase (mg / L) 202 0 157 36853 18661 16406 10470 Loaded organic phase (mg / L) 1860 1000 2210 113 68 57 23

[0136] It can be seen from Table 4 that the content of Cu, Fe and Al in the raffinate aqueous phase obtained after extraction is still relatively high. Combined with the solution volume calculation, only 92.3% Al, 94.8% Cu and 100% Fe are extracted into the organic phase. The total loss of nickel, cobalt, manganese and lithium in this process is greater than 1.6%, and the impurity removal effect is poor. The content of Ni, Co and Mn in the loaded organic phase is relatively high, indicating that the loss rate of nickel, cobalt and manganese is high during the impurity removal process, and the economic benefit is poor. It can be seen that the method of the present invention uses a certain extractant + modifier to work together, which can improve the selectivity for iron, copper and aluminum metals, which is beneficial to improving the impurity removal effect.

[0137] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for removing copper, iron and aluminum from waste battery leachate by co-extraction, characterized in that: The following steps are involved: A) mixing an extractant, a modifier and a diluent to obtain an extraction solvent; Wherein, the extractant is secondary octylphenoxy substituted acetic acid; The improver is tributyl phosphate and / or isooctyl alcohol; B) mixing the extraction solvent with a saponifying agent to saponify the mixture to obtain a saponified extraction solvent; C) Extraction: Mixing the saponification extraction solvent and the waste battery leachate for extraction to obtain a raffinate water phase and a loaded organic phase respectively; D) comprising step DM) stripping, or step DN) washing and stripping; DM) Stripping: The loaded organic phase is stripped using a stripping agent to obtain a stripping solution and a blank organic phase respectively; DN) Washing and stripping: Washing: washing the loaded organic phase to obtain a washing residue and a washing organic phase; Stripping: Stripping the washed organic phase with a stripping agent to obtain a stripping solution and a blank organic phase.

2. The method according to claim 1, characterized in that In step A), the volume percentage concentration of the extractant in the obtained extraction solvent is 10% to 40%, and the volume percentage concentration of the improver is 5% to 20%.

3. The method according to claim 1, characterized in that In step B), the saponifying agent is at least one of ammonia water, sodium hydroxide, sodium carbonate and ammonium carbonate.

4. The method according to claim 1, characterized in that: In step B), the saponification degree of the saponification extraction solvent is 10% to 40%.

5. The method according to claim 1, characterized in that In step B), the volume ratio of the saponification extraction solvent to the waste battery leaching solution is 3:1 to 1:

5.

6. The method according to claim 1, characterized in that In step C), before the extraction, the pH value of the waste battery leachate is adjusted; The pH value is adjusted to a value between 1.5 and 2.

5.

7. The method according to claim 1, characterized in that In step DN), the washing agent used in the washing is sulfuric acid; The concentration of the sulfuric acid is 0.02-0.2 mol / L.

8. The method according to claim 1, characterized in that: In step DN), the volume ratio of the washed organic phase to the stripping agent is 3:1 to 10:

1.

9. The method according to claim 1, characterized in that: In step DM), the volume ratio of the loaded organic phase to the stripping agent is 3:1 to 10:

1.

10. The method according to claim 1, characterized in that In step C), the extraction is countercurrent extraction; the extraction is single-stage extraction or multi-stage extraction; wherein the number of stages of the multi-stage extraction is preferably 3 to 6; In step DN), the washing is countercurrent washing; the washing is single-stage washing or multi-stage washing; wherein the number of stages of the multi-stage washing is 3 to 6; In step DN), the stripping is multi-stage cross-current stripping; the number of stages of the multi-stage cross-current stripping is 4 to 6; In step DM), the stripping is multi-stage cross-current stripping; the number of stages of the multi-stage cross-current stripping is 4 to 6.

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