Method for recovering valuable metals from lithium-battery black powder

Abstract

The present application relates to the technical field of lithium batteries. Disclosed is a method for recovering valuable metals from a lithium-battery black powder. The method comprises: adding a sulfur-containing substance and an inhibitor to the lithium-battery black powder; then performing roasting, water leaching, and filtration so as to obtain a first filtrate and a first filter residue; and preparing a lithium salt from the obtained first filtrate, and recovering other valuable metals from the first filter residue, wherein the inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide. By means of the method provided in the present application, valuable metals in various lithium-battery black powders are recovered, such that while ensuring a higher lithium recovery rate (≥98%), additional valuable metals can enter the residue phase (loss rate <2%) for subsequent recovery, thereby improving the recovery rate of other valuable metals.

Description

Method for Recycling Valuable Metals from Black Powder of Lithium Batteries

[0001] Cross - reference

[0002] This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, with the application number 202411755308.7, the filing date of December 03, 2024, and the invention title "Method for Recycling Valuable Metals from Black Powder of Lithium Batteries". The entire content of this application is incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of lithium batteries, and particularly to a method for recycling valuable metals from black powder of lithium batteries. Background Art

[0004] With the rapid development of fields such as electric vehicles and energy storage systems, higher requirements are put forward for the energy density, cycle life, safety performance, etc. of lithium batteries. As a key component of the battery, the cathode material of lithium batteries has an important impact on the performance of lithium batteries.

[0005] Recycling lithium batteries has the dual attributes of saving metal resources and environmental protection. Traditional hydrometallurgy leaches out all valuable metals, then removes impurities, precipitates nickel, cobalt, and manganese, and finally recovers lithium. When precipitating nickel, cobalt, and manganese, lithium will inevitably be lost, resulting in a low recovery rate of lithium. When recycling through traditional pyrometallurgy, lithium remains in the flue dust and needs to be collected for secondary treatment. The recovery efficiency of traditional hydrometallurgy and pyrometallurgy for other valuable metals is also very low.

[0006] CN108832215A discloses a method for selectively recycling the cathode material of lithium - ion batteries, which belongs to a typical combination of hydrometallurgy and pyrometallurgy. This patent uses sulfuric acid or sulfate to uniformly mix with the cathode material of lithium batteries, then conducts roasting and water leaching. The lithium element is transferred to the aqueous solution in the form of water - soluble lithium sulfate, and most metal elements such as nickel and cobalt exist in the slag phase as oxides insoluble in water, and the lithium element is selectively extracted.

[0007] CN117416973A discloses a selective lithium extraction process for lithium iron phosphate batteries. The cathode powder of waste LiMn 1-x Fe x PO4 batteries is sulfuric - acid acidified with H2SO4, then crushed, roasted, and washed with water to obtain a lithium - rich solution. The lithium - rich solution is adjusted with LiOH solution to remove impurities, then sulfur is supplemented to the purified solution after impurity removal, and finally the sulfur - supplemented solution is evaporated and crystallized to obtain Li2SO4. The advantage of this patent is a high recovery rate of lithium elements, but the process is long, repeatedly adjusting the pH value and secondary acid supplementation consume a large amount of acid - base reagents.

[0008] In existing methods for recovering lithium battery black powder, some nickel, cobalt, manganese, and iron elements form water-soluble nickel sulfate, cobalt sulfate, or ferrous sulfate, which enter the leaching solution along with the lithium elements, requiring further impurity removal. This valuable metal exists as solid waste, resulting in a loss.

[0009] Therefore, there is an urgent need to develop a method for efficiently recovering valuable metals from various lithium battery black powders. Summary of the Invention

[0010] The purpose of this application is to overcome the problems existing in the prior art and provide a method for recovering valuable metals from lithium battery black powder.

[0011] To achieve the above objectives, this application provides a method for recovering valuable metals from lithium battery black powder, wherein the method includes the following steps:

[0012] (1) After adding sulfur-containing substances and inhibitors to lithium battery black powder, the mixture is roasted, soaked in water, and filtered to obtain the first filtrate and the first filter residue.

[0013] (2) Prepare lithium salt from the first filtrate obtained in step (1) and recover other valuable metals from the first filter residue;

[0014] The inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide.

[0015] The molar ratio of other valuable metals in the lithium battery black powder to the metal elements contained in the inhibitor is 1:0.05-0.5.

[0016] The beneficial technical effects achieved by this application through the above technical solution are as follows:

[0017] (1) The method provided in this application can be used to recover valuable metals from various lithium battery black powders. While ensuring a high lithium recovery rate (≥98%), it can also allow more other valuable metals to enter the slag phase (loss rate <2%) for subsequent recovery, thereby improving the recovery rate of other valuable metals.

[0018] (2) This application can reduce the amount of sulfur-containing substances added during roasting, thereby enabling efficient recovery of lithium. Attached Figure Description

[0019] Figure 1 is a process flow diagram of this application. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of this application provides a method for recovering valuable metals from lithium battery black powder, wherein the method includes the following steps:

[0022] (1) After adding sulfur-containing substances and inhibitors to lithium battery black powder, the mixture is roasted, soaked in water, and filtered to obtain the first filtrate and the first filter residue.

[0023] (2) Prepare lithium salt from the first filtrate obtained in step (1) and recover other valuable metals from the first filter residue;

[0024] The inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide.

[0025] The molar ratio of other valuable metals in the lithium battery black powder to the metal elements contained in the inhibitor is 1:0.05-0.5.

[0026] Current technology typically involves adding alkaline substances to the leachate after roasting and leaching to precipitate valuable metals other than lithium as impurities, thereby improving the purity of recovered lithium. However, during the impurity removal process, some lithium is inevitably carried into the precipitate, resulting in lithium loss. Furthermore, this precipitate, as impurity removal residue, is usually treated as solid waste, leading to the loss of other valuable metals.

[0027] Although CN108832215A decomposes most transition metal sulfates (such as cobalt sulfate) into metal oxides and enters the solid slag for subsequent recovery by controlling reaction conditions, a portion (about 5-8%) of the transition metal sulfates will still be incompletely converted. This portion of transition metal sulfates will still enter the aqueous solution along with lithium during leaching (after impurity removal, it is generally not recovered), resulting in the loss of valuable metals (such as nickel, cobalt, manganese, and iron) during the recovery of solid slag.

[0028] This application improves the efficiency of subsequent valuable metal recovery processes by adding specific inhibitors before roasting, so that valuable metals that would otherwise be unable to enter the solid slag and would be leached into the leachate remain in oxide form and do not participate in leaching, thereby entering the solid slag.

[0029] In this application, the amount of inhibitor added is based on the metal elements contained therein. If too little inhibitor is added, other valuable metals will be lost significantly; if too much inhibitor is added, it will hinder the subsequent recovery of other valuable metals from the first filter residue.

[0030] In some embodiments of this application, the lithium battery black powder is selected from at least one of ternary lithium battery (NCM) black powder, lithium cobalt oxide battery (LCO) black powder, lithium nickel oxide battery (LNO) black powder, lithium manganese oxide battery (LMO) black powder, lithium iron phosphate battery (LFP) black powder, and lithium manganese iron phosphate battery (LMFP) black powder. This application is effective not only for a single type of lithium battery black powder, but also for mixtures of multiple lithium battery black powders.

[0031] The "black powder" mentioned in this application can be positive electrode black powder or a mixture of positive and negative electrode black powder.

[0032] In some embodiments of this application, the sulfur-containing substance is selected from at least one of sulfuric acid, ammonium sulfate, nickel sulfate, nickel sulfite, cobalt sulfate, cobalt sulfite, manganese sulfate, manganese sulfite, sodium sulfate, sodium sulfite, potassium sulfate, potassium sulfite, copper sulfate, copper sulfite, and ferrous sulfate.

[0033] In some embodiments of this application, the inhibitor is selected from at least one of magnesium oxide, aluminum oxide, and calcium hydroxide.

[0034] In some embodiments of this application, the other valuable metal is selected from at least one of nickel, cobalt, manganese, and iron.

[0035] In some embodiments of this application, the molar ratio of other valuable metals in the lithium battery black powder to the metal elements contained in the inhibitor is 1:0.05-0.2, preferably 1:0.05-0.1. In some embodiments of this application, when the lithium battery black powder includes a first black powder and a second black powder, the sulfur-containing substance includes at least one of sulfuric acid, copper sulfate, and ferrous sulfate, and ammonium sulfate; wherein, the first black powder is at least one of ternary lithium battery black powder, lithium cobalt oxide battery black powder, lithium nickel oxide battery black powder, and lithium manganese oxide battery black powder, and the second black powder is at least one of lithium iron phosphate battery black powder and lithium manganese iron phosphate battery black powder.

[0036] In this application, sulfuric acid is used to recover valuable metals from the first black powder, and ammonium sulfate is used to recover valuable metals from the second black powder. This reduces the amount of sulfur-containing substances used and achieves efficient lithium extraction.

[0037] In practice, if the content of molecules (lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide) in the first black powder and the content of molecules (lithium iron phosphate, lithium manganese iron phosphate) in the second black powder cannot be known, it can be calculated by detecting the content of each valuable metal element.

[0038] In some embodiments of this application, the mass concentration of the sulfuric acid is 70-100%, preferably 80-98%.

[0039] In some embodiments of this application, the average particle size of the ammonium sulfate is 74-245 μm, preferably 83-165 μm.

[0040] In some embodiments of this application, the molar ratio of lithium in the first black powder to the total sulfur content of at least one of sulfuric acid, copper sulfate, and ferrous sulfate is 1:0.5-1, preferably 1:0.52-0.6, and more preferably 1:0.55-0.6. In this application, if the total sulfur content of at least one of sulfuric acid, copper sulfate, and ferrous sulfate is too high, more nickel, cobalt, manganese, and iron will be leached out during water leaching, resulting in greater losses of other valuable metals; if the total sulfur content is too low, the reaction will be incomplete, and the lithium leaching rate will be low.

[0041] In some embodiments of this application, the molar ratio of lithium to ammonium sulfate in the second black powder is 1:0.55-1, preferably 1:0.55-0.65, and more preferably 1:0.55-0.6. In this application, if the amount of ammonium sulfate is too large, a small portion of the excess ammonium sulfate will react with the first black powder, causing nickel, cobalt, manganese, and iron to form sulfates, resulting in significant leaching losses; if the amount of ammonium sulfate is too small, the reaction will be incomplete, and the lithium leaching rate will be low.

[0042] In some embodiments of this application, the roasting includes primary roasting and / or secondary roasting.

[0043] In some embodiments of this application, the temperature of the first calcination is 280-350°C, preferably 280-300°C.

[0044] In some embodiments of this application, the roasting time is 0.5-4 hours, preferably 1-2 hours.

[0045] In some embodiments of this application, the temperature of the secondary calcination is 500-800℃, preferably 550-700℃.

[0046] In some embodiments of this application, the secondary roasting time is 1-12 hours, preferably 3-4 hours.

[0047] When the lithium battery black powder is only the first black powder, sulfuric acid is used as the sulfur-containing substance, and the above-mentioned secondary roasting conditions are used for roasting; when the lithium battery black powder is only the second black powder, ammonium sulfate is used as the sulfur-containing substance, and the above-mentioned primary roasting conditions are used for roasting.

[0048] When the lithium battery black powder includes a first black powder and a second black powder; wherein the first black powder is at least one of ternary lithium battery black powder, lithium cobalt oxide battery black powder, lithium nickel oxide battery black powder and lithium manganese oxide battery black powder, and the second black powder is at least one of lithium iron phosphate battery black powder and lithium manganese iron phosphate battery black powder, the baking is carried out under the conditions of primary baking and secondary baking in sequence.

[0049] In this application, by further defining the conditions for primary and secondary roasting, a higher lithium yield can be obtained with less sulfur-containing material, which will also affect the amount of other valuable metals enriched in the first filter residue.

[0050] When the lithium battery black powder is only the first black powder, sulfuric acid is used as the sulfur-containing substance, and the above-mentioned secondary roasting conditions are used for roasting; when the lithium battery black powder is only the second black powder, ammonium sulfate is used as the sulfur-containing substance, and the above-mentioned primary roasting conditions are used for roasting.

[0051] In some embodiments of this application, the liquid-to-solid ratio of the water immersion is 1.5-10:1, preferably 2-4:1.

[0052] In some embodiments of this application, the immersion time is 0.5-12 hours, preferably 1-4 hours.

[0053] In some embodiments of this application, ammonia is added to the first filtrate to obtain a second filtrate and a second filter residue. The purpose of adding ammonia is to remove metal elements from the added inhibitor.

[0054] In some embodiments of this application, the concentration of ammonia water is 5-30%, preferably 15-25%.

[0055] In some embodiments of this application, ammonia is added to the first filtrate until the pH is greater than 11.

[0056] In some embodiments of this application, the second filtrate is evaporated and calcined to obtain refined lithium sulfate. After evaporation, crude lithium sulfate is obtained, which is then purified by calcination to obtain refined lithium sulfate.

[0057] In some embodiments of this application, the calcination temperature is 500-600°C, preferably 550°C.

[0058] The present application will be described in detail below through examples.

[0059] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0060] In the following examples and comparative examples, the molecules in the first black powder are LiNi. x Co y Mn z O2 (x+y+z=1, hereinafter referred to as the first molecule), the molecules in the second black powder are LiFePO4 or LiMn. a Fe b PO4 (a+b=1, hereinafter referred to as the second molecule).

[0061] Example 1

[0062] This embodiment illustrates a method for recovering valuable metals when the lithium battery black powder is a mixture of a first black powder and a second black powder. See Figure 1.

[0063] Upon testing, the content of valuable metal elements in the black powder used in this embodiment is as follows:

[0064] Table 1.1 Content of Valuable Metal Elements in Black Powder

[0065] Calculations show that the content of the first molecule in the black powder is 77% (relative to the cathode material), and the content of the second molecule is 23% (relative to the cathode material).

[0066] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to the lithium battery black powder and mix them evenly; the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.55, and the sulfuric acid concentration is 98%; the molar ratio of lithium to ammonium sulfate in the second molecule is 1:0.55, and the average particle size of ammonium sulfate is 165μm; the molar ratio of the total amount of nickel, cobalt, manganese, and iron in the black powder to the molar ratio of magnesium in magnesium oxide is 1:0.05;

[0067] (2) The black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide is roasted at 280°C for 1 hour to obtain a single roasted black powder;

[0068] (3) The first-calcined black powder is calcined again at 600℃ for 3 hours to obtain the second-calcined black powder;

[0069] (4) The secondary roasted black powder was leached with water at room temperature and filtered to obtain filtrate 1 and filter residue 1; filter residue 1 is a nickel-cobalt-manganese-iron concentrate, which can be used for subsequent recovery of nickel-cobalt-manganese-iron; the leaching liquid-to-solid ratio was 4:1, and the leaching time was 1 hour; the element leaching rate in filtrate 1 is shown in Table 1.2:

[0070] Table 1.2, Element Leaching Rate

[0071] (5) Add ammonia water (concentration of 20%) to filtrate 1, stir, and stop adding when the pH value is >11 and no longer changes. Filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue.

[0072] (6) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0073] (7) The crude ammonium sulfate crystals were calcined at 550°C to remove ammonium sulfate and water of crystallization, and refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0074] Example 2

[0075] This embodiment illustrates a method for recovering valuable metals when the lithium battery black powder is a mixture of a first black powder and a second black powder.

[0076] Upon testing, the content of valuable metal elements in the black powder used in this embodiment is as follows:

[0077] Table 2.1 Content of Valuable Metal Elements in Black Powder

[0078] Calculations show that the content of the first molecule in the black powder is 47% (relative to the cathode material), and the content of the second molecule is 53% (relative to the cathode material).

[0079] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to lithium battery black powder and mix them evenly; the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.6, and the sulfuric acid concentration is 80%; the molar ratio of lithium to ammonium sulfate in the second molecule is 1:0.55, and the average particle size of ammonium sulfate is 198μm; the molar ratio of the total amount of nickel, cobalt, manganese, and iron in the black powder to the molar ratio of magnesium in magnesium oxide is 1:0.1;

[0080] (2) The black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide is roasted at 300°C for 2 hours to obtain a single roasted black powder;

[0081] (3) The first-calcined black powder is calcined again at 570℃ for 3 hours to obtain the second-calcined black powder;

[0082] (4) The secondary roasted black powder was leached with water at room temperature and filtered to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel-cobalt-manganese-iron enrichment, which can be used for subsequent recovery of nickel-cobalt-manganese-iron; the leaching solution-solid ratio was 2:1, and the leaching time was 2 hours; the element leaching rate in filtrate 1 is shown in Table 2.2:

[0083] Table 2.2, Element Leaching Rate

[0084] (5) Add ammonia water (concentration of 15%) to filtrate 1, stir, and stop adding when the pH value is >11 and no longer changes. Filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue.

[0085] (6) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0086] (7) The crude ammonium sulfate crystals were calcined at 550°C to remove ammonium sulfate and water of crystallization, and refined lithium sulfate with a purity of 99.6% and a lithium yield of 98.5%.

[0087] Example 3

[0088] This embodiment illustrates a method for recovering valuable metals when the lithium battery black powder is a mixture of a first black powder and a second black powder.

[0089] Upon testing, the content of valuable metal elements in the black powder used in this embodiment is as follows:

[0090] Table 3.1 Content of Valuable Metal Elements in Black Powder

[0091] Calculations show that the content of the first molecule in the black powder is 14% (relative to the cathode material), and the content of the second molecule is 86% (relative to the cathode material).

[0092] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to lithium battery black powder and mix them evenly; the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.52, and the sulfuric acid concentration is 90%; the molar ratio of lithium to ammonium sulfate in the second molecule is 1:0.6, and the average particle size of ammonium sulfate is 150μm; the molar ratio of the total amount of nickel, cobalt, manganese, and iron in the black powder to the molar ratio of magnesium in magnesium oxide is 1:0.5;

[0093] (2) The black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide was roasted at 290°C for 2 hours to obtain the first roasted black powder;

[0094] (3) The first-calcined black powder is calcined again at 550℃ for 3 hours to obtain the second-calcined black powder;

[0095] (4) The secondary roasted black powder was leached with water at room temperature and filtered to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel-cobalt-manganese-iron enrichment, which can be used for subsequent recovery of nickel-cobalt-manganese-iron; the leaching liquid-to-solid ratio was 3:1, and the leaching time was 1 hour; the element leaching rate in filtrate 1 is shown in Table 3.2:

[0096] Table 3.2, Element Leaching Rate

[0097] (5) Add ammonia water (concentration of 20%) to filtrate 1, stir, and stop adding when the pH value is >11 and no longer changes. Filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue.

[0098] (6) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0099] (7) The crude ammonium sulfate crystals were calcined at 550°C to remove ammonium sulfate and water of crystallization, and refined lithium sulfate with a purity of 99.6% and a lithium yield of 98.3%.

[0100] Example 4

[0101] This embodiment illustrates a method for recovering valuable metals when the lithium battery black powder is the first type of black powder.

[0102] Upon testing, the content of valuable metal elements in the black powder used in this embodiment is as follows:

[0103] Table 4.1 Content of Valuable Metal Elements in Black Powder

[0104] (1) Add sulfuric acid and magnesium oxide to lithium battery black powder and mix evenly; the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.52, and the sulfuric acid concentration is 98%; the molar ratio of the total amount of nickel, cobalt and manganese in the black powder to the amount of magnesium in magnesium oxide is 1:0.05;

[0105] (2) The black powder mixed with sulfuric acid and magnesium oxide was roasted at 600°C for 3 hours to obtain roasted black powder;

[0106] (3) The roasted black powder was leached with water at room temperature and filtered to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel-cobalt-manganese enrichment, which can be used for subsequent recovery of nickel-cobalt-manganese; the leaching liquid-to-solid ratio was 4:1, and the leaching time was 1 hour; the element leaching rate in filtrate 1 is shown in Table 4.2:

[0107] Table 4.2, Element Leaching Rate

[0108] (4) Add ammonia water (concentration of 20%) to filtrate 1, stir, and stop adding when the pH value is >11 and no longer changes. Filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue.

[0109] (5) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0110] (6) The crude ammonium sulfate crystals were calcined at 550°C to remove ammonium sulfate and water of crystallization, and refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0111] Example 5

[0112] This embodiment illustrates a method for recovering valuable metals when the lithium battery black powder is the second type of black powder.

[0113] Upon testing, the content of valuable metal elements in the black powder used in this embodiment is as follows:

[0114] Table 5.1 Content of Valuable Metal Elements in Black Powder

[0115] (1) Add ammonium sulfate and magnesium oxide to lithium battery black powder and mix evenly; the molar ratio of lithium to ammonium sulfate in the second molecule is 1:0.65, and the average particle size of ammonium sulfate is 165μm; the molar ratio of the total amount of manganese and iron in the black powder to the amount of magnesium in magnesium oxide is 1:0.05.

[0116] (2) The black powder mixed with ammonium sulfate and magnesium oxide was calcined at 280°C for 1 hour to obtain calcined black powder;

[0117] (3) The roasted black powder was leached with water at room temperature and filtered to obtain filtrate 1 and filter residue 1; filter residue 1 is a nickel-cobalt-manganese-iron concentrate, which can be used for subsequent recovery of nickel-cobalt-manganese-iron; the leaching solution-solid ratio was 4:1, and the leaching time was 1 hour; the element leaching rate in filtrate 1 is shown in Table 5.2:

[0118] Table 5.2, Element Leaching Rate

[0119] (4) Add ammonia water (concentration of 20%) to filtrate 1, stir, and stop adding when the pH value is >11 and no longer changes. Filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue.

[0120] (5) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0121] (6) The crude ammonium sulfate crystals were calcined at 550°C to remove ammonium sulfate and water of crystallization, and refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0122] Example 6

[0123] Valuable metals were recovered using the method described in Example 1, except that the molar ratio of the total amount of nickel, cobalt, manganese, and iron in the black powder to the amount of magnesium in the magnesium oxide was 1:0.04. The element leaching rates in filtrate 1 are shown in Table 6.1.

[0124] Table 6.1, Element Leaching Rate

[0125] The purified lithium sulfate obtained had a purity of 99.6% and a lithium yield of 96.3%.

[0126] Example 7

[0127] Valuable metals were recovered using the method described in Example 1, except that the molar ratio of the total nickel, cobalt, manganese, and iron in the black powder to the magnesium in the magnesium oxide was 1:0.6. The element leaching rates in filtrate 1 are shown in Table 7.1.

[0128] Table 7.1, Element Leaching Rate

[0129] The obtained refined lithium sulfate had a purity of 99.5% and a lithium yield of 98.5%.

[0130] Example 8

[0131] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:0.5. The element leaching rates in filtrate 1 are shown in Table 8.1.

[0132] Table 8.1, Element Leaching Rate

[0133] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 98.6%.

[0134] Example 9

[0135] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:1. The element leaching rates in filtrate 1 are shown in Table 9.1.

[0136] Table 9.1, Element Leaching Rate

[0137] The obtained refined lithium sulfate had a purity of 99.6% and a lithium yield of 98.8%.

[0138] Example 10

[0139] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:0.4. The element leaching rates in filtrate 1 are shown in Table 10.1.

[0140] Table 10.1, Element Leaching Rate

[0141] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 82.4%.

[0142] Example 11

[0143] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:1.1. The element leaching rates in filtrate 1 are shown in Table 11.1.

[0144] Table 11.1, Element Leaching Rate

[0145] The purified lithium sulfate obtained had a purity of 99.6% and a lithium yield of 98.0%.

[0146] Example 12

[0147] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:1. The element leaching rates in filtrate 1 are shown in Table 12.1.

[0148] Table 12.1, Element Leaching Rate

[0149] Refined lithium sulfate with a purity of 99.8% and a lithium yield of 98.8% was obtained.

[0150] Example 13

[0151] The method of Example 2 was used to recover valuable metals, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:0.3. The element leaching rates in filtrate 1 are shown in Table 13.1.

[0152] Table 13.1, Element Leaching Rate

[0153] The purified lithium sulfate obtained had a purity of 99.6% and a lithium yield of 86.9%.

[0154] Example 14

[0155] Valuable metals were recovered using the method described in Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:1.2; the element leaching rates in filtrate 1 are shown in Table 14.1.

[0156] Table 14.1, Element Leaching Rate

[0157] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 96.8%.

[0158] Example 15

[0159] The method of Example 3 was used to recover valuable metals, except that the initial roasting temperature was 260°C.

[0160] The element leaching rates in filtrate 1 are shown in Table 15.1:

[0161] Table 15.1, Element Leaching Rate

[0162] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 82.7%.

[0163] Example 16

[0164] The method of Example 3 was used to recover valuable metals, except that the primary roasting temperature was 360°C.

[0165] The element leaching rates in filtrate 1 are shown in Table 16.1:

[0166] Table 16.1, Element Leaching Rate

[0167] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 92.3%.

[0168] Example 17

[0169] The method of Example 3 was used to recover valuable metals, except that the secondary roasting temperature was 480°C.

[0170] The element leaching rates in filtrate 1 are shown in Table 17.1:

[0171] Table 17.1, Element Leaching Rate

[0172] The purified lithium sulfate obtained had a purity of 99.6% and a lithium yield of 64.3%.

[0173] Example 18

[0174] Valuable metals were recovered using the method described in Example 3, except that the secondary roasting temperature was 850°C. The element leaching rates in the resulting filtrate 1 are shown in Table 18.1.

[0175] Table 18.1, Element Leaching Rate

[0176] The purified lithium sulfate obtained had a purity of 99.7% and a lithium yield of 78.2%.

[0177] Example 19

[0178] The method of Example 1 was used to recover valuable metals, except that sulfuric acid was replaced with an equimolar amount of ammonium sulfate. The element leaching rates in the resulting filtrate 1 are shown in Table 19.1.

[0179] Table 19.1, Element Leaching Rate

[0180] Refined lithium sulfate with a purity of 99.7% and a lithium yield of 82.1% was obtained.

[0181] Example 20

[0182] The method for recovering valuable metals was followed in Example 1, except that ammonium sulfate was replaced with an equimolar amount of sulfuric acid. The element leaching rates in the resulting filtrate 1 are shown in Table 20.1.

[0183] Table 20.1, Element Leaching Rate

[0184] Refined lithium sulfate with a purity of 99.6% and a lithium yield of 82.9% was obtained.

[0185] Example 21

[0186] The method of Example 1 was used to recover valuable metals, except that magnesium oxide was replaced with an equimolar amount (based on metal element) of calcium hydroxide. The element leaching rates in the resulting filtrate 1 are shown in Table 21.1.

[0187] Table 21.1, Element Leaching Rate

[0188] Refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.2% was obtained. Calcium hydroxide inhibited the leaching of nickel, cobalt, manganese, and iron, causing them to transfer to filter residue 1.

[0189] Example 22

[0190] The method of Example 1 was used to recover valuable metals, except that magnesium oxide was replaced with an equimolar amount (based on metal element) of aluminum oxide. The element leaching rates in the resulting filtrate 1 are shown in Table 22.1.

[0191] Table 22.1, Element Leaching Rate

[0192] Refined lithium sulfate with a purity of 99.5% and a lithium yield of 99.1% was obtained. Alumina inhibited the leaching of nickel, cobalt, manganese, and iron, causing them to transfer to filter residue 1.

[0193] Comparative Example 1

[0194] Valuable metals were recovered using the method described in Example 1, except that magnesium oxide was not added. The element leaching rates in filtrate 1 obtained in step (4) are shown in Table 1-1:

[0195] Table 1-1 Element Leaching Rate

[0196] A comparison of Table 1-1 and Table 1.2 shows that the leaching rate of nickel-cobalt-manganese-iron is relatively high, indicating that less of it enters filter residue 1 for subsequent recovery, which results in the loss of nickel-cobalt-manganese-iron.

[0197] Comparative Example 2

[0198] Valuable metals were recovered using the method described in Example 2, except that magnesium oxide was replaced with an equimolar amount (based on metal element content) of Ga2O3. The element leaching rates in filtrate 1 are shown in Table 2-1.

[0199] Table 2-1 Element Leaching Rate

[0200] Ga2O3 has a poor inhibitory effect on nickel, cobalt, manganese, and iron, resulting in significant losses of these metals.

[0201] Comparative Example 3

[0202] Valuable metals were recovered using the method described in Example 2, except that magnesium oxide was replaced with an equimolar amount (based on metal element content) of CaCO3. The element leaching rates in filtrate 1 are shown in Table 3-1.

[0203] Table 3-1, Element Leaching Rate

[0204] CaCO3 has a poor inhibitory effect on nickel, cobalt, manganese, and iron, resulting in significant losses of these metals.

[0205] The preferred embodiments of this application have been described in detail above; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application. Industrial applicability

[0206] This application relates to the field of lithium battery technology and discloses a method for recovering valuable metals from lithium battery black powder. The method involves adding sulfur-containing substances and inhibitors to the lithium battery black powder, followed by calcination, water leaching, and filtration to obtain a first filtrate and a first filter residue. Lithium salts are prepared from the first filtrate, and other valuable metals are recovered from the first filter residue. The inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide. The method provided in this application recovers valuable metals from various lithium battery black powders, ensuring a high lithium recovery rate (≥98%) while allowing more of the other valuable metals to enter the residue phase (loss rate <2%) for subsequent recovery, thus improving the recovery rate of other valuable metals.

Claims

1. A method for recovering valuable metals from lithium battery black powder, characterized in that, The method includes the following steps: (1) After adding sulfur-containing substances and inhibitors to lithium battery black powder, the mixture is roasted, soaked in water, and filtered to obtain the first filtrate and the first filter residue. (2) Prepare lithium salt from the first filtrate obtained in step (1) and recover other valuable metals from the first filter residue; The inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide. The molar ratio of other valuable metals in the lithium battery black powder to the metal elements contained in the inhibitor is 1:0.05-0.

5.

2. The method according to claim 1, wherein, The lithium battery black powder is selected from at least one of ternary lithium battery black powder, lithium cobalt oxide battery black powder, lithium nickel oxide battery black powder, lithium manganese oxide battery black powder, lithium iron phosphate battery black powder, and lithium manganese iron phosphate battery black powder. And / or, the sulfur-containing substance is selected from at least one of sulfuric acid, ammonium sulfate, nickel sulfate, nickel sulfite, cobalt sulfate, cobalt sulfite, manganese sulfate, manganese sulfite, sodium sulfate, sodium sulfite, potassium sulfate, potassium sulfite, copper sulfate, copper sulfite, and ferrous sulfate; And / or, the inhibitor is selected from at least one of magnesium oxide, aluminum oxide, and calcium hydroxide; And / or, the other valuable metal is selected from at least one of nickel, cobalt, manganese and iron.

3. The method according to claim 1, wherein, The molar ratio of other valuable metals in the lithium battery black powder to the metal elements contained in the inhibitor is 1:0.05-0.2, or 1:0.05-0.

1.

4. The method according to claim 1, wherein, When the lithium battery black powder includes a first black powder and a second black powder, the sulfur-containing substance includes at least one of sulfuric acid, copper sulfate and ferrous sulfate and ammonium sulfate; wherein, the first black powder is at least one of ternary lithium battery black powder, lithium cobalt oxide battery black powder, lithium nickel oxide battery black powder and lithium manganese oxide battery black powder, and the second black powder is at least one of lithium iron phosphate battery black powder and lithium manganese iron phosphate battery black powder.

5. The method according to claim 4, wherein, The sulfuric acid has a mass concentration of 70-100%, or 80-98%. And / or, the average particle size of the ammonium sulfate is 74-245 μm, or 83-165 μm; And / or, the molar ratio of lithium in the first black powder to the total sulfur content of at least one of sulfuric acid, copper sulfate and ferrous sulfate is 1:0.5-1, or 1:0.52-0.6, or 1:0.55-0.6; And / or, the molar ratio of lithium to ammonium sulfate in the second black powder is 1:0.55-1, or 1:0.55-0.65, or 1:0.55-0.

6.

6. The method according to claim 1, wherein, The roasting includes primary roasting and / or secondary roasting; And / or, the temperature of the first calcination is 280-350℃, or 280-300℃; And / or, the roasting time for one roasting is 0.5-4 hours, or 1-2 hours.

7. The method according to claim 6, wherein, The temperature of the secondary roasting is 500-800℃ or 550-700℃; And / or, the secondary calcination time is 1-12 hours, or 3-4 hours.

8. The method according to claim 1, wherein, The liquid-to-solid ratio of the water immersion is 1.5-10:1, or 2-4:1; And / or, the immersion time is 0.5-12 hours, or 1-4 hours.

9. The method according to claim 1, wherein, Ammonia water is added to the first filtrate to obtain the second filtrate and the second filter residue; And / or, the concentration of the ammonia solution is 5-30%, or 15-25%; And / or, add ammonia to the first filtrate until the pH is greater than 11.

10. The method according to claim 1, wherein, The second filtrate was evaporated and calcined to obtain refined lithium sulfate. And / or, the calcination temperature is 500-600°C, or 550°C.

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