Method for recovering valuable metal from lithium battery black powder

Abstract

The invention relates to the technical field of lithium batteries, and discloses a method for recovering valuable metals from lithium battery black powder. Adding a sulfur-containing substance and an inhibitor into the lithium battery black powder, roasting, leaching in water, and filtering to obtain a first filtrate and a first filter residue; 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. According to the method provided by the invention, the valuable metals in various lithium battery black powder are recovered, so that other valuable metals can enter a slag phase (the loss rate is less than 2%) for subsequent recovery while a relatively high lithium recovery rate (greater than or equal to 98%) is ensured, and the recovery rates of other valuable metals are improved.

Description

Technical Field

[0001] The invention relates to the technical field of lithium batteries, and in particular to a method for recovering valuable metals from black powder of lithium batteries. Background Art

[0002] With the rapid development of electric vehicles, energy storage systems and other fields, higher requirements have been put forward for the energy density, cycle life, safety performance, etc. of lithium batteries. As a key component of the battery, the positive electrode material of lithium batteries has an important impact on the performance of lithium batteries.

[0003] Recycling lithium batteries has the dual attributes of saving metal resources and protecting the environment. The traditional wet method is to leach out all valuable metals, then remove impurities, precipitate nickel, cobalt and manganese, and finally recover lithium. When precipitating nickel, cobalt and manganese, lithium will inevitably be lost, which leads to a low lithium yield. When recycling through traditional pyrolysis, lithium remains in the flue ash and needs to be collected for secondary treatment. The recovery efficiency of other valuable metals by traditional wet and pyrolysis is also very low.

[0004] CN108832215A discloses a method for selectively recovering positive electrode materials of lithium-ion batteries, which is a typical wet-fire combined recovery method. The patent uses sulfuric acid or sulfate to evenly mix with positive electrode materials of lithium batteries, and then roasts and leaches with water. The lithium element is transferred to the aqueous solution in the form of water-soluble lithium sulfate, and most of the metal elements such as nickel and cobalt exist in the slag phase as water-insoluble oxides, and the lithium element is selectively extracted.

[0005] CN117416973A discloses a selective lithium extraction process for lithium iron manganese phosphate batteries. 1-x Fe x The PO4 battery positive electrode powder is acidified with sulfuric acid and H2SO4, then crushed, roasted, and washed with water to obtain a Li-rich solution. The Li-rich solution is pH-adjusted with a LiOH solution to remove impurities, and then the purified solution after impurities is supplemented with S. Finally, the S-supplemented solution is evaporated and crystallized to obtain Li2SO4. The advantage of this patent is that the lithium element yield is high, but the process is lengthy, the pH value is repeatedly adjusted, and the acid is supplemented twice, which consumes a large amount of acid and alkali reagents.

[0006] In the prior art methods for recovering black powder from lithium batteries, a portion of nickel, cobalt, manganese, and iron elements will form water-soluble nickel sulfate, cobalt sulfate, or ferrous sulfate and enter the water leaching solution together with lithium elements, and further impurity removal is required to remove them. This portion of valuable metals exists in the form of solid waste, causing losses.

[0007] Therefore, there is an urgent need to develop a method that is applicable to a variety of lithium battery black powders and can efficiently recover valuable metals. Summary of the invention

[0008] The purpose of the present invention is to overcome the problems existing in the prior art and provide a method for recovering valuable metals from lithium battery black powder.

[0009] In order to achieve the above object, the present invention provides a method for recovering valuable metals from lithium battery black powder, wherein the method comprises the following steps: (1) adding sulfur-containing substances and inhibitors to lithium battery black powder, and then roasting, soaking in water, and filtering to obtain a first filtrate and a first filter residue; (2) preparing lithium salt from the first filtrate obtained in step (1), 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; 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.

[0010] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows: (1) The method provided by the present invention can be used to recover valuable metals in various lithium battery black powders. While ensuring a high lithium recovery rate (≥98%), other valuable metals can be more likely to enter the slag phase (loss rate <2%) for subsequent recovery, thereby improving the recovery rate of other valuable metals.

[0011] (2) The present invention can reduce the amount of sulfur-containing substances added during roasting, thereby efficiently recovering lithium. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0013] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0014] A first aspect of the present invention provides a method for recovering valuable metals from lithium battery black powder, wherein the method comprises the following steps: (1) adding sulfur-containing substances and inhibitors to lithium battery black powder, and then roasting, soaking in water, and filtering to obtain a first filtrate and a first filter residue; (2) preparing lithium salt from the first filtrate obtained in step (1), 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; 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.

[0015] The prior art usually adds alkaline substances to the leachate after roasting and leaching to precipitate the valuable metal elements other than lithium as impurities, thereby improving the purity of the recovered lithium. In the impurity removal process, a portion of lithium is inevitably entrained into the precipitate, resulting in lithium loss, and this portion of the precipitate is usually treated as solid waste as impurity removal slag, resulting in the loss of other valuable metals.

[0016] Although CN108832215A controls the reaction conditions to decompose most of the transition metal sulfates (such as cobalt sulfate) into metal oxides and enter the solid slag for subsequent recovery, there is still a part (about 5-8%) of the transition metal sulfates that are not completely converted. This part of the transition metal sulfates will still enter the aqueous solution together with lithium during leaching (after impurity removal, generally not recovered), resulting in the loss of valuable metals (such as nickel, cobalt, manganese and iron) when the solid slag is recovered.

[0017] The invention adds a specific inhibitor before roasting, so that the valuable metals that originally cannot enter the solid slag and are leached into the leaching solution remain in the form of oxides and do not participate in leaching, so that they enter the solid slag to improve the efficiency of the subsequent valuable metal recovery process.

[0018] In the present invention, the amount of inhibitor added is calculated based on the metal elements contained therein. If the amount of inhibitor added is too little, other valuable metals will be lost greatly; if the amount of inhibitor added is too much, it is not conducive to the subsequent recovery of other valuable metals in the first filter residue.

[0019] In some embodiments of the present invention, 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 black powder (LNO), lithium manganese oxide battery (LMO) black powder, lithium iron phosphate battery (LFP) black powder and lithium manganese iron phosphate battery (LMFP) black powder. The present invention is effective not only for a single type of lithium battery black powder, but also for a mixture of multiple lithium battery black powders.

[0020] The "black powder" described in the present invention can be positive electrode black powder or mixed positive and negative electrode black powder.

[0021] In some embodiments of the present invention, 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.

[0022] In some embodiments of the present invention, the inhibitor is selected from at least one of magnesium oxide, aluminum oxide and calcium hydroxide.

[0023] In some embodiments of the present invention, the other valuable metal is selected from at least one of nickel, cobalt, manganese and iron.

[0024] In some embodiments of the present invention, 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 the present invention, when the lithium battery black powder includes the first black powder and the 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, cobalt oxide lithium battery black powder, nickel oxide lithium battery black powder and manganese oxide lithium battery black powder, and the second black powder is at least one of lithium iron phosphate battery black powder and lithium iron manganese phosphate battery black powder.

[0025] In the present invention, 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, which can reduce the usage of sulfur-containing substances and achieve the effect of efficient lithium extraction.

[0026] In actual operation, if the content of the molecules in the first black powder (lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide) and the molecules in the second black powder (lithium iron phosphate, lithium manganese iron phosphate) in the mixed black powder is unknown, it can be calculated by detecting the content of each valuable metal element.

[0027] In some embodiments of the present invention, the mass concentration of the sulfuric acid is 70-100%, preferably 80-98%.

[0028] In some embodiments of the present invention, the average particle size of the ammonium sulfate is 74-245 μm, preferably 83-165 μm.

[0029] In some embodiments of the present invention, the molar ratio of lithium in the first black powder to the total amount of sulfur contained in 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 the present invention, if the total amount of sulfur contained in at least one of sulfuric acid, copper sulfate and ferrous sulfate is too much, more nickel, cobalt, manganese and iron will be leached during water leaching, and the loss of other valuable metals will increase; if the total amount is too little, the reaction is insufficient and the lithium leaching rate will be low.

[0030] In some embodiments of the present invention, 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 the present invention, if the amount of ammonium sulfate is too much, a small part of the excess ammonium sulfate will react with the first black powder, resulting in the formation of sulfates of nickel, cobalt, manganese and iron, resulting in large leaching losses; if the amount of ammonium sulfate is too little, the reaction is insufficient, and the lithium leaching rate will be low.

[0031] In some embodiments of the present invention, the calcination includes primary calcination and / or secondary calcination.

[0032] In some embodiments of the present invention, the primary calcination temperature is 280-350°C, preferably 280-300°C.

[0033] In some embodiments of the present invention, the time of the primary calcination is 0.5-4 h, preferably 1-2 h.

[0034] In some embodiments of the present invention, the secondary calcination temperature is 500-800°C, preferably 550-700°C.

[0035] In some embodiments of the present invention, the secondary calcination time is 1-12 hours, preferably 3-4 hours.

[0036] When the lithium battery black powder is only the first black powder, sulfuric acid is used as the sulfur-containing substance, and only the above-mentioned secondary roasting conditions are used for roasting; when the lithium battery is only the second black powder, ammonium sulfate is used as the sulfur-containing substance, and only the above-mentioned primary roasting conditions are used for roasting.

[0037] 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 a ternary lithium battery black powder, a lithium cobalt oxide battery black powder, a lithium nickel oxide battery black powder and a lithium manganese oxide battery black powder, and the second black powder is at least one of a lithium iron phosphate battery black powder and a lithium iron manganese phosphate battery black powder, the roasting is performed sequentially using the conditions of a primary roasting and a secondary roasting.

[0038] In the present invention, by further limiting the conditions of the primary calcination and the secondary calcination, a higher lithium yield can be obtained with a smaller amount of sulfur-containing substances, which will also affect the amount of other valuable metals enriched in the first filter residue.

[0039] When the lithium battery black powder is only the first black powder, sulfuric acid is used as the sulfur-containing substance, and only the above-mentioned secondary roasting conditions are used for roasting; when the lithium battery is only the second black powder, ammonium sulfate is used as the sulfur-containing substance, and only the above-mentioned primary roasting conditions are used for roasting.

[0040] In some embodiments of the present invention, the liquid-to-solid ratio of the water immersion is 1.5-10:1, preferably 2-4:1.

[0041] In some embodiments of the present invention, the immersion time is 0.5-12 h, preferably 1-4 h.

[0042] In some embodiments of the present invention, ammonia water is added to the first filtrate to obtain a second filtrate and a second filter residue. The purpose of adding ammonia water is to remove metal elements in the added inhibitor.

[0043] In some embodiments of the present invention, the concentration of the aqueous ammonia is 5-30%, preferably 15-25%.

[0044] In some embodiments of the present invention, aqueous ammonia is added to the first filtrate until the pH is greater than 11.

[0045] In some embodiments of the present invention, the second filtrate is evaporated and roasted to obtain refined lithium sulfate. Crude lithium sulfate is obtained after evaporation and then roasted to purify it into refined lithium sulfate.

[0046] In some embodiments of the present invention, the calcination temperature is 500-600°C, preferably 550°C.

[0047] The present invention will be described in detail below through examples.

[0048] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be obtained through commercial channels.

[0049] 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 molecule in the second black powder is LiFePO4 or LiMn a Fe b PO4 (a+b=1, hereinafter referred to as the second molecule).

[0050] Example 1 This embodiment is used to illustrate the method of recovering valuable metals when the lithium battery black powder is a mixture of the first black powder and the second black powder. Figure 1 shown.

[0051] After testing, the content of valuable metal elements in the black powder used in this embodiment is as follows: Table 1.1, Content of valuable metal elements in black powder .

[0052] According to calculation, the content of the first molecule in the black powder is 77% (relative to the positive electrode material), and the content of the second molecule is 23% (relative to the positive electrode material).

[0053] (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 1:0.55, and the concentration of sulfuric acid 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 165 μm; the molar ratio of the total amount of nickel, cobalt, manganese and iron in the black powder to the magnesium element in magnesium oxide is 1:0.05; (2) calcining the black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide at 280° C. for 1 hour to obtain a single-calcined black powder; (3) The primary calcined black powder is secondary calcined at 600° C. for 3 hours to obtain secondary calcined black powder; (4) Add water to the secondary roasted black powder at room temperature, stir and leach, and filter 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-solid ratio is 4:1, and the leaching time is 1 hour; the element leaching rate in filtrate 1 is shown in Table 1.2: Table 1.2, Element leaching rate .

[0054] (5) Add ammonia water (concentration of 20%) to the filtrate 1 and stir. When the pH value is greater than 11 and does not change any more, stop adding and filter to obtain the filtrate 2 and the filter residue 2; the filter residue 2 is the impurity-removed residue; (6) evaporating the filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate; (7) The crude ammonium sulfate crystals were calcined at 550°C to remove the ammonium sulfate and crystal water, thereby obtaining refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0055] Example 2

[0056] This embodiment is used to illustrate 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.

[0057] After testing, the content of valuable metal elements in the black powder used in this embodiment is as follows: Table 2.1, Content of valuable metal elements in black powder .

[0058] According to calculation, the content of the first molecule in the black powder is 47% (relative to the positive electrode material), and the content of the second molecule is 53% (relative to the positive electrode material).

[0059] (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 concentration of sulfuric acid 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 198 μm; the molar ratio of the total amount of nickel, cobalt, manganese and iron in the black powder to the magnesium element in magnesium oxide is 1:0.1; (2) calcining the black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide at 300° C. for 2 hours to obtain a single-calcined black powder; (3) The primary calcined black powder is secondary calcined at 570° C. for 3 hours to obtain secondary calcined black powder; (4) Add water to the secondary roasted black powder at room temperature, stir and leach, and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel-cobalt-manganese-iron enriched product, which can be used for subsequent recovery of nickel-cobalt-manganese-iron; the leaching liquid-solid ratio is 2:1, and the leaching time is 2 hours; the element leaching rate in filtrate 1 is shown in Table 2.2: Table 2.2, Element leaching rate .

[0060] (5) Add ammonia water (concentration of 15%) to the filtrate 1 and stir. When the pH value is greater than 11 and does not change any more, stop adding and filter to obtain the filtrate 2 and the filter residue 2; the filter residue 2 is the impurity-removing residue; (6) evaporating the filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate; (7) The crude ammonium sulfate crystals were calcined at 550°C to remove the ammonium sulfate and crystal water, thereby obtaining refined lithium sulfate with a purity of 99.6% and a lithium yield of 98.5%.

[0061] Example 3 This embodiment is used to illustrate 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.

[0062] After testing, the content of valuable metal elements in the black powder used in this embodiment is as follows: Table 3.1, Content of valuable metal elements in black powder .

[0063] According to calculation, the content of the first molecule in the black powder is 14% (relative to the positive electrode material), and the content of the second molecule is 86% (relative to the positive electrode material).

[0064] (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 concentration of sulfuric acid 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 150 μm; the molar ratio of the total amount of nickel, cobalt, manganese and iron in the black powder to the magnesium element in magnesium oxide is 1:0.5; (2) calcining the black powder mixed with sulfuric acid, ammonium sulfate and magnesium oxide at 290° C. for 2 hours to obtain a single-calcined black powder; (3) the primary calcined black powder is secondary calcined at 550°C for 3 hours to obtain secondary calcined black powder; (4) Add water to the secondary roasted black powder at room temperature, stir and leach, and filter 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-solid ratio is 3:1, and the leaching time is 1 hour; the element leaching rate in filtrate 1 is shown in Table 3.2: Table 3.2, Element leaching rate .

[0065] (5) Add ammonia water (concentration of 20%) to the filtrate 1 and stir. When the pH value is greater than 11 and does not change any more, stop adding and filter to obtain the filtrate 2 and the filter residue 2; the filter residue 2 is the impurity-removed residue; (6) evaporating the filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate; (7) The crude ammonium sulfate crystals were calcined at 550°C to remove the ammonium sulfate and water of crystallization to obtain refined lithium sulfate with a purity of 99.6% and a lithium yield of 98.3%.

[0066] Example 4 This embodiment is used to illustrate a method for recovering valuable metals when the lithium battery black powder is the first black powder.

[0067] After testing, the content of valuable metal elements in the black powder used in this embodiment is as follows: Table 4.1, Content of valuable metal elements in black powder .

[0068] (1) Add sulfuric acid 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 1:0.52, and the concentration of sulfuric acid is 98%; the molar ratio of the total amount of nickel, cobalt and manganese in the black powder to the magnesium element in magnesium oxide is 1:0.05; (2) calcining the black powder mixed with sulfuric acid and magnesium oxide at 600° C. for 3 hours to obtain calcined black powder; (3) Add water to the roasted black powder at room temperature, stir and leach, and filter 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-solid ratio is 4:1, and the leaching time is 1 hour; the element leaching rate in filtrate 1 is shown in Table 4.2: Table 4.2, Element leaching rate .

[0069] (4) Add ammonia water (concentration of 20%) to the filtrate 1 and stir. When the pH value is greater than 11 and does not change any more, stop adding and filter to obtain the filtrate 2 and the filter residue 2; the filter residue 2 is the impurity-removed residue; (5) evaporating the filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate; (6) The crude ammonium sulfate crystals were calcined at 550°C to remove the ammonium sulfate and crystal water, thereby obtaining refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0070] Example 5 This embodiment is used to illustrate a method for recovering valuable metals when the lithium battery black powder is the second black powder.

[0071] After testing, the content of valuable metal elements in the black powder used in this embodiment is as follows: Table 5.1, Content of valuable metal elements in black powder .

[0072] (1) Add ammonium sulfate and magnesium oxide to the lithium battery black powder and mix them 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 165 μm; the molar ratio of the total amount of manganese iron in the black powder to the magnesium element in magnesium oxide is 1:0.05; (2) roasting the black powder mixed with ammonium sulfate and magnesium oxide at 280° C. for 1 hour to obtain roasted black powder; (3) Add water to the roasted black powder at room temperature, stir and leach, and filter 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-solid ratio is 4:1, and the leaching time is 1 hour; the element leaching rate in filtrate 1 is shown in Table 5.2: Table 5.2, Element leaching rate .

[0073] (4) Add ammonia water (concentration of 20%) to the filtrate 1 and stir. When the pH value is greater than 11 and does not change any more, stop adding and filter to obtain the filtrate 2 and the filter residue 2; the filter residue 2 is the impurity-removed residue; (5) evaporating the filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate; (6) The crude ammonium sulfate crystals were calcined at 550°C to remove the ammonium sulfate and crystal water, thereby obtaining refined lithium sulfate with a purity of 99.7% and a lithium yield of 99.1%.

[0074] Example 6 Valuable metals were recovered according to the method of Example 1, except that the molar ratio of the total amount of nickel, cobalt, manganese and iron in the black powder to the magnesium element in magnesium oxide was 1:0.04. The element leaching rate in the filtrate 1 was shown in Table 6.1: Table 6.1, Element leaching rate .

[0075] The purity of the refined lithium sulfate obtained was 99.6%, and the lithium yield was 96.3%.

[0076] Example 7 Valuable metals were recovered according to the method of Example 1, except that the molar ratio of the total amount of nickel, cobalt, manganese and iron in the black powder to the magnesium element in magnesium oxide was 1:0.6. The element leaching rate in the filtrate 1 was shown in Table 7.1: Table 7.1, Element leaching rate .

[0077] The obtained refined lithium sulfate has a purity of 99.5% and a lithium yield of 98.5%.

[0078] Example 8 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:0.5. The element leaching rate in the filtrate 1 was shown in Table 8.1: Table 8.1, Element leaching rate .

[0079] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 98.6%.

[0080] Example 9 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:1. The element leaching rate in filtrate 1 was shown in Table 9.1: Table 9.1, Element leaching rate .

[0081] The purity of the refined lithium sulfate obtained was 99.6%, and the lithium yield was 98.8%.

[0082] Example 10 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:0.4. The element leaching rate in the filtrate 1 was shown in Table 10.1: Table 10.1, Element leaching rate .

[0083] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 82.4%.

[0084] Embodiment 11 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule was 1:1.1. The element leaching rate in the filtrate 1 was shown in Table 11.1: Table 11.1. Element leaching rate .

[0085] The purity of the refined lithium sulfate obtained was 99.6%, and the lithium yield was 98.0%.

[0086] Example 12 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:1. The element leaching rate in filtrate 1 was shown in Table 12.1: Table 12.1, Element leaching rate .

[0087] Refined lithium sulfate was obtained with a purity of 99.8% and a lithium yield of 98.8%.

[0088] Embodiment 13 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:0.3. The element leaching rate in filtrate 1 was shown in Table 13.1: Table 13.1, Element leaching rate .

[0089] The purity of the refined lithium sulfate obtained was 99.6%, and the lithium yield was 86.9%.

[0090] Embodiment 14 Valuable metals were recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule was 1:1.2; the element leaching rate in filtrate 1 is shown in Table 14.1: Table 14.1, Element leaching rate .

[0091] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 96.8%.

[0092] Embodiment 15 Valuable metals were recovered according to the method of Example 3, except that the primary calcination temperature was 260°C.

[0093] The element leaching rates in filtrate 1 are shown in Table 15.1: Table 15.1, Element leaching rate .

[0094] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 82.7%.

[0095] Example 16 Valuable metals were recovered according to the method of Example 3, except that the primary calcination temperature was 360°C.

[0096] The element leaching rates in filtrate 1 are shown in Table 16.1: Table 16.1. Element leaching rate .

[0097] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 92.3%.

[0098] Embodiment 17 Valuable metals were recovered according to the method of Example 3, except that the secondary calcination temperature was 480°C.

[0099] The element leaching rates in filtrate 1 are shown in Table 17.1: Table 17.1. Element leaching rate .

[0100] The purity of the refined lithium sulfate obtained was 99.6%, and the lithium yield was 64.3%.

[0101] Embodiment 18 Valuable metals were recovered according to the method of Example 3, except that the secondary roasting temperature was 850°C. The element leaching rates in the obtained filtrate 1 are shown in Table 18.1: Table 18.1. Element leaching rates .

[0102] The purity of the refined lithium sulfate obtained was 99.7%, and the lithium yield was 78.2%.

[0103] Embodiment 19 Valuable metals were recovered according to the method of Example 1, except that sulfuric acid was replaced with an equal molar amount of ammonium sulfate. The element leaching rates in the obtained filtrate 1 are shown in Table 19.1: Table 19.1. Element leaching rate .

[0104] Refined lithium sulfate was obtained with a purity of 99.7% and a lithium yield of 82.1%.

[0105] Embodiment 20 Valuable metals were recovered according to the method of Example 1, except that ammonium sulfate was replaced with an equimolar amount of sulfuric acid. The element leaching rates in the obtained filtrate 1 are shown in Table 20.1: Table 20.1. Element leaching rate .

[0106] Refined lithium sulfate was obtained with a purity of 99.6% and a lithium yield of 82.9%.

[0107] Embodiment 21 Valuable metals were recovered according to the method of Example 1, except that magnesium oxide was replaced with an equimolar amount (in terms of metal element) of calcium hydroxide. The element leaching rates in the obtained filtrate 1 are shown in Table 21.1: Table 21.1. Element leaching rate .

[0108] Refined lithium sulfate was obtained with a purity of 99.7% and a lithium yield of 99.2%. Calcium hydroxide inhibited the leaching of nickel, cobalt, manganese and iron, causing them to be transferred to the filter residue 1.

[0109] Embodiment 22 Valuable metals were recovered according to the method of Example 1, except that magnesium oxide was replaced with an equimolar amount (in terms of metal elements) of aluminum oxide. The element leaching rates in the obtained filtrate 1 are shown in Table 22.1: Table 22.1. Element leaching rate .

[0110] Refined lithium sulfate was obtained with a purity of 99.5% and a lithium yield of 99.1%. Alumina inhibited the leaching of nickel, cobalt, manganese and iron, causing them to be transferred to the filter residue 1.

[0111] Comparative Example 1 Valuable metals were recovered according to the method of Example 1, except that magnesium oxide was not added. The element leaching rate in the filtrate 1 obtained in step (4) is shown in Table 1-1: Table 1-1, Element leaching rate .

[0112] From the comparison between Table 1-1 and Table 1.2, it can be seen that the leaching rate of nickel-cobalt-manganese-iron is relatively large, indicating that the amount entering the filter residue 1 for subsequent recovery is relatively small, which causes the loss of nickel-cobalt-manganese-iron.

[0113] Comparative Example 2 Valuable metals were recovered according to the method of Example 2, except that magnesium oxide was replaced with an equimolar amount (in terms of metal element) of Ga2O3. The element leaching rates in filtrate 1 are shown in Table 2-1: Table 2-1, Element leaching rate .

[0114] Ga2O3 has a poor inhibitory effect on nickel, cobalt, manganese and iron, resulting in a large loss of nickel, cobalt, manganese and iron.

[0115] Comparative Example 3 Valuable metals were recovered according to the method of Example 2, except that magnesium oxide was replaced with an equimolar amount (in terms of metal elements) of CaCO3. The element leaching rates in filtrate 1 are shown in Table 3-1: Table 3-1, Element leaching rate .

[0116] CaCO3 has a poor inhibitory effect on nickel, cobalt, manganese and iron, resulting in a large loss of nickel, cobalt, manganese and iron.

[0117] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for recovering valuable metals from lithium battery black powder, characterized in that: The method comprises the following steps: (1) adding sulfur-containing substances and inhibitors to lithium battery black powder, and then roasting, soaking in water, and filtering to obtain a first filtrate and a first filter residue; (2) preparing lithium salt from the first filtrate obtained in step (1), 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; 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 a ternary lithium battery black powder, a lithium cobalt oxide battery black powder, a lithium nickel oxide battery black powder and a lithium manganese oxide battery black powder, and the second black powder is at least one of a lithium iron phosphate battery black powder and a lithium iron manganese phosphate battery black powder.

5. The method according to claim 4, wherein: The mass concentration of the sulfuric acid is 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 amount of sulfur contained in 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 primary calcination temperature is 280-350°C, or 280-300°C; And / or, the time of the first calcination is 0.5-4h, or 1-2h.

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

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 0.5-12h, or 1-4h.

9. The method according to claim 1, wherein: Adding aqueous ammonia to the first filtrate to obtain a second filtrate and a second filter residue; And / or, the concentration of the aqueous ammonia is 5-30%, or 15-25%; And / or, adding aqueous ammonia to the first filtrate until the pH value is greater than 11.

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

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