Method for Recycling Valuable Metals from Lithium Battery Black Powder

Abstract

The present invention relates to the technical field of lithium batteries, and discloses a method for recovering valuable metals from lithium battery black powder. After adding a sulfur-containing substance and an inhibitor to the lithium battery black powder, roasting, water leaching, and filtration are carried out to obtain a first filtrate and a first filter residue; a lithium salt is prepared from the obtained first filtrate, and other valuable metals are recovered 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 using the method provided by the present invention to recover valuable metals from various lithium battery black powders, while ensuring a high lithium recovery rate (≥98%), other valuable metals can enter the slag phase more (loss rate <2%) for subsequent recovery, improving the recovery rate of other valuable metals.

Description

Technical Field

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

[0002] 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.

[0003] Recycling lithium batteries has the dual attributes of saving metal resources and environmental protection. In traditional hydrometallurgy, all valuable metals are leached out, then impurities are removed, nickel, cobalt, and manganese are precipitated, and finally lithium is recovered. When precipitating nickel, cobalt, and manganese, lithium will inevitably be lost, resulting in a low recovery rate of lithium. When recovering by 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.

[0004] CN108832215A discloses a method for selectively recovering 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 be uniformly mixed with the cathode material of lithium batteries, then roasted and leached with water. Lithium elements are transferred into 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 lithium elements are selectively extracted.

[0005] CN117416973A discloses a selective lithium extraction process for lithium iron phosphate batteries. The waste cathode powder of LiMn 1-x Fe x PO 4 batteries is acidified with H 2 SO 4 , then crushed, roasted, and washed with water to obtain a Li-rich solution. The Li-rich solution is adjusted with LiOH solution to remove impurities, then S is added to the purified solution after impurity removal, and finally the S-added solution is evaporated and crystallized to obtain Li 2 SO 4 . The advantage of this patent is the high recovery rate of lithium elements, but the process is lengthy, the pH value is repeatedly adjusted and acid is added secondly, consuming a large amount of acid and alkali reagents.

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

[0007] Therefore, there is an urgent need to develop a method applicable to various lithium battery black powders and capable of efficiently recovering 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] To achieve the above purpose, the present invention provides a method for recovering valuable metals from lithium battery black powder, wherein the method comprises the following steps:

[0010] (1) Add a sulfur-containing substance and an inhibitor to the lithium battery black powder, then carry out roasting, water leaching, and filtration to obtain a first filtrate and a first filter residue;

[0011] (2) Prepare a lithium salt from the first filtrate obtained in step (1) and recover other valuable metals from the first filter residue;

[0012] Wherein, the inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide;

[0013] 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.

[0014] Through the above technical solution, the beneficial technical effects obtained by the present invention are as follows:

[0015] (1) By using the method provided by the present invention to recover valuable metals in various lithium battery black powders, while ensuring a high lithium recovery rate (≥98%), other valuable metals can enter the slag phase more (loss rate < 2%) for subsequent recovery, improving the recovery rate of other valuable metals.

[0016] (2) The present invention can reduce the dosage of the sulfur-containing substance added during roasting, thereby efficiently recovering lithium. Brief Description of the Drawings

[0017] Figure 1 is the process flow chart of the present invention. Detailed Embodiments

[0018] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0019] The first aspect of the present invention provides a method for recovering valuable metals from black powder of lithium batteries. Wherein, the method comprises the following steps:

[0020] (1) Add a sulfur-containing substance and an inhibitor to the black powder of lithium batteries, then carry out roasting, water leaching, and filtration to obtain a first filtrate and a first filter residue;

[0021] (2) Prepare lithium salts from the first filtrate obtained in step (1), and recover other valuable metals from the first filter residue;

[0022] Wherein, the inhibitor is selected from at least one of magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, and aluminum hydroxide;

[0023] The molar ratio of other valuable metals in the black powder of lithium batteries to the metal elements contained in the inhibitor is 1:0.05 - 0.5.

[0024] The prior art usually adds alkaline substances to the leaching solution after roasting and leaching, so that valuable metal elements other than lithium precipitate as impurities, thereby improving the purity of the recovered lithium. However, during the impurity removal process, a part of lithium is inevitably carried into the precipitate at the same time, resulting in the loss of lithium, and this part of the precipitate is usually treated as solid waste as impurity removal slag, resulting in the loss of other valuable metals.

[0025] Although CN108832215A decomposes most of the transition metal sulfates (such as cobalt sulfate) into metal oxides to enter the solid slag for subsequent recovery by controlling the reaction conditions, there is still a part (about 5 - 8%) of the transition metal sulfates that are not completely converted, and this part of the transition metal sulfates will still enter the aqueous solution together with lithium during leaching (removed by impurity removal and generally not recovered), resulting in the loss of valuable metals (such as nickel, cobalt, manganese, and iron) during the recovery of the solid slag.

[0026] The present invention adds a specific inhibitor before roasting, so that valuable metals that originally could not enter the solid slag and were leached into the leaching solution remain in the form of oxides and do not participate in leaching, thereby entering the solid slag to improve the efficiency of the subsequent valuable metal recovery process.

[0027] In the present invention, the addition amount of the inhibitor is calculated based on the metal elements contained therein. If the addition amount of the inhibitor is too small, the loss of other valuable metals will be large; if the addition amount of the inhibitor is too large, it is not conducive to the subsequent recovery of other valuable metals in the first filter residue.

[0028] In some embodiments of the present invention, the black powder of lithium battery is selected from at least one of the black powder of ternary lithium battery (NCM), the black powder of lithium cobalt oxide battery (LCO), the black powder of lithium nickel oxide battery (LNO), the black powder of lithium manganese oxide battery (LMO), the black powder of lithium iron phosphate battery (LFP), and the black powder of lithium manganese iron phosphate battery (LMFP). The present invention is not only effective for a single type of black powder of lithium battery, but also has the same effect on the mixture of various black powders of lithium battery.

[0029] The "black powder" described in the present invention can be the black powder of the positive electrode or the mixed black powder of the positive and negative electrodes.

[0030] 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.

[0031] In some embodiments of the present invention, the inhibitor is selected from at least one of magnesium oxide, aluminum oxide, and calcium hydroxide.

[0032] In some embodiments of the present invention, the other valuable metals are selected from at least one of nickel, cobalt, manganese, and iron.

[0033] In some embodiments of the present invention, the molar ratio of the other valuable metals in the black powder of lithium battery 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 black powder of lithium battery 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 the black powder of ternary lithium battery, the black powder of lithium cobalt oxide battery, the black powder of lithium nickel oxide battery, and the black powder of lithium manganese oxide battery, and the second black powder is at least one of the black powder of lithium iron phosphate battery and the black powder of lithium manganese iron phosphate battery.

[0034] 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 amount of the sulfur-containing substance and achieve the effect of efficient lithium extraction.

[0035] In actual operation, if the contents of the molecules (lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide) in the first black powder and the molecules (lithium iron phosphate, lithium manganese iron phosphate) in the second black powder in the mixed black powder cannot be known, it can be calculated by detecting the contents of various valuable metal elements.

[0036] In some embodiments of the present invention, the mass concentration of the sulfuric acid is 70 - 100%, preferably 80 - 98%.

[0037] In some embodiments of the present invention, the average particle size of the ammonium sulfate is 74 - 245 μm, preferably 83 - 165 μm.

[0038] In some embodiments of the present invention, the molar ratio of lithium in the first black powder to the total sulfur content 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 sulfur content in at least one of sulfuric acid, copper sulfate, and ferrous sulfate is too high, more nickel, cobalt, manganese, and iron will be leached during water leaching, and at this time, the loss of other valuable metals will increase; if the total amount is too small, the reaction will be insufficient and the lithium leaching rate will be low.

[0039] In some embodiments of the present invention, the molar ratio of lithium in the second black powder to ammonium sulfate 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 large, 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, and a large loss in leaching; if the amount of ammonium sulfate is too small, the reaction will be insufficient and the lithium leaching rate will be low.

[0040] In some embodiments of the present invention, the roasting includes primary roasting and / or secondary roasting.

[0041] In some embodiments of the present invention, the temperature of the primary roasting is 280 - 350 °C, preferably 280 - 300 °C.

[0042] In some embodiments of the present invention, the time of the primary roasting is 0.5 - 4 h, preferably 1 - 2 h.

[0043] In some embodiments of the present invention, the temperature of the secondary roasting is 500 - 800 °C, preferably 550 - 700 °C.

[0044] In some embodiments of the present invention, the time of the secondary roasting is 1 - 12 h, preferably 3 - 4 h.

[0045] 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 conditions for secondary roasting 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 conditions for primary roasting are used for roasting.

[0046] When the lithium battery black powder includes the first black powder and the 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 conditions of primary roasting and secondary roasting are used for roasting in sequence.

[0047] In the present invention, by further defining the conditions of the first roasting and the second roasting, a higher lithium recovery rate can be obtained with a smaller amount of sulfur-containing substances, and it will also affect the amount of other valuable metals enriched in the first filter residue.

[0048] 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 conditions of the second roasting 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 conditions of the first roasting are used for roasting.

[0049] In some embodiments of the present invention, the liquid-solid ratio of the water leaching is 1.5 - 10:1, preferably 2 - 4:1.

[0050] In some embodiments of the present invention, the water leaching time is 0.5 - 12 h, preferably 1 - 4 h.

[0051] 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 the metal elements in the added inhibitor.

[0052] In some embodiments of the present invention, the concentration of the ammonia water is 5 - 30%, preferably 15 - 25%.

[0053] In some embodiments of the present invention, ammonia water is added to the first filtrate until the pH is greater than 11.

[0054] In some embodiments of the present invention, the second filtrate is evaporated and roasted to obtain refined lithium sulfate. After evaporation, crude lithium sulfate is obtained, and then it is purified into refined lithium sulfate by roasting.

[0055] In some embodiments of the present invention, the temperature of the roasting is 500 - 600 °C, preferably 550 °C.

[0056] The present invention will be described in detail below through examples.

[0057] In the following examples and comparative examples, those not specifying specific conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial channels.

[0058] In the following examples and comparative examples, the molecule in the first black powder is LiNi x Co y Mn z O 2 (x + y + z = 1, hereinafter referred to as the first molecule), and the molecule in the second black powder is LiFePO 4 or LiMn a Feb PO 4 (a + b = 1, hereinafter referred to as the second molecule).

[0059] Example 1

[0060] This example is used to illustrate the method for recovering valuable metals when the black powder of lithium battery is a mixture of the first black powder and the second black powder. As Figure 1 shown.

[0061] After detection, the contents of valuable metal elements in the black powder used in this example are as follows:

[0062] Table 1.1, Contents of Valuable Metal Elements in Black Powder

[0063] .

[0064] After calculation, 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).

[0065] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to the black powder of lithium battery and mix 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 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;

[0066] (2) Roast the black powder mixed with sulfuric acid, ammonium sulfate, and magnesium oxide at 280 °C for 1 hour to obtain the first-roasted black powder;

[0067] (3) Roast the first-roasted black powder at 600 °C for 3 hours to obtain the second-roasted black powder;

[0068] (4) Stir and leach the second-roasted black powder with water at room temperature and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel, cobalt, manganese, and iron concentrate, which can be used for subsequent recovery of nickel, cobalt, manganese, and iron; the liquid-solid ratio of leaching is 4:1, and the leaching time is 1 hour; the leaching rate of elements in filtrate 1 is shown in Table 1.2:

[0069] Table 1.2, Element Leaching Rate

[0070] .

[0071] (5) Add ammonia water (concentration 20%) to filtrate 1, stir, and stop adding when the pH value > 11 and no longer changes, then 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) Roast the crude ammonium sulfate crystals at 550 °C to remove ammonium sulfate and crystal water, obtaining refined lithium sulfate with a purity of 99.7% and a lithium recovery rate of 99.1%.

[0074] Example 2

[0075] This example is used to illustrate the method for recovering valuable metals when the lithium battery black powder is a mixture of the first black powder and the second black powder.

[0076] After testing, the contents of valuable metal elements in the black powder used in this example are as follows:

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

[0078] 。

[0079] After calculation, 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).

[0080] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to the lithium battery black powder and mix 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 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;

[0081] (2) Roast the black powder mixed with sulfuric acid, ammonium sulfate, and magnesium oxide at 300 °C for 2 hours to obtain the first-roasted black powder;

[0082] (3) Roast the first-roasted black powder at 570 °C for 3 hours to obtain the second-roasted black powder;

[0083] (4) Stir and leach the second-roasted black powder with water at room temperature and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel, cobalt, manganese, and iron concentrate, which can be used for subsequent recovery of nickel, cobalt, manganese, and iron; the liquid-solid ratio of leaching is 2:1, and the leaching time is 2 hours; the element leaching rates in filtrate 1 are shown in Table 2.2:

[0084] Table 2.2 Element Leaching Rates

[0085] 。

[0086] (5) Add ammonia water (concentration 15%) to filtrate 1, stir, and stop adding when the pH value > 11 and no longer changes, then filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue;

[0087] (6) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0088] (7) Roast the crude ammonium sulfate crystals at 550 °C to remove ammonium sulfate and crystal water, obtaining refined lithium sulfate with a purity of 99.6% and a lithium yield of 98.5%.

[0089] Example 3

[0090] This example is used to illustrate the method for recovering valuable metals when the lithium battery black powder is a mixture of the first black powder and the second black powder.

[0091] After testing, the contents of valuable metal elements in the black powder used in this example are as follows:

[0092] Table 3.1, Contents of Valuable Metal Elements in Black Powder

[0093] 。

[0094] After calculation, 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).

[0095] (1) Add sulfuric acid, ammonium sulfate, and magnesium oxide to the 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 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;

[0096] (2) Roast the black powder mixed with sulfuric acid, ammonium sulfate, and magnesium oxide at 290 °C for 2 hours to obtain the first-roasted black powder;

[0097] (3) Roast the first-roasted black powder at 550 °C for 3 hours to obtain the second-roasted black powder;

[0098] (4) Stir and leach the second-roasted black powder with water at room temperature and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel, cobalt, manganese, and iron concentrate, which can be used for subsequent recovery of nickel, cobalt, manganese, and iron; the liquid-solid ratio of leaching is 3:1, and the leaching time is 1 hour; the element leaching rates in filtrate 1 are shown in Table 3.2:

[0099] Table 3.2, Element Leaching Rates

[0100] 。

[0101] (5) Add ammonia water (concentration 20%) to filtrate 1, stir, and stop adding when the pH value > 11 and no longer changes, then filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue;

[0102] (6) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0103] (7) Roast the crude ammonium sulfate crystals at 550 °C to remove ammonium sulfate and crystal water, obtaining refined lithium sulfate with a purity of 99.6% and a lithium recovery rate of 98.3%.

[0104] Example 4

[0105] This example is used to illustrate the method for recovering valuable metals when the lithium battery black powder is the first black powder.

[0106] After detection, the contents of valuable metal elements in the black powder used in this example are as follows:

[0107] Table 4.1 Contents of Valuable Metal Elements in Black Powder

[0108] 。

[0109] (1) Add sulfuric acid and magnesium oxide to the 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 magnesium element in magnesium oxide is 1:0.05;

[0110] (2) Roast the black powder mixed with sulfuric acid and magnesium oxide at 600 °C for 3 hours to obtain roasted black powder;

[0111] (3) Stir and leach the roasted black powder with water at room temperature and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel, cobalt, and manganese concentrate, which can be used for subsequent recovery of nickel, cobalt, and manganese; the liquid-solid ratio of leaching is 4:1, and the leaching time is 1 hour; the element leaching rates in filtrate 1 are shown in Table 4.2:

[0112] Table 4.2 Element Leaching Rates

[0113] 。

[0114] (4) Add ammonia water (concentration 20%) to filtrate 1, stir, and stop adding when the pH value > 11 and no longer changes, then filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue;

[0115] (5) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0116] (6) Roast the crude ammonium sulfate crystals at 550 °C to remove ammonium sulfate and crystal water, obtaining refined lithium sulfate with a purity of 99.7% and a lithium recovery rate of 99.1%.

[0117] Example 5

[0118] This example is used to illustrate the method for recovering valuable metals when the lithium battery black powder is the second black powder.

[0119] After detection, the contents of valuable metal elements in the black powder used in this embodiment are as follows:

[0120] Table 5.1, Contents of Valuable Metal Elements in Black Powder

[0121] 。

[0122] (1) Add ammonium sulfate and magnesium oxide to the black powder of lithium battery 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 165 μm; the molar ratio of the total amount of manganese and iron in the black powder to the magnesium element in magnesium oxide is 1:0.05;

[0123] (2) Roast the black powder mixed with ammonium sulfate and magnesium oxide at 280 °C for 1 hour to obtain roasted black powder;

[0124] (3) Stir and leach the roasted black powder with water at room temperature and filter to obtain filtrate 1 and filter residue 1; filter residue 1 is the nickel-cobalt-manganese-iron concentrate, which can be used for subsequent recovery of nickel, cobalt, manganese and iron; the liquid-solid ratio of leaching is 4:1, and the leaching time is 1 hour; the element leaching rates in filtrate 1 are shown in Table 5.2:

[0125] Table 5.2, Element Leaching Rates

[0126] 。

[0127] (4) Add ammonia water (concentration 20%) to filtrate 1, stir, and stop adding when the pH value > 11 and no longer changes, then filter to obtain filtrate 2 and filter residue 2; filter residue 2 is the impurity removal residue;

[0128] (5) Evaporate filtrate 2 to obtain crude lithium sulfate crystals containing ammonium sulfate;

[0129] (6) Roast the crude ammonium sulfate crystals at 550 °C to remove ammonium sulfate and crystal water, and obtain refined lithium sulfate with a purity of 99.7% and a lithium recovery rate of 99.1%.

[0130] Example 6

[0131] Recover valuable metals 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 is 1:0.04, and the element leaching rates in filtrate 1 are shown in Table 6.1:

[0132] Table 6.1, Element Leaching Rates

[0133] 。

[0134] The obtained refined lithium sulfate has a purity of 99.6% and a lithium recovery rate of 96.3%.

[0135] Example 7

[0136] The valuable metals are 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 is 1:0.6. The element leaching rates in the filtrate 1 are shown in Table 7.1:

[0137] Table 7.1, Element Leaching Rates

[0138] 。

[0139] The obtained purified lithium sulfate has a purity of 99.5% and a lithium recovery rate of 98.5%.

[0140] Example 8

[0141] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.5. The element leaching rates in the filtrate 1 are shown in Table 8.1:

[0142] Table 8.1, Element Leaching Rates

[0143] 。

[0144] The obtained purified lithium sulfate has a purity of 99.7% and a lithium recovery rate of 98.6%.

[0145] Example 9

[0146] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule is 1:1. The element leaching rates in the filtrate 1 are shown in Table 9.1:

[0147] Table 9.1, Element Leaching Rates

[0148] 。

[0149] The obtained purified lithium sulfate has a purity of 99.6% and a lithium recovery rate of 98.8%.

[0150] Example 10

[0151] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule is 1:0.4. The element leaching rates in the filtrate 1 are shown in Table 10.1:

[0152] Table 10.1, Element Leaching Rates

[0153] 。

[0154] The obtained purified lithium sulfate has a purity of 99.7% and a lithium recovery rate of 82.4%.

[0155] Example 11

[0156] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to sulfuric acid in the first molecule is 1:1.1, and the element leaching rates in filtrate 1 are shown in Table 11.1:

[0157] Table 11.1, Element Leaching Rates

[0158] 。

[0159] The obtained purified lithium sulfate has a purity of 99.6% and a lithium recovery rate of 98.0%.

[0160] Example 12

[0161] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule is 1:1, and the element leaching rates in filtrate 1 are shown in Table 12.1:

[0162] Table 12.1, Element Leaching Rates

[0163] 。

[0164] The obtained purified lithium sulfate has a purity of 99.8% and a lithium recovery rate of 98.8%.

[0165] Example 13

[0166] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule is 1:0.3, and the element leaching rates in filtrate 1 are shown in Table 13.1:

[0167] Table 13.1, Element Leaching Rates

[0168] 。

[0169] The obtained purified lithium sulfate has a purity of 99.6% and a lithium recovery rate of 86.9%.

[0170] Example 14

[0171] The valuable metals are recovered according to the method of Example 2, except that the molar ratio of lithium to ammonium sulfate in the second molecule is 1:1.2; the element leaching rates in filtrate 1 are shown in Table 14.1:

[0172] Table 14.1, Element Leaching Rates

[0173] 。

[0174] The obtained purified lithium sulfate has a purity of 99.7% and a lithium recovery rate of 96.8%.

[0175] Example 15

[0176] The valuable metals are recovered according to the method of Example 3, except that the primary roasting temperature is 260 °C.

[0177] The leaching rates of elements in filtrate 1 are shown in Table 15.1:

[0178] Table 15.1, Element leaching rates

[0179] 。

[0180] The purity of the obtained refined lithium sulfate is 99.7%, and the lithium recovery rate is 82.7%.

[0181] Example 16

[0182] The valuable metals are recovered according to the method of Example 3, except that the primary roasting temperature is 360 °C.

[0183] The leaching rates of elements in filtrate 1 are shown in Table 16.1:

[0184] Table 16.1, Element leaching rates

[0185] 。

[0186] The purity of the obtained refined lithium sulfate is 99.7%, and the lithium recovery rate is 92.3%.

[0187] Example 17

[0188] The valuable metals are recovered according to the method of Example 3, except that the secondary roasting temperature is 480 °C.

[0189] The leaching rates of elements in filtrate 1 are shown in Table 17.1:

[0190] Table 17.1, Element leaching rates

[0191] 。

[0192] The purity of the obtained refined lithium sulfate is 99.6%, and the lithium recovery rate is 64.3%.

[0193] Example 18

[0194] The valuable metals are recovered according to the method of Example 3, except that the secondary roasting temperature is 850 °C. The leaching rates of elements in the obtained filtrate 1 are shown in Table 18.1:

[0195] Table 18.1, Element leaching rates

[0196] 。

[0197] The purity of the obtained refined lithium sulfate is 99.7%, and the lithium recovery rate is 78.2%.

[0198] Example 19

[0199] The valuable metals were recovered according to the method of Example 1, except that sulfuric acid was replaced with an equimolar amount of ammonium sulfate. The element leaching rates in the obtained filtrate 1 are shown in Table 19.1:

[0200] Table 19.1, Element Leaching Rates

[0201] 。

[0202] Refined lithium sulfate was obtained, with a purity of 99.7% and a lithium recovery rate of 82.1%.

[0203] Example 20

[0204] The 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:

[0205] Table 20.1, Element Leaching Rates

[0206] 。

[0207] Refined lithium sulfate was obtained, with a purity of 99.6% and a lithium recovery rate of 82.9%.

[0208] Example 21

[0209] The valuable metals were recovered according to the method of Example 1, except that magnesium oxide was replaced with an equimolar amount (calculated based on metal elements) of calcium hydroxide. The element leaching rates in the obtained filtrate 1 are shown in Table 21.1:

[0210] Table 21.1, Element Leaching Rates

[0211] 。

[0212] Refined lithium sulfate was obtained, with a purity of 99.7% and a lithium recovery rate of 99.2%. Calcium hydroxide inhibited the leaching of nickel, cobalt, manganese, and iron, causing them to transfer to the filter residue 1.

[0213] Example 22

[0214] The valuable metals were recovered according to the method of Example 1, except that magnesium oxide was replaced with an equimolar amount (calculated based on metal elements) of aluminum oxide. The element leaching rates in the obtained filtrate 1 are shown in Table 22.1:

[0215] Table 22.1, Element Leaching Rates

[0216] 。

[0217] Refined lithium sulfate is obtained, with a purity of 99.5% and a lithium recovery rate of 99.1%. Alumina inhibits the leaching of nickel, cobalt, manganese, and iron, causing them to transfer to Filter Residue 1.

[0218] Comparative Example 1

[0219] The valuable metals were recovered according to the method of Example 1, except that magnesium oxide was not added. The element leaching rates in the filtrate 1 obtained in step (4) are shown in Table 1-1:

[0220] Table 1-1, Element Leaching Rates

[0221] .

[0222] From the comparison between Table 1-1 and Table 1.2, it can be seen that the leaching rates of nickel, cobalt, manganese, and iron are relatively high, indicating that the amount entering Filter Residue 1 for subsequent recovery is relatively small, which results in the loss of nickel, cobalt, manganese, and iron.

[0223] Comparative Example 2

[0224] The valuable metals were recovered according to the method of Example 2, except that magnesium oxide was replaced with an equimolar amount (calculated based on metal elements) of Ga 2 O 3 , and the element leaching rates in the filtrate 1 are shown in Table 2-1:

[0225] Table 2-1, Element Leaching Rates

[0226] .

[0227] Ga 2 O 3 has a poor inhibitory effect on nickel, cobalt, manganese, and iron, resulting in a large loss of nickel, cobalt, manganese, and iron.

[0228] Comparative Example 3

[0229] The valuable metals were recovered according to the method of Example 2, except that magnesium oxide was replaced with an equimolar amount (calculated based on metal elements) of CaCO 3 , and the element leaching rates in the filtrate 1 are shown in Table 3-1:

[0230] Table 3-1, Element Leaching Rates

[0231] .

[0232] CaCO 3 has a poor inhibitory effect on nickel, cobalt, manganese, and iron, resulting in a large loss of nickel, cobalt, manganese, and iron.

[0233] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within 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, calcium hydroxide and aluminum oxide; 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; The lithium battery black powder includes a first black powder and a second black powder, and the sulfur-containing substance includes sulfuric acid 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; The molar ratio of lithium to sulfuric acid in the first black powder is 1:0.5-1; the molar ratio of lithium to ammonium sulfate in the second black powder is 1:0.55-1; The calcination includes primary calcination and secondary calcination; the temperature of the primary calcination is 280-300°C; the temperature of the secondary calcination is 550-700°C.

2. The method according to claim 1, wherein: The other valuable metals are 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.

4. The method according to claim 3, 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.

1.

5. The method according to claim 1, wherein: The mass concentration of the sulfuric acid is 70-100%; And / or, the average particle size of the ammonium sulfate is 74-245 μm; and / or, the molar ratio of lithium to sulfuric acid in the first black powder is 1:0.52-0.6; And / or, the molar ratio of lithium to ammonium sulfate in the second black powder is 1:0.55-0.

65.

6. The method according to claim 1, wherein: The mass concentration of the sulfuric acid is 80-98%; And / or, the average particle size of the ammonium sulfate is 83-165 μm; and / or, the molar ratio of lithium to sulfuric acid in the first black powder is 1:0.55-0.6; And / or, the molar ratio of lithium to ammonium sulfate in the second black powder is 1:0.55-0.

6.

7. The method according to claim 1, wherein: And / or, the time of the first calcination is 0.5-4h.

8. The method according to claim 1, wherein: The time of the first calcination is 1-2h.

9. The method according to claim 1, wherein: The secondary calcination time is 1-12h.

10. The method according to claim 9, wherein: The secondary calcination time is 3-4h.

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

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

13. 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%; And / or, adding aqueous ammonia to the first filtrate until the pH value is greater than 11.

14. The method according to claim 13, wherein: The concentration of the aqueous ammonia is 15-25%.

15. 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.

16. The method according to claim 15, wherein: The calcination temperature is 550°C.

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