Mixed recovery process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder

Abstract

The invention belongs to the technical field of lithium battery recovery, and provides a mixed recovery process of waste lithium iron phosphate battery powder and ternary lithium battery powder. According to the method, the waste lithium iron phosphate battery powder and the waste ternary lithium battery powder are used as raw materials, efficient separation and recovery of valuable metal ions and graphite are achieved through the processes of roasting, water leaching, first-stage organic acid leaching, second-stage organic acid leaching, acid dissolution, resin copper removal and the like in sequence, the process is simple, and the method is environmentally friendly. Fluorine in the two kinds of waste battery powder is removed in the roasting process, corrosion damage of fluorine to an autoclave in the subsequent high-pressure impurity removal process is avoided, the safety coefficient of equipment is increased, and the safety of the technological process is improved; in addition, no other impurity removal auxiliary materials need to be added in the technological process, so that the cost input is greatly reduced, and the economic benefit is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery recycling, and in particular relates to a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder. Background Art

[0002] With the demand for energy conservation, emission reduction and environmental protection, the new energy vehicle industry has become the mainstream development direction of the automobile industry, and power batteries have become a key demand material in new energy vehicles. Lithium-ion batteries are a widely used type of battery, some of which are designed as high-performance power batteries for large energy output application scenarios such as electric vehicles. With the large-scale application of power batteries, the number of corresponding waste lithium-ion batteries has also increased. Waste lithium-ion batteries contain a large amount of organic pollutants and heavy metal inorganic compounds that are harmful to the human body and the environment. Improper disposal will cause serious harm to human health and the environment.

[0003] Among lithium-ion batteries, ternary lithium batteries and lithium iron phosphate batteries are widely used in power batteries. Waste ternary lithium-ion batteries contain a large amount of recyclable valuable metals and negative electrode graphite. The lithium, iron, phosphorus and graphite in waste lithium iron phosphate can be recycled and reused. These valuable metals and graphite can be reused in the manufacture of new energy power batteries, with extremely high recycling value and economic benefits, and can also reduce environmental pollution problems. Therefore, the recycling and resource utilization of waste lithium-ion batteries will inevitably become a top priority in the development of the new energy industry. At present, the industrial recycling process for waste ternary lithium batteries and waste lithium iron phosphate batteries mainly uses wet leaching to recover valuable metals, which requires a large amount of chemical reagents, and will also cause waste of reducing agents and oxidants, and the recovery rate of valuable metals is not high. Most of the lithium iron phosphate recycling processes also need to select hydrogen peroxide as an oxidant, but hydrogen peroxide will have the problem of bubbling during use, which will increase the safety risks of the production process.

[0004] At present, there are few studies on the joint recycling of waste lithium iron phosphate batteries and ternary batteries. A Chinese patent with publication number CN115321502A discloses a comprehensive recycling process for waste lithium iron phosphate batteries and nickel-cobalt-manganese ternary batteries. This process selectively recovers nickel, cobalt, manganese, lithium, phosphorus and iron elements, and does not further separate elements such as aluminum and copper. Therefore, the recycled materials will contain more impurities. At the same time, oxidants are added during the recycling process, which increases the economic cost.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention includes providing a mixed recovery process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder, which can comprehensively and efficiently separate and recover the valuable metal elements and graphite in the two waste batteries, and at the same time simplify the process flow, increase the process safety, economic benefits and recovery rate, and be beneficial to environmental protection.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The solution provided by the present invention includes a mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0009] Step 1: Mix and roast waste lithium iron phosphate battery powder and waste ternary lithium battery powder to obtain roasted slag;

[0010] Step 2: Leaching the roasted slag with water, and obtaining a water leaching liquid and water leaching slag after solid-liquid separation;

[0011] Step 3: mixing the water leached residue with a section of organic acid solution, performing a section of organic acid leaching, and obtaining a section of acid leaching solution and a section of acid leaching residue after solid-liquid separation;

[0012] Step 4: mixing the first-stage acid leaching residue and the second-stage organic acid solution, performing second-stage organic acid leaching, and obtaining second-stage acid leaching solution and second-stage acid leaching residue after solid-liquid separation;

[0013] Step 5: mixing the second-stage acid leaching residue with the first inorganic acid solution, performing acid dissolution, and obtaining copper-iron salt solution and graphite residue after solid-liquid separation;

[0014] Step 6: removing copper from the copper-iron salt solution through a resin to obtain a ferrophosphorus solution and a resin after copper removal.

[0015] In some embodiments of the present invention, the second-stage acid leaching solution is returned to the first-stage organic acid leaching process for reuse.

[0016] In some embodiments of the present invention, the first acid leaching solution is mixed with the second inorganic acid solution and subjected to high-pressure leaching, and after solid-liquid separation, a solution containing nickel, cobalt, manganese and iron-aluminum slag is obtained.

[0017] In some embodiments of the present invention, the mass ratio of the waste lithium iron phosphate battery powder to the waste ternary lithium battery powder is 1:(0.5-0.8);

[0018] And / or, the calcination atmosphere is a nitrogen atmosphere, the calcination temperature is 400-600° C., and the calcination time is 3-5 hours.

[0019] In some embodiments of the present invention, the mass volume ratio of the roasted slag to water is 1 g: (1.5-3) mL, the water leaching time is 3-7 h, and the water leaching temperature is 60-90°C.

[0020] In some embodiments of the present invention, the organic acid in the first organic acid solution and the second organic acid solution is independently at least one of formic acid, acetic acid and citric acid; the mass concentration of the organic acid in the first organic acid solution is 55%-70%, and the mass concentration of the organic acid in the second organic acid solution is 65%-70%;

[0021] And / or, the first inorganic acid solution is at least one of sulfuric acid, hydrochloric acid, and nitric acid, and the inorganic acid in the second inorganic acid solution is sulfuric acid; the molar concentration of the inorganic acid in the first inorganic acid solution is 1.4-1.6 mol / L, and the molar concentration of the inorganic acid in the second inorganic acid solution is 15-18 mol / L.

[0022] In some embodiments of the present invention, the mass volume ratio of the water leaching residue and the first stage organic acid solution and the mass volume ratio of the first stage acid leaching residue and the second stage organic acid solution are both 1g:(1.5-3)mL, the first stage organic acid leaching time and the second stage organic acid leaching time are both 5-8h, and the first stage organic acid leaching temperature and the second stage organic acid leaching temperature are both 40-60°C.

[0023] In some embodiments of the present invention, the volume ratio of the first acid leaching solution to the second inorganic acid solution is (2.5-3.5):1, the temperature of the high-pressure leaching is 180-200°C, and the time of the high-pressure leaching is 3-8h.

[0024] In some embodiments of the present invention, the mass volume ratio of the second-stage acid leaching residue to the first inorganic acid solution is 1g: (2-4)mL, the acid dissolution temperature is 40-50°C, and the acid dissolution time is 2-5h.

[0025] In some embodiments of the present invention, the resin has at least one of the types of iminodiacetoxy functional groups.

[0026] In some embodiments of the present invention, the volume ratio of the filling volume of the resin to the copper-iron salt solution is 1:(15-20), and the flow rate of the copper-iron salt solution flowing through the resin is 1-2 BV / h.

[0027] Compared with the prior art, the present invention at least has the following beneficial effects:

[0028] The present invention provides a mixed recycling process for waste ternary lithium battery powder and waste lithium iron phosphate battery powder, which is simple and environmentally friendly. In the recycling process, the fluorine in the two waste battery powders is removed during the roasting process, which avoids the corrosion and damage of the autoclave by fluorine in the subsequent high-pressure impurity removal process, improves the safety factor of the equipment, and increases the safety of the process; and no other impurity removal auxiliary materials need to be added in the process flow, which greatly reduces the cost investment and increases the economic benefits; in addition, the process of water leaching, two-stage organic acid leaching, multiple inorganic acid leaching, high-pressure acid leaching and resin copper removal is used to achieve comprehensive and efficient separation and recovery of valuable metal ions and graphite. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A process flow chart of a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0032] The endpoints and any values ​​of the ranges disclosed in the present invention 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, and these numerical ranges should be considered as specifically disclosed in this article.

[0033] In the embodiment of the present invention, a mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder is provided. The waste lithium iron phosphate battery powder and the waste ternary lithium battery powder are mixed and roasted. The high-valent nickel cobalt manganese oxide with oxidation in the waste ternary lithium battery powder and the divalent iron with reduction in the waste lithium iron phosphate battery powder undergo redox reaction under high-temperature roasting. The high-valent nickel cobalt manganese oxide is reduced to a low-valent metal oxide, and the divalent iron in the lithium iron phosphate is oxidized to trivalent iron, i.e., iron phosphate. The two battery powders act as oxidants and reductants to each other, reducing the input of other oxidants or reductants. The reaction mechanism is as follows:

[0034] LiMeO 2 +LiFePO 4 →Li 2 O+MeO+FePO 4

[0035] In addition, the roasting process can also remove fluorine from the two types of waste battery powders, avoiding the corrosion damage of fluorine to the autoclave during the subsequent high-pressure acid leaching process, improving the safety factor of the equipment and increasing the overall safety of the process.

[0036] In some embodiments of the present invention, the calcined slag is subjected to water leaching, and after solid-liquid separation, a water leaching solution and water leaching slag are obtained. The water leaching solution is an acid solution containing lithium and aluminum elements. The specific principle is: lithium oxide is obtained after the battery powder is mixed and calcined, and the lithium oxide is converted into lithium hydroxide after contacting water. Since the lithium hydroxide solution is alkaline, the aluminum impurities in the two waste battery powders are further dissolved.

[0037] In some embodiments of the present invention, the water leaching solution is mixed with a third inorganic acid solution for reaction, and the lithium-containing acid solution and aluminum slag are obtained by adjusting the pH value of the solution. Specifically, the inorganic acid in the third inorganic acid solution is at least one of formic acid, acetic acid and citric acid, the mass volume ratio of the water leaching solution to the third inorganic acid solution is 1:(3-4), the mixing reaction time of the water leaching solution and the third inorganic acid solution is 4-5h, and further, the molar concentration of the inorganic acid in the third inorganic acid solution is 5-6mol / L.

[0038] In some embodiments of the present invention, since the organic acid can only react with nickel-cobalt-manganese oxides but cannot react with iron phosphate and copper, iron phosphate and copper are effectively separated from nickel-cobalt-manganese; by setting up a two-stage organic acid leaching process, the separation of nickel-cobalt-manganese oxides and iron phosphate is more complete.

[0039] In some embodiments of the present invention, the mass concentration of the organic acid in the first organic acid solution is set to 55%-70%, and the mass concentration of the organic acid in the second organic acid solution is set to 65%-70%. The second organic acid leaching concentration is set higher to increase the leaching rate of nickel, cobalt and manganese elements.

[0040] In some embodiments of the present invention, the first-stage acid leaching solution is subjected to high-pressure leaching, and after solid-liquid separation, a nickel-, cobalt-, and manganese-containing solution and iron-aluminum slag are obtained. During the high-pressure leaching process, aluminum ions generate hydrated alunite precipitates under high pressure, and iron ions generate iron oxide precipitates under high pressure, thereby removing aluminum and iron impurities in the solution.

[0041] In some embodiments of the present invention, the second-stage acid leaching residue is mixed with the first inorganic acid solution, acid-dissolved, and solid-liquid separated to obtain copper-iron salt solution and graphite slag. Since graphite is insoluble in acid, copper-iron salt solution and graphite slag are separated, and the copper-iron salt solution contains elements such as phosphorus, iron, and copper.

[0042] In some embodiments of the present invention, the copper-iron salt solution is subjected to a resin to remove copper to obtain a phosphorus iron solution and a resin after copper removal. The present invention utilizes a resin to adsorb copper ions, which has the advantages of being green, environmentally friendly, recyclable, and reducing the input of auxiliary materials.

[0043] Specifically, the ferrophosphide liquid is a stock solution for making an ferrophosphate precursor.

[0044] In some embodiments of the present invention, the resin is a resin containing iminodiacetoxy functional groups.

[0045] In some embodiments of the present invention, the copper-removed resin is subjected to a fourth inorganic acid for analysis and dissolution to obtain a copper-containing acid solution. Specifically, the inorganic acid in the fourth inorganic acid solution is at least one of sulfuric acid, hydrochloric acid and nitric acid, the dosage of the fourth acid solution is 4-5BV, further, the molar concentration of the inorganic acid in the fourth inorganic acid solution is 4-5mol / L, and further, the acid solution flow rate for analyzing the copper-containing resin is 1-2BV / h.

[0046] The entire process of the present invention requires only two types of acid solutions, and does not require the addition of other impurity-removing auxiliary materials, thereby effectively reducing cost investment. Through a multi-stage process design, a variety of impurity metal elements and graphite are comprehensively and efficiently removed, thereby achieving efficient separation and recovery of iron phosphate, nickel, cobalt, manganese, graphite and a variety of metal elements in mixed waste lithium iron phosphate battery powder and waste ternary lithium battery powder.

[0047] The present application is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application.

[0048] Embodiment 1:

[0049] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0050] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 600 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 450° C. for 3 h under a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.001 wt%;

[0051] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 60° C. for 5 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0052] (3) mixing the water leached residue with a 60% citric acid solution at a mass volume ratio of 1 g:2 ml, leaching at 60° C. for 5 h, and filtering to obtain a first-stage acid leached residue and a first-stage acid leached solution;

[0053] (4) mixing the first-stage acid leaching residue with 70% citric acid solution in a mass volume ratio of 1:1.5, leaching at 60° C. for 5 h, filtering, and obtaining the second-stage acid leaching residue and the second-stage acid leaching solution;

[0054] (5) mixing the second-stage acid leaching residue with a 1.4 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2.5 ml, dissolving in acid at 40° C. for 4 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0055] (6) filling the copper-iron salt solution at a volume ratio of 1:15 according to the filling amount of PL-930 resin and the copper-iron salt solution, and the adsorption flow rate of the copper-iron salt solution is 1 BV / h to obtain ferrophosphorus liquid;

[0056] (7) the first-stage acid leaching solution and 15 mol / L sulfuric acid solution were mixed in a volume ratio of 2.5:1, and high-pressure leaching was performed at 180° C. for 4 h, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0057] (8) mixing the water extract with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, reacting for 4 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0058] (9) 4 BV of 4 mol / L sulfuric acid solution is passed through the copper removal resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0059] Table 1

[0060] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 24.69 0 0 0 0 0 4.875 Acid leachate, g / L 0.001 44.57 8.57 10.97 0.967 0.001 0.56 Second stage acid leachate, g / L 0.0013 17.33 3.33 5.34 1.36 0.0009 0.0091 Copper and iron salt solution, g / L 0.0008 0.0004 0.0007 0.0011 77.56 4.64 0.0013 Recovery rate, % 99.69 98.96 99.39 98.88 98.19 98.30 97.98

[0061] Embodiment 2:

[0062] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0063] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3.2%, 21.5%, 1.5% and 1.5% respectively) and 800 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 4%, 25.8%, 4.5%, 6.7%, 0.9% and 0.6% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace and roasted at 550° C. for 5 h under a nitrogen atmosphere. After the roasting, the F content of the roasted slag is 0.0009 wt%;

[0064] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:2 mL, leaching the mixture at 80° C. for 6 h, filtering the mixture to obtain a water leachate and water leachable slag;

[0065] (3) mixing the water leached residue with a 58% citric acid solution at a mass volume ratio of 1 g:1.5 ml, leaching at 50° C. for 7 h, and filtering to obtain a first-stage acid leached residue and a first-stage acid leached solution;

[0066] (4) mixing the first-stage acid leaching residue with 65% citric acid solution in a mass volume ratio of 1:2, leaching at 50° C. for 7 h, and filtering to obtain the second-stage acid leaching residue and the second-stage acid leaching solution;

[0067] (5) mixing the second-stage acid leaching residue with a 1.6 mol / L sulfuric acid solution at a mass volume ratio of 1 g:4 ml, dissolving in acid at 50° C. for 5 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0068] (6) The volume ratio of the filling amount of PL-930 resin to the copper-iron salt solution is 1:20, and the adsorption flow rate of the copper-iron salt solution is 2BV / h to obtain ferrophosphorus liquid;

[0069] (7) the first-stage acid leaching solution and 18 mol / L sulfuric acid solution were leached under high pressure at 200° C. for 7 h in a volume ratio of 3.5:1, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0070] (8) mixing the water extract with a 6 mol / L sulfuric acid solution at a volume ratio of 1:4, reacting for 4.5 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0071] (9) Pass 5 BV of 5 mol / L sulfuric acid solution through the copper removal resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0072] Table 2

[0073] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 23.75 0 0 0 0 0 7.76 Acid leachate, g / L 0.0011 48.69 9.11 10.35 1.12 0.0013 0.91 Second stage acid leachate, g / L 0.0009 15.29 2.11 9.57 1.56 0.0006 0.0086 Copper and iron salt solution, g / L 0.0007 0.0006 0.0011 0.0009 79.13 9.61 0.0009 Recovery rate, % 99.59 98.69 98.33 99.19 98.96 98.69 98.11

[0074] Embodiment 3:

[0075] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0076] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 2.8%, 22.6%, 0.8% and 0.8% respectively) and 700 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 4%, 26.5%, 5.5%, 6.5%, 0.7% and 0.8% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 500° C. for 4 h under a nitrogen atmosphere. After the roasting, the F content of the roasted slag is 0.0012 wt%;

[0077] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:3 mL, immersing the mixture in water at 70° C. for 7 h, and filtering the mixture to obtain a water extract and water leached slag;

[0078] (3) mixing the water leached residue with a 55% citric acid solution at a mass volume ratio of 1 g:3 ml, leaching at 40° C. for 6 h, and filtering to obtain a first-stage acid leached residue and a first-stage acid leached solution;

[0079] (4) mixing the first-stage acid leaching residue with 68% citric acid solution in a mass volume ratio of 1:3, leaching at 40° C. for 6 h, and filtering to obtain the second-stage acid leaching residue and the second-stage acid leaching solution;

[0080] (5) mixing the second-stage acid leaching residue with a 1.5 mol / L sulfuric acid solution at a mass volume ratio of 1 g:3 ml, dissolving in acid at 45° C. for 3 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0081] (6) Filling the solution according to the volume ratio of PL-930 resin to copper-iron salt solution of 1:20, and the adsorption flow rate of the copper-iron salt solution is 2 BV / , to obtain ferrophosphorus solution;

[0082] (7) the first-stage acid leaching solution and 17 mol / L sulfuric acid solution were leached under high pressure at 190° C. for 6 h in a volume ratio of 3:1, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0083] (8) mixing the water extract with a 5.5 mol / L sulfuric acid solution at a volume ratio of 1:3.5, reacting for 5 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0084] (9) 4 BV of 5 mol / L sulfuric acid solution is passed through the copper-removing resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0085] Table 3

[0086] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 14.82 0 0 0 0 0 3.16 Acid leachate, g / L 0.0011 39.68 10.11 8.43 0.66 0.0005 0.86 Second stage acid leachate, g / L 0.0004 12.17 3.34 4.31 0.95 0.0001 0.0053 Copper and iron salt solution, g / L 0.0006 0.0009 0.0005 0.0011 86.36 8.87 0.0010 Recovery rate, % 98.91 99.21 98.96 99.23 98.88 99.35 98.69

[0087] Embodiment 4:

[0088] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0089] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 500 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 400° C. for 3 h in a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.0019 wt%;

[0090] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 90° C. for 3 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0091] (3) mixing the water leached residue with a 58% formic acid solution at a mass volume ratio of 1 g:2 ml, leaching at 50° C. for 8 h, and filtering to obtain a first-stage acid leached residue and a first-stage acid leached solution;

[0092] (4) mixing the first-stage acid leaching residue with 68% formic acid solution in a mass volume ratio of 1:2, leaching at 50° C. for 8 h, and filtering to obtain the second-stage acid leaching residue and the second-stage acid leaching solution;

[0093] (5) mixing the second-stage acid leaching residue with a 1.5 mol / L nitric acid solution at a mass volume ratio of 1 g:2 ml, dissolving in acid at 40° C. for 2 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0094] (6) filling the copper-iron salt solution at a volume ratio of 1:18 according to the filling amount of PL-930 resin and the volume ratio of 1:18, and the adsorption flow rate of the copper-iron salt solution is 1.5 BV / h to obtain ferrophosphorus liquid;

[0095] (7) the first-stage acid leaching solution and 17 mol / L sulfuric acid solution were leached under high pressure at 190° C. for 3 h in a volume ratio of 3:1, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0096] (8) mixing the water extract with a 5.5 mol / L nitric acid solution in a volume ratio of 1:3.5, reacting for 4.5 hours, and filtering to obtain a lithium nitrate solution and aluminum slag;

[0097] (9) A nitric acid solution having a concentration of 4.5 mol / L is passed through the copper-removing resin at a flow rate of 2 BV / h to obtain a copper nitrate solution.

[0098] Table 4

[0099] element Li Ni Co Mn Fe Cu Al Recovery rate, % 98.95 98.01 98.89 98.01 98.96 98.90 99.1

[0100] Embodiment 5:

[0101] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0102] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 600 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 600° C. for 3 h in a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.001 wt%;

[0103] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 60° C. for 5 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0104] (3) mixing the water leached residue with 70% citric acid solution at a mass volume ratio of 1 g:2 ml, leaching at 60° C. for 5 h, filtering, and obtaining a first-stage acid leached residue and a first-stage acid leached solution;

[0105] (4) mixing the first-stage acid leaching residue with 70% citric acid solution in a mass volume ratio of 1:1.5, leaching at 60° C. for 5 h, filtering, and obtaining the second-stage acid leaching residue and the second-stage acid leaching solution;

[0106] (5) mixing the second-stage acid leaching residue with a 1.4 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2.5 ml, dissolving in acid at 40° C. for 4 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0107] (6) filling the copper-iron salt solution at a volume ratio of 1:16 according to the filling amount of PL-930 resin and the copper-iron salt solution, and the adsorption flow rate of the copper-iron salt solution is 1 BV / h to obtain ferrophosphorus liquid;

[0108] (7) the first-stage acid leaching solution and 15 mol / L sulfuric acid solution were mixed in a volume ratio of 2.5:1, and high-pressure leaching was performed at 180° C. for 8 h, and the mixture was filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0109] (8) mixing the water extract with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, reacting for 4 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0110] (9) 4.5 BV of 4 mol / L sulfuric acid solution was passed through the copper removal resin at a flow rate of 1.8 BV / h to obtain a copper sulfate solution.

[0111] Table 5

[0112] element Li Ni Co Mn Fe Cu Al Recovery rate, % 98.91 99.05 98.85 99.06 98.51 98.69 98.96

[0113] Comparative Example 1:

[0114] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0115] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 600 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 450° C. for 3 h under a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.001 wt%;

[0116] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 60° C. for 5 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0117] (3) mixing the water leached residue with 70% citric acid solution at a mass volume ratio of 1 g:2 ml, leaching at 60° C. for 5 h, filtering, and obtaining a first-stage acid leached residue and a first-stage acid leached solution;

[0118] (4) mixing a first-stage acid leaching residue with a 1.4 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2.5 ml, dissolving in acid at 40° C. for 4 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0119] (5) filling the PL-930 resin in a volume ratio of 1:15 to the copper-iron salt solution, and the adsorption flow rate of the copper-iron salt solution is 1 BV / h to obtain ferrophosphorus liquid;

[0120] (6) the first-stage acid leaching solution and 15 mol / L sulfuric acid solution were mixed in a volume ratio of 2.5:1, and high-pressure leaching was performed at 180° C. for 4 h, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0121] (7) mixing the water extract with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, reacting for 4 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0122] (8) 4 BV of 4 mol / L sulfuric acid solution was passed through the copper removal resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0123] Table 6

[0124] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 25.01 0 0 0 0 0 4.905 Acid leachate, g / L 0.001 49.35 9.01 11.39 0.98 0.001 0.60 Copper and iron salt solution, g / L 0.0006 15.46 3.98 5.40 69.63 5.01 0.001 Recovery rate, % 99.61 91.60 90.31 90.61 95.15 96.60 96.02

[0125] Comparative Example 2:

[0126] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0127] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 600 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 450° C. for 3 h under a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.001 wt%;

[0128] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 60° C. for 5 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0129] (3) mixing the water leached residue with a 40% citric acid solution at a mass volume ratio of 1 g:2 ml, leaching at 60° C. for 5 h, and filtering to obtain a first-stage acid leached residue and a first-stage acid leached solution;

[0130] (4) mixing the first-stage acid leaching residue with 40% citric acid solution at a mass volume ratio of 1:1.5, leaching at 60° C. for 5 h, filtering, and obtaining the second-stage acid leaching residue and the second-stage acid leaching solution;

[0131] (5) mixing the second-stage acid leaching residue with a 1.4 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2.5 ml, dissolving in acid at 40° C. for 4 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0132] (6) The volume ratio of the XL-490 resin to the copper-iron salt solution is 1:15, and the adsorption flow rate of the copper-iron salt solution is 1 BV / h to obtain a ferrophosphorus solution;

[0133] (7) the first-stage acid leaching solution and 15 mol / L sulfuric acid solution were mixed in a volume ratio of 2.5:1, and high-pressure leaching was performed at 180° C. for 4 h, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0134] (8) mixing the water extract with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, reacting for 4 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0135] (9) 4 BV of 4 mol / L sulfuric acid solution is passed through the copper removal resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0136] Table 8

[0137] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 25.01 0 0 0 0 0 8.36 Acid leachate, g / L 0.0016 40.13 5.30 6.01 0.91 0.0015 0.83 Second stage acid leachate, g / L 0.0006 11.09 2.01 4.36 1.03 0.0007 0.0098 Copper and iron salt solution, g / L 0.0004 2.01 1.09 2.58 72.36 8.97 0.0008 Recovery rate, % 99.61 95.66 96.07 96.06 97.98 97.96 98.01

[0138] Comparative Example 3:

[0139] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder, comprising the following steps:

[0140] (1) 1 kg of waste lithium iron phosphate battery powder (the contents of lithium, iron, copper and aluminum are 3%, 22%, 1% and 1% respectively) and 600 g of waste ternary lithium battery powder (the contents of lithium, nickel, cobalt, manganese, copper and aluminum are 5%, 26%, 5%, 8%, 0.5% and 0.5% respectively) are mixed evenly, and the mixed materials are placed in a roasting furnace, and roasted at 450° C. for 3 h under a nitrogen atmosphere. After the roasting, the fluorine (F) content of the roasted slag is 0.001 wt%;

[0141] (2) mixing the calcined slag with water in a mass volume ratio of 1 g:1.5 mL, leaching the mixture at 60° C. for 5 h, and filtering the mixture to obtain a water leaching solution and water leaching slag;

[0142] (3) mixing the water leaching residue with a 2 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2 ml, leaching at 60° C. for 5 h, and filtering to obtain a first-stage acid leaching residue and a first-stage acid leaching solution;

[0143] (4) mixing the first-stage acid leaching residue with a 3 mol / L sulfuric acid solution at a mass volume ratio of 1:1.5, leaching at 60° C. for 5 h, and filtering to obtain the second-stage acid leaching residue and the second-stage acid leaching solution;

[0144] (5) mixing the second-stage acid leaching residue with a 1.4 mol / L sulfuric acid solution at a mass volume ratio of 1 g:2.5 ml, dissolving in acid at 40° C. for 4 h, and filtering to obtain a copper-iron salt solution and graphite residue;

[0145] (6) filling the copper-iron salt solution at a volume ratio of 1:15 according to the filling amount of PL-930 resin and the copper-iron salt solution, and the adsorption flow rate of the copper-iron salt solution is 1 BV / h to obtain ferrophosphorus liquid;

[0146] (7) the first-stage acid leaching solution and 15 mol / L sulfuric acid solution were mixed in a volume ratio of 2.5:1, and high-pressure leaching was performed at 180° C. for 4 h, and filtered to obtain a nickel-cobalt-manganese sulfate solution and iron-aluminum slag;

[0147] (8) mixing the water extract with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, reacting for 4 hours, and filtering to obtain a lithium sulfate solution and aluminum slag;

[0148] (9) 4 BV of 4 mol / L sulfuric acid solution is passed through the copper removal resin at a flow rate of 1 BV / h to obtain a copper sulfate solution.

[0149] Table 9

[0150] element Li Ni Co Mn Fe Cu Al Water leachate, g / L 25.89 0 0 0 0 0 5.21 Acid leachate, g / L 0.0015 40.01 7.98 10.55 30.56 3.63 0.91 Second stage acid leachate, g / L 0.0010 20.39 5.51 6.18 35.07 2.91 0.09 Copper and iron salt solution, g / L 0.0008 0.15 0.0056 0.0019 20.39 0.95 0.0014 Recovery rate, % 99.89 98.99 98.81 98.85 98.63 98.09 97.96

[0151] It can be seen from Table 1 and Tables 6-9 above that, compared with Example 1, Comparative Example 1 uses two-stage organic acid leaching processes instead of only one organic acid leaching. The results show that the recovery rate of nickel, cobalt and manganese is reduced, and the residual nickel, cobalt and manganese oxides that are not completely leached in the organic acid leaching slag are poorly separated from nickel, cobalt and manganese oxides; Compared with Example 1, Comparative Example 2 uses the same low-concentration organic acid in both organic acid leaching processes. The results show that even if there are two-stage leaching of the low-concentration organic acid, the leaching of nickel, cobalt and manganese is still insufficient, and the subsequent separation of iron phosphate and nickel, cobalt and manganese oxides will be affected; Compared with Example 1, the organic acid in the two-stage organic acid leaching is replaced by a low-concentration inorganic acid. The results show that in the separation process of nickel, cobalt and manganese and iron phosphate, the inorganic acid will dissolve a large amount of iron phosphate, and the concentration of iron and phosphorus in the first acid leaching solution is too high, which will affect the separation effect of nickel, cobalt and manganese and iron phosphate.

[0152] Effect Example 1

[0153] In order to verify the concentration of each metal ion in each process section solution and the total recovery rate in Examples 1-5 and Comparative Examples 1-3, the specific steps are as follows:

[0154] The Fe and P concentrations in the solution were detected by chemical titration, and the concentrations of other elements were detected by ICP instrument detection; the total recovery rate was calculated as follows: recovery rate = (total mass of metal elements in the solution / mass of metal in the raw material) × 100%.

[0155] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder. It is characterized in that The following steps are involved: Step 1: Mix and roast waste lithium iron phosphate battery powder and waste ternary lithium battery powder to obtain roasted slag; Step 2: Leaching the roasted slag with water, and obtaining a water leaching liquid and water leaching slag after solid-liquid separation; Step 3: mixing the water leached residue with a section of organic acid solution, performing a section of organic acid leaching, and obtaining a section of acid leaching solution and a section of acid leaching residue after solid-liquid separation; Step 4: mixing the first-stage acid leaching residue and the second-stage organic acid solution, performing second-stage organic acid leaching, and obtaining second-stage acid leaching solution and second-stage acid leaching residue after solid-liquid separation; Step 5: mixing the second-stage acid leaching residue with the first inorganic acid solution, performing acid dissolution, and obtaining copper-iron salt solution and graphite residue after solid-liquid separation; Step 6: removing copper from the copper-iron salt solution through resin to obtain ferrophosphorus solution and resin after copper removal.

2. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The second-stage acid leaching liquid is returned to the first-stage organic acid leaching process for reuse.

3. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The first acid leaching solution is mixed with the second inorganic acid solution, subjected to high-pressure leaching and solid-liquid separation, to obtain a solution containing nickel, cobalt, manganese and iron-aluminum slag.

4. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The mass ratio of the waste lithium iron phosphate battery powder to the waste ternary lithium battery powder is 1:(0.5-0.8); And / or, the calcination atmosphere is nitrogen, the calcination temperature is 400-600° C., and the calcination time is 3-5 hours.

5. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The mass volume ratio of the calcined slag to water is 1 g: (1.5-3) mL, the water leaching time is 3-7 h, and the water leaching temperature is 60-90° C.

6. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1 or 2, It is characterized in that The organic acid in the first organic acid solution and the second organic acid solution is independently at least one of formic acid, acetic acid and citric acid; the mass concentration of the organic acid in the first organic acid solution is 55%-70%, and the mass concentration of the organic acid in the second organic acid solution is 65%-70%; And / or, the first inorganic acid solution is at least one of sulfuric acid, hydrochloric acid, and nitric acid, and the inorganic acid in the second inorganic acid solution is sulfuric acid; the molar concentration of the inorganic acid in the first inorganic acid solution is 1.4-1.6 mol / L, and the molar concentration of the inorganic acid in the second inorganic acid solution is 15-18 mol / L.

7. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The mass volume ratio of the water leaching residue to the first stage organic acid solution and the mass volume ratio of the first stage acid leaching residue to the second stage organic acid solution are both 1g:(1.5-3)mL, the first stage organic acid leaching time and the second stage organic acid leaching time are both 5-8h, and the first stage organic acid leaching temperature and the second stage organic acid leaching temperature are both 40-60°C.

8. According to the mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder as described in claim 2, It is characterized in that The volume ratio of the first acid leaching solution to the second inorganic acid solution is (2.5-3.5):1, the temperature of the high-pressure leaching is 180-200°C, and the time of the high-pressure leaching is 3-8h.

9. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The mass volume ratio of the second-stage acid leaching residue to the first inorganic acid solution is 1 g: (2-4) mL, the acid dissolution temperature is 40-50° C., and the acid dissolution time is 2-5 h.

10. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, It is characterized in that The resin has at least one of the types of iminodiacetic acid functional groups, the volume ratio of the filling volume of the resin to the copper iron salt solution is 1: (15-20), and the flow rate of the copper iron salt solution flowing through the resin is 1-2 BV / h.

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