A mixed recovery process for waste old lithium iron phosphate battery powder and waste old ternary lithium battery powder

Abstract

The present application belongs to the technical field of lithium battery recycling, and provides a mixed recycling process for waste lithium iron phosphate battery powder and ternary lithium battery powder. The present application uses waste lithium iron phosphate battery powder and waste ternary lithium battery powder as raw materials, and realizes efficient separation and recovery of valuable metal ions and graphite through processes of roasting and water leaching, one-stage organic acid leaching, two-stage organic acid leaching, acid dissolution, resin copper removal and the like, which is simple and environmentally friendly. The roasting process removes fluorine in the two kinds of waste battery powder, avoids corrosion and damage of fluorine to the autoclave in the subsequent high-pressure impurity removal process, improves the safety factor of the equipment, and increases the safety of the process. In addition, no other impurity removal auxiliary materials need to be added in the process, which greatly reduces the cost investment and increases the economic benefit.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery recycling technology, and specifically relates to a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder. Background Technology

[0002] With the increasing demands for energy conservation, emission reduction, and environmental protection, the new energy vehicle industry has become the mainstream development direction of the automotive industry, and power batteries have become a key required 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 high-energy-output applications such as electric vehicles. With the widespread use of power batteries, the corresponding number of waste lithium-ion batteries has also increased. Waste lithium-ion batteries contain a large number of organic pollutants and heavy metal inorganic compounds that are harmful to human health and the environment; improper disposal can cause serious harm to human health and the environment.

[0003] In 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, while lithium, iron, phosphorus, and graphite in waste lithium iron phosphate batteries can all be recycled and reused. These valuable metals and graphite can be reused in the manufacture of new energy power batteries, possessing extremely high recycling value and economic benefits, while also reducing environmental pollution. 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. Currently, industrial recycling processes for waste ternary lithium batteries and waste lithium iron phosphate batteries mainly use wet leaching to recover valuable metals, which consumes a large amount of chemical reagents and wastes reducing and oxidizing agents, and the recovery rate of valuable metals is not high. Most lithium iron phosphate recycling processes also require hydrogen peroxide as an oxidizing agent, but hydrogen peroxide can overflow during use, increasing safety hazards in the production process.

[0004] Currently, there is limited research on the combined recycling of waste lithium iron phosphate batteries and ternary lithium batteries. Chinese patent CN115321502A discloses a comprehensive recycling process for waste lithium iron phosphate batteries and nickel-cobalt-manganese ternary lithium batteries. This process selectively recovers nickel, cobalt, manganese, lithium, phosphorus, and iron, but does not further separate elements such as aluminum and copper. Therefore, the recycled materials contain a lot of impurities. In addition, oxidants are added during the recycling process, which increases economic costs.

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

[0006] The purpose of this invention is to provide a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder, which comprehensively and efficiently separates and recovers valuable metal elements and graphite from the two types of waste batteries, while simplifying the process flow, increasing process safety, economic benefits and recycling rate, and is beneficial to environmental protection.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The present invention provides a solution for the mixed recycling 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 roasting residue;

[0010] Step 2: The roasted residue is leached with water, and after solid-liquid separation, water leachate and water leachate residue are obtained;

[0011] Step 3: Mix the water leaching residue with a first-stage organic acid solution to perform a first-stage organic acid leaching. After solid-liquid separation, a first-stage acid leaching solution and a first-stage acid leaching residue are obtained.

[0012] Step 4: Mix the first-stage acid leaching residue and the second-stage organic acid solution to perform second-stage organic acid leaching. After solid-liquid separation, the second-stage acid leaching solution and the second-stage acid leaching residue are obtained.

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

[0014] Step 6: Pass the copper-iron salt solution through resin to remove copper, and obtain phosphorus-iron solution and copper-removed resin.

[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. After solid-liquid separation, a solution containing nickel, cobalt, and manganese and iron-aluminum slag are 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℃, and the calcination time is 3-5h.

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

[0020] In some embodiments of the present invention, the organic acid in the first-stage organic acid solution and the second-stage 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-stage organic acid solution is 55%-70%, and the mass concentration of the organic acid in the second-stage 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-to-volume ratio of the water leaching residue and the first-stage organic acid solution is 1 g:(1.5-3) mL, the leaching time of the first-stage organic acid solution and the leaching time of the second-stage organic acid solution are both 5-8 h, and the leaching temperature of the first-stage organic acid solution and the leaching temperature of the second-stage organic acid solution 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 high-pressure leaching temperature is 180-200℃, and the high-pressure leaching time is 3-8h.

[0024] In some embodiments of the present invention, the mass-to-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℃, and the acid dissolution time is 2-5h.

[0025] In some embodiments of the present invention, the resin is at least one of those having an iminodiacetic acid functional group.

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

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

[0028] This invention provides a mixed recycling process for waste ternary lithium battery powder and waste lithium iron phosphate battery powder. The process is simple and environmentally friendly. The roasting process removes fluorine from both types of waste battery powder, avoiding corrosion damage to the autoclave caused by fluorine during subsequent high-pressure impurity removal, thus improving equipment safety and process safety. Furthermore, the process does not require any other impurity removal additives, significantly reducing costs and increasing economic benefits. In addition, by utilizing water leaching, two-stage organic acid leaching, multiple inorganic acid leaching, high-pressure acid leaching, and resin copper removal processes, comprehensive and efficient separation and recovery of valuable metal ions and graphite are achieved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a process flow diagram of a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder provided in Embodiment 1 of the present invention. Detailed Implementation

[0031] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0032] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] This invention provides a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder. The waste lithium iron phosphate battery powder and waste ternary lithium battery powder are mixed and roasted. The high-valence nickel-cobalt-manganese oxide oxide in the waste ternary lithium battery powder and the reducing ferrous iron in the waste lithium iron phosphate battery powder undergo a redox reaction at high temperature. The high-valence nickel-cobalt-manganese oxide is reduced to a low-valence metal oxide, and the ferrous iron in the lithium iron phosphate is oxidized to ferric iron, i.e., iron phosphate. The two battery powders act as each other as oxidizing and reducing agents, reducing the need for other oxidizing or reducing agent additives. The reaction mechanism is as follows:

[0034] LiMeO2+LiFePO4→Li2O+MeO+FePO4

[0035] In addition, the roasting process can remove fluorine from the two types of waste battery powder, avoiding the corrosion and 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 roasted residue is leached with water, and after solid-liquid separation, a water leachate and a water leachate residue are obtained. The water leachate is an acidic solution containing lithium and aluminum. Specifically, the principle is as follows: after the battery powder is mixed and roasted, lithium oxide is obtained. When lithium oxide comes into contact with water, it is converted into lithium hydroxide. Since the lithium hydroxide solution is alkaline, it further dissolves aluminum impurities in the two types of waste battery powder.

[0037] In some embodiments of the present invention, the aqueous leaching solution is mixed with a third inorganic acid solution and reacted to obtain a lithium acid-containing solution and aluminum slag by adjusting the pH value of the solution. Specifically, the inorganic acid in the third inorganic acid solution is at least one selected from formic acid, acetic acid, and citric acid; the mass-to-volume ratio of the aqueous leaching solution to the third inorganic acid solution is 1:(3-4); the reaction time of the aqueous leaching solution and the third inorganic acid solution is 4-5 hours; furthermore, the molar concentration of the inorganic acid in the third inorganic acid solution is 5-6 mol / L.

[0038] In some embodiments of the present invention, since organic acids can only react with nickel cobalt manganese oxides and cannot react with ferric phosphate and copper, ferric 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 ferric phosphate is made more complete.

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

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

[0041] In some embodiments of the present invention, the second-stage acid leaching residue is mixed with a first inorganic acid solution for acid dissolution. After solid-liquid separation, a copper-iron salt solution and graphite slag are obtained. Since graphite is insoluble in acid, the copper-iron salt solution and graphite slag are separated. 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 passed through resin to remove copper, yielding a phosphorus-iron solution and copper-removed resin. The present invention utilizes resin to adsorb copper ions, offering advantages such as being environmentally friendly, recyclable, and reducing the input of auxiliary materials.

[0043] Specifically, the ferric phosphate solution is the stock solution used to produce the ferric phosphate precursor.

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

[0045] In some embodiments of the present invention, the copper-removed resin is dissolved by a fourth inorganic acid 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 amount of the fourth acid solution is 4-5 BV; further, the molar concentration of the inorganic acid in the fourth inorganic acid solution is 4-5 mol / L; and further, the flow rate of the acid solution used to dissolve the copper-containing resin is 1-2 BV / h.

[0046] The entire process of this invention requires only two types of acid solutions and does not require the addition of other impurity removal auxiliary materials, effectively reducing cost input. Through multi-stage process design, it comprehensively and efficiently removes a variety of impurity metal elements and graphite, 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 will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0048] Example 1:

[0049] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder by mixing includes the following steps:

[0050] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 600 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 450°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.001 wt%.

[0051] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 60℃ for 5h, filter, and obtain water leachate and water leach residue.

[0052] (3) Mix the water leaching residue with 60% citric acid solution at a mass-volume ratio of 1g:2ml, leach at 60℃ for 5h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0053] (4) Mix the first stage acid leaching residue with 70% citric acid solution at a mass-volume ratio of 1:1.5, leach at 60°C for 5 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0054] (5) The second-stage acid leaching residue was mixed with 1.4 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2.5 ml, and acid-dissolved at 40 °C for 4 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0055] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:15, and the adsorption flow rate of the copper-iron salt solution was 1 BV / h to obtain phosphate-iron solution.

[0056] (7) A section of acid leaching solution and 15 mol / L sulfuric acid solution were leached at 180°C for 4 hours at a volume ratio of 2.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0057] (8) Mix the water leachate with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, react for 4 hours, and then filter to obtain lithium sulfate solution and aluminum slag.

[0058] (9) Pass a 4 BV 4 mol / L sulfuric acid solution through a copper-removed 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] Example 2:

[0062] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder by mixing includes the following steps:

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

[0064] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:2mL, leach at 80℃ for 6h, filter, and obtain water leachate and water leach residue.

[0065] (3) Mix the water leaching residue with 58% citric acid solution at a mass-volume ratio of 1g:1.5ml, leach at 50℃ for 7h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0066] (4) Mix the first stage acid leaching residue with 65% citric acid solution at a mass-volume ratio of 1:2, leach at 50°C for 7 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0067] (5) The second-stage acid leaching residue was mixed with 1.6 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 4 ml, and acid-dissolved at 50 °C for 5 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0068] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:20, and the adsorption flow rate of the copper-iron salt solution was 2 BV / h to obtain phosphate-iron solution.

[0069] (7) A section of acid leaching solution and 18 mol / L sulfuric acid solution were leached at 200℃ for 7 h at a volume ratio of 3.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0070] (8) The aqueous leachate was mixed with a 6 mol / L sulfuric acid solution at a volume ratio of 1:4. After reacting for 4.5 h, the mixture was filtered to obtain lithium sulfate solution and aluminum slag.

[0071] (9) Pass a 5 BV 5 mol / L sulfuric acid solution through a copper-removed 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] Example 3:

[0075] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder by mixing includes the following steps:

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

[0077] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:3mL, soak the residue in water at 70℃ for 7h, filter, and obtain water leachate and water leachate residue.

[0078] (3) Mix the water leaching residue with 55% citric acid solution at a mass-volume ratio of 1g:3ml, leach at 40℃ for 6h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0079] (4) Mix the first stage acid leaching residue with 68% citric acid solution at a mass-volume ratio of 1:3, leach at 40°C for 6 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0080] (5) The second-stage acid leaching residue was mixed with 1.5 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 3 ml, and acid-dissolved at 45 °C for 3 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0081] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:20, and the adsorption flow rate of the copper-iron salt solution was 2 BV / to obtain phosphate-iron solution.

[0082] (7) A section of acid leaching solution and 17 mol / L sulfuric acid solution were leached at 190°C for 6 hours at a volume ratio of 3:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0083] (8) The water leachate was mixed with 5.5 mol / L sulfuric acid solution at a volume ratio of 1:3.5. After reacting for 5 hours, the mixture was filtered to obtain lithium sulfate solution and aluminum slag.

[0084] (9) Pass a 4BV 5mol / L sulfuric acid solution through a copper-removed resin at a flow rate of 1BV / 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] Example 4:

[0088] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder by mixing includes the following steps:

[0089] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 500 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 400°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.0019 wt%.

[0090] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 90℃ for 3h, filter, and obtain water leachate and water leach residue.

[0091] (3) Mix the water leaching residue with 58% formic acid solution at a mass-volume ratio of 1g:2ml, leach at 50℃ for 8h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0092] (4) Mix the first stage acid leaching residue with 68% formic acid solution at a mass-volume ratio of 1:2, leach at 50°C for 8 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0093] (5) The second-stage acid leaching residue was mixed with 1.5 mol / L nitric acid solution at a mass-volume ratio of 1 g: 2 ml, and acid-dissolved at 40 °C for 2 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0094] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:18, and the adsorption flow rate of the copper-iron salt solution was 1.5 BV / h to obtain phosphate-iron solution.

[0095] (7) A section of acid leaching solution and 17 mol / L sulfuric acid solution were leached at 190°C for 3 h at a volume ratio of 3:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0096] (8) The water leachate was mixed with 5.5 mol / L nitric acid solution at a volume ratio of 1:3.5. After reacting for 4.5 h, the mixture was filtered to obtain lithium nitrate solution and aluminum slag.

[0097] (9) A nitric acid solution with a concentration of 4.5 mol / L and a flow rate of 2 BV / h was passed through the copper-removed resin 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] Example 5:

[0101] A method for recycling waste lithium iron phosphate battery powder and waste ternary lithium battery powder by mixing includes the following steps:

[0102] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 600 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 600°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.001 wt%.

[0103] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 60℃ for 5h, filter, and obtain water leachate and water leach residue.

[0104] (3) Mix the water leaching residue with 70% citric acid solution at a mass-volume ratio of 1g:2ml, leach at 60℃ for 5h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0105] (4) Mix the first stage acid leaching residue with 70% citric acid solution at a mass-volume ratio of 1:1.5, leach at 60°C for 5 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0106] (5) The second-stage acid leaching residue was mixed with 1.4 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2.5 ml, and acid-dissolved at 40 °C for 4 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0107] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:16, and the adsorption flow rate of the copper-iron salt solution was 1 BV / h to obtain phosphate-iron solution.

[0108] (7) A section of acid leaching solution and 15 mol / L sulfuric acid solution were leached at 180°C for 8 hours at a volume ratio of 2.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0109] (8) Mix the water leachate with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, react for 4 hours, and then filter to obtain lithium sulfate solution and aluminum slag.

[0110] (9) Pass a 4 mol / L sulfuric acid solution of 4.5 BV at a flow rate of 1.8 BV / h through the copper-removed resin 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 by mixing includes the following steps:

[0115] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 600 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 450°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.001 wt%.

[0116] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 60℃ for 5h, filter, and obtain water leachate and water leach residue.

[0117] (3) Mix the water leaching residue with 70% citric acid solution at a mass-volume ratio of 1g:2ml, leach at 60℃ for 5h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0118] (4) A section of acid leaching residue was mixed with 1.4 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2.5 ml, and acid-dissolved at 40 °C for 4 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0119] (5) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:15, and the adsorption flow rate of the copper-iron salt solution was 1 BV / h to obtain phosphate-iron solution.

[0120] (6) A section of acid leaching solution and 15 mol / L sulfuric acid solution were leached at 180°C for 4 hours at a volume ratio of 2.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0121] (7) The water leachate and 5 mol / L sulfuric acid solution were mixed at a volume ratio of 1:3. After reacting for 4 hours, the mixture was filtered to obtain lithium sulfate solution and aluminum slag.

[0122] (8) Pass a 4 BV 4 mol / L sulfuric acid solution through a copper-removed 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 by mixing includes the following steps:

[0127] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 600 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 450°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.001 wt%.

[0128] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 60℃ for 5h, filter, and obtain water leachate and water leach residue.

[0129] (3) Mix the water leaching residue with 40% citric acid solution at a mass-volume ratio of 1g:2ml, leach at 60℃ for 5h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0130] (4) Mix the first stage acid leaching residue with 40% citric acid solution at a mass-volume ratio of 1:1.5, leach at 60°C for 5 hours, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0131] (5) The second-stage acid leaching residue was mixed with 1.4 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2.5 ml, and acid-dissolved at 40 °C for 4 h. After filtration, copper-iron salt solution and graphite residue were obtained.

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

[0133] (7) A section of acid leaching solution and 15 mol / L sulfuric acid solution were leached at 180°C for 4 hours at a volume ratio of 2.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0134] (8) Mix the water leachate with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, react for 4 hours, and then filter to obtain lithium sulfate solution and aluminum slag.

[0135] (9) Pass a 4 BV 4 mol / L sulfuric acid solution through a copper-removed 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 A section of 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 by mixing includes the following steps:

[0140] (1) Mix 1 kg of waste lithium iron phosphate battery powder (with lithium, iron, copper and aluminum contents of 3%, 22%, 1%, and 1% respectively) and 600 g of waste ternary lithium battery powder (with lithium, nickel, cobalt, manganese, copper and aluminum contents of 5%, 26%, 5%, 8%, 0.5%, and 0.5% respectively) evenly, put the mixed material into a roasting furnace, and roast at 450°C for 3 hours under a nitrogen atmosphere. After roasting, the fluorine (F) content of the roasting residue is 0.001 wt%.

[0141] (2) Mix the roasted residue with water at a mass-volume ratio of 1g:1.5mL, leach at 60℃ for 5h, filter, and obtain water leachate and water leach residue.

[0142] (3) Mix the water leaching residue with 2 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2 ml, leach at 60 °C for 5 h, filter, and obtain a section of acid leaching residue and a section of acid leaching solution.

[0143] (4) Mix the first stage acid leaching residue with 3 mol / L sulfuric acid solution at a mass-volume ratio of 1:1.5, leach at 60℃ for 5 h, filter, and obtain the second stage acid leaching residue and the second stage acid leaching solution.

[0144] (5) The second-stage acid leaching residue was mixed with 1.4 mol / L sulfuric acid solution at a mass-volume ratio of 1 g: 2.5 ml, and acid-dissolved at 40 °C for 4 h. After filtration, copper-iron salt solution and graphite residue were obtained.

[0145] (6) The PL-930 resin was filled with copper-iron salt solution at a volume ratio of 1:15, and the adsorption flow rate of the copper-iron salt solution was 1 BV / h to obtain phosphate-iron solution.

[0146] (7) A section of acid leaching solution and 15 mol / L sulfuric acid solution were leached at 180°C for 4 hours at a volume ratio of 2.5:1. After filtration, nickel cobalt manganese sulfate solution and iron-aluminum slag were obtained.

[0147] (8) Mix the water leachate with a 5 mol / L sulfuric acid solution at a volume ratio of 1:3, react for 4 hours, and then filter to obtain lithium sulfate solution and aluminum slag.

[0148] (9) Pass a 4 BV 4 mol / L sulfuric acid solution through a copper-removed 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 A section of 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] As can be seen from Tables 1 and 6-9 above, compared with Example 1, Comparative Example 1, the two-stage organic acid leaching process was replaced by a single organic acid leaching. The results showed that the recovery rate of nickel, cobalt, and manganese was reduced, and some incompletely leached nickel, cobalt, and manganese oxides remained in the organic acid leaching residue, resulting in poor separation of nickel, cobalt, and manganese oxides and ferric phosphate. Compared with Example 1, Comparative Example 2 used the same low-concentration organic acid in both stages of organic acid leaching. The results showed that even with two stages of leaching, the low-concentration organic acid was still insufficient for the leaching of nickel, cobalt, and manganese, and would also affect the subsequent separation of ferric phosphate and nickel, cobalt, and manganese oxides. Compared with Example 1, Comparative Example 3 used low-concentration inorganic acid instead of organic acid in the two stages of organic acid leaching. The results showed that during the separation of nickel, cobalt, and manganese and ferric phosphate, inorganic acid would dissolve a large amount of ferric phosphate. The high concentration of iron and phosphorus in the first stage of acid leaching solution would affect the separation effect of nickel, cobalt, and manganese and ferric phosphate.

[0152] Example 1

[0153] To verify the concentration of each metal ion and the total recovery rate in the solutions of each process stage in Examples 1-5 and Comparative Examples 1-3, the specific steps are as follows:

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

[0155] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder, characterized in that, include The following steps: Step 1: Mix and roast waste lithium iron phosphate battery powder and waste ternary lithium battery powder to obtain roasting residue; Step 2: The roasted residue is leached with water, and after solid-liquid separation, water leachate and water leachate residue are obtained; Step 3: Mix the water leaching residue with a first-stage organic acid solution to perform a first-stage organic acid leaching. After solid-liquid separation, a first-stage acid leaching solution and a first-stage acid leaching residue are obtained. Step 4: Mix the first-stage acid leaching residue and the second-stage organic acid solution to perform second-stage organic acid leaching. After solid-liquid separation, the second-stage acid leaching solution and the second-stage acid leaching residue are obtained. Step 5: Mix the second-stage acid leaching residue with the first inorganic acid solution, perform acid dissolution, and after solid-liquid separation, obtain copper-iron salt solution and graphite residue; Step 6: The copper-iron salt solution is subjected to resin to remove copper, resulting in phosphorus-iron solution and copper-removed resin; The mass ratio of the waste lithium iron phosphate battery powder to the waste ternary lithium battery powder is 1:(0.5-0.8); the roasting atmosphere is nitrogen, the roasting temperature is 400-600℃, and the roasting time is 3-5h. The organic acid in the first-stage organic acid solution and the second-stage organic acid solution is independently at least one of formic acid, acetic acid and citric acid.

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

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

4. The mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, characterized in that, The mass-to-volume ratio of the roasted residue to water is 1g:(1.5-3)mL, the water leaching time is 3-7h, and the water leaching temperature is 60-90℃.

5. The mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 3, characterized in that, The organic acid concentration in the first stage organic acid solution is 55%-70%, and the organic acid concentration in the second stage 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.

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

7. The mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 3, 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 high-pressure leaching temperature is 180-200℃, and the high-pressure leaching time is 3-8h.

8. The mixed recycling process of waste lithium iron phosphate battery powder and waste ternary lithium battery powder according to claim 1, characterized in that, The mass-to-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℃, and the acid dissolution time is 2-5h.

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

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