Ternary iron and lithium fully-compatible integrated circulation processing method and system application

Abstract

The invention provides a ternary iron-lithium fully-compatible integrated circulation treatment method and system application, and the method comprises the following steps: mixing lithium iron phosphate black powder and ternary material black powder, carrying out first acid leaching, carrying out primary copper removal on a first acid leaching solution, carrying out a mixed reaction on a copper-removed solution, an oxidizing agent and a crystal inhibition dispersant, and carrying out secondary acid leaching on a second acid leaching solution; first ferrophosphorus slag and dephosphorized liquid are obtained; the crystal inhibition dispersing agent comprises an organic phosphonic acid compound; performing iron and aluminum precipitation on the phosphorus-removed liquid to obtain iron and aluminum slag and iron and aluminum-removed liquid; the first ferrophosphorus slag and the iron-aluminum slag are subjected to alkali dissolution, second ferrophosphorus slag and aluminum-containing liquid are obtained, the second ferrophosphorus slag is subjected to acid dissolution, and ferrophosphorus liquid is obtained; and performing secondary copper removal on the iron and aluminum removed liquid to obtain a pre-extraction liquid and copper slag, and extracting the pre-extraction liquid to obtain a nickel salt solution, a cobalt salt solution and a lithium salt solution. Various wastes such as battery powder, pole piece powder, slurry and the like of the ternary lithium battery and the lithium iron phosphate battery can be fully compatible and integrally recycled.

Description

Technical Field

[0001] This invention belongs to the field of battery recycling technology and relates to an integrated recycling method and system application that is fully compatible with ternary lithium iron phosphate batteries. Background Technology

[0002] Currently, the mainstream power batteries are lithium batteries, including ternary lithium batteries and lithium iron phosphate batteries. Lithium is an expensive and important resource, therefore, it needs to be recycled. Currently, in industry, ternary lithium batteries and lithium iron phosphate batteries are separated and processed separately, not only according to the type of cathode material (ternary or lithium iron phosphate) but also according to the type of waste material (electrode powder, battery powder, or slurry). This increases the complexity of production line design and prevents flexible adjustments to output based on incoming materials, thus hindering equipment utilization.

[0003] Since recycling various types of battery waste has certain similarities, such as the need for acid leaching, heating, and lithium precipitation, it is of great significance to make full use of the similarities in the incoming material recycling process to improve equipment utilization and reduce auxiliary material utilization.

[0004] Based on the above research, there is a need to provide an integrated recycling method that is fully compatible with ternary lithium iron phosphate batteries, which can recycle and process various waste materials such as battery powder, electrode powder, and slurry from ternary lithium batteries and lithium iron phosphate batteries in a fully compatible and integrated manner. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated recycling method and system application that is fully compatible with ternary lithium iron phosphate batteries. The method involves mixing lithium iron phosphate black powder and ternary material black powder to recover not only nickel, cobalt, and lithium, but also iron and phosphorus, resulting in phosphorus-iron liquid. This allows for the integrated recycling and treatment of various waste materials such as battery powder, electrode powder, and slurry from both ternary lithium batteries and lithium iron phosphate batteries.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides an integrated recycling method fully compatible with ternary lithium iron phosphate batteries, the integrated recycling method comprising the following steps:

[0008] (1) Lithium iron phosphate black powder and ternary material black powder are mixed and subjected to a first acid leaching to obtain a first acid leaching solution and a first acid leaching residue;

[0009] (2) The first acid leaching solution in step (1) is subjected to copper removal once to obtain copper removal solution and copper removal slag;

[0010] (3) Mix the copper removal liquid, oxidant and crystal-inhibiting dispersant described in step (2), adjust the pH and react to obtain the first phosphorus iron slag and the phosphorus removal liquid;

[0011] The anti-crystallization dispersant includes organophosphonic acid compounds;

[0012] (4) The dephosphorization liquid obtained in step (3) is subjected to iron and aluminum precipitation to obtain iron and aluminum slag and dephosphorized liquid;

[0013] (5) Dissolve the first phosphorus iron slag in step (3) and the iron aluminum slag in step (4) with alkali to obtain the second phosphorus iron slag and aluminum-containing liquid. Dissolve the second phosphorus iron slag with acid to obtain phosphorus iron liquid.

[0014] The liquid after iron and aluminum removal in step (4) is subjected to a second copper removal to obtain the pre-extraction liquid and copper slag. The pre-extraction liquid is then extracted to obtain nickel salt solution, cobalt salt solution and lithium salt solution.

[0015] When neither the lithium iron phosphate black powder nor the ternary material black powder contains copper, the integrated recycling method does not perform the primary copper removal in step (2) and the secondary copper removal in step (5).

[0016] Lithium battery waste is classified according to its positive electrode active material, including ternary lithium battery waste (the positive electrode active material is mainly lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide) and lithium iron phosphate battery waste. It is also classified according to its form, including powder or slurry, and according to its source, including electrode powder, battery powder, or slurry. It should be noted that the lithium iron phosphate black powder mentioned in this invention refers to battery waste with lithium iron phosphate as the positive electrode active material. It can be obtained from crushed and screened electrodes or from crushed, heat-treated, and screened batteries. Lithium iron phosphate black powder may also include elements such as carbon, aluminum, copper, and fluorine. Similarly, the ternary material black powder mentioned in this invention refers to battery waste with lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide as the positive electrode active material. It can be obtained from crushed and screened electrodes or from crushed, heat-treated, and screened batteries. Ternary material black powder may also include elements such as carbon, iron, copper, and fluorine. When lithium iron phosphate black powder originates from the electrode sheet, it can be called lithium iron phosphate electrode black powder; when lithium iron phosphate black powder originates from the battery, it can be called lithium iron phosphate battery black powder.

[0017] This invention involves mixing lithium iron phosphate black powder and ternary material black powder, followed by a first acid leaching and a first copper removal process. Then, the copper-removed solution, oxidant, and crystal-inhibiting dispersant are mixed and reacted. The oxidant oxidizes ferrous iron to ferric iron, and the following reaction occurs: Fe 3+ +PO4 3- →FePO4↓, where the anti-crystallization dispersant is an organophosphonic acid compound with good hydration properties, and the phosphonate ion can react with Fe 3+ The complex occupies the coordination layer, and due to the large number of strongly hydrating groups linked to phosphonate groups, it can prevent Fe... 3+ Further with PO4 3-The orderly arrangement inhibits crystal nucleus growth and also benefits phosphonate / PO4. 3- with Fe 3+ The complexes are dispersed in water to avoid agglomeration and sedimentation. Then, the dephosphorized liquid is subjected to iron and aluminum precipitation to obtain iron-aluminum slag and iron-aluminum-removed liquid. The first iron-phosphorus slag and iron-aluminum slag are alkali-dissolved to obtain the second iron-phosphorus slag and aluminum-containing liquid. The aluminum-containing liquid can be used to prepare aluminum products (polyaluminum chloride, alumina, etc.). The second iron-phosphorus slag is acid-dissolved to obtain iron-phosphorus liquid and hydrated iron-phosphorus slag. The iron-phosphorus liquid can be used to prepare anhydrous iron phosphate. Finally, the dephosphorized liquid undergoes secondary copper removal and extraction steps to recover nickel salt solution, cobalt salt solution and lithium salt solution, thus realizing the recovery of nickel, cobalt and lithium.

[0018] When neither the lithium iron phosphate black powder nor the ternary material black powder contains copper, the integrated recycling method does not perform the first copper removal in step (2) and the second copper removal in step (5), and directly performs the first acid leaching solution in step (1) in step (3), and directly extracts the solution after iron and aluminum removal in step (4).

[0019] Preferably, the leaching endpoint pH of the first acid leaching in step (1) is 0.5 to 2, for example, it can be 0.5, 1.0, 1.5 or 2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the temperature of the first acid leaching in step (1) is below 60°C, for example, it can be 55°C, 50°C, 45°C, 40°C, 35°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the amount of acid used in the first acid leaching step (1) is 1.8 to 2.5 times the theoretical amount, for example, it can be 1.8 times, 2 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times or 2.5 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] In step (1) of the present invention, the acid used for the first acid leaching can be sulfuric acid. The theoretical amount of acid used for the first acid leaching is calculated based on the total amount of lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on the total content of nickel ions, cobalt ions and manganese ions) in the raw materials.

[0023] Preferably, the concentration of acid used in the first acid leaching in step (1) is 1.5 mol / L to 3.5 mol / L, for example, it can be 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L or 3.5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the amount of oxidant used in the first acid leaching step (1) is 1.2 to 1.8 times the theoretical amount, for example, it can be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 or 1.8 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] In step (1) of the present invention, the theoretical amount of oxidant used in the first acid leaching is calculated based on the total amount of lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on the total content of nickel ions, cobalt ions and manganese ions) in the raw materials.

[0026] The oxidant used in the first acid leaching of this invention can be hydrogen peroxide, and the reaction that occurs in the first acid leaching is as follows: LiNi x Co y Mn 1-x-y O2 reacts with acid and hydrogen peroxide to form Li. + Ni 2+ Co 2+ Mn 2+ In the presence of H2O, LiFePO4 precipitates under the action of acid and hydrogen peroxide, forming FePO4 precipitate and Li + and H2O, wherein the first acid leaching solution contains H + Ni 2+ Co 2+ Mn 2+ Li + And impurity ions such as Cu, Al, and Fe.

[0027] Preferably, the first acid leaching time in step (1) is 3h to 5h, for example, it can be 3h, 3.5h, 4h, 4.5h or 5h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, in step (1), the first acid leaching residue is further subjected to a second acid leaching step to obtain graphite residue and a second acid leaching solution, and the second acid leaching solution is reused as acid solution in the first acid leaching process in step (1).

[0029] The first acid leaching residue obtained by the present invention is further subjected to a second acid leaching step, and the second acid leaching solution obtained from the second acid leaching can be reused in the first acid leaching process.

[0030] Preferably, the second acid leaching is carried out using sulfuric acid (concentration of 1.5 mol / L to 3.5 mol / L, for example, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L or 3.5 mol / L) and sodium thiosulfate (as an oxidizing agent).

[0031] Preferably, the temperature of the second acid leaching is below 60°C, for example, it can be 55°C, 50°C, 45°C, 40°C, 35°C or 30°C, and the time is 7h to 9h, for example, it can be 7h, 7.5h, 8h, 8.5h or 9h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, iron powder is used for the primary copper removal in step (2).

[0033] The reaction involved in the primary copper removal in step (2) of this invention is as follows: 2Fe 3+ +Fe→3Fe 2+ Cu 2+ +Fe→Fe 2+ +Cu.

[0034] Preferably, the amount of iron powder added is 1.2 to 1.4 times the molar amount of copper ions in the first acid leaching solution, for example, it can be 1.2 times, 1.25 times, 1.3 times, 1.35 times or 1.4 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the temperature for the first copper removal in step (2) is below 60°C, for example, it can be 55°C, 50°C, 45°C, 40°C, 35°C or 30°C, and the reaction time is 4h to 6h, for example, it can be 4h, 4.5h, 5h, 5.5h or 6h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, in step (3), when mixing the copper-removed liquid, oxidant, and crystal-inhibiting dispersant described in step (2), a protective co-solvent is also added.

[0037] This invention further incorporates a protective co-solvent, which possesses excellent water solubility and plays a stabilizing role for phosphonate / PO4 groups. 3- with Fe 3+ The protective cosolubilities act as a hydration layer, thereby inhibiting further aggregation and growth of the complexes; these protective cosolubilities, upon dissolving in water, form a thick hydration layer, allowing them to interact with phosphonate / PO4. 3- with Fe 3+ The complex has a weak affinity and exhibits repulsive forces (steric hindrance), making the phosphonate / PO4 complex more difficult to bind. 3- with Fe 3+ The complexes tend to remain in the bulk solution, thus making the phosphonate / PO4 complex more likely to remain in the bulk solution. 3- with Fe 3+ The concentration of protective cosolvent is low in the region near the complex, meaning that the concentration of water molecules is relatively high in the region near the complex, thus achieving a stabilizing effect.

[0038] Preferably, the protective cosolvent comprises carbohydrate compounds and / or polyols.

[0039] Preferably, the carbohydrate compound includes sucrose and / or trehalose.

[0040] Preferably, the polyol comprises glycerol and / or sorbitol.

[0041] Preferably, the amount of the protective cosolvent added is 6wt% to 10wt% of the amount of the anti-crystallization dispersant added, for example, it can be 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0042] Preferably, the crystal-inhibiting dispersant in step (3) is added at a phosphorus mass percentage of 25wt% to 35wt% of the total phosphorus mass percentage in the copper-removed liquid. For example, it can be 25wt%, 30wt%, or 35wt%, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the organophosphonic acid compound in step (3) includes any one or a combination of at least two of 2-phosphonobutane-1,2,4-tricarboxylic acid, sodium glycerophosphate, sodium glucose-6-phosphate, or sodium fructose-6-phosphate.

[0044] Preferably, the amount of oxidant added in step (3) is 1.1 to 1.3 times the theoretical amount, for example, it can be 1.1 times, 1.15 times, 1.2 times, 1.25 times or 1.3 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the oxidant in step (3) includes hydrogen peroxide.

[0046] Preferably, the pH adjustment to 1-3 in step (3) (by adding liquid alkali) can be, for example, 1, 1.5, 2, 2.5 or 3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] Preferably, the temperature of the reaction in step (3) is 30℃ to 60℃, for example, 30℃, 40℃, 50℃ or 60℃, and the time is 1h to 4h, for example, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, the pH of the dephosphorization solution in step (3) is adjusted to 5-8 (by adding liquid alkali) to precipitate iron and aluminum. For example, it can be 5, 6, 7 or 8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] In this invention, iron and aluminum are precipitated at pH values ​​above 5, and Al is precipitated as hydroxide.

[0050] Preferably, the temperature for immersing iron and aluminum in step (4) is 20℃ to 40℃, for example, 20℃, 25℃, 30℃, 35℃ or 40℃, and the reaction time is 1h to 3h, for example, 1h, 1.5h, 2h, 2.5h or 3h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] Preferably, after the iron and aluminum are removed in step (4), the mixture is allowed to stand for 3 to 5 hours, for example, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, and then solid-liquid separation is performed to obtain iron and aluminum slag and liquid after iron and aluminum removal.

[0052] Preferably, the endpoint pH of the alkaline dissolution (e.g., using liquid alkali) in step (5) is 12 to 14, for example, it can be 12, 12.5, 13, 13.5 or 14, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, the temperature of the alkali dissolution in step (5) is 60℃~80℃, for example, 60℃, 65℃, 70℃, 75℃ or 80℃, and the time is 2h~4h, for example, 2h, 2.5h, 3h, 3.5h or 4h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] Preferably, the endpoint pH of the acid dissolution (e.g., using phosphoric acid and / or sulfuric acid) in step (5) is below 0.5, for example, it can be 0.5, 0.4, 0.3, 0.2 or 0.1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] Preferably, the acid dissolution temperature in step (5) is 30℃~50℃, for example, 30℃, 40℃ or 50℃, and the time is 5h~7h, for example, 5h, 5.5h, 6h, 6.5h or 7h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0056] Preferably, the ferric phosphate solution in step (5) is used to prepare anhydrous ferric phosphate.

[0057] Preferably, sodium sulfide is used for the secondary copper removal in step (5).

[0058] Preferably, the extractant used in step (5) includes P507 and C272.

[0059] Preferably, the Ni recovery rate of the method is ≥99.8%, for example, it can be 99.8%, 99.82%, 99.84%, 99.86%, 99.88% or 99.9%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] Preferably, the Co recovery rate of the method is ≥99.8%, for example, it can be 99.8%, 99.82%, 99.84%, 99.86%, 99.88% or 99.9%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] Preferably, the Li recovery rate of the method is ≥94%, for example, it can be 94%, 94.5%, 95%, 95.5% or 96%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0062] Preferably, the slag discharge rate of the method is ≤1.5%, for example, it can be 1.5%, 1.25%, 1.0%, 0.75%, 0.5% or 0.25%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0063] This invention obtains hydrated ferrophosphorus slag while obtaining ferrophosphorus liquid. The hydrated ferrophosphorus slag is a solid waste. The slag discharge rate refers to the P content in the hydrated ferrophosphorus slag divided by the P content in the mixed black powder, and then multiplied by 100%.

[0064] Secondly, the present invention provides a system application of the integrated recycling treatment method as described in the first aspect. The system application refers to the system applied in the integrated recycling treatment method. The system includes an acid leaching module, a purification module, a phosphorus iron slag treatment module, and a solvent extraction module.

[0065] The acid leaching module includes a mixing and pulping unit, a first acid leaching unit, and a second acid leaching unit. The mixing and pulping unit includes a black powder storage silo, a screw feeder, a belt conveyor, a mixer, and a pulping tank. Both the first and second acid leaching units include an acid leaching reactor, a metering pump, a filter press, and a filtrate storage tank. The first acid leaching unit also includes a screw conveyor for conveying filter residue to the second acid leaching unit. The second acid leaching unit also includes a graphite residue baling machine.

[0066] The impurity removal module includes a copper removal unit, a phosphorus removal unit, an iron and aluminum removal unit, and a deep copper removal unit. The copper removal unit includes a copper removal reactor, an iron powder feeder, a filter press, a copper removal post-liquid storage tank, and an iron-copper slag baler. The phosphorus removal unit includes a phosphorus removal reactor, a metering pump, a filter press, a phosphorus removal post-liquid storage tank, and a belt conveyor. The iron and aluminum removal unit includes an iron and aluminum removal reactor, a metering pump, a thickener, a filter press, an iron and aluminum removal post-liquid storage tank, and a belt conveyor. The deep copper removal unit includes a sulfidation reactor, a metering pump, a filter press, a precision filter, and a pre-extraction liquid storage tank.

[0067] The phosphorus iron slag treatment module includes an alkali dissolution unit and an acid dissolution unit; the alkali dissolution unit includes a feeder, an alkali dissolution reactor, a metering pump, a filter press, and an aluminum-containing liquid storage tank; the acid dissolution unit includes an acid dissolution reactor, a metering pump, a centrifuge, and a phosphorus iron liquid storage tank.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] This invention involves mixing lithium iron phosphate black powder and ternary material black powder, wherein a crystal-inhibiting dispersant is added during phosphorus removal to react with Fe. 3+ The complex occupies the coordination layer, and due to the large number of strongly hydrating groups linked to phosphonate groups, it can prevent Fe... 3+ Further with PO4 3- The orderly arrangement inhibits crystal nucleus growth and also benefits phosphonate / PO4. 3- with Fe 3+ The complexes are dispersed in water to avoid agglomeration and sedimentation. Then, the dephosphorized liquid is subjected to iron and aluminum precipitation to obtain iron-aluminum slag and iron-aluminum-removed liquid. The first iron-phosphorus slag and iron-aluminum slag are alkali-dissolved to obtain the second iron-phosphorus slag and aluminum-containing liquid. The aluminum-containing liquid can be used to prepare aluminum products (polyaluminum chloride, alumina, etc.). The second iron-phosphorus slag is acid-dissolved to obtain iron-phosphorus liquid and hydrated iron-phosphorus slag. The iron-phosphorus liquid can be used to prepare anhydrous iron phosphate. Finally, the dephosphorized liquid undergoes secondary copper removal and extraction steps to recover nickel salt solution, cobalt salt solution and lithium salt solution, thus realizing the recovery of nickel, cobalt and lithium. Attached Figure Description

[0070] Figure 1 This is a flowchart of the method described in Embodiment 1 of the present invention. Detailed Implementation

[0071] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0072] Example 1

[0073] This embodiment provides an integrated recycling method fully compatible with ternary lithium iron phosphate batteries. The flowchart of the method is as follows: Figure 1 As shown, it includes the following steps:

[0074] (1) The black powder of lithium iron phosphate battery and black powder of ternary battery are mixed evenly in the mixing and pulping unit to obtain mixed black powder. The mixing and pulping unit includes a black powder storage silo, a screw feeder, a belt conveyor, a mixer and a pulping tank. The composition of the mixed black powder is shown in Table 1. The mixed black powder and deionized water are pulped at a solid-liquid ratio of 1g:2mL. The mixture is pumped into the acid leaching reactor of the first acid leaching unit at a concentration of 20wt% hydrogen peroxide solution. Then, the second acid leaching solution is pumped in by a metering pump for the first acid leaching. The temperature is maintained at 40℃ for 4h. The solid and liquid are separated in a filter press. After washing, the first acid leaching solution and the first acid leaching residue are obtained. The first acid leaching solution is stored in a filtrate storage tank. The first acid leaching residue is transported to the second acid leaching unit by a screw conveyor. Sulfuric acid and sodium thiosulfate are added for the second acid leaching. The temperature is maintained at 40℃ for 8h. After solid-liquid separation, the second acid leaching solution and graphite residue are obtained. The graphite residue is packaged in a graphite residue baling machine.

[0075] The sulfuric acid concentration is 2 mol / L (hydrogen ion concentration), and the concentration of the second acid leaching solution is 1.7 mol / L (hydrogen ion concentration); the final pH value of the first acid leaching is 0.5; the amount of the second acid leaching solution added is 1.8 times the theoretical amount needed to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the total amount of hydrogen peroxide added is 1.5 times the theoretical amount needed to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the mass ratio of sulfuric acid added during the second acid leaching to the mass of the first acid leaching residue is 10 mL: 1 g; the mass of sodium thiosulfate is 1 times the mass of the first acid leaching residue.

[0076] (2) In step (1), the first acid leaching solution enters the impurity removal module for impurity removal. The impurity removal module includes a copper removal unit, a phosphorus removal unit, an iron and aluminum removal unit, and a deep copper removal unit. First, it enters the copper removal unit. The first acid leaching solution from step (1) is added to the copper removal reactor. Then, iron powder is added using an iron powder feeder. The molar amount of iron powder added is equal to the Cu content in the first acid leaching solution. 2+ The reaction was carried out at 1.3 times the molar amount and the temperature was maintained at 40℃ for 5 hours. After solid-liquid separation by a filter press, iron-copper slag and copper-removed liquid were obtained. The copper-removed liquid was stored in a copper-removed liquid storage tank, and the iron-copper slag was packaged by an iron-copper slag baling machine.

[0077] (3) Add the copper-removed liquid from step (2) to the dephosphorization reactor. Add hydrogen peroxide, crystal-inhibiting dispersant and protective cosolvent with a concentration of 20wt% to the copper-removed liquid from step (2) through a metering pump. Then add liquid alkali to adjust the pH to 1.5. Heat to 60℃ and stir for 3 hours. After solid-liquid separation by a filter press, the first phosphorus iron slag and the dephosphorized liquid are obtained. The dephosphorized liquid is stored in the dephosphorized liquid storage tank. The first phosphorus iron slag is transported to the alkali dissolution reactor in step (5) by a belt conveyor.

[0078] The crystal-inhibiting dispersant is sodium glycerophosphate, and it is added at a phosphorus content of 30 wt% of the total phosphorus content in the copper-removed solution. The protective co-solvent is sucrose, and its addition amount is 8 wt% of the amount of the crystal-inhibiting dispersant. The amount of hydrogen peroxide added is theoretically sufficient to remove all Fe... 2+ Oxidized to Fe 3+ 1.2 times;

[0079] (4) Add the dephosphorized liquid from step (3) to the iron-aluminum precipitation reactor, and continue to add liquid alkali to adjust the pH to 7 for iron precipitation. Stir at 30°C for 2 hours, let stand for 4 hours, and then separate the solid and liquid through a filter press to obtain iron-aluminum slag and iron-aluminum slag. The iron-aluminum slag is stored in the iron-aluminum slag storage tank, and the iron-aluminum slag is transported to the alkali dissolution reactor in step (5) by a belt conveyor.

[0080] (5) In the alkaline dissolution reactor, the first phosphorus iron slag from step (3), the iron aluminum slag from step (4) and deionized water are slurried at a solid-liquid ratio of 1g:2mL. Then, liquid alkali is added through a metering pump for alkaline dissolution. The alkaline dissolution temperature is 70℃ and the time is 3h. The pH at the end of the alkaline dissolution is 13. After solid-liquid separation by a filter press, the second phosphorus iron slag and aluminum-containing liquid are obtained by washing. The aluminum-containing liquid is stored in an aluminum-containing liquid storage tank.

[0081] (6) Add the second phosphorus iron slag from step (5) to the acid dissolution reactor, and then add phosphoric acid and sulfuric acid through a metering pump for acid dissolution. Maintain the temperature at 40°C and dissolve for 6 hours. The final pH of the acid dissolution is 0.37. After solid-liquid separation by centrifuge, phosphorus iron liquid and hydrated phosphorus iron slag are obtained. The phosphorus iron liquid is stored in the phosphorus iron liquid storage tank for subsequent preparation of anhydrous ferric phosphate. The hydrated phosphorus iron slag is solid waste.

[0082] The amount of phosphoric acid added is based on a ratio of 1.2:1 between the total molar amount of phosphorus in the second phosphorus-iron slag and the total molar amount of phosphorus in the phosphoric acid, and the molar amount of iron in the second phosphorus-iron slag.

[0083] (7) Add the iron and aluminum removal liquid from step (4) to the sulfidation reactor, and then add sodium sulfide for deep copper removal. After solid-liquid separation by a filter press and a precision filter, the pre-extraction liquid and copper slag (copper sulfide) are obtained. The pre-extraction liquid is stored in the pre-extraction liquid storage tank. The amount of sodium sulfide added is 1.2 times the amount used to theoretically convert all the copper in the iron and aluminum removal liquid into copper sulfide.

[0084] (8) Add sulfuric acid to adjust the pH of the pre-extraction liquid to 3.5. Use sodium soap P204 (saponification rate 40%) to extract the pre-extraction liquid. The diluent is sulfonated kerosene. The mass ratio of sodium soap P204 to diluent is 30%:70%. The number of extraction stages is 8, the number of washing stages is 6, the number of back-extraction stages is 7, and the number of anti-iron stages is 2. The washing acid is dilute sulfuric acid (hydrogen ion concentration is 0.05mol / L), and the back-extraction acid is sulfuric acid (hydrogen ion concentration is 2mol / L). Manganese-containing back-extraction liquid and raffinate are obtained.

[0085] The pH of the raffinate was adjusted to 4.8 by adding liquid alkali. Then, the raffinate was extracted with sodium soap P507 (saponification rate of 25%). The diluent was sulfonated kerosene. The mass ratio of sodium soap P507 to diluent was 30%:70%. The number of extraction stages was 8, the number of washing stages was 5, the number of anti-iron stages was 2, and the number of back-extraction stages was 5. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 4 mol / L). Nickel-lithium raffinate and cobalt-containing solution were obtained.

[0086] Sulfuric acid was added to adjust the pH of the cobalt-containing solution to 4. Then, the cobalt-containing solution was extracted using C272 ammonia soap (saponification rate of 20%). The diluent was sulfonated kerosene. The mass ratio of C272 ammonia soap to diluent was 30%:70%. The extraction stage consisted of 8 stages, the washing stage of 5 stages, the back-extraction stage of 5 stages, and the anti-iron stage of 2 stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A cobalt sulfate solution was obtained. After degreasing, a cobalt salt solution was obtained, which is the purified cobalt sulfate solution.

[0087] The pH of the nickel-lithium raffinate was adjusted to 8 by adding liquid alkali. Then, sodium soap C272 (saponification rate 25%) was used to extract the nickel-lithium raffinate. The diluent was sulfonated kerosene. The mass ratio of sodium soap C272 to diluent was 30%:70%. There were 8 extraction stages, 5 washing stages, 5 back-extraction stages, and 2 anti-iron stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A nickel sulfate solution was obtained. After degreasing, a nickel salt solution was obtained, which was then purified. The lithium-containing raffinate was degreased to obtain a lithium salt solution, which was then sent to the lithium salt workshop.

[0088] Table 1

[0089] element Li Fe P Ni Co Mn Al Cu content(%) 3.01 10.02 5.41 9.01 2.59 4.02 2.18 1.52

[0090] The system used in the above method includes an acid leaching module, an impurity removal module, a phosphorus and iron slag treatment module, and a solvent extraction module; the acid leaching module includes a mixing and pulping unit, a first acid leaching unit, and a second acid leaching unit; the mixing and pulping unit includes a black powder storage silo, a screw feeder, a belt conveyor, a mixer, and a pulping tank; both the first and second acid leaching units include an acid leaching reactor, a metering pump, a filter press, and a filtrate storage tank; the first acid leaching unit also includes a screw conveyor for conveying filter residue to the second acid leaching unit; the second acid leaching unit also includes a graphite slag baling machine; the impurity removal module includes a copper removal unit, a phosphorus removal unit, an iron and aluminum removal unit, and a deep copper removal unit; the copper removal unit includes... The system includes a copper removal reactor, an iron powder feeder, a filter press, a copper removal post-removal liquid storage tank, and an iron-copper slag baling machine; the phosphorus removal unit includes a phosphorus removal reactor, a metering pump, a filter press, a phosphorus removal post-removal liquid storage tank, and a belt conveyor; the iron-aluminum removal unit includes an iron-aluminum sedimentation reactor, a metering pump, a thickener, a filter press, an iron-aluminum removal post-removal liquid storage tank, and a belt conveyor; the deep copper removal unit includes a sulfidation reactor, a metering pump, a filter press, a precision filter, and a pre-extraction liquid storage tank; the phosphorus-iron slag treatment module includes an alkali dissolution unit and an acid dissolution unit; the alkali dissolution unit includes a feeder, an alkali dissolution reactor, a metering pump, a filter press, and an aluminum-containing liquid storage tank; the acid dissolution unit includes an acid dissolution reactor, a metering pump, a centrifuge, and a phosphorus-iron liquid storage tank.

[0091] Example 2

[0092] This embodiment provides an integrated recycling method fully compatible with ternary lithium iron phosphate batteries. The system used in this method does not contain a copper removal unit or a deep copper removal unit; all other aspects are the same as the system used in the method described in Embodiment 1. The method includes the following steps:

[0093] (1) After mixing lithium iron phosphate electrode black powder and ternary electrode black powder evenly, a mixed black powder is obtained. The composition of the mixed black powder is shown in Table 2. The mixed black powder and deionized water are mixed into a slurry at a solid-liquid ratio of 1g:2mL. The slurry is then pumped into an acid leaching reactor with a 20wt% hydrogen peroxide solution. Then, the first sulfuric acid is pumped in for the first acid leaching. The temperature is maintained at 30℃ for 5h. After solid-liquid separation and washing, the first acid leaching solution and the first acid leaching residue are obtained. The second sulfuric acid and sodium thiosulfate are added to the first acid leaching residue for the second acid leaching. The temperature is maintained at 30℃ for 9h. After solid-liquid separation, the second acid leaching solution and carbon-containing residue are obtained.

[0094] Wherein, the concentration of the second sulfuric acid is 3.5 mol / L (referring to hydrogen ion concentration), and the concentration of the first sulfuric acid is 3.5 mol / L (referring to hydrogen ion concentration); the final pH value of the first acid leaching is 0.5; the amount of the first sulfuric acid added is 2.2 times the theoretical amount required to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the total amount of hydrogen peroxide added is 1.8 times the theoretical amount required to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the mass ratio of the amount of the second sulfuric acid added during the second acid leaching to the mass of the first acid leaching residue is 10 mL: 1 g; the mass of the sodium thiosulfate is 1 times the mass of the first acid leaching residue;

[0095] (2) Add hydrogen peroxide, crystal-inhibiting dispersant and protective cosolvent with a concentration of 20wt% to the first acid leaching solution in step (1), then add liquid alkali to adjust the pH to 3, raise the temperature to 60℃ and stir for 1 hour, and obtain the first phosphorus iron slag and phosphorus-removed liquid after solid-liquid separation.

[0096] The crystal-inhibiting dispersant is 2-phosphonobutane-1,2,4-tricarboxylic acid, and is added at a phosphorus content of 35 wt% of the total phosphorus content in the first acid leaching solution. The protective co-solvent is glycerol, and its addition amount is 6 wt% of the amount of the crystal-inhibiting dispersant. The amount of hydrogen peroxide added is theoretically sufficient to remove all Fe... 2+ Oxidized to Fe 3+ 1.1 times;

[0097] (3) Add liquid alkali to the dephosphorized liquid in step (2) to adjust the pH to 8 for iron and aluminum precipitation. Stir at 40°C for 1 hour and let stand for 3 hours. Separate the solid and liquid to obtain iron and aluminum slag and dephosphorized liquid.

[0098] (4) The first phosphorus iron slag in step (2), the iron aluminum slag in step (3) and deionized water are slurried at a solid-liquid ratio of 1g:2mL. Then, liquid alkali is added for alkali dissolution. The alkali dissolution temperature is 60℃ and the time is 4h. The pH at the end of the alkali dissolution is 12. After solid-liquid separation and washing, the second phosphorus iron slag and aluminum-containing liquid are obtained.

[0099] (5) Add phosphoric acid and sulfuric acid to the second phosphorus iron slag in step (4) for acid dissolution, maintain the temperature at 50°C, dissolve for 5 hours, and the final pH of acid dissolution is 0.5. After solid-liquid separation, phosphorus iron liquid and hydrated phosphorus iron slag are obtained. The phosphorus iron liquid is used for subsequent preparation of anhydrous ferric phosphate, and the hydrated phosphorus iron slag is solid waste.

[0100] The amount of phosphoric acid added is based on a ratio of 1.2:1 between the total molar amount of phosphorus in the second phosphorus-iron slag and the total molar amount of phosphorus in the phosphoric acid, and the molar amount of iron in the second phosphorus-iron slag.

[0101] (6) Add sulfuric acid to the iron and aluminum removal solution in step (3) to adjust the pH of the pre-extraction solution to 3.5. Use sodium soap P204 (saponification rate of 40%) to extract the pre-extraction solution. The diluent is sulfonated kerosene. The mass ratio of sodium soap P204 to diluent is 30%:70%. The number of extraction stages is 8, the number of washing stages is 6, the number of back-extraction stages is 7, and the number of iron removal stages is 2. The washing acid is dilute sulfuric acid (hydrogen ion concentration of 0.05 mol / L), and the back-extraction acid is sulfuric acid (hydrogen ion concentration of 2 mol / L). Manganese-containing back-extraction solution and raffinate are obtained.

[0102] The pH of the raffinate was adjusted to 4.8 by adding liquid alkali. Then, the raffinate was extracted with sodium soap P507 (saponification rate of 25%). The diluent was sulfonated kerosene. The mass ratio of sodium soap P507 to diluent was 30%:70%. The number of extraction stages was 8, the number of washing stages was 5, the number of anti-iron stages was 2, and the number of back-extraction stages was 5. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 4 mol / L). Nickel-lithium raffinate and cobalt-containing solution were obtained.

[0103] Sulfuric acid was added to adjust the pH of the cobalt-containing solution to 4. Then, the cobalt-containing solution was extracted using C272 ammonia soap (saponification rate of 20%). The diluent was sulfonated kerosene. The mass ratio of C272 ammonia soap to diluent was 30%:70%. The extraction stage consisted of 8 stages, the washing stage of 5 stages, the back-extraction stage of 5 stages, and the anti-iron stage of 2 stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A cobalt sulfate solution was obtained. After degreasing, a cobalt salt solution was obtained, which is the purified cobalt sulfate solution.

[0104] The pH of the nickel-lithium raffinate was adjusted to 8 by adding liquid alkali. Then, sodium soap C272 (saponification rate 25%) was used to extract the nickel-lithium raffinate. The diluent was sulfonated kerosene. The mass ratio of sodium soap C272 to diluent was 30%:70%. There were 8 extraction stages, 5 washing stages, 5 back-extraction stages, and 2 anti-iron stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A nickel sulfate solution was obtained. After degreasing, a nickel salt solution was obtained, which was then purified. The lithium-containing raffinate was degreased to obtain a lithium salt solution, which was then sent to the lithium salt workshop.

[0105] Table 2

[0106] element Li Fe P Ni Co Mn Al Cu content(%) 4.51 15.515 8.42 14.87 3.62 6.24 2.43 /

[0107] Example 3

[0108] This embodiment provides an integrated recycling method fully compatible with ternary lithium iron phosphate batteries, the method comprising the following steps:

[0109] (1) After mixing the lithium iron phosphate battery black powder and the ternary electrode battery evenly, a mixed black powder (chemical composition as shown in Table 1) was obtained. The mixed black powder and deionized water were mixed into a slurry at a solid-liquid ratio of 1g:2mL. The slurry was then pumped into an acid leaching reactor with a 20wt% hydrogen peroxide solution. Then, the first sulfuric acid was pumped in for the first acid leaching. The reaction was maintained at 50℃ for 3h. After solid-liquid separation and washing, the first acid leaching solution and the first acid leaching residue were obtained. The second sulfuric acid and sodium thiosulfate were added to the first acid leaching residue for the second acid leaching. The reaction was maintained at 50℃ for 7h. After solid-liquid separation, the second acid leaching solution and graphite residue were obtained.

[0110] Wherein, the concentration of the second sulfuric acid is 1.5 mol / L (referring to hydrogen ion concentration), and the concentration of the first sulfuric acid is 1.5 mol / L (referring to hydrogen ion concentration); the final pH value of the first acid leaching is 2; the amount of the second acid leaching solution or the first sulfuric acid added is 2.5 times the theoretical amount required to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the total amount of hydrogen peroxide added is 1.2 times the theoretical amount required to leach all lithium iron phosphate (calculated based on phosphorus content) and lithium nickel cobalt manganese oxide (calculated based on nickel cobalt manganese content); the mass ratio of the amount of the second sulfuric acid added during the second acid leaching to the mass ratio of the first acid leaching residue is 10 mL: 1 g; the mass of the sodium thiosulfate is 1 times the mass of the first acid leaching residue;

[0111] (2) Add iron powder to the first acid leaching solution in step (1), the molar amount of iron powder added being equal to the Cu in the first acid leaching solution. 2+ The reaction was carried out at 1.4 times the molar amount, and the temperature was maintained at 30℃ for 6 hours. After solid-liquid separation, iron-copper slag and copper-removed liquid were obtained.

[0112] (3) Add 20wt% hydrogen peroxide, crystal-inhibiting dispersant and protective cosolvent to the copper-removed liquid in step (2), then add liquid alkali to adjust the pH to 1, heat to 30℃ and stir for 4h, and after solid-liquid separation, obtain the first phosphorus iron slag and the phosphorus-removed liquid.

[0113] The crystal-inhibiting dispersant is sodium glucose-6-phosphate, and the dispersant is added at a phosphorus content of 25 wt% of the total phosphorus content in the copper-removed solution. The protective co-solvent is sorbitol, and its addition amount is 10 wt% of the amount of the crystal-inhibiting dispersant. The amount of hydrogen peroxide added is theoretically sufficient to remove all Fe... 2+ Oxidized to Fe 3+ 1.3 times;

[0114] (4) Add liquid alkali to the dephosphorized liquid in step (3) to adjust the pH to 5 for iron and aluminum precipitation. Stir at 20°C for 3 hours and let stand for 5 hours. Separate the solid and liquid to obtain iron and aluminum slag and dephosphorized liquid.

[0115] (5) The first phosphorus iron slag in step (3), the iron aluminum slag in step (4) and deionized water are slurried at a solid-liquid ratio of 1g:2mL. Then, liquid alkali is added for alkali dissolution. The alkali dissolution temperature is 80℃ and the time is 2h. The pH of the alkali dissolution endpoint is 14. After solid-liquid separation and washing, the second phosphorus iron slag and aluminum-containing liquid are obtained.

[0116] (6) Add phosphoric acid and sulfuric acid to the second phosphorus iron slag in step (5) for acid dissolution, maintain the temperature at 30°C, dissolve for 7 hours, and the final pH of acid dissolution is 0.2. After solid-liquid separation, phosphorus iron liquid and hydrated phosphorus iron slag are obtained. The phosphorus iron liquid is used for subsequent preparation of anhydrous ferric phosphate, and the hydrated phosphorus iron slag is solid waste.

[0117] The amount of phosphoric acid added is based on a ratio of 1.2:1 between the total molar amount of phosphorus in the second phosphorus-iron slag and the total molar amount of phosphorus in the phosphoric acid, and the molar amount of iron in the second phosphorus-iron slag.

[0118] (7) Add sodium sulfide to the iron and aluminum removal liquid in step (4) to perform deep copper removal, and obtain the pre-extraction liquid and copper slag; the amount of sodium sulfide added is 1.2 times the amount of copper in all the iron and aluminum removal liquid that is theoretically converted into copper sulfide.

[0119] (8) Add sulfuric acid to adjust the pH of the pre-extraction liquid to 3.5. Use sodium soap P204 (saponification rate 40%) to extract the pre-extraction liquid. The diluent is sulfonated kerosene. The mass ratio of sodium soap P204 to diluent is 30%:70%. The number of extraction stages is 8, the number of washing stages is 6, the number of back-extraction stages is 7, and the number of anti-iron stages is 2. The washing acid is dilute sulfuric acid (hydrogen ion concentration is 0.05mol / L), and the back-extraction acid is sulfuric acid (hydrogen ion concentration is 2mol / L). Manganese-containing back-extraction liquid and raffinate are obtained.

[0120] The pH of the raffinate was adjusted to 4.8 by adding liquid alkali. Then, the raffinate was extracted with sodium soap P507 (saponification rate of 25%). The diluent was sulfonated kerosene. The mass ratio of sodium soap P507 to diluent was 30%:70%. The number of extraction stages was 8, the number of washing stages was 5, the number of anti-iron stages was 2, and the number of back-extraction stages was 5. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 4 mol / L). Nickel-lithium raffinate and cobalt-containing solution were obtained.

[0121] Sulfuric acid was added to adjust the pH of the cobalt-containing solution to 4. Then, the cobalt-containing solution was extracted using C272 ammonia soap (saponification rate of 20%). The diluent was sulfonated kerosene. The mass ratio of C272 ammonia soap to diluent was 30%:70%. The extraction stage consisted of 8 stages, the washing stage of 5 stages, the back-extraction stage of 5 stages, and the anti-iron stage of 2 stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A cobalt sulfate solution was obtained. After degreasing, a cobalt salt solution was obtained, which is the purified cobalt sulfate solution.

[0122] The pH of the nickel-lithium raffinate was adjusted to 8 by adding liquid alkali. Then, sodium soap C272 (saponification rate 25%) was used to extract the nickel-lithium raffinate. The diluent was sulfonated kerosene. The mass ratio of sodium soap C272 to diluent was 30%:70%. There were 8 extraction stages, 5 washing stages, 5 back-extraction stages, and 2 anti-iron stages. The washing acid was dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid was sulfuric acid (hydrogen ion concentration of 2 mol / L). A nickel sulfate solution was obtained. After degreasing, a nickel salt solution was obtained, which was then purified. The lithium-containing raffinate was degreased to obtain a lithium salt solution, which was then sent to the lithium salt workshop.

[0123] Example 4

[0124] This embodiment provides an integrated recycling method that is fully compatible with ternary lithium iron phosphate. Except for step (3), in which no protective cosolvent is added, the method is the same as in embodiment 1.

[0125] Comparative Example 1

[0126] This comparative example provides an integrated recycling method that is fully compatible with ternary lithium iron phosphate. Except for step (3), in which no crystal-suppressing dispersant is added, the method is the same as in Example 1.

[0127] The methods described in Examples 3-4 and Comparative Example 1 were performed in the same system as in Example 1.

[0128] In the methods described in the above embodiments and comparative examples, the recovery rates of Ni (Ni content in purified nickel sulfate solution / Ni content in mixed black powder × 100%), Co (Co content in purified cobalt sulfate solution / Co content in mixed black powder × 100%), Li (Li content in lithium salt solution / Li content in mixed black powder × 100%), and slag discharge rate (P content in hydrated iron phosphate slag / P content in mixed black powder × 100%) are shown in Table 3.

[0129] Table 3

[0130]

[0131]

[0132] As can be seen from Table 3 above:

[0133] As can be seen from Examples 1-3 and Comparative Example 1, the present invention, by adding a crystal-inhibiting dispersant to the copper-removed liquid, can promote the phosphonate / PO4 ratio. 3- with Fe 3+ The complex is dispersed in water, reducing the slag yield; as shown in Examples 1-3 and 4, the present invention, by adding a protective co-solvent to the copper removal solution, can stabilize phosphonate / PO4. 3- with Fe 3+ The complex hydration layer acts to inhibit further aggregation and growth of the complex, thereby further reducing the slag discharge rate.

[0134] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A ternary iron-lithium fully compatible integrated recycling method, characterized in that, The integrated recycling method comprises the following steps: (1) mixing and first acid leaching of lithium iron phosphate black powder and ternary material black powder to obtain first acid leaching liquid and first acid leaching residue; (2) one-time copper removal of the first acid leaching liquid in step (1) to obtain copper-removed liquid and copper residue; (3) mixing of the copper-removed liquid in step (2), an oxidizing agent and a crystal growth inhibiting dispersant, and adjusting pH to react to obtain first phosphorus iron residue and phosphorus-removed liquid; The crystal growth inhibiting dispersant comprises an organic phosphonic acid compound; (4) iron and aluminum precipitation of the phosphorus-removed liquid in step (3) to obtain iron and aluminum residue and iron and aluminum-removed liquid; (5) alkali dissolution of the first phosphorus iron residue in step (3) and the iron and aluminum residue in step (4) to obtain second phosphorus iron residue and aluminum-containing liquid, and acid dissolution of the second phosphorus iron residue to obtain phosphorus iron liquid; Secondary copper removal of the iron and aluminum-removed liquid in step (4) to obtain extraction liquid and copper residue, and extraction of the extraction liquid to obtain nickel salt solution, cobalt salt solution and lithium salt solution; When neither the lithium iron phosphate black powder nor the ternary material black powder contains copper, the integrated recycling method does not perform the one-time copper removal in step (2) and the secondary copper removal in step (5).

2. The integrated recycling process of claim 1, wherein, The leaching end point pH of the first acid leaching in step (1) is 0.5-2; Preferably, the temperature of the first acid leaching in step (1) is lower than 60℃; Preferably, the first acid leaching in step (1) is performed by using acid and an oxidizing agent; Preferably, the acid used in the first acid leaching in step (1) is used in an amount of 1.8-2.5 times of the theoretical amount; Preferably, the concentration of the acid used in the first acid leaching in step (1) is 1.5-3.5 mol / L; Preferably, the amount of the oxidizing agent used in the first acid leaching in step (1) is 1.2-1.8 times of the theoretical amount.

3. The integrated recycling process according to claim 1 or 2, characterized in that, The time of the first acid leaching in step (1) is 3-5 h; Preferably, the first acid leaching residue in step (1) is further subjected to a second acid leaching step to obtain graphite residue and second acid leaching liquid, and the second acid leaching liquid is used as acid liquid for the first acid leaching in step (1); Preferably, the second acid leaching is performed by using sulfuric acid and sodium thiosulfate; Preferably, the temperature of the second acid leaching is lower than 60℃, and the time is 7-9 h.

4. The integrated recycling process according to any one of claims 1 to 3, characterized in that, The one-time copper removal in step (2) is performed by using iron powder; Preferably, the amount of the iron powder added is 1.2-1.4 times of the molar amount of copper ions in the first acid leaching liquid; Preferably, the temperature of the one-time copper removal in step (2) is lower than 60℃, and the reaction time is 4-6 h.

5. The integrated recycling process according to any one of claims 1 to 4, characterized in that, When the first acid leaching in step (1) is performed by using acid and an oxidizing agent, the mixing of the copper-removed liquid in step (2), the oxidizing agent and the crystal growth inhibiting dispersant in step (3) further comprises adding a protective cosolute; Preferably, the protective cosolute comprises a saccharide compound and / or a polyhydric alcohol; Preferably, the saccharide compound comprises sucrose and / or trehalose; Preferably, the polyhydric alcohol comprises glycerol and / or sorbitol; Preferably, the amount of the protective cosolute added is 6-10 wt% of the amount of the crystal growth inhibiting dispersant added.

6. The integrated recycling process of any one of claims 1-5, wherein, The crystal inhibitor dispersant is added in an amount of 25wt% to 35wt% of the total phosphorus mass percentage in the copper-removed solution based on the mass percentage of phosphorus in the crystal inhibitor dispersant; Preferably, the organic phosphonic compound in step (3) comprises any one or a combination of at least two of 2-phosphonobutane-1,2,4-tricarboxylic acid, sodium glycerophosphate, sodium glucose-6-phosphate or sodium fructose-6-phosphate; Preferably, the amount of the oxidizing agent added in step (3) is 1.1 times to 1.3 times of the theoretical amount; Preferably, the oxidizing agent in step (3) comprises hydrogen peroxide; Preferably, the pH in step (3) is adjusted to 1 to 3; Preferably, the temperature of the reaction in step (3) is 30°C to 60°C, and the time is 1h to 4h.

7. The integrated cyclic treatment method according to any one of claims 1 to 6, characterized in that, The pH of the phosphorus-removed solution in step (3) is adjusted to 5 to 8 for iron and aluminum precipitation; Preferably, the temperature of the iron and aluminum precipitation in step (4) is 20°C to 40°C, and the reaction time is 1h to 3h; Preferably, the iron and aluminum precipitation in step (4) is allowed to stand for 3h to 5h for solid-liquid separation to obtain iron and aluminum slag and iron and aluminum-removed solution.

8. The integrated cyclic treatment method according to any one of claims 1 to 7, characterized in that, The end point pH of the alkali dissolution in step (5) is 12 to 14; Preferably, the temperature of the alkali dissolution in step (5) is 60°C to 80°C, and the time is 2h to 4h; Preferably, the end point pH of the acid dissolution in step (5) is 0.5 or less; Preferably, the temperature of the acid dissolution in step (5) is 30°C to 50°C, and the time is 5h to 7h.

9. The integrated cyclic treatment method according to any one of claims 1 to 8, characterized in that, The phosphorus-iron solution in step (5) is used to prepare anhydrous iron phosphate; Preferably, sodium sulfide is used for the secondary copper removal in step (5); Preferably, the extractant used in the extraction in step (5) comprises P507 and C272.

10. A system for applying the integrated recycling process according to any one of claims 1 to 9, characterized in that, The system application refers to a system applied in the integrated recycling method, which comprises an acid leaching module, a impurity removal module, a phosphorus-iron slag treatment module and a solvent extraction module; The acid leaching module comprises a mixing pulp preparation unit, a first acid leaching unit and a second acid leaching unit; the mixing pulp preparation unit comprises a black powder storage bin, a screw feeder, a belt conveyor, a mixer and a pulping tank; the first acid leaching unit and the second acid leaching unit each comprise an acid leaching reactor, a metering pump, a filter press and a filtrate storage tank; the first acid leaching unit further comprises a screw conveyor for conveying the filter residue to the second acid leaching unit; the second acid leaching unit further comprises a graphite slag packaging machine; The impurity removal module comprises a copper removal unit, a phosphorus removal unit, an iron and aluminum removal unit and a deep copper removal unit; the copper removal unit comprises a copper removal reactor, an iron powder feeder, a filter press, a copper-removed solution storage tank and an iron and copper slag packaging machine; the phosphorus removal unit comprises a phosphorus removal reactor, a metering pump, a filter press, a phosphorus-removed solution storage tank and a belt conveyor; the iron and aluminum removal unit comprises a iron and aluminum precipitation reactor, a metering pump, a thickener, a filter press, an iron and aluminum-removed solution storage tank and a belt conveyor; the deep copper removal unit comprises a sulfidation reactor, a metering pump, a filter press, a precision filter and an extraction solution storage tank; The phosphorus iron slag treatment module comprises an alkali dissolving unit and an acid dissolving unit; the alkali dissolving unit comprises a feeder, an alkali dissolving reaction kettle, a metering pump, a filter press and an aluminum-containing liquid storage tank; the acid dissolving unit comprises an acid dissolving reaction kettle, a metering pump, a centrifuge and a phosphorus iron liquid storage tank.

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