CN116632395A - A recovery method for valuable metals in waste batteries - Google Patents

Abstract

The invention provides a method for recovering valuable metals in waste batteries. The recovery method includes the following steps: using waste battery materials as positive electrodes, negative electrode active materials as negative electrodes, and metal salt solutions as electrolytes for electrolytically extracting lithium to obtain rich Lithium solution and slag after lithium extraction, the lithium-rich solution is subjected to lithium precipitation to complete the recovery of lithium ions; the slag after lithium extraction is roasted and leached to obtain a valuable metal ion enrichment solution to complete the recovery of valuable metals The recovery method of valuable metals in the waste battery of the present invention, the recovery method adopts the electric field assisted lithium extraction-reduction roasting coupling method, successfully realizes the direct separation of elements such as lithium and nickel, cobalt and manganese, thereby being able to prepare battery-grade carbonic acid Lithium, and can make nickel, cobalt, and manganese enter the solution in the form of ions. Therefore, the overall recovery process is short, the process is simple, the cost is low, no extraction agent is needed, and the loss rate of valuable metals is low.

Description

A recovery method for valuable metals in waste batteries

technical field

The invention belongs to the technical field of battery recycling, and relates to a method for recycling valuable metals in waste batteries.

Background technique

Lithium-ion batteries are widely used as an important means of energy storage for new energy vehicles, but due to the limited life of lithium-ion batteries, a large number of lithium-ion batteries will inevitably be scrapped over time. Waste lithium-ion batteries are obtained after pretreatment processes such as crushing and sorting. The waste contains rare and precious metal elements such as lithium, nickel, and cobalt. Economic and social benefits.

At present, in the existing technology, the mainstream way to deal with the electrode active materials of waste lithium-ion batteries is: 1) acid reduction leaching to obtain ions containing Li ⁺ , Ni ²⁺ , Co ²⁺ , Mn ²⁺ , Al ³⁺ , Fe ³⁺ The leaching solution is precipitated to remove iron and aluminum, and then the pH value is adjusted to obtain a single metal precipitate; 2) after the precipitation removes iron and aluminum, nickel, cobalt, manganese are extracted and back-extracted to obtain a salt solution containing only nickel or cobalt or manganese; as disclosed in CN 107994288A A method for recovering valuable metals from waste nickel-cobalt-lithium-manganese-oxide ternary battery cathode materials, including: (1) dismantling and grinding the nickel-cobalt-lithium-manganese-oxide ternary battery cathode materials and carbon powder After mixing evenly, perform roasting and reduction; (2) place the roasted material in a stirring device, add pure water, add dilute acid dropwise, adjust the pH and soak and perform filtration treatment; (3) take the filtrate obtained after filtration, and the The filtrate is adjusted to pH with sodium hydroxide, and after filtering to remove impurities, soluble carbonate is added to precipitate lithium carbonate, and the precipitated lithium carbonate is filtered and washed to realize the recovery of lithium metal elements; however, acidic leaching is followed by removal of impurities Recycling nickel, cobalt, manganese and other metals to finally recycle lithium will lead to a low recovery rate of lithium, and only a single type of waste lithium-ion battery will be processed.

For example, CN 112646974A discloses a method for reclaiming valuable metals from waste ternary lithium battery cathode materials. The method first roasts the pretreated waste ternary cathode powder, and then immerses in water and selectively extracts lithium. Prioritize the recovery of lithium salt; then obtain nickel-cobalt-manganese sulfate solution through acid leaching, impurity removal, and extraction, and use it as a raw material to directly prepare a ternary precursor; although it can reduce the impact of lithium on subsequent nickel-cobalt by extracting lithium first. The impact of manganese extraction can improve the recovery rate of lithium, but the overall process flow is long and still involves complex extraction process.

Based on the above studies, it is necessary to provide a recovery method for valuable metals in waste batteries. The recovery method has a short process flow, simple process, high universality, low loss rate of valuable metals, and can be recycled to obtain battery-grade raw materials.

Contents of the invention

The purpose of the present invention is to provide a recovery method for valuable metals in waste batteries. The recovery method adopts the electric field assisted lithium extraction-reduction roasting coupling method, and successfully realizes the direct separation of lithium and nickel, cobalt, manganese and other elements, thereby being able to prepare Battery-grade lithium carbonate can make nickel, cobalt and manganese enter the solution in the form of ions. Therefore, the overall recovery process is short, the process is simple, the cost is low, no extraction agent is needed, and the loss rate of valuable metals is low.

To achieve this purpose of the invention, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a method for recovering valuable metals in waste batteries, said recovery method comprising the steps of:

(1) The waste battery material is used as the positive electrode, the negative electrode active material is used as the negative electrode, and the metal salt solution is used as the electrolyte to carry out electrolytic extraction of lithium to obtain a lithium-rich solution and a slag after lithium extraction. Recycle;

(2) Roasting and leaching the slag after lithium extraction described in step (1) to obtain a valuable metal ion enrichment solution, and complete the recovery of the valuable metal.

The present invention adopts the electric field-assisted lithium extraction-reduction roasting coupling method to recover valuable metals, wherein the electric field-assisted lithium extraction is performed first and then roasted, the lithium ions can be extracted first, and then other ions can be recovered, avoiding the need for recovery of other valuable metals. Lithium ion recovery rate reduction problem, while the electrolytic lithium extraction of the present invention can selectively leach lithium ions, not only the recovery rate of lithium ions is high but also the recovery purity is high; the subsequent reduction roasting can further promote the leaching of other valuable elements, reducing It overcomes the limitation of subsequent leaching process conditions, enables other valuable metals to be leached under mild conditions, and improves the leaching rate of other valuable metals.

Preferably, the metal salt solution in step (1) includes sodium salt and/or potassium salt.

Preferably, the metal salt solution in step (1) includes ammoniacal metal salt solution and/or acidic metal salt solution, preferably ammoniacal metal salt solution, more preferably ammoniacal sodium salt solution.

The electrolyte used in the electrolysis of the present invention includes metal salts, and the electrolyte is an acidic system or an ammoniacal system, wherein the presence of metal ions can improve the conductivity of the solution and promote the transmission of ions, and the acidic system and ammoniacal system can promote The leaching of metals improves the leaching rate and realizes simultaneous lithium extraction and selective leaching.

Preferably, the ammoniacal sodium salt solution includes NH ₃ ·H ₂ O, Na ₂ SO ₄ and Na ₂ SO ₃ .

The electrolyte system of the present invention adopts the NH ₃ ·H ₂ O-Na ₂ SO ₄ -Na ₂ SO ₃ system, which has better compatibility with electric field-assisted lithium extraction.

Preferably, the concentration of NH ₃ ·H ₂ O is 0.1-2 mol/L, such as 0.1 mol/L, 0.5 mol/L, 1 mol/L, 1.5 mol/L or 2 mol/L, but not limited to Listed values, other unlisted values within the range of values also apply.

Preferably, the concentration of Na ₂ SO ₄ is 10-50g/L, such as 10g/L, 30g/L or 50g/L, but not limited to the listed values, other unlisted values within the range of values are the same Be applicable.

Preferably, the concentration of Na ₂ SO ₃ is 1-30g/L, such as 1g/L, 5g/L, 10g/L, 15g/L, 20g/L, 25g/L or 30g/L, but Not limited to the numerical values listed, other unlisted numerical values within the numerical range are also applicable.

Preferably, after the lithium-enriched solution in step (1) is subjected to lithium precipitation, a lithium-containing compound and a regenerated metal salt are obtained, and the regenerated metal salt is reused in the electrolytic lithium extraction step.

The lithium-rich solution obtained by electrolytic lithium extraction in the present invention can obtain regenerated metal salts after lithium precipitation, and the regenerated metal salts can be reused in the electrolyte solution for electrolytic lithium extraction, realizing the recycling of materials, and the use of regenerated metal salts is unnecessary. Can affect the recovery effect of the present invention.

Preferably, the lithium precipitation method described in step (2) includes: adding sodium carbonate solution to the lithium-rich solution to obtain lithium carbonate.

Preferably, the current density of electrolytic lithium extraction in step (1) is 50-200A/m ² , such as 50A/m ² , 100A/m ² , 150A/m ² or 200A/m ² , but not limited to Listed values, other unlisted values within the range of values also apply.

The current density of the electrolytic extraction of lithium in the present invention affects the selective leaching of ions. Electrolytic extraction of lithium under the current density of the present invention can improve the leaching rate of lithium and the purity of lithium. If the current density is too low or too high, The leaching of lithium ions will be incomplete, or the leaching of other ions will affect the purity of lithium ion recovery.

Preferably, the temperature of electrolytic lithium extraction in step (1) is 30-60°C, such as 30°C, 40°C, 50°C or 60°C, and the time is 1-5h, such as 1h, 2h, 3h, 4h or 5h, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the waste battery material in step (1) is mixed with a binder and a solvent, and then pressed into a block to be used as a positive electrode.

Preferably, the pressing pressure is 1-5MPa, such as 1MPa, 2MPa, 3MPa, 4MPa or 5MPa, and the time is 0.5-3h, such as 0.5h, 1.5h or 3h, but not limited to the listed values , other unlisted values within the value range are also applicable.

Preferably, based on the mass of the positive electrode being 100wt%, the amount of the binder is 0.1-1wt%, such as 0.1wt%, 0.5wt% or 1wt%, but not limited to the listed values, the values Other unrecited values within the range also apply.

Preferably, based on the mass of the positive electrode being 100wt%, the amount of the solvent used is 10-30wt%, such as 10wt%, 20wt% or 30wt%, but not limited to the enumerated values, other values within the range are not The listed values also apply.

Preferably, the binder includes but not limited to PVDF, and the solvent includes but not limited to NMP.

Preferably, the negative electrode active material in step (1) includes any one of bulk graphite, aluminum plate or stainless steel.

Preferably, the waste battery materials in step (1) include positive electrode active materials.

Preferably, the waste battery material in step (1) further includes any one or a combination of at least two of negative electrode active materials, conductive agents, binders, positive electrode current collectors and negative electrode current collectors.

The waste battery materials described in step (1) of the present invention include positive electrode active materials, negative electrode active materials, conductive agents, binders, positive electrode current collectors, and negative electrode current collectors; , can also include negative electrode active materials, conductive agents, binders, positive electrode current collectors and negative electrode current collectors at the same time. The other substances included will not affect the recovery of the battery. When the above substances are included at the same time, the recovered substances can also obtain higher yields. Therefore, the method of the present invention does not need to finely sieve battery materials to prepare positive electrode active materials, which greatly improves the convenience of battery recycling.

Preferably, the waste battery material in step (1) is the mixed powder after crushing the cells of waste batteries.

Preferably, in the waste battery material described in step (1), the content of the positive electrode active material is not less than 10%, such as 10wt%, 30wt%, 50wt%, 70wt% or 90wt%, but not limited to the listed values , other unlisted values within the numerical range are also applicable, preferably 45-95%, more preferably 45-85%.

Preferably, the waste battery material in step (1) is obtained by short-circuit discharge, disassembly, crushing and screening of waste batteries.

The waste batteries in the present invention include any one or a combination of at least two of waste _LiCoO2 batteries, _LiNiO2 batteries, nickel-cobalt-manganese lithium-ion batteries, nickel-cobalt-aluminum lithium-ion batteries or nickel-cobalt-manganese-aluminum lithium-ion batteries.

Preferably, additives are added during the roasting process in step (2).

Preferably, the additive is a solid compound.

Preferably, the additives include acidic substances and/or sulfur-containing compounds.

The present invention also adds acidic substances or sulfur-containing compounds as additives during the roasting process. The addition of additives can promote subsequent ion leaching, enabling leaching to achieve normal temperature water leaching, which not only improves the leaching rate of valuable metals, but also enables subsequent ion leaching. The leaching process can be carried out under relatively mild conditions; at the same time, the additive of the present invention is a solid compound. Compared with liquid substances, the solid additive is easier to mix evenly with the slag after lithium extraction, and the roasting reduction effect is better. Sulfur compounds can also achieve better recovery results, making the overall recovery method more gentle.

Preferably, the additive includes any one or a combination of at least two of citric acid, oxalic acid, sodium bisulfite, sodium sulfide, ammonium sulfate, iron sulfate or aluminum sulfate.

Preferably, the mass ratio of the additive to the slag after lithium extraction is (0.5-5):1, for example, it can be 0.5:1, 1.5:1, 2.5:1, 3.5:1, 4.5:1 or 5:1, But not limited to the listed values, other unlisted values within the range of values are also applicable.

The mass ratio of the additive in the present invention to the slag after lithium extraction is within the above preferred range, which can further ensure the recovery effect. If the amount of the additive added is relatively too small, the leaching rate of the metal will be low. If the amount of the additive added is relatively large , it will cause additional loss of additives and also affect the recovery effect.

Preferably, ball milling is performed before the additive is roasted with the slag after lithium extraction.

Preferably, the rotational speed of the ball mill is 100-500rpm, such as 100rpm, 200rpm, 300rpm, 400rpm or 500rpm, and the time is 0.5-3h, such as 0.5h, 1.5h, 2.5h or 3h, but not limited to Listed values, other unlisted values within the range of values also apply.

Preferably, the roasting temperature in step (2) is 300-700°C, such as 300°C, 400°C, 500°C, 600°C or 700°C, and the time is 0.5-5h, such as 0.5h, 1h, 2h, 3h, 4h or 5h, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the leaching method in step (2) includes water immersion.

Preferably, the leaching temperature in step (2) is 10-30°C, for example, 10°C, 20°C or 30°C, but not limited to the listed values, other unlisted values within the range of values are also applicable, and the time It is 0.5-2h, for example, it can be 0.5h, 1h, 1.5h or 2h, but it is not limited to the listed values, and other unlisted values within the range of values are also applicable.

In the present invention, after electric field assisted lithium extraction and reducing acid roasting, the roasted material obtained can be immersed in water under mild conditions to obtain valuable metal ions.

Preferably, the solid-to-liquid ratio of the leaching in step (2) is 20-200g/L, for example, it can be 20g/L, 100g/L or 200g/L, but it is not limited to the listed values, and other values are not listed within the range values are also applicable.

As a preferred technical solution of the present invention, the recovery method comprises the steps of:

(1) Mix the waste battery material with a binder and a solvent, and press the mixed material under a pressure of 1-5MPa for 0.5-3h to form a block, then use it as the positive electrode, and use the negative electrode active material as the negative electrode, ammoniacal sodium salt solution As an electrolyte, electrolytically extract lithium at a current density of 50-200A/ ^m2 for 1-5 hours to obtain a lithium-rich solution and a slag after lithium extraction. The lithium-rich solution is subjected to lithium precipitation to complete the recovery of lithium ions;

The ammoniacal sodium salt solution includes NH ₃ ·H ₂ O, Na ₂ SO ₄ and Na ₂ SO ₃ , the concentration of NH ₃ ·H ₂ O is 0.1-2mol/L, and the concentration of Na ₂ SO ₄ is 10 -50g/L, the concentration of Na ₂ SO ₃ is 1-30g/L;

(2) With the mass ratio of (0.5-5): 1, the additive and the slag after lithium extraction described in step (1) are ball milled for 0.5-3h at a speed of 100-500rpm, and then at a temperature of 300-700°C Carry out roasting for 0.5-5h, and the obtained roasted material is immersed in water at a solid-to-liquid ratio of 20-200g/L for 0.5-2h at 10-30°C to obtain a valuable metal ion enrichment solution, and complete the recovery of valuable metals;

The additive is a solid compound, including any one or a combination of at least two of citric acid, oxalic acid, sodium bisulfite, sodium sulfide, ammonium sulfate, iron sulfate or aluminum sulfate.

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

The invention adopts electric field-assisted lithium extraction-reducing acid roasting coupling, first extracts lithium ions, and then recovers other ions, successfully realizes the direct separation of lithium and nickel, cobalt, manganese and other elements in battery waste, avoiding the recovery of other valuable metals from making lithium The problem of reduced ion recovery rate not only prepares battery-grade lithium salt, but also metals such as nickel, cobalt, and manganese enter the solution in the form of ions, and the method of the present invention has strong applicability to raw materials, simple process, and good process repeatability. The loss rate of valuable metals is low, the cost is low, and large-scale industrial production is possible.

Description of drawings

Fig. 1 is the flowchart of recovery method described in embodiment 1 of the present invention;

Fig. 2 is the XRD figure of lithium carbonate described in embodiment 1 of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below through specific embodiments. It should be clear to those skilled in the art that the examples are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

This embodiment provides a recovery method for valuable metals in waste batteries, the flow chart of the recovery method is shown in Figure 1, including the following steps:

(1) Soak the waste nickel-cobalt lithium manganese oxide battery in 5% NaCl saline solution until the end-of-discharge voltage is 1V, disassemble the battery cell, and then carry out mechanical crushing as a whole, and then sieve out the particle size less than 0.1mm waste battery materials;

The waste battery material is mixed with PVDF and NMP, and the mixed material is pressed under a pressure of 3 MPa for 1 h to form a block of 8 × 5 × 1 cm. As the positive electrode, block graphite with the same size as the positive electrode is used as the negative electrode. The neutral sodium salt solution is used as the electrolyte, an electric field is applied, and at a current density of 100A/ ^m2 , lithium is electrolytically extracted at a temperature of 60°C for 2 hours, and the electric field-assisted lithium extraction is completed to obtain a lithium-containing solution and a slag after lithium extraction. Add sodium carbonate solution in lithium-containing solution, carry out sinking lithium, obtain lithium carbonate, complete the recovery of lithium ion, the XRD pattern of described lithium carbonate is as shown in Figure 2;

The ammoniacal sodium salt solution includes NH ₃ ·H ₂ O, Na ₂ SO ₄ and Na ₂ SO ₃ , the concentration of NH ₃ ·H ₂ O is 2mol/L, and the concentration of Na ₂ SO ₄ is 50g/L , the concentration _{of Na2SO3} is 20g/L;

Based on the mass of the positive electrode as 100wt%, the amount of PVDF is 1wt%, and the amount of NMP is 19wt%;

The waste battery material includes positive electrode active material, negative electrode active material, conductive agent, binder, positive electrode current collector and negative electrode current collector;

(2) With a mass ratio of 3:1, the additive and the slag after extracting lithium described in step (1) are ball milled for 1 hour at a speed of 300 rpm, and then roasted for 1 hour at a temperature of 500° C. ℃, with 100g/L solid-liquid ratio water immersion for 1h, to obtain nickel ion, cobalt ion and manganese ion enrichment solution, complete the recovery of valuable metals; the nickel ion, cobalt ion and manganese ion enrichment solution after After impurity purification, the impurity ions are removed, and then after extraction or precipitation, nickel-cobalt-manganese products are obtained;

The additive is oxalic acid.

Example 2

This embodiment provides a recovery method for valuable metals in waste batteries, the recovery method comprising the following steps:

(1) Soak the waste nickel-cobalt lithium manganese oxide battery in 5% NaCl saline solution until the end-of-discharge voltage is 1V, disassemble the battery cell, and then carry out mechanical crushing as a whole, and then sieve out the particle size less than 0.1mm waste battery materials;

The waste battery material was mixed with PVDF and NMP, and the mixed material was pressed under a pressure of 1 MPa for 3 hours into a block of 8 × 5 × 1 cm. As the positive electrode, block graphite with the same size as the positive electrode was used as the negative electrode. The neutral sodium salt solution is used as the electrolyte, an electric field is applied, and at a current density of 200A/ ^m2 , lithium is extracted by electrolysis at a temperature of 30°C for 5 hours to complete the electric field-assisted lithium extraction to obtain a lithium-containing solution and a slag after lithium extraction. Add sodium carbonate solution to the lithium-containing solution, carry out lithium precipitation, obtain lithium carbonate, and complete the recovery of lithium ions;

The ammoniacal sodium salt solution includes NH ₃ ·H ₂ O, Na ₂ SO ₄ and Na ₂ SO ₃ , the concentration of the NH ₃ ·H ₂ O is 0.1mol/L, and the concentration of Na ₂ SO ₄ is 10g/L L, the concentration _{of Na2SO3} is 1g/L;

Based on the mass of the positive electrode as 100wt%, the amount of PVDF is 0.1wt%, and the amount of NMP is 10wt%;

The waste battery material includes positive electrode active material, negative electrode active material, conductive agent, binder, positive electrode current collector and negative electrode current collector;

(2) With the mass ratio of 0.5:1, the additive and the slag after extracting lithium described in step (1) are ball milled for 3 hours at a speed of 100 rpm, and then roasted for 0.5 hours at a temperature of 700° C., and the obtained roasted material is At 10°C, immerse in water at a solid-to-liquid ratio of 20g/L for 2 hours to obtain a nickel ion, cobalt ion and manganese ion enrichment solution to complete the recovery of valuable metals;

The additive is citric acid.

Example 3

This embodiment provides a recovery method for valuable metals in waste batteries, the recovery method comprising the following steps:

(1) Soak the waste nickel-cobalt lithium manganese oxide battery in 5% NaCl saline solution until the end-of-discharge voltage is 1V, disassemble the battery cell, and then carry out mechanical crushing as a whole, and then sieve out the particle size less than 0.1mm waste battery materials;

The waste battery material is mixed with PVDF and NMP, and the mixed material is pressed under a pressure of 5 MPa for 0.5h into a block of 8×5×1 cm, and then used as a positive electrode, and a block graphite of the same size as the positive electrode is used as a negative electrode, The ammoniacal sodium salt solution is used as the electrolyte, and an electric field is applied, and at a current density of 50A/ ^m2 , the electrolytic extraction of lithium is carried out at a temperature of 60°C for 1 hour, and the electric field-assisted lithium extraction is completed to obtain a lithium-containing solution and a slag after lithium extraction. Add sodium carbonate solution in the lithium-containing solution, carry out lithium sinking, obtain lithium carbonate, complete the recovery of lithium ion;

The ammoniacal sodium salt solution includes NH ₃ ·H ₂ O, Na ₂ SO ₄ and Na ₂ SO ₃ , the concentration of NH ₃ ·H ₂ O is 1mol/L, and the concentration of Na ₂ SO ₄ is 50g/L , the concentration _{of Na2SO3} is 30g/L;

Based on the mass of the positive electrode as 100wt%, the amount of PVDF is 1wt%, and the amount of NMP is 30wt%;

The waste battery material includes positive electrode active material, negative electrode active material, conductive agent, binder, positive electrode current collector and negative electrode current collector;

(2) With the mass ratio of 5:1, the additive and the slag after extracting lithium described in step (1) are ball milled for 0.5h at a speed of 500rpm, and then roasted for 5h at a temperature of 300°C. The obtained roasted material is At 30°C, immerse in water at a solid-to-liquid ratio of 200g/L for 0.5h to obtain nickel ion, cobalt ion and manganese ion enrichment solutions, and complete the recovery of valuable metals;

The additive is oxalic acid.

Example 4

This embodiment provides a recovery method for valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the sodium chloride solution is used as the electrolyte in step (1); The concentration of sodium ion in the sodium ion concentration is identical with the concentration of sodium ion in the ammoniacal sodium salt solution described in embodiment 1.

Example 5

This embodiment provides a method for recovering valuable metals in waste batteries, except that the recovery method uses 2mol/L sulfuric acid to replace the NH ₃ ·H ₂ O in the electrolyte described in step (1), and the rest are the same as Example 1 is the same.

Example 6

This embodiment provides a method for recovering valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the current density in step (1) is 20A/m ² .

Example 7

This embodiment provides a method for recovering valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the current density in step (1) is 300 A/m ² .

Example 8

This embodiment provides a method for recovering valuable metals in waste batteries. The recovery method is the same as in Example 1 except that no additives are added in step (2).

Example 9

This embodiment provides a method for recovering valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the additive in step (2) is sodium sulfide.

Example 10

This embodiment provides a recovery method for valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the additive in step (2) is 98% industrial sulfuric acid.

Example 11

This embodiment provides a recovery method for valuable metals in waste batteries, the recovery method is the same as in Example 1 except that the mass ratio of the additive in step (2) to the slag after lithium extraction is 0.1:1 .

Example 12

This embodiment provides a method for recovering valuable metals in waste batteries. The recovery method is the same as in Example 1 except that the mass ratio of the additive in step (2) to the slag after lithium extraction is 8:1. .

Comparative example 1

This comparative example provides a recovery method for valuable metals in waste batteries, except that the waste battery materials are first roasted in step (2) and then electrolytically extracted in step (1), the recovery method is the same as Example 1 is the same.

The purity of lithium carbonate of above embodiment and comparative example and the leaching rate of major element are measured by atomic absorption spectrometer, test result is as shown in table 1:

Table 1

It can be seen from Table 1:

(1) The recovery method provided by the present invention successfully realizes the direct separation of lithium and nickel-cobalt-manganese ions, thereby battery-grade lithium carbonate can be prepared; as can be seen from Example 1 and Comparative Example 1, Comparative Example 1 cannot reach the technical effect of the present invention , after roasting and water immersion first, then electrolysis will reduce the effect of selective lithium extraction and reduce the purity of recovered lithium. The present invention first conducts electric field-assisted selective extraction of lithium, and then performs reductive roasting, which can increase the concentration of valuable ions The leaching rate can be improved, and the problem that the recovery of other valuable metals will reduce the recovery rate of lithium ions can be avoided; it can be seen from Example 1 and Examples 4-5 that when the electrolyte of the present invention uses ammoniacal sodium salt, the recovery effect can be further improved.

(2) It can be known from Example 1 and Examples 6-7 that the current density of electrolytic lithium extraction will affect the selective lithium extraction effect; it can be seen from Example 1 and Example 8 that the additive of the present invention can promote the leaching of other metal ions rate; From Example 1 and Examples 9-10, it can be seen that when the additive of the present invention adopts sulfide, it can also obtain a better recovery effect, and can make the overall recovery process more gentle. In addition, when using a solid compound, it can be promoted. The mixing uniformity of the slag after lithium extraction improves the recovery effect; it can be seen from Example 1 and Examples 11-12 that the amount of additives added will also affect the recovery effect of the present invention.

In summary, the present invention provides a method for recovering valuable metals in waste batteries. The recovery method adopts an electric field-assisted lithium extraction-reduction roasting coupling method, and successfully realizes the direct separation of lithium from elements such as nickel, cobalt, and manganese, thereby enabling The battery-grade lithium carbonate is prepared, and nickel, cobalt, and manganese can enter the solution in the form of ions. Therefore, the overall recovery process is short, the process is simple, the cost is low, no extraction agent is needed, and the loss rate of valuable metals is low.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any person skilled in the art is within the technical scope disclosed in the present invention. Easily conceivable changes or substitutions all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. The method for recycling valuable metals in waste batteries is characterized by comprising the following steps of:

(1) Taking waste battery materials as a positive electrode, taking a negative electrode active material as a negative electrode, taking a metal salt solution as an electrolyte to carry out electrolysis and lithium extraction, so as to obtain a lithium-rich solution and lithium-extracted slag, and carrying out lithium precipitation on the lithium-rich solution to complete the recovery of lithium ions;

(2) Roasting and leaching the slag after the lithium extraction in the step (1) to obtain valuable metal ion enrichment liquid, and recycling valuable metals.

2. The recovery method according to claim 1, wherein the metal salt solution of step (1) comprises sodium salt and/or potassium salt;

preferably, the metal salt solution in step (1) comprises an ammoniacal metal salt solution and/or an acidic metal salt solution, preferably an ammoniacal metal salt solution, further preferably an ammoniacal sodium salt solution;

preferably, the ammoniacal sodium salt solution includes NH ₃ ·H ₂ O、Na ₂ SO ₄ And Na (Na) ₂ SO ₃ ；

Preferably, the NH ₃ ·H ₂ The concentration of O is 0.1-2mol/L, na ₂ SO ₄ The concentration of (A) is 10-50g/L, na ₂ SO ₃ The concentration of (2) is 1-30g/L.

3. The recovery method according to claim 1 or 2, wherein after the lithium-rich solution in step (1) is subjected to lithium precipitation, a lithium-containing compound and a regenerated metal salt are obtained, and the regenerated metal salt is reused in the electrolytic lithium extraction step;

preferably, the current density of the electrolytic lithium extraction in the step (1) is 50-200A/m ² ；

Preferably, the temperature of the electrolytic lithium extraction in the step (1) is 30-60 ℃ and the time is 1-5h.

4. The recycling method according to any one of claims 1 to 3, wherein the waste battery material of step (1) is mixed with a binder and a solvent, and then pressed into a block for use as a positive electrode;

preferably, the pressing pressure is 1-5MPa, and the time is 0.5-3h;

preferably, the binder is used in an amount of 0.1 to 1wt% based on 100wt% of the positive electrode;

preferably, the solvent is used in an amount of 10 to 30wt% based on 100wt% of the positive electrode.

5. The recycling method according to any one of claims 1 to 4, wherein the anode active material of step (1) comprises any one of bulk graphite, aluminum plate, or stainless steel;

preferably, the waste battery material in the step (1) comprises a positive electrode active material;

preferably, the waste battery material in the step (1) further comprises any one or a combination of at least two of a negative electrode active material, a conductive agent, a binder, a positive electrode current collector and a negative electrode current collector.

6. The recycling method according to any one of claims 1 to 5, wherein the waste battery material in the step (1) is a mixed powder obtained by crushing the cells of the waste battery;

preferably, the waste battery material in the step (1) is obtained through short-circuit discharge, disassembly, crushing and screening of the waste battery.

7. The recovery method according to any one of claims 1 to 6, wherein an additive is further added during the firing in step (2);

preferably, the additive is a solid compound;

preferably, the additive comprises an acidic substance and/or a sulfur-containing compound;

preferably, the additive comprises any one or a combination of at least two of citric acid, oxalic acid, sodium bisulphite, sodium sulphide, ammonium sulphate, iron sulphate or aluminium sulphate.

8. The recovery method according to claim 7, wherein the mass ratio of the additive to the slag after lithium extraction is (0.5-5): 1;

preferably, before roasting the additive and the slag after lithium extraction, ball milling is performed first;

preferably, the rotation speed of the ball mill is 100-500rpm, and the time is 0.5-3h.

9. The recovery method according to any one of claims 1 to 8, wherein the roasting temperature in step (2) is 300 to 700 ℃ for 0.5 to 5 hours;

preferably, the leaching in step (2) comprises water leaching;

preferably, the leaching in the step (2) is carried out at a temperature of 10-30 ℃ for 0.5-2h;

preferably, the solid to liquid ratio of the leaching in step (2) is 20-200g/L.

10. The recovery method according to any one of claims 1 to 9, characterized in that the recovery method comprises the steps of:

(1) Mixing waste battery materials with a binder and a solvent, pressing the mixture obtained by mixing for 0.5-3h under the pressure of 1-5MPa to form a block body, taking the block body as a positive electrode, taking a negative electrode active material as a negative electrode, taking an ammoniacal sodium salt solution as an electrolyte, and carrying out the process of mixing at 50-200A/m ² Carrying out electrolysis and lithium extraction for 1-5h under the current density to obtain lithium-rich liquid and slag after lithium extraction, wherein the lithium-rich liquid is subjected to lithium precipitation to complete the recovery of lithium ions;

the ammoniacal sodium salt solution comprises NH ₃ ·H ₂ O、Na ₂ SO ₄ And Na (Na) ₂ SO ₃ The NH is ₃ ·H ₂ The concentration of O is 0.1-2mol/L, na ₂ SO ₄ The concentration of (A) is 10-50g/L, na ₂ SO ₃ The concentration of (2) is 1-30g/L;

(2) 1, mixing the additive with the slag obtained after the lithium extraction in the step (1) in a mass ratio of (0.5-5), ball milling for 0.5-3h at a rotating speed of 100-500rpm, roasting for 0.5-5h at a temperature of 300-700 ℃, and soaking the obtained roasted material in water for 0.5-2h at a solid-liquid ratio of 20-200g/L at a temperature of 10-30 ℃ to obtain valuable metal ion enrichment liquid, thereby completing the recovery of valuable metals;

the additive is a solid compound comprising any one or a combination of at least two of citric acid, oxalic acid, sodium bisulphite, sodium sulfide, ammonium sulfate, ferric sulfate or aluminum sulfate.