KR20230081900A - Selective recovery of valuable metal from cathode active material of spent lithium ion batteries - Google Patents

Abstract

The present invention relates to a method for selectively recovering valuable metals from waste cathode active materials, comprising: leaching effective metals from powder of waste cathode active materials under acidic conditions; and recovering the leached effective metal; wherein the step of leaching the effective metal in the powder of the waste cathode active material under the acidic condition; is a step of selectively leaching lithium by additionally introducing an oxidizing agent, obtaining a residue obtained after selective leaching; and selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue.

Description

Method for selectively recovering valuable metal from waste cathode active material {Selective recovery of valuable metal from cathode active material of spent lithium ion batteries}

The present invention relates to a method for selectively recovering valuable metals from waste cathode active materials, and more particularly, waste cathode active material powder containing nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), etc. It relates to a method for easily separating and recovering cobalt, nickel, and manganese included in the residue by selectively leaching and removing lithium (Li) from the residue.

Lithium secondary batteries are key components of electric vehicles and power storage systems (ESS), and their demand is rapidly increasing as the supply of renewable energy without environmental pollution expands. As the demand for electric vehicle batteries increases, the production of cathode active materials for lithium ion batteries (LIBs) based on nickel (Ni)-cobalt (Co)-manganese (Mn) (NCM) is on the rise.

Accordingly, ternary cathode active materials of lithium secondary batteries generated from electric vehicles and energy storage systems (ESSs) whose lifespan has expired contain expensive valuable metals such as lithium (Li), cobalt (Co), and nickel (Ni). And, there is a demand for developing an effective and economical process for recovering these valuable metals and recycling them as raw materials for lithium secondary batteries.

In order to recover valuable metals from conventional waste cathode active materials, lithium ion battery scrap is leached in an acidic solution to recover manganese, cobalt, nickel, and lithium, which are valuable metals, through a stepwise recovery process of manganese recovery-cobalt recovery-nickel recovery-lithium recovery. there is.

However, since the removal of lithium is the final step, the loss rate of lithium is high, and manufacturing costs increase due to the process of recovering each valuable metal with high purity.

In addition, conventional waste cathode active materials are leached by non-selective dissolution, and then impurities are removed-NCM coprecipitation to remove Li-sulfuric acid re-dissolution to recover valuable metals, but since the removal of lithium is the final step, the loss rate of lithium is It is high, and in order to recover the NCM co-precipitation product, additional processes such as sulfuric acid re-dissolution and impurity removal have to be performed, so there has been an uneconomical problem.

In addition, in order to selectively recover only lithium from conventional waste cathode active materials, dry reduction heat treatment is performed at 600 ^° C or higher with hydrogen, activated carbon, Na ₂ CO ₃ , etc., followed by wet water leaching. Dry (reduction heat treatment)-wet (water leaching) ), but it also has problems in that the process is complicated and energy consumption for recovering lithium is high.

Therefore, it is possible to economically and efficiently recover valuable metals such as cobalt and nickel from residues containing cobalt, nickel, and manganese, which is the ternary material from which lithium is removed, by preceding the selective removal or recovery of lithium from the waste cathode active material by a wet process. There is a need for a process that can be performed.

1. Republic of Korea Patent Publication No. 10-2013-0071838 (published on July 1, 2013)

An object of the present invention is to precede the recovery of high-purity lithium from the waste cathode active material, and to recover valuable metals such as cobalt, nickel, and manganese from the residue, and a method for selectively recovering lithium from a ternary waste cathode active material and cobalt (Co) It is to provide a method for recovering valuable metals such as nickel (Ni) and manganese (Mn).

In one embodiment of the present invention, leaching the effective metal in the waste cathode active material powder under acidic conditions; and recovering the leached effective metal; wherein the step of leaching the effective metal in the powder of the waste cathode active material under the acidic condition; is a step of selectively leaching lithium by additionally introducing an oxidizing agent, obtaining a residue obtained after selective leaching; and selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue.

Reduction leaching of the residue to selectively leach cobalt and nickel except for manganese; thereafter, a step of removing impurities from the obtained filtrate may be further included.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the reaction temperature may be 50 to 90 °C.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the leaching pH condition may be 1 or less.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the concentration of the reducing agent may be 0.05 to 0.3M.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the high-liquid ratio condition may be 5 or more.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the reducing agent used is SO ₂ , Na ₂ S ₂ O ₃ , Na ₂ S ₂ O ₅ , NaHSO ₃ , Na ₂ SO ₃ , KHSO ₃ , K ₂ SO ₃ , FeSO ₄ , H ₂ S, glucose, citric acid, malic acid, or a combination thereof.

The oxidizing agent may be one or more selected from the group consisting of KMnO ₄ , Na ₂ S ₂ O ₈ , O ₃ , and NaClO ₃ .

Under the influence of the oxidizing agent, manganese in the waste cathode active material may be precipitated in the form of manganese dioxide, and nickel and cobalt may be precipitated in the form of lithium oxide.

The step of leaching the effective metal in the waste cathode active material powder under the acidic condition; may be a method of leaching at a temperature of 30 to 90 °C.

Leaching the effective metal in the waste cathode active material powder under the acidic condition; may be a method of leaching at a pH of 2 to 7.

Leaching the effective metal in the waste cathode active material powder under the acidic condition; may be a method of leaching for 1 to 4 hours.

The step of leaching the effective metal in the waste cathode active material powder under acidic conditions; may be a method of leaching at a high-liquid ratio of 5 to 10.

Leaching effective metals in the waste cathode active material powder under the acidic conditions; Thereafter, adding a neutralizing agent to the lithium leaching filtrate to precipitate and remove impurities other than lithium; may further include.

The impurity may include a carbonate ((Co-Ni-Mn)CO ₃ ) or a hydroxide ((Co-Ni-Mn)(OH) ₂ ).

The impurities may be recycled in the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue.

A method for selectively recovering lithium from a ternary (nickel (Ni)-cobalt (Co)-manganese (Mn); NCM) waste cathode active material according to the present invention is to selectively recover high-purity lithium through a leaching process of the waste cathode active material. By preceding the steps, high-purity lithium can be obtained with a low lithium loss rate.

In addition, valuable metals such as cobalt, nickel, and manganese can be recovered from the lithium-free residue obtained from the lithium recovery process, economically and efficiently, as well as cobalt (Co), nickel (Ni), Valuable metals such as manganese (Mn) can be recovered.

1 and 2 are schematic flowcharts of a method for separating and recovering valuable metals from waste cathode active material powder according to the present invention.
3 is a view showing the XRD analysis results of the waste cathode active material powder used in the present invention.
4 is a view showing XRD analysis results of the residue after selective leaching of lithium (primary leaching).
5 to 8 are results of leaching rates of valuable metals according to various control variables.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention can selectively recover only high-purity lithium in advance by leaching waste cathode active material powder with an oxidizing agent and then performing a wet process of removing impurities and carbonating the lithium leaching filtrate, and from the lithium-removed residue cobalt, nickel, Valuable metals such as manganese can be recovered, and valuable metals such as high-purity lithium, cobalt, nickel, and manganese can be recovered economically and efficiently. completed the present invention.

The waste cathode active material powder of the present invention is obtained from a cathode active material for a lithium secondary battery that is defective or discarded in the manufacturing process, and in particular, Ni-Co-Mn (NCM) ternary waste cathode active material is used. The collected waste cathode active material is prepared in a powder state through roasting and predetermined powdering processes. In the waste cathode active material powder, various components such as nickel (Ni), cobalt (Co), manganese (Mn), and lithium (Li), as well as trace amounts of aluminum (Al), copper (Cu), iron (Fe), and calcium (Ca) this is mixed.

The method for selectively recovering lithium from waste cathode active material of the present invention is a process of selectively recovering only high-purity lithium by performing a wet process of leaching waste cathode active material powder with an oxidizing agent, removing impurities from the lithium leaching filtrate, and carbonating the filtrate. include

Thereafter, when leaching and impurity removal processes are performed from the residue from which lithium is removed, valuable metals such as cobalt, nickel, and manganese can also be recovered.

Specifically, the present invention comprises the steps of leaching the effective metal in the waste cathode active material powder under acidic conditions; and recovering the leached effective metal, and in the step of leaching the effective metal in the waste cathode active material powder in the acidic condition, a method of selectively leaching lithium by additionally introducing an oxidizing agent.

First, the step of leaching the effective metal in the waste cathode active material powder under the acidic conditions will be described.

In the waste cathode active material powder, the crystal lattice of the layered structure is collapsed or transformed by an oxidizing agent to enable selective dissolution of lithium.

As the oxidizing agent, one or more is selected from the group consisting of KMnO ₄ , Na ₂ S ₂ O ₈ , O ₃ , and NaClO ₃ , but preferably potassium permanganate (KMnO ₄ ) is used to optimize reaction temperature, pH, reaction time and liquid-liquid ratio. It is preferable to carry out the reaction under the conditions of.

The optimum reaction temperature is preferably in the range of 30 to 90 ° C., and at a reaction temperature of 30 ° C or less, the oxidation reaction of manganese is not active, so the leaching rate of valuable metals such as cobalt and nickel increases, resulting in poor selectivity for lithium. The above is not preferable because the cost of energy consumed for evaporation and heating of water increases. More specifically, 50 to 80°C is preferable.

In addition, the optimum pH is preferably in the range of 2 to 10, and when the water leaching pH is 10 or more, the oxidation reaction rate of manganese is slow, and the leaching rate of lithium is low. There are downsides to not having it. Here, the pH may be adjusted by selecting one or more from the group consisting of H ₂ SO ₄ , HCl, and HNO ₃ . A more preferred pH range may be in the range of 2 to 5.

In addition, the optimal reaction time is preferably in the range of 1 to 4 hours, and when it is increased to 4 hours or more, it is not preferable because the leaching rate is not improved compared to the increase in operating time.

In addition, the waste cathode active material powder and the oxidizing agent aqueous solution preferably have a solid-liquid ratio in the range of 5 to 10, and when the solid-liquid ratio L / S is 10 or more, the concentration of lithium in the leachate decreases, increasing the energy cost required to concentrate lithium, If L / S is less than 5, the concentration of lithium increases to 13 g / L or more, and the precipitation reaction of lithium dominates the leaching reaction, so there is a problem that the dissolution rate is remarkably slow.

Leaching effective metals in the waste cathode active material powder under the acidic conditions; Thereafter, a neutralizing agent may be added to the lithium leaching filtrate to precipitate and remove impurities other than lithium.

An alkali neutralizer may be added to remove impurities (Cu, Al, Ca, etc.) other than lithium from the lithium leaching filtrate, and the neutralizer may be NaOH, NH ₄ OH, Na ₂ CO ₃ , K ₂ CO ₃ , CaO, At least one is selected from the group consisting of CaCO ₃ , MgCO ₃ , and MgO, but preferably adjusted to the pH range of 9-10 using sodium carbonate (Na ₂ CO ₃ ).

As described above, after neutralization using a neutralizing agent, the obtained precipitate contains Cu, Al, and Ca as well as cobalt, nickel, manganese, and the like. At this time, the properties of nickel, cobalt, and manganese precipitates vary depending on the type of alkali agent, and are mainly co-precipitated with carbonates ((Co-Ni-Mn)CO ₃ ) or hydroxides ((Co-Ni-Mn)(OH) ₂ ). It can be obtained with water.

The recovering the leached effective metal; may include a lithium recovery step of recovering lithium carbonate by carbonating the lithium leaching filtrate after heating and concentrating it.

The heat-concentration is characterized in that it consists of a temperature of 50 to 95 ^° C, it can be preferably carried out at a temperature of 90 ^° C.

In addition, the carbonation is characterized by adding one or more selected from the group consisting of Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and MgCO ₃ , preferably sodium carbonate (Na ₂ CO ₃ ) relative to 1 mole of lithium. Lithium carbonate can be recovered by adding it at a concentration of 1 to 1.5 moles.

Thereafter, in order to remove sodium co-precipitated in lithium carbonate, high-purity lithium may be recovered by performing water washing twice at a solid-liquid ratio (lithium carbonate and water; L/S) of 3:1.

In addition, the present invention is a lung waste comprising the step of recovering valuable metals such as cobalt (Co), nickel (Ni), manganese (Mn) from the residue separated from the lithium leachate and / or the composition containing the precipitated impurities other than lithium. A method for recovering a ternary valuable metal from a cathode active material is provided.

In the step of recovering valuable metals such as cobalt (Co), nickel (Ni), and manganese (Mn), valuable metals such as leaching reaction and impurity removal reaction may be recovered. Any way possible can be used without any restrictions.

The lithium-free residue obtained by filtering the leachate from the lithium leachate includes MnO ₂ , LiCoO ₂ , and LiNiO ₂ , and the precipitated impurities other than lithium are carbonates ((Co- Ni-Mn)CO ₃ ) or hydroxide ((Co-Ni-Mn)(OH) ₂ ) is characterized in that it includes co-precipitation products.

More specifically, leaching the effective metal in the waste cathode active material powder under acidic conditions; and recovering the leached effective metal; wherein the step of leaching the effective metal in the powder of the waste cathode active material under the acidic condition; is a step of selectively leaching lithium by additionally introducing an oxidizing agent, obtaining a residue obtained after selective leaching; and selectively leaching cobalt and nickel other than manganese by reduction leaching of the residue.

In addition, the residue may be reduced and leached to selectively leach cobalt and nickel except for manganese; thereafter, a step of removing impurities from the obtained filtrate may be further included.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the reaction temperature may be 50 to 90 °C.

If the temperature is less than 50 degrees, there is a problem that the reaction rate is slow and the leaching rate of manganese increases. If the temperature exceeds 90 degrees, there is a problem in that energy cost due to heating increases due to increased evaporation of water rather than improvement in leaching rate. More preferably, it may be 60 to 80 °C.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the leaching pH condition may be 1 or less. When the pH condition is higher than this range, the leaching rate of cobalt and nickel is low. In addition, when the pH range is below the above range, the selectivity of manganese is further improved.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the concentration of the reducing agent may be 0.05 to 0.3M.

In the case of 0.05M or less, there is a problem in that the leaching rate of cobalt and nickel is lowered because the amount of the reducing agent is not sufficient. If it is 0.3M or more, there is a problem in that the selectivity of manganese decreases because the reduction reaction of manganese becomes active.

More preferably, it may be in the range of 0.08 to 0.21M.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the high-liquid ratio condition may be 5 or more.

More preferably, it may be 7 or more or 10 or more. More preferably, it may be 5 to 20, or it may be 10 to 20.

When this high-liquid ratio is satisfied, the leaching rate of valuable metals can be improved.

In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue, the reducing agent used is SO ₂ , Na ₂ S ₂ O ₃ , Na ₂ S ₂ O ₅ , NaHSO ₃ , Na ₂ SO ₃ , KHSO ₃ , K ₂ SO ₃ , FeSO ₄ , H ₂ S, glucose, citric acid, malic acid, or a combination thereof may be included. This is only an example, and most reducing agents showing similar effects can be used.

Therefore, the present invention can selectively leach and recover lithium at a high concentration from the ternary waste cathode active material in a wet process, and recover ternary valuable metals excluding lithium from the leaching residue from which lithium is removed in a simpler and more economical way than conventional processes. That is, nickel, cobalt, manganese, and the like can be recovered.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for explaining the present invention in more detail, and it is to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention. It will be self-evident.

[Example]

[Table 1] shows an example of the raw material composition of the waste NCM cathode active material used in the experiment.

element Co Ni Mn Cu Ca Al Fe Li LOI (%) Content (wt%) 11.22 25.95 9.40 0.40 0.01 0.71 0.43 5.73 4.4

Raw material composition of ternary cathode active material, LOI; Loss on Ignition

[Example 1: Lithium Leaching]

The reaction proposed for leaching lithium in the present invention is as follows.

In the case of potassium permanganate (KMnO ₄ ) added as an oxidizing agent, three electrons are obtained from manganese (trivalent) included in the NCM cathode active material under acidic conditions as shown in the following reaction formula to convert to tetravalent manganese oxide, MnO ₂ , At this time, the layered crystal lattice of the ternary positive electrode active material Li(Ni,Co,Mn)O ₂ is partially collapsed or transformed to create an environment in which lithium can be selectively dissolved.

[reaction formula]

2MnO ₄ ^- + 2H ⁺ + 3Mn ₂ O ₃ -> 8MnO _2(s) + H ₂ O

(consumption of 3 electrons per mol of KMnO ₄ )

( ₄ mol of MnO ₂ generated per 1 mol of KMnO 4 )

At this time, as a side reaction of the reaction, manganese may be partially dissolved as shown in the following side reaction equation.

[side reaction formula]

MnO ₄ ^- + 8H ⁺ + 5e ^- = Mn ²⁺ + 4H ₂ O

The reaction parameters of the following leaching experiment were optimized by changing the reaction temperature, the concentration of the oxidizing agent, and the solid-liquid ratio, and sulfuric acid was used for pH control, and the reaction temperature was 70 ^° C in addition to the effect of the reaction temperature. .

1-1. reaction temperature effect

The leaching behavior of lithium according to the reaction temperature change of the waste NCM cathode active material was investigated. In the leach behavior according to the reaction temperature in Table 2 below (leachate composition, unit: mg/L), when the reaction temperature was 25 ^o C, the concentration of lithium was 4,449 mg/L, showing a leach rate of about 77%, but cobalt, The leaching rates of nickel and manganese also showed a tendency to increase at the same time. As the temperature rose to 70 ^o C, the leaching rates of lithium improved to 86%, and the leaching rates of manganese and cobalt showed a relatively decreasing tendency.

Reaction temperature ( ^o C) Co Ni Mn Cu Ca Al Fe Li 25 2,265 6,696 2,326 ND 3.0 129.2 ND 4,449 70 1,730 6,367 8.8 ND 2.9 111.2 ND 4,782

(Unit: mg/L)

1-2. Oxidizing agent (KMnO ₄ ) added amount

Table 3 below shows lithium leaching behavior (leaching composition, unit: mg/L) according to the amount of oxidizing agent added in an aqueous solution using potassium permanganate (KMnO ₄ ) as an oxidizing agent.

As the amount of added equivalent of the oxidizing agent increased, the leaching rate of lithium improved from 83% at 1 equivalent to 96% at 2 equivalent. On the other hand, when 1 equivalent of the oxidizing agent was added, the leaching rates of cobalt and nickel were leached up to 22% and 44%, respectively, indicating a slight decrease in the selectivity of lithium. At 1.5 equivalent or more, the leaching rates of cobalt and nickel decreased to 9% and 23%, respectively.

Oxidant equivalent Co Ni Mn Cu Ca Al Fe Li One 2,773 10,570 0.8 ND 1.9 129.2 ND 4,532 1.5 1,730 6,367 8.8 ND 2.9 111.2 ND 4,982 2 1,194 6,035 0.5 ND 2.9 147.5 ND 5,490

(Unit: mg/L)

1-3. water leaching pH change

The leaching behavior of lithium (leaching liquid composition, unit: mg/L) according to the change in water leaching pH was investigated. When the cathode active material powder was mixed with water, it showed alkalinity at pH 11 or higher, and sulfuric acid was added to lower the pH to acidity. As shown in Table 4 below, the leaching rate of lithium increased as the water leaching pH decreased, that is, toward the acidic region, and the leaching rate of lithium increased to 96% at pH 2.5.

In general, it is expected that the reaction between the oxidizing agent and manganese in the cathode active material in the acidic and alkaline regions will proceed as follows, and since the oxidizing power tends to increase toward the acidic region, the leaching rate of lithium is improved in the acidic region where the oxidizing power is excellent. It is judged to be

(Acid area) MnO ₄ ^- + 4H ⁺ + 3e ^- = MnO _2(s) + 2H ₂ O, E ^o = 1.70V

(alkaline area) MnO ₄ ^- + 2H ₂ O + 3e ^- = MnO _2(s) + 4OH ^- , E ^o = 0.59V

pH Co Ni Mn Cu Ca Al Fe Li 10.5 4.4 2.5 ND ND ND ND ND 1,505 5.0 ND 1,627 0.18 ND 3.8 ND ND 3,629 2.5 1,194 6,035 0.5 ND 2.9 147.5 ND 5,490

(Unit: mg/L)

1-4. high cost change

The leaching behavior of lithium (leaching liquid composition, unit: mg/L) according to the change in the solid-liquid ratio (waste NCM and aqueous solution) of water leaching was shown. As the solid-liquid ratio decreased from 10 to 5, the leaching rate of lithium decreased from 86% to 83%, the leaching rate of cobalt decreased from 13% to 5%, and the leaching rate of nickel did not change.

High cost (L/S) Co Ni Mn Cu Ca Al Fe Li 10 1,730 6,367 8.8 ND ND 111.2 ND 4,782 5 1,391 16,630 0.5 ND 9.9 192.6 ND 10,850

(Unit: mg/L)

Therefore, when lithium was leached from the waste NCM cathode active material using potassium permanganate (KMnO ₄ ) as an oxidizing agent according to Example 1, the reaction temperature was 70 ° C, 2 equivalents of oxidizing agent, pH 2.5, solid-liquid ratio (L / S) 5 Under the conditions of , the leaching rate of lithium was 96% or more, and the leaching rates of other valuable metals, that is, cobalt, nickel, and manganese were low at 28% or less, confirming that lithium could be recovered selectively. Cobalt, nickel, etc. leached together with lithium could be selectively recovered through the neutralization process (Example 3) below.

[Example 2: Residue Analysis]

The residue separated through vacuum filtration after lithium leaching according to Example 1 was analyzed by XRD (X-ray diffraction).

The results of XRD analysis of the residue recovered after lithium leaching are shown in FIG. 4 . Compared to the raw material composition Li(Ni _x Co _y Mn _z )O ₂ of FIG. 3, in the case of manganese, it can be seen that most of them are converted to manganese dioxide (MnO ₂ ), and in the case of cobalt and nickel, LiCoO ₂ and LiNiO ₂ respectively. It was analyzed to remain in a form bound to lithium.

[Example 3: Impurity Removal]

As in Example 1, in order to remove impurities (Co, Ni, Al, etc.) except for lithium in the lithium leachate, 40 g of Na ₂ CO ₃ was added to a 1L solution of the Li leachate (pH 2.2) to neutralize to a pH in the range of 9 to 10. . After neutralization, 99.9% of lithium was obtained without loss, and the obtained precipitate was a carbonate containing cobalt and nickel contained in the filtrate, which was treated together with the residue separated after lithium leaching as in Example 2 without loss. Valuable metals such as cobalt, nickel, and manganese could be recovered.

division Co Ni Mn Cu Ca Al Fe Li pH leachate 972 5,328 211 0.08 3.1 58.1 ND 5,334 2.2 After neutralization 0.2 ND 0.4 ND 5 ND ND 5,330 9.3

(Unit: mg/L)

[Example 4: Lithium carbonate recovery]

After neutralizing the lithium leaching filtrate as in Example 3, heating and concentrating at a temperature of 90 ^° C, and adding up to 1.5 equivalents of Na ₂ CO ₃ based on the concentration of lithium to recover lithium carbonate. In order to remove co-precipitated sodium in the recovered lithium carbonate, lithium carbonate of 98.4% purity was recovered after washing twice with water at a solid-liquid ratio (lithium carbonate and water; L/S) of 3:1 at 90 ^° C.

division Co Ni Mn Cu Ca Al Fe Na Li Ingredients in Lithium Carbonate
(mg/kg) ND ND 1.7 ND 86 ND ND 8,060 184,800

[Example 5: Cobalt, nickel leaching]

[Table 8] shows the composition of the residue obtained after lithium pre-leaching used in the experiment.

element Co Ni Mn Cu Ca Al Fe Li Content (wt%) 9.96 24.43 11.96 0.003 0.79 0.20 0.03 1.35

* Residue composition

8-1. reaction temperature effect

The leaching behavior of cobalt, nickel, and manganese according to the reaction temperature change during leaching was investigated. The target temperature was set to 25 ° C, 50 ° C, and 70 ° C, and the reaction time was fixed at 3 hours. As a result of the experiment, it was confirmed that the leaching rate of cobalt and nickel increased as the reaction temperature increased, and the leaching rate of manganese decreased.

Based on the reaction temperature of 25℃, each leaching rate is 36% of cobalt, 37% of nickel, and 45% of manganese, and at 50℃, 55% of cobalt, 46% of nickel, and 27% of manganese, and at 70℃, 96% of cobalt and nickel. It was confirmed that 97% and 1.2% manganese. The results are shown in FIG. 5 .

8-2. Effects of pH change

The leaching behavior of cobalt, nickel, and manganese according to pH change during leaching was investigated. Sulfuric acid was used for pH adjustment, and the reaction time was fixed at 3 hours. Based on pH 1.5, the leaching rates of cobalt, nickel, and manganese were 62%, 51%, and 53%, respectively, whereas when adjusted to pH 1 or lower, the leaching rates of cobalt and nickel improved to 96% and 97%, respectively, and manganese leaching The rate showed a decreasing trend to 1.16%. The results are shown in FIG. 6 .

8-3. reducing agent ratio

Any one of SO ₂ , Na ₂ S ₂ O ₃ , Na ₂ S ₂ O ₅ , NaHSO ₃ , Na ₂ SO ₃ , KHSO ₃ , K ₂ SO ₃ , FeSO ₄ , H ₂ S, glucose, citric acid, malic acid of reducing agent was used.

Leaching behavior was investigated at pH 1.5, solid-liquid ratio of 10, reaction temperature of 70 °C, and reaction time of 3 hours by adding reducing agent concentrations of 0.08, 0.13, 0.16, and 0.21 M.

As shown in [Table 9], it was confirmed that the content of cobalt, nickel, and manganese in the filtrate increased as the reducing agent increased. The results are shown as leaching rates in FIG. 7 .

Reducing agent molarity Co (cobalt) Ni (nickel) Mn (manganese) 0.08M 2698 7899 976 0.13M 3596 9395 3862 0.16M 3819 9602 6180 0.21M 4764 10843 8608

* Unit: mg/L

8-4. high cost change

After setting the pH to 1 or less, which reduces manganese leaching, the reaction temperature was fixed at 70 ° C and the reaction time was 3 hours, and after adding 0.16 M of a reducing agent, the leaching behavior of cobalt, nickel, and manganese according to the solid-liquid ratio was investigated.

In the case of the high-liquid ratio of 5, each leaching rate was 84% of cobalt, 81% of nickel, and 0.03% of manganese, and it was confirmed that the leaching rate of 10 was 96% of cobalt, 97% of nickel, and 1.2% of manganese. The results are shown in Figure 8 and [Table 10].

Co Ni Mn Content in residue (wt%) 1.34 2.95 43.1 Concentration in filtrate (mg/L) 4606 12538 68.6

[Example 6: Impurity Removal Process]

Solvent extraction was performed to remove impurities from the filtrate recovered by leaching based on a high-liquid ratio of 10. In order to raise the pH to 3.5, a calcium neutralizing agent having a solid-liquid ratio of 6 was added and proceeded. [Table 11] shows the composition of the filtrate after neutralization.

Co Ni Mn Cu Fe Al Ca Mg pH 4778.1 10146.7 43.2 1.4 29.8 5.8 574.0 96.6 3.5

* Unit: mg/L

As the extraction solvent, a phosphonic acid extractant (trade name DE2PHA) was used, and the organic solvent concentration was 5%, the saponification concentration was 30%, and the extraction stage was 1 stage and the back extraction stage was 1 stage. As shown in [Table 12], it was confirmed that 100% of Fe and Al were extracted, and 76% of Mn and 90% of Ca were extracted.

Co Ni Mn Cu Fe Al Ca Mg Filtrate after extraction 3997.5 9807.51 10.96 1.36 - - 61.15 88.90 Extraction rate (%) 4.6 0.70 75.76 13.92 100 100 89.75 10.96

* Unit: mg/L

The present invention can selectively leach and recover lithium at a high concentration from the ternary waste cathode active material in a wet process, and from the leaching residue from which lithium is removed, ternary valuable metals other than lithium are obtained in a simpler and more economical way than conventional processes, that is, Nickel, cobalt, manganese, etc. can be recovered.

Claims (16)

Leaching effective metals in the waste cathode active material powder under acidic conditions; and
Recovering the leached effective metal; includes,
Leaching the effective metal in the waste cathode active material powder under the acidic condition; is a step of selectively leaching lithium by further adding an oxidizing agent,
obtaining a residue obtained after selective leaching of lithium; and
The method of selectively recovering valuable metals from the waste cathode active material, further comprising: reducing and leaching the residue to selectively leach cobalt and nickel except for manganese.
According to claim 1,
Selectively leaching cobalt and nickel excluding manganese by reducing leaching the residue; Thereafter, removing impurities from the obtained filtrate.
According to claim 1,
In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue;
A method for selectively recovering a valuable metal from a waste cathode active material having a reaction temperature of 50 to 90 ° C.
According to claim 1,
In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue;
A method for selectively recovering valuable metals from waste cathode active material, wherein the leaching pH condition is 1 or less.
According to claim 1,
In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue;
A method for selectively recovering valuable metals from waste cathode active material, wherein the concentration of the reducing agent is 0.05 to 0.3M.
According to claim 1,
In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue;
A method for selectively recovering valuable metals from waste cathode active material, wherein the high-liquid ratio condition is 5 or more.
According to claim 1,
In the step of selectively leaching cobalt and nickel excluding manganese by reduction leaching of the residue;
A method for selectively recovering valuable metals, wherein the reducing agent used includes SO2, Na2S2O3, Na2S2O5, NaHSO3, Na2SO3, KHSO3, K2SO3, FeSO4, H2S, glucose, citric acid, malic acid, or a combination thereof.
According to claim 1,
The oxidizing agent is a method for selectively recovering valuable metals from waste cathode active material, characterized in that at least one selected from the group consisting of KMnO ₄ , Na ₂ S ₂ O ₈ , O ₃ , NaClO ₃ .
According to claim 1,
Manganese in the waste cathode active material is precipitated in the form of manganese dioxide and nickel and cobalt are precipitated in the form of lithium oxide due to the influence of the oxidizing agent.
According to claim 1,
Leaching the effective metal in the waste cathode active material powder in the acidic condition;
A method for selectively recovering valuable metals from waste cathode active material, characterized in that leaching at a temperature of 30 to 90 ° C.
According to claim 1,
Leaching the effective metal in the waste cathode active material powder in the acidic condition;
A method for selectively recovering valuable metals from waste cathode active material, characterized in that leaching at pH 2 to 7.
According to claim 1,
Leaching the effective metal in the waste cathode active material powder in the acidic condition;
A method for selectively recovering valuable metals from waste cathode active material, characterized in that leaching for 1 to 4 hours.
According to claim 1,
Leaching the effective metal in the waste cathode active material powder in the acidic condition;
A method for selectively recovering valuable metals from waste cathode active materials, characterized in that leaching at a high-liquid ratio of 5 to 10.
According to claim 1,
Leaching effective metals in the waste cathode active material powder under the acidic conditions; Since the,
Adding a neutralizing agent to the lithium leaching filtrate to precipitate and remove impurities other than lithium;
According to claim 14,
A method for selectively recovering valuable metals from waste cathode active material, characterized in that the impurities include carbonate ((Co-Ni-Mn)CO ₃ ) or hydroxide ((Co-Ni-Mn)(OH) ₂ ). .
According to claim 15,
The impurity is
Reduction leaching of the residue to selectively leach cobalt and nickel excluding manganese;

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