METHOD FOR RECOVERY OF VALUABLE METALS FROM SPENT SECONDARY BATTERIES
20240063454 ยท 2024-02-22
Inventors
Cpc classification
B09B3/70
PERFORMING OPERATIONS; TRANSPORTING
H01M6/52
ELECTRICITY
B09B3/40
PERFORMING OPERATIONS; TRANSPORTING
International classification
B09B3/40
PERFORMING OPERATIONS; TRANSPORTING
B09B3/70
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method for recovering valuable metals from a spent secondary battery according to an embodiment of the present disclosure includes a pre-processing process of pre-processing the spent secondary battery, a melting process of heating the pre-processed spent secondary battery to generate a molten solution, and a recovery process of recovering the valuable metals from the molten solution. In the melting process, a chlorinating agent is added, and, in the recovery process, lithium is recovered in a form of lithium dust.
Claims
1. A method for recovering valuable metals from a spent secondary battery, the method comprising: a pre-processing process of pre-processing the spent secondary battery; a melting process of heating the pre-processed spent secondary battery to generate a molten solution; and a recovery process of recovering the valuable metals from the molten solution, wherein, in the melting process, a chlorinating agent is added, and wherein, in the recovery process, lithium is recovered in a form of lithium dust.
2. The method of claim 1, wherein the chlorinating agent includes at least one of CaCl.sub.2, CuCl.sub.2, NaCl, KCl, and CuCl.
3. The method of claim 2, wherein the chlorinating agent includes CaCl.sub.2) or CuCl.sub.2.
4. The method of claim 1, wherein the chlorinating agent is added such that an equivalent of chlorine to lithium present in the pre-processed spent secondary battery is 1.2 or more.
5. The method of claim 1, wherein the pre-processed spent secondary battery is heated to a temperature of 1500 degrees C. or higher in the melting process.
6. The method of claim 1, wherein the lithium dust is LiCl.
7. The method of claim 1, wherein a slag generated in the melting process is CaOSiO.sub.2Al.sub.2O.sub.33-phase slag.
8. The method of claim 7, wherein a composition of the slag is 21-28% CaO, 55-63% SiO.sub.2, and 12-17% Al.sub.2O.sub.3.
9. The method of claim 8, further comprising a spent secondary battery composition analysis process of analyzing a composition of the pre-processed spent secondary battery, and wherein, based on a composition analysis result of the pre-processed spent secondary battery, an input amount of flux is adjusted to achieve the slag composition of 21-28% CaO, 55-63% SiO.sub.2, and 12-17% Al.sub.2O.sub.3.
10. The method of claim 8, wherein a slag composition analysis process is performed to analyze the composition of the slag generated during the melting process, and wherein, based on a composition analysis result of the slag, an additional input amount of flux is adjusted to achieve the slag composition of 21-28% CaO, 55-63% SiO.sub.2, and 12-17% Al.sub.2O.sub.3.
11. The method of claim 1, wherein the pre-processing process includes: a discharge process of discharging the spent secondary battery; a disassembling process of disassembling the spent secondary battery from a pack to a module; a shredding/pulverizing process of shredding and pulverizing the disassembled spent secondary battery; and a drying process of drying the shredded/pulverized spent secondary battery.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
[0021]
DETAILED DESCRIPTION
[0022] Hereinafter, the present disclosure will be described with reference to the drawings.
[0023]
[0024] Referring to
[0025] Pre-Processing Process S100
[0026] A pre-processing process S100 is a process performed before melting spent secondary batteries, and can include a discharge process S10, disassembling process S20, shredding/pulverizing process S30, and drying process S40.
[0027] Discharge Process S10
[0028] The discharge process S10 is a process of discharging power accumulated in the spent secondary batteries to prevent potential explosion of the spent secondary batteries during subsequent processes. The discharge process S10 can be carried out through methods such as discharge using a discharger or saline water discharge using a saline water. For example, through the discharge process S10, the charge rate of the spent secondary batteries can be reduced to 20% or lower.
[0029] Disassembling Process S20
[0030] The disassembling process S20 is a process of disassembling the spent secondary batteries from a pack to the unit of modules or cells. In an embodiment, as illustrated in
[0031] Shredding/Pulverizing Process S30
[0032] The shredding/pulverizing process S30 is a process of shredding and pulverizing the disassembled spent secondary batteries into a shredded material. The shredding/pulverizing process S30 may be carried out under a nitrogen atmosphere while spraying water to prevent sparks and explosions. After the shredding/pulverizing process, the sprayed water and electrolytes that are flowing from the spent secondary batteries may be removed. For example, the water and the electrolytes may be removed using a centrifugal separation method by a rotary barrel.
[0033] Drying Process S40
[0034] The drying process S40 is a process to remove the remaining water and electrolytes after the shredding/pulverizing process S30. For example, the drying process S40 can be carried out by supplying a nitrogen gas heated to approximately 50 degrees C. or higher into a dryer in which the shredded material is placed.
[0035] Composition Analysis Process S150
[0036] In an embodiment of the present disclosure, a composition analysis process S150 may be carried out to analyze the composition of the spent secondary batteries subjected to the pre-processing process S100 (hereinafter referred to as pre-processed spent secondary batteries). The composition analysis result of the pre-processed spent secondary batteries may be used to determine the components and content of a flux to be added in the melting process S200 to be described later. In contrast, in another embodiment of the present disclosure (for example, when the composition of the pre-processed spent secondary batteries is already known), the composition analysis process S150 may be omitted.
[0037] Melting Process S200
[0038] A melting process S200 is a process of heating the pre-processed spent secondary batteries to achieve melting of the pre-processed spent secondary batteries. Specifically, the melting process S200 includes melting the pre-processed spent secondary batteries after mixing them with a flux and a chlorinating agent. This may be performed by heating them at a temperature of 1,500 degrees C. or higher for approximately 3 to 5 hours. During the heating, air, particularly air mixed with oxygen, more preferably oxygen may be added. This allows for the oxidation of by-products such as carbon, aluminum, manganese, and iron present in the pre-processed spent secondary batteries. Carbon can be oxidized and emitted as a carbon dioxide or carbon monoxide gas, while oxides of aluminum, manganese, iron, residual carbon, and others may be incorporated into slag as will be described later. If the heating temperature in the melting process S200 is below than 1,500 degrees C., it may not provide sufficient reactivity, leading to a decrease in the recovery rate of lithium in subsequent processes.
[0039] The flux contains SiO.sub.2 and CaCO.sub.3, resulting in the formation of CaOSiO.sub.2Al.sub.2O.sub.3 3-phase slag along with an oxidation product of aluminum (Al.sub.2O.sub.3) present in the spent secondary batteries. In addition, the slag may contain byproducts present in the pre-processed spent secondary batteries such as manganese, iron, carbon, as well as a portion of nickel, cobalt, copper, and lithium.
[0040] The composition of the 3-phase slag generated in the melting process S200 is desirably 2128% CaO, 5563% SiO.sub.2, and 1217% Al.sub.2O.sub.3, and the input amount of the flux (the components and content of the input flux) is adjusted to achieve the above composition of the slag. In this case, the melting point of the slag is approximately 1,200 degrees C. (see
[0041] Furthermore, a process can be carried out to analyze the composition of the slag generated during the melting process S200. In this case, based on the composition analysis result of the generated slag, the input amount of the flux during the melting process S200 may be adjusted to achieve a desirable composition of 2128% CaO, 5563% SiO.sub.2, and 1217% Al.sub.2O.sub.3 of the 3-phase slag. Specifically, the input amount of SiO.sub.2 and CaCO.sub.3 to be additionally added may be adjusted to achieve the composition of 21-28% CaO, 55-63% SiO.sub.2, and 1217% Al.sub.2O.sub.3 of the 3-phase slag, based on the composition of the slag.
[0042] The chlorinating agent can include at least one of CaCl.sub.2), CuCl.sub.2, NaCl, KCl, and CuCl, and can be added such that the equivalent of chlorine to lithium present in the pre-processed spent secondary batteries may be 1.2 or more. If the equivalent of the chlorinating agent is less than 1.2, a chlorination reaction of lithium cannot proceed sufficiently, resulting in a lower lithium recovery rate in subsequent processes.
[0043] During the melting process S200, nickel, cobalt, and copper present in the pre-processed spent secondary batteries are reduced from oxides. The relevant reaction is represented by the following Equation (1).
MO+C=CO+M (M=Ni,Co,Cu)Eq. (1)
[0044] The reduced nickel, cobalt, and copper exist in the form of a molten solution and, due to the difference in specific gravity from the slag, exist separately under the slag.
[0045] During the melting process S200, lithium present in the pre-processed spent secondary batteries undergoes a chlorination reaction with the chlorinating agent, resulting in the formation of a lithium chloride (LiCl). The relevant reaction is represented by the following Equation (2), Equation (3), and Equation (4).
Li.sub.2O+SiO.sub.2+MCl.sub.2=2LiCl+MSiO.sub.3 (M=Ca,Cu)Eq. (2)
Li.sub.2O+2SiO.sub.2+Al.sub.2O.sub.3+MCl.sub.2=2LiCl+MAl.sub.2Si.sub.2O.sub.8 (M=Ca,Cu)Eq. (3)
Li.sub.2O+6SiO.sub.2+Al.sub.2O.sub.3+2MCl=2LiCl+2MAlSi.sub.3O.sub.8 (M=Na,K,Cu)Eq. (4)
[0046] Specifically, if CaCl.sub.2) or CuCl.sub.2 is used as the chlorinating agent, a lithium chloride can be generated through Equation (2) and Equation (3), and if NaCl, KCl, or CuCl is used as the chlorinating agent, a lithium chloride can be generated through Equation (4).
[0047] Recovery Process S300
[0048] A recovery process S300 is a process of recovering nickel, cobalt, copper, and the lithium chloride (LiCl).
[0049] The molten solution of nickel, cobalt, and copper generated by reduction in the melting process S200 has a higher specific gravity than the slag, allowing it to exist separately under the slag. This property can be utilized to separate and recover nickel, cobalt, and copper from the slag.
[0050] The boiling point of the lithium chloride (LiCl) generated in the melting process S200 is approximately 1,382 degrees C., which means that it can vaporize and form a dust-like substance during the melting process S200. The dust-like lithium chloride (LiCl) can be collected and recovered through a dust collector such as an electrostatic precipitator or a bag filter.
[0051] Hereinafter, the present disclosure will be described in detail through examples and a comparative example. In the examples, the above-described processes were utilized to recover valuable metals, namely nickel, cobalt, copper, and lithium, from the spent secondary batteries, and the recovery rate of these metals were measured. On the other hand, in the comparative example, the melting process S200 was performed without the addition of the chlorinating agent, and the recovery rates of valuable metals, namely nickel, cobalt, copper, and lithium, were measured. The recovery rates of nickel, cobalt, copper, and lithium were calculated by subtracting the amount discharged as the slag from the input amount. The composition of the shredded spent secondary batteries powder (pre-processed spent secondary batteries) used in the examples and the comparative example is presented in Table 1 below.
TABLE-US-00001 TABLE 1 Component Ni Co Cu Li Mn Al Fe C Content 17.0 5.7 9.2 3.3 5.7 10.2 0.1 28.8 (%)
Comparative Example
[0052] In Comparative Example, 100 g of shredded spent secondary batteries powder was mixed with a flux composed of 82.2 g of SiO.sub.2 and 57.0 g of CaCO.sub.3 without the addition of a chlorinating agent, and then a melting process was performed with injection of oxygen at 1,500 degrees C. for 3 hours.
Examples 1-5
[0053] In Examples 1 to 5, the recovery rates of valuable metals were investigated based on the temperature in the melting process S200.
[0054] Specifically, 100 g of shredded spent secondary batteries powder was mixed with a flux composed of 82.2 g of SiO.sub.2 and 21.3 g of CaCO.sub.3, and 39.6 g of CaCl.sub.2) as a chlorinating agent (with the equivalent of chlorine to lithium: 1.5) and then a melting process was performed with injection of oxygen for 3 hours. The melting temperature was set at 1300 degrees C. for Example 1, 1350 degrees C. for Example 2, 1400 degrees C. for Example 3, 1450 degrees C. for Example 4, and 1500 degrees C. for Example 5.
[0055] The experimental conditions and recovery rates of valuable metals in Examples 1 to 5 and Comparative Example are presented in Table 2.
TABLE-US-00002 TABLE 2 Example Example Example Example Example Comparative 1 2 3 4 5 Example Input Shredded 100.0 100.0 100.0 100.0 100.0 100.0 Amount Spent (g) Secondary Batteries SiO.sub.2 82.2 82.2 82.2 82.2 82.2 82.2 CaCO.sub.3 21.3 21.3 21.3 21.3 21.3 57.0 CaCl.sub.2 39.6 39.6 39.6 39.6 39.6 (Equivalent (Equivalent (Equivalent (Equivalent (Equivalent of 1.5) of 1.5) of 1.5) of 1.5) of 1.5) Melting Temperature 1,300 1,350 1,400 1,450 1,500 1,500 Process (degrees C.) Conditions Reaction 3 3 3 3 3 3 Time (hr) Recovery Ni 97.7 97.9 98.2 98.7 99.2 99.2 Rate Co 97.3 97.8 97.9 98.5 98.6 98.4 (%) Cu 86.7 95.3 97.5 98.0 98.7 98.5 Li 47.4 54.5 60.6 78.3 91.5 0.2
[0056] As can be seen in Table 2, in Examples 1 to 5, lithium was successfully recovered without the need for additional processes for slag. Further, in Examples 1 to 5, higher temperatures in the melting process resulted in higher recovery rates of valuable metals, especially lithium. Particularly in Example 5 which had a temperature of 1500 degrees C. in the melting process, a high lithium recovery rate of 91.5% was achieved.
[0057] On the other hand, in Comparative Example where no chlorinating agent was added during the melting process, most of lithium was discharged as slag, making it impossible to recover lithium without additional processes for slag.
Examples 6-10
[0058] In Examples 6 to 10, the recovery rates of valuable metals were investigated based on the equivalent of the chlorinating agent.
[0059] Specifically, 100 g of shredded spent secondary batteries powder was mixed with a flux composed of SiO.sub.2 and CaCO.sub.3, and CaCl.sub.2) as a chlorinating agent, and then a melting process was performed with injection of oxygen at 1500 degrees C. for 3 hours. The input amount of CaCl.sub.2) was 26.4 g in Example 6 (the equivalent of chlorine to lithium: 1.0), 31.7 g in Example 7 (the equivalent of chlorine to lithium: 1.2), 39.6 g in Example 8 (the equivalent of chlorine to lithium: 1.5), 47.5 g in Example 9 (the equivalent of chlorine to lithium: 1.8), and 52.8 g in Example 10 (the equivalent of chlorine to lithium: 2.0).
[0060] In all of Examples 6 to 10, SiO.sub.2 was added in the amount of 82.2 g. As for CaCO.sub.3, it was adjusted in the amount according to the input amount of CaCl.sub.2) (chlorinating agent) and was added in the amount of 33.2 g in Example 6, 28.4 g in Example 7, 21.3 g in Example 8, 14.2 g in Example 9, and 9.4 g in Example 10.
[0061] The experimental conditions and recovery rates of valuable metals in each Example are presented in Table 3.
TABLE-US-00003 TABLE 3 Example Example Example Example Example 6 7 8 9 10 Input Shredded 100.0 100.0 100.0 100.0 100.0 Amount Spent (g) Secondary Batteries SiO.sub.2 82.2 82.2 82.2 82.2 82.2 CaCO.sub.3 33.2 28.4 21.3 14.2 9.4 CaCl.sub.2 26.4 31.7 39.6 47.5 52.8 (Equivalent (Equivalent (Equivalent (Equivalent (Equivalent of 1.0) of 1.2) of 1.5) of 1.8) of 2.0) Melting Temperature 1,500 1,500 1,500 1,500 1,500 Process (degrees C.) Conditions Reaction 3 3 3 3 3 Time (hr) Recovery Ni 98.9 99.1 99.2 99.1 99.2 Rate Co 98.8 98.5 98.6 98.7 98.4 (%) Cu 98.5 98.7 98.7 98.5 98.7 Li 67.1 90.3 91.5 91.4 91.7
[0062] As can be seen in Table 3, it was possible to recover lithium without any additional processes for slag in Examples 6 to 10. Furthermore, a higher input amount of CaCl.sub.2) (chlorinating agent) resulted in a higher lithium recovery rate. In particular, in Examples 2 to 5 where the input amount of CaCl.sub.2) exceeded 31.7 g (the equivalent of chlorine to lithium: 1.2) or more, a high lithium recovery rate of 90% or more was achieved.
Example 5, 11-14
[0063] In Examples 5 and 11 to 14, the recovery rates of valuable metals were investigated based on the type of the chlorinating agent.
[0064] Specifically, 100 g of shredded spent secondary batteries powder was mixed with a flux composed of SiO.sub.2 and CaCO.sub.3, and a chlorinating agent such that the equivalent of chlorine to lithium is 1.5, and then a melting process was performed with injection of oxygen at 1500 degrees C. for 3 hours. In Example 5, CaCl.sub.2 was mixed in the amount of 39.6 g. In Example 11, CuCl.sub.2 was mixed in the amount of 47.9 g. In Example 12, NaCl was mixed in the amount of 41.7 g. In Example 13, KCl was mixed in the amount of 53.2 g. In Example 14, CuCl was mixed in the amount of 70.6 g.
[0065] In all of Examples 5 and 11 to 14, SiO.sub.2 was added in the amount of 82.2 g, and CaCO.sub.3 was adjusted in the amount according to the input amount of the chlorinating agent. In Example 5, 21.3 g of CaCO.sub.3 was added, and in Examples 11 to 14, 57.0 g of CaCO.sub.3 was added.
[0066] The experimental conditions and recovery rates of valuable metals in each Example are presented in Table 4.
TABLE-US-00004 TABLE 4 Example Example Example Example Example 5 11 12 13 14 Input Shredded 100.0 100.0 100.0 100.0 100.0 Amount Spent (g) Secondary Batteries SiO.sub.2 82.2 82.2 82.2 82.2 82.2 CaCO.sub.3 21.3 57.0 57.0 57.0 57.0 Chlorinating CaCl.sub.2 CuCl.sub.2 NaCl KCl CuCl agent 39.6 g 47.9 g 41.7 g 53.2 g 70.6 g (Equivalent (Equivalent (Equivalent (Equivalent (Equivalent of 1.5) of 1.5) of 1.5) of 1.5) of 1.5) Melting Temperature 1,500 1,500 1,500 1,500 1,500 Process (degrees C) Conditions Reaction 3 3 3 3 3 Time (hr) Recovery Ni 99.2 98.9 98.6 98.1 98.2 Rate Co 98.6 98.6 98.1 98.0 97.6 (%) Cu 98.7 98.2 98.3 97.7 97.3 Li 91.5 89.2 72.4 54.3 73.6
[0067] As can be seen in Table 4, it was possible to recover lithium without any additional processes for slag in Examples 5 and 11 to 14. Furthermore, the type of the chlorinating agent affected the lithium recovery rate. In particular, in Examples 5 and 11 where CaCl.sub.2) and CuCl.sub.2 were added, higher lithium recovery rates were exhibited.