A method for pretreating black powder from waste lithium batteries

Abstract

The application provides a waste lithium battery black powder pretreatment method, which comprises the following steps: (a) emptying: the waste lithium battery black powder is loaded into a pretreatment reactor and nitrogen or inert gas is introduced to perform emptying; (b) preheating: the waste lithium battery black powder and non-oxidizing carrier gas are preheated respectively; (c) pretreatment: the preheated carrier gas is continuously introduced into the pretreatment reactor to be mixed with the preheated battery black powder and heated to be warmed up, and the battery black powder is kept warm for a certain time t; (d) cooling: the heating device of the pretreatment reactor is closed and the preheated carrier gas is stopped, and then nitrogen or inert gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled; (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50 DEG C, the pretreated battery black powder is obtained by unloading. The method has the advantages of simple and controllable process, high defluorination rate, high efficiency, short process and low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery recycling, in particular to a waste lithium battery black powder pretreatment method. BACKGROUND

[0002] Lithium batteries are widely used in 3C, pure electric vehicles, and electrochemical energy storage due to their high specific energy, long cycle life, and suitable cost. With the large-scale application of lithium batteries, the problem of retired waste lithium battery recycling and reuse has become increasingly important and urgent.

[0003] During the recycling and reuse of waste lithium batteries, a common technical problem is the removal of fluorine from waste lithium batteries. The fluorine contained in waste lithium batteries generally comes from two parts: fluorine-containing electrolyte, such as lithium hexafluorophosphate; and fluorine-containing binder, such as PVDF.

[0004] Currently, fluorine removal from waste lithium batteries is generally achieved by low-temperature volatilization and high-temperature pyrolysis. Low-temperature volatilization takes advantage of the low decomposition temperature of lithium hexafluorophosphate, which decomposes into gaseous phosphorus fluoride and solid LiF at about 150°C. This method can remove more than half of the fluorine in the electrolyte. High-temperature pyrolysis takes advantage of the thermal cracking of PVDF at high temperatures, which produces hydrogen fluoride gas to remove fluorine from the binder. In addition, methods such as alkaline defluorination by water solution soaking and acid roasting defluorination by adding acid are also used.

[0005] The existing waste lithium battery pretreatment defluorination methods have the following problems and deficiencies:

[0006] First, the defluorination rate is low. The existing waste lithium battery pretreatment defluorination method has a low fluorine removal rate, and the residual fluorine content in the pretreated battery black powder can still reach more than 0.3%. The pretreated battery black powder with high residual fluorine content brings a series of separation and purification problems in the subsequent material or element recovery process, as fluorine enters the liquid, gas, and solid phases.

[0007] Second, the fluorine removal efficiency is low. The existing pretreatment defluorination method, such as alkaline defluorination by water solution soaking, requires a long pretreatment defluorination time to achieve the desired defluorination rate, resulting in a relatively low fluorine removal efficiency.

[0008] Third, the cost is high and the economic efficiency is poor. The existing pretreatment defluorination method has a high residual fluorine content in the pretreated battery black powder and a low fluorine removal efficiency. If it is alkaline defluorination by water solution soaking, it also consumes liquid alkali. The residual fluorine in the pretreated battery black powder still needs to be further removed or separated in the subsequent recycling process, which leads to the problem of high cost and poor economic efficiency of the existing pretreatment defluorination method.

[0009] Therefore, it is urgent to develop a high-defluorination rate, high-efficiency, low-cost waste lithium battery black powder pretreatment technology to maximize the recycling value of waste lithium iron phosphate battery. SUMMARY

[0010] In view of the shortcomings of the prior art, the present application aims to provide a waste lithium battery black powder pretreatment method, which is simple and controllable, and aims to defluorinate waste lithium battery black powder, and has the effects of removing organic solvents and binders, and has the advantages of high defluorination rate, high efficiency, short process and low cost.

[0011] The present application is realized by the following scheme:

[0012] A waste lithium battery black powder pretreatment method, comprising the following steps:

[0013] (a) emptying: the waste lithium battery black powder is loaded into a pretreatment reactor, nitrogen or inert gas is introduced into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%; the inert gas is generally one or more of helium and argon;

[0014] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, to obtain the preheated battery black powder; the non-oxidizing carrier gas is preheated in a carrier gas preheater, and the temperature of the preheated carrier gas reaches T_gas, to obtain the preheated carrier gas; wherein T_black and T_gas satisfy: 110℃≤T_black≤200℃, 130℃≤T_gas≤400℃, and T_gas≥T_black;

[0015] (c) pretreatment: the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, and the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, and then the reaction is kept for a certain time t, wherein T_target satisfies: 500℃≤T_target≤850℃;

[0016] (d) cooling: after the reaction time reaches, the heating device of the pretreatment reactor is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor, and then nitrogen or inert gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled;

[0017] (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50℃, the pretreated battery black powder is obtained by unloading.

[0018] The tail gas generated in the whole process is treated by a tail gas treatment device and then discharged and recovered.

[0019] During the heat preservation reaction process of the preheated carrier gas and the preheated battery black powder in the pretreatment reactor, F contained in the waste lithium battery black powder mainly reacts with H cracked in the carrier gas to generate hydrogen fluoride gas with strong volatility, and the hydrogen fluoride gas quickly escapes with the carrier gas, realizing the effect of efficient and deep removal of F from the waste lithium battery black powder, and the chemical reaction formula is as follows:

[0020] F+H=HF↑ (1)

[0021] Further, the non-oxidizing carrier gas is a T_target temperature condition crackable H-containing gas or a mixed gas of a T_target temperature condition crackable H-containing gas and a T_target temperature condition non-active gas, and the partial pressure ratio P_ratio of the non-oxidizing carrier gas satisfies 0.05≤P_ratio≤1.0, P_ratio=P_H / P_Total, P_H is the pressure of the T_target temperature condition crackable H-containing gas, and P_Total is the total pressure of the non-oxidizing carrier gas; the T_target temperature condition crackable H-containing gas is one or more of hydrogen, methane, ethane, water vapor, methanol gas, ethanol gas, formic acid gas, acetic acid gas, methyl carbonate gas, methyl ethyl carbonate gas, ethyl carbonate gas, and dimethyl carbonate gas; and the T_target temperature condition non-active gas is one or more of nitrogen, helium, and argon.

[0022] Further, the heat preservation reaction time t is 5-180 min.

[0023] Further, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas and the waste lithium battery black powder satisfies 120≤GS_ratio≤6000, GS_ratio=V_ 气 / M, V_ 气 is the volume of the non-oxidizing carrier gas, in L; and M is the weight of the waste lithium battery black powder, in Kg. Increasing the gas-solid ratio is beneficial to reducing the partial pressure of hydrogen fluoride gas and increasing the activity of H, thereby facilitating the chemical reaction formula (1) to proceed from left to right, so 120≤GS_ratio; however, increasing the gas-solid ratio greatly increases the amount of non-oxidizing carrier gas consumed, and the power consumption for heating the non-oxidizing carrier gas and maintaining the pretreatment reaction will also greatly increase, which is not conducive to cost reduction, so GS_ratio≤6000.

[0024] Further, the filling rate R of the waste lithium battery black powder in the pretreatment reactor satisfies 5%≤R≤60%, R=M / (ρ×V_ 容 )×100%, wherein ρ is the loose bulk density of the waste lithium battery black powder, in Kg / m3; and V_ 容V is the volume of the pretreatment reactor, in m3; M is the mass of the waste lithium battery black powder, in Kg. If the filling rate R is too small, the waste lithium battery black powder processing capacity per unit time of the pretreatment reactor is small, which is not conducive to providing processing efficiency and reducing processing cost, so the lower limit of the filling rate R is set to 5%. However, if the filling rate R is too large, it is not conducive to the contact and uniform mixing of gas and solid substances, and it is also not conducive to the rapid escape of generated hydrogen fluoride gas, so the upper limit of the filling rate R is set to 60%.

[0025] The waste lithium battery black powder pretreatment method of the present application has the following advantages:

[0026] 1. High defluorination rate: The present application uses a medium-temperature carrier gas roasting method. Through the strengthening of heat transfer and mass transfer, the combination of fluorine elements in the waste lithium battery black powder and H free radicals to generate hydrogen fluoride gas is promoted, and the hydrogen fluoride gas is quickly removed from the solid phase of the waste lithium battery black powder through the carrier gas. The content of residual fluorine in the pretreated battery black powder can be less than 0.05%.

[0027] 2. High efficiency: The present application first preheats the waste lithium battery black powder and the carrier gas, then mixes and heats, and performs pretreatment. By controlling the reaction temperature, reaction time, gas-solid ratio, and filling rate, high-efficiency pretreatment of the waste lithium battery black powder is achieved. On the premise of achieving a high defluorination rate, the fastest pretreatment time only needs about 5 minutes.

[0028] 3. Low cost: The present application directly uses a medium-temperature carrier gas roasting method to achieve high-efficiency deep pretreatment defluorination. The process flow is short, and there is no need for the lengthy treatment processes such as leaching, filtering, and washing required for water solution soaking and alkali defluorination. Also, there is no need to consume expensive chemical reagents, thereby greatly reducing the cost of waste lithium battery black powder pretreatment defluorination. Compared with the existing traditional process, the present application has a significant cost advantage. In addition, the pretreatment defluorination method of the present application does not introduce new inorganic anions and metal cations, which is very beneficial to reducing the difficulty of impurity removal, purification, and separation of the pretreated battery black powder in the subsequent recovery process. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application is a process flow chart of a waste lithium battery black powder pretreatment method. DETAILED DESCRIPTION

[0030] The present application is further described below in conjunction with examples and drawings, but the present application is not limited to the description of the examples.

[0031] Example 1

[0032] A waste lithium battery black powder pretreatment method has a process flow as shown in Figure 1 the drawing, which includes the following steps:

[0033] (a) evacuation: the waste lithium battery black powder with a mass of 100 kg, a bulk density of 0.70 kg / L and a fluorine content of 2.8% is loaded into the pretreatment reactor, i.e. the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 25.5%, and nitrogen gas is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0034] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 110°C, to obtain the preheated battery black powder; and the non-oxidizing carrier gas is preheated in the carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is a mixed gas of methanol gas and nitrogen gas, the partial pressure ratio P_ratio of the non-oxidizing carrier gas is 0.78, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 150°C, to obtain the preheated carrier gas;

[0035] (c) pretreatment: 80000 L of the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, i.e. the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 800 L / kg, and the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, wherein T_target is 650°C, and then the temperature is kept constant for a certain time t, wherein t is 30 min;

[0036] (d) cooling: after the time t reaches, the heating device of the pretreatment reactor is turned off, and the introduction of the preheated carrier gas into the pretreatment reactor is stopped, and then nitrogen gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled;

[0037] (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50°C, the pretreated battery black powder is obtained by unloading.

[0038] The tail gas generated in the whole process is treated by a tail gas treatment device to meet the discharge standard and is recovered.

[0039] Example 2

[0040] A pretreatment method of waste lithium battery black powder, the process flow thereof is as shown in Figure 1 , which comprises the following steps:

[0041] (a) evacuation: the waste lithium battery black powder with a mass of 150 kg, a loose bulk density of 0.85 kg / L and a fluorine content of 3.1% is loaded into the pretreatment reactor, that is, the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 31.5%, and nitrogen gas is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0042] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 150°C, to obtain the preheated battery black powder; and the non-oxidizing carrier gas is preheated in the carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is a mixed gas of methyl ethyl carbonate gas and nitrogen gas, the partial pressure ratio P_ratio of the non-oxidizing carrier gas is 0.62, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 260°C, to obtain the preheated carrier gas;

[0043] (c) pretreatment: 180000 L of the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas and the waste lithium battery black powder is controlled to be 1200 L / kg, and the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, wherein T_target is 800°C, and then the temperature is kept constant for a certain time t, wherein t is 15 min;

[0044] (d) cooling: after the time t reaches, the heating device of the pretreatment reactor is turned off, and the introduction of the preheated carrier gas into the pretreatment reactor is stopped, and then nitrogen gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled;

[0045] (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50°C, the preheated battery black powder is obtained by unloading.

[0046] The tail gas generated in the entire process is treated by a tail gas treatment device to meet the emission standard and is recovered.

[0047] Example 3

[0048] A waste lithium battery black powder pretreatment method, the process flow thereof is as shown in Figure 1 , and includes the following steps:

[0049] (a) evacuation: the waste lithium battery black powder with a mass of 220 kg, a bulk density of 0.67 kg / L and a fluorine content of 3.35% is loaded into the pretreatment reactor, i.e. the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 58.6%, and helium is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0050] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 200°C, to obtain the preheated battery black powder; and the non-oxidizing carrier gas is preheated in the carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is a mixed gas of water vapor and helium, the partial pressure ratio P_ratio of the non-oxidizing carrier gas is 0.89, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 400°C, to obtain the preheated carrier gas;

[0051] (c) pretreatment: 77000 L of the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, i.e. the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 350 L / kg, the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, wherein T_target is 720°C, and then the temperature is kept constant for a certain time t, wherein t is 40 min;

[0052] (d) cooling: after the time t reaches, the heating device of the pretreatment reactor is turned off, and the introduction of the preheated carrier gas into the pretreatment reactor is stopped, and then helium is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled;

[0053] (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50°C, the pretreated battery black powder is obtained by unloading.

[0054] The tail gas generated in the whole process is treated by a tail gas treatment device to meet the discharge standard and is recovered.

[0055] Example 4

[0056] A pretreatment method of waste lithium battery black powder, the process flow thereof is as shown in Figure 1 , and comprises the following steps:

[0057] (a) evacuation: the waste lithium battery black powder with a mass of 25 kg, a bulk density of 0.76 kg / L and a fluorine content of 2.92% is loaded into the pretreatment reactor, i.e. the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 5.9%, and nitrogen gas is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0058] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 180°C, to obtain the preheated battery black powder; and the non-oxidizing carrier gas is preheated in the carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is hydrogen, the partial pressure ratio P_ratio of the non-oxidizing carrier gas is 1.0, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 300°C, to obtain the preheated carrier gas;

[0059] (c) pretreatment: 3750 L of the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, i.e. the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 150 L / kg, the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, wherein T_target is 750°C, and then the temperature is kept constant for a certain time t, wherein t is 5 min;

[0060] (d) cooling: after the time t is reached, the heating device of the pretreatment reactor is turned off, and the introduction of the preheated carrier gas into the pretreatment reactor is stopped, and then nitrogen gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled;

[0061] (e) unloading: when the battery black powder in the pretreatment reactor is cooled to less than 50°C, the pretreated battery black powder is obtained by unloading.

[0062] The tail gas generated in the entire process is treated by a tail gas treatment device to meet the emission standard and is recovered.

[0063] Example 5

[0064] A waste lithium battery black powder pretreatment method, the process flow thereof is as shown in Figure 1 , and includes the following steps:

[0065] (a) evacuation: the waste lithium battery black powder with a mass of 150 kg, a bulk density of 0.72 kg / L and a fluorine content of 3.22% is loaded into the pretreatment reactor, i.e. the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 37.2%, and nitrogen gas is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0066] (b) preheating: the waste lithium battery black powder is preheated in the pretreatment reactor, and the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 130°C, to obtain the preheated battery black powder; and the non-oxidizing carrier gas is preheated in the carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is a mixed gas of ethane and nitrogen, the partial pressure ratio P_ratio of the non-oxidizing carrier gas is 0.15, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 220°C, to obtain the preheated carrier gas;

[0067] (c) pretreatment: 90000 L of the preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, i.e. the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 600 L / kg, and the preheated carrier gas and the preheated battery black powder are heated and warmed up in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, wherein T_target is 500°C, and then the temperature is kept constant for a certain time t, wherein t is 60 min;

[0068] (d) cooling: after the time t of the temperature keeping constant is reached, the heating device of the pretreatment reactor is turned off, and the introduction of the preheated carrier gas into the pretreatment reactor is stopped, and then nitrogen gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0069] (e) unloading: when the battery black powder in the pretreatment reactor is cooled down to less than 50°C, the pretreated battery black powder is obtained by unloading.

[0070] The tail gas generated in the whole process is treated by a tail gas treatment device to meet the discharge standard and is recovered.

[0071] The pretreated battery black powder obtained in each of Examples 1 to 5 is taken for residual fluorine content detection, and the defluorination rate of each example is calculated, and the specific data are shown in Table 1.

[0072] Table 1 residual fluorine content data of the pretreated battery black powder

[0073] residual fluorine content fluorine removal rate Example 1 0.045％ 98.4％ Example 2 0.032％ 99.0％ Example 3 0.048％ 98.6％ Example 4 0.043％ 98.5％ Example 5 0.040％ 98.8％

[0074] As can be seen from the data in Table 1, the residual fluorine content in the pretreated battery black powder obtained in Example 1, Example 2, Example 3, Example 4 and Example 5 is all below 0.05%, which is far lower than the residual fluorine content in the battery black powder obtained by using the prior art defluorination (above 0.3%), and the defluorination rate of each example reaches above 98%.

Claims

1. A method for pretreating black powder from waste lithium batteries, characterized by: The steps include: (a) Emptying: Loading the waste lithium battery black powder into the pretreatment reactor, and introducing nitrogen or inert gas into the pretreatment reactor to empty it until the oxygen content in the pretreatment reactor is less than 0.2%; (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor until the temperature of the preheated waste lithium battery black powder reaches T_black, thereby obtaining preheated battery black powder; preheating the non-oxidizing carrier gas in a carrier gas preheater until the temperature of the preheated carrier gas reaches T_gas, thereby obtaining preheated carrier gas; wherein T_black and T_gas satisfy: 110°C ≤ T_black ≤ 200°C, 130°C ≤ T_gas ≤ 400°C, and T_gas ≥ T_black; the non-oxidizing carrier gas is a H-containing gas that can be cracked under the temperature condition T_target, or a mixed gas of a H-containing gas that can be cracked under the temperature condition T_target and an inactive gas under the temperature condition T_target, and the partial pressure ratio P_ratio of the non-oxidizing carrier gas satisfies 0.05 ≤ P_ratio ≤ 1.0, P_ratio = P_H / P_Total, P_H is the pressure of the H-containing gas that can be cracked under the temperature condition T_target, and P_Total is the total pressure of the non-oxidizing carrier gas; (c) Pretreatment: The preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder. The preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, and then kept warm for a certain time t, wherein T_target satisfies: 500°C ≤ T_target ≤ 850°C; the gas-to-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder satisfies 120 ≤ GS_ratio ≤ 6000, GS_ratio = V_ 气 / M,V_ 气 is the volume of non-oxidizing carrier gas, in L; M is the weight of waste lithium battery black powder, in kg; (d) Cooling: After the holding reaction time is up, the heating device of the pretreatment reactor is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen or an inert gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled; (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

2. The method for pretreating black powder from waste lithium batteries according to claim 1, wherein: The H-containing gas that can be cracked under the T_target temperature condition is one or more of hydrogen, methane, ethane, water vapor, methanol gas, ethanol gas, formic acid gas, acetic acid gas, methyl carbonate gas, ethyl methyl carbonate gas, ethyl carbonate gas, and dimethyl carbonate gas; the inactive gas under the T_target temperature condition is one or more of nitrogen, helium, and argon.

3. The method for pretreating black powder from waste lithium batteries according to claim 1, wherein: The heat preservation reaction time t is 5 to 180 minutes.

4. A method for pretreating black powder from waste lithium batteries according to any one of claims 1 to 3, characterized in that: The filling rate R of the waste lithium battery black powder in the pretreatment reactor satisfies 5%≤R≤60%, R=M / (ρ×V_ 容 )×100%, where ρ is the bulk density of waste lithium battery black powder, in kg / m 3 ; V_ 容 is the volume of the pretreatment reactor, in m 3 ; M is the mass of black powder from used lithium batteries, unit is Kg.

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