Novel method for preferentially extracting lithium from ternary mixed powder through catalytic reduction of water gas

Abstract

The invention provides a novel method for preferentially extracting lithium by catalytically reducing ternary mixed powder through water gas, and relates to the field of waste ternary lithium battery recovery methods, and the novel method comprises the following steps: step 1, discharging, disassembling, crushing and screening waste ternary lithium batteries; step 2, putting the powder into a calcining furnace, and introducing water gas; 3, roasting for a period of time at a certain temperature in a water gas atmosphere; step 4, after roasting, transferring the material to a reaction kettle after the material is cooled, adding a certain amount of deionized water, stirring, and controlling the reaction temperature and the reaction time; step 5, filtering and washing the reaction product to obtain filtrate containing valuable metal lithium ions; and step 6, evaporating and concentrating the filtrate to a certain concentration, adjusting the pH value, adding sodium carbonate for precipitating lithium carbonate, and after high-temperature reaction, filtering, washing and drying to obtain the battery-grade lithium carbonate. The method can solve the problems of long process for recovering lithium metal from waste ternary lithium batteries and low recovery rate.

Description

Technical Field

[0001] The invention belongs to the field of waste ternary lithium battery recycling methods, and specifically relates to a new method for preferentially extracting lithium from ternary mixed powder by catalytic reduction of water-gas. Background Art

[0002] The use of various ternary lithium batteries has increased. The service life of ternary lithium batteries is limited. After a certain period of time, the performance of various aspects will decrease, resulting in a large number of discarded ternary lithium batteries. Discarded ternary lithium batteries contain a variety of harmful metals and dangerous compounds. If they are not properly recycled and handled, they will cause serious environmental pollution and even endanger human health. However, discarded lithium batteries are rich in valuable metals such as lithium, nickel, cobalt, and manganese, which have recyclable and usable value. Therefore, in order to reduce the pollution hazards of discarded lithium-ion batteries and increase economic benefits, the development of efficient and low-cost waste lithium-ion battery recycling technology is an inevitable trend in scientific and technological development.

[0003] Due to the high value of lithium metal, the priority recovery of lithium from discarded ternary lithium batteries has become the main goal. However, the traditional recovery process is relatively long, including leaching, impurity removal, extraction, evaporation and crystallization, which leads to a large loss of lithium metal and a low recovery rate. Therefore, the priority extraction of lithium from discarded ternary lithium batteries is an important research topic faced by the field of lithium battery recycling. At present, the types of lithium-ion batteries carried by new energy vehicles are diverse, and the disassembly and crushing process will inevitably cause the mixing of different types of positive electrode materials, thereby greatly increasing the difficulty of priority lithium extraction. The existing process for the priority extraction of lithium from discarded lithium-ion batteries can no longer meet the priority extraction of lithium in the case of mixed lithium batteries of different types, and it is necessary to find a simple and efficient new method for the priority extraction of lithium. Based on this, the present invention is proposed to solve the above-mentioned problems. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention proposes a new method for preferentially extracting lithium from ternary mixed powder by water gas catalytic reduction. Water gas is mainly used as a reducing agent. After roasting, the high-valent metals of nickel, cobalt and manganese are reduced to low-valent elements or oxides. After water immersion, the separation of metallic lithium is achieved, the recovery rate of metallic lithium is improved, and the technical key to preferentially extracting lithium from discarded ternary batteries is achieved.

[0005] The technical solution adopted by the embodiment of the present application to solve the technical problem is:

[0006] A new method for preferentially extracting lithium from ternary mixed powder by water-gas catalytic reduction comprises the following steps:

[0007] Step 1: discharging, disassembling, crushing and screening the discarded ternary lithium batteries;

[0008] Step 2, placing the powder in a calcining furnace and introducing water gas;

[0009] Step 3, roasting at a certain temperature for a period of time under a water gas atmosphere;

[0010] Step 4: After calcination, the material is cooled and then moved to a reactor, a certain amount of deionized water is added and stirred, and the reaction temperature and reaction time are controlled;

[0011] Step 5, filtering and washing the reaction product to obtain a filtrate containing valuable metal lithium ions, wherein the contents of lithium, nickel, cobalt, manganese, and aluminum in the filtrate are 2.5-3 g / L, 0.5-1 mg / L, 1-3 mg / L, 5-8 mg / L, and 0.03-0.5 mg / L, respectively;

[0012] Step 6: Evaporate and concentrate the filtrate to a certain concentration, adjust the pH, add sodium carbonate to precipitate lithium carbonate, and after high-temperature reaction, filter, wash, and dry to obtain battery-grade lithium carbonate.

[0013] According to some embodiments of the present application, in step 1, powders with a mesh size below 200 are sieved and selected.

[0014] According to some embodiments of the present application, in step 2, at normal pressure, according to the flow rate of 2m 3 / h-4m 3 / h water gas is introduced and used as reducing agent.

[0015] According to some embodiments of the present application, in the step 3, the calcination temperature is 550-700°C.

[0016] According to some embodiments of the present application, in the step 3, the calcination time is 1.5-3h.

[0017] According to some embodiments of the present application, in step 4, the solid content is 15%-30%, the reaction temperature is 40-60° C., and the reaction time is 0.5-1 h.

[0018] According to some embodiments of the present application, in step 6, the lithium concentration of the concentrated solution is 15-30 g / L, the pH of the lithium-containing solution is 9-11; the sodium carbonate concentration is 220-250 g / L, and a reverse addition method is adopted, that is, the lithium-containing solution is added with the sodium carbonate solution.

[0019] According to some embodiments of the present application, in step 6, the temperature of precipitating lithium carbonate is 90-95° C., the adding time is 50-80 min, and the reaction time is 30-60 min.

[0020] According to some embodiments of the present application, in step 6, the precipitated lithium carbonate is washed twice, the drying temperature is 100-140° C., and the drying time is 1-2 h.

[0021] The advantages of the embodiments of the present application are:

[0022] The present invention can solve the problem of long process and low recovery rate of lithium metal recovery from discarded ternary lithium batteries. It is mainly reflected in:

[0023] (1) Using water gas as a reducing agent, high-valent nickel, cobalt and manganese are reduced to low-valent elements or oxides, and the separation of metallic lithium is achieved by leaching.

[0024] (2) The main components of water gas are carbon monoxide and hydrogen. Compared with the reduction gas using hydrogen alone, it has better explosion resistance and higher safety.

[0025] (3) It can achieve the effect of preferentially extracting lithium from discarded batteries and increase the recovery rate of lithium metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A flow chart of a new method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powders provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0029] In order to make the purpose, technical solutions and advantages of the implementation methods of this application clearer, the technical solutions in the implementation methods of this application will be clearly and completely described below in conjunction with the drawings in the implementation methods of this application. Obviously, the described implementation methods are part of the implementation methods of this application, not all of the implementation methods. Based on the implementation methods in this application, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] Embodiment 1:

[0031] like Figure 1 As shown, a new method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powders comprises the following steps:

[0032] (1) Discharging, disassembling, crushing and screening the discarded ternary batteries, and selecting powder below 200 mesh;

[0033] (2) Place 50 kg of powder in a calcining furnace at 2 m 3 / h water gas is introduced as a reducing agent;

[0034] (3) Calcination at 600°C for 1.5 h in a water gas atmosphere.

[0035] (4) After calcination, the material is cooled and then transferred to a reactor. A certain amount of deionized water (solid content 15%) is added and stirred. The mixture is leached at a reaction temperature of 50°C for 1 hour.

[0036] (5) The reaction product is filtered and washed to obtain a filtrate containing lithium ions. The recovery rate of Li in the filtrate is measured by ICP-MS and is 96.73%.

[0037] (6) The filtrate was evaporated and concentrated to a lithium content of 17 g / L. The concentrated solution was added to a 250 g / L sodium carbonate solution and reacted at 95° C. for 60 min. The filtered product was washed twice (deionized water at 100° C.) and dried at 90° C. for 2 h to obtain battery-grade lithium carbonate. The results are shown in the following table.

[0038] Embodiment 2:

[0039] like Figure 1 As shown, a new method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powders comprises the following steps:

[0040] (1) Discharging, disassembling, crushing and screening the discarded ternary batteries, and selecting powder below 200 mesh;

[0041] (2) Place 50 kg of powder in a calcining furnace and heat at 3 m 3 / h water gas is introduced as a reducing agent;

[0042] (3) Calcination at 600°C for 3 h in a water gas atmosphere;

[0043] (4) After calcination, the material is cooled and then transferred to a reactor. A certain amount of deionized water (solid content 20%) is added and stirred. The mixture is leached at a reaction temperature of 50°C for 1 hour.

[0044] (5) The reaction product is filtered and washed to obtain a filtrate containing lithium ions. The recovery rate of Li in the filtrate is measured by ICP-MS and is 98.06%.

[0045] (6) The filtrate was evaporated and concentrated to a lithium content of 17 g / L. The concentrated solution was added to a 250 g / L sodium carbonate solution and reacted at 95° C. for 60 min. The filtered product was washed twice (deionized water at 100° C.) and dried at 90° C. for 2 h to obtain battery-grade lithium carbonate. The results are shown in the following table.

[0046]

[0047] The present invention can solve the problem of long process and low recovery rate of lithium metal recovery from discarded ternary lithium batteries. It is mainly reflected in: (1) using water gas as a reducing agent to reduce high-valent nickel, cobalt and manganese to low-valent elements or oxides, and leaching to achieve the separation of metallic lithium. (2) The main components of water gas are carbon monoxide and hydrogen, which has better explosion resistance and higher safety than using only hydrogen reduction. (3) It can achieve the effect of preferential lithium extraction from discarded batteries and increase the recovery rate of lithium metal.

[0048] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present application, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present application.

Claims

1. A new method for preferentially extracting lithium from ternary mixed powder by water-gas catalytic reduction, characterized in that: The following steps are involved: Step 1: discharging, disassembling, crushing and screening the discarded ternary lithium batteries; Step 2, placing the powder in a calcining furnace and introducing water gas; Step 3, roasting at a certain temperature for a period of time under a water gas atmosphere; Step 4: After calcination, the material is cooled and then moved to a reactor, a certain amount of deionized water is added and stirred, and the reaction temperature and reaction time are controlled; Step 5, filtering and washing the reaction product to obtain a filtrate containing valuable metal lithium ions, wherein the contents of lithium, nickel, cobalt, manganese, and aluminum in the filtrate are 2.5-3 g / L, 0.5-1 mg / L, 1-3 mg / L, 5-8 mg / L, and 0.03-0.5 mg / L, respectively; Step 6: Evaporate and concentrate the filtrate to a certain concentration, adjust the pH, add sodium carbonate to precipitate lithium carbonate, and after high-temperature reaction, filter, wash, and dry to obtain battery-grade lithium carbonate.

2. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In the step 1, powders with a mesh size below 200 are selected by sieving.

3. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In step 2, at normal pressure, the flow rate is 2m 3 / h-4m 3 / h water gas is introduced and used as reducing agent.

4. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In the step 3, the calcination temperature is 550-700°C.

5. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In the step 3, the calcination time is 1.5-3h.

6. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In step 4, the solid content is 15%-30%, and the reaction temperature is 40-60°C.

7. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In step 4, the reaction time is 0.5-1h.

8. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In step 6, the lithium concentration of the concentrated solution is 15-30 g / L, the pH of the lithium-containing solution is 9-11, and the sodium carbonate concentration is 220-250 g / L. The reverse addition method is adopted, that is, the lithium-containing solution is added with the sodium carbonate solution.

9. The novel method for preferentially extracting lithium by ternary mixed powder by water-gas catalytic reduction as claimed in claim 1, characterized in that: In step 6, the temperature of precipitating lithium carbonate is 90-95° C., the feeding time is 50-80 min, and the reaction time is 30-60 min.

10. The novel method for preferentially extracting lithium by water-gas catalytic reduction of ternary mixed powder as claimed in claim 1, characterized in that: In step 6, the precipitated lithium carbonate is washed twice, the drying temperature is 100-140° C., and the drying time is 1-2 hours.

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