A waste lithium material recovery method and system based on ammonium chloride circulation

Abstract

The present invention provides a waste lithium material recovery system based on ammonium chloride circulation. The recovery system comprises: a waste lithium material leaching reaction tank, a pump, a waste lithium material leaching filter press, an impurity removal reaction tank, an impurity removal filter press, a pure lithium solution storage tank, a lithium carbonate synthesis reactor, a centrifuge, a drying tower, a crusher, a reaction mother liquor and washing liquid storage tank, an MVR evaporator, an evaporation mother liquor storage tank, a solid reactor, an ammonia storage tank, a carbon dioxide storage tank, and waste gas absorption and treatment equipment. Also provided is a waste lithium material recovery method based on ammonium chloride circulation. The present invention recycles ammonium chloride within the system, generates less waste throughout the production process, requires less purchased materials, and produces high-quality lithium carbonate that meets battery-grade standards. The entire process is environmentally friendly and low-cost.

Description

Technical Field

[0001] The present invention belongs to the field of battery manufacturing, and in particular relates to a waste lithium material recovery method and system based on ammonium chloride circulation. Background Art

[0002] Currently, lithium carbonate production primarily occurs through two methods: ore extraction and salt lake brine extraction. Ore extraction uses spodumene or lepidolite as raw materials. While spodumene extraction is a mature process, spodumene is primarily imported, and ore costs are controlled by foreign countries, resulting in high prices. Lepidolite has a low lithium content but high impurity content, making the extraction process complex and suitable for industrial-grade lithium carbonate production. Salt lake brine extraction is also used. Salt lakes are dynamic deposits of multiple mineral species and geological formations formed by multiple sources and factors. The brine contains high concentrations of chemicals such as potassium, boron, and magnesium, resulting in unstable raw material quality. Brine extraction is subject to significant environmental and technological constraints, making the production process difficult to control and resulting in significant fluctuations in both yield and quality. To date, lithium carbonate produced domestically through brine extraction is exclusively industrial-grade, requiring further purification to achieve battery-grade lithium carbonate. However, this production cost is higher than that of battery-grade lithium carbonate produced from ore extraction. The recycling of lithium-containing waste from chemical industries and lithium waste generated during the nickel and cobalt recovery process in lithium-ion batteries has taken off relatively recently.

[0003] Although some prior art technologies for recycling waste lithium have been disclosed, these processes generate large amounts of industrial salt and require a large amount of auxiliary materials. To address this issue, the present invention circulates ammonium chloride within the system during the recovery of waste lithium, reducing waste emissions and the need for external material purchases. Summary of the Invention

[0004] The present invention aims to provide a waste lithium material recovery method and system based on ammonium chloride circulation. The present invention recycles ammonium chloride in the system, generates less waste in the entire production process, requires less material to be purchased, and produces high-quality lithium carbonate that meets the standards of battery-grade lithium carbonate. The entire process is environmentally friendly and low-cost.

[0005] On the one hand, the present invention provides a waste lithium material recovery system based on ammonium chloride circulation, the recovery system comprising: a leaching reaction tank, a filter press, an impurity removal reaction tank, an impurity removal filter press, a pure lithium solution storage tank, a lithium carbonate synthesis reactor, a centrifuge, a drying tower, a crusher, a mother liquor and washing liquid storage tank, an MVR evaporator, an evaporated mother liquor storage tank, a solid reactor, an ammonia storage tank, a carbon dioxide storage tank, and waste gas absorption and treatment equipment;

[0006] The outlet of the leaching reaction tank is connected to the inlet of the filter press by a pump, the outlet of the filter press is connected to the inlet of the impurity removal reaction tank, the outlet of the impurity removal reaction tank is connected to the inlet of the impurity removal filter press by a pump, the outlet of the impurity removal filter press is connected to the inlet of the pure lithium solution storage tank, the outlet of the pure lithium solution storage tank is connected to the inlet of the lithium carbonate synthesis reactor by a pump, the outlets of the ammonia storage tank and the carbon dioxide storage tank are connected to the inlet of the lithium carbonate synthesis reactor, the outlet of the ammonia storage tank is also connected to the impurity removal reaction tank, the outlet of the lithium carbonate synthesis reactor is connected to the inlet of the centrifuge, and the liquid outlet of the centrifuge is connected to the mother liquor and the washing liquid. The inlet of the liquid storage tank and the outlet of the mother liquor and washing liquid storage tank are connected to the inlet of the MVR evaporator through a pump, the liquid outlet of the MVR evaporator is connected to the inlet of the evaporation mother liquor storage tank, the outlet of the evaporation mother liquor storage tank is connected to the inlet of the impurity removal reaction tank through a pump, the solid outlet of the MVR evaporator is connected to the inlet of the solid reactor, the gas outlet of the solid reactor is connected to the ammonia storage tank, the outlet of the solid reactor is also connected to the leaching reaction tank, the solid outlet of the centrifuge is connected to the inlet of the drying tower, the outlet of the drying tower is connected to the inlet of the crusher, and the absorption inlet of the waste gas absorption and treatment equipment is the impurity removal reaction tank and the impurity removal filter press.

[0007] Preferably, both the lithium carbonate synthesis reactor and the solid reactor have heating systems.

[0008] Preferably, metering instruments are installed between the pure lithium solution storage tank and the lithium carbonate synthesis reactor, between the ammonia storage tank and the lithium carbonate synthesis reactor, and between the carbon dioxide storage tank and the lithium carbonate reactor.

[0009] Another aspect of the present invention provides a method for recovering waste lithium materials based on ammonium chloride circulation, comprising the following steps:

[0010] Step 1, slurrying the waste lithium material and water in a leaching reaction tank at a solid-liquid ratio of 1:2-1:10, adding calcium chloride for reaction, filtering with a filter press to obtain a lithium solution and calcium residue, and the lithium solution enters an impurity removal reaction tank;

[0011] Step 2: adding ammonia to the impurity removal reaction tank to adjust the pH value of the lithium solution to 9-12, filtering with an impurity removal filter press to obtain a pure lithium solution, and the pure lithium solution enters the lithium carbonate synthesis reactor;

[0012] Step 3: Add pure lithium solution to the lithium carbonate synthesis reactor, and introduce ammonia and carbon dioxide to react at the same time. The centrifuge obtains lithium carbonate and mother liquor, and the mother liquor enters the mother liquor and washing liquid storage tank;

[0013] Step 4: The lithium carbonate obtained in step 3 is washed in a centrifuge, dried in a drying tower, and crushed in a crusher to obtain battery-grade lithium carbonate, and the washing water enters the mother liquor and washing liquid storage tanks;

[0014] In step 5, the mother liquor obtained in step 3 and the washing water obtained in step 4 are transferred to the MVR evaporator through the mother liquor and washing liquid storage tank, and ammonium chloride crystals and evaporated mother liquor are obtained by evaporation and crystallization;

[0015] Step 6: The evaporated mother liquor is transported to the impurity removal reaction tank by a pump and returns to step 2 for impurity removal;

[0016] Step 7: Add ammonium chloride crystals to the solid reactor, and at the same time, add calcium hydroxide to the solid reactor, mix evenly, heat and react, and the generated ammonia enters the ammonia storage tank. Return to steps 2 and 3, and the calcium chloride generated by the reaction returns to step 1.

[0017] Preferably, in step 1, the waste lithium material includes waste lithium fluoride, waste lithium phosphate, and waste lithium carbonate.

[0018] Preferably, in step 1, the amount of calcium chloride added is 0.5-0.6 times the amount of lithium, and the reaction is carried out for 1-10 hours.

[0019] Preferably, in step 3, ammonia and carbon dioxide are added to the pure lithium solution to react for 1-10 hours.

[0020] Preferably, in step 7, ammonium chloride crystals and calcium hydroxide are added to the reactor in a molar ratio of 1:1, mixed evenly, heated to 70-200° C., and reacted for 1-10 hours.

[0021] The present invention has the following beneficial effects:

[0022] The present invention recycles ammonium chloride in the system, generates less waste in the entire production process, requires less materials to be purchased, and produces high-quality lithium carbonate that meets the standards of battery-grade lithium carbonate. The entire process is environmentally friendly and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 is a schematic diagram of a recovery system of the present invention; DETAILED DESCRIPTION

[0025] The following detailed description of the present application will make the features and advantages of the present application clearer and more explicit.

[0026] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "front," "back," "left," and "right" and the like indicate positions or locations based on the operating state of this application. These terms are intended only to facilitate the description of this application and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0028] This embodiment provides a waste lithium material recovery system based on ammonium chloride circulation, the recovery system comprising: a leaching reaction tank, a filter press, an impurity removal reaction tank, an impurity removal filter press, a pure lithium solution storage tank, a lithium carbonate synthesis reactor, a centrifuge, a drying tower, a crusher, a mother liquor and washing liquid storage tank, an MVR evaporator, an evaporated mother liquor storage tank, a solid reactor, an ammonia storage tank, a carbon dioxide storage tank, and waste gas absorption and treatment equipment;

[0029] The outlet of the leaching reaction tank is connected to the inlet of the filter press by a pump, the outlet of the filter press is connected to the inlet of the impurity removal reaction tank, the outlet of the impurity removal reaction tank is connected to the inlet of the impurity removal filter press by a pump, the outlet of the impurity removal filter press is connected to the inlet of the pure lithium solution storage tank, the outlet of the pure lithium solution storage tank is connected to the inlet of the lithium carbonate synthesis reactor by a pump, the outlets of the ammonia storage tank and the carbon dioxide storage tank are connected to the inlet of the lithium carbonate synthesis reactor, the outlet of the ammonia storage tank is also connected to the impurity removal reaction tank, the outlet of the lithium carbonate synthesis reactor is connected to the inlet of the centrifuge, and the liquid outlet of the centrifuge is connected to the mother liquor and the washing liquid. The inlet of the liquid storage tank and the outlet of the mother liquor and washing liquid storage tank are connected to the inlet of the MVR evaporator through a pump, the liquid outlet of the MVR evaporator is connected to the inlet of the evaporation mother liquor storage tank, the outlet of the evaporation mother liquor storage tank is connected to the inlet of the impurity removal reaction tank through a pump, the solid outlet of the MVR evaporator is connected to the inlet of the solid reactor, the gas outlet of the solid reactor is connected to the ammonia storage tank, the outlet of the solid reactor is also connected to the leaching reaction tank, the solid outlet of the centrifuge is connected to the inlet of the drying tower, the outlet of the drying tower is connected to the inlet of the crusher, and the absorption inlet of the waste gas absorption and treatment equipment is the impurity removal reaction tank and the impurity removal filter press.

[0030] In this embodiment, both the lithium carbonate synthesis reactor and the solid reactor have heating systems.

[0031] In this embodiment, metering instruments are installed between the pure lithium solution storage tank and the lithium carbonate synthesis reactor, between the ammonia storage tank and the lithium carbonate synthesis reactor, and between the carbon dioxide storage tank and the lithium carbonate reactor.

[0032] Example 1

[0033] A method for recovering waste lithium materials based on ammonium chloride circulation comprises the following steps:

[0034] Step 1, slurrying the waste lithium material and water in a leaching reaction tank at a solid-liquid ratio of 1:2, adding calcium chloride to react, filtering with a filter press to obtain a lithium solution and calcium residue, and the lithium solution enters an impurity removal reaction tank;

[0035] Step 2: adding ammonia to the impurity removal reaction tank to adjust the pH value of the lithium solution to 9, filtering with an impurity removal filter press to obtain a pure lithium solution, and the pure lithium solution enters the lithium carbonate synthesis reactor;

[0036] Step 3: Add pure lithium solution to the lithium carbonate synthesis reactor, and introduce ammonia and carbon dioxide to react at the same time. The centrifuge obtains lithium carbonate and mother liquor, and the mother liquor enters the mother liquor and washing liquid storage tank;

[0037] Step 4: The lithium carbonate obtained in step 3 is washed in a centrifuge, dried in a drying tower, and crushed in a crusher to obtain battery-grade lithium carbonate, and the washing water enters the mother liquor and washing liquid storage tanks;

[0038] In step 5, the mother liquor obtained in step 3 and the washing water obtained in step 4 are transferred to the MVR evaporator through the mother liquor and washing liquid storage tank, and ammonium chloride crystals and evaporated mother liquor are obtained by evaporation and crystallization;

[0039] Step 6: The evaporated mother liquor is transported to the impurity removal reaction tank by a pump and returns to step 2 for impurity removal;

[0040] Step 7: Add ammonium chloride crystals to the solid reactor, and at the same time, add calcium hydroxide to the solid reactor, mix evenly, heat and react, and the generated ammonia enters the ammonia storage tank. Return to steps 2 and 3, and the calcium chloride generated by the reaction returns to step 1.

[0041] In this embodiment, in step 1, the waste lithium material includes waste lithium fluoride, waste lithium phosphate, and waste lithium carbonate.

[0042] In this embodiment, in step 1, the amount of calcium chloride added is 0.5 times the amount of lithium, and the reaction is carried out for 10 hours.

[0043] In this embodiment, in step 3, ammonia and carbon dioxide are added to the pure lithium solution and reacted for 10 hours.

[0044] In this embodiment, in step 7, ammonium chloride crystals and calcium hydroxide are added to a reactor at a molar ratio of 1:1, mixed evenly, heated to 70° C., and reacted for 10 hours.

[0045] Example 2

[0046] A method for recovering waste lithium materials based on ammonium chloride circulation comprises the following steps:

[0047] Step 1, slurrying the waste lithium material and water in a leaching reaction tank at a solid-liquid ratio of 1:10, adding calcium chloride to react, filtering with a filter press to obtain a lithium solution and calcium residue, and the lithium solution enters an impurity removal reaction tank;

[0048] Step 2: adding ammonia to the impurity removal reaction tank to adjust the pH value of the lithium solution to 12, filtering with an impurity removal filter press to obtain a pure lithium solution, and the pure lithium solution enters the lithium carbonate synthesis reactor;

[0049] Step 3: Add pure lithium solution to the lithium carbonate synthesis reactor, and introduce ammonia and carbon dioxide to react at the same time. The centrifuge obtains lithium carbonate and mother liquor, and the mother liquor enters the mother liquor and washing liquid storage tank;

[0050] Step 4: The lithium carbonate obtained in step 3 is washed in a centrifuge, dried in a drying tower, and crushed in a crusher to obtain battery-grade lithium carbonate, and the washing water enters the mother liquor and washing liquid storage tanks;

[0051] In step 5, the mother liquor obtained in step 3 and the washing water obtained in step 4 are transferred to the MVR evaporator through the mother liquor and washing liquid storage tank, and ammonium chloride crystals and evaporated mother liquor are obtained by evaporation and crystallization;

[0052] Step 6: The evaporated mother liquor is transported to the impurity removal reaction tank by a pump and returns to step 2 for impurity removal;

[0053] Step 7: Add ammonium chloride crystals to the solid reactor, and at the same time, add calcium hydroxide to the solid reactor, mix evenly, heat and react, and the generated ammonia enters the ammonia storage tank. Return to steps 2 and 3, and the calcium chloride generated by the reaction returns to step 1.

[0054] In this embodiment, in step 1, the waste lithium material includes waste lithium fluoride, waste lithium phosphate, and waste lithium carbonate.

[0055] In this embodiment, in step 1, the amount of calcium chloride added is 0.6 times the amount of lithium, and the reaction is carried out for 1 hour.

[0056] In this embodiment, in step 3, ammonia and carbon dioxide are added to the pure lithium solution and reacted for 1 hour.

[0057] In this embodiment, in step 7, ammonium chloride crystals and calcium hydroxide are added to a reactor at a molar ratio of 1:1, mixed evenly, heated to 200° C., and reacted for 1 hour.

[0058] Example 3

[0059] A method for recovering waste lithium materials based on ammonium chloride circulation comprises the following steps:

[0060] Step 1, slurrying the waste lithium material and water in a leaching reaction tank at a solid-liquid ratio of 1:5, adding calcium chloride to react, filtering with a filter press to obtain a lithium solution and calcium residue, and the lithium solution enters an impurity removal reaction tank;

[0061] Step 2: adding ammonia to the impurity removal reaction tank to adjust the pH value of the lithium solution to 10, filtering with an impurity removal filter press to obtain a pure lithium solution, and the pure lithium solution enters the lithium carbonate synthesis reactor;

[0062] Step 3: Add pure lithium solution to the lithium carbonate synthesis reactor, and introduce ammonia and carbon dioxide to react at the same time. The centrifuge obtains lithium carbonate and mother liquor, and the mother liquor enters the mother liquor and washing liquid storage tank;

[0063] Step 4: The lithium carbonate obtained in step 3 is washed in a centrifuge, dried in a drying tower, and crushed in a crusher to obtain battery-grade lithium carbonate, and the washing water enters the mother liquor and washing liquid storage tanks;

[0064] In step 5, the mother liquor obtained in step 3 and the washing water obtained in step 4 are transferred to the MVR evaporator through the mother liquor and washing liquid storage tank, and ammonium chloride crystals and evaporated mother liquor are obtained by evaporation and crystallization;

[0065] Step 6: The evaporated mother liquor is transported to the impurity removal reaction tank by a pump and returns to step 2 for impurity removal;

[0066] Step 7: Add ammonium chloride crystals to the solid reactor, and at the same time, add calcium hydroxide to the solid reactor, mix evenly, heat and react, and the generated ammonia enters the ammonia storage tank. Return to steps 2 and 3, and the calcium chloride generated by the reaction returns to step 1.

[0067] In this embodiment, in step 1, the waste lithium material includes waste lithium fluoride, waste lithium phosphate, and waste lithium carbonate.

[0068] In this embodiment, in step 1, the amount of calcium chloride added is 0.5 times the amount of lithium, and the reaction is carried out for 5 hours.

[0069] In this embodiment, in step 3, ammonia and carbon dioxide are added to the pure lithium solution and reacted for 5 hours.

[0070] In this embodiment, in step 7, ammonium chloride crystals and calcium hydroxide are added to a reactor at a molar ratio of 1:1, mixed evenly, heated to 100° C., and reacted for 5 hours.

[0071] The present application has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present application, all of which fall within the scope of the present application. The scope of protection of the present application shall be determined by the appended claims.

Claims

1. A waste lithium material recovery system based on ammonium chloride circulation, characterized in that: The recovery system includes: a leaching reaction tank, a filter press, an impurity removal reaction tank, an impurity removal filter press, a pure lithium solution storage tank, a lithium carbonate synthesis reactor, a centrifuge, a drying tower, a crusher, a mother liquor and washing liquid storage tank, an MVR evaporator, an evaporation mother liquor storage tank, a solid reactor, an ammonia storage tank, a carbon dioxide storage tank, and waste gas absorption and treatment equipment; The outlet of the leaching reaction tank is connected to the inlet of the filter press by a pump, the outlet of the filter press is connected to the inlet of the impurity removal reaction tank, the outlet of the impurity removal reaction tank is connected to the inlet of the impurity removal filter press by a pump, the outlet of the impurity removal filter press is connected to the inlet of the pure lithium solution storage tank, the outlet of the pure lithium solution storage tank is connected to the inlet of the lithium carbonate synthesis reactor by a pump, the outlets of the ammonia storage tank and the carbon dioxide storage tank are connected to the inlet of the lithium carbonate synthesis reactor, the outlet of the ammonia storage tank is also connected to the impurity removal reaction tank, the outlet of the lithium carbonate synthesis reactor is connected to the inlet of the centrifuge, and the liquid outlet of the centrifuge is connected to the mother liquor and the washing liquid. The inlet of the liquid storage tank and the outlet of the mother liquor and washing liquid storage tank are connected to the inlet of the MVR evaporator through a pump, the liquid outlet of the MVR evaporator is connected to the inlet of the evaporation mother liquor storage tank, the outlet of the evaporation mother liquor storage tank is connected to the inlet of the impurity removal reaction tank through a pump, the solid outlet of the MVR evaporator is connected to the inlet of the solid reactor, the gas outlet of the solid reactor is connected to the ammonia storage tank, the outlet of the solid reactor is also connected to the leaching reaction tank, the solid outlet of the centrifuge is connected to the inlet of the drying tower, the outlet of the drying tower is connected to the inlet of the crusher, and the absorption inlet of the waste gas absorption and treatment equipment is the impurity removal reaction tank and the impurity removal filter press.

2. A waste lithium material recovery system based on ammonium chloride circulation according to claim 1, characterized in that: Both the lithium carbonate synthesis reactor and the solid reactor are provided with a heating system.

3. A waste lithium material recovery system based on ammonium chloride circulation according to claim 1, characterized in that: Measuring instruments are installed between the pure lithium solution storage tank and the lithium carbonate synthesis reactor, between the ammonia storage tank and the lithium carbonate synthesis reactor, and between the carbon dioxide storage tank and the lithium carbonate reactor.

4. A waste lithium material recovery method based on ammonium chloride circulation, characterized in that: The following steps are involved: Step 1, slurrying the waste lithium material and water in a leaching reaction tank at a solid-liquid ratio of 1:2-1:10, adding calcium chloride for reaction, filtering with a filter press to obtain a lithium solution and calcium residue, and the lithium solution enters an impurity removal reaction tank; Step 2: adding ammonia to the impurity removal reaction tank to adjust the pH value of the lithium solution to 9-12, filtering with an impurity removal filter press to obtain a pure lithium solution, and the pure lithium solution enters the lithium carbonate synthesis reactor; Step 3: adding a pure lithium solution to a lithium carbonate synthesis reactor, while introducing ammonia and carbon dioxide to react, using a centrifuge to wash to obtain lithium carbonate and mother liquor, and the mother liquor enters a mother liquor and washing liquid storage tank; Step 4: The lithium carbonate obtained in step 3 is washed in a centrifuge, dried in a drying tower, and crushed in a crusher to obtain battery-grade lithium carbonate, and the washing water enters the mother liquor and washing liquid storage tanks; In step 5, the mother liquor obtained in step 3 and the washing water obtained in step 4 are transferred to the MVR evaporator through the mother liquor and washing liquid storage tank, and ammonium chloride crystals and evaporated mother liquor are obtained by evaporation and crystallization; Step 6: The evaporated mother liquor is transported to the impurity removal reaction tank by a pump and returns to step 2 for impurity removal; Step 7: Add ammonium chloride crystals to the solid reactor, and at the same time, add calcium hydroxide to the solid reactor, mix evenly, heat and react, and the generated ammonia enters the ammonia storage tank. Return to steps 2 and 3, and the calcium chloride generated by the reaction returns to step 1.

5. A method for recovering waste lithium materials based on ammonium chloride circulation according to claim 4, characterized in that: In step 1, the waste lithium materials include waste lithium fluoride, waste lithium phosphate, and waste lithium carbonate.

6. A method for recovering waste lithium materials based on ammonium chloride circulation according to claim 4, characterized in that: In step 1, the amount of calcium chloride added is 0.5-0.6 times the amount of lithium, and the reaction is carried out for 1-10 hours.

7. A method for recovering waste lithium materials based on ammonium chloride circulation according to claim 4, characterized in that: In step 3, ammonia and carbon dioxide are added to the pure lithium solution to react for 1-10 hours.

8. A method for recovering waste lithium materials based on ammonium chloride circulation according to claim 4, characterized in that: In step 7, ammonium chloride crystals and calcium hydroxide are added to a reactor in a molar ratio of 1:1, mixed evenly, heated to 70-200° C., and reacted for 1-10 hours.

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