A continuous preparation device of lithium carbonate

Abstract

The utility model discloses a continuous preparation device for lithium carbonate, which comprises raw material storage tanks, a mixer, a reactor and a solid-liquid separator connected in sequence, wherein the raw material storage tanks comprise lithium salt storage tanks and carbonate storage tanks; and the solid-liquid separator is an inorganic ceramic membrane group. The device is mature and reliable, and the continuous arrangement of the mixer and the reactor can ensure the uniformity of the particle size of the product, thereby obtaining high-quality lithium carbonate products. The battery-grade lithium carbonate produced is very suitable for use in solid-state battery positive electrode materials, and has great potential economic benefits.

Description

Technical Field

[0001] This utility model relates to the field of battery material preparation equipment technology, and in particular to an apparatus for continuously preparing battery-grade lithium carbonate. Background Technology

[0002] Lithium carbonate is an important cathode material for lithium-ion batteries, and its production currently mainly involves two methods: sodium carbonate carbonation and carbon dioxide carbonation. Most industrial equipment uses lithium sulfate and sodium carbonate for carbonation. However, due to the rapid precipitation reaction between lithium sulfate and sodium carbonate upon contact, it is difficult to achieve uniform mixing in large-volume reaction vessels. This leads to problems such as defects, dendrites, and impurity encapsulation during crystal growth, resulting in products with uneven particle size distribution, unstable dispersibility, and high levels of impurities such as sulfate, making it difficult to produce high-quality battery-grade lithium carbonate. Utility Model Content

[0003] This invention provides a continuous lithium carbonate preparation apparatus to solve the technical problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows: A continuous lithium carbonate production apparatus includes a raw material storage tank, a mixer, a reactor, and a solid-liquid separator connected in sequence. The raw material storage tank includes a lithium salt storage tank and a carbonate storage tank; the solid-liquid separator is an inorganic ceramic membrane module. Before reaching the optimal reaction temperature, the raw material first generates a portion of seed crystals in the mixer and is thoroughly mixed. The suspension, rich in seed crystals and with uniform material distribution, flows through the reactor and is heated to the optimal reaction temperature, where relatively uniform crystal growth occurs. This controls the average particle size of the product, thereby reducing defects, dendrites, and impurity encapsulation, resulting in a high-quality lithium carbonate product.

[0005] As a further preferred embodiment of the above technical solution, the inorganic ceramic membrane module comprises several inorganic ceramic membrane modules connected in parallel, and the pore size of the inorganic ceramic membrane is 10 nm. When the number of membranes in the inorganic ceramic membrane module (proportional to the membrane area) is sufficiently large, the operating pressure required for solid-liquid separation becomes lower, the material flow rate becomes slower, and better solid-liquid separation and washing effects can be achieved.

[0006] As a further preferred embodiment of the above technical solution, a preheater is also provided between the raw material storage tank and the mixer to preheat the raw material output from the raw material storage tank. The preheater can preheat the raw material output from the raw material storage tank to the optimal nucleation temperature before it enters the mixer, thereby increasing the quantity and effectiveness of net weight formation in the mixer and ensuring the smooth growth of crystals in the subsequent reactor.

[0007] As a further preferred embodiment of the above technical solution, the material outlet of the reactor is divided into two paths: one path leads to the feed inlet of the solid-liquid separator, and the other path returns to the feed inlet of the mixer. The material outlet of the reactor is also equipped with valves for selecting the material destination and for controlling the flow rate.

[0008] As a further preferred embodiment of the above technical solution, a scrubber is also included, wherein the solid outlet of the solid-liquid separator is connected to the feed inlet of the scrubber, and the discharge outlet of the scrubber is connected to the feed inlet of the scrubber.

[0009] As a further preferred embodiment of the above technical solution, the solid outlet of the solid-liquid separator is also connected to a centrifuge.

[0010] This utility model has the following beneficial effects: The equipment of this invention is mature and reliable. The continuous arrangement of the mixer and reactor can ensure the uniformity of the product particle size, thereby obtaining high-quality lithium carbonate products. The battery-grade lithium carbonate produced is very suitable for use as a cathode material in solid-state batteries and has huge potential economic benefits. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the continuous lithium carbonate preparation apparatus of Example 1.

[0012] Legend: 1. Mixer; 2. Reactor; 3. Solid-liquid separator; 4. Lithium salt storage tank; 5. Carbonate storage tank; 6. Preheater; 7. Scrubber; 8. Centrifuge. Detailed Implementation

[0013] The present invention will be described in detail below with reference to the embodiments and accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0014] Example 1: The continuous lithium carbonate preparation apparatus of this embodiment, such as... Figure 1 As shown, it includes a raw material storage tank, a mixer 1 (static mixer), a reactor 2 and a solid-liquid separator 3 connected in sequence. The raw material storage tank includes a lithium salt storage tank 4 and a carbonate storage tank 5; the solid-liquid separator 3 is an inorganic ceramic membrane module.

[0015] In this embodiment, the inorganic ceramic membrane assembly includes several inorganic ceramic membranes connected in parallel, and the pore size of the inorganic ceramic membranes is 10 nm.

[0016] In this embodiment, a preheater 6 is also provided between the raw material storage tank and the mixer for preheating the raw materials output from the raw material storage tank.

[0017] In this embodiment, the material outlet of reactor 2 is divided into two paths: one path goes to the feed inlet of solid-liquid separator 3, and the other path returns to the feed inlet of mixer 1. The material outlet of reactor 2 is also equipped with valves for selecting the material destination and for controlling the flow rate.

[0018] In this embodiment, the continuous lithium carbonate preparation apparatus further includes a scrubber 7 (pulping tank), the solid outlet of the solid-liquid separator 3 is connected to the feed inlet of the scrubber 7, and the discharge outlet of the scrubber 7 is connected to the feed inlet of the solid-liquid separator 3.

[0019] In this embodiment, the solid outlet of the solid-liquid separator 3 is also connected to the feed inlet of the centrifuge 8.

[0020] In this embodiment, the discharge port of the washer 7 is also connected to the inlet of the solid-liquid separator 3.

[0021] The preparation of lithium carbonate using the continuous lithium carbonate preparation apparatus of this embodiment includes the following steps: (1) First, the raw material lithium sulfate solution is stored in lithium salt storage tank 4 and then pumped to preheater 6 for preheating via lithium sulfate transfer pump. The preheating temperature of the lithium sulfate solution should not exceed 80℃.

[0022] (2) The raw material sodium carbonate solution is stored in a carbonate storage tank and then pumped to preheater 6 for preheating. The preheating temperature of the sodium carbonate solution should not exceed 40°C.

[0023] (3) The fully preheated lithium sulfate and sodium carbonate solutions are fed into static mixer 1 in proportion for uniform mixing. The proportion is controlled by DCS interlock control. The input proportion can be adjusted according to the concentration of lithium sulfate and sodium carbonate solutions. Generally, a lithium sulfate:sodium carbonate molar ratio of 2:1.05 is preferred.

[0024] (4) The uniformly mixed liquid flows into reactor 2. Reactor 2 is heated by a jacket, producing a large amount of lithium carbonate precipitate. To control the reaction temperature of the material, the steam valve in the jacket can be interlocked with the reactor outlet temperature via DCS. The suitable reactor outlet temperature is 95℃. To ensure the material reacts and ages fully, the flow rate can be controlled by the reactor outlet valve to increase the material residence time; alternatively, the material can be returned to the static mixer 1 by switching valves for internal circulation, ensuring the material reacts completely and improving the yield. The suitable material residence time is generally not less than 1 hour. The product D50 decreases as time decreases. When the material residence time is 2 hours, D50 is 5-7 micrometers; when the material residence time is 1 hour, D50 is 4-8 micrometers; and when the material residence time is 0.5 hours, D50 is 4-9 micrometers.

[0025] (5) The lithium carbonate precipitate from reactor 2 is pumped under pressure and fed into an inorganic ceramic membrane module (F-Ni(i=n)). Under pressure, solid-liquid separation occurs. The filtrate is sent to the mother liquor treatment, and the slurry flows into the scrubber 7. The suitable pore size of the inorganic ceramic membrane is 10 nm, and the suitable operating pressure is 0.3 mPa.

[0026] (6) The lithium carbonate slurry in the scrubber 7 is thoroughly stirred and washed with pure water. The washed slurry is then sent back to the inorganic ceramic membrane module (F-Ni(i=n)) via a filter press pump for secondary solid-liquid separation. The wash water enters the filtrate pipe, and the slurry flows into the centrifuge 8 for dehydration. Subsequently, the lithium carbonate product can be obtained through drying and packaging. During pulping and washing, the suitable slurry:water ratio is 30%:70% by mass. As the wash water increases, the sulfate content of the product decreases. When the wash water accounts for 50% of the slurry, the sulfate content of the product is 450 ppm; when the wash water accounts for 70% of the slurry, the sulfate content of the product is 550 ppm.

[0027] The above description is merely a preferred embodiment of this utility model, and the protection scope of this utility model is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the technical concept of this utility model should also be considered within the protection scope of this utility model.

[0028] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A continuous lithium carbonate preparation apparatus, characterized in that, It includes a raw material storage tank, a mixer (1), a reactor (2) and a solid-liquid separator (3) connected in sequence. The raw material storage tank includes a lithium salt storage tank (4) and a carbonate storage tank (5). The solid-liquid separator (3) is an inorganic ceramic membrane module.

2. The continuous lithium carbonate preparation apparatus according to claim 1, characterized in that, The inorganic ceramic membrane assembly comprises several inorganic ceramic membranes connected in parallel, and the pore size of the inorganic ceramic membranes is 10 nm.

3. The continuous lithium carbonate preparation apparatus according to claim 1, characterized in that, A preheater (6) is also provided between the raw material storage tank and the mixer (1) for preheating the raw materials output from the raw material storage tank.

4. The continuous lithium carbonate preparation apparatus according to claim 1, characterized in that, The material outlet of the reactor (2) is divided into two paths: one path goes to the feed inlet of the solid-liquid separator (3), and the other path returns to the feed inlet of the mixer (1). The material outlet of the reactor (2) is also equipped with valves for selecting the material destination and for controlling the flow rate.

5. The continuous lithium carbonate preparation apparatus according to any one of claims 1-4, characterized in that, It also includes a scrubber (7), the solid outlet of the solid-liquid separator (3) is connected to the feed inlet of the scrubber (7), and the discharge outlet of the scrubber (7) is connected to the feed inlet of the scrubber (7).

6. The continuous lithium carbonate preparation apparatus according to claim 5, characterized in that, The solid outlet of the solid-liquid separator (3) is also connected to a centrifuge (8).

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