A lithium sulfate purification system

Abstract

The utility model relates to lithium sulfate production technical field, aiming at the problem that the silicon content in lithium sulfate purification liquid is too high or the silicon content in purification liquid is unstable in the industrial production of lithium salt at present, specifically discloses a kind of lithium sulfate purification system, along the direction of lithium sulfate purification liquid flow, including the main filter system and secondary filter system of sequential intercommunication, the feed end of main filter system is also equipped with lithium hydraulic filter press, the discharge end of secondary filter system is also connected with leaching solution tank;The main filter system includes the main filter tank and filter primary filter press of sequential intercommunication, and the feed end of main filter tank is provided with lime feed pipe, by the improvement of purification system, can reduce artificial intervention dependence, improve production continuity, effectively control the silicon content in purification liquid always keep low and stable level, and convenient operation, high working efficiency.

Description

Technical Field

[0001] This utility model relates to the field of lithium sulfate production technology, and more specifically, to a lithium sulfate purification system. Background Technology

[0002] The industrial production of lithium salts such as lithium carbonate and lithium hydroxide involves the following steps: ore roasting, acid leaching, solid-liquid separation, lime purification, precipitation purification, filtration purification, and product conversion. The purification solution used in the filtration purification stage is primarily a lithium sulfate solution, which typically still contains residual sodium (Na₂O). + K + Lithium sulfate, containing impurities such as silicon, is a reactant used in the subsequent production and preparation of lithium salts such as lithium carbonate or lithium hydroxide. Therefore, the purity of the purification solution directly affects the quality of lithium salt products.

[0003] Given the above situation, how to reduce the impurity content in the purification solution and maintain the stability of the purification solution's purity has become an important issue in improving the quality of lithium salts. For example, patent CN209853763U provides a purification liquid treatment system for a lithium carbonate production process, including a lithium sulfate leachate storage tank, a pH adjustment tank, a precision filter, an absorption tower, a heat exchanger, an ultrafiltration membrane filter, a reverse osmosis membrane filter, a reaction tank, a feeding tank, a plate and frame filter, and a collection tank. The outlet of the lithium sulfate leachate storage tank is connected to the inlet of the pH adjustment tank via a pipeline. The outlet of the pH adjustment tank is connected to the inlet of the precision filter via a pipeline. The outlet of the precision filter is connected to the inlet of the absorption tower via a pipeline. The outlet of the absorption tower is connected to the shell-side inlet of the heat exchanger via a pipeline. The shell-side outlet of the heat exchanger is connected to the inlet of the ultrafiltration membrane filter via a pipeline. The outlet of the ultrafiltration membrane filter is connected to the inlet of the reverse osmosis membrane filter via a pipeline. The outlet of the reverse osmosis membrane filter is connected to the inlet of the reaction tank via a pipeline. The outlet of the reaction tank is connected to the inlet of the plate and frame filter via a pipeline. The outlet of the plate and frame filter is connected to the inlet of the collection tank via a pipeline. The outlet of the feeding tank is connected to the inlet of the reaction tank via a pipeline.

[0004] In existing methods for treating lithium sulfate purification solutions, lime is typically added, followed by multiple filtrations to remove impurities such as Ga, Fe, and Al through precipitation. However, practical applications have revealed that these methods result in problems such as excessively high silicon content and unstable purity in the purification solution. Utility Model Content

[0005] The purpose of this invention is to solve the problems of excessively high or unstable silicon content in lithium sulfate purification solutions during current industrial lithium salt production. This application provides a lithium sulfate purification system that, through improvements to the system, reduces reliance on manual intervention, enhances production continuity, and effectively controls the silicon content in the purification solution to remain at a consistently low and stable level.

[0006] This utility model is achieved through the following technical solution:

[0007] This utility model provides a lithium sulfate purification system, which includes a main filtration system and a secondary filtration system connected in sequence along the flow direction of the lithium sulfate purification liquid. The feed end of the main filtration system is also equipped with a lithium hydraulic filter, and the discharge end of the secondary filtration system is also connected to a leachate tank. The feed end of the main filtration system is equipped with a lime feed pipe.

[0008] Preferably, the main perforation filtration system includes a main perforation trough and a primary perforation filter press connected in sequence. The feed end of the lime feed pipe is inserted through the feed end of the main perforation trough, and the feed end of the main perforation trough is also connected to the discharge end of the lithium hydraulic filter press through a pipe. The discharge end of the primary perforation filter press is connected to the feed end of the secondary perforation filtration system.

[0009] Preferably, the inner cavity of the main filter tank is equipped with a stirring mechanism, which is located between the discharge end of the lime feed pipe and the discharge end of the main filter tank.

[0010] Preferably, the stirring mechanism includes a filter-penetrating stirring rod and a plurality of stirring paddles surrounding the side wall of the filter-penetrating stirring rod, wherein the filter-penetrating stirring rod extends vertically through the bottom of the main filter-penetrating tank, and a drive motor is provided at the end of the filter-penetrating stirring rod that extends through the main filter-penetrating tank, and the end of the filter-penetrating stirring rod is detachably connected to the through shaft of the drive motor.

[0011] Preferably, the secondary filtration system includes a secondary filtration tank and a secondary filtration filter press connected in sequence. The feed end of the secondary filtration tank is connected to the discharge end of the primary filtration filter press, and the discharge end of the secondary filtration filter press is connected to the feed end of the leachate tank.

[0012] Preferably, a drain pipe is installed at the bottom of the secondary filter tank.

[0013] Preferably, the side wall of the leaching tank is provided with an electric heating mechanism, which includes an electric heating tube and a power supply. The electric heating tube is embedded in the side wall of the leaching tank and is electrically connected to the power supply.

[0014] Preferably, the inner cavity of the leaching tank is equipped with a mixing mechanism, which includes a mixing shaft and a spiral stirring blades wound around the side wall of the mixing shaft. The mixing shaft is vertically inserted through the top of the leaching tank, and a rotating motor is configured at the end of the mixing shaft that extends out of the top of the leaching tank. The end of the mixing shaft is detachably connected to the through shaft of the rotating motor.

[0015] The technical solution of this utility model has the following beneficial effects:

[0016] Through research and experimental verification, this invention has found that the excessive silicon content in existing purification solutions is mainly due to the large amount of silicon dissolved in the lithium slag under alkaline conditions. Adding pH adjusters to regulate the acidity or alkalinity of the solution leads to unstable pH values, causing significant fluctuations in silicon content and ultimately resulting in low purity of the final product. This invention, through improvements to the purification system, reduces reliance on manual intervention, enhances production continuity, effectively controls the silicon content in the purification solution to remain at a low and stable level, and is convenient to operate with high efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the lithium sulfate purification system in Example 1;

[0018] Figure 2 This is a cross-sectional view of the main filter channel in Example 1;

[0019] Figure 3 This is a cross-sectional view of the leaching tank in Example 1.

[0020] Reference numerals: 1-Lithium hydraulic filter press, 2-Main filter tank, 21-Lime feed pipe, 22-Filter stirring rod, 23-Agitator, 24-Drive motor, 3-Primary filter press, 4-Secondary filter tank, 41-Drain pipe, 5-Secondary filter press, 6-Leaching liquid tank, 61-Electric heating element, 62-Power supply, 63-Mixing shaft, 64-Spiral stirring blade, 65-Rotating motor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are performed according to conventional conditions or conditions recommended by the manufacturer; where the manufacturers of instruments, equipment, reagents, or raw materials are not specified, they are all conventional products that can be purchased commercially. The following are specific embodiments in conjunction with the accompanying drawings.

[0022] like Figures 1 to 3As shown, this embodiment provides a lithium sulfate purification system, which includes a main filtration system and a secondary filtration system connected sequentially along the flow direction of the lithium sulfate purification liquid. The feed end of the main filtration system is also equipped with a lithium hydraulic filter 1, and the discharge end of the secondary filtration system is connected to a leachate tank 6. The feed end of the main filtration system is equipped with a lime feed pipe 21. The lithium hydraulic filter 1 is a plate and frame filter press, which has a high-efficiency filtration effect and stable filtration pressure, and can effectively remove solid impurities in the lithium sulfate purification liquid.

[0023] In this embodiment, the main filter system includes a main filter tank 2 and a primary filter press 3 connected in sequence. The feed end of the lime feed pipe 21 is inserted into the feed end of the main filter tank 2, and the feed end of the main filter tank 2 is also connected to the discharge end of the lithium hydraulic filter press 1 through a pipe. The discharge end of the primary filter press 3 is connected to the feed end of the secondary filter system.

[0024] In this embodiment, a stirring mechanism is installed inside the main filter tank 2. The stirring mechanism is located between the outlet end of the lime feed pipe 21 and the outlet end of the main filter tank 2. The stirring mechanism includes a filter stirring rod 22 and several stirring paddles 23 surrounding the side wall of the filter stirring rod 22. The filter stirring rod 22 extends vertically through the bottom of the main filter tank 2, and a drive motor 24 is installed at the end of the filter stirring rod 22 that extends through the main filter tank 2. The end of the filter stirring rod 22 is screwed or welded to the through shaft of the drive motor 24. The stirring mechanism can be used to promote the mixing reaction of lithium sulfate purification solution and lime, thereby improving the purification effect.

[0025] In this embodiment, the secondary filtration system includes a secondary filtration tank 4 and a secondary filtration filter press 5 connected in sequence. The feed end of the secondary filtration tank 4 is connected to the discharge end of the primary filtration filter press 3, and the discharge end of the secondary filtration filter press 5 is connected to the feed end of the leachate tank 6.

[0026] In this embodiment, a drain pipe 41 is installed at the bottom of the secondary filter tank 4. The drain pipe 41 connected to the bottom of the secondary filter tank 4 can be used to discharge impurities and precipitates generated during the purification process.

[0027] In this embodiment, an electric heating mechanism is provided on the side wall of the leaching tank 6. The electric heating mechanism includes an electric heating tube 61 and a power supply 62. The electric heating tube 61 is embedded in the side wall of the leaching tank 6 and is electrically connected to the power supply 62. Those skilled in the art can directly use industrially common electric heating tubes and small power supplies as the electric heating tube 61 and power supply 62 in this embodiment. The electric heating mechanism in the leaching tank 6 can be used to heat and stir the purified lithium sulfate solution to promote its reaction and dissolution with other substances. A mixing mechanism is also provided in the inner cavity of the leaching tank 6. The mixing mechanism includes a mixing shaft 63 and a spiral stirring blade 64 wrapped around the side wall of the mixing shaft 63. The mixing shaft 63 is vertically inserted through the top of the leaching tank 6, and a rotating motor 65 is provided at the end of the mixing shaft 63 that extends out of the top of the leaching tank 6. The end of the mixing shaft 63 is screwed to the through shaft of the rotating motor 65.

[0028] After treatment by the lithium sulfate purification system in this embodiment, the silicon content in the purified liquid can be controlled at around 0.0030 g / L, which can effectively reduce the silicon content in the raw material before purification and improve the purity and quality of lithium sulfate and downstream products.

[0029] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A lithium sulfate purification system, characterized in that, Along the flow direction of the lithium sulfate purification liquid, there are a main filtration system and a secondary filtration system connected in sequence. The feed end of the main filtration system is also equipped with a lithium hydraulic filter (1), and the discharge end of the secondary filtration system is also connected to a leachate tank (6). The feed end of the main filtration system is equipped with a lime feed pipe (21).

2. The lithium sulfate purification system according to claim 1, characterized in that, The main filter system includes a main filter tank (2) and a primary filter press (3) connected in sequence. The feed end of the lime feed pipe (21) is inserted into the feed end of the main filter tank (2), and the feed end of the main filter tank (2) is also connected to the discharge end of the lithium hydraulic filter (1) through a pipe. The discharge end of the primary filter press (3) is connected to the feed end of the secondary filter system.

3. The lithium sulfate purification system according to claim 2, characterized in that, The inner cavity of the main filter tank (2) is equipped with a stirring mechanism, which is located between the discharge end of the lime feed pipe (21) and the discharge end of the main filter tank (2).

4. The lithium sulfate purification system according to claim 3, characterized in that, The stirring mechanism includes a filter-penetrating stirring rod (22) and a plurality of stirring paddles (23) surrounding the side wall of the filter-penetrating stirring rod (22). The filter-penetrating stirring rod (22) extends vertically through the bottom of the main filter-penetrating tank (2). A drive motor (24) is provided at the end of the filter-penetrating stirring rod (22) that extends through the main filter-penetrating tank (2). The end of the filter-penetrating stirring rod (22) is detachably connected to the through shaft of the drive motor (24).

5. The lithium sulfate purification system according to claim 2, characterized in that, The secondary filtration system includes a secondary filtration tank (4) and a secondary filtration filter press (5) connected in sequence. The feed end of the secondary filtration tank (4) is connected to the discharge end of the primary filtration filter press (3), and the discharge end of the secondary filtration filter press (5) is connected to the feed end of the leachate tank (6).

6. The lithium sulfate purification system according to claim 5, characterized in that, A drain pipe (41) is installed at the bottom of the secondary filter tank (4).

7. The lithium sulfate purification system according to claim 1, characterized in that, The side wall of the leaching tank (6) is provided with an electric heating mechanism, which includes an electric heating tube (61) and a power supply (62). The electric heating tube (61) is embedded in the side wall of the leaching tank (6) and is electrically connected to the power supply (62).

8. The lithium sulfate purification system according to claim 7, characterized in that, The leaching tank (6) is equipped with a mixing mechanism in its inner cavity. The mixing mechanism includes a mixing shaft (63) and a spiral stirring blade (64) that is wound around the side wall of the mixing shaft (63). The mixing shaft (63) is vertically inserted through the top of the leaching tank (6). A rotating motor (65) is provided at the end of the mixing shaft (63) that extends out of the top of the leaching tank (6). The end of the mixing shaft (63) is detachably connected to the through shaft of the rotating motor (65).

Images