System for continuously leaching lithium sulfate by spodumene method

Abstract

The invention discloses a spodumene method lithium sulfate continuous leaching system which is characterized in that spodumene acidified clinker is fed into a first-stage first leaching cavity through a feeding mechanism, water is introduced into the first leaching cavity, and the spodumene acidified clinker contains a certain amount of sulfuric acid, so that leaching liquid in the first leaching cavity is acidic; the spodumene acidified clinker is leached out of lithium sulfate under the acidic condition in the first leaching cavity, then a calcium carbonate solution is introduced into the second leaching cavity, calcium carbonate can neutralize acidity, and therefore when the leachate overflows and flows step by step in the second leaching cavity, the acidity of the leachate is slowly neutralized by the calcium carbonate. According to the method, leaching is conducted under the acidic and slow neutralization condition, so that the lithium content in the leached tailings is reduced, and the leaching rate is high.

Description

Technical Field

[0001] The invention relates to the technical field of lithium sulfate production, in particular to a spodumene-based lithium sulfate continuous leaching system. Background Art

[0002] The existing large-scale spodumene method for producing lithium sulfate mainly uses intermittent manual leaching operations, which has low efficiency. Therefore, some companies have gradually tried continuous leaching. The existing continuous leaching system mainly connects multiple leaching chambers in series to increase the solid-liquid contact time and enhance the stirring efficiency, thereby achieving continuous leaching. However, it is generally leached under neutral or over-alkaline conditions, which will result in a large amount of lithium in the leaching tailings, resulting in a low leaching rate. Summary of the invention

[0003] The present application provides a spodumene-based lithium sulfate continuous leaching system, which performs leaching under acidic and slowly neutralized conditions to reduce the lithium content in the leached tailings, thereby achieving a higher leaching rate.

[0004] The spodumene-based lithium sulfate continuous leaching system provided in this application includes: The first leaching unit comprises a plurality of first leaching chambers connected in series, wherein the liquid in each first leaching chamber can overflow into the first leaching chamber of the next first leaching chamber; The second leaching unit comprises a plurality of second leaching chambers connected in series, wherein the liquid in each second leaching chamber can overflow into the second leaching chamber of the next stage, and the liquid in the first leaching chamber of the last stage can overflow into the second leaching chamber of the first stage; A feeding mechanism, used for feeding the spodumene acidified clinker into the first leaching chamber of the first stage; A first main pipe is used to connect to a water source, and the first main pipe delivers water to each first leaching chamber through the first branch pipe; A second main pipe is used to connect the calcium carbonate solution, and the second main pipe delivers the calcium carbonate solution into each second leaching chamber through the second branch pipe; The output pipeline is used to transport the leaching slurry in the second leaching chamber of the last stage to the outside, and a delivery pump is arranged on the output pipeline.

[0005] Preferably, a first flow meter and a first regulating valve are provided on the first branch pipe connected to the first leaching chamber of the first stage, the feeding mechanism includes a weighing sensor, the weighing sensor is used to weigh the material transported by the feeding mechanism, and the first regulating valve adjusts the opening according to the detection data of the weighing sensor.

[0006] Preferably, a second flow meter and a second regulating valve are provided on the first branch pipe connected to the first leaching chamber of the last stage, and a density meter is provided on the second leaching chamber of the first stage. The density meter is used to detect the density of the solution in the second leaching chamber of the first stage, and the second regulating valve adjusts the opening according to the detection data of the density meter.

[0007] Preferably, each second branch pipe is provided with a third flow meter and a third regulating valve, and each second leaching chamber is provided with a pH meter, which is used to detect the pH value of the solution in the second leaching chamber, and each third regulating valve adjusts its opening according to the detection data of the pH meter on the second leaching chamber to which the second branch pipe is connected.

[0008] Preferably, each first leaching chamber and each second leaching chamber is provided with a liquid level meter.

[0009] Preferably, a fourth flow meter and a fourth regulating valve are provided on the output pipeline, and the fourth regulating valve adjusts the opening of the fourth regulating valve according to the detection data of the liquid level meter on the second leaching chamber of the last stage.

[0010] Preferably, the first leaching chamber of each stage is connected to the first leaching chamber of the next stage, the second leaching chamber of each stage is connected to the second leaching chamber of the next stage, and the first leaching chamber of the last stage is connected to the second leaching chamber of the first stage through an overflow pipe, the inlet end of each overflow pipe is close to the bottom of the first leaching chamber or the second leaching chamber, and the outlet end of each overflow pipe is close to the upper part of the side wall of the first leaching chamber or the second leaching chamber.

[0011] Preferably, a first filter screen cover is sleeved on the inlet end of the overflow pipe in the first leaching chamber of the first stage, a second filter screen cover is sleeved on the outer side of the first filter screen cover, and the mesh of the first filter screen cover is smaller than that of the second filter screen cover.

[0012] Preferably, a stirring shaft is provided in the first leaching chamber of the first stage, the stirring shaft is driven to rotate by a first motor, a stirring blade is provided on the stirring shaft, the first filter screen cover is fixedly connected to the overflow pipe, the second filter screen cover is rotatably connected to the overflow pipe, and a second motor for driving the second filter screen cover to rotate is provided on the outside of the bottom wall of the first leaching chamber of the first stage, the rotation direction of the stirring shaft is opposite to the rotation direction of the second filter screen cover, the bottom inner surface of the second filter screen cover is covered with convex columns, a convex block is fixedly provided on the outer surface of the first filter screen cover, and a flexible column is provided on the inner surface of the second filter screen cover, and when the second filter screen cover rotates, the flexible column can continuously hit the convex block.

[0013] Preferably, acid-resistant tiles are attached to the inner wall of each first leaching chamber and the second leaching chamber.

[0014] One or more technical solutions provided in this application have at least the following technical effects or advantages: When the continuous leaching system of the present application is working, the feeding mechanism feeds the spodumene acidified clinker into the first-stage first leaching chamber, and water is connected to the first leaching chamber. Since the spodumene acidified clinker contains a certain amount of sulfuric acid, the leaching solution in the first leaching chamber is acidic, so that the spodumene acidified clinker leaches lithium sulfate under the acidic conditions in the first leaching chamber, and then the second leaching chamber is connected to a calcium carbonate solution, and the calcium carbonate can neutralize the acidity, so that when the leaching solution overflows step by step in the second leaching chamber, the acidity of the leaching solution is slowly neutralized by the calcium carbonate. In this way, the spodumene acidified clinker is leached under acidic and slowly neutralized conditions, so that the lithium content in the leaching tailings is reduced, thereby making the leaching rate higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a partial schematic diagram of the first leaching chamber of the first stage; DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0018] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products, or devices.

[0019] like Figure 1 , Figure 2 As shown, the spodumene-based lithium sulfate continuous leaching system of this embodiment includes a first leaching unit, a second leaching unit, a feeding mechanism, a first main pipe 30 , a second main pipe 40 and an output pipeline 50 .

[0020] The first leaching unit includes a plurality of first leaching chambers 10 connected in series in sequence. The liquid in each first leaching chamber 10 can overflow into the first leaching chamber 10 of the next stage. That is to say, each first leaching chamber 10 is connected to the first leaching chamber 10 of the next stage through an overflow pipe 70.

[0021] The second leaching unit includes a plurality of second leaching chambers 20 connected in series in sequence. The liquid in each second leaching chamber 20 can overflow into the second leaching chamber 20 of the next stage. That is to say, each second leaching chamber 20 is connected to the second leaching chamber 20 of the next stage through an overflow pipe 70.

[0022] The liquid in the last stage first leaching chamber 10 can overflow into the first stage second leaching chamber 20 , that is, the last stage first leaching chamber 10 is connected to the first stage second leaching chamber 20 through the overflow pipe 70 .

[0023] The feeding mechanism is used to feed the spodumene acidified clinker into the first leaching chamber 10 of the first stage. The feeding mechanism is a weighing screw conveyor 100. The screw conveyor is provided with a conveying motor and a weighing sensor. The conveying motor provides power for the spiral blades, and the weighing sensor is used to weigh the material conveyed by the screw conveyor.

[0024] The first main pipe 30 is used to connect to a water source, and the first main pipe 30 delivers water to each first leaching chamber 10 through the first branch pipes 31 .

[0025] The second main pipe 40 is used to connect the calcium carbonate solution, which is a pre-configured calcium carbonate standard solution. The second main pipe 40 delivers the calcium carbonate solution into each second leaching chamber 20 through the second branch pipe 41.

[0026] The output pipeline 50 is used to transport the leached slurry in the second leaching chamber 20 of the last stage to the outside. The output pipeline 50 is provided with a delivery pump 51. In this way, when the continuous leaching system is working, the weighing screw conveyor 100 delivers the spodumene acidified clinker to the first stage first leaching chamber 10. The first leaching chamber 10 is connected to water through the first branch pipe 31. Since the spodumene acidified clinker contains a certain amount of sulfuric acid, the leachate in the first leaching chamber 10 is acidic, so that the spodumene acidified clinker leaches lithium sulfate under the acidic conditions in the first leaching chamber 10, and then the second leaching chamber 20 is connected to the calcium carbonate solution. Calcium carbonate can neutralize the acidity, so that when the leachate overflows step by step in the second leaching chamber 20, the acidity of the leachate is slowly neutralized by calcium carbonate.

[0027] A first flow meter 32 and a first regulating valve 33 are provided on the first branch pipe 31 connected to the first leaching chamber 10 of the first stage. The first regulating valve 33 adjusts the opening according to the detection data of the weighing sensor, so that the flow of the first branch pipe 31 connected to the first leaching chamber 10 of the first stage matches the material conveying amount of the weighing screw conveyor 100, and the first flow meter 32 can detect the flow of the first branch pipe 31 to determine whether the opening adjustment of the first regulating valve 33 is in place.

[0028] A second flowmeter 34 and a second regulating valve 35 are provided on the first branch pipe 31 connected to the first leaching chamber 10 of the last stage, and a densitometer 21 is provided on the second leaching chamber 20 of the first stage. The densitometer 21 is used to detect the density of the solution in the second leaching chamber 20 of the first stage. The second regulating valve 35 adjusts the opening according to the detection data of the densitometer 21, so that the water inflow of the first leaching chamber 10 of the last stage can be adjusted according to the density of the solution in the second leaching chamber 20 of the first stage, so that the density of the solution in the second leaching chamber 20 of the first stage reaches a preset value, and the second flowmeter 34 can detect the flow of the first branch pipe 31 to determine whether the opening adjustment of the second regulating valve 35 is in place.

[0029] A third flow meter 42 and a third regulating valve 43 are provided on each second branch pipe 41, and a pH meter 22 is provided on each second leaching chamber 20. The pH meter 22 is used to detect the pH value of the solution in the second leaching chamber 20. Each third regulating valve 43 adjusts its opening according to the detection data of the pH meter 22 on the second leaching chamber 20 connected to the second branch pipe 41, so that the amount of calcium carbonate solution entering each second leaching chamber 20 can be adjusted according to the pH value of the solution in each second leaching chamber 20, so that the pH value of the solution in each level of the second leaching chamber 20 is lower than the pH value of the solution in the second leaching chamber 20 of the previous level, so as to achieve the effect of slowly neutralizing the acidity of the leachate.

[0030] A liquid level meter 60 is disposed on each first leaching chamber 10 and each second leaching chamber 20 , and the liquid level meter 60 can detect the liquid level in the first leaching chamber 10 and the second leaching chamber 20 .

[0031] The output pipeline 50 is provided with a fourth flow meter 52 and a fourth regulating valve 53. The fourth regulating valve 53 adjusts the opening of the fourth regulating valve 53 according to the detection data of the liquid level meter 60 on the second leaching chamber 20 of the last stage, so that the opening of the fourth regulating valve 53 can be adjusted according to the liquid level in the second leaching chamber 20 of the last stage, so that when the liquid level in the second leaching chamber 20 of the last stage is high, the output flow of the output pipeline 50 can be large, and when the liquid level in the second leaching chamber 20 of the last stage is low, the output flow of the output pipeline 50 can be small, and the fourth flow meter 52 can detect the flow of the output pipeline to determine whether the opening adjustment of the fourth regulating valve 53 is implemented in place.

[0032] The first flow meter 32, the first regulating valve 33, the second flow meter 34, the second regulating valve 35, the third flow meter 42, the third regulating valve 43, the fourth flow meter 52, the fourth regulating valve 53, the density meter 21, the pH meter 22, the liquid level meter 60, and the conveying motor and the weighing sensor on the weighing screw conveyor 100 are all communicatively connected to the control system, and parameter setting and automatic adjustment are performed through the control system.

[0033] The inlet end of each overflow pipe 70 is close to the bottom of the first leaching chamber 10 or the second leaching chamber 20, and the outlet end of each overflow pipe 70 is close to the upper position of the side wall of the first leaching chamber 10 or the second leaching chamber 20. Each overflow pipe 70 penetrates the side wall of the first leaching chamber 10 or the second leaching chamber 20 and extends into the first leaching chamber 10 or the second leaching chamber 20, so that the overflow pipe 70 is built-in to reduce the space occupied by the entire continuous leaching system.

[0034] A first filter screen cover 71 is mounted on the inlet end of the overflow pipe 70 in the first leaching chamber 10 of the first stage, and a second filter screen cover 72 is mounted outside the first filter screen cover 71. The mesh of the first filter screen cover 71 is smaller than that of the second filter screen cover 72. In this way, the solution in the first leaching chamber 10 of the first stage overflows into the first leaching chamber 10 of the next stage after double-layer filtration, and the filtering effect is better.

[0035] A stirring shaft 200 is provided in the first leaching chamber 10 of the first stage, and the stirring shaft 200 is driven to rotate by a first motor. The first motor is located above the first leaching chamber 10 of the first stage, and a stirring blade is provided on the stirring shaft 200. A first filter screen cover 71 is fixedly connected to the overflow pipe 70, and the first filter screen cover 71 completely covers the inlet end of the overflow pipe 70. The second filter screen cover 72 is rotatably connected to the overflow pipe 70, that is, a rotating seat 701 is rotatably provided on the outer peripheral wall of the overflow pipe 70, and the second filter screen cover 72 is connected to the rotating seat 701. The second filter screen cover 72 is arranged on the bottom wall 11 of the first leaching chamber 10 of the first stage so that the second filter screen cover 72 can rotate relative to the overflow pipe 70, and the second filter screen cover 72 completely covers the first filter screen cover 71. A second motor 12 for driving the second filter screen cover 72 to rotate is arranged outside the bottom wall 11 of the first leaching chamber 10 of the first stage. The driving shaft of the second motor 12 passes through the bottom wall 11 of the first leaching chamber 10 of the first stage and is connected to the second filter screen cover 72. The driving shaft of the second motor 12 is arranged coaxially with the overflow pipe 70. The rotation direction of the stirring shaft 200 is opposite to the rotation direction of the second filter screen cover 72. When the stirring shaft 200 and the second filter screen cover 72 are both rotating, the stirred fluid in the first stage first leaching chamber 10 can easily wash off the particles blocked on the second filter screen cover 72 to avoid clogging of the second filter screen cover 72. The bottom inner surface of the second filter screen cover 72 is covered with protruding columns 721. In this way, when the second filter screen cover 72 rotates, the protruding columns 721 can break up the solid agglomerated materials between the second filter screen cover 72 and the first filter screen cover 71, so that the solid agglomerated materials are retained between the second filter screen cover 72 and the first filter screen cover 71. A protrusion 711 is fixedly provided on the outer surface of the filter screen cover 71, and the protrusion 711 is made of a hard material. A flexible column 722 is provided on the inner surface of the second filter screen cover 72, and the flexible column 722 is made of a flexible material. When the second filter screen cover 72 rotates, the flexible column 722 can continuously hit the protrusion 711. When the flexible column 722 hits the protrusion 711, the first filter screen cover 71 can be vibrated, thereby shaking off the particles blocked on the first filter screen cover 71, so as to avoid the particles blocking the first filter screen cover 71 and making the liquid unable to flow out through the overflow pipe 70.

[0036] Acid-resistant tiles are attached to the inner walls of each of the first leaching chamber 10 and the second leaching chamber 20, so that the inner walls of the first leaching chamber 10 and the second leaching chamber 20 are not easily corroded.

[0037] Except for the first stage first leaching chamber 10, the liquids in the remaining first leaching chambers 10 and the second leaching chambers 20 are provided with stirring shafts, and stirring blades are provided on the stirring shafts. The stirring shafts are driven by the first motor to rotate, thereby driving the stirring blades to rotate to evenly stir the liquids in the remaining first leaching chambers 10 and the second leaching chambers 20.

[0038] It should be noted that the above-mentioned sequence of the embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above-mentioned specific embodiments of this specification are described. Other embodiments are within the scope of the attached claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0039] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

[0040] This specification and drawings are merely exemplary illustrations of the present application and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application and its equivalents, the present application intends to include these modifications and variations.

Claims

1. A spodumene-based lithium sulfate continuous leaching system, characterized in that: include: The first leaching unit comprises a plurality of first leaching chambers (10) connected in series, wherein the liquid in each first leaching chamber (10) can overflow into the first leaching chamber (10) of the next first leaching chamber; A second leaching unit comprises a plurality of second leaching chambers (20) connected in series, wherein the liquid in each second leaching chamber (20) can overflow into the second leaching chamber (20) of the next stage, and the liquid in the first leaching chamber (10) of the last stage can overflow into the second leaching chamber (20) of the first stage; A feeding mechanism, used for feeding the spodumene acidified clinker into the first leaching chamber (10) of the first stage; A first main pipe (30) is used to connect to a water source, and the first main pipe (30) delivers water to each first leaching chamber (10) through a first branch pipe (31); A second main pipe (40) is used to receive the calcium carbonate solution. The second main pipe (40) delivers the calcium carbonate solution to each second leaching chamber (20) through the second branch pipe (41); The output pipeline (50) is used to transport the leached slurry in the second leaching chamber (20) of the last stage to the outside, and a delivery pump (51) is provided on the output pipeline (50).

2. The spodumene-based lithium sulfate continuous leaching system according to claim 1, characterized in that: A first flow meter (32) and a first regulating valve (33) are provided on the first branch pipe (31) connected to the first leaching chamber (10) of the first stage. The feeding mechanism comprises a weighing sensor, which is used to weigh the material conveyed by the feeding mechanism. The first regulating valve (33) adjusts the opening according to the detection data of the weighing sensor.

3. The spodumene-based lithium sulfate continuous leaching system according to claim 2, characterized in that: A second flow meter (34) and a second regulating valve (35) are provided on the first branch pipe (31) connected to the first leaching chamber (10) of the last stage, and a density meter (21) is provided on the second leaching chamber (20) of the first stage. The density meter (21) is used to detect the density of the solution in the second leaching chamber (20) of the first stage, and the second regulating valve (35) adjusts the opening according to the detection data of the density meter (21).

4. The spodumene-based lithium sulfate continuous leaching system according to claim 1, characterized in that: Each second branch pipe (41) is provided with a third flow meter (42) and a third regulating valve (43), each second leaching chamber (20) is provided with a pH meter (22), the pH meter (22) being used to detect the pH value of the solution in the second leaching chamber (20), and each third regulating valve (43) adjusts its opening according to the detection data of the pH meter (22) on the second leaching chamber (20) to which the second branch pipe (41) is connected.

5. The spodumene-based lithium sulfate continuous leaching system according to claim 1, characterized in that: Each first leaching chamber (10) and each second leaching chamber (20) is provided with a liquid level meter (60).

6. The spodumene-based lithium sulfate continuous leaching system according to claim 5, characterized in that: The output pipeline (50) is provided with a fourth flow meter (52) and a fourth regulating valve (53), and the fourth regulating valve (53) adjusts the opening of the fourth regulating valve (53) according to the detection data of the liquid level meter (60) on the second leaching chamber (20) of the last stage.

7. The spodumene-based lithium sulfate continuous leaching system according to claim 1, characterized in that: The first leaching chamber (10) of each stage is connected to the first leaching chamber (10) of the next stage, the second leaching chamber (20) of each stage is connected to the second leaching chamber (20) of the next stage, and the first leaching chamber (10) of the last stage is connected to the second leaching chamber (20) of the first stage through an overflow pipe (70). The inlet end of each overflow pipe (70) is close to the bottom of the first leaching chamber (10) or the second leaching chamber (20), and the outlet end of each overflow pipe (70) is close to the upper part of the side wall of the first leaching chamber (10) or the second leaching chamber (20).

8. The spodumene-based lithium sulfate continuous leaching system according to claim 7, characterized in that: A first filter screen (71) is sleeved on the inlet end of the overflow pipe (70) in the first leaching chamber (10) of the first stage, and a second filter screen (72) is sleeved on the first filter screen (71). The mesh size of the first filter screen (71) is smaller than that of the second filter screen (72).

9. The spodumene-based lithium sulfate continuous leaching system according to claim 8, characterized in that: A stirring shaft (200) is arranged in the first leaching chamber (10) of the first stage. The stirring shaft (200) is driven to rotate by a first motor. A stirring blade is arranged on the stirring shaft (200). The first filter screen cover (71) is fixedly connected to the overflow pipe (70). The second filter screen cover (72) is rotatably connected to the overflow pipe (70). A second motor (12) for driving the second filter screen cover (72) to rotate is arranged outside the bottom wall (11) of the first leaching chamber (10) of the first stage. The rotation direction of the stirring shaft (200) is opposite to that of the second filter screen cover (72). The inner surface of the bottom of the second filter screen cover (72) is covered with convex columns (721). A convex block (711) is fixedly arranged on the outer surface of the first filter screen cover (71). A flexible column (722) is arranged on the inner surface of the second filter screen cover (72). When the second filter screen cover (72) rotates, the flexible column (722) can continuously hit the convex block (711).

10. The spodumene-based lithium sulfate continuous leaching system according to claim 1, characterized in that: Acid-resistant tiles are attached to the inner walls of each first leaching chamber (10) and the second leaching chamber (20).

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