System for reducing water-soluble impurities in lithium carbonate and reducing water pollution

Abstract

The utility model discloses a system for reducing water-soluble impurities in lithium carbonate and reducing water pollution, which comprises a device for preparing a sodium carbonate solution, a plate-and-frame filter press, a lithium precipitation reaction kettle, a lithium precipitation transfer tank, a separator, a slurrying tank, a stirring and washing tank and an evaporation and concentration device which are sequentially connected, the lithium precipitation reaction kettle is communicated with the evaporation and concentration device, and the lithium precipitation transfer tank is communicated with the separator. The evaporation and concentration device is used for producing pure water, the evaporation and concentration device is further connected with a condensation water tank, water-soluble impurities in lithium carbonate can be efficiently removed through multi-stage purification, meanwhile, the used pure water is subjected to solid-liquid separation for many times and reused, internal circulation of the pure water in the production process can be achieved, a large amount of pure water does not need to be consumed, and the production cost is reduced. A large amount of pure water is prevented from being polluted, the problems of production cost and environmental pollution can be reduced, the purpose of reducing water-soluble impurities is achieved, and remarkable environment-friendly and economic benefits are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium carbonate purification, in particular to a system for reducing water-soluble impurities in lithium carbonate and reducing water pollution. Background Art

[0002] With the development of new energy technology, lithium-ion batteries have also seen rapid development. Lithium carbonate, one of the main raw materials for lithium battery positive electrode materials, has also received close attention from companies and scholars inside and outside the industry. Improving the purity of raw materials and reducing impurities in battery-grade lithium carbonate are current technical difficulties and key points. In the prior art, repeated stirring and washing methods are usually used to improve the purity of lithium carbonate. The repeated washing method consumes a large amount of pure water, which will cause a large amount of pure water to be contaminated. The increase in material consumption will lead to an increase in cost, which is not conducive to industrial production. Therefore, a system for reducing water-soluble impurities in lithium carbonate and reducing water pollution is proposed. Utility Model Content

[0003] The purpose of the utility model is to solve any one of the problems in the above-mentioned technologies, thereby proposing a system for reducing water-soluble impurities in lithium carbonate and reducing water pollution, comprising a device for preparing sodium carbonate solution, a plate and frame filter press, a lithium precipitation reactor, a lithium precipitation transfer tank, a separator, a slurry tank, a stirring and washing tank and an evaporation and concentration device, wherein the above-mentioned devices are connected in sequence, the lithium precipitation reactor is interconnected with the evaporation and concentration device, the evaporation and concentration device is used to produce pure water, and the evaporation and concentration device is also connected with a condensation water tank.

[0004] Furthermore, the separator includes a primary separator, a secondary separator and a tertiary separator, the slurrying tank includes a primary slurrying tank and a secondary slurrying tank, the stirring and washing tank includes a primary stirring and washing tank and a secondary stirring and washing tank, the condensation water tank is used to store pure water and is connected to the secondary slurrying tank, the secondary separator and the tertiary separator are both connected to a tertiary separation liquid tank, and the tertiary separation liquid tank is connected to a plate and frame filter press.

[0005] Furthermore, the primary separator, the primary pulping tank, the primary stirring and washing tank, the secondary separator, the secondary pulping tank, the secondary stirring and washing tank and the tertiary separator are connected in sequence.

[0006] Furthermore, the tertiary separation water separated by the tertiary separator will be injected into the primary slurry tank.

[0007] Furthermore, the separator and plate-and-frame filter press are devices for solid-liquid separation.

[0008] Furthermore, the slurry tank and the stirring and washing tank are devices for mixing solids and liquids.

[0009] Beneficial effects: By setting up a multi-stage purification, water-soluble impurities in lithium carbonate can be efficiently removed. At the same time, by separating the used pure water into solid and liquid for multiple times and reusing them, the pure water can be internally circulated in the production process without consuming a large amount of pure water, thus avoiding the pollution of a large amount of pure water. The production cost and environmental pollution problems can be reduced, and the purpose of reducing water-soluble impurities is achieved, which has significant environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is the overall flow chart of the utility model; DETAILED DESCRIPTION

[0011] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0012] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention.

[0013] Below, the system for reducing water-soluble impurities in lithium carbonate and reducing water pollution according to an embodiment of the utility model is described with reference to the accompanying drawings, such as Figure 1 As shown, the system for reducing water-soluble impurities in lithium carbonate and reducing water pollution includes a device for preparing sodium carbonate solution, a plate and frame filter press, a lithium precipitation reactor, a lithium precipitation transfer tank, a separator, a slurry tank, a stirring and washing tank and an evaporation and concentration device, the above devices are connected in sequence, the lithium precipitation reactor is connected to the evaporation and concentration device, the evaporation and concentration device is used to produce pure water, and the evaporation and concentration device is also connected to a condensation water tank.

[0014] In a specific embodiment: by adding an evaporation concentration device, production only needs to add pure water at the initial startup stage, and the dependence on pure water can be reduced by 90% in normal production thereafter. Small particles of lithium carbonate in the separated water can also be collected, and the lithium carbonate extracted from the separated water accounts for about 10% of the total output.

[0015] Preferably, the separator includes a primary separator, a secondary separator and a tertiary separator, the slurrying tank includes a primary slurrying tank and a secondary slurrying tank, the stirring and washing tank includes a primary stirring and washing tank and a secondary stirring and washing tank, the condensation water tank is used to store pure water and is connected to the secondary slurrying tank, the secondary separator and the tertiary separator are both connected to a tertiary separation liquid tank, and the tertiary separation liquid tank is connected to the plate and frame filter press.

[0016] Preferably, the primary separator, the primary pulping tank, the primary stirring and washing tank, the secondary separator, the secondary pulping tank, the secondary stirring and washing tank and the tertiary separator are connected in sequence.

[0017] Preferably, the tertiary separation water separated by the tertiary separator will be injected into the primary slurry tank.

[0018] In a specific embodiment, the material coming out of the lithium precipitation reactor contains a large amount of water-soluble impurities, such as EDTA, SO4 2- ,CO3 2- , Cl - , OH - , K + However, it is very wasteful to use pure water for each washing. Therefore, adding the separation liquid from the separator three times during one washing can also effectively reduce the content of water-soluble impurities in the material, and achieve internal circulation of pure water in the workshop process and factory area, thereby reducing production costs and environmental pollution, and achieving the purpose of reducing water-soluble impurities.

[0019] Preferably, the separator and plate and frame filter press are devices for solid-liquid separation. The plate and frame filter press is a commonly used solid-liquid separation equipment. It forms a filter chamber by stacking plate and frame components, and uses pressure difference to drive the liquid through the filter cloth, thereby achieving the purpose of solid-liquid separation.

[0020] Preferably, the slurry tank and the stirring and washing tank are devices used to mix solids and liquids. The slurry tank is a device used to mix solid matter with liquid. Its principle is to stir, grind and disperse the solid matter and liquid through mechanical or physical force so that the solid matter is evenly dispersed in the liquid.

[0021] Working principle: The material starts with the preparation of sodium carbonate solution, and then is processed by a plate and frame filter press and transported to the lithium precipitation reactor. The material after the treatment of the lithium precipitation reactor is a mixture of supernatant (liquid containing various impurities) and lithium carbonate precipitation, which is then transported to the lithium precipitation transfer tank for storage. Part of the supernatant will be transported to the evaporation concentration device to prepare pure water. When the primary separator needs to be replenished, the material stored in the lithium precipitation transfer tank is transported to the primary separator for solid-liquid separation. The separated liquid is transported to the evaporation concentration process to make pure water, and the separated solid is transported to the primary slurry tank. At the same time, the water separated in the tertiary separator is added to the primary slurry tank for slurrying. After the slurrying, the material is transported to a larger volume stirring and washing tank for stirring and washing. After the stirring and washing, it is transported to the secondary separator for solid-liquid separation. The liquid flows to the plate and frame filter press through the tertiary separation liquid tank for Solid-liquid separation, the separated solid is small particles of lithium carbonate, and the separated liquid is injected into the initial device for preparing sodium carbonate solution. The solid separated by the secondary separator is put into the secondary slurry tank, and then pure water is injected into the secondary slurry tank. After washing, it is transported to the secondary stirring and washing tank for stirring and washing, so that the water-soluble impurities are in more sufficient contact with the pure water, and finally transported to the tertiary separator. The solid separated by the tertiary separator is the product, which is battery-grade lithium carbonate. The liquid separated by the tertiary separator is processed by a plate and frame filter press and then transported to the primary slurry tank; the lithium precipitation reactor will also regularly discharge the supernatant into the evaporation and concentration device, which evaporates and removes the water in the solution, and then cools it, stores it in the condensation water tank, and then passes through a precision filter to remove impurities and use it as pure water for recycling, which can reduce production costs and environmental pollution problems, and has significant environmental and economic benefits.

Claims

1. A system for reducing water-soluble impurities in lithium carbonate and reducing water pollution, characterized in that: The invention comprises a device for preparing sodium carbonate solution, a plate and frame filter press, a lithium precipitation reaction kettle, a lithium precipitation transfer tank, a separator, a slurry tank, a stirring and washing tank and an evaporation and concentration device, wherein the above devices are connected in sequence, the lithium precipitation reaction kettle is interconnected with the evaporation and concentration device, the evaporation and concentration device is used for producing pure water, and the evaporation and concentration device is also connected with a condensation water tank.

2. The system for reducing water-soluble impurities in lithium carbonate and reducing water pollution as claimed in claim 1, characterized in that, The separator includes a primary separator, a secondary separator and a tertiary separator, the slurry tank includes a primary slurry tank and a secondary slurry tank, the stirring and washing tank includes a primary stirring and washing tank and a secondary stirring and washing tank, the condensation water tank is used to store pure water and is connected to the secondary slurry tank, the secondary separator and the tertiary separator are both connected to a tertiary separation liquid tank, and the tertiary separation liquid tank is connected to a plate and frame filter press.

3. The system for reducing water-soluble impurities in lithium carbonate and reducing water pollution as claimed in claim 2, characterized in that, The primary separator, the primary pulping tank, the primary stirring and washing tank, the secondary separator, the secondary pulping tank, the secondary stirring and washing tank and the tertiary separator are connected in sequence.

4. The system for reducing water-soluble impurities in lithium carbonate and reducing water pollution as claimed in claim 2, characterized in that, The tertiary separation water separated by the tertiary separator will be injected into the primary slurry tank.

5. The system for reducing water-soluble impurities in lithium carbonate and reducing water pollution as claimed in claim 1, characterized in that, The separator and plate-and-frame filter press are devices used for solid-liquid separation.

6. The system for reducing water-soluble impurities in lithium carbonate and reducing water pollution as claimed in claim 1, characterized in that, The slurry tank and the stirring and washing tank are devices used to mix solids and liquids.

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