Continuous crystallizer for lithium hexafluorophosphate

Abstract

A continuous crystallizer for lithium hexafluorophosphate comprises a crystallizing tank, a spiral pipe is arranged in the crystallizing tank, a material inlet is formed in the top of the crystallizing tank, a material outlet is formed in the bottom of the crystallizing tank, and the two ends of the spiral pipe are in butt joint with the material inlet and the material outlet respectively; in conclusion, the crystallizing tank is provided with three temperature control areas, namely the pre-cooling cavity, the cooling cavity and the crystallizing cavity, and materials sequentially pass through the three temperature control areas of the crystallizing tank along the spiral pipe, so that gradient cooling crystallization is realized, crystallized particles grow uniformly, and the crystallization time is short.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium hexafluorophosphate production equipment, and in particular relates to a continuous crystallizer for lithium hexafluorophosphate. Background Art

[0002] Lithium-ion batteries are composed of four major materials, namely, positive electrode, negative electrode, electrolyte, and diaphragm. The electrolyte cost accounts for about 5%-10%, and is one of the main key raw materials for lithium-ion batteries. Lithium battery electrolytes are synthesized from lithium salts, solvents, etc. Lithium hexafluorophosphate (LiPF6) is the main raw material for manufacturing lithium-ion battery electrolytes. Due to its good ionic conductivity and electrochemical stability, the most widely used method for industrial production of lithium hexafluorophosphate is the hydrofluoric acid solvent method, that is, phosphorus pentafluoride and lithium fluoride dissolved in anhydrous hydrofluoric acid liquid react to obtain a lithium hexafluorophosphate solution, and the lithium hexafluorophosphate is then crystallized from the hydrofluoric acid solution, and the finished product is obtained by filtration and drying; when preparing lithium hexafluorophosphate using the hydrofluoric acid solvent method, the crystallization process is a key step in controlling product quality, and in the existing lithium hexafluorophosphate preparation process, the crystal particles grow unevenly and the crystallization time is long. Utility Model Content

[0003] The utility model aims to provide a continuous crystallizer for lithium hexafluorophosphate, which solves the technical problems of uneven growth of crystal particles and long crystallization time in the existing lithium hexafluorophosphate crystallization device.

[0004] In order to solve the above technical problems, the utility model adopts the following technical solutions: a continuous crystallizer for lithium hexafluorophosphate, comprising a crystallization tank, a spiral tube is arranged in the crystallization tank, a material inlet is arranged at the top of the crystallization tank, a material outlet is arranged at the bottom of the crystallization tank, and both ends of the spiral tube are respectively connected to the material inlet and the material outlet;

[0005] The inner cavity of the crystallization tank is divided into a precooling cavity, a cooling cavity and a crystallization cavity, which are arranged in sequence from top to bottom; a precooling refrigerant inlet is connected to the lower part of the precooling cavity of the crystallization tank, and a precooling refrigerant outlet is connected to the upper part of the precooling cavity of the crystallization tank; a cooling refrigerant inlet is connected to the lower part of the cooling cavity of the crystallization tank, and a cooling refrigerant outlet is connected to the upper part of the cooling cavity of the crystallization tank; a crystallization refrigerant inlet is connected to the lower part of the crystallization cavity of the crystallization tank, and a crystallization refrigerant outlet is connected to the upper part of the crystallization cavity of the crystallization tank.

[0006] Compared with the prior art, the beneficial effects of the utility model are as follows: the crystallization tank of the utility model is provided with three temperature control areas, namely a pre-cooling chamber, a cooling chamber and a crystallization chamber. The material passes through the three temperature control areas of the crystallization tank in sequence along the spiral tube to achieve gradient cooling crystallization, the crystal particles grow evenly, and the crystallization time is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0008] Figure 1 The utility model is a structural schematic diagram of a continuous crystallizer for lithium hexafluorophosphate. DETAILED DESCRIPTION

[0009] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0010] The present invention is further described in detail below in conjunction with the embodiments.

[0011] like Figure 1 As shown, a specific embodiment of a continuous crystallizer for lithium hexafluorophosphate provided by the utility model:

[0012] A continuous crystallizer for lithium hexafluorophosphate comprises a crystallizer 1, a spiral tube 2 is arranged in the crystallizer 1, a material inlet N1 is arranged at the top of the crystallizer 1, a material outlet N2 is arranged at the bottom of the crystallizer 1, and two ends of the spiral tube 2 are respectively connected to the material inlet N1 and the material outlet N2;

[0013] The inner cavity of the crystallizer 1 is divided into a precooling cavity 3, a cooling cavity 4 and a crystallization cavity 5, which are arranged in sequence from top to bottom; a precooling refrigerant inlet N3 is connected to the lower portion of the precooling cavity 3 of the crystallizer 1, and a precooling refrigerant outlet N4 is connected to the upper portion of the precooling cavity 3 of the crystallizer 1; a cooling refrigerant inlet N5 is connected to the lower portion of the cooling cavity 4 of the crystallizer 1, and a cooling refrigerant outlet N6 is connected to the upper portion of the cooling cavity 4 of the crystallizer 1; a crystallization refrigerant inlet N7 is connected to the lower portion of the crystallization cavity 5 of the crystallizer 1, and a crystallization refrigerant outlet N8 is connected to the upper portion of the crystallization cavity 5 of the crystallizer 1.

[0014] When the continuous crystallizer of the present embodiment is used for crystallization, the material enters from the material inlet N1, and continuously enters the crystallization tank 1 from top to bottom through the spiral tube 2. First, the material temperature is controlled to the set temperature in the precooling chamber 3, and then enters the cooling chamber 4 for further cooling. When the material exits the cooling chamber 4, the material temperature reaches the crystallization temperature. After entering the crystallization chamber 5, the material flows and crystallizes in the spiral tube 2. The crystallization process ends when the material reaches the material outlet N2, and then the solid-liquid separation process is entered.

[0015] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0016] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A continuous crystallizer for lithium hexafluorophosphate, characterized in that: The invention comprises a crystallization tank, wherein a spiral tube is arranged in the crystallization tank, a material inlet is arranged at the top of the crystallization tank, a material outlet is arranged at the bottom of the crystallization tank, and two ends of the spiral tube are respectively connected with the material inlet and the material outlet; The inner cavity of the crystallization tank is divided into a precooling cavity, a cooling cavity and a crystallization cavity, which are arranged in sequence from top to bottom; a precooling refrigerant inlet is connected to the lower part of the precooling cavity of the crystallization tank, and a precooling refrigerant outlet is connected to the upper part of the precooling cavity of the crystallization tank; a cooling refrigerant inlet is connected to the lower part of the cooling cavity of the crystallization tank, and a cooling refrigerant outlet is connected to the upper part of the cooling cavity of the crystallization tank; a crystallization refrigerant inlet is connected to the lower part of the crystallization cavity of the crystallization tank, and a crystallization refrigerant outlet is connected to the upper part of the crystallization cavity of the crystallization tank.

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