Crystal preparation system

Abstract

The utility model discloses a crystal preparation system. The crystal preparation system comprises a preheating unit, a concentration unit, a crystallization unit, an extraction unit and a fine grain removal unit, the preheating unit is used for preheating the stock solution; the concentration unit, the crystallization unit and the extraction unit are sequentially arranged at the downstream of the preheating unit, and the concentration unit is used for concentrating the stock solution; the crystallization unit is used for carrying out crystallization treatment on the concentrated stock solution to generate crystal slurry liquid and clear liquid; the extraction unit is used for separating the crystal slurry to generate crystals; and the fine grain removal unit is used for heating the clear liquid and conveying the heated clear liquid back to the crystallization unit. In the crystallization process of the stock solution in the crystallization unit, clear liquid is treated by the fine grain removal unit, fine grains in the clear liquid are heated, dissolved and removed, and then the clear liquid is conveyed back to the crystallization unit to be subjected to crystallization treatment again. Therefore, the uniformity of particle size distribution of cobalt chloride crystals in the extraction unit can be improved, and the size of the cobalt chloride crystals is increased.

Description

Technical Field

[0001] The present application belongs to the technical field of cobalt chloride production and preparation, and specifically relates to a crystal preparation system. Background Art

[0002] Cobalt chloride is a high-performance battery precursor material. It can be used to prepare cobalt hydroxide and cobalt tetroxide. The solubility of cobalt chloride increases with temperature. To obtain uniformly sized crystals from cobalt chloride solutions, a multi-effect evaporation followed by a reactor crystallization process is often used. However, this process produces crystals that are too small. Utility Model Content

[0003] The technical problem to be solved by the present application is that the cobalt chloride crystals crystallized in the existing cobalt chloride production process are relatively small. In order to solve this technical problem, a crystal preparation system capable of preparing larger cobalt chloride crystals is provided.

[0004] The technical solutions proposed in this application are:

[0005] A crystal preparation system, comprising:

[0006] A preheating unit, used for preheating the stock solution;

[0007] A concentration unit is provided downstream of the preheating unit and is used to concentrate the raw liquid;

[0008] a crystallization unit, disposed downstream of the concentration unit, for performing crystallization on the concentrated raw liquid to generate a slurry liquid and a clarified liquid;

[0009] An extraction unit is provided downstream of the crystallization unit and is used to separate and process the slurry to generate crystals;

[0010] The fine crystal removal unit is connected to the crystallization unit and is used to heat the clarified liquid and transport the heated clarified liquid back to the crystallization unit.

[0011] Furthermore, the crystallization unit includes a crystallizer and a thickener. The crystallizer is connected to the concentration unit and is used to crystallize the concentrated raw liquid to generate the slurry liquid and the clarified liquid; the fine crystal removal unit is connected to the crystallizer; the thickener is connected to the crystallizer and the extraction unit and is used to thicken the slurry liquid.

[0012] Furthermore, the crystallization unit also includes a cooler and a vacuum pump, both of which are connected to the crystallizer. The cooler is used to cool the material in the crystallizer, and the vacuum pump is used to vacuum the crystallizer.

[0013] Furthermore, the crystal preparation system further includes a liquid circulation unit, which is connected to the extraction unit and the preheating unit and is used to transport the liquid separated by the extraction unit to the preheating unit.

[0014] Furthermore, the liquid circulation unit includes a liquid circulation pump and an iron remover. The liquid circulation pump is connected to the extraction unit and the preheating unit, and is used to transport the liquid to the preheating unit. The iron remover is arranged between the liquid circulation pump and the preheating unit, and is used to remove iron from the liquid transported to the preheating unit.

[0015] Furthermore, the crystal preparation system further includes a drain pipe connected to the outlet end of the liquid circulation pump.

[0016] Furthermore, the preheating unit includes a condensate preheater and a steam preheater, and the steam preheater is arranged between the condensate preheater and the concentration unit.

[0017] Furthermore, the condensate outlet of the steam preheater is communicated with the condensate inlet of the condensate preheater.

[0018] Furthermore, the concentration unit includes an evaporator, a separator and a concentration circulation pump, the evaporator is connected to the preheating unit, the separator is connected to the evaporator and the crystallization unit, and the two ends of the concentration circulation pump are respectively connected to the separator and the evaporator, so that the raw liquid circulates in the evaporator and the separator.

[0019] Furthermore, the extraction unit includes a centrifuge and a liquid storage tank. The centrifuge is connected to the crystallization unit and the liquid storage tank to separate the crystals from the liquid and transport the liquid to the liquid storage tank.

[0020] In this crystal preparation system, while the raw liquid crystallizes in the crystallization unit, the clarified liquid is processed in the fine crystal removal unit, where the fine crystals are heated, dissolved, and removed. The clarified liquid is then transported back to the crystallization unit for further crystallization. This effectively removes fine crystals during the crystallization process, improves the uniformity of the cobalt chloride crystal size distribution in the extraction unit, and increases the size of the cobalt chloride crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application.

[0022] Figure 1 A schematic diagram of a crystal preparation system provided in one embodiment of the present application;

[0023] Figure 2 for Figure 1 Schematic diagram of the crystallizer in the crystal preparation system shown.

[0024] Description of labels:

[0025] 110. Preheating unit; 111. Condensate preheater; 112. Steam preheater; 120. Concentration unit; 121. Evaporator; 122. Separator; 123. Concentration circulation pump; 124. Scrubber; 125. Compressor; 126. First delivery pump; 130. Crystallization unit; 131. Crystallizer; 1311. Inner guide tube; 1312. Outer guide tube; 1313. Housing; 1314. Circulation gap; 1315. Agitator paddle; 1316. Salt leg; 132. Thickener; 133. Cooler; 134. Vacuum pump; 135. Second transfer pump; 140. Extraction unit; 141. Centrifuge; 142. Liquid storage tank; 150. Fine crystal removal unit; 151. Fine crystal removal circulation pump; 152. Fine crystal remover; 160. Liquid circulation unit; 161. Liquid circulation pump; 162. Iron remover; 170. Drain pipe. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0028] The present application provides a crystal preparation system, which can be applied to the preparation of cobalt chloride, such as cobalt chloride hexahydrate, and the cobalt chloride crystals prepared by the crystal preparation system are larger in size and have a more uniform particle size distribution.

[0029] like Figure 1As shown, the crystal preparation system includes a preheating unit 110, a concentration unit 120, a crystallization unit 130, and a collection unit 140. The preheating unit 110 is used to preheat the raw liquid. The concentration unit 120 is arranged downstream of the preheating unit 110 and is used to concentrate the preheated raw liquid. The crystallization unit 130 is arranged downstream of the concentration unit 120 and is used to crystallize the concentrated raw liquid to generate crystal slurry and clarified liquid. The collection unit 140 is arranged downstream of the crystallization unit 130 and is used to separate the crystal slurry to generate crystals.

[0030] Furthermore, the crystal preparation system includes a fine crystal removal unit 150, which is connected to the crystallization unit 130 and is used to heat the clarified liquid to remove fine crystals in the clarified liquid and then transport the heated clarified liquid back to the crystallization unit 130. In this way, fine crystals can be removed during the crystallization process, thereby increasing the size of the finished crystals while improving the uniformity of the particle size distribution.

[0031] Combined with this Figure 1 The process flow of the crystal preparation system in the above embodiment for preparing cobalt chloride crystals is described below: the mass concentration of the cobalt chloride stock solution is 15% and the temperature is 20-40°C. The preheating unit 110 receives the stock solution and preheats it to a temperature of 80-85°C. The stock solution then enters the concentration unit 120, which concentrates it to a mass concentration of 45%-55%. The stock solution then enters the crystallization unit 130, which crystallizes it, separating it into a slurry and a clarified liquid. Large crystals are located in the slurry, while fine crystals are located in the clarified liquid. As a result, the slurry sinks and the clarified liquid rises. The rising clarified liquid enters the fine crystal removal unit 150, which heats the clarified liquid to dissolve the fine crystals in the clarified liquid again, and then transports the clarified liquid back to the crystallization unit 130 to continue crystallization; the sinking slurry is transported to the extraction unit 140, and after separation treatment in the extraction unit 140, the cobalt chloride crystals are separated from the liquid.

[0032] Using the above-described crystal preparation system, while the raw liquid crystallizes in crystallization unit 130, the clarified liquid is processed by fine crystal removal unit 150, where the fine crystals are heated, dissolved, and removed. The clarified liquid is then transported back to crystallization unit 130 for further crystallization. This effectively removes fine crystals during the crystallization process, improves the uniformity of the cobalt chloride crystal size distribution in extraction unit 140, and increases the size of the cobalt chloride crystals.

[0033] In one embodiment, the preheating unit 110 includes a condensate preheater 111 and a steam preheater 112. The condensate preheater 111 is used to preliminarily preheat the raw liquid so that the temperature of the raw liquid is raised to 60-70°C. The steam preheater 112 is arranged between the condensate preheater 111 and the concentration unit 120 and is used to further heat the raw liquid so that the temperature of the raw liquid is raised to 80-85°C. Preferably, the condensate outlet of the steam preheater 112 is connected to the condensate inlet of the condensate preheater 111. In this way, after the steam in the steam preheater 112 completes heat exchange and condenses into condensed water, the temperature of the condensed water is still relatively high, so the condensed water is transported to the condensate preheater 111 for heat exchange with the raw liquid, thereby improving energy utilization and reducing energy consumption.

[0034] In one embodiment, the concentration unit 120 includes an evaporator 121, a separator 122 and a concentration circulation pump 123. The evaporator 121 is connected to the preheating unit 110, the separator 122 is connected to the evaporator 121 and the crystallization unit 130, and the two ends of the concentration circulation pump 123 are respectively connected to the separator 122 and the evaporator 121, so that the raw liquid circulates in the evaporator 121 and the separator 122.

[0035] Specifically, the raw liquid is preheated by the steam preheater 112 and heated to 80-85°C, then transported to the evaporator 121. Then, it is circulated in the evaporator 121 and the separator 122 by the concentration circulation pump 123. Evaporation and concentration are achieved during the circulation process. The evaporation and concentration temperature is 85-95°C, so that the mass concentration reaches 45%-55%. After the mass concentration reaches the requirement, the raw liquid is transported to the crystallization unit 130 for the next process.

[0036] Furthermore, the concentration unit 120 also includes a scrubbing tower 124 and a compressor 125. The air inlet end of the scrubbing tower 124 is connected to the separator 122, and the air outlet end is connected to the compressor 125. The air outlet end of the compressor 125 is connected to the separator 122. The scrubbing tower 124 is used to wash the steam after heat exchange in the separator 122. After washing, the steam enters the compressor 125. The compressor 125 raises the temperature of the steam to 90~95℃, and then transports it to the separator 122 again to concentrate the original liquid in the separator 122.

[0037] In one embodiment, the concentration unit 120 further includes a first delivery pump 126 . The first delivery pump 126 is disposed between the separator 122 and the crystallization unit 130 and is configured to deliver the concentrated raw liquid to the crystallization unit 130 .

[0038] In one embodiment, the crystallization unit 130 includes a crystallizer 131 and a thickener 132. The crystallizer 131 is connected to the concentration unit 120 and is used to crystallize the concentrated raw liquid to generate slurry and clarified liquid; the fine crystal removal unit 150 and the thickener 132 are both connected to the crystallizer 131. The fine crystal removal unit 150 can obtain the clarified liquid in the crystallizer 131, remove the fine crystals therein by heating, and then transport the clarified liquid back to the crystallizer 131; the thickener 132 is also connected to the downstream extraction unit 140. The thickener 132 can obtain the slurry in the crystallizer 131, thicken the slurry, and then transport the thickened slurry to the downstream extraction unit 140 to facilitate the extraction of downstream crystals.

[0039] Furthermore, the crystallization unit 130 also includes a cooler 133 and a vacuum pump 134, both of which are connected to the crystallizer 131, and the cooler 133 is used to cool the material in the crystallizer 131 so that the temperature of the raw liquid drops to 40~45°C; the vacuum pump 134 is used to vacuum the crystallizer 131 to reduce the pressure in the crystallizer 131, thereby reducing the boiling point temperature of the liquid in the raw liquid in the crystallizer 131, further concentrating the raw liquid, and realizing the precipitation of cobalt chloride crystals in the raw liquid.

[0040] Please also see Figure 2 In one embodiment, the crystallizer 131 includes a coaxially arranged inner draft tube 1311 and outer draft tube 1312, and a housing 1313 disposed outside the outer draft tube 1312. The housing 1313 is connected to the lower portion of the outer draft tube 1312, and the inner wall of the housing 1313 is spaced from the outer portion of the outer draft tube 1312 to form a circulation gap 1314. The bottom of the inner draft tube 1311 extends into the interior of the housing 1313, and the top extends into the outer draft tube 1312. A stirring paddle 1315 is also provided below the interior of the inner draft tube 1311. The stirring paddle 1315 is used to stir the raw liquid, causing it to flow upward within the inner draft tube 1311, thereby stirring the raw liquid within the crystallizer 131.

[0041] During use, a salt leg 1316 is formed below the shell 1313, the concentration unit 120 is connected to the liquid inlet at the bottom of the salt leg 1316, the thickener 132 is connected to the slurry outlet on the side of the salt leg 1316, and the fine crystal removal unit 150 is connected to the side of the shell 1313 and is connected to the circulation gap 1314. In this way, the concentrated raw liquid is input into the crystallizer 131 through the liquid inlet, and the stirring paddle 1315 inside the inner guide tube 1311 is activated to guide the raw liquid along the inner surface of the crystallizer 131. Figure 1The liquid circulates in the direction of the arrows. During this circulation, the liquid evaporates, the concentration of the raw liquid continues to rise, and it is separated into a slurry and a clarified liquid. The clarified liquid is located in the upper layer. The clarified liquid in the circulation gap 1314 enters the fine crystal removal unit 150, while the slurry sinks to the salt leg 1316 and is transported to the production unit 140. It can be confirmed that the slurry contains liquid and precipitated cobalt chloride crystals.

[0042] It should be explained that the liquid inlet is located at the bottom of the salt leg 1316, and the crystals in the slurry are also deposited at the salt leg 1316, so the crystals can also be washed during the liquid inlet process to remove some fine crystals and other impurities on the surface of the crystals.

[0043] In one embodiment, the crystallization unit 130 further includes a second delivery pump 135, which is disposed between the crystallizer 131 and the thickener 132 and is used to guide the crystal slurry in the crystallizer 131 to be delivered to the thickener 132. Figure 1 In the illustrated embodiment, the first delivery pump 126 is connected to the slurry outlet on the side of the salt leg 1316. It should be noted that the residence time of the raw liquid in the crystallizer 131 is 3 to 8 hours, and the solids content of the slurry discharged from the salt leg 1316 is greater than 30%. The slurry is then thickened in the thickener 132 and then delivered to the extraction unit 140.

[0044] In one embodiment, the fine crystal removal unit 150 includes a fine crystal removal circulation pump 151 and a fine crystal remover 152. The fine crystal removal circulation pump 151 is connected to the shell 1313 in the crystallizer 131 and is in communication with the circulation gap 1314, and is used to guide the clarified liquid in the crystallizer 131 to be transported to the fine crystal remover 152. The fine crystal remover 152 can heat the clarified liquid, and the liquid outlet end of the fine crystal remover 152 is connected to the crystallizer 131, so that the fine crystals in the clarified liquid are dissolved again by heating, and the clarified liquid with the fine crystals removed re-enters the crystallizer 131.

[0045] It should be noted that in this embodiment, the fine crystal remover 152 also uses steam heat exchange to heat the clarified liquid. The steam preheater 112, the fine crystal remover 152, and the evaporator 121 in the concentration unit 120 are all heated by steam and produce relatively high-temperature condensate. To further improve energy efficiency, the condensate from the fine crystal remover 152 and the evaporator 121 can be transferred to the condensate preheater 111 to reuse the heat in the condensate.

[0046] In one embodiment, the extraction unit 140 includes a centrifuge 141 and a liquid storage tank 142. The centrifuge 141 is connected to the crystallization unit 130 and the liquid storage tank 142 to separate the crystals from the liquid in the slurry and transfer the liquid to the liquid storage tank 142. In actual application, the centrifuge 141 is connected to the thickener 132. The slurry is centrifuged and dehydrated by the centrifuge 141 to obtain cobalt chloride crystals, and the dehydrated liquid is transferred to the liquid storage tank 142. It should be noted that the temperature of the crystals obtained by the centrifuge 141 is 25-40°C.

[0047] In one embodiment, the crystal preparation system further includes a liquid circulation unit 160, which is connected to the extraction unit 140 and the preheating unit 110 and is configured to transport the liquid separated by the extraction unit 140 to the preheating unit 110. The liquid transported from the liquid circulation unit 160 to the preheating unit 110 also contains some cobalt chloride, thereby improving the production rate of cobalt chloride.

[0048] Furthermore, liquid circulation unit 160 includes a liquid circulation pump 161 and an iron remover 162. Liquid circulation pump 161 is connected to liquid storage tank 142 and condensate preheater 111, and is used to transport liquid in liquid storage tank 142 to condensate preheater 111. Iron remover 162 is disposed between liquid circulation pump 161 and condensate preheater 111, and is used to remove iron from the liquid transported to condensate preheater 111, thereby removing magnetic impurities, such as iron, in the liquid. Specifically, iron remover 162 is an electromagnetic iron remover 162, and has a magnetic field strength of 5,000 to 10,000 gauss.

[0049] In one embodiment, the crystal preparation system further includes a drain pipe 170 connected to the outlet end of the liquid circulation pump 161 to drain the liquid in the liquid storage tank 142. It is understood that after the liquid in the liquid storage tank 142 circulates multiple times, the remaining cobalt chloride is relatively small and has low reuse value. To prevent excessive accumulation of liquid in the liquid storage tank 142, the liquid can be pumped to the drain pipe 170 via the liquid circulation pump 161 for discharge.

[0050] It is certain that the outlet of the liquid circulation pump 161 is provided with two branches, one of which is provided with an iron remover 162, and the other branch is a drain pipe 170. To achieve alternating conduction of the two branches, control valves can be provided on both branches. That is, when liquid recycling is required, the control valve on the branch corresponding to the iron remover 162 is opened, and the control valve on the branch corresponding to the drain pipe 170 is closed; when liquid discharge is required, the control valve on the branch corresponding to the drain pipe 170 is opened, and the control valve on the branch corresponding to the iron remover 162 is closed.

[0051] In order to facilitate understanding of the technical solution of this application, Figure 1Taking the preparation of cobalt chloride crystals as an example, the preparation process of the crystal preparation system in the above embodiment is described:

[0052] The raw liquid, with a mass concentration of 15% and a temperature of 35°C, enters condensate preheater 111 and is preheated to 65°C. It then enters steam preheater 112 and is preheated to 85°C. After preheating, it enters evaporator 121 of concentration unit 120 and is driven by concentration circulation pump 123 to circulate between evaporator 121 and separator 122. During this circulation process, the raw liquid is evaporated and concentrated to a mass concentration of 45% to 55%. The concentrated raw liquid is then transported to crystallizer 131 by first delivery pump 126.

[0053] The raw liquid entering the crystallizer 131 circulates under the action of the stirring paddle 1315. During the flow, the temperature of the raw liquid decreases, and the liquid evaporates and further concentrates, separating into a clarified liquid and a crystal slurry. The clarified liquid in the circulation gap 1314 is transported to the fine crystal remover 152 by the action of the fine crystal removal circulation pump 151. Then, the temperature is increased by the heating of the fine crystal remover 152, so that the fine crystals in the clarified liquid are dissolved and removed. It is then transported back to the crystallizer 131 for further concentration and crystallization. The crystal slurry in the crystallizer 131 sinks, and the crystals in the crystal slurry sink to the salt leg 1316. They are then transported to the thickener 132 by the action of the second delivery pump 135, and the thickener 132 further thickens the crystal slurry.

[0054] The slurry then enters centrifuge 141 for centrifugal dehydration to produce cobalt chloride crystals. The dehydrated liquid is then transferred to liquid storage tank 142. The liquid in liquid storage tank 142 is removed by iron removal in iron remover 162 under the action of liquid circulation pump 161 before being transferred back to condensate preheater 111 for reuse of the cobalt chloride in the liquid. If the liquid in liquid storage tank 142 is high and its utilization value is low, some of the liquid is discharged through drain pipe 170.

[0055] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A crystal preparation system, characterized in that: include: A preheating unit, used for preheating the stock solution; A concentration unit is provided downstream of the preheating unit and is used to concentrate the raw liquid; a crystallization unit, disposed downstream of the concentration unit, for performing crystallization on the concentrated raw liquid to generate a slurry liquid and a clarified liquid; An extraction unit is provided downstream of the crystallization unit and is used to separate and process the slurry to generate crystals; The fine crystal removal unit is connected to the crystallization unit and is used to heat the clarified liquid and transport the heated clarified liquid back to the crystallization unit.

2. The crystal preparation system according to claim 1, characterized in that The crystallization unit includes a crystallizer and a thickener. The crystallizer is connected to the concentration unit and is used to crystallize the concentrated raw liquid to generate the crystal slurry and the clarified liquid; the fine crystal removal unit is connected to the crystallizer; the thickener is connected to the crystallizer and the extraction unit and is used to thicken the crystal slurry.

3. The crystal preparation system according to claim 2, characterized in that: The crystallization unit further includes a cooler and a vacuum pump, both of which are connected to the crystallizer. The cooler is used to cool the material in the crystallizer, and the vacuum pump is used to evacuate the crystallizer.

4. The crystal preparation system according to claim 1, characterized in that: The crystal preparation system further includes a liquid circulation unit, which is connected to the extraction unit and the preheating unit and is used to transport the liquid separated by the extraction unit to the preheating unit.

5. The crystal preparation system according to claim 4, characterized in that: The liquid circulation unit includes a liquid circulation pump and an iron remover. The liquid circulation pump is connected to the extraction unit and the preheating unit and is used to transport the liquid to the preheating unit. The iron remover is arranged between the liquid circulation pump and the preheating unit and is used to remove iron from the liquid transported to the preheating unit.

6. The crystal preparation system according to claim 5, characterized in that: The crystal preparation system further includes a liquid discharge pipe connected to the outlet end of the liquid circulation pump.

7. The crystal preparation system according to claim 1, characterized in that: The preheating unit includes a condensate preheater and a steam preheater, and the steam preheater is arranged between the condensate preheater and the concentration unit.

8. The crystal preparation system according to claim 7, characterized in that: The condensate outlet of the steam preheater is communicated with the condensate inlet of the condensate preheater.

9. The crystal preparation system according to claim 1, characterized in that: The concentration unit includes an evaporator, a separator and a concentration circulation pump. The evaporator is connected to the preheating unit, the separator is connected to the evaporator and the crystallization unit, and the two ends of the concentration circulation pump are respectively connected to the separator and the evaporator to allow the raw liquid to circulate in the evaporator and the separator.

10. The crystal preparation system according to claim 1, characterized in that: The extraction unit includes a centrifuge and a liquid storage tank. The centrifuge is connected to the crystallization unit and the liquid storage tank to separate the crystals from the liquid and transport the liquid to the liquid storage tank.

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