CN111960446A - Method for continuously producing high-purity lithium carbonate - Google Patents

Method for continuously producing high-purity lithium carbonate Download PDF

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CN111960446A
CN111960446A CN202010943455.2A CN202010943455A CN111960446A CN 111960446 A CN111960446 A CN 111960446A CN 202010943455 A CN202010943455 A CN 202010943455A CN 111960446 A CN111960446 A CN 111960446A
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pyrolysis
lithium carbonate
liquid
hydrogenation
purity
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CN111960446B (en
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陈世鹏
计彦发
多金鹏
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Gansu Ruisike New Materials Co ltd
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    • C01DCOMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00Lithium compounds
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Abstract

The invention belongs to the field of inorganic salt chemical industry, and relates to a method for continuously producing high-purity lithium carbonate, which comprises the processes of pulping, hydrogenation, filtration, pyrolysis and the like, wherein the temperature of a reaction kettle is kept relatively constant in the pyrolysis process, and the hydrogenation liquid is pyrolyzed by keeping 1/4-1/3 pyrolysis base liquid in the reaction kettle and controlling the dropping flow rate of the hydrogenation liquid; compared with the prior art that the temperature of the reaction kettle needs to be repeatedly increased and decreased, the temperature of the reaction kettle does not need to be increased and decreased in the pyrolysis process, and the waiting time generated in the temperature increasing and decreasing process of the reaction kettle does not exist, so that the pyrolysis process can be continuously performed, the continuous production can be realized by using the method, and the energy consumption is low.

Description

Method for continuously producing high-purity lithium carbonate
Technical Field
The invention belongs to the field of inorganic salt chemical industry, relates to a preparation method of high-purity lithium carbonate, and particularly relates to a method for continuously producing high-purity lithium carbonate.
Background
The high-purity lithium carbonate is widely applied to the fields of electronic materials, medicines, reagents and the like, and particularly the demand of the field of electronic materials is rapidly increased; in the field of electronic materials, high-purity lithium carbonate is used as a solid wave vibration element, the material used in the element is lithium niobate and lithium tantalate single crystal, and the lithium niobate and lithium tantalate are made of niobium pentoxide, tantalum pentoxide and high-purity lithium carbonate. Lithium tantalate can also be used in thermoelectric detection elements, military, medical, fire alarm, disaster prevention and other fields. In addition, the dosage of reagents and medicines is continuously expanded, and the market prospect is good.
The preparation process of high-purity lithium carbonate is always the focus of research, the currently commonly used method is basically the same as the method for preparing battery-grade lithium carbonate, and is three main steps of hydrogenation, ion exchange impurity removal and pyrolysis, for example, a patent with the publication number of CN102531002B discloses a method for purifying lithium carbonate, lithium carbonate is purified through hydrogenation, ion exchange and pyrolysis, in the pyrolysis process, an inventor finds that the temperature rise rate has great influence on the main content of a product, when the temperature rise rate exceeds 1 ℃/min, the precipitated product particles are obviously larger than the product obtained by slow heating, and the product particles are wrapped by impurities, so that the main content of the product is reduced, and aiming at the phenomenon, the temperature rise rate needs to be strictly controlled to be 0.5-1 ℃/min in the pyrolysis process. Namely, before pyrolysis, the temperature in the reaction kettle needs to be reduced to room temperature every time, after the hydrogenated liquid is added into the reaction kettle, the temperature of the reaction kettle is strictly controlled to be increased to 70-90 ℃ for pyrolysis, and due to the fact that the reaction kettle needs to be repeatedly heated and cooled, the method cannot realize continuous production and is high in energy consumption. In addition, as can be seen from the examples section of this patent, the purity of the lithium carbonate purified by this method is between 99.81% and 99.86%, and the purity of the lithium carbonate does not meet the requirement of high purity (Li) lithium carbonate2CO3The content is more than or equal to 99.90 percent).
In addition, a patent with publication number CN109942009A discloses a method for preparing battery-grade lithium carbonate, which adopts series packed tower devices, and increases lithium carbonate slurry and CO by gas-liquid countercurrent contact2The contact area and the chemical reaction power of the gas improve the hydrogenation rate of the lithium carbonate, and the content of sulfate radicals in the product is reduced by adding a sulfate radical complexing agent into a reaction system in the pyrolysis process; the sodium hydroxide solution is used for washing in the washing process, the polycrystalline structure is damaged, the impurity content is reduced, and the prepared lithium carbonate reaches the standard of industrial battery-grade lithium carbonate products (Li is more than or equal to 99.50%)2CO3Content is less than 99.90%), but because the method additionally introduces sulfate radical complexing agent and sodium hydroxide into the system, i.e. other impurities are introduced into the reaction system, the purity of the lithium carbonate prepared by the method cannot be further improved by repeatedly extracting lithium mother liquor, i.e. the purity of the lithium carbonate prepared by the method can reach the battery level and cannot meet the purity requirement of high-purity lithium carbonate (the purity of Li can not reach the battery level)2CO3The content is more than or equal to 99.90 percent). In addition, as can be seen from the disclosure of the patent specification, in the pyrolysis process, the temperature needs to be controlled to be above 70 ℃, and the heating temperature rise process is not less than 30min, that is, in the pyrolysis process, the temperature rise rate also needs to be controlled, that is, in the pyrolysis process, repeated temperature rise and drop operations need to be performed on the reaction kettle, which is not convenient for continuous production of lithium carbonate.
In summary, the existing lithium carbonate purification methods all require repeated temperature rise and drop operations on the reaction kettle in the pyrolysis process, which is not beneficial to the continuous production of lithium carbonate and has high energy consumption; in addition, external impurities are often introduced in the purification process of the existing lithium carbonate, which is not beneficial to further improvement of the purity of the lithium carbonate.
Disclosure of Invention
The invention aims to provide a method for continuously producing high-purity lithium carbonate, which has the advantages of low energy consumption in the preparation process and high purity of the prepared lithium carbonate.
Based on the purpose, the invention adopts the following technical scheme: a method for continuously producing high-purity lithium carbonate comprises the following steps:
(1) uniformly mixing industrial-grade lithium carbonate and water according to the proportion of 1g (18-25) mL to prepare a slurry;
(2) equally dividing the slurry into a plurality of hydrogenation towers which are connected in series; continuously introducing high-purity CO into the hydrogenation tower from the bottoms of the two hydrogenation towers arranged at two ends respectively2Hydrogenating to obtain hydrogenated liquid; the hydrogenation tower has no exhaust gas in the hydrogenation process, so that the introduced high-purity carbon dioxide is fully utilized in the hydrogenation towers which are connected in series;
(3) filtering the obtained hydrogenated liquid to remove insoluble impurities;
(4) adding the hydrogenated liquid filtered in the step (3) into a pyrolysis container to serve as pyrolysis base liquid, wherein the volume of the pyrolysis base liquid is 1/4-1/3 of the pyrolysis capacity of the pyrolysis container; adding high-purity 4N-grade lithium carbonate into the pyrolysis base solution, controlling the temperature in a pyrolysis container to be 98-100 ℃, slowly dropwise adding the filtered hydrogenation solution into the pyrolysis container to pyrolysis capacity, carrying out heat preservation reaction at the temperature of 98-100 ℃ for 0.5-1 h to prepare pyrolysis solution, releasing 2/3-3/4 volume of pyrolysis solution, filtering, collecting precipitate, washing the precipitate, and calcining at the temperature of 450 ℃ to prepare high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is used as pyrolysis base liquid for the next reaction;
(5) slowly dropwise adding the hydrogenated liquid filtered in the step (3) into the residual pyrolysis liquid in the pyrolysis container in the step (4) to pyrolysis capacity, carrying out heat preservation reaction for 0.5-1 h at the temperature of 98-100 ℃ to obtain pyrolysis liquid, releasing 2/3-3/4 volume of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate, and calcining at the temperature of 450 ℃ to obtain high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is continuously used as pyrolysis base liquid for the next reaction;
(6) and (5) repeating the steps (1) to (5) to continuously produce the high-purity lithium carbonate.
Further, CO in the step (2)2The introduction rate of the catalyst is based on the volume of the slurry liquid in the hydrogenation tower connected with the catalyst, and each liter of the slurry liquid corresponds to CO2The feeding rate of (2) is 0.1 to 0.8L/min.
Further, each liter of slurry solution corresponds to CO2The feeding rate of (2) is 0.2 to 0.6L/min.
Further, each liter of slurry solution corresponds to CO2The feed rate of (2) was 0.3L/min.
Further, in the process of slowly dripping the filtered hydrogenation solution into the pyrolysis container in the step (4) and the step (5), the volume of the dripping hydrogenation solution per minute is 0.5-2% of the pyrolysis capacity.
Further, 2/3 volumes of pyrolysis liquid released upon completion of the pyrolysis in the step (4) and the step (5) were filtered to prepare high-purity lithium carbonate, and 1/3 of pyrolysis liquid was reserved as a pyrolysis base liquid for the next reaction.
Further, the high-purity 4N-grade lithium carbonate and the pyrolysis base solution in the step (4) are added into the pyrolysis base solution according to the proportion of (1-2) g: 1L.
Further, the ratio of the industrial-grade lithium carbonate to the water in the step (1) is 1g (20-23) mL.
Further, the ratio of technical grade lithium carbonate to water in step (1) was 1g:20 mL.
Further, the number of the hydrogenation towers which are connected in series in the step (2) is 3-10.
Further, the number of hydrogenation columns connected in series is 4 to 6, and more preferably 5.
Further, the filter aperture of the filter adopted in the filtering in the step (3) is 0.1-1 μm.
Compared with the prior art, the invention has the beneficial effects that:
(1) the temperature of a reaction kettle is kept relatively constant in the pyrolysis process, 1/4-1/3 pyrolysis base liquid is kept in the reaction kettle, the dropping flow rate of the hydrogenation liquid is controlled, and the hydrogenation liquid is pyrolyzed; compared with the prior art that the temperature of the reaction kettle needs to be repeatedly increased and decreased, the temperature of the reaction kettle does not need to be increased and decreased in the pyrolysis process, and the waiting time generated in the temperature increasing and decreasing process of the reaction kettle does not exist, so that the pyrolysis process can be continuously performed, the continuous production can be realized by using the method, and the energy consumption is low.
(2) The invention prepares high-purity lithium carbonate by pulping, hydrogenating, filtering and pyrolyzing industrial-grade lithium carbonate, and no external impurities are introduced in the preparation process, so that the lithium carbonate with higher purity can be prepared after being repeatedly purified by the purification method of the invention, and the purity of the lithium carbonate prepared by the three-time purification of the method of the invention is not lower than 99.99 percent by taking the industrial-grade lithium carbonate with the purity of 98.4 percent as an example, therefore, the quality of the lithium carbonate prepared by the method of the invention is superior to the standard that the purity of the lithium carbonate specified in the color industry YS/T546-2008 is 99.99 percent.
(3) The invention adopts a plurality of hydrogenation towers which are connected in series end to end, carbon dioxide is introduced into the hydrogenation towers which are connected in series through the bottoms of the two hydrogenation towers which are arranged at two ends, the carbon dioxide enters the interior of the next hydrogenation tower through a pipeline which is communicated with the bottom of the next hydrogenation tower through the top, namely the carbon dioxide is introduced from the bottoms of the hydrogenation towers, so that the carbon dioxide and the hydrogenation liquid flow in the reverse direction and are fully contacted for hydrogenation reaction, and no exhaust is arranged in the hydrogenation process, so that the introduced carbon dioxide can be fully and effectively utilized, and the utilization rate of the carbon dioxide and the hydrogenation efficiency are improved.
(4) According to the invention, the same amount of slurry liquid is filled in the hydrogenation towers which are connected in series, and carbon dioxide with the same flow rate is introduced from the hydrogenation towers at two ends, so that the hydrogenation completion time of the two hydrogenation towers at two ends is similar, the amount of the hydrogenated liquid after hydrogenation can meet the continuous pyrolysis requirement of a reaction kettle, and the continuous production of high-purity lithium carbonate is facilitated.
Drawings
FIG. 1 is a schematic view of the process of the present invention.
Detailed Description
Example 1 investigation of different CO2The manner of introduction and the influence of the rate of introduction on the hydrogenation efficiency
A method for continuously producing high-purity lithium carbonate, as shown in fig. 1, comprising the following steps:
(1) industrial-grade lithium carbonate and ultrapure water were mixed uniformly in a ratio of 1g to 20mL to prepare 75L of slurry, where the main content and impurity content of the industrial-grade lithium carbonate in this example are shown in table 1, and the content of lithium carbonate in the industrial-grade lithium carbonate is 99.4%.
(2) Equally dividing the slurry into five hydrogenation towers which are sequentially connected in series end to end, namely, the top of the previous hydrogenation tower is connected with the bottom of the next hydrogenation tower through a ventilation pipeline for carrying out CO in the hydrogenation process2Gas transmission; the volume of the slurry in each hydrogenation tower is 15L; continuously introducing high-purity CO into the hydrogenation tower from the bottoms of the two hydrogenation towers arranged at two ends respectively2Hydrogenating to obtain hydrogenated liquid; and the hydrogenation tower has no exhaust gas in the hydrogenation process, so that the introduced high-purity carbon dioxide is hydrogen in series connection with each otherThe chemical tower is fully utilized; CO in hydrogenation tower arranged at two ends2The feeding rate of the hydrogenation tower is determined by the volume of the slurry liquid in a single hydrogenation tower and is positively correlated with the volume of the slurry liquid; CO control according to volume of slurry liquid added into hydrogenation tower2The rate of passage of (1).
(3) The obtained hydrogenated liquid was filtered through a microfilter having a filtration pore size of 0.22 μm to remove insoluble impurities.
(4) Adding 1/3 volume of hydrogenated liquid filtered in the step (3) into a pyrolysis container as pyrolysis base liquid, wherein the capacity of the pyrolysis container is 15L, and the amount of hydrogenated liquid added as primary pyrolysis base liquid is 5L; adding high-purity 4N-grade lithium carbonate (the purity of lithium carbonate is more than or equal to 99.99%) into the pyrolysis base solution, wherein the ratio of the added high-purity 4N-grade lithium carbonate to the pyrolysis base solution is 1g:1L, namely the amount of the added high-purity 4N-grade lithium carbonate into 5L of the pyrolysis base solution is 5g, and the purpose of adding the high-purity 4N-grade lithium carbonate is to serve as seed crystals to induce the crystallization and precipitation of the lithium carbonate in the pyrolysis reaction system; and controlling the temperature in the pyrolysis container to be 100 ℃, slowly dripping the filtered hydrogenation liquid into the pyrolysis container to pyrolysis capacity, wherein the dripping flow rate of the hydrogenation liquid is 0.11L/min, namely dripping 10L of the hydrogenation liquid to be dripped is completed within about 1.5h, and if the volume of the hydrogenation liquid dripped per minute is 0.73% of the pyrolysis capacity according to the pyrolysis capacity.
Then, reacting for 1 hour at 100 ℃ to obtain pyrolysis liquid, releasing 2/3 volumes of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate with organic alcohol such as absolute ethyl alcohol or absolute methyl alcohol, or glycerol or n-butyl alcohol, filtering, and calcining at 450 ℃ to obtain high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is used as pyrolysis base liquid for the next reaction; the reaction kettle adopts an oil bath heating mode in the pyrolysis process, so that the heat preservation performance of oil bath heating is better and the heat loss is effectively avoided compared with steam heating or electric heating.
(5) Dropwise adding the hydrogenated liquid filtered in the step (3) into the residual pyrolysis liquid in the pyrolysis container in the step (4) at the flow rate of 0.11L/min to the pyrolysis capacity, keeping the temperature for reaction for 1h at 100 ℃ to prepare pyrolysis liquid, releasing 2/3 volumes of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate, and calcining at 450 ℃ to prepare high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is continuously used as pyrolysis base liquid for the next reaction.
(6) And (5) repeating the steps (1) to (5) to continuously produce the high-purity lithium carbonate.
Figure 970806DEST_PATH_IMAGE002
Referring to the method for continuously producing high-purity lithium carbonate in the steps (1) - (6), high-purity lithium carbonate is prepared according to specific parameters given in table 2 and is respectively marked as samples 1-7.
Referring to the continuous production method of high-purity lithium carbonate in steps (1), (3) to (6) and the preparation of the comparative sample with the parameters given in Table 2, the preparation process of the comparative sample differs from that of samples 1-1 to 1-7 in step (2).
The step (2) in the preparation process of the comparison sample is as follows: equally dividing the slurry into five hydrogenation towers which are sequentially connected in series end to end, namely, the top of the previous hydrogenation tower is connected with the bottom of the next hydrogenation tower through a ventilation pipeline for carrying out CO in the hydrogenation process2Gas transmission; the volume of the slurry in each hydrogenation tower is 15L; continuously introducing high-purity CO into the hydrogenation tower from the bottom of the first hydrogenation tower2High purity CO2Sequentially conveying the mixture from the first hydrogenation tower to the last hydrogenation tower, escaping from the top of the last hydrogenation tower, introducing the mixture into the bottom of the first hydrogenation tower, and carrying out high-purity CO2The slurry liquid in the hydrogenation tower is subjected to hydrogenation reaction to prepare hydrogenation liquid; CO 22The feeding rate of the hydrogenation tower is determined by the volume of the slurry liquid in a single hydrogenation tower and is positively correlated with the volume of the slurry liquid; CO control according to volume of slurry liquid added into hydrogenation tower2The rate of passage of (1).
Setting different CO in hydrogenation reaction process2Observing CO at different flow rates2For hydrogenation completion time, CO2The effect of the utilization and hydrogenation efficiency of (1) is shown in Table 2, wherein the hydrogenation time refers to the slurrying in five hydrogenation columns in seriesThe time taken for the hydrogenation to complete was complete.
As is clear from the results of samples 1-1 to 1-7 in Table 2, the following CO was added2Increase in the feed rate and decrease in the hydrogenation time, but CO2The utilization rate of (A) is in a descending trend; from the results of samples 1-2 and the comparative sample, it can be seen that the same CO is used2At the feed rate, the hydrogenation time of samples 1-2 was reduced by 37% compared to the control, and CO was reduced by2The utilization rate of the method is improved by 35 percent.
Figure DEST_PATH_IMAGE003
Example 2 discussion of the effect of different hydrogenation solution drop rates on the purity of lithium carbonate produced
A method for continuously producing high-purity lithium carbonate comprises the following steps:
(1) industrial-grade lithium carbonate and ultrapure water were mixed uniformly according to a ratio of 1g:25mL to prepare 100L of slurry, wherein the content of lithium carbonate in the industrial-grade lithium carbonate in this example was 99.0%.
(2) Equally dividing the slurry into five hydrogenation towers which are sequentially connected in series, namely, the top of the former hydrogenation tower is connected with the bottom of the latter hydrogenation tower through a vent pipeline for carrying out CO in the hydrogenation process2Gas transmission; the volume of the slurry in each hydrogenation tower is 20L; continuously introducing high-purity CO from the bottom of the first hydrogenation tower into the hydrogenation towers connected in series2CO escaping from the last hydrogenation column2The gas is returned to the first hydrogenation tower and is introduced from the bottom of the first hydrogenation tower, so that CO is in the hydrogenation tower2The gas and the slurry liquid are in countercurrent contact, and the slurry liquid is hydrogenated to prepare hydrogenated liquid in such a circulating way; the hydrogenation tower has no exhaust gas in the hydrogenation process, so that the introduced high-purity carbon dioxide is fully utilized in the hydrogenation towers which are connected in series; CO in hydrogenation tower2The feeding rate of the hydrogenation tower is determined by the volume of the slurry liquid in a single hydrogenation tower and is positively correlated with the volume of the slurry liquid; introducing CO into the hydrogenation tower2The rate of (a) is 4L/min, namely CO corresponding to each liter of slurry liquid in a single hydrogenation tower2The feed rate of (2) was 0.2L/min.
(3) The obtained hydrogenation solution was filtered through a microfilter having a filtration pore size of 0.1 μm to remove insoluble impurities.
(4) Adding 1/4 volume of hydrogenated liquid filtered in the step (3) into a pyrolysis container as pyrolysis base liquid, wherein the capacity of the pyrolysis container is 20L, and the amount of hydrogenated liquid added as primary pyrolysis base liquid is 5L; adding high-purity 4N-grade lithium carbonate (the purity of lithium carbonate is more than or equal to 99.99%) into the pyrolysis base solution, wherein the ratio of the added high-purity 4N-grade lithium carbonate to the pyrolysis base solution is 1g:1L, namely the amount of the added high-purity 4N-grade lithium carbonate into 5L of the pyrolysis base solution is 5g, and the purpose of adding the high-purity 4N-grade lithium carbonate is to serve as seed crystals to induce the crystallization and precipitation of the lithium carbonate in the pyrolysis reaction system; controlling the temperature in the pyrolysis container to be 100 ℃, slowly dripping the filtered hydrogenation solution into the pyrolysis container to reach pyrolysis capacity, and controlling the dripping flow rate of the hydrogenation solution, wherein the dripping flow rate of the hydrogenation solution is shown in table 2.
Then, reacting at 100 ℃ for 1 hour to prepare pyrolysis liquid, releasing 4/5 volumes of pyrolysis liquid, filtering and collecting precipitate, namely releasing 15L of pyrolysis liquid, filtering and collecting precipitate, washing the precipitate with organic alcohol such as absolute ethyl alcohol or absolute methyl alcohol, or glycerol or n-butyl alcohol, filtering, drying, and calcining at 450 ℃ to prepare high-purity lithium carbonate; the residual 5L of pyrolysis liquid in the pyrolysis container is used as pyrolysis base liquid for the next reaction; the reaction kettle adopts an oil bath heating mode in the pyrolysis process, so that the heat preservation performance of oil bath heating is better and the heat loss is effectively avoided compared with steam heating or electric heating.
(5) Adding 15L of the hydrogenated liquid filtered in the step (3) into the residual pyrolysis liquid in the pyrolysis container in the step (4) according to the same dropwise adding flow rate of the hydrogenated liquid in the step (4) to a pyrolysis capacity of 20L, carrying out heat preservation reaction at 100 ℃ for 1h to obtain pyrolysis liquid, releasing 15L of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate, and calcining at 450 ℃ to obtain high-purity lithium carbonate; the remaining 5L of pyrolysis liquid in the pyrolysis container continues to be used as pyrolysis base liquid for the next reaction.
(6) And (5) repeating the steps (1) to (5) to continuously produce the high-purity lithium carbonate.
The dropping flow rates of different hydrogenation solutions were set during the pyrolysis, and the influence of the hydrogenation solutions with different dropping flow rates on the purity of lithium carbonate finally obtained by purification was observed, and the dropping flow rates of the hydrogenation solutions and the purity of lithium carbonate finally obtained by purification are shown in table 3.
As can be seen from Table 3, when the acceleration of the hydrogenation liquid drop is 0.6-1.5% of the pyrolysis capacity, the dropping time is completed to 50-125min, i.e. the reaction time is short, and the purity of the obtained lithium carbonate is higher than 99.994%; when the dropping speed is more than 1.5 percent of the pyrolysis capacity, the dropping time is less than 50min, and the obtained lithium carbonate barely reaches the 4N-grade purity; when the dropping speed is 0.1 percent of the pyrolysis capacity, the dropping completion time is 750min, and the hydrogenation solution is reacted at the high temperature of 95 ℃ all the time, so that a large amount of hydrogenation solution is evaporated for a long time to reduce the liquid volume, impurities are enriched in lithium carbonate, and the content is reduced.
Figure 684684DEST_PATH_IMAGE004
Example 3
A method for continuously producing high-purity lithium carbonate comprises the following steps:
(1) and uniformly mixing industrial-grade lithium carbonate and ultrapure water according to a certain proportion to prepare 200L of slurry.
(2) Equally dividing the slurry into five hydrogenation towers which are connected in series end to end, wherein the slurry amount in each hydrogenation tower is 40L; the top of the former hydrogenation tower is connected with the bottom of the latter hydrogenation tower through a pipeline for carrying out CO in the hydrogenation process2Gas transmission; continuously introducing high-purity CO into the hydrogenation tower from the bottoms of the two hydrogenation towers arranged at two ends respectively2Hydrogenating to obtain hydrogenated liquid; the hydrogenation tower has no exhaust gas in the hydrogenation process, so that the introduced high-purity carbon dioxide is fully utilized in the hydrogenation towers which are connected in series; CO in hydrogenation tower arranged at two ends2The feeding rate of the hydrogenation tower is determined by the volume of the slurry liquid in a single hydrogenation tower and is positively correlated with the volume of the slurry liquid; CO control according to volume of slurry liquid added into hydrogenation tower2At a rate of introduction of, per liter of pulpCO corresponding to chemical liquid2The introduction rate of (2) was 0.3L/min, that is, CO introduced from each of the two hydrogenation columns at both ends was2The flow rates of (A) and (B) were all 6L/min.
(3) The obtained hydrogenation solution was filtered through a microfilter having a filtration pore size as shown in table 3 to remove insoluble impurities.
(4) Adding 1/4 volume of hydrogenation liquid filtered in the step (3) into a pyrolysis container as pyrolysis base liquid, wherein the volume of the pyrolysis container is 40L, and the amount of the added hydrogenation liquid is 10L; adding high-purity 4N-grade lithium carbonate (the purity of lithium carbonate is more than or equal to 99.99%) into the pyrolysis base solution, wherein the ratio of the added high-purity 4N-grade lithium carbonate to the pyrolysis base solution is 1g to 1L, namely the addition amount of the high-purity 4N-grade lithium carbonate is 10 g; and controlling the temperature in the pyrolysis container to be 100 ℃, slowly dripping the filtered hydrogenation liquid into the pyrolysis container to pyrolysis capacity, wherein the dripping flow rate of the hydrogenation liquid is 0.25L/min, namely dripping 30L of the hydrogenation liquid to be dripped is completed within 2h, and if the volume of the hydrogenation liquid dripped per minute is 0.625% of the pyrolysis capacity according to the pyrolysis capacity.
Then, reacting for 1 hour at 100 ℃ to obtain pyrolysis liquid, releasing 3/4 volumes of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate with organic alcohol such as absolute ethyl alcohol or absolute methyl alcohol, or glycerol or n-butyl alcohol, filtering, and calcining at 450 ℃ to obtain high-purity lithium carbonate; and the residual pyrolysis liquid in the pyrolysis container is used as pyrolysis base liquid for the next reaction.
(5) Dropwise adding the hydrogenated liquid filtered in the step (3) into the residual pyrolysis liquid in the pyrolysis container in the step (4) at the flow rate of 0.25L/min to the pyrolysis capacity, keeping the temperature for reaction for 1h at 100 ℃ to prepare pyrolysis liquid, releasing 3/4 volumes of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate, and calcining at 450 ℃ to prepare high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is continuously used as pyrolysis base liquid for the next reaction.
(6) And (5) repeating the steps (1) to (5) to continuously produce the high-purity lithium carbonate.
The parameters in the preparation process and the purity of the high-purity lithium carbonate prepared by the steps are shown in table 4, wherein the purification times are the times of the industrial-grade lithium carbonate raw material passing through the purification processes in the steps (1) to (6), the purity of the lithium carbonate is calculated according to a method specified in the industrial standard compilation of high-purity lithium carbonate (2019 review), and the impurity measurement is performed according to GB/T11064.16-2013.
Figure DEST_PATH_IMAGE005
As can be seen from Table 3, after the industrial-grade lithium carbonates with different purities are repeatedly purified by the method, the purities of the prepared lithium carbonates are all higher than 99.99%, which is higher than the standard that the purity of the lithium carbonate is 99.99% specified in YS/T546-2008 in the color industry.

Claims (9)

1. A method for continuously producing high-purity lithium carbonate is characterized by comprising the following steps:
(1) uniformly mixing industrial-grade lithium carbonate and water according to the proportion of 1g (18-25) mL to prepare a slurry;
(2) equally dividing the slurry into a plurality of hydrogenation towers which are connected in series; continuously introducing high-purity CO into the hydrogenation towers connected in series from the bottoms of the two hydrogenation towers arranged at two ends respectively2Hydrogenating to obtain hydrogenated liquid;
(3) filtering the obtained hydrogenated liquid to remove insoluble impurities;
(4) adding the hydrogenated liquid filtered in the step (3) into a pyrolysis container to serve as pyrolysis base liquid, wherein the volume of the pyrolysis base liquid is 1/4-1/3 of the pyrolysis capacity of the pyrolysis container; adding high-purity 4N-grade lithium carbonate into the pyrolysis base solution, controlling the temperature in a pyrolysis container to be 98-100 ℃, dropwise adding the filtered hydrogenation solution into the pyrolysis container to pyrolysis capacity, carrying out heat preservation reaction at the temperature of 98-100 ℃ for 0.5-1 h to prepare pyrolysis solution, releasing 2/3-3/4 volume of pyrolysis solution, filtering, collecting precipitate, washing the precipitate, and calcining at the temperature of 450 ℃ to prepare high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is used as pyrolysis base liquid for the next reaction;
(5) dropwise adding the hydrogenated liquid filtered in the step (3) into the residual pyrolysis liquid in the pyrolysis container in the step (4) to pyrolysis capacity, carrying out heat preservation reaction for 0.5-1 h at the temperature of 98-100 ℃ to prepare pyrolysis liquid, releasing 2/3-3/4 volume of pyrolysis liquid, filtering, collecting precipitate, washing the precipitate, and calcining at the temperature of 450 ℃ to prepare high-purity lithium carbonate; the residual pyrolysis liquid in the pyrolysis container is continuously used as pyrolysis base liquid for the next reaction;
(6) and (5) repeating the steps (1) to (5) to continuously produce the high-purity lithium carbonate.
2. The continuous production method of high-purity lithium carbonate according to claim 1, wherein the CO in the step (2)2The introduction rate of the catalyst is based on the volume of the slurry liquid in the hydrogenation tower connected with the catalyst, and each liter of the slurry liquid corresponds to CO2The feeding rate of (2) is 0.1 to 0.8L/min.
3. The method for continuously producing high-purity lithium carbonate according to claim 2, wherein the CO is corresponding to each liter of slurry2The feeding rate of (2) is 0.2 to 0.6L/min.
4. The method for continuously producing high-purity lithium carbonate according to any one of claims 1 to 3, wherein in the process of slowly adding the filtered hydrogenation solution dropwise into the pyrolysis container in the step (4) and the step (5), the volume of the hydrogenation solution dropwise added per minute is 0.5% to 2% of the pyrolysis capacity.
5. The continuous production method of high-purity lithium carbonate according to claim 4, wherein the high-purity 4N grade lithium carbonate in the step (4) is mixed with the pyrolysis base solution according to the proportion of (1-2) g: 1L.
6. The method for continuously producing high-purity lithium carbonate according to claim 5, wherein the ratio of the industrial-grade lithium carbonate to the water in the step (1) is 1g (20-23) mL.
7. The method for continuously producing high-purity lithium carbonate according to claim 6, wherein the number of the hydrogenation towers connected in series in the step (2) is 3-10.
8. The method for continuously producing high-purity lithium carbonate according to claim 7, wherein the number of the hydrogenation towers connected in series is 4-6.
9. The continuous production method of high-purity lithium carbonate according to claim 8, wherein the filter used for the filtration in the step (3) has a filter pore size of 0.1-1 μm.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114477245A (en) * 2022-02-24 2022-05-13 宁夏天霖新材料科技有限公司 Method for preparing lithium carbonate of battery by continuously carbonizing industrial-grade lithium carbonate
CN115893454A (en) * 2022-11-01 2023-04-04 甘肃睿思科新材料有限公司 Method for efficiently producing ultrapure lithium carbonate with uniform and stable particle size

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CN103833053A (en) * 2014-01-21 2014-06-04 四川天齐锂业股份有限公司 Method of preparing high-purity lithium carbonate of the 5 N grade
CN109942009A (en) * 2019-04-26 2019-06-28 核工业北京化工冶金研究院 A kind of preparation method of battery-level lithium carbonate

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CN103833053A (en) * 2014-01-21 2014-06-04 四川天齐锂业股份有限公司 Method of preparing high-purity lithium carbonate of the 5 N grade
CN109942009A (en) * 2019-04-26 2019-06-28 核工业北京化工冶金研究院 A kind of preparation method of battery-level lithium carbonate

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114477245A (en) * 2022-02-24 2022-05-13 宁夏天霖新材料科技有限公司 Method for preparing lithium carbonate of battery by continuously carbonizing industrial-grade lithium carbonate
CN115893454A (en) * 2022-11-01 2023-04-04 甘肃睿思科新材料有限公司 Method for efficiently producing ultrapure lithium carbonate with uniform and stable particle size

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