Lithium metatitanate type lithium ion sieve precursor preparation device and preparation process method
Through dry mixing processes and equipment, uniform mixing between lithium source and titanium source is achieved, and calcined solid phase synthesis is solved, and the problems of uneven mixing and high energy consumption in traditional processes are achieved, and an efficient and energy-saving preparation process is achieved.
Patent Information
- Application Number
- CN202411770105.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-02-25
AI Technical Summary
In the traditional lithium titanate preparation process, it is difficult to achieve uniformity between the wet mixing of lithium source and titanium source, resulting in complex processes, high energy consumption and high cost.
Using dry mixing process and equipment, uniform mixing between the lithium source and the titanium source is achieved through primary and secondary mixing equipment, and then synthesis is performed by calcining solid phase to obtain the optimal layered structure.
The same uniform effect as wet mixing is achieved, the preparation process is shortened, energy consumption is saved by about 40%, and production costs are reduced.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of lithium resources and relates to a lithium metatitanate type lithium ion sieve precursor preparation device and a preparation process method. Background Art
[0002] With the rapid development of new energy vehicles and new storage industries around the world, the supply of lithium resources has been in a tight situation. Traditional ore extraction of lithium is limited by cost and the total amount of resources, which makes it difficult to effectively solve the contradiction between supply and demand. However, lithium reserves in salt lake brine account for 69% of the world's terrestrial lithium reserves. Salt lake brine has the advantages of rich lithium reserves, high lithium ion concentration, and simple mining process, making it a hot spot in the current production and research of lithium salts. After years of technological development and production practice, lithium extraction from salt lake brine has been achieved through a variety of methods, such as solvent extraction, precipitation, membrane separation, calcination leaching, and adsorption. And adsorption + membrane method has become the mainstream process technology for lithium extraction from salt lakes due to its cost-effectiveness and environmentally friendly advantages. In this technology, high-performance adsorbents are the key to efficient lithium extraction.
[0003] The efficient adsorbents for lithium extraction from salt lakes are mainly ion sieve-type inorganic substances, including titanium, aluminum, and manganese. Among them, titanium-based lithium ion sieves are favored by carbonate-based salt lake lithium resource miners because of their high adsorption capacity, excellent acid and dissolution resistance, and the ability to be used in alkaline salt lakes. The functional component of titanium-based ion sieves is layered lithium metatitanate, and the main synthesis method is to uniformly mix the lithium source and the titanium source in a medium, dry, calcine, crush, shape, activate and other processes. Among them, the uniform mixing of the lithium source and the titanium source and the solid-phase synthesis calcination are the key to ensuring the optimal layered structure.
[0004] The raw materials lithium source and titanium source used to prepare lithium metatitanate have high specific surface energy, and it is difficult for general equipment to mix them evenly. In the current traditional lithium metatitanate preparation process, in order to achieve uniform mixing of multiple components, a dispersion medium is introduced to prepare a wet slurry. Although it is beneficial to mixing uniformity, it also adds the process of medium removal, greatly increasing the process time and complexity, further leading to increased energy consumption and high production costs. According to incomplete statistics, if water is used as a dispersion medium, the energy cost of water evaporation accounts for about 30-40% of the overall preparation energy cost. In view of the fact that the traditional process route meets the performance requirements well, but the process is complicated and does not have economic advantages, it is imperative to develop a simple and energy-saving mixing and dispersion technology. Summary of the invention
[0005] The present invention aims at the problems of the prior art and the drawbacks of the current complex preparation process, high energy consumption and high cost. The present invention provides a lithium metatitanate type lithium ion sieve precursor preparation device and preparation process method, a simple synthesis process method and equipment. The lithium source and the titanium source can be mixed in a dry state by using the mixing process and equipment to achieve uniform mixing of two or more components, achieving the uniformity of wet mixing, and obtaining the optimal layered structure through calcination solid phase synthesis, thereby shortening the preparation process of the titanium-based lithium ion sieve, saving energy consumption, and reducing production costs. A lithium metatitanate type lithium ion sieve precursor preparation process method and equipment are provided.
[0006] A lithium metatitanate type lithium ion sieve precursor preparation device comprises a material storage bin, a primary mixing device, a secondary mixing device, a continuous calcining device and a mechanical crushing device connected by pipelines, the bin has the function of continuous accurate weighing and accurate conveying and metering, the primary mixing device is any one of a high-speed mixer and a plowshare mixer with high-speed shearing, the inner wall of the equipment is lined with wear-resistant ceramic or coated with tungsten carbide, the equipment is provided with a refrigerant cooling jacket, the low-speed mixer for mixing lithium source and titanium source is any one of a paddle mixer and a ribbon mixer, the calcining device for solid phase synthesis is a continuous single-layer or double-layer roller kiln and a push plate kiln, and the equipment for material crushing is a continuous mechanical or air flow crushing device with a grading function.
[0007] A preparation process of a lithium metatitanate type lithium ion sieve precursor comprises the following steps: adding a lithium source and a titanium source with a certain particle size requirement to a mixing device according to a set ratio in an automatic metering device, uniformly mixing them at high speed in a primary mixing device, and then mixing them at low speed in a secondary mixing device; the uniformly mixed materials are transferred to a sagger of a calcining furnace through an automatic metering device; and react to generate lithium metatitanate under calcination with a set heating and insulation curve; the reacted materials are crushed into the required particle size by a mechanical crushing device and then packaged to obtain a stable adsorbent product.
[0008] The advantages of the present invention are: in view of the problem that the lithium source and titanium source can only be mixed evenly by wet mixing in the traditional process, through process and equipment optimization, the same mixing effect as wet mixing is achieved in dry mixing, which greatly saves energy consumption by about 40%.
[0009] The preparation process and equipment provided by the present invention are more energy-saving and efficient, and are convenient for industrial continuous production.
[0010] The traditional preparation process uses a wet method in a liquid medium to effectively overcome the problem that the lithium source and titanium source have high surface energy and are difficult to disperse and mix evenly. However, the introduction of the medium virtually adds the process of medium removal, making the synthesis process complicated, the process section extended, and the energy consumption and preparation cost increased. According to incomplete statistics, if water is used as a dispersion medium, the energy consumption cost of water evaporation accounts for about 30-40% of the overall preparation energy consumption cost. In view of the fact that the traditional process route meets the performance requirements well, but does not have economic advantages, it is imperative to develop a more energy-saving mixing and dispersion technology.
[0011] The present invention aims to introduce a dispersion medium into the current lithium titanate preparation process to achieve uniform mixing of multiple components, which is beneficial to mixing uniformity, but prolongs the process route, greatly increases the process time and complexity, further leads to increased energy consumption and high production costs.
[0012] A simple synthesis process method and equipment, lithium source and titanium source can be mixed in a dry state using the mixing process and equipment to achieve uniform mixing of two or more components, reaching the uniformity of wet mixing, and the optimal layered structure is obtained through calcination solid phase synthesis, shortening the preparation process of titanium-based lithium ion sieves, saving energy consumption, and reducing production costs.
[0013] A process technology and equipment that can evenly mix lithium source, titanium source and additives added according to formula requirements in a dry state, greatly reduces the energy consumption required for production while ensuring product performance, simplifies the production process, and is more energy-efficient and efficient.
[0014] The dry mixing method of the present invention can achieve uniform mixing of two or more components, including adding a small dose of additives at a ratio of about 1:400 to achieve uniform mixing, and the mixing result is equivalent to the wet mixing result of the comparative example.
[0015] By comparing the application performance of the samples of the embodiments and comparative embodiments, it can be seen that the adsorption capacity and selectivity are similar and there is no obvious difference. It can be judged that the dry mixing provided by the present invention can achieve the mixing uniformity of wet mixing. In addition, the comprehensive energy consumption of the dry mixing and wet mixing production lines was measured and calculated. The comprehensive energy consumption of dry mixing is significantly lower than that of wet mixing, with a reduction of about 40%. This reduction is mainly reflected in the elimination of the evaporation energy consumption link of the high specific heat capacity medium in wet mixing. Therefore, the present invention has significant economic value.
[0016] The dry method can achieve the same mixing effect as the wet method, and the powder prepared by the dry method after calcination and crushing has technical indicators such as adsorption capacity and selectivity that are equivalent to those of the wet method. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. As shown in the figure:
[0018] Figure 1 It is a process flow chart of the present invention.
[0019] Figure 2 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION
[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] Example 1: Figure 1 , Figure 2 As shown, a process for preparing a lithium metatitanate type lithium ion sieve precursor is provided, wherein a lithium source and a titanium source with certain particle size requirements are added to a mixing device according to a set ratio in an automatic metering device, and are uniformly mixed at high speed by a primary mixing device, and then mixed at low speed by a secondary mixing device. The uniformly mixed material is transferred to a sagger of a calcining furnace through an automatic metering device, and reacts to generate lithium metatitanate under calcination with a set heating and insulation curve. The reacted material is crushed into the required particle size by a mechanical crushing device and then packaged to obtain a stable adsorbent product.
[0022] A device for preparing a lithium metatitanate type lithium ion sieve precursor comprises a storage bin weighing module 1, a first raw material storage bin 2, a storage bin continuous feeding device 3, a second raw material storage bin 4, a third raw material storage bin 5, a primary mixing device 6, a first mixed material storage bin 7, a second mixed material storage bin 8, a secondary mixing device 9, a calcining device 10, a crushing feeding device 11, and a mechanical crushing device 12.
[0023] There are storage bin continuous feeding devices 3 above the primary mixing device 6, which are connected to the first raw material storage bin 2, the second raw material storage bin 4 and the third raw material storage bin 5, the first raw material storage bin 2 is connected to the storage bin weighing module 1, the second raw material storage bin 4 and the third raw material storage bin 5 are respectively connected to the storage bin weighing module, the primary mixing device 6 is respectively connected to the first mixed material storage bin 7 and the second mixed material storage bin 8 through the crushing feeding device 11, the first mixed material storage bin 7 and the second mixed material storage bin 8 are respectively connected to the mixed material storage bin weighing module, the output port of the first mixed material storage bin 7 and the second mixed material storage bin 8 is connected to the secondary mixing device 9, the output port of the secondary mixing device 9 is connected above one end of the calcining device 10, the pipeline of the crushing feeding device 11 is connected above the other end of the calcining device 10, and the crushing feeding device 11 is connected to the mechanical crushing device 12 through a pipeline.
[0024] The mechanical crushing device 12 and the secondary mixing device 9 are respectively provided with motor devices.
[0025] The lithium source, titanium source and additive storage tanks are connected to the primary mixing device through a metering conveying device and a pipeline. According to the formula amount, the materials to be mixed are intermittently added to the primary mixing device for mixing. After the mixing is completed, the materials are conveyed to the storage bin in front of the secondary mixing device by gravity through the discharge valve and the pipeline. The storage bins are used in a backup manner. When the material in the storage bin meets the amount of the secondary mixing device, the material is conveyed to the secondary mixing device through a pipeline by a spiral feeding device for secondary mixing. After the secondary mixing is completed, the materials are discharged into a temporary storage tank before calcination. The materials in the temporary storage tank are conveyed by airflow to the quantitative feeding module of the calcination device, and are continuously conveyed to the calcination device for heating and heat preservation calcination reaction after quantitative metering into the sagger. After the reaction is completed, the materials are conveyed from the temporary storage tank after calcination to the crushing device through airflow. After the crushing is completed, the required finished product is obtained.
[0026] Example 2: Figure 1 , Figure 2 As shown, a process for preparing a lithium metatitanate type lithium ion sieve precursor comprises the following steps:
[0027] Step 1, accurately weighing the lithium source, titanium source and additives according to the formula amount and adding them into the primary mixing device, and transferring the materials uniformly mixed by the primary high-speed intermittent mixing under cooling water to the secondary mixing;
[0028] Step 2: The materials transferred to the secondary mixing are mixed in the secondary low-speed continuous mixing device;
[0029] Step 3: The materials after the second mixing are transported to the calcining equipment for solid phase reaction;
[0030] Step 4, the calcined material is mechanically crushed and then set aside;
[0031] In the preparation process of lithium metatitanate, the lithium source is one or a mixture of lithium carbonate, lithium hydroxide, lithium citrate, and lithium acetate, and the particle size D90 is less than 60 μm; the selection of the lithium source depends on the market supply, and the purity and impurity content meet the preparation requirements. When lithium hydroxide is used as the lithium source, the ambient humidity is controlled during the feeding amount metering process. In the process of the present invention, the particle size of the lithium source will affect the mixing effect to a certain extent, so the physical state of the lithium source is required to be powdered, and the particle size D90 is less than 60 μm; granular raw materials are not applicable.
[0032] In the preparation process of lithium titanate, the titanium source is titanium dioxide, titanic acid or a mixture of the two. In the process of the present invention, the particle size of the titanium source will also affect the mixing effect to a certain extent. Therefore, the physical state of the lithium source is required to be powdery, with a particle size D90<50μm.
[0033] The preparation process of lithium titanate is affected by the specific application environment and specific performance requirements, such as the requirements for high adsorption capacity, high selectivity, and long-term effectiveness. Therefore, a certain amount of modifier is added in the design of some lithium titanate formulas. The modifier is mostly one or more metal oxides and salts thereof, with a particle size D90<50μm.
[0034] In the preparation process of lithium metatitanate, the lithium source and the titanium source are fed in an automatic manner and the feeding ratio is controlled by a weighing metering device; the fixed molar ratio of the raw materials is accurately controlled to ensure uniform mixing during addition and to perform a solid phase reaction to form an optimal layered structure.
[0035] Due to the high surface energy, easy agglomeration and poor fluidity of lithium source and titanium source, it is difficult to mix multiple components evenly by conventional mixing methods. Therefore, conventional methods use dispersants in media such as water and ethanol to disperse and mix to achieve the purpose of uniform mixing, but it introduces the problem of high energy consumption of medium evaporation. Through the study of dispersion principles and the selection of dispersion equipment, through the preferred mixing process and equipment, the goal of uniform mixing of multiple components in a dry state can also be achieved. In high-speed mixing equipment, the preferred mixing process is: mixing speed is 600-1000rpm, mixing time is 10-30min, the mixing process is completed under refrigerant cooling, and the inner wall of the high-speed mixing equipment needs to be coated with wear-resistant ceramic or tungsten carbide.
[0036] In the preparation process of lithium titanate, the materials after the primary mixing are transferred to the low-speed mixing equipment for secondary mixing, the mixing speed is 40-80rpm, and the mixing residence time is 30-60min; and the processing capacity ratio of the primary high-speed mixing and the secondary low-speed mixing is preferably 1:10-1:30; in the high-speed mixing process, the high-speed shearing of the equipment's dispersing blades enables the multi-component materials to greatly realize the convection movement between each other, thereby achieving the purpose of uniform mixing. However, for high-speed shear mixing, the volume of the equipment and the single batch processing volume will be subject to certain restrictions. The macroscopic uniformity of multiple batches of mixed samples still has certain fluctuations, which is not conducive to stable batch production. Therefore, the stability between batches is improved through the secondary mixing low-speed convection shearing, thereby improving the stable mixing effect, and laying a solid foundation for the performance stability of the calcined product.
[0037] In the preparation process of lithium metatitanate, the mixed materials are transported to the calcination equipment for calcination, and the calcination is carried out according to the following contents, namely: the calcination temperature is preferably 700-850°C; the temperature accuracy of the kiln cross section is preferably ±5°C, the calcination temperature provides energy for the solid phase synthesis process, and the temperature accuracy ensures the uniformity of the material reaction during the process operation; the kiln residence time is preferably 8-15h; the time ratio of heating, insulation and cooling is preferably 0.8-1:1-1.2:1-1.2, so as to ensure that the heating curve can meet the stable implementation of the solid phase synthesis reaction and the perfect development of the crystal structure; the stacking thickness of the material in the calcination equipment is preferably 6-12cm. Too low stacking thickness will affect production capacity and increase production costs, while too high thickness will cause poor solid phase synthesis uniformity due to the influence of heat conduction, so 6-12cm is preferred.
[0038] In the preparation process of lithium metatitanate, the calcined titanium ion sieve precursor is mechanically crushed to obtain a semi-finished product to be formed, and the crushed particle size is preferably such that it does not affect the performance and can meet the forming requirements.
[0039] Example 3: Figure 1 , Figure 2 As shown, a preparation process method of a lithium metatitanate type lithium ion sieve precursor and a preparation process equipment of a lithium metatitanate type lithium ion sieve precursor are mainly composed of a storage bin, a primary mixing device, a secondary mixing device, a calcination reaction device and a mechanical crushing device, and each device is connected by a pipeline.
[0040] The number of storage bins is set according to the formula type, ranging from 2 to 4. The storage bin is equipped with a precise continuous weighing module and a continuous automatic feeding system. Through the system interlocking control, accurate weighing of each component material and quantitative automatic stop can be achieved.
[0041] The primary mixing device is a vertical high-speed mixer and a horizontal plowshare mixer with a flying blade structure. The primary mixing device is directly connected to the storage bin, and the material is directly fed into the mixing device according to the formula amount. After the feeding is completed, the mixing device is sheared at high speed to make the powder materials of each component scattered, atomized, and violently convected, so as to achieve the purpose of uniform mixing. The inner wall of the mixing device is lined with wear-resistant ceramic or coated with tungsten carbide.
[0042] After the primary mixing device finishes mixing, the material is transferred to the primary mixing material storage bin through the outlet pneumatic valve. The configuration of the primary mixing material storage bin is the same as that of the raw material storage bin, equipped with precise continuous weighing device and automatic feeding device. The primary mixing material bin is configured as one standby and one for use.
[0043] The secondary mixing device is a horizontal single-shaft paddle mixer or a horizontal twin-screw mixer. The storage capacity of the mixer is 10-30 times that of the primary mixer. The mixer can realize continuous feeding and discharging, which can ensure the continuity of production and the uniformity of batch mixing.
[0044] The calcining device is a roller kiln or a push-plate kiln. The gap in the furnace is suitable for stacking double-layer saggers. The kiln has the functions of automatic loading, automatic unloading and conveying, and has excellent temperature control accuracy and operating speed adjustment capabilities.
[0045] The pulverizing device is a mechanical pulverizing device or an air flow pulverizing device, and the pulverizing device is equipped with automatic classification dust collection facilities to facilitate the regulation of particle size and prevent dust pollution.
[0046] Example 4: Figure 1 , Figure 2 As shown, a lithium metatitanate type lithium ion sieve precursor preparation process method, from a storage bin containing a lithium source (lithium carbonate battery grade purity> 99.5% particle size: D90<50μm) quantitatively adds 85kg of lithium source to a primary mixer, and from a storage bin containing a titanium source (metatitanate purity> 98% particle size: D90<5μm) quantitatively adds 115kg of titanium source to a primary mixer. After the filling is completed, the primary mixing device is turned on, the mixing speed is 750rpm, the mixing time is 15min, and the material is mixed after the mixing is completed. The materials are transferred to a mixing storage bin for temporary storage, and the first-level mixer continues to feed the next batch of lithium source and titanium source for mixing. When the mixed batches exceed 15 batches, the first mixing storage bin starts to feed the second-level mixer, and the speed of the second-level mixer is set to 60rpm. The position of the discharge port is adjusted to ensure that the residence time of the material in the second-level mixer is 60min. The discharged materials are transported by airflow to the roller kiln feeding device, and after quantitative measurement of 3kg, they are added to the calcining sagger, calcined using the calcination process, and then crushed by the crushing equipment for use.
[0047] Example 5: Figure 1 , Figure 2As shown, a lithium metatitanate type lithium ion sieve precursor preparation process method, 97kg lithium source is quantitatively added to the primary mixer from a storage bin containing a lithium source (lithium carbonate battery grade purity> 99.5% particle size: D90<50μm), 102.5kg titanium source is quantitatively added to the primary mixer from a storage bin containing a titanium source (titanium dioxide purity> 99% particle size: D90<20μm), and 0.5kg additive is quantitatively added to the primary mixer from a storage bin containing an additive (zirconia purity> 99% particle size: D90<50μm). After the filling is completed, the primary mixing device is turned on and the mixer is mixed. The total speed is 800rpm, and the mixing time is 20min. After the mixing is completed, the materials are transferred to a mixing storage bin for temporary storage, and the first-level mixer continues to feed the next batch of lithium source and titanium source for mixing. When the mixing batch exceeds 20 batches, the first mixing storage bin starts to feed the second-level mixer, and the set speed of the second-level mixer is 65rpm; the position of the discharge port is adjusted to ensure that the residence time of the material in the second-level mixer is 60min; the discharged material is transported by airflow to the roller kiln feeding device, and after quantitative measurement of 3kg, it is added to the calcining sagger, and calcined using a controlled calcination process, and then crushed by a crushing equipment for standby use.
[0048] Example 6: Figure 1 , Figure 2 As shown, a lithium metatitanate type lithium ion sieve precursor preparation process method, from a storage bin containing a lithium source (monohydrate lithium hydroxide battery-grade lithium hydroxide content> 57% particle size: D90<60μm) quantitatively adds 100.5kg of lithium source to a primary mixer, from a storage bin containing a titanium source (titanium dioxide purity> 99% particle size: D90<20μm) quantitatively adds 98.5kg of titanium source to the primary mixer, from a storage bin containing an additive (zirconia purity> 99% particle size: D90<50μm) quantitatively adds 1.0kg of additive to the primary mixer, after the filling is completed, the primary mixer is turned on. The device has a mixing speed of 850rpm and a mixing time of 20min. After the mixing is completed, the materials are transferred to a mixing storage bin for temporary storage, and the first-level mixer continues to feed the next batch of lithium source and titanium source for mixing. When the mixing batch exceeds 18 batches, the first mixing storage bin starts to feed the second-level mixer, and the setting speed of the second-level mixer is 75rpm; the position of the discharge port is adjusted to ensure that the residence time of the material in the second-level mixer is 55min; the discharged material is transported by air flow to the roller kiln feeding device, and after quantitative measurement of 3kg, it is added to the calcining sagger, calcined by the calcination process, and then crushed by the crushing equipment for use.
[0049] Comparative Example 4:
[0050] 1800kg of deionized water is added to the mixing kettle from the deionized water station, 30kg of dispersant is added to the mixing kettle from the dispersant storage tank, 510kg of lithium source is quantitatively added to the mixing kettle from the storage bin containing lithium source (lithium carbonate battery grade purity>99.5% particle size: D90<20μm), and 690kg of titanium source is quantitatively added to the mixing kettle from the storage bin containing titanium source (metatitanic acid purity>98% particle size: D90<5μm). After the filling is completed, the mixing kettle stirring device is turned on, the mixing speed is 70rpm, and the mixing time is 50min. After the mixing is completed, the slurry is transferred to the sand mill for sand grinding. The sand-milled slurry is transferred to the spray drying tower for spray drying. The material after spray drying is transported to the roller kiln feeding device by airflow, and after quantitative 3kg is measured, it is added to the calcination sagger, calcined by the calcination process, and then crushed by the crushing equipment for use.
[0051] Comparative Example 5:
[0052] 1800kg of deionized water is added to the mixing kettle from the deionized water station, 30kg of dispersant is added to the mixing kettle from the dispersant storage tank, 582kg of lithium source is quantitatively added to the mixing kettle from the storage bin containing lithium source (lithium carbonate battery grade purity>99.5% particle size: D90<20μm), 615kg of titanium source is quantitatively added to the mixing kettle from the storage bin containing titanium source (titanium dioxide purity>99% particle size: D90<20μm), and 1000kg of titanium source is quantitatively added to the mixing kettle from the storage bin containing additives (zirconia purity>99% particle size: D90 <50μm) storage bin quantitatively adds 4kg of additives to the mixing kettle. After the filling is completed, the mixing kettle stirring device is turned on, the mixing speed is 80rpm, and the mixing time is 60min. After the mixing is completed, the slurry is transferred to the sand mill for sand grinding. The sand-milled slurry is transferred to the spray drying tower for spray drying. The material discharged from the spray drying is transported by air flow to the roller kiln feeding device. After quantitative measurement of 3kg, it is added to the calcining sagger and calcined by the calcining process. It is then crushed by the crushing equipment and set aside.
[0053] Table 1:
[0054]
[0055]
[0056] As shown in Table 1, the mixing uniformity of the embodiments and comparative embodiments, the adsorption selectivity of the prepared products, and the energy consumption during the production process were tracked and tested, and the test results are shown in the table above. It can be seen from the data in the table that the dry mixing method of the present invention can achieve uniform mixing of two or more components, including adding a ratio of about 1:400 and a small dose of additives can also achieve uniform mixing, and the mixing result is equivalent to the wet mixing result of the comparative example. By comparing the application performance of the samples of the embodiments and comparative examples, their adsorption capacity and selectivity are similar, with no obvious difference. It can be judged that the dry mixing provided by the present invention can achieve the mixing uniformity of wet mixing. In addition, the comprehensive energy consumption of the production lines of dry mixing and wet mixing was calculated. The comprehensive energy consumption of dry mixing is significantly lower than that of wet mixing, with a reduction of about 40%. The reduction is mainly reflected in the elimination of the evaporation energy consumption link of the high specific heat capacity medium in wet mixing. Therefore, the present invention has significant economic value.
[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A process for preparing a lithium metatitanate type lithium ion sieve precursor, characterized in that: The lithium source and the titanium source are added to the mixing device in an automatic metering device according to the set ratio, that is, the lithium-titanium molar ratio is between 1.8 and 2.
1. After being uniformly mixed at high speed by the first-level mixing device, they are mixed at low speed by the second-level mixing device. The uniformly mixed materials are transferred to the sagger of the calcining furnace through the automatic metering device. Under the calcination according to the set heating and insulation curve, lithium metatitanate is generated by reaction. The reacted materials are crushed into the required particle size by a mechanical crushing device and then packaged to obtain a stable adsorbent product.
2. The method for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 1, characterized in that: The following steps are involved: Step 1: Add lithium source, titanium source and additives according to the formula, the lithium-titanium molar ratio is between 1.8-2.1, and the additive addition amount is 0-2%. After metering, add them to the first-stage mixing device. Under cooling water, the materials that are uniformly mixed by the first-stage high-speed intermittent mixing are transferred to the second-stage mixing. Step 2: The materials transferred to the secondary mixing are mixed in the secondary low-speed continuous mixing device. Step 3: The materials after the second mixing are transported to the calcining equipment for solid phase reaction. Step 4: The calcined material is crushed mechanically for later use.
3. The method for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 2, characterized in that: The particle size of lithium source is D90<60μm; the particle size of titanium source is D90<50μm; the particle size of added modifier is D90<50μm. The measured lithium source and titanium source are mixed in a high-speed mixing device at a mixing speed of 600-1000rpm and a mixing time of 10-30min. The mixing process is completed under cooling by a refrigerant.
4. The method for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 2, characterized in that: The materials after primary mixing are transferred to a low-speed mixing device for secondary mixing. The mixing speed is 40-80 rpm and the mixing residence time is 30-60 min.
5. The method for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 2, characterized in that: The processing capacity ratio of the first-stage high-speed mixing and the second-stage low-speed mixing is 1:10-1:
30.
6. The method for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 2, characterized in that: A mixture of one or more of lithium carbonate, lithium hydroxide, lithium citrate, and lithium acetate containing lithium sources is quantitatively added to the primary mixer with a particle size of D90 < 50 μm. A storage bin containing metatitanic acid and titanium dioxide containing titanium sources, with a purity of > 98% and a particle size of D90 < 5 μm, is quantitatively added to the primary mixer with 115 kg of titanium source. After the filling is completed, the primary mixer is turned on, the mixing speed is 750 rpm, the mixing time is 15 minutes, and after the mixing is completed, the materials are transferred to a The mixing storage bin is temporarily stored, and the first-level mixer continues to feed the next batch of lithium source and titanium source for mixing. When the mixed batch exceeds 15 batches, the first mixing storage bin starts to feed into the second-level mixer, and the setting speed of the second-level mixer is 60rpm; the position of the discharge port is adjusted to ensure that the residence time of the material in the second-level mixer is 60min; the discharged material is transported by air flow to the roller kiln feeding device, and after quantitative measurement of 3kg, it is added into the calcining sagger, calcined by the calcination process, and then crushed by the crushing equipment for use.
7. A lithium metatitanate type lithium ion sieve precursor preparation device, characterized in that: It includes material storage silos, primary mixing equipment, secondary mixing equipment, continuous calcining equipment and mechanical crushing equipment connected by pipelines. The silos have the functions of continuous accurate weighing, precise conveying and metering. The primary mixing equipment is any one of a high-speed mixer and a plowshare mixer with high-speed shearing. The inner wall of the equipment is lined with wear-resistant ceramics or coated with tungsten carbide. The equipment is equipped with a refrigerant cooling jacket. The low-speed mixer for mixing lithium source and titanium source is any one of a paddle mixer and a ribbon mixer. The calcination equipment used for solid phase synthesis is a continuous single-layer or double-layer roller kiln and push plate kiln. The equipment used for material crushing is a continuous mechanical or air flow crushing device with a grading function.
8. The device for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 7, characterized in that: There are storage bin continuous feeding devices above the primary mixing device, which are connected to the first raw material storage bin, the second raw material storage bin and the third raw material storage bin, the first raw material storage bin is connected to the storage bin weighing module, the second raw material storage bin and the third raw material storage bin are respectively connected to the storage bin weighing module, the primary mixing device is connected to the first mixed material storage bin and the second mixed material storage bin respectively through the crushing feeding device, the first mixed material storage bin and the second mixed material storage bin are respectively connected to the mixed material storage bin weighing module, the output port of the first mixed material storage bin and the second mixed material storage bin is connected to the secondary mixing device, the output port of the secondary mixing device is connected above one end of the calcining device, the pipeline of the crushing feeding device is connected above the other end of the calcining device, and the crushing feeding device is connected to the mechanical crushing device through a pipeline.
9. The device for preparing a lithium metatitanate type lithium ion sieve precursor according to claim 7 is characterized in that: The mechanical crushing device and the two-stage mixing device are respectively provided with motor devices.