CN117800368A - Method for preparing battery-grade lithium hydroxide monohydrate from low-grade lithium carbonate - Google Patents
Method for preparing battery-grade lithium hydroxide monohydrate from low-grade lithium carbonate Download PDFInfo
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- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 title claims abstract description 76
- 229910052808 lithium carbonate Inorganic materials 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 68
- PQVSTLUFSYVLTO-UHFFFAOYSA-N ethyl n-ethoxycarbonylcarbamate Chemical compound CCOC(=O)NC(=O)OCC PQVSTLUFSYVLTO-UHFFFAOYSA-N 0.000 title claims abstract description 63
- GLXDVVHUTZTUQK-UHFFFAOYSA-M lithium hydroxide monohydrate Substances [Li+].O.[OH-] GLXDVVHUTZTUQK-UHFFFAOYSA-M 0.000 title claims abstract description 63
- 229940040692 lithium hydroxide monohydrate Drugs 0.000 title claims abstract description 63
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims abstract description 414
- 239000007787 solid Substances 0.000 claims abstract description 53
- 239000003960 organic solvent Substances 0.000 claims abstract description 43
- 238000009993 causticizing Methods 0.000 claims abstract description 40
- 229910052751 metal Inorganic materials 0.000 claims abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 19
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 31
- 238000001035 drying Methods 0.000 claims description 27
- 239000002002 slurry Substances 0.000 claims description 27
- 239000007788 liquid Substances 0.000 claims description 23
- 238000001914 filtration Methods 0.000 claims description 22
- 238000005292 vacuum distillation Methods 0.000 claims description 18
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 16
- 239000000292 calcium oxide Substances 0.000 claims description 16
- 235000012255 calcium oxide Nutrition 0.000 claims description 16
- 239000000706 filtrate Substances 0.000 claims description 16
- 238000000926 separation method Methods 0.000 claims description 16
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 15
- 239000011575 calcium Substances 0.000 claims description 14
- 229910052791 calcium Inorganic materials 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 229910001868 water Inorganic materials 0.000 claims description 14
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 13
- 239000002893 slag Substances 0.000 claims description 13
- 238000005086 pumping Methods 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 10
- 238000002386 leaching Methods 0.000 claims description 9
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 8
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 claims description 8
- 239000002244 precipitate Substances 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 6
- 229910019142 PO4 Inorganic materials 0.000 claims description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 4
- 235000006408 oxalic acid Nutrition 0.000 claims description 4
- 239000010452 phosphate Substances 0.000 claims description 4
- BHZRJJOHZFYXTO-UHFFFAOYSA-L potassium sulfite Chemical compound [K+].[K+].[O-]S([O-])=O BHZRJJOHZFYXTO-UHFFFAOYSA-L 0.000 claims description 4
- 235000019252 potassium sulphite Nutrition 0.000 claims description 4
- 235000010265 sodium sulphite Nutrition 0.000 claims description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 3
- 235000021317 phosphate Nutrition 0.000 claims description 3
- 235000011007 phosphoric acid Nutrition 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 3
- 239000002351 wastewater Substances 0.000 claims description 3
- 238000001354 calcination Methods 0.000 claims description 2
- 239000012535 impurity Substances 0.000 abstract description 24
- 238000004519 manufacturing process Methods 0.000 abstract description 24
- 238000002360 preparation method Methods 0.000 abstract description 13
- 238000002425 crystallisation Methods 0.000 abstract description 7
- 230000008025 crystallization Effects 0.000 abstract description 7
- 239000000243 solution Substances 0.000 description 33
- 238000013461 design Methods 0.000 description 9
- 238000000746 purification Methods 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- CNLWCVNCHLKFHK-UHFFFAOYSA-N aluminum;lithium;dioxido(oxo)silane Chemical compound [Li+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O CNLWCVNCHLKFHK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 229910052629 lepidolite Inorganic materials 0.000 description 1
- 150000002642 lithium compounds Chemical class 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 229910052642 spodumene Inorganic materials 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
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- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention belongs to the technical field of battery-grade lithium hydroxide monohydrate, in particular to a method for preparing battery-grade lithium hydroxide monohydrate by using low-grade lithium carbonate, which aims at the problems of complicated production process and high production cost in the prior art for preparing battery-grade lithium hydroxide monohydrate by using lithium carbonate, and provides the following scheme that the method comprises the following steps: causticizing reaction, preparation of lithium hydroxide solution, preparation of lithium hydroxide solid and treatment of lithium hydroxide solid. The lithium hydroxide solution is crystallized through the insolubility of lithium hydroxide in an organic solvent during the preparation of lithium hydroxide solid, so that the crystallization process is greatly simplified, the lithium hydroxide preparation cost is reduced more conveniently in the lithium hydroxide production process, in addition, the multi-step impurity removal is carried out through causticization reaction, a metal precipitant and the organic solvent, the purity of the lithium hydroxide monohydrate prepared by the low-quality lithium carbonate from different sources meets the requirement of a battery level, and the preparation cost of the lithium hydroxide is greatly reduced.
Description
Technical Field
The invention relates to the technical field of preparation processes of battery-grade lithium hydroxide monohydrate, in particular to a method for preparing battery-grade lithium hydroxide monohydrate by using low-grade lithium carbonate.
Background
As a light metal element of the third and first main groups of the periodic table, lithium plays an indispensable key role in the society of today, and is widely used in the fields of energy storage, battery technology, medical treatment, and the like. Among them, lithium ion batteries have become one of the most representative applications, and have become the first energy storage schemes in the fields of mobile devices, electric vehicles, renewable energy sources, and the like. The characteristics of high energy density, light weight, portability and long service life provide a solid foundation for high-efficiency energy utilization in the modern society. In 2019, lithium hydroxide has become a main growth motive force of lithium compounds due to the rapid development of high-nickel ternary batteries, and the rapid development has triggered a surge in demand for lithium hydroxide supply, so as to promote the lithium industry to continuously explore more efficient production methods and purification technologies. The preparation of battery grade lithium hydroxide monohydrate by using lithium carbonate is a common means in the prior art.
According to the specification of GB/T11075-2013 lithium carbonate, does not accord with Li 2 CO 3 -2 having a major content of not less than 98.5% and an impurity content of not more than Li 2 CO 3 The products of the index required for impurities of-2 can be referred to as low grade lithium carbonate. In the prior art, the main production process of lithium hydroxide monohydrate is a lithium carbonate causticizing method, in the lithium carbonate causticizing method, impurities are removed usually through a process of multi-round concentration crystallization and re-dissolution recrystallization, and in order to ensure the purity of the prepared lithium hydroxide, high-quality industrial grade lithium carbonate is generally adopted for preparing the lithium hydroxide, so that the purity of the prepared lithium hydroxide reaches the battery level.
However, the process steps of the impurity removal technology of multi-round concentration crystallization and re-dissolution recrystallization are complicated, so that the lithium hydroxide production efficiency is lower, the energy consumption is higher, and the production cost of the lithium hydroxide is increased. In addition, the cost for preparing lithium hydroxide by adopting high-quality industrial-grade lithium carbonate is high, the purification step is added in the process of purchasing low-quality lithium carbonate, and the production cost of lithium hydroxide is increased in a phase-change manner.
Disclosure of Invention
Based on the above, the invention aims to provide a method for preparing battery grade lithium hydroxide monohydrate by using lithium carbonate, which solves the problems of complicated production process and high production cost of the battery grade lithium hydroxide monohydrate prepared by using lithium carbonate in the prior art.
The invention provides a method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate, which is characterized by comprising the following steps:
preparing low-quality lithium carbonate, quicklime and water into slurry according to a certain proportion, putting the slurry into a reaction kettle for reaction, and filtering the lithium hydroxide slurry obtained by the reaction after the reaction is finished to obtain causticized liquid and calcium slag;
step two, preparing lithium hydroxide solution, namely adding a preset amount of metal precipitant into the causticizing solution obtained in the step one, and filtering by a filtering device to obtain lithium hydroxide solution;
step three, preparing lithium hydroxide solid, namely pumping the lithium hydroxide solution obtained by filtering in the step two into a crystallizer filled with an organic solvent, stirring and crystallizing, and performing solid-liquid separation on the precipitate to obtain lithium hydroxide solid and filtrate;
and fourthly, treating lithium hydroxide solids, leaching the lithium hydroxide solids obtained by separation in the third step, and drying the leached lithium hydroxide solids through drying equipment to obtain battery-grade lithium hydroxide monohydrate.
According to the method for preparing battery-grade lithium hydroxide by using low-grade lithium carbonate, low-quality lithium carbonate is treated through a causticizing reaction to obtain causticizing solution containing lithium hydroxide, a metal precipitant is added into the causticizing solution to remove impurities from the lithium hydroxide, the solution is filtered and filtered to remove impurities to obtain lithium hydroxide solution, then the lithium hydroxide solution is pumped into a crystallizer to be mixed and stirred with an organic solvent, lithium hydroxide is crystallized to obtain lithium hydroxide solid through insolubility of the lithium hydroxide in the organic solvent, other impurities are dissolved into the organic solvent, further impurity removal and purification of the lithium hydroxide are realized, finally, the lithium hydroxide solid is leached to remove impurities attached to the surface of the lithium hydroxide solid, and drying is carried out to obtain the battery-grade lithium hydroxide. The lithium carbonate with low quality can be used for preparing the battery grade lithium hydroxide monohydrate through a multi-step impurity removal process, so that the production cost of the battery grade lithium hydroxide monohydrate is greatly reduced, and the traditional multiple evaporation crystallization process is not adopted, but the lithium hydroxide is crystallized through the insolubility of the lithium hydroxide in the organic solvent, so that the crystallization process is greatly simplified, and the production cost of the battery grade lithium hydroxide monohydrate is further reduced. In addition, lithium carbonate impurities from different sources are different, and lithium carbonate from different sources is adopted to prepare the battery grade lithium hydroxide monohydrate with high yield through a multi-step impurity removal process, so that the universality of the process method is provided. Therefore, the invention solves the problems of complicated production process and high production cost of the battery grade lithium hydroxide monohydrate prepared by lithium carbonate in the prior art.
In one possible design, the Li of the low quality lithium carbonate 2 CO 3 The content is 70% -98.5%, and the slurry comprises the following components: li (Li) 2 CO 3 CaO=1:1.05-1.5, and the solid-liquid ratio is 1:8-12, wherein the causticizing temperature is 80-95 ℃, and the causticizing time is 1-10 h.
In one possible design, the metal precipitant is one or more of oxalic acid or oxalate, phosphoric acid or phosphate, sodium sulfite and potassium sulfite, and the filtering device adopts a precise filter.
In one possible design, the organic solvent is one or more of methanol, ethanol, and acetone.
In one possible design, the lithium hydroxide solution is pumped into a crystallizer containing an organic solvent while stirring at a rate of 400rpm to 700rpm for a period of 0.5h to 3h.
In one possible design, the ratio of the lithium hydroxide solution pumping amount to the organic solvent is 1:3-6.
In one possible design, the lithium hydroxide solid obtained by the separation in the step three is leached by the organic solvent, and then the leached lithium hydroxide solid is dried by adopting one of drying cylinder type drying equipment, hot air type drying equipment or far infrared type drying equipment, and the water content of the dried lithium hydroxide solid is reduced to below 1%.
In one possible design, the causticizing reaction, preparing low-quality lithium carbonate, quicklime and water into slurry according to a certain proportion, putting the slurry into a reaction kettle for reaction, and filtering the lithium hydroxide slurry obtained by the reaction after the reaction is finished to obtain causticizing solution and calcium slag, wherein the steps of preparing the causticizing solution and the calcium slag include: and filtering the lithium hydroxide slurry through plate-and-frame filter pressing equipment to obtain causticizing liquid and calcium slag, and calcining the calcium slag at high temperature to obtain quicklime to be recycled as a causticizing reaction raw material.
In one possible design, the preparation of the lithium hydroxide solid, pumping the lithium hydroxide solution obtained by filtering in the second step into a crystallizer containing an organic solvent, stirring and crystallizing, and performing solid-liquid separation on the precipitate to obtain the lithium hydroxide solid and a filtrate, wherein the preparation method comprises the following steps of: and (3) carrying out low-temperature distillation or vacuum distillation on the filtrate to recover the organic solvent in the filtrate into the crystallizer, wherein the low-temperature distillation temperature is 40-80 ℃, and the vacuum distillation pressure is-5 Pa-10 Pa.
In one possible design, the step of leaching the lithium hydroxide solid obtained by the separation in the step three, and then drying the leached lithium hydroxide solid by a drying device to obtain battery grade lithium hydroxide monohydrate comprises the following steps: and (3) carrying out low-temperature distillation or vacuum distillation on the wastewater generated by leaching, so that the organic solvent in the filtrate is recycled to the crystallizer.
Drawings
FIG. 1 is a flow chart of a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate according to an embodiment of the present invention;
the invention will be further described in the following detailed description in conjunction with the above-described figures.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
In order to solve the problems of complicated production process and high production cost of preparing battery grade lithium hydroxide by using lithium carbonate in the prior art, the embodiment of the invention redesigns the current preparation process of the battery grade lithium hydroxide, and provides a brand-new method for preparing the battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate, referring to fig. 1, which specifically comprises the following steps:
preparing low-quality lithium carbonate, quicklime and water into slurry according to a certain proportion, putting the slurry into a reaction kettle for reaction, and filtering the lithium hydroxide slurry obtained by the reaction after the reaction is finished to obtain causticized liquid and calcium slag;
step two, preparing lithium hydroxide solution, namely adding a preset amount of metal precipitant into the causticizing solution obtained in the step one, and filtering by a filtering device to obtain lithium hydroxide solution;
step three, preparing lithium hydroxide solid, namely pumping the lithium hydroxide solution obtained by filtering in the step two into a crystallizer filled with an organic solvent, stirring and crystallizing, and performing solid-liquid separation on the precipitate to obtain lithium hydroxide solid and filtrate;
and fourthly, treating lithium hydroxide solids, leaching the lithium hydroxide solids obtained by separation in the third step, and drying the leached lithium hydroxide solids through drying equipment to obtain battery-grade lithium hydroxide monohydrate.
In the first step, li of low-quality lithium carbonate 2 CO 3 The content is 70% -98.5%, and the slurry comprises the following components: li (Li) 2 CO 3 CaO=1:1.05-1.5, the solid-liquid ratio is 1:8-12, the causticizing temperature is 80-95 ℃, the causticizing time is 1-10 h, the lithium hydroxide slurry after the causticizing reaction is filtered by a plate-frame filter pressing device to obtain causticizing liquid and calcium slag, the causticizing liquid is used for a process for preparing lithium hydroxide solution in the second step, and the calcium slag is calcined at high temperature to form quicklime to be recycled as a causticizing reaction raw material. So as to realize the recycling of raw materials and further reduce the production cost. Li in low quality lithium carbonate 2 CO 3 The content of (2) is greater than a certain value to provide enough lithium so that the yield of lithium hydroxide reaches a satisfactory value, and therefore the Li in the low-quality lithium carbonate 2 The content of CO is more than 70 percent.
In the second step, the metal precipitant is one or more of oxalic acid or oxalate, phosphoric acid or phosphate, sodium sulfite and potassium sulfite, and the filter equipment adopts a precise filter. Impurities such as p Ca, mg, fe, cu in the causticizing liquid are removed by reacting the metal precipitant with the impurities. In addition, the reacted solution is filtered by a precise filter, so that the product of the reaction of the metal precipitant and the impurities is removed from the solution, and the impurity removal of the lithium hydroxide solution is completed.
In the third step, the organic solvent is one or more of methanol, ethanol and acetone, the lithium hydroxide solution is pumped into a crystallizer filled with the organic solvent and is stirred at the speed of 400rpm-700rpm for 0.5h-3h, and the ratio of the pumping amount of the lithium hydroxide solution to the organic solvent is 1:3-6. Lithium hydroxide is crystallized by controlling the pumping amount of lithium hydroxide solution and an organic solvent in a crystallizer and by insolubility of lithium hydroxide in the organic solvent, solid-liquid separation is carried out on a precipitate to obtain lithium hydroxide solid and filtrate, then the lithium hydroxide solid is used for processing in the step four, and the filtrate is subjected to low-temperature distillation or vacuum distillation, so that the organic solvent in the filtrate is recycled to the crystallizer, thereby realizing recycling of raw materials and further reducing the production cost. The low-temperature distillation temperature is 40-80 ℃, and the vacuum distillation pressure is-5 Pa-10 Pa.
In the fourth step, the lithium hydroxide solid obtained by the separation in the third step is leached by the organic solvent, and then the leached lithium hydroxide solid is dried by one of drying cylinder type drying equipment, hot air type drying equipment or far infrared type drying equipment, and the water content of the lithium hydroxide solid after the drying is reduced to below 1%. In addition, the waste water generated by leaching is subjected to low-temperature distillation or vacuum distillation, so that the organic solvent in the filtrate is recycled to the crystallizer. So as to realize the recycling of raw materials and further reduce the production cost.
The invention is further illustrated by the following examples:
example 1
The embodiment of the invention provides a method for preparing battery-grade lithium hydroxide monohydrate by using low-grade lithium carbonate, which comprises the following steps:
step one, causticizing reaction, preparing Li extracted from lepidolite 2 CO 3 70% low-quality lithium carbonate, quicklime and water according to Li 2 CO 3 CaO=1:1.1, a slurry is prepared according to the solid-liquid ratio of 1:10, the slurry is put into a reaction kettle for reaction, the causticizing temperature is 85 ℃, the causticizing time is 5 hours, and after the reaction is finished, the lithium hydroxide slurry obtained by the reaction is filtered to obtain causticizing liquid and calcium slag;
step two, preparing lithium hydroxide solution, namely adding a preset amount of metal precipitant into the causticizing solution obtained in the step one, and filtering the solution by a precise filter to obtain lithium hydroxide solution, wherein the metal precipitant is oxalic acid;
step three, preparing lithium hydroxide solid, namely pumping the lithium hydroxide solution obtained by filtering in the step two into a crystallizer filled with an organic solvent, stirring and crystallizing, and then carrying out solid-liquid separation on the precipitate to obtain the lithium hydroxide solid and filtrate, wherein the stirring speed is 550rpm, the stirring time is 2h, the ratio of the pumping amount of the lithium hydroxide solution to the organic solvent is 1:4.5, and the organic solvent is methanol;
and step four, lithium hydroxide solid treatment, namely leaching the lithium hydroxide solid obtained by separation in the step three by using an organic solvent, and drying the leached lithium hydroxide solid by using drying equipment to obtain battery-grade lithium hydroxide monohydrate, wherein the organic solvent is methanol.
Example two
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from example one in that Li 2 CO 3 :CaO＝1:1.05。
Example III
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from example one in that Li 2 CO 3 :CaO＝1:1.5。
Example IV
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from example one in that the solid to liquid ratio in the slurry is 1:8.
Example five
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from example one in that the solid to liquid ratio in the slurry is 1:12.
Example six
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, differing from example one in that the causticizing temperature is 80 ℃.
Example seven
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, differing from example one in that the causticizing temperature is 95 ℃.
Example eight
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, differing from example one in that the causticizing time is 2 hours.
Example nine
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, differing from example one in that the causticizing time is 3 hours.
Examples ten
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, differing from example one in that the causticizing time is 8 hours.
Example eleven
The present embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, which is different from the first embodiment in that the metal precipitant is oxalate.
Example twelve
The present embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, which is different from the first embodiment in that the metal precipitant is phosphoric acid.
Example thirteen
The present embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, which is different from the first embodiment in that the metal precipitant is phosphate.
Examples fourteen
The present embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, which is different from the first embodiment in that the metal precipitant is sodium sulfite.
Example fifteen
The present embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, which is different from the first embodiment in that the metal precipitant is potassium sulfite.
Examples sixteen
The embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate, which is different from the first embodiment in that the organic solvent is ethanol.
Example seventeen
The embodiment also provides a method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate, which is different from the first embodiment in that the organic solvent is acetone.
Example eighteen
The present example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from the first example in that low quality lithium carbonate is extracted from salt lake brine.
Examples nineteenth
This example also provides a method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate, which differs from example one in that the low quality lithium carbonate is extracted from spodumene.
In specific implementation, the battery-grade lithium hydroxide is prepared according to the technological process and technological parameters defined in the first to seventeen examples, and then the lithium hydroxide main content and the lithium hydroxide yield of the single-water battery-grade lithium hydroxide prepared in the first to seventeen examples are measured respectively, and the results are shown in table 1:
TABLE 1
As can be seen from table 1, when preparing lithium hydroxide of a single-water battery grade by the process, different process parameters, such as the ratio of lithium carbonate to calcium oxide, the solid-to-liquid ratio in the slurry, and the temperature and time of the causticization reaction have a larger influence on the yield of lithium hydroxide and a smaller influence on the purity of lithium hydroxide of a single-water battery grade. The metal precipitant is different from the organic solvent, so that the influence on the yield of lithium hydroxide is small, and the influence on the yield and purity of lithium hydroxide of a single-water battery level is large. In addition, the battery grade lithium hydroxide monohydrate with the main content of 56.5-57.5% of lithium hydroxide can be prepared by using the low-quality lithium carbonate by using the process flow and the parameters, namely, the purity of the lithium hydroxide monohydrate reaches 98.98-100%.
In specific implementation, battery grade lithium hydroxide is prepared according to the technological process and technological parameters defined in the first, eighteen and nineteen embodiments, and then lithium hydroxide main content measurement and lithium hydroxide yield measurement are respectively carried out on the lithium hydroxide of the single-water battery grade prepared in the first, eighteen and nineteen embodiments, and the results are shown in table 2:
TABLE 2
As can be seen from table 2, when the lithium hydroxide of the battery grade is prepared by the process, although the lithium carbonate of low quality from different sources contains different impurities, the lithium hydroxide of the battery grade with the main content of 56.5% -57.5% can be prepared by using the low quality lithium carbonate of different sources by using the process flow and the parameters, namely, the purity of the lithium hydroxide of the battery grade reaches 98.98% -100%. Furthermore, the process method provided by the invention has strong universality and wide applicability, and is beneficial to popularization.
The preparation process of the invention comprises the following steps: causticizing reaction, lithium hydroxide solution preparation, lithium hydroxide solid preparation and lithium hydroxide solid treatment;
the lithium hydroxide solution is pumped into a crystallizer to be mixed and stirred with an organic solvent, lithium hydroxide is crystallized to obtain lithium hydroxide solid through the insolubility of the lithium hydroxide in the organic solvent, other impurities are dissolved into the organic solvent, further impurity removal and purification are realized on the lithium hydroxide, finally, the lithium hydroxide solid is leached, the impurities attached to the surface of the lithium hydroxide solid are removed, and drying is carried out, so that the battery-grade lithium hydroxide monohydrate is obtained. The lithium carbonate with low quality can be used for preparing the battery grade lithium hydroxide monohydrate through a multi-step impurity removal process, so that the production cost of the battery grade lithium hydroxide monohydrate is greatly reduced, and the traditional multiple evaporation crystallization process is not adopted, but the lithium hydroxide is crystallized through the insolubility of the lithium hydroxide in the organic solvent, so that the crystallization process is greatly simplified, and the production cost of the battery grade lithium hydroxide monohydrate is further reduced. In addition, lithium carbonate impurities from different sources are different, and lithium carbonate from different sources is adopted to prepare the battery grade lithium hydroxide monohydrate with high yield through a multi-step impurity removal process, so that the universality of the process method is provided. Therefore, the invention solves the problems of complicated production process and high production cost of the battery grade lithium hydroxide monohydrate prepared by lithium carbonate in the prior art.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (10)
1. A method for preparing battery grade lithium hydroxide monohydrate from low-grade lithium carbonate, the method comprising the steps of:
preparing low-quality lithium carbonate, quicklime and water into slurry according to a certain proportion, putting the slurry into a reaction kettle for reaction, and filtering the lithium hydroxide slurry obtained by the reaction after the reaction is finished to obtain causticized liquid and calcium slag;
step two, preparing lithium hydroxide solution, namely adding a preset amount of metal precipitant into the causticizing solution obtained in the step one, and filtering by a filtering device to obtain lithium hydroxide solution;
step three, preparing lithium hydroxide solid, namely pumping the lithium hydroxide solution obtained by filtering in the step two into a crystallizer filled with an organic solvent, stirring and crystallizing, and performing solid-liquid separation on the precipitate to obtain lithium hydroxide solid and filtrate;
and fourthly, treating lithium hydroxide solids, leaching the lithium hydroxide solids obtained by separation in the third step, and drying the leached lithium hydroxide solids through drying equipment to obtain battery-grade lithium hydroxide monohydrate.
2. The method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate according to claim 1, wherein the low grade lithium carbonate is Li 2 CO 3 The content is 70% -98.5%, and the slurry comprises the following components: li (Li) 2 CO 3 CaO=1:1.05-1.5, and the solid-liquid ratio is 1:8-12, wherein the causticizing temperature is 80-95 ℃, and the causticizing time is 1-10 h.
3. The method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate according to claim 1, wherein the metal precipitant is one or more of oxalic acid or oxalate, phosphoric acid or phosphate, sodium sulfite and potassium sulfite, and the filtering device adopts a precision filter.
4. The method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate according to claim 1, wherein the organic solvent is one or more of methanol, ethanol, and acetone.
5. The method for preparing battery grade lithium hydroxide monohydrate by low grade lithium carbonate according to claim 1, wherein the lithium hydroxide solution is pumped into a crystallizer containing an organic solvent while stirring at a rate of 400rpm to 700rpm for a period of 0.5h to 3h.
6. The method for preparing battery grade lithium hydroxide monohydrate from low grade lithium carbonate according to claim 5, wherein the ratio of lithium hydroxide solution pumping to organic solvent is between 1:3 and 6.
7. The method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate according to claim 1, wherein the lithium hydroxide solid obtained by the separation in the step three is leached by the organic solvent, and the leached lithium hydroxide solid is dried by one of a drying cylinder type drying device, a hot air type drying device or a far infrared type drying device, so that the water content of the dried lithium hydroxide solid is reduced to below 1%.
8. The method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate according to any of claims 1-7, wherein the causticizing reaction, preparing low-grade lithium carbonate, quicklime and water into slurry according to a certain proportion, putting the slurry into a reaction kettle for reaction, and filtering the lithium hydroxide slurry obtained by the reaction after the reaction is finished to obtain causticizing solution and calcium slag, wherein the method comprises the steps of: and filtering the lithium hydroxide slurry through plate-and-frame filter pressing equipment to obtain causticizing liquid and calcium slag, and calcining the calcium slag at high temperature to obtain quicklime to be recycled as a causticizing reaction raw material.
9. The method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate according to claim 8, wherein the step of preparing lithium hydroxide solid, pumping the lithium hydroxide solution obtained by filtering in the step two into a crystallizer containing an organic solvent, stirring and crystallizing, and performing solid-liquid separation on the precipitate to obtain lithium hydroxide solid and filtrate comprises the following steps: and (3) carrying out low-temperature distillation or vacuum distillation on the filtrate to recover the organic solvent in the filtrate into the crystallizer, wherein the low-temperature distillation temperature is 40-80 ℃, and the vacuum distillation pressure is-5 Pa-10 Pa.
10. The method for preparing battery grade lithium hydroxide monohydrate by using low-grade lithium carbonate according to claim 8, wherein the step of leaching the lithium hydroxide solid obtained by the separation in the step three, and then drying the leached lithium hydroxide solid by a drying device to obtain the battery grade lithium hydroxide monohydrate comprises the following steps: and (3) carrying out low-temperature distillation or vacuum distillation on the wastewater generated by leaching, so that the organic solvent in the filtrate is recycled to the crystallizer.
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