Anhydrous lithium hydroxide moisture determination system

Abstract

The utility model discloses an anhydrous lithium hydroxide moisture determination system, which comprises a gas source module, a heating module, a reaction measurement module and a Cartesian solution supply module, the heating module is respectively connected to the gas source module and the reaction measurement module, the gas source module is connected to the heating module through a first communication piece so as to introduce inert gas into the heating module, and the Cartesian solution supply module is connected to the reaction measurement module through a second communication piece. The heating module is connected to the reaction measurement module through a second communication piece, inert gas brings moisture escaped from the heating module into the reaction measurement module through the second communication piece, and the Karsi solution supply module provides quantitative Karsi solution for the reaction measurement module through a third communication piece so as to react with the moisture and measure release voltage; and measuring the water content of the sample. In the anhydrous lithium hydroxide moisture measuring process, the anhydrous lithium hydroxide moisture measuring device is easy to operate, residues are avoided, cross contamination can be avoided, the sample bottle can be repeatedly used after being cleaned, and cost consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the field of moisture measurement, in particular to an anhydrous lithium hydroxide moisture measurement system. Background Art

[0002] The conventional production process of high-capacity lithium-ion battery NCM materials or cathode active materials is to prepare the precursor by co-precipitation method. The precursor is mixed with lithium carbonate or lithium hydroxide and calcined in an oxygen-rich environment. During the cooling process, the components such as CO2 and H2O generated during the calcination of the material need to be discharged to prevent the formation of impurities on the surface of the material. During the calcination process, lithium carbonate releases carbon dioxide, resulting in gas in the battery and a loss of about 60% by weight of the lithium source. During the calcination process, lithium hydroxide releases water and loses about 38% by weight of the lithium source. The lithium salt plant directly supplies anhydrous lithium hydroxide to the positive electrode plant, which can avoid the process of removing crystal water during the sintering process. However, lithium hydroxide usually exists in the form of hydrate LiOH·H2O, and due to the aging of the lithium hydroxide hydrate and its hygroscopicity, the water content of lithium hydroxide may change.

[0003] At present, the Karl Fischer method is generally used to measure the water content of inorganic and organic compounds. The Karl Fischer method belongs to the iodine titration method. Its basic principle is that when iodine is used to oxidize sulfur dioxide, a certain amount of water is required to participate in the reaction: I2 +SO2+2H2O→2HI+H2SO4, can be applied to the determination of water content in most inorganic and organic compounds. However, since lithium hydroxide can react with HI (Karl Fischer reaction product) to generate water, and the existing device for Karl Fischer determination does not add corresponding equipment to treat the generated water, the generated water will affect the determination of water content in lithium hydroxide, resulting in the inability to accurately measure the water content in lithium hydroxide. Utility Model Content

[0004] Based on this, the purpose of the utility model is to provide a water content determination system for anhydrous lithium hydroxide, aiming to solve the problem that HI in the reaction product of the Karl Fischer method reacts with lithium hydroxide to generate water, resulting in the inability to accurately measure the water content in the lithium hydroxide.

[0005] To achieve the above object, the utility model is implemented through the following technical solutions: a water content determination system for anhydrous lithium hydroxide, comprising: a gas source module, a heating module, a reaction measurement module and a Karl Fischer solution supply module connected in sequence;

[0006] The two ends of the heating module are respectively connected to the gas source module and the reaction measurement module. The gas source module is connected to the heating module through a first connecting piece to pass an inert gas into the heating module. The heating module is connected to the reaction measurement module through a second connecting piece. The inert gas brings the moisture escaping from the heating module into the reaction measurement module through the second connecting piece. The Karl Fischer solution supply module provides a quantitative Karl Fischer solution to the reaction measurement module through a third connecting piece to react with the moisture, measure the release voltage, and then reflect the water content of the sample.

[0007] In summary, according to the anhydrous lithium hydroxide moisture determination system proposed by the utility model, the inert gas produced by the gas source module is transported to the heating module. The heating module heats the sample to separate the moisture in the sample and mix it with the inert gas. As the gas expands due to heat, it enters the reaction measurement module from the second connecting piece. At the same time, the Karl Fischer solution supply module provides a quantitative Karl Fischer solution to the reaction measurement module. I2 in the Karl Fischer solution reacts with water, and I2 reacts with water to release voltage. By measuring the voltage, the water content reacting with I2 is measured, and finally the water content in the sample is obtained. In the process of measuring the moisture content of anhydrous lithium hydroxide, the measurement system is not only simple to operate, but also has no residue, which can avoid cross contamination. The sample bottle can be washed and reused, which reduces cost consumption.

[0008] Furthermore, the reaction measurement module includes a measuring bottle, a stirring member disposed in the measuring bottle and used to stir the mixed solution, and a conductive member used to measure the moisture content, wherein the stirring member is used to mix the reaction solution so that the conductive member displays the voltage of the current solution.

[0009] Furthermore, the Carfello solution supply module includes a second volumetric flask and a quantitative flask, the mouth of the quantitative flask is provided with a quantitative valve, and the quantitative flask is connected to the measuring flask via a third connecting piece to provide the Carfello solution into the measuring flask.

[0010] Furthermore, the second volumetric flask and the quantitative flask are connected via a fourth connecting piece, and the second volumetric flask provides the quantitative Karlsruhe solution to the quantitative flask via the fourth connecting piece.

[0011] Furthermore, the gas source module includes a generator bottle and a sealing member arranged at the mouth of the generator bottle, one end of the first connecting member passes through the sealing member and enters the generator bottle, and the other end is connected to the heating module.

[0012] Furthermore, the heating module includes a heating element, a fixing element arranged on the heating element, and a plurality of first volumetric flasks arranged on the fixing element, the sample is arranged in the first volumetric flask, the end of the first connecting element away from the generating bottle is arranged in the first volumetric flask, and the heating element heats the first volumetric flask to mix the moisture and the inert gas.

[0013] Furthermore, one end of the second connecting piece away from the reaction measurement module is arranged in the first volumetric flask, and is arranged in the first volumetric flask through a heating tube with one end of the first connecting piece away from the generating bottle to maintain a mixed state of gas and water.

[0014] Furthermore, one end of the second connecting member away from the first volumetric flask is arranged in the reaction measurement module.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 This is a structural block diagram of an anhydrous lithium hydroxide moisture measurement system in one embodiment of the utility model;

[0018] Figure 2 It is a structural schematic diagram of an anhydrous lithium hydroxide moisture determination system in one embodiment of the utility model.

[0019] Component symbol description:

[0020] Gas source module 10, generating bottle 11, sealing part 12, heating module 20, heating part 21, fixing part 22, first volumetric flask 23, reaction measurement module 30, measuring bottle 31, stirring part 32, conductive part 33, Karlsruhe solution supply module 40, second volumetric flask 41, quantitative bottle 42, first connecting part 50, second connecting part 60, third connecting part 70, fourth connecting part 80. DETAILED DESCRIPTION

[0021] In order to make the purpose, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. Several embodiments of the utility model are given in the accompanying drawings. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the utility model more thorough and comprehensive.

[0022] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may also be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are for illustrative purposes only and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] Please combine Figure 1-Figure 2 , which is a schematic diagram of the structure of a water content determination system of anhydrous lithium hydroxide provided in one embodiment of the utility model, comprises a gas source module 10, a heating module 20, a reaction measurement module 30 and a Karl Fischer solution supply module 40, wherein:

[0025] The gas source module 10 provides a carrier gas for the anhydrous lithium hydroxide moisture determination system, so as to bring the moisture in the heating module 20 into the reaction measurement module 30. At the same time, in order to prevent the carrier gas from affecting the moisture content determination of the system, the carrier gas in this embodiment can be dry air provided by a compressor, or nitrogen or an inert gas provided by an inert gas cylinder as a carrier gas. The gas source module 10 includes a generator bottle 11 and a sealing member 12 provided at the mouth of the generator bottle 11. The generator bottle 11 is used to provide a carrier gas. One end of the first connecting member 50 passes through the sealing member 12 and enters the generator bottle 11. The carrier gas enters the heating component through the first connecting member 50. The sealing member 12 and the mouth of the generator bottle 11 adopt a spiral interface design, which can be easily opened, and the internal polytetrafluoroethylene gasket can be replaced after cleaning for reuse. The bottle stopper is a polytetrafluoroethylene coating, which can effectively prevent the interference of moisture in the atmosphere.

[0026] After receiving the carrier gas provided by the gas source module 10, the heating module 20 heats the sample therein. The heating module 20 includes a heating element 21, a fixing element 22 arranged on the heating element 21, and a plurality of first volumetric flasks 23 arranged on the fixing element 22. The sample is arranged in the first volumetric flask 23. The fixing element 22 is provided with a plurality of fixing holes for placing a plurality of first volumetric flasks 23 for multiple analog measurements. The heating element 21 can also be connected to a balance to automatically read the sample weight. The first connecting element 50 is arranged in the first volumetric flask 23 at one end away from the generating bottle 11, so that the carrier gas passes through the first volumetric flask 23 and the overflowed water is mixed with the carrier gas. The second connecting element 60 is arranged in the first volumetric flask 23 at one end away from the reaction measurement module 30, and is fixedly arranged in the first volumetric flask 23 through a heating tube and the first connecting element 50. While being used to maintain the mixed state of the carrier gas and the water, it also effectively prevents the water from condensing in the process of being introduced from the first volumetric flask 23 into the reaction measurement module 30, and avoids cross contamination between samples.

[0027] Furthermore, the Carfign solution supply module 40 includes a second volumetric flask 41 and a quantitative bottle 42, the mouth of the quantitative bottle 42 is provided with a quantitative valve, the second volumetric flask 41 and the quantitative bottle 42 are connected by a fourth connecting piece 80, and the two ends of the fourth connecting piece 80 extend into the second volumetric flask 41 and the quantitative bottle 42 respectively. The second volumetric flask 41 is filled with Carfign solution, and the quantitative bottle 42 controls the dosage of the Carfign solution entering the quantitative bottle 42 through the quantitative valve, and also controls the dosage of the Carfign solution provided by the quantitative bottle 42 to the reaction measurement module 30.

[0028] Furthermore, the reaction measurement module 30 includes a measuring bottle 31, a stirring member 32 disposed in the measuring bottle 31 and used to stir the mixed solution, and a conductive member 33 for measuring the water content. The end of the second connecting member 60 away from the first volumetric bottle 23 is disposed in the measuring bottle 31, and the end of the third connecting member 70 away from the quantitative bottle 42 is disposed in the measuring bottle 31, and the stirring member 32 and the conductive member 33 are both disposed in the measuring bottle 31. Since the Karl Fischer solution contains water, it is difficult to measure the water content in the sample by direct measurement. Therefore, the system reacts I2 in the Karl Fischer solution with the water in the sample brought into the measuring bottle 31 by the carrier gas to obtain I2=2I - -2e, the water is stirred evenly by the stirring element 32, reacting with I2 in the Karl Fischer solution to discharge, and then the discharge amount is displayed by the conductive element 33 to calculate the water content accordingly, and then the water content in the sample is measured.

[0029] Accordingly, the specific steps of the method for using the anhydrous lithium hydroxide moisture determination system include:

[0030] (1) Instrument preparation

[0031] Fix the first volumetric flask on the fixing piece, use the first connecting piece to connect the generating bottle and the first volumetric flask, and fix the heating tube to the first connecting piece and the second connecting piece, and use the second connecting piece, the third connecting piece and the fourth connecting piece in sequence to connect the heating module, the reaction measurement module and the Karl Fischer solution supply module in series.

[0032] (2) Sample preparation

[0033] Weigh an appropriate amount of anhydrous lithium hydroxide sample, place it in the first volumetric flask and seal it.

[0034] Take an anhydrous lithium hydroxide sample with a water content of <0.1% and number it as sample 1-1. Weigh a certain mass of sample 1-1 in a sample bottle, accurately to 0.0001g, add different masses of water, the spiked amounts are 0.02%, 0.04%, 0.06%, respectively, and number the spiked samples as: sample 1-2, sample 1-3, sample 1-4; take an anhydrous lithium hydroxide sample with a water content of >0.1%, number it as sample 2-1. Weigh a certain mass of sample 2-1 in a sample bottle, accurately to 0.0001g, add different masses of water, the spiked amounts are 0.5%, 1%, 2%, respectively, and number the spiked samples as: sample 2-2, sample 2-3, sample 2-4.

[0035] (3) Heat treatment

[0036] The temperature range is 50-250°C, the gas flow rate is 10-150mL / min, and the moisture content of multiple samples can be measured continuously. In this embodiment, the heating element temperature is set to 120°C, and the nitrogen (carrier gas) flow rate is set to 100mL / min.

[0037] (4) Water titration

[0038] Add Karl Fischer solution into the measuring bottle for testing. When the potential of the conductive piece reaches the end point, the water content in the sample is measured.

[0039] In summary, according to the anhydrous lithium hydroxide moisture determination system proposed by the utility model, the inert gas produced by the gas source module is transported to the heating module. The heating module heats the sample to separate the moisture in the sample and mix it with the inert gas. As the gas expands due to heat, it enters the reaction measurement module from the second connecting piece. At the same time, the Karl Fischer solution supply module provides a quantitative Karl Fischer solution to the reaction measurement module. I2 in the Karl Fischer solution reacts with water, and I2 reacts with water to release voltage. By measuring the voltage, the water content reacting with I2 is measured, and finally the water content in the sample is obtained. In the process of measuring the moisture content of anhydrous lithium hydroxide, the measurement system is not only simple to operate, but also has no residue, which can avoid cross contamination. The sample bottle can be washed and reused, which reduces cost consumption.

[0040] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0041] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A water content determination system for anhydrous lithium hydroxide, characterized in that: The anhydrous lithium hydroxide moisture determination system comprises: A gas source module, a heating module, a reaction measurement module and a Karl Fischer solution supply module are connected in sequence; The two ends of the heating module are respectively connected to the gas source module and the reaction measurement module. The gas source module is connected to the heating module through a first connecting piece to pass an inert gas into the heating module. The heating module is connected to the reaction measurement module through a second connecting piece. The inert gas brings the moisture escaping from the heating module into the reaction measurement module through the second connecting piece. The Karl Fischer solution supply module provides a quantitative Karl Fischer solution to the reaction measurement module through a third connecting piece to react with the moisture, measure the release voltage, and then reflect the water content of the sample.

2. The anhydrous lithium hydroxide moisture measurement system according to claim 1, characterized in that: The reaction measurement module comprises a measuring bottle, a stirring member arranged in the measuring bottle and used for stirring the mixed solution, and a conductive member for measuring the moisture content. The stirring member is used for mixing the reaction solution so that the conductive member displays the voltage of the current solution.

3. The anhydrous lithium hydroxide moisture measurement system according to claim 1, characterized in that: The Carfello solution supply module comprises a second volumetric flask and a quantitative flask. The mouth of the quantitative flask is provided with a quantitative valve. The quantitative flask is connected with the measuring flask via a third connecting piece to provide the Carfello solution into the measuring flask.

4. The anhydrous lithium hydroxide moisture measurement system according to claim 3, characterized in that: The second volumetric flask and the quantitative flask are connected via a fourth connecting piece, and the second volumetric flask provides the quantitative Karlsruhe solution to the quantitative flask via the fourth connecting piece.

5. The anhydrous lithium hydroxide moisture measurement system according to claim 1, characterized in that: The gas source module includes a generator bottle and a sealing member arranged at the mouth of the generator bottle. One end of the first connecting member passes through the sealing member and enters the generator bottle, and the other end is connected to the heating module.

6. The anhydrous lithium hydroxide moisture measurement system according to claim 1, characterized in that: The heating module includes a heating element, a fixing element arranged on the heating element, and a plurality of first volumetric flasks arranged on the fixing element. The sample is arranged in the first volumetric flask, and the end of the first connecting element away from the generating bottle is arranged in the first volumetric flask. The heating element heats the first volumetric flask to mix the moisture and the inert gas.

7. The anhydrous lithium hydroxide moisture measurement system according to claim 6, characterized in that: The end of the second connecting piece away from the reaction measurement module is arranged in the first volumetric flask, and is arranged in the first volumetric flask through a heating tube with the end of the first connecting piece away from the generating bottle to maintain a mixed state of gas and water.

8. The anhydrous lithium hydroxide moisture measurement system according to claim 7, characterized in that: One end of the second connecting member away from the first volumetric flask is arranged in the reaction measurement module.

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