Method and device for quickly judging proportion of rare earth molten salt component

Abstract

This invention discloses a method and apparatus for rapidly determining the component ratio of rare earth molten salts. First, a database of temperature drop curves containing various molten salt components is established. Then, a temperature acquisition device is used to collect the temperature of the molten salt sample under test during its cooling process at room temperature, and the temperature drop curve data of the sample is saved. The temperature drop curve of the sample is compared with the data in the established database to identify the molten salt component with the highest similarity in temperature drop curves. This component is then used as the component ratio of the molten salt sample under test. This method and apparatus can provide reliable and convenient data support for the rapid detection of praseodymium-neodymium fluoride and lithium fluoride in molten salts in actual production environments, achieving the goal of stabilizing the electrolyte molten salt system and improving the quality of rare earth metals.

Description

Technical Field

[0001] This invention relates to the field of rare earth molten salt technology, and in particular to a method and apparatus for rapidly determining the component ratio of rare earth molten salt. Background Technology

[0002] Rare earth elements are widely used in agriculture, national defense, industry, and environmental protection, and are one of my country's most important "strategic resources." Currently, molten salt electrolysis is commonly used in industry to prepare and produce rare earth metals and their alloys, such as praseodymium, neodymium, praseodymium-neodymium, dysprosium-iron, lanthanum-cerium, gadolinium-iron, scandium aluminum, and yttrium aluminum. Rare earth electrolysis requires a molten salt environment, which contains three components: rare earth fluoride (ReF3), lithium fluoride (LiF), and rare earth oxide (Re2O3). The content of rare earth oxide is relatively constant, while the stable ratio of rare earth fluoride and lithium fluoride plays a crucial role in the stable and efficient electrolysis process. Factors such as molten salt volatilization, leakage, and the participation of rare earth fluoride in the electrolysis reaction can alter the molten salt component ratio, thus affecting the normal operation of the rare earth electrolysis process. Specifically, if the proportion of rare earth fluoride decreases, the amount of raw materials dissolved in the molten salt will decrease, the molten salt resistance will drop, and a series of adverse consequences will arise. When the ratio of rare earth fluorides to lithium fluorides in molten salt becomes unbalanced, it is necessary to promptly replenish rare earth fluorides or lithium fluorides to readjust the composition of the molten salt. Therefore, rapid determination of the rare earth molten salt composition ratio is of guiding significance for which component to replenish and the amount to replenish.

[0003] Because the rare earth electrolysis process requires a temperature of around 1100℃, the molten salt is in a molten state and is corrosive. Therefore, online detection of the molten salt composition at high temperatures is not yet possible. After cooling and solidification, the proportion of molten salt components can be detected by chemical analysis. This method requires sampling and sample preparation before laboratory analysis, and it cannot detect the component proportion in real time or online. As a result, rare earth fluorides or lithium fluorides cannot be replenished in time during the actual electrolysis process, leading to an imbalance in the proportion of molten salt components and ultimately affecting the quality of rare earth metals. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for rapid determination of the component ratio of rare earth molten salt. This method and apparatus can provide reliable and convenient data support for the rapid detection of praseodymium fluoride and lithium fluoride in molten salt in actual production environments, thereby achieving the goal of stabilizing the electrolyte molten salt system and improving the quality of rare earth metals.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for rapidly determining the component ratio of rare earth molten salt, the method comprising:

[0007] Step 1: Establish a database of temperature drop curves containing various molten salt components;

[0008] Step 2: Use a molten salt cooling process temperature acquisition device to collect the temperature of the molten salt sample to be tested during the cooling process at room temperature, and save the temperature drop curve data of the molten salt sample to be tested.

[0009] Step 3: Compare the temperature drop curve of the molten salt sample to be tested obtained in Step 2 with the data in the temperature drop curve database established in Step 1, find the molten salt component with the highest similarity in temperature drop curve, and take the molten salt component with the highest similarity as the component ratio of the molten salt sample to be tested.

[0010] A device for rapidly determining the component ratio of rare earth molten salt, the device comprising a temperature acquisition device for the molten salt cooling process and a terminal device, wherein:

[0011] The molten salt cooling process temperature acquisition device is used to acquire the temperature of the molten salt sample to be tested during the cooling process at room temperature and save the temperature drop curve data of the molten salt sample to be tested.

[0012] The terminal device is equipped with a temperature drop curve database containing various molten salt components. By matching and analyzing the molten salt temperature data of the molten salt sample to be tested with the data in the temperature drop curve database, the molten salt component with the highest degree of similarity in temperature drop curve is identified, and the molten salt component with the highest degree of similarity is used as the component ratio of the molten salt sample to be tested.

[0013] As can be seen from the technical solutions provided by the present invention, the above-mentioned methods and devices can provide reliable and convenient data support for the rapid detection of praseodymium fluoride and lithium fluoride in molten salt in actual production environments, thereby achieving the goal of stabilizing the electrolyte molten salt system and improving the quality of rare earth metals. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic flowchart of a method for rapidly determining the proportion of rare earth molten salt components provided in an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the resampling strategy at different stages in the temperature drop curve described in the embodiments of the present invention;

[0017] Figure 3 This is a schematic diagram of the device described in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, and do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] The molten salt used in the molten salt electrolysis process for producing rare earth metals contains three substances: rare earth fluorides, lithium fluorides, and rare earth oxides. When the proportion of any one of these substances changes, the physicochemical properties of the molten salt alter, thus changing the temperature-time relationship during cooling. Specifically, when a molten salt composed of rare earth fluorides, lithium fluorides, and rare earth oxides is cooled uniformly, a phase transition reaction occurs within the system, generating heat flow. During cooling, the initially linear temperature drop curve changes its slope at the phase transition temperature, forming a complex temperature drop curve trajectory. The temperature drop curve trajectories differ depending on the component ratios of the molten salt. Based on the temperature drop curve trajectory, the component ratios of the molten salt can be analyzed in reverse. Based on the above principle, such as... Figure 1 The diagram shows a flowchart of a method for rapidly determining the proportion of rare earth molten salt components according to an embodiment of the present invention. The method includes:

[0020] Step 1: Establish a database of temperature drop curves containing various molten salt components;

[0021] In this step, a molten salt sample with a known composition ratio above 1000-1200℃ is first placed in a pouring cup, and the temperature drop curve data of the molten salt sample is detected and recorded using a device for detecting the molten salt composition in the rare earth electrolysis process.

[0022] Once the temperature of the molten salt sample has cooled to 400-600℃, data acquisition is stopped, and the collected temperature drop data is plotted as a temperature drop curve.

[0023] Repeat the above steps to establish a mapping relationship between molten salt samples with different component ratios and their corresponding temperature drop curves, and construct a temperature drop curve database containing various molten salt components.

[0024] Step 2: Use a molten salt cooling process temperature acquisition device to collect the temperature of the molten salt sample to be tested during the cooling process at room temperature, and save the temperature drop curve of the molten salt sample to be tested.

[0025] Step 3: Compare the temperature drop curve of the molten salt sample to be tested obtained in Step 2 with the data in the temperature drop curve database established in Step 1, find the molten salt component with the highest similarity in temperature drop curve, and take the molten salt component with the highest similarity as the component ratio of the molten salt sample to be tested.

[0026] In this step, the temperature drop curve of the molten salt sample to be tested is divided into a phase change stage and a phase change-free stage. The dividing criterion is that the temperature drop curve in the phase change-free stage is linear, while the temperature drop curve in the phase change stage is non-linear, and the slope of the temperature drop curve changes.

[0027] The temperature drop curve of the molten salt sample to be tested is resampled; specifically, such as... Figure 2 The diagram illustrates the resampling strategy for different stages of the temperature drop curve in this embodiment of the invention. During the cooling process, resampling is performed at 10 times / second in the non-phase-change stage and at 100 times / second in the phase-change stage. Then, the resampled temperature and corresponding time points are used to form the temperature drop curve time series T of the molten salt sample to be tested, expressed as follows:

[0028] T=[T(s0, f0), T(s1, f1), T(s0, f0). . . ]

[0029] Where T represents the time series of the temperature drop curve, including the alternating stages of no phase change and phase change during molten salt cooling, such as no phase change stage - phase change stage - no phase change stage, etc.; T(s0, f0) represents the molten salt cooling temperature in the no phase change stage, where s0 represents no phase change and f0 represents the sampling rate in the no phase change stage; T(s1, f1) represents the molten salt cooling temperature in the phase change stage, where s1 represents phase change and f1 represents the sampling rate in the phase change stage.

[0030] The correlation coefficient r between the time series T of the temperature drop curve of the molten salt sample to be tested and the data T' in the temperature drop curve database established in step 1 is calculated, and the expression is as follows:

[0031] r(T,T')=Cov(T,T') / (Var(T)*Var(T')) 1 / 2

[0032] Where r(T,T') represents the correlation coefficient between the molten salt sample temperature drop curve sequence T and the standard sequence T' in the database; Cov(T,T') represents the covariance between the two; and Var represents the sequence variance.

[0033] Repeat the above steps to iterate through the entire temperature drop curve database, obtaining the component data from the database with the highest correlation coefficient, and using the proportion of this component data as the component proportion of the molten salt sample to be tested; where the expression for the maximum correlation coefficient r_max is:

[0034] r_max=max(r1,r2,r3...).

[0035] Based on the above method, embodiments of the present invention also provide a device for rapidly determining the proportion of rare earth molten salt components, such as... Figure 3The diagram shown is a structural schematic of the device according to an embodiment of the present invention. The device includes a temperature acquisition device for the molten salt cooling process and a terminal device 7, wherein:

[0036] The molten salt cooling process temperature acquisition device is used to acquire the temperature of the molten salt sample to be tested during the cooling process at room temperature and save the temperature drop curve data of the molten salt sample to be tested.

[0037] The terminal device 7 is equipped with a temperature drop curve database containing various molten salt components. By matching and analyzing the molten salt temperature data of the molten salt sample to be tested with the data in the temperature drop curve database, the molten salt component with the highest similarity in temperature drop curves is identified, and this molten salt component with the highest similarity is used as the component proportion of the molten salt sample to be tested. The specific implementation process of the terminal device 7 is described in the above method embodiment.

[0038] In specific implementation, such as Figure 3 As shown, the temperature acquisition device for the molten salt cooling process specifically includes a pouring cup 1, a thermocouple 2, a metal protrusion 3, a bracket 4, a cable 5, and a temperature acquisition device 6, wherein:

[0039] The pouring cup 1 is used to hold the molten salt sample to be tested;

[0040] The bracket 4 is used to fix the pouring cup 1, and the bracket is provided with two metal protrusions 3 for supporting the pouring cup 1;

[0041] The thermocouple 2 is embedded in the pouring cup 1 from the bottom and is used to measure the temperature of the molten salt in the pouring cup 1. The two leads of the thermocouple 2 are pressed into contact with the two metal protrusions 3 respectively.

[0042] The two metal protrusions 3 on the bracket 4 are respectively connected to the cable 5, and the potential difference signal of the thermocouple 2 is transmitted to the temperature acquisition device 6 through the cable 5.

[0043] The temperature acquisition device 6 is connected to the thermocouple 2. The temperature acquisition device 6 communicates with the terminal device 7 via its own cable 8 or wireless Bluetooth, and is used to transmit the molten salt temperature data of the molten salt sample to be tested collected by the thermocouple 2 to the terminal device 7.

[0044] It is worth noting that the contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0045] In summary, the method and apparatus described in this invention, taking into account the different temperature drop curves of molten salts with different component ratios of rare earth fluoride-lithium fluoride-rare earth oxide, collected a large amount of data on the temperature drop of molten salts with different component ratios. By measuring the temperature drop curves of the molten salts, a temperature drop curve database was established, providing reliable and convenient data support for the rapid detection of molten salt components in actual production environments. Furthermore, based on the temperature drop curve of the molten salt to be tested, the ratio of rare earth fluoride and lithium fluoride was detected online, achieving real-time online detection of component ratios and determining whether rare earth fluoride or lithium fluoride needs to be added to the electrolytic cell to maintain the stability of the electrolyte molten salt system, improve current efficiency, and enhance product quality.

[0046] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for quickly judging the proportion of rare earth molten salt components, characterized in that, The method includes: Step 1: Establish a database of temperature drop curves containing various molten salt components; Step 2: Use a molten salt cooling process temperature acquisition device to collect the temperature of the molten salt sample to be tested during the cooling process at room temperature, and save the temperature drop curve data of the molten salt sample to be tested. Step 3: Compare the temperature drop curve of the molten salt sample to be tested obtained in Step 2 with the data in the temperature drop curve database established in Step 1, find the molten salt component with the highest similarity in temperature drop curve, and take the molten salt component with the highest similarity as the component ratio of the molten salt sample to be tested. The process of step 3 is as follows: The temperature drop curve of the molten salt sample to be tested is divided into a phase change stage and a phase changeless stage. The dividing criteria are that the temperature drop curve in the phase changeless stage is linear, while the temperature drop curve in the phase change stage is non-linear and the slope of the temperature drop curve changes. The temperature drop curve of the molten salt sample to be tested is resampled; specifically, resampling is performed at 10 times / second during the phase-change-free stage of cooling, and at 100 times / second during the phase-change-free stage; then, the time series T of the temperature drop curve of the molten salt sample to be tested is formed using the resampled temperature and the corresponding time point, as expressed below: T=[T(s0,f0),T(s1,f1),T(s0,f0)...] Where T represents the time series of the temperature drop curve, including the alternating stages of no phase change and phase change during molten salt cooling; T(s0, f0) represents the molten salt cooling temperature in the no-phase-change stage, where s0 represents no phase change and f0 represents the sampling rate in the no-phase-change stage; T(s1, f1) represents the molten salt cooling temperature in the phase-change stage, where s1 represents phase change and f1 represents the sampling rate in the phase-change stage. The correlation coefficient r between the time series T of the temperature drop curve of the molten salt sample to be tested and the data T' in the temperature drop curve database established in step 1 is calculated, and the expression is as follows: r(T,T’)=Cov(T,T’) / (Var(T)* Var(T’)) 1 / 2 Where r(T,T') represents the correlation coefficient between the molten salt sample temperature drop curve sequence T and the standard sequence T' in the database; Cov(T,T') represents the covariance between the two; and Var represents the sequence variance. Repeat the above operation to traverse the entire temperature drop curve database, obtain the component data in the temperature drop curve database with the highest correlation coefficient, and use the proportion of this component data as the component proportion of the molten salt sample to be tested. The expression for the maximum correlation coefficient r_max is: r_max=max(r1,r2,r3......).

2. The method for rapid determination of the proportion of rare earth molten salt components according to claim 1, characterized in that, The process of step 1 is as follows: First, a molten salt sample with a known composition ratio above 1000-1200℃ is placed in a pouring cup. The temperature drop curve data of the molten salt sample is detected and recorded using a device for detecting the molten salt composition during rare earth electrolysis. Once the temperature of the molten salt sample has cooled to 400-600℃, data acquisition is stopped, and the collected temperature drop data is plotted as a temperature drop curve. Repeat the above steps to establish a mapping relationship between molten salt samples with different component ratios and their corresponding temperature drop curves, and construct a temperature drop curve database containing various molten salt components.

3. A device for quickly judging the proportion of rare earth molten salt components, characterized in that, The device includes a temperature acquisition device for the molten salt cooling process and terminal equipment, wherein: The molten salt cooling process temperature acquisition device is used to acquire the temperature of the molten salt sample to be tested during the cooling process at room temperature and save the temperature drop curve data of the molten salt sample to be tested. The terminal device contains a database of temperature drop curves for various molten salt components. By matching and analyzing the molten salt temperature data of the molten salt sample to be tested with the data in the database, the molten salt component with the highest degree of similarity in temperature drop curves is identified, and this component with the highest degree of similarity is used as the component proportion of the molten salt sample to be tested. Specifically, this includes: The temperature drop curve of the molten salt sample to be tested is divided into a phase change stage and a phase changeless stage. The dividing criteria are that the temperature drop curve in the phase changeless stage is linear, while the temperature drop curve in the phase change stage is non-linear and the slope of the temperature drop curve changes. The temperature drop curve of the molten salt sample to be tested is resampled; specifically, resampling is performed at 10 times / second during the phase-change-free stage of cooling, and at 100 times / second during the phase-change-free stage; then, the time series T of the temperature drop curve of the molten salt sample to be tested is formed using the resampled temperature and the corresponding time point, as expressed below: T=[T(s0,f0),T(s1,f1),T(s0,f0)...] Where T represents the time series of the temperature drop curve, including the alternating stages of no phase change and phase change during molten salt cooling; T(s0, f0) represents the molten salt cooling temperature in the no-phase-change stage, where s0 represents no phase change and f0 represents the sampling rate in the no-phase-change stage; T(s1, f1) represents the molten salt cooling temperature in the phase-change stage, where s1 represents phase change and f1 represents the sampling rate in the phase-change stage. The correlation coefficient r between the time series T of the temperature drop curve of the molten salt sample to be tested and the data T' in the temperature drop curve database established in step 1 is calculated, and the expression is as follows: r(T,T’)=Cov(T,T’) / (Var(T)* Var(T’)) 1 / 2 Where r(T,T') represents the correlation coefficient between the molten salt sample temperature drop curve sequence T and the standard sequence T' in the database; Cov(T,T') represents the covariance between the two; and Var represents the sequence variance. Repeat the above operation to traverse the entire temperature drop curve database, obtain the component data in the temperature drop curve database with the highest correlation coefficient, and use the proportion of this component data as the component proportion of the molten salt sample to be tested. The expression for the maximum correlation coefficient r_max is: r_max=max(r1,r2,r3......).

4. The device for rapidly judging the proportion of rare earth molten salt components according to claim 3, characterized in that, The temperature acquisition device for the molten salt cooling process specifically includes a pouring cup, a thermocouple, a metal protrusion, a bracket, cables, and a temperature acquisition unit, wherein: The pouring cup is used to hold the molten salt sample to be tested; The bracket is used to fix the pouring cup, and the bracket is provided with two metal protrusions for supporting the pouring cup; The thermocouple is embedded in the bottom of the pouring cup to measure the temperature of the molten salt inside the pouring cup. The two leads of the thermocouple are pressed into contact with two metal protrusions respectively. The two metal protrusions on the bracket are respectively connected to the cable, and the potential difference signal of the thermocouple is transmitted to the temperature acquisition device through the cable; The temperature acquisition device is connected to the thermocouple and communicates with the terminal device via its own cable or wireless Bluetooth to transmit the molten salt temperature data of the molten salt sample to be tested collected by the thermocouple to the terminal device.

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