CN-121978084-A - Method and equipment for measuring content of trace metal in micro-powder lithium carbonate

CN121978084ACN 121978084 ACN121978084 ACN 121978084ACN-121978084-A

Abstract

The application relates to the technical field of metal content measurement, in particular to a method and equipment for measuring trace metal content in micro-powder lithium carbonate, wherein the method comprises the steps of screening characteristic wavelengths from all specific wavelengths of each trace metal element to be measured based on wavelength differences and spectrum intensity differences among different specific wavelengths; analyzing the wavelength difference and the spectrum intensity difference between each nonspecific wavelength and all other nonspecific wavelengths, counting the frequency of the spectrum intensities corresponding to each nonspecific wavelength in the spectrum, determining the baseline interference degree to screen baseline interference wavelengths, and correcting the spectrum intensity based on the spectrum intensities and the baseline interference degree of all the baseline interference wavelengths to determine the content of each trace metal element to be detected in the micro-powder lithium carbonate. According to the application, the accuracy and the reliability of the determination of the trace metal content in the micro-powder lithium carbonate are improved by screening the characteristic wavelength and adaptively subtracting the background noise.

Inventors

LIANG XIAOYU
WEI SHUBIN

Assignees

上海中锂实业有限公司

Dates

Publication Date: 20260505
Application Date: 20260325

Claims (10)

1. The method for measuring the content of trace metals in the micro-powder lithium carbonate is characterized by comprising the following steps of: Acquiring the spectrum of the micro-powder lithium carbonate and the spectrum intensity of each trace metal element to be detected under all specific wavelengths, wherein the specific wavelengths comprise a main wavelength and a secondary wavelength; determining the characteristic degree of each trace metal element to be detected under any auxiliary wavelength based on the difference between the spectrum intensity of each trace metal element to be detected under any auxiliary wavelength and the main wavelength, the wavelength difference between the spectrum intensity of each trace metal element to be detected and all other auxiliary wavelengths, and the average distribution of the spectrum intensity of each trace metal element to be detected under all auxiliary wavelengths; Based on the difference between the spectrum intensities of each trace metal element to be detected under any one pair of wavelengths and all other pairs of wavelengths, optimizing the feature degree of each trace metal element to be detected under any one pair of wavelengths, and combining the obtained optimized feature degree of each trace metal element to be detected under the main wavelength to screen out the feature wavelengths from all specific wavelengths of each trace metal element to be detected; The baseline interference degree of each nonspecific wavelength is determined by analyzing the wavelength difference and the spectrum intensity difference between each nonspecific wavelength and all other nonspecific wavelengths and counting the occurrence frequency of the spectrum intensity corresponding to each nonspecific wavelength, so as to screen baseline interference wavelengths from all nonspecific wavelengths; based on the corrected spectrum intensity, the content of each trace metal element to be detected in the micro-powder lithium carbonate is determined.
2. The method for determining the trace metal content in the micro-powder lithium carbonate according to claim 1, wherein the expression of the feature degree of each trace metal element to be detected under any auxiliary wavelength is: In the formula (I), in the formula (II), Representing the characteristic degree of the ith trace metal element to be detected under the secondary wavelength j; Representing a judgment factor obtained based on the difference between the spectrum intensity of the ith trace metal element to be detected under the secondary wavelength j and the spectrum intensity of the main wavelength; a normalized value representing the minimum value in the wavelength difference between the secondary wavelength j of the ith trace metal element and all specific wavelengths of the nth trace metal element in all trace metal elements except the ith trace metal element in the spectrum of the micro-powder lithium carbonate; Representing the result of normalization of the average value of the spectrum intensity of the nth trace metal element in all trace metal elements except the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate at all specific wavelengths; the amounts of all trace metal elements except the ith trace metal element in the spectrum of the micro-powder lithium carbonate are shown.
3. The method for determining trace metal content in micro-powder lithium carbonate according to claim 1, wherein the step of optimizing the feature of each trace metal element to be tested at any one sub-wavelength comprises: Optimized feature degree of ith trace metal element to be detected under secondary wavelength j The expression of (2) is: In the formula (I), in the formula (II), The characteristic degree of the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate under the secondary wavelength j is shown; the result of the spectrum intensity of the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate under the secondary wavelength j is shown as compared with the spectrum intensity under the upper secondary wavelength m; Representing the result of the spectrum intensity ratio of the ith trace metal element to be detected at the auxiliary wavelength j to the spectrum intensity at the upper auxiliary wavelength m, which is obtained in the atomic emission spectrum database; Representing the characteristic degree of the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate under the secondary wavelength m; The number of all the sub-wavelengths of the ith trace metal element to be measured in the spectrum of the micro-powder lithium carbonate is represented, and norm [ ] represents the normalization function.
4. The method for determining the trace metal content in micro-powder lithium carbonate according to claim 1, wherein the characteristic wavelength is a specific wavelength corresponding to the maximum optimized characteristic degree under each trace metal element to be detected.
5. The method for determining the trace metal content in the micro-powder lithium carbonate according to claim 1, wherein the method for determining the baseline interference degree of each non-specific wavelength is as follows: Determining the intensity similarity of each nonspecific wavelength by analyzing the wavelength difference and the spectrum intensity difference between each nonspecific wavelength and all other nonspecific wavelengths; The baseline interference for each non-specific wavelength is the result of the positive fusion of the frequency of occurrence of the spectral intensity corresponding to each non-specific wavelength in the spectrum with the intensity similarity.
6. The method for determining the content of trace metals in micro-powder lithium carbonate according to claim 5, wherein the method for determining the intensity similarity of each nonspecific wavelength is as follows: In the spectrum of the micro-powder lithium carbonate, calculating the difference ratio of the spectrum intensity between each nonspecific wavelength and any other nonspecific wavelength and the wavelength distance between the nonspecific wavelength and any other nonspecific wavelength, and marking the result as the difference characteristic value between each nonspecific wavelength and any other nonspecific wavelength; And calculating the summation of difference characteristic values between each nonspecific wavelength and all other nonspecific wavelengths, wherein the intensity similarity of each nonspecific wavelength and the summation form a negative correlation.
7. The method for determining the trace metal content in the micro-powder lithium carbonate according to claim 1, wherein the step of screening the baseline interference wavelength from all the nonspecific wavelengths comprises the steps of: taking the average value of the baseline interference degree of all nonspecific wavelengths in the spectrum of the micro-powder lithium carbonate as a division threshold value, and taking the nonspecific wavelength with the baseline interference degree larger than the division threshold value as the baseline interference wavelength.
8. The method for determining the trace metal content in the lithium carbonate micropowder according to claim 1, wherein the step of correcting the spectral intensity of each trace metal element to be measured at the characteristic wavelength comprises the steps of: spectral intensity of ith trace metal element to be detected corrected under characteristic wavelength in spectrum of micro-powder lithium carbonate The expression of (2) is: In the formula (I), in the formula (II), The spectrum intensity of the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate under the characteristic wavelength is represented; 、 respectively representing the spectrum intensity and the baseline interference degree of the micro-powder lithium carbonate under the baseline interference wavelength z in the spectrum; spectral intensities representing all baseline interference wavelengths within the spectrum of the micronized lithium carbonate; The optimized characteristic degree of the ith trace metal element to be detected in the spectrum of the micro-powder lithium carbonate under the characteristic wavelength is shown.
9. The method for determining the content of trace metals in micro-powder lithium carbonate according to claim 1, wherein the determining the content of each trace metal element to be detected in the micro-powder lithium carbonate comprises: Acquiring a concentration-spectral intensity curve equation of each trace metal element to be detected; substituting the spectral intensity of each trace metal element to be detected in the spectrum of the micro-powder lithium carbonate into a concentration-spectral intensity curve equation to obtain the concentration of each trace metal element to be detected.
10. A micro metal content measuring device in micro lithium carbonate, comprising a memory, a processor and a computer program stored in the memory and running on the processor, characterized in that the processor, when executing the computer program, realizes the steps of a micro metal content measuring method in micro lithium carbonate according to any one of claims 1-9.

Description

Method and equipment for measuring content of trace metal in micro-powder lithium carbonate Technical Field The application relates to the technical field of metal content measurement, in particular to a method and equipment for measuring the content of trace metal in micro-powder lithium carbonate. Background The purity of the micro-powder lithium carbonate serving as a key precursor of a core positive electrode material of a new energy battery directly determines the energy density, the cycle life and the safety of the battery. In the production process, even if the content of the trace metal impurities such as Fe, cu, zn, ni, cr, co is extremely low, side reactions in the battery can be initiated, so that serious potential safety hazards such as capacity attenuation and thermal runaway are caused. Therefore, quantitative analysis with high precision and high reliability is carried out on the trace metal elements, and the quantitative analysis is a key control link for guaranteeing the quality and the performance of the lithium battery material. In the trace metal content measurement of micro-powder lithium carbonate, the commonly used spectrum technology is inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectrometry (ICP-MS), but the inherent limitations restrict the accuracy of the trace metal content measurement, and are specifically reflected in the two aspects that firstly, the emission lines of different elements can overlap with each other to cause spectrum peak interference, secondly, baseline interference such as banded spectrum, background noise and the like is difficult to effectively correct, the two problems commonly cause deviation on the measurement results of key trace metals such as Fe, cu, zn and the like, the actual concentration of the trace metals cannot be accurately reflected, and additional errors are introduced in imperfect baseline correction, so that the accuracy and reliability of the trace metal content measurement in the micro-powder lithium carbonate are reduced. Disclosure of Invention In order to solve the technical problems, the application aims to provide a method and equipment for measuring the content of trace metals in micro-powder lithium carbonate, and the adopted technical scheme is as follows: In a first aspect, an embodiment of the present application provides a method for determining a content of trace metals in micro-powder lithium carbonate, the method comprising the steps of: Acquiring the spectrum of the micro-powder lithium carbonate and the spectrum intensity of each trace metal element to be detected under all specific wavelengths, wherein the specific wavelengths comprise a main wavelength and a secondary wavelength; determining the characteristic degree of each trace metal element to be detected under any auxiliary wavelength based on the difference between the spectrum intensity of each trace metal element to be detected under any auxiliary wavelength and the main wavelength, the wavelength difference between the spectrum intensity of each trace metal element to be detected and all other auxiliary wavelengths, and the average distribution of the spectrum intensity of each trace metal element to be detected under all auxiliary wavelengths; Based on the difference between the spectrum intensities of each trace metal element to be detected under any one pair of wavelengths and all other pairs of wavelengths, optimizing the feature degree of each trace metal element to be detected under any one pair of wavelengths, and combining the obtained optimized feature degree of each trace metal element to be detected under the main wavelength to screen out the feature wavelengths from all specific wavelengths of each trace metal element to be detected; The baseline interference degree of each nonspecific wavelength is determined by analyzing the wavelength difference and the spectrum intensity difference between each nonspecific wavelength and all other nonspecific wavelengths and counting the occurrence frequency of the spectrum intensity corresponding to each nonspecific wavelength, so as to screen baseline interference wavelengths from all nonspecific wavelengths; based on the corrected spectrum intensity, the content of each trace metal element to be detected in the micro-powder lithium carbonate is determined. Preferably, the expression of the feature degree of each trace metal element to be detected under any auxiliary wavelength is: In the formula (I), in the formula (II), Representing the characteristic degree of the ith trace metal element to be detected under the secondary wavelength j; Representing a judgment factor obtained based on the difference between the spectrum intensity of the ith trace metal element to be detected under the secondary wavelength j and the spectrum intensity of the main wavelength; a normalized value representing the minimum value in the wavelength difference between the secondary wavelength j of the