CN-119199010-B - Method for detecting purity of battery-grade lithium salt

CN119199010BCN 119199010 BCN119199010 BCN 119199010BCN-119199010-B

Abstract

The application discloses a method for detecting the purity of battery-grade lithium salt, which comprises the steps of weighing the lithium salt, placing the lithium salt in a conical flask, stirring and dissolving, adding a dropwise methyl red-bromocresol green indicator into a first solution to be detected, titrating the solution to be detected into a wine red color by using a hydrochloric acid standard titration solution, adding a phenolphthalein indicator into a second solution to be detected for titrating, adding the methyl red-bromocresol green indicator into the solution to be detected, titrating the solution to be detected into the wine red color, and finally calculating the purity percentage of the lithium salt. The detection method can be effectively used for the analysis and detection of battery-level lithium carbonate, lithium hydroxide monohydrate and lithium oxide, and is less in sample consumption and hydrochloric acid consumption and more environment-friendly compared with the traditional method, meanwhile, the influence of hydrochloric acid consumption of carbonate ions in the traditional national standard can be effectively solved, the detection accuracy is further improved, and meanwhile, the method can be effectively used for the analysis and detection of battery-level lithium oxide.

Inventors

ZHANG WEIMIN
CHEN XIAOBO
ZHU FAJUN
WANG YANWEI

Assignees

深圳博粤新材料科技有限公司

Dates

Publication Date: 20260508
Application Date: 20241008

Claims (1)

1. The method for detecting the purity of the battery-grade lithium salt is characterized by comprising the following specific steps of: S1, respectively weighing lithium salt with the mass of m 1 、m 2 into a conical flask, and carrying out parallel sample and blank experiments, adding V 0 mL of deionized water, adding a rubber plug, and stirring for dissolution to obtain a first solution to be tested and a second solution to be tested; s2, adding a methyl red-bromocresol green indicator into the first solution to be tested, changing the green color into the reddish wine color by using a hydrochloric acid standard titration solution with the molar concentration of c 1 , boiling for two minutes, removing carbon dioxide, cooling, continuing titration until the reddish wine color is the end point, and recording the consumption volume V 1 of the hydrochloric acid standard titration solution; s3, adding a phenolphthalein indicator into the second solution to be detected, and titrating to light red by using hydrochloric acid solution with the molar concentration of c 0 under the condition of isolating with air, and recording no reading; S4, titrating by using a hydrochloric acid standard titration solution with the molar concentration of c 2 until the solution is colorless, and recording no reading; S5, adding a methyl red-bromocresol green indicator, continuously titrating to a reddish wine by using a hydrochloric acid standard titration solution with the molar concentration of c 2 , boiling for two minutes, cooling, taking the reddish wine as an end point, and recording the consumption volume V 3 of the hydrochloric acid standard titration solution with the molar concentration of c 2 ; s6, calculating the total alkalinity a of the first solution to be measured, namely the content of LiOH+Li 2 CO 3 in the solution, according to the consumption volume V 1 and the hydrochloric acid with the molar concentration of c 1 , calculating the carbonate ion content b of the second solution to be measured, namely the content of Li 2 CO 3 in the sample, according to the consumption volume V 3 and the hydrochloric acid with the molar concentration of c 2 , and finally calculating the purity percentage of lithium salt; in the step S1, the main component of the lithium salt for testing is called to contain anhydrous lithium hydroxide and lithium carbonate, or lithium hydroxide monohydrate and lithium carbonate, or lithium oxide and lithium carbonate; In the step S6, the content calculation formula of carbonate ions and lithium carbonate is as follows: , Wherein c 2 -is hydrochloric acid standard titration solution in the step S5, and the unit is mol/L; m 2 - -the mass of the sample in the second solution to be measured in g; -carbonate ion content in the sample; The volume V of the standard titration solution of hydrochloric acid with the concentration c1 consumed by the carbonate in the step S2 satisfies the following formula: ; The content of hydroxyl ions can be calculated, and the calculation formula is as follows: ; when the main component is anhydrous lithium hydroxide, the calculation formula is as follows: ; When the main component is lithium hydroxide monohydrate, the calculation formula is as follows: ; when the main component is lithium oxide, the calculation formula is: 。

Description

Method for detecting purity of battery-grade lithium salt Technical Field The invention relates to the field of battery material detection, in particular to a method for detecting the purity of battery-grade lithium salt. Background In recent years, the high-technology, high-added-value and green-transformation-leading product markets represented by lithium batteries are exploded, and the requirements of the battery markets in two years can exceed 2TWh and reach more than 6TWh by 2030 from the view of related industry data. At that time, the performance, cost and technical requirements for the product are only getting higher and higher. Lithium electrochemical power, energy conservation and high speed will be the trend of future lithium batteries. As an important component in the new energy field, the development of the lithium battery industry is rapid, the lithium battery industry becomes a new investment focus in the manufacturing field, lithium battery enterprises build new factories in a dispute manner, hope to increase the productivity, and win the price by means of scale effect. The energy saving and high speed of lithium battery manufacturing have become a new industry trend. The battery-grade anhydrous lithium hydroxide, the lithium hydroxide monohydrate and the lithium oxide are all lithium compounds, are in the midstream smelting processing link of the lithium battery industry chain, are important lithium source sources of lithium batteries, and have huge market models. Therefore, the quality control is particularly important, and the purity indexes of the battery-grade anhydrous lithium hydroxide, the lithium hydroxide monohydrate and the lithium oxide are key factors for evaluating the quality of products, are also key detection items of product acceptance links, and have great significance in rapidly and accurately detecting the purity of the battery-grade anhydrous lithium hydroxide, the lithium hydroxide monohydrate and the lithium oxide. According to GB/T1568-2022 lithium hydroxide anhydrous at battery level and GB/T26008-2020 lithium hydroxide monohydrate at battery level, the main contents are lithium hydroxide and lithium carbonate, the other impurity contents are very trace and are all at ppm level, and according to YS/T968-2014 lithium oxide at battery level, the main contents are lithium oxide and lithium carbonate, there is a possibility that part of lithium hydroxide which is not converted in the sintering process or lithium hydroxide generated by absorbing moisture in the production process remains, and the other impurity contents are also very trace and are all at ppm level. At present, the anhydrous lithium hydroxide and lithium hydroxide monohydrate purity analysis method is commonly adopted in GB/T11064.2-2013 lithium carbonate, lithium hydroxide monohydrate and lithium chloride chemical analysis method 2 part, namely acid-base titration method for measuring lithium hydroxide content, and in GB/T11064.2-2013, the influence of carbonate ions is not considered, so that the consumption of hydrochloric acid in the titration process is larger, and the result is often higher. The purity detection of the battery-grade lithium oxide is free from related industry standards and national standards, so that a detection method capable of meeting the approval of both supply and demand parties and improving the detection accuracy is urgently needed in the market. Disclosure of Invention In view of the above problems, the present invention aims to provide a method for detecting the purity of a battery-grade lithium salt capable of eliminating the influence of carbonate ions. In order to achieve the technical purpose, the invention adopts the scheme that the method for detecting the purity of the battery-grade lithium salt comprises the following specific steps: S1, respectively weighing lithium salt with the mass of m 1、m2 into a conical flask, and carrying out parallel sample and blank experiments, adding V 0 mL of deionized water, adding a rubber plug, and stirring for dissolution to obtain a first solution to be tested and a second solution to be tested; S2, adding a methyl red-bromocresol green indicator into the first solution to be tested, changing the hydrochloric acid standard titration solution with the molar concentration of c 1 from green to reddish wine, boiling for two minutes, removing carbon dioxide, cooling, continuing to titrate until the reddish wine is the end point, recording the consumption volume V 1 of the hydrochloric acid standard titration solution, and recording the consumption volume V 2 of the hydrochloric acid standard titration solution of a blank sample along with a blank experiment; S3, adding a phenolphthalein indicator into the second solution to be detected, and titrating to light red by using hydrochloric acid solution with the molar concentration of c 2 under the condition of isolating with air, and recording no reading; S4, titrating by using a hydrochlor