CN109211892B - Method for detecting content of residual EDTA in lithium fluoride - Google Patents
Method for detecting content of residual EDTA in lithium fluoride Download PDFInfo
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- CN109211892B CN109211892B CN201811273371.1A CN201811273371A CN109211892B CN 109211892 B CN109211892 B CN 109211892B CN 201811273371 A CN201811273371 A CN 201811273371A CN 109211892 B CN109211892 B CN 109211892B
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
Abstract
The invention relates to a method for detecting the content of residual EDTA in lithium fluoride, which comprises the following steps: s1, preparing a plurality of groups of EDTA standard solutions with different gradient concentrations; s2, respectively adding the EDTA standard solutions with different gradient concentrations into a container in equal volume, adding a reagent D and a reagent E with known concentrations in equal volume into each container, digesting at 150-170 ℃, and cooling; s3, transferring the solution to a cuvette, placing the cuvette into a COD rapid-determination instrument for color comparison, reading the COD value and recording; s4, fitting according to the recorded data to obtain an EDTA concentration-COD value standard curve; s5, preparing a lithium fluoride sample into a sample solution to be detected, replacing the standard solution in the steps S2-S3 with the sample solution to be detected to perform S2-S3 operation, and recording the COD value corresponding to the sample solution to be detected; and S6, substituting the COD value obtained in the step S5 into the standard curve of the step S4 to obtain the concentration of the EDTA in the sample solution to be detected, and calculating the residual quantity of the EDTA in the lithium fluoride sample according to the concentration. The method has the advantages of good measurement repeatability, small relative deviation and low detection limit.
Description
Technical Field
The invention relates to the technical field of chemical quantitative detection and analysis, in particular to a method for detecting the content of residual EDTA in lithium fluoride.
Background
Lithium fluoride is an important lithium-based base material and widely applied in many aspects, and particularly can be used as a raw material for synthesizing lithium hexafluorophosphate (LiPF6) which is most widely applied at present. Lithium fluoride with low metal ion content can be prepared by industrial-grade lithium carbonate through a series of processes, in order to further reduce the content of metal ions in the lithium fluoride, mainly the content of calcium ions, a small amount of EDTA sodium salt is added in the production process to reduce the content of calcium metal ions in the product, but the residual amount of EDTA in the final product needs to be controlled, and the content of residual EDTA can directly influence the quality of the product of the next synthesis process, thereby influencing the usability and safety performance of the battery. Therefore, a quantitative detection method of the residual amount of the chelating agent EDTA is very necessary. Meanwhile, a set of rapid, simple and accurate detection method is established for EDTA (ethylene diamine tetraacetic acid) residual in lithium fluoride, the dosage of EDTA used for removing Ca ions in the process of producing the lithium fluoride is investigated by monitoring and analyzing the EDTA in the lithium fluoride, and meanwhile, an analysis basis is provided for the quality standard of the EDTA residual quantity in the lithium fluoride product under the condition of not influencing the service performance and the safety performance of the lithium battery.
Because the sodium EDTA salt is easily soluble in water, the sodium EDTA salt can perform a complexing reaction with almost all metal ions, but the priority order of the EDTA to perform the complexing reaction with the metal ions is different under different pH values. According to the characteristics of EDTA, EDTA is often used as a chelating agent in the pharmaceutical industry, the food industry, the chemical industry and the like to remove residual metal ions, such as metal ions of Pb, Ca, Cr and the like. At present, trace metal ions such as Cu and Fe in products such as food and medicine can be separated and measured by high performance liquid chromatography through reversed phase ion pair, and the content of the EDTA-Cu or EDTA-Fe chelate can be further calculated. However, for lithium fluoride products with high metal ion content and many types (lithium fluoride contains sodium, potassium, magnesium, calcium, copper, ammonium ions and the like), the residual amount of all EDTA in the lithium fluoride product cannot be detected by adopting high performance liquid chromatography, and at present, no relevant literature report on how to quantitatively detect the residual EDTA in the lithium fluoride product exists.
Disclosure of Invention
Technical problem to be solved
The invention aims to provide a method for detecting the content of residual EDTA in lithium fluoride, which can realize quantitative detection of residual EDTA in a lithium fluoride product and has the characteristics of high analysis efficiency, good repeatability, small relative deviation, low detection limit and the like.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
a method for detecting the content of residual EDTA in lithium fluoride comprises the following steps:
s1, weighing EDTA standard substance, preparing a plurality of groups of EDTA standard solutions with different gradient concentrations;
s2, taking the EDTA standard solutions with different gradient concentrations in equal volume, respectively adding the EDTA standard solutions into a container, adding the reagents D and E with the known concentrations in equal volume into each container, digesting at 150-170 ℃, taking out each container after digestion, and cooling;
s3, transferring the solution in each container to a cuvette, placing the cuvette in a COD rapid-determination instrument for colorimetric reading of COD value, and respectively recording data corresponding to EDTA standard solutions with different gradient concentrations;
s4, fitting according to the data recorded in the step S3 to obtain an EDTA concentration-COD value standard curve;
s5, preparing a lithium fluoride sample into a sample solution to be detected, replacing the EDTA standard solution in the steps S2-S3 with the sample solution to be detected to execute the operations of the steps S2-S3, and recording the COD value corresponding to the sample solution to be detected;
and S6, substituting the COD value obtained in the step S5 into the standard curve obtained in the step S4 to obtain the concentration of the EDTA in the sample solution to be detected, and calculating the residual amount of the EDTA in the lithium fluoride sample according to the concentration.
In a preferred embodiment of the present invention, in step S1, the concentrations of the EDTA standard solutions in the plurality of sets of EDTA standard solutions with different gradient concentrations are varied in integral multiple steps.
In a preferred embodiment of the present invention, in step S1, the concentration of the prepared EDTA standard solution includes five gradient concentrations, i.e., 10mg/L, 50mg/L, 100mg/L, 200mg/L and 1000 mg/L.
In a preferred embodiment of the present invention, in step S2, the container is a test tube, a conical flask or a special digestion flask.
In a preferred embodiment of the present invention, in step S2, the reagent D is an oxidizing agent and the reagent E is a catalyst.
In a preferred embodiment of the present invention, in step S2, the reagent D is a potassium dichromate-mercury sulfate solution, and the reagent E is a sulfuric acid-silver sulfate solution.
In general, the reagent D and the reagent E are sold by manufacturers in cooperation with COD tachymeter, and can be prepared in advance for standby. The COD rapid detector is a COD rapid detector of Lianhua technology, and can detect COD within 20 minutes.
In a preferred embodiment of the invention, in the step S2, digestion is performed by using an intelligent digestion device, wherein the digestion temperature is set to 150-170 ℃, and the digestion time is 8-20 min; preferably, the digestion temperature is set to be 160 ℃ or 165 ℃, and the digestion time is 10-12 min. The intelligent digestion device is a single intelligent digestion device, or the COD rapid-measuring instrument is matched with a self-contained COD digestion device.
The intelligent digestion device is a microcomputer technology for timing control of the heating electric furnace, and can simultaneously perform heating reflux on 5-10 conical flasks or a special digestion flask reflux device.
In a preferred embodiment of the present invention, in step S2, after digestion, each container is taken out, air-cooled for 2-5 min, and cooled to room temperature. So as to avoid the influence of high temperature on the optical system of the COD tachymeter.
In a preferred embodiment of the present invention, step S2 further comprises diluting each container by adding an equal volume of pure water after digestion.
In a preferred embodiment of the present invention, the specific process from step S2 to step S3 is:
sequentially taking 2.5mL of EDTA standard solutions with different gradient concentrations in the step S1 into a digestion container;
adding equal volumes of a reagent D and a reagent E with known concentrations into each container, shaking up, and then putting each container into an intelligent digestion device for digestion for 10 minutes;
after digestion, each vessel was taken out and cooled in air for 2 minutes;
after cooling, 2.5mL of pure water is respectively added into each container and shaken up;
and finally, pouring the solution in each container into a 3cm cuvette, putting the cuvette into a COD (chemical oxygen demand) rapid-measuring instrument for colorimetric reading of COD value, and recording data corresponding to EDTA (ethylene diamine tetraacetic acid) standard solutions with various concentrations.
The basic principle of the invention for EDTA determination is as follows: the invention uses EDTA (ethylene diamine tetraacetic acid) contained in lithium fluoride as a reducing organic matter, dissolves in water to obtain a solution, adds a reagent D and a reagent E into the solution, adds a known amount of potassium dichromate solution, uses silver salt as a catalyst in a strong acid medium, and oxidizes the organic matter after boiling and refluxing, wherein Cr in the potassium dichromate6+Is reduced to Cr3+(this process of oxidation-reduction is referred to asDigestion), and determining Cr by COD rapid detector colorimetry3 +The content of (A) is directly converted into a COD value, and then the concentration of EDTA in a standard cuvette is calculated. Firstly, preparing an EDTA concentration-COD value standard curve by using a standard sample, then preparing a sample solution to be detected by using a lithium fluoride sample, obtaining the COD value of the sample solution to be detected by using the same method, and finding out the corresponding EDTA concentration on the standard curve according to the COD value, so that the residual amount of the EDTA in the lithium fluoride sample can be calculated.
(III) advantageous effects
The invention has the beneficial effects that:
the content of trace components in a substance is measured by using a high performance liquid chromatography, a COD value (COD tachymeter) is usually measured by using a COD detector to detect the amount of oxygen consumed by oxidation of a reducing pollutant in a water body by a strong oxidant, the COD value is used for evaluating the degree of pollution of the water body, and a fresh person is used for quantitatively measuring the residual quantity of EDTA in a solid substance, particularly lithium fluoride. The invention uses a COD rapid detector to quantitatively detect the residual quantity of EDTA in the lithium fluoride for the first time, and can eliminate the interference and influence of various metal ions and different pH values in the lithium fluoride product. Experiments show that the method is feasible, very quick, simple and convenient, the relative standard deviation RSD% is 1.03-2.55%, and the detection limit reaches 10mg/L, so the method has the advantages of good measurement repeatability, small relative deviation, low detection limit and high stability.
Detailed Description
For better understanding of the present invention, the present invention will be described in detail with reference to the following specific examples, which should not be construed as limiting the scope of the present invention.
Example 1
(1) Preparing a COD rapid determinator and an intelligent digester; preparing a reagent D and a reagent E; setting digestion parameters: run at 160 ℃ for 10 min.
(2) Preparing 10, 50, 100, 200 and 1000mg/L EDTA standard solution, and shaking up for later use.
(3) Sequentially taking 2.5mL of EDTA standard solutions with different concentrations into each test tube, adding the reagent D and the reagent E into each test tube in sequence, shaking up, carefully placing the test tubes into a digestion instrument for digestion for 10 minutes, after digestion is completed, carefully taking out the test tubes, placing the test tubes into an air cooling device on a test tube rack for 2 minutes.
(4) After completion of cooling, 2.5mL of ultrapure water was added to each tube and shaken.
(5) And pouring the solution in the test tube into a 3cm cuvette, placing the cuvette into a rapid tester for colorimetric reading of a COD value under a COD gear, and recording experimental data to obtain a COD value corresponding to 5 groups of gradient concentrations. Fitting the COD values with the known EDTA concentration to obtain a standard curve equation of EDTA concentration-COD value, wherein the equation is 0.6915x +8.3557, R2＝0.9991.
(6) Similarly, accurately weighing a certain amount of lithium fluoride sample [ lithium fluoride sample 01 ], adding 2.5mL of water to dissolve the lithium fluoride sample into a sample solution to be detected, and reading COD data corresponding to the sample solution to be detected by referring to the digestion operations in the steps (3) to (4) and the COD determination operation in the step (5); the data are substituted into the standard curve method to obtain the residual content of 502.05ppm in the lithium fluoride product, and the specific data are detailed in table 1.
Example 2
(1) Preparing a COD rapid determinator and an intelligent digester; preparing a reagent D and a reagent E; setting digestion parameters: run at 160 ℃ for 10 min.
(2) Preparing 10, 50, 100, 200 and 1000mg/L EDTA standard solution, and shaking up for later use.
(3) Sequentially taking 2.5mL of EDTA standard solutions with different concentrations into each test tube, adding the reagent D and the reagent E into each test tube in sequence, shaking up, carefully placing the test tubes into a digestion instrument for digestion for 10 minutes, after digestion is completed, carefully taking out the test tubes, placing the test tubes into an air cooling device on a test tube rack for 2 minutes.
(4) After completion of cooling, 2.5mL of ultrapure water was added to each tube and shaken.
(5) And pouring the solution in the test tube into a 3cm cuvette, placing the cuvette into a rapid tester for colorimetric reading of a COD value under a COD gear, and recording experimental data to obtain a COD value corresponding to 5 groups of gradient concentrations. Fitting the COD values with the known EDTA concentration to obtain a standard curve equation of EDTA concentration-COD value, wherein the equation is 0.6915x +8.3557, R2＝0.9991。
(6) Similarly, accurately weighing a certain amount of lithium fluoride sample [ lithium fluoride sample 02 ], adding 2.5mL of water to dissolve the lithium fluoride sample into a sample solution to be detected, and reading COD data corresponding to the sample solution to be detected by referring to the digestion operations in the steps (3) to (4) and the COD determination operation in the step (5); the data are substituted into the standard curve method to obtain the residual content of 508.53ppm in the lithium fluoride product, and the specific data are detailed in table 1.
Example 3
(1) Preparing a COD rapid determinator and an intelligent digester; preparing a reagent D and a reagent E; setting digestion parameters: the operation was carried out at 165 ℃ for 10 min.
(2) Preparing 10, 50, 100, 200 and 1000mg/L EDTA standard solution, and shaking up for later use.
(3) Sequentially taking 2.5mL of EDTA standard solutions with different concentrations into each test tube, adding the reagent D and the reagent E into each test tube in sequence, shaking up, carefully placing the test tubes into a digestion instrument for digestion for 10 minutes, after digestion is completed, carefully taking out the test tubes, placing the test tubes into an air cooling device on a test tube rack for 2 minutes.
(4) After completion of cooling, 2.5mL of ultrapure water was added to each tube and shaken.
(5) And pouring the solution in the test tube into a 3cm cuvette, placing the cuvette into a rapid tester for colorimetric reading of a COD value under a COD gear, and recording experimental data to obtain a COD value corresponding to 5 groups of gradient concentrations. Fitting the COD values with the known EDTA concentration to obtain a standard curve equation of EDTA concentration-COD value, wherein the equation is 0.6915x +8.3557, R2＝0.9991；
(6) Similarly, accurately weighing a certain amount of lithium fluoride sample [ lithium fluoride sample 03 ], adding 2.5mL of water to dissolve the lithium fluoride sample into a sample solution to be detected, and reading COD data corresponding to the sample solution to be detected by referring to the digestion operations in the steps (3) to (4) and the COD determination operation in the step (5); the data were substituted into the standard curve method described above to obtain 55.9ppm of residual content in the lithium fluoride product, with the specific data detailed in table 1.
TABLE 1 Experimental data for residual EDTA content of lithium fluoride samples
The experimental results show that the detection method is very quick, simple and convenient, the relative standard deviation RSD% is 1.03-2.55%, and the detection limit reaches 10mg/L, so that the method has the advantages of good measurement repeatability, small relative deviation, low detection limit and high stability. When the standard sample EDTA is used to prepare the standard solution, the concentration is not limited to five gradient concentrations of 10, 50, 100, 200 and 1000mg/L, and other gradient concentrations can be used, as long as the selected concentration multiple is reasonable.
In addition, in order to improve the detection accuracy, 3-5 standard samples can be prepared for each gradient concentration, the COD value of each group of standard samples read out from the COD tacheometer is averaged to obtain a series of COD values corresponding to different groups of different gradient concentrations, and the COD values are used for fitting an EDTA concentration-COD standard curve to obtain a standard curve equation. The basic principle of the invention for EDTA determination is as follows: dissolving EDTA (ethylene diamine tetraacetic acid) contained in lithium fluoride, which is an organic matter with reducibility, in water to obtain a solution, adding a reagent D and a reagent E into the solution, adding a known amount of potassium dichromate solution, using a silver salt as a catalyst in a strong acid medium, boiling and refluxing, oxidizing the organic matter, and oxidizing Cr in the potassium dichromate6+Is reduced to Cr3+(this redox process is called digestion), and Cr is measured by COD rapid-speed analyzer colorimetry3+The content of (A) is directly converted into a COD value, and then the concentration of EDTA in a standard cuvette is calculated. Firstly, preparing an EDTA concentration-COD value standard curve by using a standard sample, then preparing a sample solution to be detected by using a lithium fluoride sample, obtaining the COD value of the sample solution to be detected by using the same method, and finding out the corresponding EDTA concentration on the standard curve according to the COD value, so that the residual amount of the EDTA in the lithium fluoride sample can be calculated.
The invention uses a COD rapid detector to quantitatively detect the residual quantity of EDTA in the lithium fluoride, can eliminate the interference and influence of various metal ions and different pH values in the lithium fluoride product, and has the advantages of good repeatability, small relative deviation, high stability, low detection limit and the like. In conclusion, the present invention can be used as a standard detection means for the residual amount of EDTA in lithium fluoride as an electrolyte raw material.
Claims (11)
1. A method for detecting the content of residual EDTA in lithium fluoride is characterized by comprising the following steps:
s1, weighing EDTA standard substance, preparing a plurality of groups of EDTA standard solutions with different gradient concentrations;
s2, taking the EDTA standard solutions with different gradient concentrations in equal volume, respectively adding the EDTA standard solutions into a container, adding the reagents D and E with the known concentrations in equal volume into each container, digesting at 150-170 ℃, taking out each container after digestion, and cooling;
s3, transferring the solution in each container to a cuvette, placing the cuvette in a COD rapid-determination instrument for colorimetric reading of COD value, and respectively recording data corresponding to EDTA standard solutions with different gradient concentrations;
s4, fitting according to the data recorded in the step S3 to obtain an EDTA concentration-COD value standard curve;
s5, preparing a lithium fluoride sample into a sample solution to be detected, replacing the EDTA standard solution in the steps S2-S3 with the sample solution to be detected to execute the operations of the steps S2-S3, and recording the COD value corresponding to the sample solution to be detected;
and S6, substituting the COD value obtained in the step S5 into the standard curve obtained in the step S4 to obtain the concentration of the EDTA in the sample solution to be detected, and calculating the residual amount of the EDTA in the lithium fluoride sample according to the concentration.
2. The method for detecting according to claim 1, wherein in step S1, the concentrations of the EDTA standard solutions with different gradient concentrations are varied in integral multiple gradients.
3. The detection method according to claim 1, wherein in step S1, the concentration of the prepared EDTA standard solution includes five gradient concentrations of 10mg/L, 50mg/L, 100mg/L, 200mg/L and 1000 mg/L.
4. The detection method according to claim 1, wherein in step S2, the container is a test tube, a conical flask or a special digestion bottle.
5. The detection method according to claim 1, wherein in step S2, the reagent D is an oxidizing agent and the reagent E is a catalyst.
6. The detection method according to claim 5, wherein in step S2, the reagent D is a potassium dichromate-mercury sulfate solution, and the reagent E is a sulfuric acid-silver sulfate solution.
7. The detection method according to claim 1, wherein in the step S2, digestion is carried out by using an intelligent digestion device, wherein the digestion temperature is set to be 150-170 ℃, and the digestion time is 8-20 min.
8. The detection method according to claim 7, characterized in that: the digestion temperature is set to be 160 ℃ or 165 ℃, and the digestion time is 10-12 min.
9. The detection method according to claim 1, wherein in step S2, after digestion is completed, each container is taken out, air-cooled for 2-5 min, and cooled to room temperature for later use.
10. The detection method according to claim 1, wherein the step S2 further comprises diluting the sample by adding an equal volume of pure water to each vessel after digestion.
11. The detection method according to claim 2, wherein the specific process from step S2 to step S3 is as follows:
sequentially taking 2.5mL of EDTA standard solutions with different gradient concentrations in the step S1 into a digestion container;
adding equal volumes of a reagent D and a reagent E with known concentrations into each container, shaking up, and then putting each container into an intelligent digestion device for digestion for 10 minutes;
after digestion, each vessel was taken out and cooled in air for 2 minutes;
after cooling, 2.5mL of pure water is respectively added into each container and shaken up;
and finally, pouring the solution in each container into a 3cm cuvette, putting the cuvette into a COD (chemical oxygen demand) rapid-measuring instrument for colorimetric reading of COD value, and recording data corresponding to EDTA (ethylene diamine tetraacetic acid) standard solutions with various concentrations.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101498721A (en) * | 2009-03-04 | 2009-08-05 | 中国检验检疫科学研究院 | Colloidal-gold strip measuring method and detection system |
| JP2010085344A (en) * | 2008-10-02 | 2010-04-15 | Miura Co Ltd | Quantitative method of chloride ion |
| CN102636485A (en) * | 2012-03-28 | 2012-08-15 | 云南磷化集团有限公司 | Method for measuring content of calcium oxide in iron ores |
| CN104267124A (en) * | 2014-10-13 | 2015-01-07 | 中国检验认证集团宁波有限公司 | Method for detecting EDTA (ethylene diamine tetraacetic acid) in laundry detergent |
| CN104817155A (en) * | 2014-01-30 | 2015-08-05 | 株式会社岛津制作所 | Method for immediate treatment of waste liquid generated in on-line detection of chemical oxygen demand through a dichromate method |
-
2018
- 2018-10-30 CN CN201811273371.1A patent/CN109211892B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010085344A (en) * | 2008-10-02 | 2010-04-15 | Miura Co Ltd | Quantitative method of chloride ion |
| CN101498721A (en) * | 2009-03-04 | 2009-08-05 | 中国检验检疫科学研究院 | Colloidal-gold strip measuring method and detection system |
| CN102636485A (en) * | 2012-03-28 | 2012-08-15 | 云南磷化集团有限公司 | Method for measuring content of calcium oxide in iron ores |
| CN104817155A (en) * | 2014-01-30 | 2015-08-05 | 株式会社岛津制作所 | Method for immediate treatment of waste liquid generated in on-line detection of chemical oxygen demand through a dichromate method |
| CN104267124A (en) * | 2014-10-13 | 2015-01-07 | 中国检验认证集团宁波有限公司 | Method for detecting EDTA (ethylene diamine tetraacetic acid) in laundry detergent |
Non-Patent Citations (1)
| Title |
|---|
| 电镀废水中络合物对化学需氧量测定的影响;刘晓星等;《电镀与精饰》;20110331;第33卷(第3期);第41-44页 * |
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Inventor after: Zhao Jingwei Inventor after: Cheng Zeying Inventor after: Yin Songnan Inventor after: Xin Yong Inventor before: Zhao Jingwei Inventor before: Cheng Zeying Inventor before: Yin Songnan Inventor before: Xin Yong |