Method for rapidly testing content of calcium hydroxide

Abstract

The invention discloses a method for rapidly testing the content of calcium hydroxide. The method comprises the following steps: S1, providing a hydrochloric acid standard solution and a triethylamine standard solution; s2, weighing a to-be-detected sample, dissolving the to-be-detected sample in the hydrochloric acid standard solution, and stirring until the solution is transparent and clear to obtain a first solution; and placing the first solution on an automatic potentiometric titrator, titrating the obtained triethylamine standard solution into the first solution by using the automatic potentiometric titrator, and reading a test result of the content of calcium hydroxide until a first jump point is reached. The method for rapidly testing the content of calcium hydroxide can be used for rapidly and accurately testing the content of calcium hydroxide.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, in particular to a rapid testing method for calcium hydroxide content. Background Art

[0002] During the production and manufacturing process of lithium-ion batteries, calcium compounds may be introduced into lithium-ion batteries due to various reasons, such as the introduction of raw materials, the introduction of the production environment and equipment, and contamination during storage and transportation, forming calcium hydroxide. The presence of calcium hydroxide can have negative effects, such as affecting the performance of electrode materials, destroying the stability of the electrolyte, increasing the internal resistance of the battery, or affecting the safety of the battery. In the prior art, the test of calcium hydroxide refers to the national standard GB 1886.374 and utilizes the principle of acid-base reaction. Hydrochloric acid is used to titrate calcium hydroxide, and phenolphthalein is used as an indicator. The indicator is used to identify the reaction endpoint, and the calcium hydroxide content is calculated based on the volume of hydrochloric acid consumed. However, on the one hand, the indicator method uses a manual burette titration method, and there is a case of over-titration for endpoint determination, resulting in poor consistency of test results; on the other hand, calcium hydroxide has low solubility, and adding sucrose may not complete dissolution, making it impossible to accurately titrate the calcium hydroxide content.

[0003] Therefore, it is very necessary to provide a method for testing the content of calcium hydroxide quickly and accurately. Summary of the Invention

[0004] The object of the present invention is to solve the above problems and provide a rapid testing method for calcium hydroxide content, which can quickly and accurately test the content of calcium hydroxide.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A rapid testing method for calcium hydroxide content comprises the following steps:

[0007] S1. Provide hydrochloric acid standard solution and triethylamine standard solution;

[0008] S2. Weigh the sample to be tested, dissolve the sample to be tested in the hydrochloric acid standard solution, and stir until the solution is transparent and clear to obtain a first solution; place the first solution on an automatic potentiometric titrator, and use the automatic potentiometric titrator to titrate the obtained triethylamine standard solution into the first solution until the first jump point is reached, and then read the test result of the calcium hydroxide content.

[0009] Optionally, the preparation of the hydrochloric acid standard solution and the preparation of the triethylamine standard solution in step S1 and the preparation of the first solution in step S2 are all performed using the automatic potentiometric titrator.

[0010] Optionally, in step S1, the concentrations of the hydrochloric acid standard solution and the triethylamine standard solution are both 0.1 mol / L.

[0011] Optionally, step S2 includes the steps of: weighing 0.1 g of the sample to be tested, dissolving the sample to be tested in 50 mL of the hydrochloric acid standard solution, and stirring until the solution becomes transparent and clear to obtain a first solution; at the same time, using 50 mL of the hydrochloric acid standard solution as a blank sample; placing the blank sample and the first solution on the automatic potentiometric titrator respectively, and setting a calculation formula; using the automatic potentiometric titrator to titrate the obtained triethylamine standard solution into the first solution until the first sudden jump endpoint is reached, and then reading the test result of the calcium hydroxide content.

[0012] Optionally, the calculation formula set on the automatic potentiometric titrator is:

[0013]

[0014] Wherein, X is the content of calcium hydroxide in the sample to be tested, %;

[0015] C1 is the concentration of standard hydrochloric acid solution, 0.1 M;

[0016] V1 is the volume of the standard hydrochloric acid solution added to the first solution, 50 mL;

[0017] C2 is the concentration of standard triethylamine solution, 0.1 M;

[0018] V2 is the volume of the standard triethylamine solution titrated into the first solution, mL;

[0019] V0 is the volume of triethylamine standard solution consumed in the blank sample, mL;

[0020] M is the mass of the sample to be tested, g.

[0021] Optionally, in step S1, the preparation method of the hydrochloric acid standard solution includes the steps of: taking 9 mL of hydrochloric acid, adding it to 1000 mL of pure water, shaking it to obtain a second solution, and placing the second solution in the automatic potentiometric titrator; weighing 0.11-0.15 g of standard anhydrous sodium carbonate burned to constant weight at 270-300°C, weighing it to 0.00002 g, dissolving it in 50 mL of water, stirring it to completely dissolve it, and obtaining a third solution, using an automatic potentiometric titrator to titrate the third solution into the second solution, titrating to the first sudden end point, until the automatic potentiometric titrator displays the required concentration of the hydrochloric acid standard solution.

[0022] Optionally, in step S1, the preparation method of the triethylamine standard solution includes the steps of: taking 1 g of triethylamine, adding it to 1000 mL of diethyl carbonate, to obtain a fourth solution; weighing 0.1±0.0001 g of potassium hydrogen phthalate, dissolving it in 50 mL of pure water, and stirring it to completely dissolve it, to obtain a fifth solution; using the automatic potentiometric titrator to titrate the fifth solution into the fourth solution until the first jump endpoint is reached, until the automatic potentiometric titrator displays the required triethylamine standard concentration.

[0023] Optionally, the automatic potentiometric titrator includes the Metrohm automatic potentiometric titrator 888.

[0024] The beneficial effects produced by the present invention include at least:

[0025] The rapid testing method for calcium oxide content of the present invention has the advantages that, on the one hand, an operation process is carried out by adopting an automatic potentiometric titrator, and the endpoint of the reaction is determined according to the potential jump of the reaction endpoint solution through automatic potentiometric titration, thereby avoiding errors caused by manual operation, being able to sensitively detect the titration endpoint, and ensuring the consistency of the test results. The method is simple to operate, has low requirements on personnel skills, and has high parallelism and stability of the test results. On the other hand, calcium hydroxide is first dissolved with excess hydrochloric acid, and then titrated with a triethylamine standard solution, thereby ensuring that the calcium hydroxide in the sample to be tested can be completely dissolved, and improving the accuracy of the test. DETAILED DESCRIPTION

[0026] To facilitate understanding of the present invention, preferred embodiments of the present invention are provided below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] In the present invention, descriptions such as “first”, “second”, etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features.

[0029] It should be noted that, unless otherwise specified, the raw materials involved in the present invention can be obtained from suppliers known in the art or prepared by known methods.

[0030] Example 1: The present invention provides a rapid testing method for calcium hydroxide content, comprising the steps of:

[0031] S1. Provide hydrochloric acid standard solution and triethylamine standard solution;

[0032] S2. Weigh the sample to be tested, dissolve the sample to be tested in the hydrochloric acid standard solution, and stir until the solution is transparent and clear to obtain a first solution; place the first solution on an automatic potentiometric titrator, and use the automatic potentiometric titrator to titrate the obtained triethylamine standard solution into the first solution until the first jump point is reached, and then read the test result of the calcium hydroxide content.

[0033] The rapid testing method for calcium oxide content of the present invention has the advantages that, on the one hand, an operation process is carried out by adopting an automatic potentiometric titrator, and the endpoint of the reaction is determined according to the potential jump of the reaction endpoint solution through automatic potentiometric titration, thereby avoiding errors caused by manual operation, being able to sensitively detect the titration endpoint, and ensuring the consistency of the test results. The method is simple to operate, has low requirements on personnel skills, and has high parallelism and stability of the test results. On the other hand, calcium hydroxide is first dissolved with excess hydrochloric acid, and then titrated with a triethylamine standard solution, thereby ensuring that the calcium hydroxide in the sample to be tested can be completely dissolved, and improving the accuracy of the test.

[0034] Optionally, the preparation of the hydrochloric acid standard solution and the triethylamine standard solution in step S1 and the preparation of the first solution in step S2 are all carried out using the automatic potentiometric titrator; the concentrations of the hydrochloric acid standard solution and the triethylamine standard solution are both 0.1 mol / L.

[0035] Step S2 includes the following steps: weighing 0.1 g of the sample to be tested, accurate to 0.0001 g, and adding the weighed amount to a 150 mL beaker; dissolving the sample to be tested in 50 mL of the hydrochloric acid standard solution, stirring until the solution becomes transparent and clear, to obtain a first solution; simultaneously using 50 mL of the hydrochloric acid standard solution as a blank sample; placing the blank sample and the first solution on the automatic potentiometric titrator, respectively, and setting a calculation formula; using the automatic potentiometric titrator to titrate the obtained triethylamine standard solution into the first solution until the first sudden end point is reached, and then reading the test result of the calcium hydroxide content.

[0036] The calculation formula set on the automatic potentiometric titrator is:

[0037] Where,

[0038] X is the content of calcium hydroxide in the sample to be tested, %;

[0039] C1 is the concentration of standard hydrochloric acid solution, 0.1 M;

[0040] V1 is the volume of the standard hydrochloric acid solution added to the first solution, 50 mL;

[0041] C2 is the concentration of standard triethylamine solution, 0.1 M;

[0042] V2 is the volume of the standard triethylamine solution titrated into the first solution, mL;

[0043] V0 is the volume of triethylamine standard solution consumed in the blank sample, mL;

[0044] M is the mass of the sample to be tested, g.

[0045] In step S1, the preparation method of the hydrochloric acid standard solution includes the following steps: taking 9 mL of hydrochloric acid, adding it to 1000 mL of pure water, shaking it to obtain a second solution, placing the second solution in the automatic potentiometric titrator, using a 1 / 100,000 balance to weigh 0.11-0.15 g of standard anhydrous sodium carbonate burned to constant weight at 270-300 ° C, accurate to 0.00002 g, dissolving it in 50 mL of water, stirring it to completely dissolve it, and obtaining a third solution, using an automatic potentiometric titrator to titrate the third solution into the second solution, titrating to the first sudden end point, until the automatic potentiometric titrator displays the required hydrochloric acid standard solution concentration.

[0046] In step S1, the preparation method of the triethylamine standard solution includes the following steps: taking 1 g of triethylamine, adding it to 1000 mL of diethyl carbonate, shaking it well, and pouring it into a reagent bottle of a Wantong automatic potentiometric titrator 888 to obtain a fourth solution; weighing 0.1±0.0001 g of potassium hydrogen phthalate, dissolving it in 50 mL of pure water, and stirring it to completely dissolve it to obtain a fifth solution; using the automatic potentiometric titrator to titrate the fifth solution into the fourth solution until the first sudden end point is reached, until the automatic potentiometric titrator displays the required triethylamine standard concentration.

[0047] The automatic potentiometric titrator described in the embodiment of the present invention is a Wantong automatic potentiometric titrator 888.

[0048] Example 2: Three samples to be tested were selected respectively, and the calcium hydroxide in the three samples was tested using the rapid testing method for calcium hydroxide of the present invention. Each sample to be tested was tested three times. The test results are shown in Table 1.

[0049] Sample 1 Calcium hydroxide content / wt% 1st time 98.9857 2nd time 98.9855 3rd time 98.9868 average value 98.9860 Extremely poor 0.0013 Sample 2 Calcium hydroxide content / wt% 1st time 99.2454 2nd time 99.2469 3rd time 99.2472 average value 99.2465 Extremely poor 0.0018 Sample 3 Calcium hydroxide content / wt% 1st time 99.0150 2nd time 99.0182 3rd time 99.0166 mean 99.0166 Extremely poor 0.0032

[0050] As shown in Table 1, the sodium hydroxide in the sample to be tested is tested by the rapid test method for calcium hydroxide content of the present invention. The content of calcium hydroxide is quickly determined, and the test results obtained are consistent and stable.

[0051] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above embodiments merely represent preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A rapid testing method for calcium hydroxide content, characterized in that, Including steps: S1. Provide hydrochloric acid standard solution and triethylamine standard solution; S2. Weigh the sample to be tested, dissolve the sample in the hydrochloric acid standard solution, and stir until the solution becomes transparent and clear to obtain a first solution; The first solution is placed on an automatic potentiometric titrator, and the obtained triethylamine standard solution is titrated into the first solution using the automatic potentiometric titrator until a first jump point is reached, and then a test result of the calcium hydroxide content is read.

2. The rapid testing method according to claim 1, characterized in that The preparation of the hydrochloric acid standard solution and the triethylamine standard solution in step S1 and the preparation of the first solution in step S2 are all performed using the automatic potentiometric titrator.

3. The rapid testing method according to claim 2, characterized in that In step S1, the concentrations of the hydrochloric acid standard solution and the triethylamine standard solution are both 0.1 mol / L.

4. The rapid testing method according to claim 3, characterized in that: Step S2 includes the following steps: weighing 0.1 g of a sample to be tested, dissolving the sample to be tested in 50 mL of the hydrochloric acid standard solution, and stirring until the solution becomes transparent and clear to obtain a first solution; simultaneously, using 50 mL of the hydrochloric acid standard solution as a blank sample; placing the blank sample and the first solution on the automatic potentiometric titrator respectively, setting a calculation formula; and using the automatic potentiometric titrator to titrate the obtained triethylamine standard solution into the first solution until the first sudden end point is reached, and then reading the test result of the calcium hydroxide content.

5. The rapid testing method according to claim 4, characterized in that: The calculation formula set on the automatic potentiometric titrator is: Wherein, X is the content of calcium hydroxide in the sample to be tested, %; C1 is the concentration of standard hydrochloric acid solution, 0.1 M; V1 is the volume of the standard hydrochloric acid solution added to the first solution, 50 mL; C2 is the concentration of standard triethylamine solution, 0.1 M; V2 is the volume of the standard triethylamine solution titrated into the first solution, mL; V0 is the volume of triethylamine standard solution consumed in the blank sample, mL; M is the mass of the sample to be tested, g.

6. The rapid testing method according to claim 3, characterized in that: In step S1, the preparation method of the hydrochloric acid standard solution includes the following steps: taking 9 mL of hydrochloric acid, adding it to 1000 mL of pure water, shaking it to obtain a second solution, and placing the second solution in the automatic potentiometric titrator; weighing 0.11-0.15 g of standard anhydrous sodium carbonate burned to constant weight at 270-300 ° C, weighing it to 0.00002 g, dissolving it in 50 mL of water, stirring it until it is completely dissolved, and obtaining a third solution, using an automatic potentiometric titrator to titrate the third solution into the second solution, titrating to the first sudden end point, until the automatic potentiometric titrator displays the required hydrochloric acid standard solution concentration.

7. The rapid testing method according to claim 3, characterized in that: In step S1, the preparation method of the triethylamine standard solution includes the following steps: taking 1 g of triethylamine, adding it to 1000 mL of diethyl carbonate, to obtain a fourth solution; weighing 0.1±0.0001 g of potassium hydrogen phthalate, dissolving it in 50 mL of pure water, and stirring it to completely dissolve it, to obtain a fifth solution; using the automatic potentiometric titrator, titrating the fifth solution into the fourth solution until the first sudden end point is reached, until the automatic potentiometric titrator displays the required triethylamine standard concentration.

8. The rapid testing method according to claim 1, characterized in that: The automatic potentiometric titrator includes the Metrohm automatic potentiometric titrator 888.

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