CN111289686A - Method for measuring content of residual alkali in solution and application thereof - Google Patents
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention discloses a method for measuring the content of residual alkali in a solution and application thereof. The method includes preparing a mixed indicator solution; titrating the sample solution by using a hydrochloric acid solution; and calculating the content of residual alkali in the sample solution. Compared with the traditional phenolphthalein-methyl orange method, the method provided by the invention is simpler and more convenient to operate, and the test result is more accurate.
Description
Technical Field
The invention relates to the technical field of analytical chemistry, in particular to a method for measuring the content of residual alkali in a solution and application thereof.
Background
The lithium ion battery is a new favorite of the secondary battery in the current era due to the outstanding energy density, excellent cycle efficiency and rate charge-discharge efficiency. The power-saving control system is widely applied to a 3C platform at first, and with the maturity of technology and the reduction of cost, the excellent output power of the power-saving control system enables the popularization of electric vehicles, and also opens the way of clean energy, thereby having high economic benefit and environmental protection significance. In the production of lithium battery electrode materials (such as NCM ternary positive electrode materials, lithium titanate positive and negative electrode materials, lithium manganate positive electrode materials), the final products all contain a heterogeneous phase of lithium carbonate or lithium hydroxide due to the ingredients and the process. Heterophasic carbonates and hydroxides are collectively referred to within the industry as residual alkali.
The residual alkali is different from other impurities which have no influence on the material performance, but is harmful impurities which influence various physical properties of the electrode material product. Too high amount of residual alkali affects the processability of the electrode material powder, for example, the homogenization is difficult, the coating is not uniform, the powder falls off after smearing, etc. Meanwhile, the electrical property of the battery is influenced, lithium ion defects are generated, the electron transmission efficiency is reduced, and the internal resistance of the battery is increased. More noteworthy, the amount of residual alkali directly affects the safety performance of the product, and the residual carbonate impurities can be decomposed under the high pressure of the battery to generate carbon dioxide gas, so that the battery expands, the internal structure of the battery is damaged, the battery is short-circuited, a protection circuit fails, and further fire hazards and the like are caused.
The content of carbonate and bicarbonate in the solution is generally tested by a classical double-indicator method, see GB/T11064-2013 method for measuring the content of carbonate in the 12 th part in chemical analysis method of lithium carbonate, lithium hydroxide monohydrate and lithium chloride. In the classical scheme, phenolphthalein is used to indicate the end of the reaction for the acid titration of carbonate to complete conversion to bicarbonate (pH 8.2), and methyl orange is used to indicate the end of the reaction for the acid titration of bicarbonate to molecular carbonate (pH 4.2). Phenolphthalein is used for acid titration, the indicating result is not accurate, the color change range of methyl orange is not obvious, and the actual error is larger because the sample to be detected contains a buffer component.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for determining the residual alkali content of a solution, said method comprising the steps of:
(1) preparing a mixed indicator solution: preparing 1g/L methyl orange solution, 1g/L cresol red solution and 2g/L methylene blue solution with certain volumes respectively; mixing a methyl orange solution, a cresol red solution and a methylene blue solution in a certain volume ratio to obtain a mixed indicator;
(2) titration of the sample solution with hydrochloric acid solution: adding a certain volume of the mixed indicator into a conical flask containing a sample solution, wherein the solution is changed into semitransparent purple black, placing the conical flask on an iron stand, titrating by using an acid burette while shaking, preferably completely developing color of each drop of acid solution until the solution is changed into grass green after titration and shaking, and recording the volume V1 of consumed hydrochloric acid;
zeroing an acid burette;
continuing to slowly titrate until the sample solution changes from grass green to orange, and recording the volume of hydrochloric acid consumed at the moment as V2;
(3) calculating the residual alkali content in the sample solution:
hydroxyl radical mass fraction A in sample solution1＝17.01c(V1-V2)/m×1000，ppm
Carbonate mass fraction A in the sample solution2＝60.02cV2/m×1000，ppm
Total residual alkali amount A in sample solution0＝A1+A2，ppm
Wherein c is the molar concentration of the prepared hydrochloric acid, mol/L; m is the weighed sample mass, g.
Further, the methyl orange solution is prepared by the following method: dissolving 100mg of methyl orange solid in 100mL of water, heating and stirring the solution for 10min by using a constant-temperature magnetic stirrer until the methyl orange solid is completely dissolved, and placing the solution into a 100mL reagent bottle for later use.
Further, the preparation method of the cresol red solution comprises the following steps: dissolving 100mg of cresol red solid in 50mL of ethanol, shaking up, diluting to 100mL, mixing uniformly, and placing into a 100mL reagent bottle for later use.
Further, the preparation method of the methylene blue solution is as follows: 100mg of methylene blue solid is dissolved in 50mL of water, and the dissolved methylene blue solid is placed into a 50mL reagent bottle for standby.
Further, the volume ratio of the methyl orange solution, the cresol red solution and the methylene blue solution in the mixed indicator is 5: 4: 1.
further, the volume of methyl orange solution in the mixed indicator is 40mL, the volume of methylene blue solution is 8mL, and the volume of cresol red solution is 32 mL.
Further, the specific operation method of the zero-setting acid burette comprises the following steps: and (3) taking excessive hydrochloric acid by using a pipette, adding the excessive hydrochloric acid into the burette to enable the liquid level of the acid liquid to rise to be above a zero mark line, fixing the burette on a burette clamp of an iron stand, placing a small beaker for containing waste liquid below the burette, looking up the scale line, and slowly discharging the acid liquid to enable the lowest part of the concave liquid level of the acid liquid in the burette to be equal to the zero mark line of the burette.
Further, the molar concentration of hydrochloric acid was 0.05 mol/L.
Further, 10 drops of the mixing indicator were added to the Erlenmeyer flask containing the sample wash.
The application of the method for measuring the content of residual alkali in the solution in the detection of the battery material also comprises the step of processing a battery material sample before the detection of the content of residual alkali in the battery material.
Further, the battery material sample processing method comprises the following steps: 10g of a battery material sample which is just subjected to a sintering process is taken by using a medicine spoon and placed on a watch glass, and the watch glass is placed in the air for 40 minutes; taking one 100mL beaker, dissolving the battery material sample in 60mL tertiary water, and stirring for 3 minutes by using a magnetic stirrer;
and (3) taking out the magnetic stirrer, performing suction filtration on the washed and uniformly mixed sample by using a Buchner funnel and filter paper, taking a small amount of filtrate to clean the wall of the funnel, filtering again, repeating the process for three times, and pouring the filtrate into a 250mL conical flask for later use.
The invention has the beneficial effects that: the method has the advantages of simple and convenient experimental operation, more accurate experimental data, smaller error and higher stability; the method can be applied to the detection of the content of residual alkali in the battery material, and provides an accurate chemical detection method for the quality inspection link of the battery material.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments.
The preparation and use of the mixed solution of standard sodium hydroxide and sodium carbonate with different proportions verify the feasibility and the error range of the detection method.
The residual alkali content of the ternary powder produced by industry is generally in the range of 1000ppm to 10000ppm, and seven groups of control tests are designed according to the total residual alkali content of 6000 ppm.
Wherein OH in theoretical residual alkali of each group-With CO3 2-The mass fraction ratio of the compounds is 0:6000, 1000:5000, 2000:4000, 3000:3000, 4000:2000, 5000:1000 and 6000:0, and the seven groups are named as A group to G group respectively according to the experiments. Set up the parallel experiment groups a2-G2 at the same time under identical conditions, titrate using classical dual indicator acid-base titration (phenolphthalein-methyl orange), and record the results.
The experiment adopts anhydrous sodium carbonate solid and 0.5mol/L sodium hydroxide standard solution as reference substances. And the reference substance was treated as follows.
Adding 5g of anhydrous sodium carbonate into a crucible, putting the crucible containing the anhydrous sodium carbonate solid into a muffle furnace, setting the temperature at 270 ℃, raising the temperature for 30min, preserving the temperature for 4 hours, and putting the obtained anhydrous sodium carbonate into a vacuum drier for storage for later use.
Adding 25mL of standard sodium hydroxide into a 250mL volumetric flask, using tertiary water to fix the volume to the scale mark of the volumetric flask, shaking up, and placing the prepared sodium hydroxide solution into a narrow-mouth bottle with a rubber plug for later use.
The volume of sodium hydroxide solution and the mass of sodium carbonate required for each set of experiments were calculated as shown in table 1:
TABLE 1
| A | B | C | D | E | F | G | |
| Concentration ratio of ppm | 1:5 | 2:4 | 3:3 | 4:2 | 5:1 | 6:0 | 0:6 |
| V(NaOH) | 1.176 | 2.352 | 3.58 | 4.704 | 5.880 | 7.056 | 0 |
| m(Na2CO3) | 0.0088 | 0.0071 | 0.0053 | 0.0035 | 0.0018 | 0 | 0.0106 |
Each set of samples was dissolved and mixed in seven sets of 250mL erlenmeyer flasks with 60mL of tertiary water, shaken up and labeled with the a-G set, and titrated using the following protocol:
taking a conical flask, adding 10 drops of the mixed indicator into the conical flask containing the sample washing liquid, wherein the solution is changed into semitransparent purple black, placing the conical flask on an iron stand, titrating by using a burette, shaking while titrating, preferably completely developing color of each drop of acid solution until the solution is changed into grass green after titrating and shaking, and recording the volume V1 of consumed hydrochloric acid.
And (3) taking excessive 0.05mol/L hydrochloric acid by using a pipette, adding the excessive hydrochloric acid into the burette to enable the liquid level of the acid liquid to rise to be above a zero line, and repeating the step of adjusting the acid liquid of the burette to zero by using a waste liquid beaker.
The waste beaker was removed and the sample solution was continued to be titrated. The solution was slowly titrated from turquoise to pink and the volume of acid consumed at this time was recorded as V2.
The data obtained were recorded as follows:
hydroxyl radical mass fraction A in sample solution1＝17.01c(V1-V2)/m×1000，ppm
Carbonate mass fraction A in the sample solution2＝60.02cV2/m×1000，ppm
Total residual alkali amount A in sample solution0＝A1+A2，ppm
Wherein c is the molar concentration of the prepared hydrochloric acid, mol/L;
m is the weighed sample mass, g.
In the above calculation formula, c is the molar concentration of the prepared hydrochloric acid, V1 is the volume of acid consumed at the first end of the titration reaction, V2 is the volume of acid consumed at the second end of the reaction, and m is the weighed sample mass (accurate to 0.0001 in the calculation).
The above experimental process was repeated to complete the titration of the seven groups a-G, and the data and the calculation results were recorded, and the obtained data are shown in table 2.
Table 2:
the titration procedure using the phenolphthalein-methyl orange classical method was:
taking a conical flask, adding 5 drops of phenolphthalein into the conical flask containing the sample washing liquid, changing the solution into light red, placing the conical flask on an iron stand, titrating by using a burette, shaking while dripping, preferably completely developing the color of each drop of acid liquid until the solution becomes colorless after titration and shaking, recording the volume V1 of consumed hydrochloric acid, dripping five drops of methyl orange indicator, titrating until the solution becomes orange, and recording the volume V2 of the acid consumed in the second step. The data obtained are shown in table 3:
table 3:
OH-the error statistics for concentration are shown in table 4:
table 4:
CO3 2-the error statistics for concentration are shown in table 5:
table 5:
the experiment is verified by using a residual alkali standard solution, and through data analysis, the residual alkali determination method provided by the invention can effectively simplify experiment operation, so that the data is more accurate and has higher stability, and the method has advancement compared with the traditional method.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.
Claims (10)
1. A method for determining the content of residual alkali in a solution, which is characterized by comprising the following steps:
(1) preparing a mixed indicator solution: preparing 1g/L methyl orange solution, 1g/L cresol red solution and 2g/L methylene blue solution with certain volumes respectively; mixing a methyl orange solution, a cresol red solution and a methylene blue solution in a certain volume ratio to obtain a mixed indicator;
(2) titration of the sample solution with hydrochloric acid solution: adding a certain volume of the mixed indicator into a conical flask containing a sample solution, wherein the solution is changed into semitransparent purple black, placing the conical flask on an iron stand, titrating by using an acid burette while shaking, preferably completely developing color of each drop of acid solution until the solution is changed into grass green after titration and shaking, and recording the volume V1 of consumed hydrochloric acid;
zeroing an acid burette;
continuing to slowly titrate until the sample solution changes from grass green to orange, and recording the volume of hydrochloric acid consumed at the moment as V2;
(3) calculating the residual alkali content in the sample solution:
hydroxyl radical mass fraction A in sample solution1＝17.01c(V1-V2)/m×1000，ppm
Carbonate mass fraction A in the sample solution2＝60.02cV2/m×1000，ppm
Total residual alkali amount A in sample solution0＝A1+A2，ppm
Wherein c is the molar concentration of the prepared hydrochloric acid, mol/L; m is the weighed sample mass, g.
2. The assay of claim 1, wherein the methyl orange solution is prepared as follows: dissolving 100mg of methyl orange solid in 100mL of water, heating and stirring the solution for 10min by using a constant-temperature magnetic stirrer until the methyl orange solid is completely dissolved, and placing the solution into a 100mL reagent bottle for later use.
3. The method according to claim 1, wherein the cresol red solution is prepared by the following method: dissolving 100mg of cresol red solid in 50mL of ethanol, shaking up, diluting to 100mL, mixing uniformly, and placing into a 100mL reagent bottle for later use.
4. The method according to claim 1, wherein the methylene blue solution is prepared by the following method: 100mg of methylene blue solid is dissolved in 50mL of water, and the dissolved methylene blue solid is placed into a 50mL reagent bottle for standby.
5. The assay of claim 1 wherein the indicator mixture comprises methyl orange solution, cresol red solution and methylene blue solution in a volume ratio of 5: 4: 1.
6. the assay of claim 1 wherein the mixed indicator comprises 40mL of methyl orange solution, 8mL of methylene blue solution and 32mL of cresol red solution.
7. An assay method according to claim 1, wherein the specific operation of the zeroing acid burette is: taking excessive hydrochloric acid by using a pipette, adding the excessive hydrochloric acid into a burette to enable the liquid level of the acid liquid to rise to be above a zero mark line, fixing the burette on a burette clamp of an iron stand, placing a small beaker for containing waste liquid below the burette clamp, looking up the scale line, and slowly discharging the acid liquid to enable the lowest part of the concave liquid level of the acid liquid in the burette to be level with the zero mark line of the burette; the molar concentration of the hydrochloric acid is 0.05 mol/L.
8. An assay method according to claim 5 or 6 wherein 10 drops of the mixing indicator are added to the conical flask containing the sample wash.
9. Use of the assay of claim 1 in the detection of a battery material, further comprising the step of sample processing of the battery material prior to detecting the residual alkali content in the battery material.
10. Use of the assay of claim 1 in the detection of battery material, wherein the battery material sample is processed by: 10g of a battery material sample which is just subjected to a sintering process is taken by using a medicine spoon and placed on a watch glass, and the watch glass is placed in the air for 40 minutes; taking one 100mL beaker, dissolving the battery material sample in 60mL tertiary water, and stirring for 3 minutes by using a magnetic stirrer;
and (3) taking out the magnetic stirrer, performing suction filtration on the washed and uniformly mixed sample by using a Buchner funnel and filter paper, taking a small amount of filtrate to clean the wall of the funnel, filtering again, repeating the process for three times, and pouring the filtrate into a 250mL conical flask for later use.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112345413A (en) * | 2020-09-18 | 2021-02-09 | 武汉大学 | Method for testing global distribution of infiltration water and inorganic solute under micro-spray irrigation condition |
| CN113092458A (en) * | 2021-04-08 | 2021-07-09 | 溧阳中科海钠科技有限责任公司 | Method for detecting residual alkali content on surface of cathode material of sodium ion battery |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105842388A (en) * | 2015-01-12 | 2016-08-10 | 内蒙古包钢钢联股份有限公司 | Method for measuring sodium carbonate in sintering synergist through acid-base titration |
| CN107907625A (en) * | 2017-11-03 | 2018-04-13 | 山西长征动力科技有限公司 | A kind of detection method of lithium electricity tertiary cathode material surface residual alkali content |
| CN108195779A (en) * | 2017-12-29 | 2018-06-22 | 广东省生态环境技术研究所 | A kind of method and application using dye indicator test mineral samplers surface p H |
| CN109580606A (en) * | 2018-12-12 | 2019-04-05 | 彩虹集团新能源股份有限公司 | A kind of measuring method of positive electrode remained on surface lithium carbonate, lithium hydroxide content |
-
2020
- 2020-03-06 CN CN202010150211.9A patent/CN111289686A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105842388A (en) * | 2015-01-12 | 2016-08-10 | 内蒙古包钢钢联股份有限公司 | Method for measuring sodium carbonate in sintering synergist through acid-base titration |
| CN107907625A (en) * | 2017-11-03 | 2018-04-13 | 山西长征动力科技有限公司 | A kind of detection method of lithium electricity tertiary cathode material surface residual alkali content |
| CN108195779A (en) * | 2017-12-29 | 2018-06-22 | 广东省生态环境技术研究所 | A kind of method and application using dye indicator test mineral samplers surface p H |
| CN109580606A (en) * | 2018-12-12 | 2019-04-05 | 彩虹集团新能源股份有限公司 | A kind of measuring method of positive electrode remained on surface lithium carbonate, lithium hydroxide content |
Non-Patent Citations (2)
| Title |
|---|
| 《基础化学实验 无机化学和分析化学分册》: "《基础化学实验 无机化学和分析化学分册》", 31 July 2017, 中国中医药出版社 * |
| 张开诚 等: "《普通高等教育"十三五"规划教材 化学实验教程》", 28 February 2018 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112345413A (en) * | 2020-09-18 | 2021-02-09 | 武汉大学 | Method for testing global distribution of infiltration water and inorganic solute under micro-spray irrigation condition |
| CN112345413B (en) * | 2020-09-18 | 2021-12-17 | 武汉大学 | Method for testing global distribution of infiltration water and inorganic solute under micro-spray irrigation condition |
| CN113092458A (en) * | 2021-04-08 | 2021-07-09 | 溧阳中科海钠科技有限责任公司 | Method for detecting residual alkali content on surface of cathode material of sodium ion battery |
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