Method for detecting dispersibility of carbon black in lead plaster

Abstract

The invention provides a method for detecting dispersibility of carbon black in lead paste. The method comprises the following steps: S1, sampling; s2, crushing; s3, dissolving; s4, keeping constant weight of qualitative filter paper; s5, suction filtration; s6, drying; s7, burning the crucible until the weight is constant; s8, burning the test sample until the weight is constant; s9, calculating the content of the carbon element in the lead paste; and S10, calculating the dispersibility of the carbon element. The method for detecting the dispersibility of the carbon black in the lead plaster is simple to operate and ingenious in conception, can accurately detect the dispersibility of the carbon black in the lead plaster, not only can solve the problem that the dispersibility of the carbon black in the lead plaster cannot be detected, but also can be used for determining lead plaster production process conditions and determining lead plaster mixing time, speed and other production conditions according to the dispersibility of the carbon black. And investigation when the battery performance is abnormal is also facilitated, whether the manufacturing and production process conditions affect the battery performance abnormity or not is confirmed according to the dispersibility of the carbon black, and the problem of poor charging acceptance of the battery is solved from the source.

Description

Technical Field

[0001] The present invention relates to a detection method, and more particularly to a method for detecting the dispersion of carbon black in lead paste. Background Art

[0002] When a lead-acid battery discharges, the active material on the electrode plate is converted into lead sulfate, which is a non-conductive substance. Excessive lead sulfate on the electrode plate will reduce the conductivity of the electrode plate, thereby affecting the charge acceptance of the battery. To enhance the charge acceptance of the battery, the addition of carbon black can compensate for this defect of low conductivity and make the battery charging easier.

[0003] The production of the electrode plate mainly involves the processes of lead paste mixing, grid coating, and electrode plate curing and aging. As an additive to the negative electrode lead paste, carbon black is added to the lead powder during the mixing process. Currently, there is no relevant detection technology for how to detect the uniformity of the dispersion of carbon black in the lead paste. Therefore, a method is needed to analyze the dispersion of carbon black in the lead paste. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention proposes a method for detecting the dispersion of carbon black in lead paste, which can accurately detect the dispersion of carbon black in lead paste. Thus, according to the dispersion of carbon black, it can be confirmed whether there are abnormalities in the production process conditions of lead paste mixing and timely adjustments can be made.

[0005] To achieve the above technical solution, the present invention provides a method for detecting the dispersion of carbon black in lead paste, specifically including the following steps:

[0006] S1. After the negative electrode lead paste is completely mixed, accurately sample 50.0 g of the lead paste sample and dry it in a constant temperature environment of 105 ± 2 °C for 5 hours;

[0007] S2. Use a mortar and pestle to crush the dried lead paste sample into a powder;

[0008] S3. After the lead paste sample passes through a 120-mesh sieve, weigh about 10.0 g of the sample, denoted as m 0 , place it in a 500 ml beaker, add 30 ml of nitric acid with a mass concentration of 25%, heat and dissolve it in a water bath at 70 - 80 °C for 1.5 hours, then add 30 ml of ammonium acetate solution with a mass concentration of 50% to the beaker after the water bath, and then heat and dissolve it in a water bath at 70 - 80 °C for 1.5 hours;

[0009] S4. Take a special qualitative filter paper and dry it in an electrothermal constant temperature forced air drying oven for 1 hour. After drying, transfer the qualitative filter paper to a desiccator to cool. After cooling to room temperature, weigh it, and repeat the operation until constant weight, denoted as m 1 ;

[0010] S5. Use a dried, cooled, and weighed filter paper to perform suction filtration on the lead paste sample solution that has been heated and dissolved. Then, rinse the residues on the beaker and glass rod with 25% nitric acid and perform suction filtration until the filtrate contains no lead ions. After suction filtration is completed, air-dry the filter paper and then dry it in an electrothermal constant-temperature forced-air drying oven for 1 hour.

[0011] S6. After drying is completed, transfer the filter paper to a desiccator for cooling. After cooling to room temperature, weigh it. Repeat the operation until a constant weight is achieved, and record it as m. 2 ;

[0012] S7. Place a porcelain crucible in a box-type resistance furnace, adjust the temperature to 850 - 900 °C, and perform high-temperature calcination for 2 hours. After calcination is completed, take out the porcelain crucible and cool it for 5 minutes, then transfer it to a desiccator for cooling. After cooling to room temperature, weigh it. Repeat the operation until a constant weight is achieved, and record it as m. 3 ;

[0013] S8. Spread the filter paper from step S6 in the porcelain crucible that has been weighed to a constant weight. Slightly open the lid to allow the filter paper to be fully calcined, then transfer it to a box-type resistance furnace, adjust the temperature to 850 - 900 °C, and perform high-temperature calcination for 2 hours. After calcination is completed, completely cover the lid of the porcelain crucible, take it out and cool it for 5 minutes, then transfer it to a desiccator for cooling. After cooling to room temperature, weigh it. Repeat the operation until a constant weight is achieved, and record it as m. 4 ;

[0014] S9. Calculate the carbon element content in the lead paste according to formula 1:

[0015]

[0016] Where: m 0 --- The mass of the powdered lead paste sample, in grams;

[0017] m 1 --- The mass of the qualitative filter paper after drying before suction filtration, in grams;

[0018] m 2 --- The mass of the qualitative filter paper after suction filtration and drying, in grams;

[0019] m 3 --- The mass of the porcelain crucible after being weighed to a constant weight, in grams;

[0020] m 4 --- The mass of the porcelain crucible and the qualitative filter paper after calcination, in grams;

[0021] S10. Calculate the carbon element dispersibility according to formula 2:

[0022] Dispersibility = ω(carbon element)max - ω(carbon element)min Formula 2.

[0023] Preferably, in step S1, after the negative paste is finished mixing, take 4 samples of about 50 g at the four corners of the mixer respectively, place them in a sealed bag and make marks and numbers: ①, ②, ③, ④, so as to realize the sampling for 4 experiments at one time.

[0024] Preferably, in step S5, the test method for the filtrate without lead ions is as follows: take 1 mL of the filtrate, add 2 drops of sulfuric acid solution with a mass concentration of 20%, and the filtrate remains transparent after standing for 5 min.

[0025] Preferably, when weighing in steps S1 - S8, it is accurate to 0.1 mg.

[0026] Preferably, the porcelain crucible for ignition to constant weight in steps S7 and S8 includes a porcelain crucible body and a lid.

[0027] The beneficial effect of the method for detecting the dispersibility of carbon black in the paste provided by the present invention is as follows: The method for detecting the dispersibility of carbon black in the paste is simple in operation and ingenious in conception, and can accurately detect the dispersibility of carbon black in the paste. It can not only solve the problem that the dispersibility of carbon black in the paste cannot be detected, but also be used to determine the production process conditions of the paste. According to the dispersibility of carbon black, determine the mixing time, rate and other production conditions of the paste. It is also helpful for the investigation when the battery performance is abnormal. According to the dispersibility of carbon black, confirm whether the manufacturing production process conditions have an impact on the abnormal battery performance, and solve the problem of poor charging acceptance of the battery from the source. Specific embodiments

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment: A method for detecting the dispersibility of carbon black in a paste.

[0030] A method for detecting the dispersibility of carbon black in a paste, the specific analysis method and steps are as follows:

[0031] (1) After the negative paste is finished mixing, accurately sample 50.0 g of the paste sample.

[0032] (2) Dry in a constant temperature environment of 105 ± 2 °C for 5 hours.

[0033] (3) Use a mortar and pestle to crush the dried paste sample into a powder.

[0034] (4) After the paste sample passes through a 120 - mesh sieve, weigh about 10.0 g of the sample and record it as m0 , place it in a 500 ml beaker, add 30 ml of nitric acid with a mass concentration of 25%, heat and dissolve it in a water bath at 70 - 80 °C for 1.5 hours, then add 30 ml of ammonium acetate solution with a mass concentration of 50% to the beaker after the water bath, and heat and dissolve it in a water bath at 70 - 80 °C for another 1.5 hours.

[0035] (5) Take a special qualitative filter paper and put it into an electrothermal constant temperature forced air drying oven to dry for 1 hour. After drying, transfer the qualitative filter paper to a desiccator to cool. After cooling to room temperature, weigh it, and repeat the operation until a constant weight is achieved (accurate to 0.1 mg, denoted as m 1 ).

[0036] (6) Use the dried, cooled, and weighed filter paper to perform suction filtration on the lead paste sample solution that has completed heating and dissolution, and rinse and filter the residues on the beaker and glass rod with nitric acid with a mass concentration of 25% until the filtrate does not contain lead ions (test method: take 1 mL of the filtrate, add 2 drops of sulfuric acid solution with a mass concentration of 20%, and the filtrate remains transparent after standing for 5 min). After suction filtration, air-dry the filter paper, and then use the electrothermal constant temperature forced air drying oven to dry for 1 hour again. After drying, transfer the paper to a desiccator to cool. After cooling to room temperature, weigh it and repeat the operation until a constant weight is achieved (accurate to 0.1 mg, denoted as m 2 ).

[0037] (7) Take a porcelain crucible (including the lid) and put it into a box-type resistance furnace, adjust the temperature to 850 - 900 °C, and perform high-temperature calcination for 2 hours. After calcination, take out the porcelain crucible (including the lid) and cool it for 5 minutes, then transfer it to a desiccator to cool. After cooling to room temperature, weigh it, and repeat the operation until a constant weight is achieved (accurate to 0.1 mg, denoted as m 3 ).

[0038] (8) Spread the filter paper from step 5 and put it into the porcelain crucible that has achieved a constant weight (slightly open the lid for the filter paper to be fully calcined), then transfer it into the box-type resistance furnace, adjust the temperature to 850 - 900 °C, and perform high-temperature calcination for 2 hours. After calcination, completely cover the lid of the porcelain crucible, take it out and cool it for 5 minutes, and then transfer it to a desiccator to cool. After cooling to room temperature, weigh it, and repeat the operation until a constant weight is achieved (accurate to 0.1 mg, denoted as m 4 ).

[0039] (9) Operate on 4 samples according to the operation methods in steps 3, 4, 5, 6, 7, and 8, and calculate the carbon element content in the lead paste according to formula 1:

[0040]

[0041] Among them: m 0 --- mass of the powdered lead paste sample, unit: gram;

[0042] m 1 --- The quality of the qualitative filter paper after drying before suction filtration, in grams;

[0043] m 2 --- The quality of the qualitative filter paper after suction filtration and drying, in grams;

[0044] m 3 --- The quality of the porcelain crucible after constant weight, in grams;

[0045] m 4 --- The quality of the porcelain crucible and the qualitative filter paper after burning, in grams;

[0046] (10) Calculate the carbon element dispersity according to Formula 2:

[0047] Dispersity = ω(carbon element)max - ω(carbon element)min Formula 2.

[0048] The analysis method of the present invention will be further described below with reference to examples.

[0049] (a) After the negative electrode lead paste is finished mixing, take 4 samples of 50 g each from the four corners of the mixer, place them in a sealed bag and make good marks and numbers: upper left ①, upper right ②, lower left ③, lower right ④.

[0050] (b) Put the 4 samples into an electrothermal constant temperature blast drying oven and dry them for 5 hours in a constant temperature environment of 105 ± 2 °C.

[0051] (c) Grind the 4 dried samples into powders using a mortar and pestle, pass them through a 120-mesh sieve, and then put them into 4 washed and dried weighing bottles respectively.

[0052] (d) Take samples in sequence and perform the operation methods in steps (3), (4), (5), (6), (7), (8), and (9) of the analysis method on the 4 samples. The carbon element contents in the lead paste samples at each position are shown in Table 1:

[0053] Table 1 Carbon element contents measured for different samples

[0054] Sample number ① ② ③ ④ <![CDATA[m 0 (g)]]> 10.0065 10.0081 10.0050 10.0046 <![CDATA[m 1 (g)]]> 2.005 2.0083 2.0005 2.0068 <![CDATA[m 2 (g)]]> 2.6003 2.6050 2.6541 2.6654 <![CDATA[m 3 (g)]]> 60.0050 60.0050 60.0050 60.0050 <![CDATA[m 4 (g)]]> 60.4580 60.4521 60.5885 60.4860 <![CDATA[ω (碳元素) > 1.42％ 1.49％ 0.70％ 1.75％

[0055] Calculate the dispersity of the carbon element. The dispersity of the carbon element in the negative electrode lead paste = ω(carbon element)max - ω(carbon element)min, that is, = 1.75% - 0.70% = 0.95%. The smaller the dispersity value, the better the dispersion uniformity of the carbon black in the lead paste.

[0056] The detection method for the dispersion of carbon black in the lead paste is simple in operation and ingenious in conception, capable of accurately detecting the dispersion of carbon black in the lead paste. It can not only solve the problem of the inability to detect the dispersion of carbon black in the lead paste, but also be used to determine the production process conditions of the lead paste. According to the dispersion of carbon black, production conditions such as the mixing time and rate of the lead paste can be determined. It is also helpful for the investigation when the battery performance is abnormal. According to the dispersion of carbon black, it can be confirmed whether the manufacturing production process conditions have an impact on the abnormal battery performance, and the problem of poor charge acceptance of the battery can be solved from the source.

[0057] The above are the preferred embodiments of the present invention, but the present invention should not be limited to the content disclosed in this embodiment. Therefore, all equivalent or modified implementations completed without departing from the spirit disclosed by the present invention fall within the protection scope of the present invention.

Claims

1. A method for detecting the dispersion of carbon black in lead paste, characterized in that The specific steps include: S1. After the negative electrode lead paste is mixed, accurately sample 50.0g of lead paste sample and dry it in a constant temperature environment of 105±2℃ for 5 hours; S2. Use a mortar and pestle to crush the dried lead paste sample into powder; S3. After the lead paste sample passes through a 120-mesh sieve, weigh about 10.0 g of the sample, recorded as m0, and place it in a 500 ml beaker. Add 30 ml of 25% nitric acid, heat and dissolve it in a water bath at 70-80°C for 1.5 hours, then add 30 ml of 50% acetyl ammonium solution to the beaker after the water bath, and heat and dissolve it in a water bath at 70-80°C for 1.5 hours. S4, take the special qualitative filter paper and put it into the electric constant temperature blast drying oven for drying for 1 hour. After the drying is completed, transfer the qualitative filter paper to the dryer to cool. After cooling to room temperature, weigh it, repeat the operation until constant weight, recorded as m1; S5. Use the dried, cooled and weighed filter paper to filter the heated and dissolved lead paste sample solution, and rinse and filter the residual substances on the beaker and glass rod with 25% nitric acid until the filtrate does not contain lead ions. After the filtration is completed, dry the filter paper and then use an electric constant temperature blast drying oven to dry it for 1 hour; S6. After the drying is completed, the filter paper is transferred to a dryer to cool, and after cooling to room temperature, it is weighed. After the drying is completed, the filter paper is transferred to a dryer to cool, and after cooling to room temperature, it is weighed. Repeat the operation until a constant weight is obtained, which is recorded as m2; S7, take the porcelain crucible and put it into a box-type resistance furnace, adjust the temperature to 850-900°C, and calcine at high temperature for 2 hours. After the calcination is completed, take out the porcelain crucible and cool it for 5 minutes, then transfer it to a dryer to cool it. After cooling to room temperature, weigh it, repeat the operation until constant weight, recorded as m3; S8, spread the filter paper in step S6 into a porcelain crucible that has been subjected to constant weight, open the lid slightly to allow the filter paper to be fully burned, and then move it into a box-type resistance furnace, adjust the temperature to 850-900°C, and burn it at high temperature for 2 hours. After the burning is completed, completely cover the porcelain crucible with the lid, take it out and cool it for 5 minutes, then transfer it to a dryer to cool it, cool it to room temperature, weigh it, and repeat the operation until constant weight is obtained, which is recorded as m4; S9. Calculate the carbon content in the lead paste according to formula 1: Where: m0---mass of powdered lead paste sample, in grams; m1---Qualitative filter paper mass after drying before filtration, in grams; m2---Qualitative filter paper mass after filtration and drying, in grams; m3---The mass of the porcelain crucible after constant weight, in grams; m4---The mass of the porcelain crucible and qualitative filter paper after burning, in grams; S10. Calculate the carbon element dispersion according to formula 2: Dispersibility = ω(carbon element)max-ω(carbon element)min Formula 2.

2. The method for detecting the dispersion of carbon black in lead paste according to claim 1, characterized in that: In the step S1, after the negative electrode lead paste is mixed, four samples of about 50g are taken from the four corners of the paste mixing machine, respectively, placed in sealed bags and marked and numbered: ①, ②, ③, ④.

3. The method for detecting the dispersion of carbon black in lead paste according to claim 1, characterized in that: In step S5, the test method for whether the filtrate does not contain lead ions is: take 1 mL of the filtrate, add 2 drops of 20% sulfuric acid solution, and let it stand for 5 minutes until the filtrate remains transparent.

4. The method for detecting the dispersion of carbon black in lead paste according to claim 1, characterized in that: The weighing in steps S1-S8 is accurate to 0.1 mg.

5. The method for detecting the dispersion of carbon black in lead paste according to claim 1, characterized in that: The porcelain crucible for constant weight burning in step S7 and step S8 comprises a porcelain crucible body and a cover.

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