HG/T 4823-2023Manganese sulfate for batteries (English PDF)

7.1 General provisions

The reagents and water used in this document, unless otherwise specified, refer to analytical reagents and grade 3 water specified in Table 1 of GB/T 6682-2008.

The standard titration solutions, impurity standard solutions, preparations and products used in the test, unless otherwise specified, are prepared in accordance with the provisions of HG/T 3696.1, HG/T 3696.2, HG/T 3696.3.

7.2 Appearance inspection

Under natural light, place the solid product on a white-backed watch glass or white porcelain plate; place the solution product in a beaker; judge the appearance by visual inspection.

7.3 Determination of manganese sulfate content

7.3.1 Principle

In an ammonia-ammonium chloride buffer solution with a pH of about 10, use chrome black T as an indicator and use disodium ethylenediaminetetraacetic acid (EDTA) standard titration solution to titrate, until the solution changes from purple-red to pure blue, which is the end point. Calculate the manganese sulfate content based on the consumption of the standard titration solution.

7.3.2 Reagents or materials

7.3.3 Test steps

7.3.4 Test data processing

7.4.1 Principle

The specimen is dissolved in nitric acid; the intensity of the characteristic spectrum of the elements to be measured (iron, zinc, copper, lead, cadmium, chromium, potassium, sodium, calcium, magnesium, nickel, cobalt, aluminum) is determined by inductively coupled plasma emission spectrometer; the working curve method is used for quantification.

7.4.2 Reagents or materials

7.4.2.1 Nitric acid solution. 1+1

Prepared with high-grade pure reagents.

7.4.3 Instruments and equipment

Inductively coupled plasma emission spectrometer.

7.4.4 Test steps

7.4.5 Test data processing

7.5.1 Reagents or materials

7.5.2 Instruments and equipment

Atomic absorption spectrophotometer. Equipped with a lead hollow cathode lamp.

7.5.3 Test steps

7.5.4 Test data processing

7.5.4.1 Data processing of solid specimen

The lead content is calculated as the mass fraction of lead w4 according to formula (6).

7.6 Determination of chloride content

7.6.1 Spectrophotometry (arbitration method)

7.6.2 Ion chromatography

7.6.2.1 Principle

The specimen is dissolved in water, separated by anion exchange column using an ion chromatograph, detected by suppressed conductivity method, quantified by external standard method (peak area/peak height). The mass concentration of chlorine is found from the working curve and its content is calculated.

7.6.2.2 Reagents or materials

7.6.2.3 Instruments and equipment

7.6.2.4 Test steps

7.6.2.5 Test data processing

7.7 Determination of water-insoluble matter content

7.7.1 Reagents or materials

7.7.2 Instruments and equipment

7.7.3 Test steps

Weigh about 20 g (accurate to 0.01 g) of the specimen. Place it in a 250 mL beaker.

Dissolve it in 200 mL hot water without carbon dioxide. Filter it with a glass crucible that has been dried at 105 °C ± 2 °C to a constant mass. Wash it with hot water until there is no sulfate (check with barium chloride solution). Place it in an electric constant temperature drying oven, to dry it at 105 °C ± 2 °C to a constant mass.

7.7.4 Test data processing

The water-insoluble content is expressed as mass fraction w7 and is calculated according to formula (12).

7.8 pH determination

7.8.1 Instruments and equipment

Acidity meter. The graduation value is 0.1 pH unit; it is equipped with pH electrode and calomel electrode.

7.8.2 Test steps

Solid product. Determine according to the method specified in 5.8 of HG/T 2962-2010.

Solution product. Take 50 mL of liquid specimen. Place it in a dry beaker. Determine the pH with an acidity meter.

7.9 Determination of fineness

7.9.1 Instruments and equipment

Test sieve. phi200×50-0.4/0.25 GB/T 6003.1-2022, equipped with sieve cover and sieve bottom.

7.9.2 Test steps

Weigh about 50 g of specimen. Place it in the test sieve. Install the sieve cover and sieve bottom. Perform manual sieving. If there is no residue on the sieve, it means that all the samples have passed.

7.10 Determination of silicon content

7.10.1 Principle

The specimen is treated with sulfuric acid. The silicic acid and ammonium molybdate generate silicomolybdic heteropoly acid. Hydrofluoric acid is added to dissolve silicon and eliminate the influence of some impurities. Ammonium ferrous sulfate is used to reduce and generate silicon-molybdenum blue. The absorbance is measured at a wavelength of 810 nm on a spectrophotometer.

7.10.2 Reagents or materials

7.10.3 Instruments and equipment

7.10.4 Test steps

7.10.4.1 Drawing of working curve

Pipette 0.00 mL, 1.00 mL, 2.00 mL, 4.00 mL, 8.00 mL, 12.00 mL of silicon standard solution respectively. Place in six 100 mL volumetric flasks. Add 9 mL of sulfuric acid solution respectively. Use water to dilute it to about 40 mL. Place in a 50 °C ± 2 °C constant temperature water bath. After 5 minutes, add 10 mL of ammonium molybdate solution while shaking. Use a small amount of water, to rinse the ammonium molybdate solution attached to the inner wall of the bottle. Keep warm in a 50 °C ± 2 °C constant temperature water bath for 5 minutes. Shake from time to time. Remove and cool to room temperature with running water. Add 15 mL of hydrofluoric acid solution. Mix well. Add 5 mL of ammonium ferrous sulfate solution within 30 seconds. Mix well. Use water to dilute to the mark. Let stand for 15 minutes.

Transfer to a set of cuvettes. Use the blank solution as a reference, to measure its absorbance at a wavelength of 810 nm. Draw a working curve with the mass concentration of silicon (mg/L) as the abscissa and the absorbance as the ordinate.

7.10.4.2 Preparation of test solution

7.11 Determination of fluoride content

7.11.1 Fluoride ion selective electrode method (arbitration method)

7.11.1.1 Principle

In the presence of a total ionic strength regulator, the fluoride ion content is determined using an ion selective electrode as the indicator electrode and a saturated calomel electrode as the reference electrode.

7.11.1.2 Reagents or materials

7.11.1.3 Instruments and equipment

7.11.1.4 Test steps

7.11.1.5 Test data processing

7.11.2 Ion chromatography

7.12 Determination of magnetic foreign matter content

7.12.1 Principle

The magnetic material in the specimen is adsorbed by a magnetic rod and dissolved with aqua regia. The working curve method is used, to determine the nickel, iron, zinc chromium contents with an inductively coupled plasma emission spectrometer; the magnetic foreign matter content is obtained by calculation.

7.12.2 Reagents or materials

7.12.3 Instruments and equipment

7.13 Determination of oil content

7.13.1 Reagents or materials

Warning. Perchloroethylene has irritating and anesthetic effects. When using it, it shall strictly follow the safety technical instructions.

7.13.2 Instruments and equipment

Infrared spectrophotometer for oil measurement.

7.13.3 Test steps