YB/T 4019-2020 English PDF (YB/T4019-2020)

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YB/T 4019-2020: Determination of chemical activity of light calcined magnesia
YB/T 4019-2020
YB
FERROUS METALLURGY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 73.080
D 52
Replacing YB/T 4019-2006
Determination of chemical activity of light calcined
magnesia
ISSUED ON: DECEMBER 09, 2020
IMPLEMENTED ON: APRIL 01, 2021
Issued by: Ministry of Industry and Information Technology of the People's
Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Reagents ... 4
4 Instruments ... 6
5 Sampling and sample preparation ... 7
6 Determination methods ... 7
7 Test report ... 9
Determination of chemical activity of light calcined
magnesia
1 Scope
This Standard specifies the determination method for the chemical activity of light
calcined magnesia and the scope of the method for determining the content of active
magnesia, instruments, reagents, sampling and sample preparation, determination
method and test report.
This Standard applies to the determination of the chemical activity of light calcined
magnesia with a particle size smaller than 0.045 mm or smaller than 0.125 mm.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 8170, Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 12573, Sampling method for cement
GB/T 12805, Laboratory glassware - Burettes
GB/T 12806, Laboratory glassware - One-mark volumetric flasks
GB/T 12808, Laboratory glassware - One mark pipettes
3 Reagents
Unless otherwise stated in the analysis, use analytically-pure reagents and distilled
water or equivalent-pure water.
3.1 Citric acid.
3.2 Sodium hydroxide.
3.3 Potassium hydrogen phthalate: reference reagent.
3.4 Phenolphthalein indicator: 10 g/L ethanol solution.
3.5 Sodium hydroxide standard solution (0.2 mol/L).
3.5.1 Preparation: Weigh 8 g of sodium hydroxide (3.2) and dissolve in 100 mL of water.
Cool to room temperature. Transfer into a 1000 mL volumetric flask. Dilute to the scale.
Mix well. Transfer to a plastic bottle for later use (calibrate it when it is needed).
3.5.2 Calibration: Accurately weigh 3 portions of 0.8168 g of potassium hydrogen
phthalate (3.3) that have been dried at 105°C~110°C for 2 h and cooled to room
temperature. Respectively place them in 400 mL beakers. Add 200 mL of boil cooling
water. Stir to make them dissolved. Then add 3 drops of phenolphthalein indicator (3.4).
Use sodium hydroxide standard solution (3.5.1) to titrate to reddish, which shall be the
end.
The concentration of sodium hydroxide standard solution is measured by the amount of
substance concentration CNaOH. The value is expressed in mol/L. Calculate according
to formula (1):
Where,
m - The numerical value of the mass of the weighed potassium hydrogen phthalate, in
grams (g);
V - The numerical value of the volume of the consumed sodium hydroxide standard
solution (3.5.1) to titrate potassium hydrogen phthalate, in milliliters (mL);
204.2 - The numerical value of the molar mass of potassium hydrogen phthalate, in
grams per mole (g/mol).
Take the average value as the calculation result. Round to four significant figures.
3.6 Citric acid standard solution (0.07 mol/L)
3.6.1 Preparation: Weigh 14.71 g of citric acid, to the nearest of 0.0001 g. Place in a
400 mL of beaker. Add 200 mL of water to dissolve. Transfer to a 1000 mL volumetric
flask. Use water to dilute to the scale. Mix well. Store in a refrigerator. It shall be valid
for 1 month.
3.6.2 Calibration: Weigh 3 portions of 50.00 mL of citric acid solution. Respectively
place them in 400 mL beakers. Add 200 mL of distilled water. Add 3 drops of
phenolphthalein indicator (3.4). Use sodium hydroxide standard solution (3.5.1) to
titrate to reddish, which shall be the end.
The concentration of the citric acid standard solution is calculated by the substance
4.12 Glass weighing bottle: Φ35 mm × 70 mm.
5 Sampling and sample preparation
5.1 Collect laboratory samples according to GB/T 12573.
5.2 Sample preparation
5.2.1 Crush lumpy laboratory samples to less than 6.7 mm. Use a sample divider or
quartering method to divide to about 100 g.
5.2.2 Crush the divided sample to less than 0.5 mm. Then reduce to about 20 g. Process
into specimens with a particle size as small as 0.045 mm or 0.125 mm.
5.2.3 The powdery laboratory sample is directly reduced to about 100 g. Pass through
a 0.045 mm sieve (320 mesh) or a 0.125 mm sieve (120 mesh). Then reduce to about
20 g.
5.2.4 The specimen shall be dried at 105°C~110°C for 2 h before analysis. Then cool
to room temperature in a desiccator.
6 Determination methods
6.1 Determination of chemical activity of light calcined magnesia by citric acid
neutralization method
6.1.1 Method summary
A certain amount of light calcined magnesia reacts with citric acid solution. Measure
the activity of light calcined magnesia according to the length of reaction. A short
reaction time indicates good activity while a long reaction time indicates poor activity.
6.1.2 Determination steps
6.1.2.1 Specimen size
Weigh about 1.700 g of specimen, to the nearest of 0.0003 g.
6.1.2.2 Determination quantity
During the determination, two specimens shall be weighed for parallel determination.
6.1.2.3 Determination
Place the specimen (6.1.2.1) in a dry 300 mL beaker. Put in a stir bar. Place on a
magnetic stirrer with constant temperature of 40°C. Immediately and quickly add 200.0