GB/T 21994.3-2008Chemical analysis of magnesium fluoride - Part 3: Determination of fluoride content - Distillation-thorium nitrate titration volumetric method (English PDF)
氟化镁化学分析方法 第3部分：氟含量的测定 蒸馏－硝酸钍容量法
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Issued by
SAMR; SAC
Level / Type
National · Recommended
Issue date
June 9, 2008
Implementation date
December 1, 2008
Scope
GB/T 21994.3-2008 is the English-translated version of 氟化镁化学分析方法 第3部分：氟含量的测定 蒸馏－硝酸钍容量法.
GB/T 21994.3-2008 is the Chinese standard "Chemical analysis of magnesium fluoride - Part 3: Determination of fluoride content - Distillation-thorium nitrate titration volumetric method".
Its scope clause reads: This section provides the determination of fluorine in the amount of magnesium fluoride. This section applies to the determination of magnesium fluoride of fluorine content. Measurement range. 40% to 62%. Its clauses include method summary; reagents.
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Document preview — GB/T 21994.3-2008
National Standard of the People's Republic of China
- ICS
- 77.040.30
- Classification
- H 12
Issued by: State Administration for Market Regulation; Standardization Administration of the PRC
Contents
- 1 Scope
- 2 Normative references
- 3 Method summary
- 4 Reagents
1 Scope
This section provides the determination of fluorine in the amount of magnesium fluoride.
This section applies to the determination of magnesium fluoride of fluorine content. Measurement range. 40% to 62%.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this part. For dated references, subsequent
Amendments (not including errata content) or revisions do not apply to this section, however, encourage the parties to this part of the research agreement
Whether the latest versions of these documents. For undated references, the latest edition to adapt to this section.
GB/T 21994.1-2008 Chemical analysis of magnesium fluoride - Part 1. Sample Preparation and Storage
3 Method summary
Sample with sodium carbonate melt. By sulfuric acid - steam distillation after the separation of fluorine, with sodium alizarin yellow - Methylene blue as indicator, with thorium nitrate solution
Titrated.
4 Reagents
4.1
anhydrous sodium carbonate.
4.2
sulfate (1 + 1).
4.3
Alizarin Red S indicator (2.5g/L).
4.4
Sodium hydroxide solution (20g/L).
4.5
hydrochloric acid solution (99 + 1).
4.6
acetic acid (1mol/L).
4.7
Methylene blue indicator (0.1g/L).
4.8 thorium nitrate standard solution
4.8.1 preparation
Weigh 1.8g thorium nitrate tetrahydrate [Th (NO3) 4 · 4H2O], dissolved in water and diluted to 1L, mixing quiet place, the next day
Calibration.
4.8.2 Calibration
Weigh 0.1300g ignition advance and placed in a desiccator to cool anhydrous sodium fluoride (high purity) at 600 °C. With 20mL ~
30mL water distillation flask transferred fluoride. Press the following analysis steps 7.4.2 ~ 7.4.3 conduct. Meanwhile blank experiment.
The actual concentration of thorium nitrate standard solution according to the formula (1).
Ba m1 = 0.4525 × 2 × Vp Vp 1-
103 (1)
Where.
Ba --- the actual concentration of thorium nitrate standard solution, in milligrams per milliliter (mg/mL);
M1 --- said to take quality sodium fluoride, in grams (g);
Volume consumed Vp 1 --- Calibration thorium nitrate standard solution, in milliliters (mL);
2 --- consumed Vp thorium nitrate standard blank test solution volume in milliliters (mL of);
0.4525 --- sodium fluoride in terms of coefficients.
GB/T 20975.28-2019 | GB/T 20975.29-2019 | GB/T 20975.30-2019 | GB/T 21994.5-2008 | GB/T 21994.4-2008 | GB/T 21994.2-2008 | […]
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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.
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Related Standards
GB/T 21994.4-2008 — Chemical analysis of magnesium fluoride - Part 4: Determination of magnesium - EDTA volumetric method
GB/T 21994.2-2008 — Chemical analysis of magnesium fluoride - Part 2: Determination of moisture content - Gravimetric method
GB/T 21994.5-2008 — Chemical analysis of magnesium fluoride - Part 5: Determiantion of calcium content - Method of flame atomic absorption spectrometry
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