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GB/T 21994.6-2008: Chemical analysis of magnesium fluoride -- Part 6: Determination of silica content -- Molybdenum blue photometric method
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| GB/T 21994.6-2008 | English | 139 |
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Chemical analysis of magnesium fluoride -- Part 6: Determination of silica content -- Molybdenum blue photometric method
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GB/T 21994.6-2008
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Basic data | Standard ID | GB/T 21994.6-2008 (GB/T21994.6-2008) | | Description (Translated English) | Chemical analysis of magnesium fluoride -- Part 6: Determination of silica content -- Molybdenum blue photometric method | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | H12 | | Classification of International Standard | 77.040.30 | | Word Count Estimation | 6,672 | | Date of Issue | 2008-06-09 | | Date of Implementation | 2008-12-01 | | Quoted Standard | GB/T 21994.1-2008 | | Regulation (derived from) | National Standard Approval Announcement 2008 No.9 (Total No.122) | | Issuing agency(ies) | General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China | | Summary | This standard specifies the determination of magnesium fluoride in silica. This section applies to the determination of magnesium fluoride in silica. Measuring range: �� 1. 00%. | GB/T 21994.6-2008: Chemical analysis of magnesium fluoride -- Part 6: Determination of silica content -- Molybdenum blue photometric method
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Chemical analysis of magnesium fluoride Part 6. Determination of silica content Molybdenum blue photometric method.
ICS 77.040.30
H12
National Standards of People's Republic of China
Chemical analysis of magnesium fluoride
Part 6. Determination of silica content
Molybdenum blue spectrophotometric method
Posted 2008-06-09
2008-12-01 implementation
Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
Standardization Administration of China released
Foreword
GB/T 21994 "Chemical analysis of magnesium fluoride" is divided into eight sections.
--- Part 1. Preparation and storage of test samples;
--- Part 2. Determination of the weight of water in the wet method;
--- Part 3. Determination of distillation of fluorine content - thorium nitrate volumetric method;
--- Part 4. Determination of magnesium content - EDTA volumetric method;
--- Part 5. Determination of calcium content by flame atomic absorption spectrometry;
--- Part 6. Determination of silicon dioxide content - Molybdenum blue spectrophotometric method;
--- Part 7. Determination of iron oxide content phenanthroline spectrophotometry;
--- Part 8. Determination of sulfate content of barium sulfate gravimetric method.
Part is divided into 6 sections.
This part is proposed by the China Nonferrous Metals Industry Association.
The non-ferrous metal part by the National Standardization Technical Committee.
This section is Hunan Nonferrous fluorine chemical limited liability company, China Nonferrous Metals Industry Institute of Standards Metrology and Quality is responsible for drafting.
This section is drafted. Hunan Nonferrous fluorine chemical limited liability company.
Participated in the drafting of this section. Fluoride Chemicals Co., Ltd., Silver fluoride limited liability company.
The main drafters of this section. Li Zhijian, Liao Zhihui, Chen Xiang Yu, Zhu Liang, Xu Jin Xue, Wang Jianping, Guo Xianhui, Bo, Li Ye.
Chemical analysis of magnesium fluoride
Part 6. Determination of silica content
Molybdenum blue spectrophotometric method
1 Scope
This section provides the determination of magnesium fluoride silica.
This section applies to the determination of magnesium fluoride in silica. Measuring range. ≤1.00%.
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 and boric acid flux melt, hydrochloric acid. Points to take the test solution between pH0.85 ~ pH0.90, silicon and molybdic acid
Salt formation yellow silicon molybdenum heteropoly acid. In the high acidity sulfuric acid medium, the reducing agent is a Silicon molybdenum blue, in the spectrophotometer at a wavelength of 620nm
Measuring the absorbance.
4 Reagents
4.1 anhydrous sodium carbonate.
4.2 boric acid.
4.3 hydrochloride (3mol/L).
4.4 ammonium molybdate solution (100g/L).
4.5 sulfate (1 + 1).
4.6 ascorbic acid solution (25g/L). When using the preparation.
4.7 silica standard stock solution. Weigh 0.5000g finely pre-burning 1h at 1000 ℃, and cooled to room in the dryer
Temperature silica (99.9%), placed in a platinum crucible, to which was added 5g of anhydrous sodium carbonate in the (4.1), mix well with a platinum spoon, set high
Oven temperature at 950 ℃ carefully melted (about 10min), then cool, water was added to the crucible, heated slowly to dissolve completely. The solution was cooled
CAUTION moved 1000mL volumetric flask, dilute to volume, and mix. Immediately poured into a polyethylene bottle. This solution 1mL containing 0.500mg two
Silicon oxide.
4.8 silica standard solution. Pipette 50.00mL silica standard stock solution (4.7) in 500mL flask, diluted with water
To the mark, and mix. Immediately transferred to plastic bottles. This solution 1mL containing 0.0500mg silica. The solution was formulated before use now.
5 instruments and equipment
5.1 platinum dish. flat, diameter 70mm, height 35mm, with platinum cover.
5.2 EAF. to control the temperature at 550 ℃ ± 25 ℃.
5.3 Furnace temperature. the temperature can be controlled at 850 ℃ ± 25 ℃.
5.4 pH meter. with a glass electrode.
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