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GB/T 6150.1-2008 English PDF (GBT6150.1-2008)

GB/T 6150.1-2008 English PDF (GBT6150.1-2008)

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GB/T 6150.1-2008: Methods for chemical analysis of tungsten concentrates -- Determination of tungsten trioxide content -- The ammonium tungstate igniting gravimetric method

This part specifies the method for determination of tungsten trioxide content in tungsten concentrates. This part applies to the determination of tungsten trioxide content in tungsten concentrates. Measuring range: ????50%. 2 Method summary spectrophotometry The sample is dissolved in hydrochloric acid, nitric acid, and perchloric acid in the presence of a small amount of ammonium fluoride, and concentrated until white smoke is emitted to drive out fluoride ions and nitrate radicals. Tungsten is precipitated in the form of tungsten acid and filtered to separate it from most coexisting elements. The tungstic acid is dissolved in ammonia water, the filtrate is evaporated to dryness, burnt, de-siliconized with hydrofluoric acid, and burnt again; after that, the amount of tungsten trioxide is weighed. The content of tungsten trioxide in the residue is determined by spectrophotometry and the result is corrected. 3 Reagents Unless otherwise stated, the reagents used in this part are analytically pure reagents that comply with national standards or industry standards, and the water used is distilled water. 3.1 Sodium peroxide. 3.2 Ammonium fluoride. 3.3 Disodium ethylenediaminetetraace
GB/T 6150.1-2008
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 77.120.99
H 63
Replacing GB/T 6150.1-1985
Methods for chemical analysis of tungsten concentrates -
Determination of tungsten trioxide content - The ammonium
tungstate igniting gravimetric method
ISSUED ON: MARCH 31, 2008
IMPLEMENTED ON: SEPTEMBER 1, 2008
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Method summary spectrophotometry ... 6
3 Reagents ... 6
4 Samples ... 7
5 Analysis steps ... 7
6 Calculation of analysis results ... 9
7 Precision ... 9
8 Quality assurance and control ... 10
Foreword
GB/T 6150 Methods for chemical analysis of tungsten concentrates is divided into 17 parts:
GB/T 6150.1 Methods for chemical analysis of tungsten concentrates - Determination of tungsten trioxide content - The ammonium tungstate igniting gravimetric method GB/T 6150.2 Methods for chemical analysis of tungsten concentrates - Part 2: Determination of tin content - Potassium iodate titrimetry and inductively coupled plasma atomic emission spectrometry
GB/T 6150.3 Methods for chemical analysis of tungsten concentrates - Determination of phosphorus content - The phosphorus molybdenum yellow spectrophotometry GB/T 6150.4 Methods for chemical analysis of tungsten concentrates - Part 4: Determination of sulfur content - High frequency-infrared absorption method and combustion-iodometric method
GB/T 6150.5 Methods for chemical analysis of tungsten concentrates - Determination of calcium content - EDTA volumetric method and flame atomic absorption spectrometric method
GB/T 6150.6 Methods for chemical analysis of tungsten concentrates - Part 6: Determination of moisture content - Gravimetric method
GB/T 6150.7 Methods for chemical analysis of tungsten concentrates - Determination of tantalum content and niobium content - Inductively coupled plasma emission spectrometry and spectrophotometry
GB/T 6150.8 Methods for chemical analysis of tungsten concentrates - Part 8: Determination of molybdenum content - Thiocyanate spectrophotometry method GB/T 6150.9 Methods for chemical analysis of tungsten concentrates - Determination of copper content - Flame atomic absorption spectrometry
GB/T 6150.10 Methods for chemical analysis of tungsten concentrates - Part 10: Determination of lead content - Hydride generation atomic fluorescence spectrometry and flame atomic absorption spectrometry
GB/T 6150.11 Methods for chemical analysis of tungsten concentrates - Determination of zinc content - Flame atomic absorption spectrometric method
Methods for chemical analysis of tungsten concentrates -
Determination of tungsten trioxide content - The ammonium
tungstate igniting gravimetric method
1 Scope
This part specifies the method for determination of tungsten trioxide content in tungsten concentrates.
This part applies to the determination of tungsten trioxide content in tungsten concentrates. Measuring range: ???50%.
2 Method summary spectrophotometry
The sample is dissolved in hydrochloric acid, nitric acid, and perchloric acid in the presence of a small amount of ammonium fluoride, and concentrated until white smoke is emitted to drive out fluoride ions and nitrate radicals. Tungsten is precipitated in the form of tungsten acid and filtered to separate it from most coexisting elements. The tungstic acid is dissolved in ammonia water, the filtrate is evaporated to dryness, burnt, de-siliconized with hydrofluoric acid, and burnt again; after that, the amount of tungsten trioxide is weighed. The content of tungsten trioxide in the residue is determined by spectrophotometry and the result is corrected.
3 Reagents
Unless otherwise stated, the reagents used in this part are analytically pure reagents that comply with national standards or industry standards, and the water used is distilled water.
3.1 Sodium peroxide.
3.2 Ammonium fluoride.
3.3 Disodium ethylenediaminetetraacetate (EDTA).
3.4 Hydrochloric acid (??=1.19 g/mL).
3.5 Nitric acid (??=1.42 g/mL).
3.6 Hydrofluoric acid (??=1.15 g/mL).
3.7 Absolute ethanol.
3.8 Ammonia solution (1+4).
3.9 Sodium hydroxide solution (48 g/L).
3.10 Perchloric acid (??=1.67 g/mL).
3.11 Perchloric acid cleaning solution (1+199).
3.12 Potassium thiocyanate solution (350 g/L).
3.13 Titanium trichloride-hydrochloric acid mixture: Pipette 0.5 mL of titanium trichloride solution (150 g/L), dilute to 100 mL with hydrochloric acid (2+3), and mix well. Prepare freshly just before use.
3.14 Tungsten trioxide standard solution: Weigh 0.1000 g of dried pure tungsten trioxide (more than 99.95%), place it in a 250 mL beaker, add 48 g of sodium hydroxide and about 100 mL of water, and heat slightly until dissolved completely; cool and transfer it to a 1000 mL volumetric flask, dilute to volume with water, mix well, and store it in a plastic bottle. 1 mL of this solution contains 0.100 mg of tungsten trioxide. 4 Samples
4.1 The particle size of the sample is less than 0.074 mm.
4.2 The sample is pre-dried at 105 ??C~110 ??C for 2 hours and then placed in a desiccator to cool to room temperature.
5 Analysis steps
5.1 Test portion
Weigh 0.5 g of the sample (accurate to 0.0001 g).
5.2 Number of determinations
Carry out two determinations independently and take the average value.
5.3 Determination
5.3.1 Place the test portion (5.1) into a 250 mL beaker, add 5 0mL of hydrochloric acid (3.4), and place the beaker in a boiling water bath to dissolve for 30 min~40 min; add 0.3 g of ammonium fluoride (3.2), shake, and continue dissolving for 10 minutes. Take the beaker out, place it on an electric stove to concentrate the volume to 30 mL~40 mL, add 3 mL of perchloric acid (3.10) and 2 mL of nitric acid (3.5), and continue to heat at low temperature until white smoke comes out for 1 minute; take the beaker down, cool it slightly, and blow wash the watch glass and cup wall with water, dilute to 30 mL~40 mL; boil the solution, remove the beaker, and let it stand for a while. 5.3.2 Filter the solution with the medium-speed quantitative filter paper into a 100 mL volumetric flask. Use the pouring method to wash the beaker and the filter paper each 4 times with perchloric acid washing solution (3.11) and each once with water. 5.3.3 Remove the volumetric flask, add 0.5 mL of absolute ethanol (3.7), and dilute with water to about 80 mL (after the tungstic acid is dissolved into the platinum dish and washed, pour the solution into the original beaker for leaching residue). 5.3.4 Place the weighed platinum dish under the funnel, blow wash the beaker and filter paper with the hot ammonia solution (3.8) to dissolve the tungstic acid, and transfer the residue in the beaker into the funnel and clean the beaker with a wiping stick. 5.3.5 Place the platinum dish in a boiling water bath to evaporate the solution to dryness, move the dish to an electric furnace to heat to drive out the ammonium salt, then move it to a high-temperature furnace of 780 ???~800 ???, and burn it for 10 min~15 min; take it out and cool it. Add 5 mL of hydrofluoric acid (3.6), place it in a boiling water bath and evaporate the solution to dryness, then move it to a high-temperature furnace of 780 ??C~800 ??C, and burn it for 10 minutes; take it out, cool it to room temperature in a desiccator, weigh it, and burn it repeatedly, until the weight is constant. 5.3.6 Determination of the content of tungsten trioxide in the residue: 5.3.6.1 Transfer the residue obtained in 5.3.4 together with the filter paper into a 30 mL iron crucible, place it on an electric stove to dry and ash, add about 6 g of sodium peroxide (3.1) after cooling, and melt the content in a high-temperature furnace of 700 ???~750 ??? until it is cherry red and transparent; take the content out, cool it slightly, and place it in the washing filtrate obtained in 5.3.3 [If it is scheelite concentrate, add 1 g of EDTA (3.3)]; after the leaching is complete, wash the crucible with water, cool the washing filtrate, and transfer it to a 100 mL volumetric flask; dilute it with water to the mark, mix well, and let it stand for clarification. Pipette 2.00 mL~10.00 mL of the supernatant [if it is less than 10.00 mL, make up with sodium hydroxide solution (3.9)] into a 50 mL colorimetric tube.
5.3.6.2 Add 2 mL of potassium thiocyanate solution (3.12), dilute it to the mark with titanium trichloride-hydrochloric acid mixture (3.13), mix well, and leave it for 10 minutes; then, transfer part of the solution into a 1 cm cuvette, use the reagent blank as a reference, measure the absorbance at the wavelength of 400 nm on the
spectrophotometer, and find out the corresponding content of tungsten trioxide from the working curve.

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