YS/T 575.3-2007 English PDF (YST575.3-2007)

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YS/T 575.3-2007: Methods for chemical analysis of bauxite. Part 3: Determination of silicon dioxide content. Molybdenum blue photometric method
YS/T 575.3-2007
NON-FERROUS METAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.10
Q 52
Replacing YS/T 575.3-2006
Methods for Chemical Analysis of Bauxite -
Part 3: Determination of Silicon Dioxide Content -
Molybdenum Blue Photometric Method
ISSUED ON: NOVEMBER 14, 2007
IMPLEMENTED ON: MAY 01, 2008
Issued by: National Development and Reform Commission
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Method Principle ... 6
3 Reagents ... 6
4 Apparatus ... 7
5 Specimen ... 7
6 Analysis Procedures ... 7
7 Calculation of Analysis Results ... 8
8 Precision ... 9
9 Quality Assurance and Control ... 9
Foreword
YS/T 575-2007 Methods for Chemical Analysis of Bauxite is a modification to YS/T
575-2006 (formerly GB/T 3257-1999). It has 24 parts in total:
--- Part 1: Determination of aluminum oxide content - EDTA titrimetric method;
--- Part 2: Determination of silicon dioxide content - Gravimetric-molybdenum blue
photometric method;
--- Part 3: Determination of silicon dioxide content - Molybdenum blue photometric
method;
--- Part 4: Determination of iron oxide content - Potassium titrimetric method;
--- Part 5: Determination of iron oxide content - Orthophenanthroline photometric
method;
--- Part 6: Determination of titanium dioxide content - Diantipyrylmethane
photometric method;
--- Part 7: Determination of calcium oxide content - Flame atomic absorption
spectrophotometric method;
--- Part 8: Determination of magnesium oxide content - Flame atomic absorption
spectrophotometric method;
--- Part 9: Determination of potassium oxide, sodium oxide content - Flame atomic
absorption spectrophotometric method;
--- Part 10: Determination of manganese oxide content - Flame atomic absorption
spectrophotometric method;
--- Part 11: Determination of chromium oxide content - Flame atomic absorption
spectrophotometric method;
--- Part 12: Determination of vanadium pentoxide content - N-benzoyl-N-
phenylhydroxylamine photometric method;
--- Part 13: Determination of zinc content - Flame atomic absorption
spectrophotometric method;
--- Part 14: Determination the total content of rare earth oxide Tribromo-arsenazo
photometric method;
--- Part 15: Determination of gallium oxide content - Rhodamine B-extraction
Methods for Chemical Analysis of Bauxite -
Part 3: Determination of Silicon Dioxide Content -
Molybdenum Blue Photometric Method
1 Scope
This Part specifies the determination of silicon dioxide content in bauxite.
This Part is applicable to the determination of silicon dioxide content in bauxite; the
measurement range: ≤15.00%.
2 Method Principle
The specimen was melted with alkali, leached with hydrochloric acid; add ammonium
molybdate to form silicon molybdenum heteropoly acid; and then reduced to
molybdenum blue by ferrous iron. Use a spectrophotometer to measure the
absorbance at a wavelength of 700 nm.
3 Reagents
3.1 Sodium hydroxide.
3.2 Hydrochloric acid (1+1).
3.3 Hydrochloric acid (1+99).
3.4 Hydrochloric acid (1+3).
3.5 Ammonium molybdate solution (100g/L). Filter it, if necessary; if there are more
precipitates, then re-prepare the solution.
3.6 Sulfuric acid-oxalic acid-ferrous ammonium sulfate mixed solution: take 30g of
ferrous ammonium sulfate in a 1L beaker; add 150mL of water; and slowly add 165mL
of sulfuric acid (1+1) and stir to dissolve. After cooling, transfer it to a 1L volumetric
flask; take 30g of oxalic acid in another beaker; use the hot water to dissolve; transfer
it to the above volumetric flask after cooling; dilute to the scale with water; and mix
evenly (the storage period of this solution is 10 days).
After water and molten material are reacted and completely leached, pour the solution
into the shaking volumetric flask; wash the crucible with a small amount of hot water;
then wash the crucible with a small amount of hydrochloric acid (3.2); and then wash
the crucible and funnel with hot water; shake well, cool to room temperature; dilute to
the scale with water, mix well. Transfer 5.00 mL of test solution to a 100 mL volumetric
flask; add 40 mL of hydrochloric acid (3.3); and shake well.
6.4.3 Add 4mL of ammonium molybdate solution (3.5) and shake well to develop color
(for 20min at temperature < 20°C; for 15min at temperature 20°C ~ 29°C; and for 10min
at temperature 30°C ~ 40°C). Add 20mL of sulfuric acid-oxalic acid-ferrous ammonium
sulfate mixed solution (3.6) and shake well. Dilute with water to the scale and mix
evenly. Stand for 10min. Take a part of the test solution in a 1cm cuvette; measure the
absorbance with the blank test solution as a reference at a wavelength of 700 nm; and
check the corresponding amount of silicon dioxide from the working curve.
6.5 Drawing of working curve
Separately take 0.00mL, 0.50mL, 1.00mL, 2.00mL, 3.00mL, 4.00mL, 5.00mL, 6.00mL,
7.00mL, 8.00mL of silicon dioxide (3.7) into 100mL volumetric flasks. Supplement each
flask with 2.5mL of hydrochloric acid (3.4); and then add water to a volume of 50mL.
Operate by following the analysis procedure 6.4.3. Take the reagent blank as the
reference; measure its absorbance. Draw working curve by taking the amount of silicon
dioxide as the abscissa, and absorbance as the ordinate.
7 Calculation of Analysis Results
Calculate the mass fraction (%) of silicon dioxide as per the following Formula:
Where:
m1 – the amount of silicon dioxide checked from the working curve, in g;
V1 – volume of test solution that is separately taken, in mL;
V – total volume of test solution, in mL;
m – mass of specimen, in g.