Standard Test Methods for Chemical Analysis of Silicon and Ferrosilicon

SCOPE
DESIG: E360 96 (Reapproved 2001) ^TITLE: Standard Test Methods for Chemical Analysis of Silicon and Ferrosilicon ^SCOPE:
1.1 These test methods cover the chemical analysis of silicon and ferrosilicon having chemical compositions within the following limits:ElementConcentration, %Aluminum2.0 maxArsenic0.10 maxCalcium1.00 maxCarbon0.50 maxChromium0.50 maxCopper0.30 maxManganese1.00 maxNickel0.30 maxPhosphorus0.10 maxSilicon20.00 to 99.5Sulfur0.025 maxTitanium0.20 max
1.2 The test methods appear in the following order: SectionsArsenic by the Molybdenum Blue Photometric MethodAluminum by the Quinolinate Photometric and GravimetricMethodsSilicon by the Sodium Peroxide Fusion-Perchloric Acid Dehydration Method
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 5 and 26.8.1, 27.4.1.1, and 36.3.1.

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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 360 – 96
Standard Test Methods for
Chemical Analysis of Silicon and Ferrosilicon
This standard is issued under the fixed designation E 360; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 50 Practices for Apparatus, Reagents, and Safety Precau-
tions for Chemical Analysis of Metals
1.1 These test methods cover the chemical analysis of
E 60 Practice for Photometric and Spectrophotometric
silicon and ferrosilicon having chemical compositions within
Methods for Chemical Analysis of Metals
the following limits:
E 173 Practice for Conducting Interlaboratory Studies of
Element Concentration, %
Methods for Chemical Analysis of Metals
Aluminum 2.0 max
E 362 Test Methods for Chemical Analysis of Silicomanga-
Arsenic 0.10 max
nese and Ferrosilicon Manganese
Calcium 1.00 max
E 363 Methods for Chemical Analysis of Chromium and
Carbon 0.50 max
Chromium 0.50 max
Ferrochromium
Copper 0.30 max
E 364 Test Methods for Chemical Analysis of Ferrochrome-
Manganese 1.00 max
Silicon
Nickel 0.30 max
Phosphorus 0.10 max
Silicon 20.00 to 99.5
3. Significance and Use
Sulfur 0.025 max
3.1 These test methods for the chemical analysis of metals
Titanium 0.20 max
and alloys are primarily intended to test such materials for
1.2 The test methods appear in the following order:
compliance with compositional specifications. It is assumed
Sections
that all who use these test methods will be trained analysts
capable of performing common laboratory procedures skill-
Arsenic by the Molybdenum Blue Photometric Method 9-19
Aluminum by the Quinolinate Photometric and Gravimetric
fully and safely. It is expected that work will be performed in
Methods 20-30
a properly equipped laboratory.
Silicon by the Sodium Peroxide Fusion-Perchloric Acid
Dehydration Method 31-38
4. Apparatus, Reagents, and Photometric Practice
1.3 This standard does not purport to address all of the
4.1 Apparatus and reagents required for each determination
safety concerns, if any, associated with its use. It is the
are listed in separate sections preceding the procedure. The
responsibility of the user of this standard to establish appro-
apparatus, standard solutions, and certain other reagents used
priate safety and health practices and determine the applica-
in more than one procedure are referred to by number and shall
bility of regulatory limitations prior to use. Specific precau-
conform to the requirements prescribed in Practices E 50,
tionary statements are given in Section 5 and Note 3, Note 4,
except the photometers shall conform to the requirements
Note 7, and Note 12.
prescribed in Practice E 60.
4.2 Photometric practice prescribed in these test methods
2. Referenced Documents
shall conform to Practice E 60.
2.1 ASTM Standards:
A 100 Specification for Ferrosilicon
5. Safety Precautions
E 29 Practice for Using Significant Digits in Test Data to
5.1 For precautions to be observed in the use of certain
Determine Conformance with Specifications
reagents in these test methods, refer to Practices E 50.
E 32 Practices for Sampling Ferroalloys and Steel Additives
for Determination of Chemical Composition
6. Sampling
6.1 For procedures for sampling the material, and for
particle size of the sample for chemical analysis, refer to
These methods are under the jurisdiction of ASTM Committee E-1 on
Practices E 32.
Analytical Chemistry for Metals, Ores, and Related Materials and are the direct
responsibility of Subcommittee E01.01 on Iron, Steel, and Ferroalloys.
7. Rounding Off Calculated Values
Current edition approved April 10, 1996. Published June 1996. Originally
e1
published as E 360 – 70 T. Last previous edition E 360 – 85 (1991) .
7.1 Calculated values shall be rounded off to the desired
Annual Book of ASTM Standards, Vol 01.02.
Annual Book of ASTM Standards, Vol 14.02.
4 5
Annual Book of ASTM Standards, Vol 03.05. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 360
number of places as directed in 3.4 to 3.6 of Practice E 29. 14. Apparatus
14.1 Distillation Apparatus, Fig. 1.
8. Interlaboratory Studies
14.2 Zirconium Crucibles, 30-mL capacity.
8.1 These test methods have been evaluated in accordance
15. Reagents
with Practice E 173, unless otherwise noted in the Precision
and Bias section. 15.1 Ammonium Bromide (NH Br).
15.2 Ammonium Molybdate Solution (10 g/L)—Dissolve
ARSENIC BY THE MOLYBDENUM BLUE
2.5 g of ammonium heptamolybdate tetrahydrate ((NH )
4 6-
PHOTOMETRIC METHOD
Mo O ·4H O) in 40 mL of warm water. Add 128 mL of
7 24 2
H SO (1+3), dilute to 250 mL, and mix.
9. Scope
15.3 Ammonium Molybdate-Hydrazine Sulfate Solution—
9.1 This method covers the determination of arsenic in
Dilute 100 mL of ammonium molybdate solution to 900 mL,
silicon and ferrosilicon in concentrations from 0.001 to 0.10 %.
add 10 mL of hydrazine sulfate solution, dilute to 1 L, and mix.
Do not use a solution that has stood more than 1 h.
10. Summary of Method
15.4 Arsenic, Standard Solution A (1 mL = 0.10 mg As)—
10.1 Arsenic is first separated by distillation as the trivalent
Transfer 0.1320 g of arsenic trioxide (As O)toa1-L
2 3
chloride. Ammonium molybdate is added to form arsenomo-
volumetric flask, dissolve in 100 mL of HCl, cool, dilute to
lybdate which is then reduced by hydrazine sulfate to form the
volume, and mix.
molybdenum blue complex. Photometric measurement is made
15.5 Arsenic, Standard Solution B (1 mL = 0.01 mg As)—
at approximately 850 nm.
Using a pipet, transfer 100 mL of arsenic Solution A (1
mL = 0.10 mg As) to a 1-L volumetric flask, dilute to volume,
11. Concentration Range
and mix.
11.1 The recommended concentration range is 0.01 to 0.15
15.6 Hydrazine Sulfate ((NH ) ·H SO ).
2 2 2 4
mg of arsenic per 50 mL of solution using a 1-cm cell.
15.7 Hydrazine Sulfate Solution (1.5 g/L)—Dissolve 1.5 g
NOTE 1—This method has been written for cells having a 1-cm light of hydrazine sulfate ((NH ) ·H SO ) in water, dilute to 1 L,
2 2 2 4
path. Cells having other dimensions may be used, provided suitable
and mix. Do not use a solution that has stood more than 1 day.
adjustments can be made in the amount of sample and reagents used.
15.8 Sodium Carbonate (Na CO ).
2 3
15.9 Sodium Peroxide (Na O ).
2 2
12. Stability of Color
16. Preparation of Calibration Curve
12.1 The color is stable for at least 2 h.
16.1 Calibration Solutions:
13. Interferences
16.1.1 Using pipets, transfer 1, 2, 5, 10, and 15 mL of
13.1 The elements ordinarily present do not interfere if their arsenic Solution B (1 mL = 0.01 mg As) to 125-mL Erlenmeyer
concentrations are under the maximum limits shown in 1.1. flasks.
FIG. 1 Arsenic Distillation Apparatus
E 360
16.1.2 Add 10 mL of HNO and evaporate the solution to inside wall of the original 800-mL beaker. Wash the precipitate
dryness on a hot plate. Bake for 30 min at 150 to 180°C. from the paper using a fine stream of water. Pass 25 mL of
Remove from the hot plate. Add 45 mL of ammonium HNO (1+1) over the paper, and wash well with water but do
molybdate-hydrazine sulfate solution to each flask, warm not exceed a total volume of 40 mL. Discard the paper. Warm
gently to dissolve the residue, and transfer the solution to a gently until the precipitate dissolves.
50-mL volumetric flask. Proceed as directed in 16.3. 17.1.5 Transfer the solution to the distillation flask, add 1 g
16.2 Reference Solution—Transfer 10 mL of HNO to a of NH Br and 0.75 g of hydrazine sulfate. Add 20 mL of HNO
3 4 3
125-mL Erlenmeyer flask and proceed as directed in 16.1.2. (1+1) to the receiving flask, and place the flask in an 800-mL
16.3 Color Development—Heat the flask in a boiling water beaker containing cold water. Assemble the apparatus (Fig. 1),
bath for 15 min. Remove the flask, cool to room temperature, heat the distillation flask, and distill into the receiving flask.
dilute to volume with ammonium molybdate-hydrazine sulfate 17.1.6 Distill until the volume is reduced to 10 mL or until
solution and mix. oxides of nitrogen are noted in the distillation flask. Remove
the distillation flask from the heat source. Place the receiving
16.4 Photometry:
16.4.1 Multiple-Cell Photometer—Measure the cell correc- flask on a hot plate and evaporate the solution to dryness. Bake
for 30 min at 150 to 180°C. Add 45 mL of ammonium
tion using absorption cells with a 1-cm light path and a light
band centered at approximately 850 nm. Using the test cell, molybdate-hydrazine sulfate solution to the flask, warm gently
to dissolve the residue, and transfer the solution to a 50-mL
take the photometric readings of the calibration solutions.
16.4.2 Single-Cell Photometer—Transfer a suitable portion volumetric flask. Proceed as directed in 17.3.
17.2 Reference Solution—Carry a reagent blank through the
of the reference solution to an absorption cell with a 1-cm light
entire procedure using the same amounts of all reagents with
path and adjust the photometer to the initial setting, using a
the sample omitted, for use as a reference solution.
light band centered at approximately 850 nm. While maintain-
17.3 Color Development—Proceed as directed in 16.3.
ing this adjustment, take the photometric readings of the
17.4 Photometry—Take the photometric reading of the test
calibration solutions.
solution as directed in 16.4.
16.5 Calibration Curve—Plot the net photometric readings
of the calibration solutions against milligrams of arsenic per 50
18. Calculation
mL of solution.
18.1 Convert the net photometric reading of the test solution
to milligrams of arsenic by means of the calibration curve.
17. Procedure
Calculate the percentage of arsenic as follows:
17.1 Test Solution:
Arsenic, % 5 A/~B 3 10! (1)
17.1.1 Select and weigh a sample to the nearest 0.2 mg in
accordance with the following:
where:
Arsenic, % Sample Weight, g
A = milligrams of arsenic found in 50 mL of final test
solution, and
0.001 to 0.015 0.500
0.01 to 0.04 0.250 B = grams of sample represented in 50 mL of final test
0.035 to 0.10 0.125
solution.
Transfer the sample to a 30-mL zirconium crucible contain-
19. Precision and Bias
ing 10gofNa O and1gofNa CO if ferrosilicon, or8gof
2 2 2 3
19.1 Although samples covered by this method were not
Na O plus2gofNa CO if silicon metal.
2 2 2 3
available for testing, the precision data obtained for other types
17.1.2 Mix thoroughly with a metal spatula. Fuse carefully
of alloys, using the methods indicated in Table 1, should apply.
over a free flame by holding the crucible with a pair of tongs
The user is cautioned to verify by the use of reference
and slowly revolving it around the outer edge of the flame until
materials, if available, that the precision and bias of this
the contents have melted down quietly; raise the temperature
method is adequate for the contemplated use.
gradually to avoid spattering. When the contents are molten,
give the crucible a rotary motion to stir up any unattacked
ALUMINUM BY THE QUINOLINATE
particles of the alloy adhering to the bottom or sides. Finally,
PHOTOMETRIC AND GRAVIMETRIC
increase the temperature until the crucible is bright red for 1
METHODS
min. Cool the crucible to room temperature. Transfer the
crucible to an 800-mL beaker containing 60 mL of H SO 20. Scope
2 4
(1+1) and 200 mL of water. Dissolve the melt; remove and
20.1 This method covers the determination of aluminum in
rinse the crucible.
concentrations from 0.01 to 2.0 %.
17.1.3 If manganese dioxide is present, add H SO drop-
2 3
wise until the solution clears. TABLE 1 Statistical Information—Arsenic
17.1.4 Heat to boiling, and cool. While stirring vigorously,
Repeatability Reproducibility
Ferroalloy Type Arsenic Found, %
(R , E 173) (R , E 173)
add NH OH until the solution is alkaline to litmus, and then 1 2
add 3 to 5 mL in excess. Heat to boiling, remove from the heat, 1. No. 1, E 363 0.0015 0.0001 0.0005
2. No. 1, E 364 0.0018 0.0003 0.0003
and allow the precipitate to settle. Filter on a coarse filter paper
3. No. 1, E 362 0.025 0.001 0.002
and wash five times with hot water. Discard the filtrate.
4. No. 2, E 362 0.039 0.001 0.002
Remove the filter paper, carefully open it, and place it on the
E 360
21. Summary of Method 26.8 Sodium Cyanide Solution (100 g/L)—Dissolve 100 g
of sodium cyanide (NaCN) in 800 mL of water and dilute to 1
21.1 The sample is dissolved in nitric and hydrofluoric acids
L. Store in a polyethylene bottle.
and fumed with perchloric acid. After the removal of interfer-
ing elements, aluminum is separated as the quinolinate. The
NOTE 3—Caution: The preparation, storage, and use of NaCN solution
determination is completed gravimetrically when aluminum is
require care and attention. Avoid inhalation of fumes and exposure of the
skin to the chemical and its solutions. Work in a well-ventilated hood.
present in concentrations greater than 0.2 % or photometrically
Refer to Section 6 of Practices E 50. Because of the strongly alkaline
when aluminum is present in concentrations less than 0.2 %.
properties of NaCN solution, contact with glass may result in appreciable
Photometric measurement is made at approximately 395 nm.
contamination of the reagent with aluminum.
22. Concentration Range (Photometric Method)
26.9 Sodium Hydroxide Solution (200 g/L)—Dissolve 40 g
of sodium hydroxide (NaOH) in 150 mL of water in a plastic
22.1 The recommended concentration range is 0.005 to 0.10
beaker and dilute to 200 mL.
mg of aluminum per 25 mL of solution, using a 1-cm cell.
26.10 Tartaric Acid Solution (100 g/L)—Dissolve 50 g of
NOTE 2—See Note 1.
tartaric acid in 400 mL of water and dilute to 500 mL.
23. Stability of Color (Photometric Method) 27. Preparation of Calibration Curve
23.1 The color is relatively stable, but readings should be 27.1 Calibration Solutions—Using pipets, transfer 2, 5, 10,
made within 5 min. 15, and 20 mL of aluminum solution (1 mL = 0.005 mg Al) to
150 mL beakers each containing 40 mL of water and 2 mL of
24. Interferences
H SO (1+1). Proceed as directed in 27.4.
2 4
27.2 Reagent Blank—Add 40 mL of water and 2 mL of
24.1 The elements ordinarily present do not interfere if their
concentrations are under the maximum limits shown in 1.1. H SO (1+1) to a 150-mL beaker. Proceed as directed in 27.4.
27.3 Reference Solution—Chloroform (CHCl ).
25. Apparatus
27.4 Color Development:
27.4.1 Treat the solutions singly as follows: Add 1 mL of
25.1 Glassware—To prevent contamination of
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