ASTM E1917-97

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1917 – 97
Standard Test Method for
Determination of Phosphorus in Nickel, Ferronickel, and
Nickel Alloys by Phosphovanadomolybdate Molecular
Absorption Spectrometric Method
This standard is issued under the fixed designation E 1917; 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 ISO 11400:1992(E) Nickel, Ferronickel and Nickel
Alloys—Determination of Phosphorus Content—
1.1 This test method covers the determination of phospho-
Phosphovanadomolybdate Molecular Absorption Spectro-
rus in nickel, ferronickel, and nickel alloys in the 0.0007 %
metric Method
through 0.05 % range.
1.2 Arsenic, chromium, hafnium, niobium, silicon, tanta-
3. Summary of Test Method
lum, titanium, and tungsten interfere, but the interference can
3.1 The sample is dissolved in a mixture of hydrochloric
be avoided by complexation or volatilization (for Cr). The
acid and nitric acid. The solution is evaporated to perchloric
lowest phosphorus content (0.0007 %) can be reached only in
acid fumes and chromium is removed as volatile chromyl
samples with low contents of interfering elements.
chloride. Silicon and refractory elements are complexed with
1.3 This standard does not purport to address all of the
fluoride ions. The phosphorus is converted to phosphovanado-
safety concerns, if any, associated with its use. It is the
molybdic acid in a perchloric and nitric acid solution. The
responsibility of the user of this standard to establish appro-
phosphovanadomolybdic acid is extracted with 2-methyl-2-
priate safety and health practices and determine the applica-
pentanone in the presence of citric acid to complex arsenic.
bility of regulatory limitations prior to use. For specific hazards
Absorbance is measured at 355 nm.
associated with the use of this practice see Practices E 50.
Refer to specific warning notes given throughout this test
4. Significance and Use
method.
4.1 This test method is used for the analysis of nickel,
2. Referenced Documents ferronickel, and nickel base alloy samples by molecular ab-
sorption spectrometry to check compliance with compositional
2.1 ASTM Standards:
specifications. It is assumed that all who use the procedure will
E 50 Practices for Apparatus, Reagents, and Safety Precau-
2 be trained analysts capable of performing common laboratory
tions for Chemical Analysis of Metals
procedures skillfully and safely. It is expected that the work
E 882 Guide for Accountability and Quality Control in the
3 will be performed in a properly equipped laboratory and that
Chemical Analysis Laboratory
proper waste disposal procedures will be followed. Appropriate
E 1452 Practice for Preparation of Calibration Solutions for
quality control practices must be followed, such as those
Spectrophotometric and for Spectroscopic Atomic Analy-
3 described in Guide E 882.
sis
E 1601 Practice for Conducting Interlaboratory Study to
5. Apparatus
Evaluate the Performance of an Analytical Method
5.1 Spectrophotometer—Capable of measuring absorbance
2.2 ISO Standards:
at a wavelength of 355 nm.
ISO 5725:1986 Precision of Test Methods—Determination
5.2 Cells—To fit spectrophotometer, having an optical path
of Repeatability and Reproducibility for a Standard Test
4 of 1 cm.
Method by Inter-laboratory Tests
NOTE 1—Cells having other dimensions can be used, provided suitable
adjustments can be made in the amount of sample and reagents used.
This practice is under the jurisdiction of ASTM Committee E-1 on Analytical
Chemistry of Metals, Ores and Related Materials and is the direct responsibility of
6. Reagents
Subcommittee E01.08 on Nickel, Cobalt and High Temperature Alloys.
6.1 Purity and Concentration of Reagents—The purity and
Current edition approved November 10, 1997. Published June 1998.
Annual Book of ASTM Standards, Vol 03.05. concentration of common chemical reagents shall conform to
Annual Book of ASTM Standards, Vol 03.06.
Practices E 50. The reagents should be free of or contain only
Available from American National Standards Institute, 11 West 42nd Street,
New York, NY 10036.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E1917–97
minimal amounts (<0.1 μg/g) of phosphorus. Calibration solu- 9. Procedure
tions shall be prepared in accordance with Practice E 1452.
9.1 Test Portion and Preparation of Test Solution:
6.1.1 Verify the absence of phosphorus in the reagents using
9.1.1 Weigh to the nearest 0.1 mg a test portion of the
the blank test (9.6.1). Reagents giving high blank values are
sample in accordance with Table 1.
unsuitable and should not be used. The blank value for all
9.1.2 Transfer the test portion to a polytetrafluoroethylene
reagents should be below 0.0005 % P calculated fora1g
(PTFE) beaker and add 5 mL of HNO and then 5 mL of HCl.
sample.
For samples with high contents of Nb, Si, Ta, or Hf, also add
6.2 Ammonium Metavanadate Solution—Dissolve 2.5 g of
7 mL of HF. Cover the beaker with a PTFE cover and heat
ammonium metavanadate (NH VO ) in water and dilute to 1 L.
4 3 gently until the reaction ceases. Use a sandbath or other means
6.3 Citric Acid Solution—Dissolve 500 g citric acid mono-
to avoid direct contact of the PTFE beaker with a metal
hydrate (C H O ·H O) in water and dilute to 1 L.
6 8 7 2
hotplate surface. Add 10 mL of HClO and, leaving a small
6.4 Fluoroboric Acid Solution—Disperse 75 g of boric acid
opening to release the vapors, evaporate to dense HClO
(H BO ) in 600 mL of hot water in a plastic beaker. Add 50 mL
3 3
fumes.
HF (40 %) and dilute to 1 L. Digest over medium heat until the
NOTE 3—Nickel and some copper bearing nickel alloys, such as monel,
boric acid is dissolved. Store in plastic bottle. The solution
will dissolve more readily in HNO (1+1).
should be gently heated if the boric acid forms crystals.
NOTE 4—Warning: Fuming HClO is a powerful oxidant and can
cause explosions when in contact with organic materials. All evaporations
NOTE 2—Warning: HF and fluoroboric acid are extremely irritating
must be carried out in the presence of HNO and in a fume hood suitable
and corrosive to skin and mucous membranes, producing severe skin
for use with HClO .
burns that are slow to heal. In case of contact with skin, wash well with
water and seek medical advice. When using HF and fluoroboric acid,
9.1.3 For samples containing less than 0.1 % chromium,
always wear appropriate safety gear, such as goggles and gloves.
omit the next step and proceed directly to 9.3.
6.5 Hexaammonium Heptamolybdate Solution—Dissolve
9.2 Removal of Chromium:
15 g of hexaammonium heptamolybdate tetrahydrate
9.2.1 Continue fuming for 3 min. Cautiously begin adding
[(NH ) Mo O ·4H O] in warm water and dilute to 100 mL.
HCl drop by drop to the fuming solution in the partly covered
4 6 7 24 2
Prepare fresh solution each day. If high and unstable blank
beaker until colored fumes are no longer liberated. Then
values appear, there might be a problem with the salt used. In
resume fuming to re-oxidize the remaining chromium. Repeat
such a case, switch to another lot.
the treatment until no brown fumes appear when the HCl is
6.6 4-methyl-2-pentanone—methylisobutyl ketone.
added. Cool to room temperature.
6.7 Phosphorus Stock Calibration Solution (1.000 g/L)—
9.3 Complexation:
Transfer 4.3942 g of potassium dihydrogenorthophosphate
9.3.1 Add 25 mL HNO (1+4) and 4 mL HF to the solution
(KH PO ) (which has been previously dried at 110°C to
2 4 and heat for 8 to 10 minutes until the precipitate is dissolved.
constant weight and cooled in a desiccator) toa1L volumetric
NOTE 5—It is important that the precipitated refractory oxides dissolve
flask. Dissolve in water, dilute to the mark and mix.
completely. If this does not happen, add another 2 mL HF and repeat the
6.8 Phosphorus Calibration Solution (10 mg/L)—Transfer
boiling. If the precipitate still remains undissolved, a new test sample of
10.0 mL of the phosphorus stock calibration solution toa1L
a smaller weight must be taken for the analysis.
volumetric flask. Dilute t
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