ASTM E536-98
(Test Method)Standard Test Methods for Chemical Analysis of Zinc and Zinc Alloys
Standard Test Methods for Chemical Analysis of Zinc and Zinc Alloys
SCOPE
1.1 These test methods cover the chemical analysis of zinc and zinc alloys having chemical compositions within the following limits: Element Concentration Range, % Aluminum 0.005 to 4.5 Cadmium 0.001 to 0.5 Copper 0.001 to 1.3 Iron 0.001 to 0.1 Lead 0.001 to 1.6 Magnesium 0.001 to 0.1 Tin 0.001 to 0.1
1.2 These test methods appear as follows: Sections Aluminum by the EDTA Titrimetric Method (0.5 to 4.5 %) 8 to 15 Aluminum, Cadmium, Copper, Iron, Lead, and Magnesium by the Atomic Absorption Method 16 to 26
1.3 This standard does not purport to address all of the safety problems, 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.
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Designation: E 536 – 98
Standard Test Methods for
Chemical Analysis of Zinc and Zinc Alloys
This standard is issued under the fixed designation E 536; 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 60 Practice for Photometric and Spectrophotometric
Methods for Chemical Analysis of Metals
1.1 These test methods cover the chemical analysis of zinc
E 88 Practice for Sampling Nonferrous Metals and Alloys
and zinc alloys having chemical compositions within the
in Cast Form for Determination of Chemical Composition
following limits:
E 173 Practice for Conducting Interlaboratory Studies of
Element Concentration Range, %
Methods for Chemical Analysis of Metals
Aluminum 0.005 to 4.5
Cadmium 0.001 to 0.5
3. Significance and Use
Copper 0.001 to 1.3
3.1 These test methods for the chemical analysis of zinc
Iron 0.001 to 0.1
Lead 0.001 to 1.6
metals and alloys are primarily intended as referee methods to
Magnesium 0.001 to 0.1
test such materials for compliance with compositional specifi-
Tin 0.001 to 0.1
cations. It is assumed that all who use these test methods will
1.2 These test methods appear as follows:
be trained analysts capable of performing common laboratory
Sections
procedures skillfully and safely. It is expected that work will be
performed in a properly equipped laboratory.
Aluminum by the EDTA Titrimetric Method (0.5 to 4.5 %) 8-15
Aluminum, Cadmium, Copper, Iron, Lead, and Magnesium by the
4. Apparatus, Reagents, and Photometric Practice
Atomic Absorption Method 16-26
4.1 Apparatus and reagents required for each determination
1.3 This standard does not purport to address all of the
are listed in separate sections of each test method. The
safety concerns, if any, associated with its use. It is the
apparatus, standard solutions, and certain other reagents used
responsibility of the user of this standard to establish appro-
in more than one procedure are referred to by number and shall
priate safety and health practices and determine the applica-
conform to the requirements prescribed in Practices E 50,
bility of regulatory limitations prior to use. Specific precau-
except that photometers shall conform to the requirements
tionary statements are given in Section 5.
prescribed in Practice E 60.
2. Referenced Documents
5. Safety Precautions
2.1 ASTM Standards:
5.1 For precautions to be observed in the use of certain
E 29 Practice for Using Significant Digits in Test Data to
reagents in these test methods, refer to Practices E 50.
Determine Conformance with Specifications
E 50 Practices for Apparatus, Reagents, and Safety Precau-
6. Sampling
tions for Chemical Analysis of Metals
6.1 For procedures for sampling the material, refer to
E 55 Practice for Sampling Wrought Nonferrous Metals and
Practices E 55 and E 88.
Alloys for Determination of Chemical Composition
7. Rounding Calculated Values
7.1 Calculated values shall be rounded to the desired num-
These test methods are under the jurisdiction of ASTM Committee E-1 on
ber of places as directed in 3.4 to 3.6 of Practice E 29.
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
responsibility of Subcommittee E01.05 on Zinc, Tin, Lead, Cadmium, Beryllium,
8. Interlaboratory Studies
and Other Metals.
Current edition approved May 10, 1998. Published July 1998. Originally
8.1 These test methods have been evaluated in accordance
e1
published as E 536 – 75. Last previous edition E 536 – 84 (1993) .
with Practice E 173, unless otherwise noted in the precision
Annual Book of ASTM Standards, Vol 14.02.
Annual Book of ASTM Standards, Vol 03.05. section.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 536
ALUMINUM BY THE EDTA TITRIMETRIC METHOD 14.2 Add 100 mL of HCl (1+1). Heat until dissolution is
complete and boil for 2 to 3 min. If a residue remains, add 1
9. Scope
mL of H O and boil the solution for at least 5 min to destroy
2 2
excess H O and expel free chlorine.
9.1 This test method covers the determination of aluminum
2 2
in concentrations from 0.5 to 4.5 %.
NOTE 1—Excess peroxide and free chlorine must be removed to
prevent fading of the indicators.
10. Summary of Test Method
14.3 Transfer the solution to a 200-mL volumetric flask,
10.1 After dissolution of the sample in hydrochloric acid,
dilute to volume, and mix.
the solution is buffered and disodium (ethylenedinitrilo) tet-
14.4 Using a pipet, transfer the aliquot specified in 14.1 to a
raacetate (EDTA) is added. The excess EDTA is titrated with
500-mL wide-mouth Erlenmeyer flask.
standard zinc solution. Sodium fluoride is added to decompose
14.5 Add the volume of EDTA solution specified in 14.1
the aluminum-EDTA complex, and the released EDTA is
and dilute to 200 mL.
titrated with standard zinc solution.
NOTE 2—The amount of EDTA added must be sufficient to complex the
zinc and aluminum with some excess. The amount of EDTA required is
11. Interferences
5.7 mg for each milligram of zinc and 14.0 mg for each milligram of
11.1 The elements ordinarily present do not interfere if their
aluminum.
concentrations are under the maximum limits shown in 1.1.
14.6 Add 5 or 6 drops of methyl red solution. Add NH OH
until the color changes to orange.
12. Apparatus
14.7 Add 25 mL of sodium acetate buffer solution and boil
12.1 Magnetic Stirrer, with stirring bar covered with TFE-
for 3 to 5 min. Cool in a water bath.
fluorocarbon.
14.8 Add 4 drops of xylenol orange solution and 5 or 6
drops of bromcresol green solution.
13. Reagents
14.9 Using a TFE-fluorocarbon-covered stirring bar and a
13.1 Bromcresol Green Indicator Solution (0.4 g/L)—
magnetic stirrer, stir the solution while adding standard zinc
Dissolve 0.04 g of bromcresol green in 6 mL of 0.01 N NaOH
solution from a 50-mL buret to complex the excess EDTA. Add
solution and dilute to 100 mL.
the solution dropwise as the end point is approached. Continue
13.2 EDTA Solution (90 g/L)—Dissolve 90.0 g of disodium
the titration until the color changes from green to red. Refill the
(ethylenedinitrilo) tetraacetate dihydrate in about 800 mL of
buret.
warm water. Cool and dilute to 1 L.
14.10 Add 25 mL of NaF solution and boil for 3 to 5 min.
13.3 Methyl Red Indicator Solution (0.4 g/L)—Reagent No.
Cool in a water bath.
119.
14.11 Titrate with standard zinc solution as directed in 14.9
13.4 Sodium Acetate Buffer Solution (320 g/L)—Dissolve
and record the volume to the nearest 0.01 mL.
320 g of sodium acetate trihydrate in about 800 mL of water
and filter. Using a pH meter, adjust the pH of the solution to 5.5
15. Calculation
6 0.1 with NaOH solution or acetic acid and dilute to 1 L.
15.1 Calculate the percentage of aluminum as follows:
13.5 Sodium Fluoride Solution (Saturated)—Dissolve 60 g
Aluminum, % 5 ~AB/C! 3 100 (1)
of sodium fluoride (NaF) in 1 L of boiling water. Cool and filter
through a coarse paper. Store in a polyethylene bottle.
where:
13.6 Xylenol Orange Indicator Solution (10 g/L)—Dissolve
A 5 standard zinc solution used in 14.11, mL,
0.250 g of xylenol orange in 25 mL of water. Do not use a
B 5 aluminum equivalent of the standard zinc solution,
solution that has stood more than 1 month.
g/mL, and
13.7 Zinc Standard Solution (1 mL 5 1.00 mg Al)—
C 5 sample represented in the aliquot taken, g.
Dissolve 2.423 g of zinc metal (purity: 99.99 % min) in 20 mL
of HCl. Dilute to 100 mL. Add 3 drops of methyl red solution
16. Precision and Bias
and neutralize with NH OH. Add HCl until the color changes
16.1 Precision—Eight laboratories cooperated in testing
to red. Transfer to a 1-L volumetric flask, dilute to volume, and
this test method and obtained the results summarized in Table
mix.
1.
16.2 Bias—No information concerning the accuracy of this
14. Procedure
test method is available because certified reference materials
14.1 Select and weigh a sample to the nearest 1 mg, in
suitable for chemical test methods were not available when the
accordance with the following:
interlaboratory test was performed. The analyst is urged to use
.
Aluminum, Sample Aliquot, EDTA
% Weight, g mL Addition, mL
TABLE 1 Statistical Information
Test Aluminum Repeatability Reproducibility (R , )
0.5 to 1.5 10.0 50 165 to 168 2
Specimen Found, % (R , E 173) E 173
1.5 to 2.5 6.0 50 103 to 106 1
G-3 0.3998 0.0190 0.0254
2.5 to 4.5 5.0 40 72 to 75
H-2 4.04 0.052 0.074
Transfer the sample to a 400-mL beaker, and cover.
E 536
an accepted reference material, if available, to determine that
Magnesium 2852 N O– . 20 1.5 0.8
the accuracy of results is satisfactory.
C H
2 2
ALUMINUM, CADMIUM, COPPER, IRON, LEAD,
21.1.1 Prepare the dilute standard solution, reference, and
AND MAGNESIUM BY THE ATOMIC ABSORPTION
calibration solutions in accordance with Section 23. Refer to
METHOD
the table in 23.1 for suggested initial concentrations.
21.1.2 Prepare the instrument for use in accordance with in
17. Scope
25.1. Measure the instrument response while aspirating the
17.1 This test method covers the determination of aluminum
reference solution, the lowest, and the two highest calibration
in concentrations from 0.002 to 0.5 %, cadmium from 0.001 to
solutions, performing the measurements in accordance with
0.5 %, copper from 0.001 to 1.3 %, iron from 0.003 to 0.1 %,
25.2.2 and 25.2.3.
lead from 0.002 to 1.6 %, and magnesium from 0.001 to 0.1 %.
21.1.3 Minimum Response—Calculate the difference be-
tween the readings of the two highest of the five equally spaced
18. Summary of Test Method
calibration solutions. This difference must be equal to or
18.1 A hydrochloric acid solution of the sample is aspirated
greater than the number of scale units specified in the table in
into the flame of an atomic absorption spectrophotometer. The
21.1. For purposes of this test method, the scale unit is defined
absorption of the resonance line energy from the spectrum of
as one in the least significant digit of the scale reading of the
each element is measured and compared with that of calibra-
most concentrated calibration solution.
tion solutions of the same element. The wavelengths of the
21.1.4 Curve Linearity—Calculate the difference between
spectral lines and other method parameters are tabulated in
the scale readings of the reference solution and the lowest of
21.1 for each element.
the five equally spaced calibration solutions. If necessary,
convert this difference and the difference calculated in 21.1.3 to
19. Concentration Range
absorbance units. Divide the difference for the highest interval
19.1 The concentration range for each element must be
by that for the lowest interval. This ratio must be equal to or
determined experimentally, because the optimum range will
greater than 0.70.
depend upon the individual instrument. If the optimum con-
21.1.5 If the instrument meets or surpasses the minimum
centration range and instrument parameters have been deter-
response and curve linearity criteria, the initial concentration
mined, proceed in accordance with in Section 25; otherwise,
range may be considered suitable. In this case, proceed in
determine the concentration range in accordance with in
accordance with 21.1.7; otherwise, proceed as follows:
Section 21.
21.1.6 If the minimum response is not achieved, prepare
20. Interferences
another dilute standard solution to provide a higher concentra-
20.1 The elements ordinarily present do not interfere if their tion range, and repeat 21.1.1-21.1.4. If the calibration curve
concentrations are under the maximum limits shown in 1.1. does not meet the linearity criterion, prepare another dilute
standard solution to provide a lower concentration range, and
21. Apparatus
repeat 21.1.1-21.1.4. If a concentration range cannot be found
for which both criteria can be met, do not use this test method
21.1 Atomic Absorption Spectrophotometer, equipped with
a premix burner, with facilities for using the oxidizer-fuel until the performance of the apparatus satisfies the require-
ments.
combinations listed in the following table. Use hollow-cathode
lamps operated in accordance with manufacturer’s recommen-
21.1.7 Instrument Stability—Calculate the calibration vari-
dations as sources for the spectral lines. The instrument may be
ability and reference variability as follows:
considered suitable for this test method if a concentration range
100 ( c 2 c¯
~ !
can be found for which the minimum response, calibration
V 5 2 (2)
S D
c
c¯ n 2 1
variability, and reference variability tabulated in the following
table can be met:
100 (~o 2 o¯!
V 5 (3)
S D
o
Minimum Calibra- Reference
c¯ n 2 1
Spectral Oxidizer- Standard Response, tion Vari- Variabil-
Element Line, Å Fuel Solution Units ability, % ity, %
where:
V 5 calibration variability,
Aluminum 3092 N O– “A” 9 3.5 2.0 c
c¯ 5 average absorbance value for the highest
C H “B” 25 1.0 0.5
2 2
calibration solution,
Cadmium 2288 Air– . 50 0.8 0.4 2
((c − c¯) 5 sum of the squares of the n differences
C H
2 2
between the absorbance readings on the
Copper 3247 Air– “A” 15 2.0 0.8
highest calibration solution and their aver-
C H “B” 50 0.8 0.4
2 2
age,
V 5 reference variability relative to c,
Iron 2483 Air– “A” 15 2.0 1.0
o
C H “B” 25 1.0 0.5
((o − c¯) 5 sum of the squares of the n differences
2 2
between the absorbance readings on the
Lead 2170 Air– “A” 10 2.0 1.5
reference solution and their average, and
C H “B” 30 1.0 0.4
2 2
E 536
22.5 Lead, Standard Solution (1 mL 5 1 mg Pb)—Transfer
n 5 number of readings taken on each solution.
1 g of lead (purity: 99.95 % min) to a 250-mL beaker, cover,
and add 50 mL of HNO (1+1). Boil gently to complete
21.1.8 If the variability of the readings of the highest 3
dissolution and to remove oxides of nitrogen. Cool and transfer
calibration and the reference solutions are not equal to or
to a 1-L volumetric flask. Add 50 mL of HNO , dilute to
smaller than the values specified in 21.1, the stability of the
volume, and mix. Store in a polyethylene bottle.
instrument must be improved before this test method may be
22.6 Magnesium, Standard Solution (1 mL 5 0.1 mg
used.
Mg)—Transfer 0.1 g of magnesium (purity: 99.95 % min) to a
250-mL beaker, cover, and add 25 mL of HCl (1+1). Boil
22. Reagents
gently to complete dissolution. Cool and transfer to a 1-L
22.1 Aluminum, Standard Solution (1 mL 5 1.00 mg Al)—
volumetric flask. Add 50 mL of HCl, dilute to volume, and
Transfer1gof aluminum (purity: 99.95 % min) to a 250-mL
mix. Store
...
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