ASTM D3280-85(2004)e1

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e1
Designation:D3280–85(Reapproved2004)
Standard Test Methods for
Analysis of White Zinc Pigments
This standard is issued under the fixed designation D 3280; 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.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Editorial corrections were made in 3.2.2, 7.1.2, and Eq 2 in August 2006.
1. Scope D 280 Test Methods for Hygroscopic Moisture (and Other
Matter Volatile Under the Test Conditions) in Pigments
1.1 These test methods cover procedures for the analysis of
D 1193 Specification for Reagent Water
white zinc pigments.
D 1394 Test Methods for Chemical Analysis of White
1.2 The analytical procedures appear in the following order:
Titanium Pigments
Section
E11 Specification for Wire Cloth and Sieves for Testing
Preparation of Sample 6
Zinc Oxide
Purposes
Total Zinc, Using Diphenylamine as Internal Indicator 7
Total Zinc, Using Uranyl Acetate as External Indicator 8
3. Summary of Test Methods
Total Impurities 9
Total Sulfur 10
3.1 Zinc Oxide:
Moisture and Other Volatile Matter 11
3.1.1 Total Zinc—Determined using diphenylamine as an
Leaded Zinc Oxide
internal indicator and also using uranyl acetate as an external
Total Lead 12
Total Zinc 13
indicator. Total impurities are calculated.
Total Sulfur 14
3.1.2 Total Sulfur—Determined as BaSO and calculated to
Total Impurities 15
sulfur.
Moisture and Other Volatile Matter 16
Water-Soluble Salts 17
3.1.3 Moisture and Volatile Matter—Determined in accor-
Zinc Sulfide
dance with Method A of Test Methods D 280.
Zinc Oxide 18
Zinc Sulfide 19 3.2 Leaded Zinc Oxide:
Water-Soluble Salts 20
3.2.1 Total Lead—Determined as PbSO and calculated to
Moisture and Other Volatile Matter 21
percent PbO.
Barium Sulfate 22
3.2.2 Total Zinc—Determined on the filtrate from procedure
Titanium Dioxide 23
in 13.2.1 in accordance with methods in Sections 7 or 8.
1.3 The values stated in SI units are to be regarded as the
3.2.3 Total Sulfur—Determined as BaSO and calculated to
standard. The values given in parentheses are for information
percent SO .
only.
3.2.4 Total Impurities—Calculated from compositional
1.4 This standard does not purport to address all of the
data.
safety concerns, if any, associated with its use. It is the
3.2.5 Moisture and Other Volatile Matter—Determined in
responsibility of the user of this standard to establish appro-
accordance with Method A of Test Methods D 280.
priate safety and health practices and determine the applica-
3.2.6 Water Soluble Salts—Determined gravimetrically.
bility of regulatory limitations prior to use.
3.3 Zinc Sulfide:
3.3.1 Total Zinc—Determined using uranyl acetate external
2. Referenced Documents
indicator in accordance with Section 9.
2.1 ASTM Standards:
3.3.2 Zinc Sulfide—Determined in accordance with Sec-
tions 8 or 9 and calculating ZnO to ZnS.
These test methods are under the jurisdiction of ASTM Committee D01 on
3.3.3 Water Soluble Salts—Determined in accordance with
Paint and Related Coatings, Materials, and Applications and are the direct
Section 18.
responsibility of Subcommittee D01.31 on Pigment Specifications.
3.3.4 Moisture—Determined in accordance with Method A
Current edition approved Nov. 1, 2004. Published November 2004. Originally
approved in 1973. Last previous edition approved in 1999 as D 3280 – 85 (1999). of Test Methods D 280.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.3.5 Barium Sulfate—The sample is treated with N SO
2 4
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and Na CO and the residue of BaCO is dissolved in NCl and
2 3 3
Standards volume information, refer to the standard’s Document Summary page on
(NH ) SO added to precipitate BaSO , which is weighed.
the ASTM website.
4 2 4 4
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D3280–85 (2004)
3.3.6 Titanium Dioxide—Determined in accordance with Moisten such pigments after weighing with a little alcohol
Test Methods D 1394. before adding reagents for analysis.
NOTE 1—Detailed requirements for this sieve are given in Specification
4. Significance and Use
E11.
4.1 White zinc pigments find considerable use in white
6.3 Preserve all samples in stoppered bottles or containers.
paints, and as such it is useful to formulators and users to be
able to monitor the amounts of these pigments in whole paints.
ZINC OXIDE
It is also of interest to raw material suppliers and paint
producers to check the specifications of each pigment.
7. Total Zinc, Using Diphenylamine as Internal Indicator
5. Reagents 7.1 Reagents:
7.1.1 Diphenylamine Indicator Solution (10 g/L)—Dissolve
5.1 Purity of Reagents—Reagent grade chemicals shall be
1 g of diphenylamine in 100 mL of H SO .
2 4
used in all tests. Unless otherwise indicated, it is intended that
7.1.2 Potassium Ferrocyanide (1 mL = 0.008 g Zn)—
all reagents shall conform to the specifications of the Commit-
Dissolve 35 g of K Fe(CN) ·3H O in water and dilute to 1 L
4 6 2
tee onAnalytical Reagents of theAmerican Chemical Society,
and add 0.3 g of potassium ferricyanide (K Fe(CN) ). Stan-
3 6
where such specifications are available. Other grades may be
dardize the solution by titrating against zinc (320 to 340 mg),
used, provided it is first ascertained that the reagent is of
following the procedure described in 7.2. Calculate the grams
sufficiently high purity to permit its use without lessening the
of zinc equivalent to 1.00 mL of the solution.
accuracy of the determination.
7.2 Procedure—Weigh to 0.1 mg about 0.4 g of the sample
5.2 Purity of Water—Unless otherwise indicated, references
into a tall form 400-mL beaker. Moisten with about 20 mL of
to water shall be understood to mean Type II reagent grade
water, and dissolve in 15 mLof HCl. Neutralize with NH OH,
water conforming to Specification D 1193.
using litmus as the indicator.Add an excess of 15 mLof H SO
5.3 Concentration of Reagents: 2
4 (1+2) and dilute to 200 mL. Heat to approximately 60°C, add
5.3.1 Concentrated Acids and Ammonium Hydroxide—
2 drops of diphenylamine indicator solution and while stirring
When acids and ammonium hydroxide are specified by name
vigorously, titrate with K Fe(CN) solution to the color change
4 6
or chemical formula only it should be understood that concen-
from purple to a persistent yellowish green.
trated reagents of the following specific gravities or concen-
trations are intended:
NOTE 2—The true end point is a sharp, persistent change from a purple
Acetic acid, HC H O 99.5 % to a yellowish green. At the beginning of the titration, a deep blue color
2 3 2
Hydrochloric acid, HCl sp gr 1.19
is developed after addition of a few millilitres of K Fe(CN) solution.
4 6
Hydrofluoric acid, HF 48 %
About 0.5 to 1.0 mL before the true end point is reached, the solution
Nitric acid, HNO sp gr 1.42
changes from a blue to a purple color.After the purple color is developed,
Sulfuric acid, H SO sp gr 1.84
2 4
the titration should be continued dropwise to the persistent yellowish
Ammonium hydroxide, NH OH sp gr 0.90
green end point.
The desired specific gravities or concentrations of all other
7.3 Calculation—CalculatethepercenttotalzincasZnO, A,
concentrated acids are stated whenever they are specified.
as follows:
5.3.2 Diluted Acids and Ammonium Hydroxide—
V Z 3 1.245
Concentrations of diluted acids and ammonium hydroxide, 2
A 5 3 100 (1)
F G
S
except when standardized, are specified as a ratio stating the
number of volumes of the concentrated reagents to be diluted
where:
with a given number of volumes of water, as in the following
V =K Fe(CN) solution required for titration of the
2 4 6
example: HCl (1+99) means 1 volume of concentrated HCl (sp
specimen, mL,
gr 1.19) diluted with 99 volumes of water.
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
S = specimen weight, and
6. Preparation of Sample
1.245 = molecular weight ZnO (81.38)/molecular weight
6.1 Grind dry pigments, if lumpy or not finely ground, to a
Zn (65.38).
fine powder for analysis. Large samples may be thoroughly
mixed and a representative portion taken and powdered if
8. Total Zinc, Using Uranyl Acetate as External Indicator
lumpy or not finely ground. Mix the sample in all cases
8.1 Reagents:
thoroughly before taking specimens for analysis.
8.1.1 Uranyl Acetate Indicator Solution (50 g/L)—Dissolve
6.2 Separate pigments from paints or pastes, grind to a fine
5gofUO (C H O ) ·2H O in 100 mL of water and make
2 2 3 2 2 2
powder, pass through a 180-µm (No. 80) sieve (Note 1)to
slightly acid with acetic acid.
remove any skins, thoroughly mix, and oven dry at 105°C.
8.1.2 Potassium Ferrocyanide, Standard Solution (1
mL = 0.008 g Zn)—Prepare and standardize as in 7.1.2. Run a
blank titration with the same amounts of reagents and water.
Reagent Chemicals, American Chemical Society Specifications, American
Calculate the zinc equivalent of the solution as follows:
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Z 5 W/~V 2 B! (2)
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
where:
MD.
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D3280–85 (2004)
10.2.3 Filter, using a weighed Gooch crucible, or a fine
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
textured filter paper and wash well with hot water. Dry and
W = zinc used,
ignite in a muffle furnace for 30 min. Cool and weigh as
V =K Fe(CN) solution required for titration of the zinc,
4 6
mL, and BaSO .
B =K Fe(CN) solution required for titration of the blank, 10.3 Calculation—Calculate the percent sulfur, A, as fol-
4 6
mL.
lows:
8.2 Procedure:
P 3 0.1374
~ !
A 5 3 100 (5)
F G
S
8.2.1 Weigh to 0.1 mg about 0.4 g of the sample into a 2
tall-form 400-mL beaker. Moisten with about 20 mL of water
where:
and dissolve by adding 10 mL of HCl. Add NH OH until
P = BaSO precipitate, g,
slightly alkaline to litmus paper. Add HCl until just acid, and
S = specimen weight, g, and
thenadd3mLinexcess.Dilutetoabout250mLwithhotwater
0.1374 = molecular weight of sulfur (32.064)/molecular
and heat nearly to boiling. Titrate with K Fe(CN) solution,
4 6 weight BaSO (233.43).
stirring constantly, until a drop of uranyl acetate indicator
11. Moisture and Other Volatile Matter
tested in a white porcelain spot plate shows a brown tinge after
standing 1
...