ASTM D3280-85(1999)
(Test Method)Standard Test Methods for Analysis of White Zinc Pigments
Standard Test Methods for Analysis of White Zinc Pigments
SCOPE
1.1 These test methods cover procedures for the analysis of white zinc pigments.
1.2 The analytical procedures appear in the following order: Section Preparation of Sample 6 Zinc Oxide Total Zinc, Using Diphenylamine as Internal Indicator 7 Total Zinc, Using Uranyl Acetate as External Indicator 8 Total Impurities 9 Total Sulfur 10 Moisture and Other Volatile Matter 11 Leaded Zinc Oxide Total Lead 12 Total Zinc 13 Total Sulfur 14 Total Impurities 15 Moisture and Other Volatile Matter 16 Water-Soluble Salts 17 Zinc Sulfide Zinc Oxide 18 Zinc Sulfide 19 Water-Soluble Salts 20 Moisture and Other Volatile Matter 21 Barium Sulfate 22 Titanium Dioxide 23
1.3 This standard does not purport to address the safety problems 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 .
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Designation: D 3280 – 85 (Reapproved 1999)
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.
1. Scope D 1394 Test Methods for Chemical Analysis of White
Titanium Pigments
1.1 These test methods cover procedures for the analysis of
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
white zinc pigments.
poses
1.2 The analytical procedures appear in the following order:
Section
3. Summary of Test Methods
Preparation of Sample 6
Zinc Oxide
3.1 Zinc Oxide:
Total Zinc, Using Diphenylamine as Internal Indicator 7
3.1.1 Total Zinc—Determined using diphenylamine as an
Total Zinc, Using Uranyl Acetate as External Indicator 8
internal indicator and also using uranyl acetate as an external
Total Impurities 9
Total Sulfur 10
indicator. Total impurities are calculated.
Moisture and Other Volatile Matter 11
3.1.2 Total Sulfur—Determined as BaSO and calculated to
Leaded Zinc Oxide
sulfur.
Total Lead 12
Total Zinc 13
3.1.3 Moisture and Volatile Matter—Determined in accor-
Total Sulfur 14
dance with Method A of Test Methods D 280.
Total Impurities 15
3.2 Leaded Zinc Oxide:
Moisture and Other Volatile Matter 16
Water-Soluble Salts 17
3.2.1 Total Lead—Determined as PbSO and calculated to
Zinc Sulfide
percent PbO.
Zinc Oxide 18
Zinc Sulfide 19 3.2.2 Total Zinc—Determined on the filtrate from procedure
Water-Soluble Salts 20
in 13.1.1 in accordance with methods in Sections 8 or 9.
Moisture and Other Volatile Matter 21
3.2.3 Total Sulfur—Determined as BaSO and calculated to
Barium Sulfate 22
percent SO .
Titanium Dioxide 23
3.2.4 Total Impurities—Calculated from compositional
1.3 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-
D 280 Test Methods for Hygroscopic Moisture (and Other
2 tions 8 or 9 and calculating ZnO to ZnS.
Matter Volatile Under the Test Conditions) in Pigments
3.3.3 Water Soluble Salts—Determined in accordance with
D 1193 Specification for Reagent Water
Section 18.
3.3.4 Moisture—Determined in accordance with Method A
of Test Methods D 280.
These test methods are under the jurisdiction of ASTM Committee D-1 on Paint 3.3.5 Barium Sulfate—The sample is treated with N SO
2 4
and Related Coatings, Materials, and Applications and are the direct responsibility
and Na CO and the residue of BaCO is dissolved in NCl and
2 3 3
of Subcommittee D01.31 on Pigment Specifications.
(NH ) SO added to precipitate BaSO , which is weighed.
4 2 4 4
Current edition approved Oct. 25, 1985. Published December 1985. Originally
e2
published as D 3280 – 73. Last previous edition D 3280 – 73 (1979) .
Annual Book of ASTM Standards, Vol 06.03.
3 4
Annual Book of ASTM Standards, Vol 11.01. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3280
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 5 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 on Analytical Reagents of the American 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 6.2. 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 mL of HCl. Neutralize with NH OH,
water conforming to Specification D 1193.
using litmus as the indicator. Add an excess of 15 mL of 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—Calculate the percent total zinc as ZnO, 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 5 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 5 zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
S 5 specimen weight, and
6. Preparation of Sample
1.245 5 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 5 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.
D 3280
10.2.3 Filter, using a weighed Gooch crucible, or a fine
Z 5 zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
textured filter paper and wash well with hot water. Dry and
W 5 zinc used,
ignite in a muffle furnace for 30 min. Cool and weigh as
V 5 K Fe(CN) solution required for titration of the zinc,
4 6
mL, and BaSO .
B 5 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 5 BaSO precipitate, g,
slightly alkaline to litmus paper. Add HCl until just acid, and
S 5 specimen weight, g, and
then add 3 mL in excess. Dilute to about 250 mL with hot water
0.1374 5 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 min. 11.1 Procedure—Determine moisture and other volatile
matter in accordance with Method A of Test Methods D 280.
8.2.2 Blank—Run a blank titration with the same amounts
of reagents and water.
LEADED ZINC OXIDE
8.3 Calculat
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