ASTM D3280-85(2020)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3280 − 85 (Reapproved 2020)
Standard Test Methods for
Analysis of White Zinc Pigments
This standard is issued under the fixed designation D3280; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2. Referenced Documents
1.1 These test methods cover procedures for the analysis of 2.1 ASTM Standards:
white zinc pigments. D280 Test Methods for Hygroscopic Moisture (and Other
Matter Volatile Under the Test Conditions) in Pigments
1.2 The analytical procedures appear in the following order:
D1193 Specification for Reagent Water
Section
D1394 Test Methods for Chemical Analysis of White Tita-
Preparation of Sample 6
Zinc Oxide nium Pigments
Total Zinc, Using Diphenylamine as Internal Indicator 7
E11 Specification for Woven Wire Test Sieve Cloth and Test
Total Zinc, Using Uranyl Acetate as External Indicator 8
Sieves
Total Impurities 9
Total Sulfur 10
Moisture and Other Volatile Matter 11 3. Summary of Test Method
Leaded Zinc Oxide
3.1 Zinc Oxide:
Total Lead 12
Total Zinc 13
3.1.1 Total Zinc—Determined using diphenylamine as an
Total Sulfur 14
internal indicator and also using uranyl acetate as an external
Total Impurities 15
indicator. Total impurities are calculated.
Moisture and Other Volatile Matter 16
Water-Soluble Salts 17
3.1.2 Total Sulfur—Determined as BaSO and calculated to
Zinc Sulfide
sulfur.
Zinc Oxide 18
3.1.3 Moisture and Volatile Matter—Determined in accor-
Zinc Sulfide 19
Water-Soluble Salts 20
dance with Method A of Test Methods D280.
Moisture and Other Volatile Matter 21
Barium Sulfate 22 3.2 Leaded Zinc Oxide:
Titanium Dioxide 23
3.2.1 Total Lead—Determined as PbSO and calculated to
1.3 The values stated in SI units are to be regarded as the
percent PbO.
standard. The values given in parentheses are for information
3.2.2 Total Zinc—Determined on the filtrate from procedure
only.
in 13.2.1 in accordance with methods in Sections 7 or 8.
3.2.3 Total Sulfur—Determined as BaSO and calculated to
1.4 This standard does not purport to address all of the 4
percent SO .
safety concerns, if any, associated with its use. It is the 3
3.2.4 Total Impurities—Calculatedfromcompositionaldata.
responsibility of the user of this standard to establish appro-
3.2.5 Moisture and Other Volatile Matter—Determined in
priate safety, health, and environmental practices and deter-
accordance with Method A of Test Methods D280.
mine the applicability of regulatory limitations prior to use.
3.2.6 Water Soluble Salts—Determined gravimetrically.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.3 Zinc Sulfide:
ization established in the Decision on Principles for the
3.3.1 Total Zinc—Determined using uranyl acetate external
Development of International Standards, Guides and Recom-
indicator in accordance with Section 9.
mendations issued by the World Trade Organization Technical
3.3.2 Zinc Sulfide—Determined in accordance with Sections
Barriers to Trade (TBT) Committee.
8 or 9 and calculating ZnO to ZnS.
3.3.3 Water Soluble Salts—Determined in accordance with
Section 18.
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.31 on Pigment Specifications. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in 1973. Last previous edition approved in 2014 as D3280 – 85 (2014). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D3280-85R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3280 − 85 (2020)
3.3.4 Moisture—Determined in accordance with Method A mixed and a representative portion taken and powdered if
of Test Methods D280. lumpy or not finely ground. Mix the sample in all cases
3.3.5 Barium Sulfate—The sample is treated with N SO thoroughly before taking specimens for analysis.
2 4
and Na CO and the residue of BaCO is dissolved in NCl and
2 3 3
6.2 Separate pigments from paints or pastes, grind to a fine
(NH ) SO added to precipitate BaSO , which is weighed.
4 2 4 4
powder, pass through a 180-µm (No. 80) sieve (Note 1)to
3.3.6 Titanium Dioxide—Determined in accordance with
remove any skins, thoroughly mix, and oven dry at 105°C.
Test Methods D1394.
Moisten such pigments after weighing with a little alcohol
before adding reagents for analysis.
4. Significance and Use
NOTE 1—Detailed requirements for this sieve are given in Specification
4.1 White zinc pigments find considerable use in white
E11.
paints, and as such it is useful to formulators and users to be
6.3 Preserve all samples in stoppered bottles or containers.
able to monitor the amounts of these pigments in whole paints.
It is also of interest to raw material suppliers and paint
ZINC OXIDE
producers to check the specifications of each pigment.
7. Total Zinc, Using Diphenylamine as Internal Indicator
5. Reagents
7.1 Reagents:
5.1 Purity of Reagents—Reagent grade chemicals shall be
7.1.1 Diphenylamine Indicator Solution (10 g/L))—
used in all tests. Unless otherwise indicated, it is intended that
Dissolve1gof diphenylamine in 100 mL of H SO .
all reagents shall conform to the specifications of the Commit-
2 4
tee onAnalytical Reagents of theAmerican Chemical Society, 7.1.2 Potassium Ferrocyanide (1 mL = 0.008 g Zn)—
Dissolve 35 g of K Fe(CN) ·3H O in water and dilute to 1 L
where such specifications are available. Other grades may be
4 6 2
used, provided it is first ascertained that the reagent is of and add 0.3 g of potassium ferricyanide (K Fe(CN) ). Stan-
3 6
dardize the solution by titrating against zinc (320 to 340 mg),
sufficiently high purity to permit its use without lessening the
accuracy of the determination. following the procedure described in 7.2. Calculate the grams
of zinc equivalent to 1.00 mL of the solution.
5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean Type II reagent grade
7.2 Procedure—Weigh to 0.1 mg about 0.4 g of the sample
water conforming to Specification D1193.
into a tall form 400-mL beaker. Moisten with about 20 mL of
water, and dissolve in 15 mLof HCl. Neutralize with NH OH,
5.3 Concentration of Reagents:
usinglitmusastheindicator.Addanexcessof15mLofH SO
2 4
5.3.1 Concentrated Acids and Ammonium Hydroxide—
(1+2) and dilute to 200 mL. Heat to approximately 60°C, add
When acids and ammonium hydroxide are specified by name
2 drops of diphenylamine indicator solution and while stirring
or chemical formula only it should be understood that concen-
vigorously, titrate with K Fe(CN) solution to the color change
4 6
trated reagents of the following specific gravities or concen-
from purple to a persistent yellowish green.
trations are intended:
Acetic acid, HC H O 99.5 % NOTE 2—The true end point is a sharp, persistent change from a purple
2 3 2
Hydrochloric acid, HCl sp gr 1.19
to a yellowish green. At the beginning of the titration, a deep blue color
Hydrofluoric acid, HF 48 %
is developed after addition of a few millilitres of K Fe(CN) solution.
4 6
Nitric acid, HNO sp gr 1.42
About 0.5 to 1.0 mL before the true end point is reached, the solution
Sulfuric acid, H SO sp gr 1.84
2 4
changes from a blue to a purple color.After the purple color is developed,
Ammonium hydroxide, NH OH sp gr 0.90
the titration should be continued dropwise to the persistent yellowish
The desired specific gravities or concentrations of all other
green end point.
concentrated acids are stated whenever they are specified.
7.3 Calculation—Calculate the percent total zinc as ZnO, A,
5.3.2 Diluted Acids and Ammonium Hydroxide—
as follows:
Concentrations of diluted acids and ammonium hydroxide,
V Z 31.245
except when standardized, are specified as a ratio stating the 2
A 5 3100 (1)
F G
S
number of volumes of the concentrated reagents to be diluted 1
with a given number of volumes of water, as in the following
where:
example: HCl (1+99) means 1 volume of concentrated HCl (sp
V =K Fe(CN) solution required for titration of the
2 4 6
gr 1.19) diluted with 99 volumes of water.
specimen, mL,
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
6. Preparation of Sample
S = specimen weight, and
6.1 Grind dry pigments, if lumpy or not finely ground, to a
1.245 = molecular weight ZnO (81.38)/molecular weight Zn
fine powder for analysis. Large samples may be thoroughly
(65.38).
8. Total Zinc, Using Uranyl Acetate as External Indicator
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
8.1 Reagents:
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
8.1.1 Uranyl Acetate Indicator Solution (50 g/L)—Dissolve
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
5gofUO (C H O ) ·2H O in 100 mL of water and make
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma- 2 2 3 2 2 2
copeial Convention, Inc. (USPC), Rockville, MD. slightly acid with acetic acid.
D3280 − 85 (2020)
8.1.2 Potassium Ferrocyanide, Standard Solution (1 expelled, cool, and add 3 to5gof granular aluminum. Heat to
mL = 0.008 g Zn)—Prepare and standardize as in 7.1.2. Run a boiling, filter, and wash well with hot water.
blank titration with the same amounts of reagents and water. 10.2.2 Dilute the filtrate to 300 mL with water, neutralize
Calculate the zinc equivalent of the solution as follows: with NH OH, and add 6 drops of HCl. Heat to boiling and add
25 mL of hot BaCl solution dropwise, with constant stirring.
Z 5 W/ V 2 B (2)
~ !
Allow to stand in a warm place for at least 2 h.
where:
10.2.3 Filter, using a weighed Gooch crucible, or a fine
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
textured filter paper and wash well with hot water. Dry and
4 6
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 BaSO .
mL, and
10.3 Calculation—Calculate the percent sulfur, A, as fol-
B =K Fe(CN) solution required for titration of the blank,
4 6
lows:
mL.
~P 30.1374!
8.2 Procedure: A 5 3100 (5)
F G
S
8.2.1 Weigh to 0.1 mg about 0.4 g of the sample into a
where:
tall-form 400-mL beaker. Moisten with about 20 mL of water
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, weight BaSO (233.43).
4 6 4
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
8.2.2 Blank—Run a blank titration with the same amounts
matter in accordance with Method A of Test Methods D280.
of reagents and water.
LEADED ZINC OXIDE
8.3 Calculation—Calculate the percent total zinc as ZnO, A,
as follows:
12. Total Lead
V 2 B Z 31.245
~~ ! ! 12.1 Procedure:
A 5 3100 (3)
F G
S 12.1.1 Weightothenearest0.1mgabout0.5gofthesample
into a 400-mLbeaker. Dissolve in 250 mLof water and 20 mL
where:
of HNO (Note 2).Add5mLofH SO and evaporate to dense
3 2 4
V =K Fe(CN) solution required for titration of the
4 6
white fumes. Cool, add 50 mLof 95 % alcohol and 200 mLof
sample, mL,
water,andletstandcold1to2h.Filter,usingaweighedGooch
S = sample used, g, and
crucible.Wash the precipitate with H SO (1+99) and combine
2 4
1.245 = molecular weight ZnO (81.38)/molecular weight Zn
the filtrate and washings. If the zinc content of the sample is
(65.38).
known to be 40 % or over, reserve the filtrate and washings for
the determination of total zinc (Section 13).
9. Total Impurities
NOTE 3—If the sample contains calcium or barium, the lead and zinc
9.1 Calculation—Calculate the percent total impurities, A,
should be separated by precipitation with H S after solution in HCl,
as follows:
making alkaline with NH OH and then acid with acetic acid. Dissolve the
PbS and ZnS in dilute HNO and determine the lead and zinc as above.
A 5 100 2 L1Z 1S (4)
~ !
1 5
12.1.2 Ignite the precipitate in the crucible at dull red heat
where:
(550 6 50°C) for 20 min, cool, and weigh.
L = total lead as PbO, %,
12.2 Calculation—Calculate the percent total lead as PbO,
Z = total zinc as ZnO, %, and
A, as follows:
S = total sulfur as SO,%.
5 3
P 30.736
~ !
A 5 3100 (6)
F G
10. Total Sulfur S
10.1 Reagents:
where:
10.1.1 Bromine Water (saturated).
P = PbSO precipitate, g,
1 4
10.1.2 Aluminum—Reagent grade granular aluminum.
S = sample used, g, and
10.1.3 Barium Chloride Solution (100 g BaCl L)—Dissolve 0.736 = molecular weight PbO (223.21)/molecular weight
117 g BaCl ·2H O in water and dilute to 1 L. PbSO (303.28).
2 2
10.2 Procedure:
13. Total Zinc
10.2.1 Weigh to 0.1 g about 10 g of the sample into a 400-
13.1 Reagents—See 7.1 or 8.1, whichever is applicable.
mL beaker.Add 50 mL of saturated bromine water, 100 mL of
water, and 35 mL of HCl. Boil until all the bromine has been 13.2 Procedure:
D3280 − 85 (2020)
13.2.1 If the zinc content of the sample is known to be 40 % temperature and shake for 10 min. Dilute the solution to the
or over, determine zinc on the filtrate obtained in 12.1.1.Ifthe mark with water, mix by shaking, and filter through a dry, fine
zinc content is known to be under 40 %, weigh to the nearest paper.
0.1 mg about1gofthe sample, precipitate and filter off the 17.1.2 Transfer 400 mL of the clear filtrate to a weighed
leadasPbSO asdescribedin12.1.1,anddeterminezinconthe platinum dish and evaporate to dryness at 105 6 2°C, cool in
filtrate. a desiccator, and weigh rapidly.
17.1.3 Blank—Make a blank determination at the same time
13.2.2 Evaporate the appropriate filtrate to dryness and
dete
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