ASTM D1845-86(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D1845–86(Reapproved2003)
Standard Test Methods for
Chemical Analysis of Strontium Chromate Pigment
This standard is issued under the fixed designation D 1845; 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 3. Significance and Use
1.1 These test methods cover the chemical analysis of 3.1 These test methods may be used to confirm the stated
strontium chromate pigment. strontium oxide and chromium oxide content of strontium
1.2 The analytical procedures appear in the following order: chromate.
Sections
4. Apparatus
Strontium by the Strontium Sulfate Method 7to10
4.1 Gooch crucible.
Chromium by the Thiosulfate Method 11to14
4.2 Electric Furnace, capable of 800°C.
Chloride Content 15
Sulfate Content 16
Moisture and Other Volatile Matter 17
5. Purity of Reagents
Coarse Particles 18
5.1 Reagent grade chemicals shall be used in all tests.
Mass Color and Tinting Strength 19
Unless otherwise indicated, it is intended that all reagents shall
1.3 This values stated in SI units are to be considered the
conform to the specifications of the Committee on Analytical
standard. The values given in parentheses are for information
Reagents of the American Chemical Society, where such
only.
specifications are available. Other grades may be used, pro-
1.4 This standard does not purport to address the safety
vided it is first ascertained that the reagent is of sufficiently
concerns associated with its use. It is the responsibility of the
high purity to permit its use, without lessening the accuracy of
user of this standard to establish appropriate safety and health
the determination.
practices and determine the applicability of regulatory limita-
5.2 Unless otherwise indicated, references to water shall be
tions prior to use.
understood to mean Type II of Specification D 1193.
2. Referenced Documents
6. Preparation of Sample
2.1 ASTM Standards:
6.1 Mix the sample thoroughly. Take a sufficient quantity
D 185 Test Methods for Coarse Particles in Pigments
for chemical analysis and pass it through a No. 325 (4-µm)
D 280 Test Methods for Hygroscopic Moisture (and Other
sieve.
Matter Volatile Under the Test Conditions) in Pigments
D 387 Test Method for Color and Strength of Chromatic
STRONTIUM BY THE STRONTIUM SULFATE
Pigments with a Mechanical Muller
METHOD
D 444 Test Methods for Chemical Analysis of Zinc Yellow
7. Reagents
Pigment (Zinc Chromate Yellow)
D 1193 Specification for Reagent Water
7.1 Acetic Acid (glacial).
7.2 Ammonium Hydroxide (1+3)—Mix 1 volume of con-
centrated ammonium hydroxide (NH OH, sp gr 0.90) with 3
volumes of water.
These test methods are under the jurisdiction of ASTM Committee Paint and
Related Coatings, Materials, and Applications and are the direct responsibility of
Subcommittee D01.31 on Pigment Specifications.
Current edition approved Dec. 1, 2003. Published December 2003. Originally Reagent Chemicals, American Chemical Society Specifications, American
approved in 1961. Last previous edition approved in 1986 as D 1845 – 86 (1999). Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
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D1845–86 (2003)
7.3 Ethyl Alcohol, conforming to Formula No. 2B or No. 30 11.3 Sodium Thiosulfate Standard Solution (0.1 N)—
of the U.S. Bureau of Alcohol, Tobacco, and Firearms. Dissolve 24.8 g of reagent grade Na S O ·5H O in recently
2 2 3 2
7.4 Hydrochloric Acid (1+1)—Mix equal volumes of con- boiled water and dilute to 1 L with additional recently boiled
centrated hydrochloric acid (HCl, sp gr 1.19) and water. water. To standardize, pipet 25 mL of the standard potassium
7.5 Sulfuric Acid (1+19)—Mix 1 volume of concentrated dichromate solution (exactly 0.1000 N) into a 250-mL Erlen-
sulfuric acid (H SO , sp gr 1.84) with 19 volumes of water. meyer flask.Add 100 mL of water, 15 mL of potassium iodide
solution, and 15 mL of concentrated hydrochloric acid (sp gr
8. Procedure
1.19). Titrate the liberated iodine with sodium thiosulfate
8.1 Weigh to 0.1 mg about 0.5 g of the sample into a solutionuntilthereddish-browncolorbecomesquitefaint.Add
400-mLbeaker.Add 40 mLof HCl (1+1) and heat the solution
5 mL of starch solution and continue the titration dropwise
to dissolve the pigment. Add 40 mL of ethyl alcohol until the until the blue color changes to a pale green. Calculate the
chromium is reduced, as this is indicated by a dark coloration
normality of the sodium thiosulfate solution as follows:
of the solution. Add to the solution 100 mL of water and
2.5000
N 5
sufficient NH OH (1+3) to form a slight persistent precipitate.
4 M
8.2 Add HCl dropwise until the prec
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