ASTM D1845-86(2008)

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Designation: D1845 − 86 (Reapproved2008)
Standard Test Methods for
Chemical Analysis of Strontium Chromate Pigment
This standard is issued under the fixed designation D1845; 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 Department of Defense.
1. Scope 3. Significance and Use
3.1 These test methods may be used to confirm the stated
1.1 These test methods cover the chemical analysis of
strontium oxide and chromium oxide content of strontium
strontium chromate pigment.
chromate.
1.2 The analytical procedures appear in the following order:
Sections 4. Apparatus
4.1 Gooch crucible.
Strontium by the Strontium Sulfate Method 7 to 10
Chromium by the Thiosulfate Method 11 to 14
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
Mass Color and Tinting Strength 19 5.1 Reagent grade chemicals shall be used in all tests.
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 D1193.
2. Referenced Documents
6. Preparation of Sample
2.1 ASTM Standards:
6.1 Mix the sample thoroughly. Take a sufficient quantity
D185 Test Methods for Coarse Particles in Pigments
for chemical analysis and pass it through a No. 325 (4-µm)
D280 Test Methods for Hygroscopic Moisture (and Other
sieve.
Matter Volatile Under the Test Conditions) in Pigments
STRONTIUM BY THE STRONTIUM SULFATE
D387 Test Method for Color and Strength of Chromatic
METHOD
Pigments with a Mechanical Muller
D444 Test Methods for Chemical Analysis of Zinc Yellow
7. Reagents
Pigment (Zinc Chromate Yellow)
D1193 Specification for Reagent Water
7.1 Acetic Acid (glacial).
7.2 Ammonium Hydroxide (1+3)—Mix1volumeofconcen-
trated ammonium hydroxide (NH OH, sp gr 0.90) with 3
These test methods are under the jurisdiction of ASTM Committee D01 on
volumes of water.
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.31 on Pigment Specifications.
Current edition approved Feb. 1, 2008. Published February 2008. Originally
approved in 1961. Last previous edition approved in 2003 as D1845 – 86 (2003). Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D1845-86R08. 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 (2008)
7.3 Ethyl Alcohol, conforming to Formula No. 2B or No. 30 11.2 Potassium Iodide Solution (150 g per L)—Dissolve150
of the U.S. Bureau of Alcohol, Tobacco, and Firearms. g of potassium iodide (KI) in water and dilute to 1 L.
7.4 Hydrochloric Acid (1+1)—Mix equal volumes of con- 11.3 Sodium Thiosulfate Standard Solution (0.1 N)—
centrated hydrochloric acid (HCl, sp gr 1.19) and water. Dissolve 24.8 g of reagent grade Na S O ·5H O in recently
2 2 3 2
boiled water and dilute to 1 L with additional recently boiled
7.5 Sulfuric Acid (1+19)—Mix 1 volume of concentrated
water. To standardize, pipet 25 mL of the standard potassium
sulfuric acid (H SO , sp gr 1.84) with 19 volumes of water.
2 4
dichromate solution (exactly 0.1000 N) into a 250-mL Erlen-
meyer flask.Add 100 mL of water, 15 mL of potassium iodide
8. Procedure
solution, and 15 mL of concentrated hydrochloric acid (sp gr
8.1 Weigh to 0.1 mg about 0.5 g of the sample into a
1.19). Titrate the liberated iodine with sodium thiosulfate
400-mLbeaker.Add 40 mLof HCl (1+1) and heat the solution
solutionuntilthereddish-browncolorbecomesquitefaint.Add
to dissolve the pigment. Add 40 mL of ethyl alcohol until the
5 mL of starch solution and continue the titration dropwise
chromium is reduced, as this is indicated by a dark coloration
until the blue color changes to a pale green. Calculate the
of the solution. Add to the solution 100 mL of water and
normality of the sodium thiosulfate solution as follows:
sufficient NH OH (1+3) to form a slight pers
...