ASTM D50-90(2011)
(Test Method)Standard Test Methods for Chemical Analysis of Yellow, Orange, Red, and Brown Pigments Containing Iron and Manganese
Standard Test Methods for Chemical Analysis of Yellow, Orange, Red, and Brown Pigments Containing Iron and Manganese
SIGNIFICANCE AND USE
These test methods compile in one place, recommended procedures for analyzing inorganic colored pigments. These pigments are used extensively in paints, and for this reason their compositions are important to the formulators and user.
SCOPE
1.1 These test methods cover procedures for the chemical analysis of yellow, orange, red, and brown pigments containing iron and manganese. The test methods apply specifically to the following pigments: synthetic hydrated yellow iron oxide, yellow ocher, red and brown iron oxides, raw and burnt umber, raw and burnt sienna, and venetian red.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D50 − 90 (Reapproved 2011)
Standard Test Methods for
Chemical Analysis of Yellow, Orange, Red, and Brown
Pigments Containing Iron and Manganese
ThisstandardisissuedunderthefixeddesignationD50;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
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 priate safety and health practices and determine the applica-
bility of regulatory limitations prior to us.
1.1 These test methods cover procedures for the chemical
analysisofyellow,orange,red,andbrownpigmentscontaining
2. Referenced Documents
iron and manganese. The test methods apply specifically to the
2.1 ASTM Standards:
following pigments: synthetic hydrated yellow iron oxide,
C25 Test Methods for Chemical Analysis of Limestone,
yellow ocher, red and brown iron oxides, raw and burnt umber,
Quicklime, and Hydrated Lime
raw and burnt sienna, and venetian red.
D185 Test Methods for Coarse Particles in Pigments
1.2 The analytical procedures appear in the following order:
D280 Test Methods for Hygroscopic Moisture (and Other
ASTM
Matter Volatile Under the Test Conditions) in Pigments
Method
D562 Test Method for Consistency of Paints Measuring
Refer-
Dry Pigments Sections ences
KrebsUnit(KU)ViscosityUsingaStormer-TypeViscom-
eter
Moisture and Other Volatile Matter 6 D280
D1193 Specification for Reagent Water
Loss on Ignition 7
Coarse Particles 8 D185 D1208 Test Methods for Common Properties of Certain
Matter Soluble in Water 9 D1208
Pigments
Organic Coloring Matter 10
E11 Specification for Woven Wire Test Sieve Cloth and Test
Iron Oxide 11 and 12
Calcium Compounds (Reported as CaO) 13 and 14
Sieves
Sulfates Soluble in Hydrochloric Acid 15 and 16
Lead Chromate (in Ochers) 17
3. Significance and Use
Calcium Carbonate (in Venetian Red) 18 C25
Manganese (in Siennas and Umbers) 19 and 20
3.1 These test methods compile in one place, recommended
procedures for analyzing inorganic colored pigments. These
Pigment Pastes in Oil
pigments are used extensively in paints, and for this reason
Pigment Content 21 D1208
their compositions are important to the formulators and user.
Moisture and Other Volatile Matter 22 D1208
Nonvolatile Matter in Vehicle 23
4. Preparation of Sample
Moisture by Distillation 24 D1208
Coarse Particles and Skins 25 D185
4.1 Mix the sample thoroughly and take a representative
Consistency (Stormer) 26 D562
portion for analysis. Reduce any lumps or coarse particles to a
1.3 The values stated in SI units are to be regarded as
fine powder by grinding. Grind extracted pigments to pass a
standard. No other units of measurement are included in this
No. 80 (180-µm) sieve (see Specification E11 for detailed
standard.
requirements). Discard any skins that do not pass through the
1.4 This standard does not purport to address all of the
sieve. Mix the finely ground pigment thoroughly.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 5. Purity of Reagents
5.1 Purity of Reagents—Unless otherwise indicated, it is
intended that all reagents shall conform to the specifications of
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
Current edition approved June 1, 2011. Published June 2011. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin1917.Lastpreviouseditionapprovedin2005asD50 – 90 (2005).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D0050-90R11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D50 − 90 (2011)
theCommitteeonAnalyticalReagentsoftheAmericanChemi- organic coloring matter is indicated (Note 2). If the solutions
cal Society, where such specifications are available. Other remain colorless, organic colors are probably absent, but may
grades may be used, provided it is first ascertained that the be tested for by reference to procedures given in standard
reagent is of sufficiently high purity to permit its use without reference works, taking into account the nature of the pigment
lessening the accuracy of the determination. involved.
5.2 Purity of Water—Unless otherwise indicated, references
NOTE 2—With this class of pigments indication of presence of an
organic color may often be noted by the characteristic odor given off on
to water shall be understood to mean Type II reagent water
ignition.
conforming to Specification D1193.
Iron Oxide
DRY PIGMENTS
Moisture and Other Volatile Matter
11. Reagents
6. Procedure
11.1 Stannous Chloride Solution (SnCl ·2H O)—Dissolve
2 2
50 g of SnCl ·2H O in 300 mL of hydrochloric acid (HCl) (sp
6.1 Determine moisture and other volatile matter in accor- 2 2
gr 1.19) and dilute with water to 500 mL. Keep the clear
dance with Method A of Test Methods D280.
solution in a tightly stoppered bottle containing some metallic
Loss on Ignition
tin.
11.2 Mercuric Chloride Solution (HgCl )—Prepare a satu-
7. Procedure
rated solution of HgCl (60 to 100 g/L).
7.1 Weigh accurately approximately1gof pigment into a
11.3 Sulfuric-Phosphoric Acid Mixture—Mix 150 mL of
previously weighed and ignited porcelain crucible (Note 1).
sulfuric acid (H SO ) (sp gr 1.84) with 150 mL of phosphoric
2 4
Cover and ignite to constant weight over a bunsen or Meker
acid (H PO ) (85 %) and dilute with water to 1 L.
3 4
burner or in an electric furnace at a temperature of approxi-
mately 900°C. Cool in a desiccator, weigh, and calculate the
11.4 Diphenylamine Indicator—Dissolve1gof diphe-
percent loss on ignition. This figure may include combined nylamine in 100 mL of H SO (sp gr 1.84).
2 4
water, carbon dioxide (CO ), organic matter, and some sulfuric
11.5 Standard Potassium Dichromate Solution (K Cr O )
2 2 7
oxide (SO ) if much calcium sulfate (CaSO ) is present. The
3 4
(0.1 N)—Dissolve 4.904 g of K Cr O in water and dilute to 1
2 2 7
CO may be determined on a separate portion if desired.
L. Standardize against the National Institute of Standards and
Technology standard sample No. 27 of Sibley iron ore.
NOTE 1—It is inadvisable to use platinum unless it is known that
attacking substances are absent.
11.6 Potassium Ferricyanide Solution (K Fe(CN) )—
3 6
Optional. Dissolve approximately 0.01 g of K Fe(CN) in 50
Coarse Particles 3 6
mL of water. This solution must be made fresh when wanted
8. Procedure
because it does not keep.
8.1 Determine coarse particles in accordance with Test
12. Procedure
Methods D185.
12.1 According to the amount of iron in the pigment, weigh
Matter Soluble in Water
0.3 to 1.0 g of the pigment and ignite in a porcelain crucible at
a dull red heat to destroy organic matter. Transfer to a 400-mL
9. Procedure
beaker and add 25 mL of HCl (sp gr 1.19). Cover with a
9.1 Determine matter soluble in water in accordance with
watchglassanddigestjustshortofboiling(80to90°C)untilno
Test Methods D1208.
dark specks can be seen in the insoluble residue. The addition
of a few drops of SnCl solution after adding the acid greatly
Organic Coloring Matter
assistsdissolvingoftheiron.Whentheresidueislightincolor,
thesolutionofironmaybeconsideredcomplete.Thismaytake
10. Procedure
from 15 min to 1 h, or longer.
10.1 Boil2gofthe sample with 25 mL of water, let settle,
12.2 Add 25 to 50 mL of water and heat to gentle boiling
and decant the supernatant liquid. Boil the residue with 25 mL
(avoid vigorous prolonged boiling). Slowly add SnCl solution
of ethyl alcohol (95 %) and decant as before. Boil the residue
dropwiseuntilthelastdropmakesthesolutioncolorlessorfree
with 25 mL of 1 N alcoholic sodium hydroxide (NaOH)
from any tinge of yellow, then add 1 or 2 drops in excess. It is
solution and again decant. Boil another 2-g portion of the
best to keep the watchglass on the beaker while adding the
sample with 25 mL of chloroform, let settle, and decant the
SnCl solution,withagitationofthehotironsolutionaftereach
supernatant liquid. If any one of the above solutions is colored,
addition.IftoomuchSnCl isaddedbymistake,addpotassium
permanganate (KMnO ) to the solution until a yellow color
Reagent Chemicals, American Chemical Society Specifications, American
appears, then again add SnCl dropwise until the yellow color
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, Reference may be made to the following: Payne, H. F., “Organic Coatings
MD. Technology,” Vol II, John Wiley & Sons, Inc., New York, N. Y., 1961.
D50 − 90 (2011)
justdisappears,againaddingoneortwodropsinexcess.Dilute 13.4 Calculate the calcium oxide (CaO) value of the solu-
with 200 mL of cold water; then add all at once with vigorous tion as follows:
stirring 15 mLof HgCl solution. Let stand 3 to 4 min.Aslight
C 5 W 3 V 30.4185 (2)
~ !
1 1
white precipitate should form. If none, or a heavy grayish
where:
precipitate forms, the determination should be discarded and
C = CaO equivalent of the KMnO solution, g/mL,
repeated.
W = sodium oxalate used, g, and
12.3 Add 15 mL of H SO -H PO mixture and 3 drops of
2 4 3 4
V = KMnO solution required for the titration, mL.
1 4
diphenylamine indicator solution. Titrate with K Cr O
2 2 7
0.4185 5 CaO/Na C O 5 56.08/134.01 (3)
solution, taking the sudden change of the dark green color to a
2 2 4
blue-black color as the end point.
14. Procedure
12.4 If preferred, K Fe(CN) may be used as an external
3 6
14.1 Weigh 2.5 g of sample, transfer to a porcelain crucible,
indicator. In this case omit the addition of the H SO -H PO
2 4 3 4
and ignite at a dull red heat to destroy organic matter. Cool,
mixture and the diphenylamine indicator. Titrate with the
transfer to a 600-mL beaker, and add 100 mL of HCl (1 + 1).
K Cr O solution as in 12.3, except toward the end take out a
2 2 7
Digest just short of boiling until no dark specks can be seen in
very small drop of the solution being titrated and touch this to
the insoluble residue.Add ammonium hydroxide (NH OH) (sp
a drop of the K Fe(CN) solution, best placed on a
...
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