ASTM D444-88(2020)
(Test Method)Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
SIGNIFICANCE AND USE
3.1 This test method has been developed to standardize the chemical analysis of zinc chromate yellow pigment and to provide alternate methods of analysis for chromium and zinc.
SCOPE
1.1 These test methods cover procedures for the chemical analysis of the pigment known commercially as “zinc yellow” or “zinc chromate yellow.”
1.2 The analytical procedures appear in the following order:
Sections
Moisture and Other Volatile Matter
7
Combined Water
8
Chromium:
Dichromate Method
9 – 11
Thiosulfate Method
9, 12, and 13
Zinc:
Hydroxyquinoline Method
9, 14, and 15
Ferrocyanide Method
9, 16, and 17
Alkaline Salts
18 and 19
Sulfates
20 and 21
Chlorides
22 and 23
Matter Insoluble in Dilute Acetic
Acid
24
Coarse Particles
25
1.3 The values stated in SI units are to be considered the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
General Information
Relations
Standards Content (Sample)
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: D444 − 88 (Reapproved 2020)
Standard Test Methods for
Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate
Yellow)
This standard is issued under the fixed designation D444; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 These test methods cover procedures for the chemical
analysis of the pigment known commercially as “zinc yellow”
2. Referenced Documents
or “zinc chromate yellow.”
2.1 ASTM Standards:
1.2 The analytical procedures appear in the following order:
D185 Test Methods for Coarse Particles in Pigments
Sections
D280 Test Methods for Hygroscopic Moisture (and Other
Moisture and Other Volatile Matter 7
Matter Volatile Under the Test Conditions) in Pigments
Combined Water 8
D478 Specification for Zinc Yellow (Zinc Chromate) Pig-
Chromium:
Dichromate Method 9–11
ments
Thiosulfate Method 9, 12, and 13
D1193 Specification for Reagent Water
Zinc:
Hydroxyquinoline Method 9, 14, and 15 E11 Specification for Woven Wire Test Sieve Cloth and Test
Ferrocyanide Method 9, 16, and 17
Sieves
Alkaline Salts 18 and 19
E50 Practices for Apparatus, Reagents, and Safety Consid-
Sulfates 20 and 21
Chlorides 22 and 23 erations for Chemical Analysis of Metals, Ores, and
Matter Insoluble in Dilute Acetic 24
Related Materials
Acid
Coarse Particles 25
3. Significance and Use
1.3 The values stated in SI units are to be considered the
3.1 This test method has been developed to standardize the
standard. The values given in parentheses are for information
chemical analysis of zinc chromate yellow pigment and to
only.
provide alternate methods of analysis for chromium and zinc.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4. Preparation of Sample
responsibility of the user of this standard to establish appro-
4.1 Mix the laboratory sample thoroughly. Take a sufficient
priate safety, health, and environmental practices and deter-
quantity for the chemical analyses and pass it through a
mine the applicability of regulatory limitations prior to use.
180-µm (No. 80) sieve, grinding in a mortar if necessary.
1.5 This international standard was developed in accor-
NOTE 1—Detailed requirements for this sieve are given in Specification
dance with internationally recognized principles on standard-
E11.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. 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, 2020. Published June 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1937. Last previous edition approved in 2014 as D444 – 88 (2014). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D0444-88R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D444 − 88 (2020)
solution is not clarified by this treatment, extract a portion of the original
theCommitteeonAnalyticalReagentsoftheAmericanChemi-
sample with a solvent such as chloroform before the analysis is begun.
cal Society, where such specifications are available. Other
grades may be used, provided it is first ascertained that the
CHROMIUM BY THE DICHROMATE TEST
reagent is of sufficiently high purity to permit its use without
METHOD
lessening the accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references 10. Reagents
to water for use in the preparation of reagents and in analytical
10.1 Ferrous Ammonium Sulfate Solution—Dissolve 80 g of
procedures shall conform to Type II reagent water, in Specifi-
ferrous ammonium sulfate (FeSO · (NH ) SO ·6H O) in 50
4 4 2 4 2
cation D1193.
mL of H SO (sp gr 1.84) and enough water to make 1 L of
2 4
solution. Mix thoroughly before use. This solution is approxi-
6. Precision
mately 0.2 N.
6.1 Precision statements have not been established.
10.2 Ortho-Phenanthroline Indicator Solution—0.5 % in
MOISTURE AND OTHER VOLATILE MATTER
water.
10.3 Potassium Dichromate, Standard Solution—(0.1 N)—
7. Procedure
Dissolve 4.9035 g of dried potassium dichromate (K Cr O )in
2 2 7
7.1 Determine moisture and other volatile matter in accor-
water and dilute to 1 L in a volumetric flask.
dance with Test Method A of Test Methods D280.
11. Procedure
COMBINED WATER
11.1 Pipet50mLofthesolutionofthespecimen(Section7)
8. Procedure
into a 600-mLbeaker.Add 200 to 250 mLof water and 10 mL
8.1 Weigh to 0.1 mg3gofthe oven-dried material from the
of H SO (sp gr 1.84). Cool to 35°C or below.
2 4
determinationofmoistureandothervolatilematter(Note2and
11.2 Add an excess of ferrous ammonium sulfate solution
Note 3), and place in a porcelain boat. Introduce the boat with
and back-titrate with 0.1 N K Cr O solution, using ortho-
2 2 7
the charge into a refractory combustion tube in an electrically-
phenanthroline indicator. Carry out a blank titration of the
heated combustion furnace of the type used for the determina-
sameamountofferrousammoniumsulfatesolutionatthesame
tion of carbon in steel by direct combustion (Note 4). Place the
time and in the same manner.
boat at the center of the combustion tube maintained at a
temperature of 1000°C for 4 h. Draw a current of pure dry air
11.3 Calculation—Calculate the percent of chromium C as
or dry nitrogen through the tube to sweep the evolved moisture CrO , as follows:
into a previously weighed absorption tube containing anhy-
C 5 B 2 V N 30.03334/S 3100
~ !
1 1 1 1
drous magnesium perchlorate (Mg(ClO ) ) or other efficient
4 2
where:
desiccant. The weight increase of the absorption tube repre-
sents the “combined water.” B =K Cr O solution required for titration of the
1 2 2 7
blank, mL,
NOTE 2—Loss on ignition of the pigment does not suffice for the
V =K Cr O solution required for back-titration of
1 2 2 7
determination of combined water in zinc yellow.
the specimen, mL,
NOTE 3—If the pigment contains an organic treating agent, first remove
N = normality of the K Cr O solution, and
this treating agent by washing with ether or chloroform.
1 2 2 7
NOTE 4—See Apparatus No. 1 for the determination of total carbon by
S = specimen in the aliquot used, g.
direct combustion as described in Practices E50.
0.03334 = milliequivalents weight of CrO .
SPECIMEN SOLUTION FOR DETERMINATION OF 11.4 Alternatively, the solution of the specimen may be
CHROMIUM AND ZINC titrated directly with the ferrous ammonium sulfate solution,
using an electrometric titration assembly to detect the end
9. Procedure
point. Standardize the ferrous solution against K Cr O .
2 2 7
9.1 Weigh to 0.1 mg about a 4-g specimen and mix with 50
CHROMIUM BY THE THIOSULFATE TEST
mL of cold sulfuric acid (H SO ) (1+5). It should dissolve
2 4
METHOD
completelyatthisstage(Note5).Dilutethesolutionto500mL
in a volumetric flask.
12. Reagents
NOTE 5—A cloudy solution may result if the pigment contains a
12.1 Potassium Iodide Solution (150 g/L)—Dissolve 150 g
surface-treating agent. In this case, it usually can be cleared by cooling in
an ice-bath and filtering through a medium porosity fritted disk. If the of potassium iodide (KI) in water and dilute to 1 L.
12.2 Sodium Thiosulfate, Standard Solution (0.1 N)—
Dissolve 24.8 g of sodium thiosulfate of (Na S O ·5H O) in
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
2 2 3 2
Standard-Grade Reference Materials, American Chemical Society, Washington,
1 L of freshly boiled and cooled water contained in a sterile
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
glass bottle. If sulfur precipitates during preparation or upon
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
subsequent use, discard the solution and prepare a new one.
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
copeial Convention, Inc. (USPC), Rockville, MD. Standardize against iodine.
D444 − 88 (2020)
misleading. The insoluble reagent will dissolve in a hot solution and also
12.3 Starch Indicator Solution—Stir up 2 to3gof potato
in an excess of alcohol or acetone, whereas the zinc oxyquinolate will not.
starch with 100 mL salicylic acid solution (1 %), and boil the
mixture until the starch is practically dissolved, then dilute to 15.3 Dry the precipitate at 165°C for at least 2 h and weigh
1 L with water. as zinc oxyquinolate.
15.4 Calculation—Calculate the percent zinc A as zinc
13. Procedure
oxide (ZnO), as follows:
13.1 Pipet a 25-mL aliquot of the solution of the specimen
A 5 @~P 30.2303!/S # 3100
(Section 9) into a 500-mLglass-stoppered Erlenmeyer iodime-
tricflaskorothersuitableglass-stopperedbottlecontaining200 where:
mL of H SO (1+39). Add 20 mL of KI solution (150 g/L),
2 4 P = zinc oxyquinolate, g, and
stopper, and allow the solution to stand for approximately 5
S = specimen in aliquot used, g.
min.
0.2303 = ZnO/zinc oxyquinolate = 81.38⁄353.37
13.2 Titratetheliberatediodinewith0.1 NNa S O solution
2 2 3
ZINC BY THE FERROCYANIDE TEST METHOD
at room temperature until the reddish brown iodine color
becomes quite faint.Add 5 mL of starch solution and continue
16. Reagents
the titration until the final color change becomes pale green
16.1 Methyl Orange Indicator Solution—Dissolve 0.1 g of
with no blue tinge. Titrate this final titration by swirling the
methyl orange in 100 mL of water.
flask at least three times after each addition of the Na S O
2 2 3
16.2 Potassium Ferrocyanide, Standard Solution—Dissolve
solution, being sure that there is no further color change,
22 g of potassium ferrocyanide (K Fe(CN)·3H O) in water
especially at the final stage of the titration.The green end point 4 6 2
and dilute to 1 L.To standardize, transfer 0.2 g of metallic zinc
is definite and sharp.
or freshly ignited ZnO to a 400-mL beaker. Dissolve in 10 mL
13.3 Calculation—Calculate the percent of chromium C as
of hydrochloric acid (HCl, sp gr 1.19) and 20 mL of water.
CrO as follows:
Drop in a small piece of litmus paper, add ammonium
C 5 V N 30.03334 /S 3100
@~ ! #
hydroxide (NH OH) until slightly alkaline, then add HCl until
2 2 2
just acid, and then 3 mL more of HCl. Dilute to about 250 mL
where:
with hot water and heat nearly to boiling. Run in the
V =Na S O solution required for titration of the
2 2 2 3
K Fe(CN) solution slowly from a buret, while stirring
4 6
specimen, mL
constantly, until a drop tested on a white porcelain plate with a
N = normality of the Na S O solution, and
2 2 2 3
drop of the uranyl indicator solution shows a brown tinge after
S = specimen in the aliquot used, g.
standing 1 min. Do not allow the temperature of the solution to
fall below 70°C during the titration. Run a blank using the
ZINC BY THE HYDROXYQUINOLINE TEST
same amounts of reagents and water as in the standardization.
METHOD
The standardization must be made under the same conditions
(Suitable if No Interfering Substances Are Present)
of temperature, volume, and acidity as obtained when the
specimen is titrated. Calculate the strength of the K Fe(CN)
14. Reagents
4 6
solution in terms of grams of zinc as follows:
14.1 Acetone Solution of 8-Hydroxyquinoline (50 g/L)—
Z 5 W/ V 2 B
~ !
Dissolve5gof 8-hydroxyquinoline in 100 mL of acetone. 3 2
where:
15. Procedure
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
15.1 Pipet50mLofthesolutionofthespecimen(Section9)
W = zinc used (or equivalent to the ZnO used), g,
into a 250-mL beaker and dilute to 100 mL with water. Add 5
V =K Fe(CN) solution required for titration of the
3 4 6
to 10 g of ammonium chloride (NH Cl) and heat to boiling.
standard, g, and
Add a slight excess of ammonium hydroxide (NH OH) and let
B =K Fe(CN) solution required for titration of the blank,
2 4 6
standafewminutestoallowanyprecipitatetocoagulate.Filter
mL.
through an ashless, rapid paper into a 400-mL beaker and
16.3 Thymol Blue Indicator Solution (0.5 g/L)—Dissolve
wash.
0.1 g of thymol blue indicator in 200-mLof methanol, ethanol,
15.2 Heatthefiltratetoboilingandadd5mLofNH OH(sp
or isopropanol.
gr 0.90). Add dropwise 10 mL of the acetone solution of
16.4 Uranyl Acetate Indicator Solution (50 g/L)—Dissolve
8-hydroxyquinoline (Note 6). Let stand 10 to 20 min and filter
5gofUO (C H O ) ·H O in water made slightly acid with
2 2 3 2 2 2
through a medium-porosity sintered-glass crucible. Wash well
acetic acid and dilute to 100 mL.
with water.
17. Procedure
NOTE 6—The reagent is used in acetone solution rather than alcohol
solution to eliminate the danger of reducing some of the chromate by
17.1 Pipet50mLofthesolutionofthespecimen(Section9)
alcohol. Avoid adding an excess of reagent and lengthy boiling after its
into a 400-mL beaker. Add 35 mL of H SO (1+5) and 3 to 4
2 4
addition. Ten millilitres of hydroxyquinoline (50 g/L) is sufficient for a
drops of thymol blue indicator solution. First add NH OH (sp
normal zinc yellow. The solution can be tested for complete precipitation, 4
but since the reagent itself is rather insoluble, the results may be gr 0.90) and finally NH OH (1+10) until the color of the
D444 − 88 (2020)
indicator changes to a salmon shade intermediate between pink 19.5 Add about 2 mL of H SO (1+1) to the filtrate,
2 4
and yellow.This gives a pH of about 2.4. Dilute the solution to evaporate to dryness, and again ignite gently. During the
300 mL and heat to just under boiling. Pass in HSata ignition process add small portions of solid ammonium car-
moderate rate for 40 min. Allow the precipitate to settle for 1 bonate ((NH ) CO ). Cool in a desiccator and weigh.
4 2 3
h and filter. Wash the filter ten times with water saturated with
19.6 Test the residue for calcium. If pres
...
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