ASTM D934-80(1999)
(Practice)Standard Practices for Identification of Crystalline Compounds in Water-Formed Deposits By X-Ray Diffraction
Standard Practices for Identification of Crystalline Compounds in Water-Formed Deposits By X-Ray Diffraction
SCOPE
1.1 These practices provide for X-ray diffraction analysis of powdered crystalline compounds in water-formed deposits. Two are given as follows: Sections Practice A---Camera 12 to 21 Practice B---Diffractometer 22 to 30
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Designation: D 934 – 80 (Reapproved 1999)
Standard Practices for
Identification of Crystalline Compounds in Water-Formed
Deposits By X-Ray Diffraction
This standard is issued under the fixed designation D 934; 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.
1. Scope D2331 Practices for Preparation and Preliminary Testing of
Water-Formed Deposits
1.1 These practices provide for X-ray diffraction analysis of
E11 Specification for Wire-Cloth Sieves for Testing Pur-
powdered crystalline compounds in water-formed deposits.
poses
Two are given as follows:
Sections
3. Terminology
Practice A—Camera 12 to 21
Practice B—Diffractometer 22 to 30
3.1 Definitions—For definitions of terms used in these
practices, refer to Terminology D 1129.
1.2 Both practices yield qualitative identification of crystal-
line components of water-formed deposits for which X-ray
4. Summary of Practices
diffraction data are available or can be obtained. Greater
4.1 Powdered samples are irradiated with a monochromatic
difficulty is encountered in identification when the number of
X-ray beam of short wavelength (from about 0.05 to 0.25 nm).
crystalline components increases.
The X rays interact with the atoms in the crystal and are
1.3 Amorphous phases cannot be identified without special
scattered in a unique diffraction pattern which produces a
treatment. Oils, greases, and most organic decomposition
fingerprint of the crystal’s atomic or molecular structure. The
products are not identifiable.
analytical instrumentation used in X-ray diffraction includes
1.4 The sensitivity for a given component varies with a
the powder camera and the diffractometer (1), (2), (3), (4),
combination of such factors as density, degree of crystalliza-
(5).
tion, particle size, coincidence of strong lines of components
and the kind and arrangement of the atoms of the components.
5. Significance and Use
Minimum percentages for identification may therefore range
5.1 The identification of the crystalline structures in water-
from1to40%.
formed deposits assists in the determination of the deposit
1.5 This standard does not purport to address all of the
sources and mode of deposition. This information may lead to
safety concerns, if any, associated with its use. It is the
measures for the elimination or reduction of the water-formed
responsibility of the user of this standard to consult and
deposits.
establish appropriate safety and health practices and deter-
mine the applicability of regulatory limitations prior to use.
6. Purity of Reagents
Specific precautionary statements are given in Section 8 and
6.1 Reagent grade chemicals shall be used in all tests.
Note 20.
Unless otherwise indicated, it is intended that all reagents shall
conform to the specifications of the Committee on Analytical
2. Referenced Documents
Reagents of the American Chemical Society, where such
2.1 ASTM Standards:
2 specifications are available. Other grades may be used,
D887 Practices for Sampling Water-Formed Deposits
provided it is first ascertained that the reagent is of sufficiently
D933 Practice for Reporting Results of Examination and
2 high purity to permit its use without lessening the accuracy of
Analysis of Water-Formed Deposits
3 the determination.
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
Annual Book of ASTM Standards, Vol 14.02.
The boldface numbers in parentheses refer to the references listed at the end of
These practices are under the jurisdiction of ASTM Committee D19 on Water these practices.
and are the direct responsibility of Subcommittee D19.03 on Sampling of Water and Reagent Chemicals, American Chemical Society Specifications, American
Water-Formed Deposits, Surveillance of Water, and Flow Measurement of Water. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Current edition approved July 3, 1980. Published November 1980. Originally listed by the American Chemical Society, see Analar Standards for Laboratory
published as D934 – 47 T. Last previous edition D934 – 74. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Annual Book of ASTM Standards, Vol 11.02. and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 11.01. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 934
6.2 Purity of Water— Unless otherwise indicated, reference that certain crystallites may be plastically deformed during the
to water shall be understood to mean reagent water conforming grinding, the deposit can be subjected to dry-ice temperatures
to Specification D 1193, Type II. and then ground immediately. Grind hydrated samples under
alcohol, if indicated, to prevent structural damage.
7. Sampling
NOTE 1—Most materials found in water-formed deposits are suffi-
7.1 Collect the sample in accordance with Practices D 887.
ciently brittle to be reduced to 45 μm and this crystallite dimension will
7.2 A suitable amount of sample should be obtained so that
generally give good identifiable diffraction patterns. However, it may not
it is representative of the deposit under investigation.
always be practical or possible to reduce certain materials to 45 μm. Often
7.3 Deposits shall be removed and protected in such a way good diffraction results can be obtained from larger crystallite sizes (No.
200 mesh (75-μm) to No. 270 mesh (53-μm)). The only practical test for
that they remain as nearly as possible in their original states.
proper grain size is in reproducibility of diffraction line intensities. The
ideal grain size may be in the subsieve range as small as 1 μm, but
8. Safety Precautions
reduction to this size may be impractical.
8.1 The potential danger of high-voltage and X-ray radia-
tion makes it mandatory for anyone operating X-ray apparatus
11. Selective Segregation of Analytical Sample
to be thoroughly familiar with basic safety precautions.
11.1 Chemical and Physical Treatment of Samples—
8.2 Place colorful signs displaying the international radia-
Depending on the contents of the sample, it may or may not be
tion symbol near X-ray equipment.
necessary to concentrate or segregate components by chemical
8.3 When X-ray equipment is producing radiation, illumi-
or physical treatment (see Note 2). Many crystalline materials
nate a conspicuous light. There should be no X rays if the bulb
produce sharp diffraction patterns and they are identifiable
burns out. Equipment without this feature can be modified.
when present to 1 or 2 % in a mixture. Other substances that
8.4 Use a portable counter periodically to test for leakage of
can be readily identified alone are difficult to detect in mixtures
X rays from equipment. Lead or lead glass shielding is
even when they are present to the extent of 50%. Separation of
sometimes needed. X rays of shorter wavelength require more
phases by density, acid solubility, or magnetic properties
caution.
followed by diffraction analysis of the separated phase(s) may
8.5 Film badges, dosimeters, or other monitoring devices
help to identify various deposit components. Separation treat-
shall be worn by personnel who regularly work with X-ray
ment is also helpful in resolving line coincidence in complex
equipment.
mixtures. If concentration or segregation is not deemed neces-
9. Preliminary Testing of Analytical Sample
sary, disregard any treatment and proceed in accordance with
Section 10. When treatment is necessary, use one or more of
9.1 It may be advantageous and even necessary to perform
the following chemical or physical treatments described in 11.2
other analytical investigative methods to aid in the rapid
to 11.7. It must be pointed out that the treatments provide no
identification of crystalline components in water-formed de-
absolute separation, but serve only to concentrate or partially
posits. For other testing methods refer to Practices D 2331.
segregate specific components.
10. Preparation of Sample
NOTE 2—It should be emphasized that water-formed deposits often
10.1 Apparatus—The apparatus used for preparing the
occur in clearly defined layers and that physical separation at the time of
sample is as follows:
sampling is more advantageous than later treatment.
10.1.1 Mullite or Agate Mortar.
11.2 Water-Insoluble Fraction—This treatment removes the
10.1.2 Sieves—A series of sieves from No. 100 mesh
water soluble from the water insoluble components. Soluble
(150-μm) to No. 325 mesh (45-μm) as specified in Specifica-
constituents would include most sodium, potassium, and
tion E 11.
lithium compounds (see Note 3).
10.1.3 Soxhlet Extractor.
11.2.1 Weigh 0.5 g or more of sample that has been ground
10.2 Procedure—The following procedure is to be used in
and passed through a No. 100 mesh (150-μm) sieve. Add 100
preparing the sample:
mL of water to a beaker containing the powdered specimen.
10.2.1 Air-dry moist samples before grinding. If there is
Heat to boiling and then cool. Allow 30 min of reaction time,
special need to preserve the nature or composition of the
filter through a 45-μm membrane filter, wash, and air-dry the
original deposit, special handling must be observed. Handle
residue. Regrind to pass through a No. 325 mesh (45-μm)
deliquescent deposits in a dry-box atmosphere. Handle samples
sieve.
subject to oxidation in an inert atmosphere.
10.2.2 If samples contain oil or grease, prepare a
NOTE 3—The filtrate may be evaporated and the residue examined by
chloroform-insoluble fraction by first drying the specimen for
diffraction. Although the crystalline structure may have changed from the
1 h at 105°C and then extracting for 2 h using chloroform in a original sample, it is often helpful in identifying simplified variations of
the original crystals. Sodium phosphate compounds found dispersed in
Soxhlet extracting apparatus. Air-dry to remove solvent from
boiler deposits are often noncrystalline or are so complex that they are not
specimen.
easily identified. The water soluble residue from these deposits after
10.2.3 Grind the sample in a mullite or agate (mechanical or
evaporation is often more easily identified.
hand) mortar until approximately 98 % passes a No. 325 mesh
(45-μm) sieve (see Note 1). Remove fragments of fiber, wood, 11.3 Hydrochloric Acid-Insoluble Fraction—This treatment
and metal. If the specimen is not sufficiently brittle at ordinary removes carbonates, phosphates, and hydroxides. Partial de-
temperatures to be ground to a fine powder or if it is suspected composition occurs to some silicates such as serpentine,
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 934
xonotlite, and analcite. Components such as anhydrite undergo 11.7 Brittle Fraction— This treatment concentrates the
only partial dissolution. more brittle or friable components from those that are less
brittle or less friable such as calcite from silica.
11.3.1 Reagent—The reagent used for this treatment is as
11.7.1 Apparatus—The apparatus necessary for this treat-
follows:
ment is as follows:
11.3.1.1 Hydrochloric Acid (1 + 6)—Mix 1 volume of con-
11.7.1.1 Electrical Mechanical Sieve Shaker.
centrated HCl (sp gr 1.19) with 6 volumes of water.
11.7.2 Weigh 0.5 g or more of sample and hand grind in a
11.3.2 Weigh approximately 0.5 g of the sample that has
mullite mortar until the largest particle size is approximately 1
been ground and passed through a No. 100 mesh (150-μm)
mm in diameter. Set up the sieve-shaker apparatus with four
sieve. Add 100 ml of HCl (1 + 6) to a beaker containing the
different size sieves; No. 100 mesh (150-μm), No. 140 mesh
powdered specimen. Allow 30 min of reaction time, filter
(105-μm), No. 200 mesh (75-μm) and No. 325 mesh (45-μm).
through a membrane filter, wash and air-dry the residue.
Shake the sample for several minutes and then collect the
Regrind to pass through a No. 325 mesh (45-μm) sieve.
various fractions from each sieve. The most friable portion of
11.4 Nitric Acid-Insoluble Fraction—This treatment re-
the deposit should have passed to the bottom-most sieve. Each
moves all the components indicated in 11.3 in addition to
fraction may be examined separately after regrinding to pass a
copper and most copper compounds.
No. 325 mesh (45-μm) sieve.
11.4.1 Reagent—The reagent used for this treatment is as
follows:
PRACTICE A—CAMERA
11.4.1.1 Nitric Acid (1 + 13)—Mix 1 volume of concen-
12. Scope
trated HNO (sp gr 1.42) with 13 volumes of water).
12.1 This method covers the qualitative X-ray diffraction
11.4.2 Weigh 0.5 g or more of the sample which has been
analysis of powdered crystalline substances using photographic
ground and passed through a No. 100 mesh (150-μm) sieve.
film as the detector. The film-camera technique has the
Add 100 ml of HNO (1 + 13) to a beaker containing the
advantage of being less expensive initially and less costly to
powdered specimen. Allow 30 min of reaction time, filter
maintain. The camera practice permits the use of smaller
through a membrane filter, wash and air-dry the residue.
samples. Film cameras do not require the well-stabilized power
Regrind to pass through a No. 325 mesh (45-μm) sieve.
supply as electronic detection techniques do. Often faint
11.5 Density Fraction— This treatment separates com-
diffraction lines are more readily detected with film.
pounds in water-formed deposits which differ appreciably in
density such as copper oxide and calcite.
13. Summary of Practice A
11.5.1 Weigh 0.5 g or more of sample that has been ground
13.1 Practice A utilizes the Debye-Scherrer type camera. In
and passed through a 100 mesh (150-μm) sieve. Add 100 mL
this method a powdered sample is placed in the center of a
of water to a beaker containing the powdered specimen. Stir
camera cylinder and a narrow film is wrapped around the inner
the liquid with a mechanical stirrer, but do not use a magnetic
wall. A monochromatic X-ray beam is directed upon the
stirrer (Note 4). The denser particles will settle to the bottom
sample and the randomly oriented crystallites diffract the
and the less dense particles will remain suspended. With
incident beam into a set of concentric cones in accordance with
continued
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