ASTM D934-80(2003)
(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
SIGNIFICANCE AND USE
The identification of the crystalline structures in water-formed deposits assists in the determination of the deposit sources and mode of deposition. This information may lead to measures for the elimination or reduction of the water-formed deposits.
SCOPE
1.1 These practices provide for X-ray diffraction analysis of powdered crystalline compounds in water-formed deposits. Two are given as follows: SectionsPractice A-Camera 12 to 21Practice B-Diffractometer22 to 30
1.2 Both practices yield qualitative identification of crystalline components of water-formed deposits for which X-ray diffraction data are available or can be obtained. Greater difficulty is encountered in identification when the number of crystalline components increases.
1.3 Amorphous phases cannot be identified without special treatment. Oils, greases, and most organic decomposition products are not identifiable.
1.4 The sensitivity for a given component varies with a combination of such factors as density, degree of crystallization, particle size, coincidence of strong lines of components and the kind and arrangement of the atoms of the components. Minimum percentages for identification may therefore range from 1 to 40 %.
1.5 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8 and Note 20.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 934 – 80 (Reapproved 2003)
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 Analysis of Water-Formed Deposits
D1129 Terminology Relating to Water
1.1 These practices provide for X-ray diffraction analysis of
D1193 Specification for Reagent Water
powdered crystalline compounds in water-formed deposits.
D2331 Practices for Preparation and Preliminary Testing of
Two are given as follows:
Water-Formed Deposits
Sections
E11 Specification for Wire Cloth Sieves for Testing Pur-
Practice A—Camera 12 to 21
Practice B—Diffractometer 22 to 30
poses
1.2 Both practices yield qualitative identification of crystal-
3. Terminology
line components of water-formed deposits for which X-ray
3.1 Definitions—For definitions of terms used in these
diffraction data are available or can be obtained. Greater
practices, refer to Terminology D 1129.
difficulty is encountered in identification when the number of
crystalline components increases.
4. Summary of Practices
1.3 Amorphous phases cannot be identified without special
4.1 Powdered samples are irradiated with a monochromatic
treatment. Oils, greases, and most organic decomposition
X-ray beam of short wavelength (from about 0.05 to 0.25 nm).
products are not identifiable.
The X rays interact with the atoms in the crystal and are
1.4 The sensitivity for a given component varies with a
scattered in a unique diffraction pattern which produces a
combination of such factors as density, degree of crystalliza-
fingerprint of the crystal’s atomic or molecular structure. The
tion, particle size, coincidence of strong lines of components
analytical instrumentation used in X-ray diffraction includes
and the kind and arrangement of the atoms of the components.
the powder camera and the diffractometer (1), (2), (3), (4),
Minimum percentages for identification may therefore range
(5).
from1to40%.
1.5 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 The identification of the crystalline structures in water-
responsibility of the user of this standard to consult and
formed deposits assists in the determination of the deposit
establish appropriate safety and health practices and deter-
sources and mode of deposition. This information may lead to
mine the applicability of regulatory limitations prior to use.
measures for the elimination or reduction of the water-formed
Specific precautionary statements are given in Section 8 and
deposits.
Note 20.
6. Purity of Reagents
2. Referenced Documents
2 6.1 Reagent grade chemicals shall be used in all tests.
2.1 ASTM Standards:
Unless otherwise indicated, it is intended that all reagents shall
D887 Practices for Sampling Water-Formed Deposits
conform to the specifications of the Committee on Analytical
D933 Practice for Reporting Results of Examination and
Reagents of the American Chemical Society, where such
specifications are available. Other grades may be used,
These practices are under the jurisdiction of ASTM Committee D19 on Water
and are the direct responsibility of Subcommittee D19.03 on Sampling ofWater and
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, The boldface numbers in parentheses refer to the references listed at the end of
On-Line Water Analysis, and Surveillance of Water. these practices.
Current edition approved July 3, 1980. Published November 1980. Originally Reagent Chemicals, American Chemical Society Specifications, American
approved in 1947. Last previous edition approved in 1980 as D 934 – 80. 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. Pharmaceutical Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 934 – 80 (2003)
provided it is first ascertained that the reagent is of sufficiently (45-µm) sieve (see Note 1). Remove fragments of fiber, wood,
high purity to permit its use without lessening the accuracy of and metal. If the specimen is not sufficiently brittle at ordinary
the determination. temperatures to be ground to a fine powder or if it is suspected
6.2 Purity of Water— Unless otherwise indicated, reference that certain crystallites may be plastically deformed during the
towatershallbeunderstoodtomeanreagentwaterconforming
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 Asuitable 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.
that they remain as nearly as possible in their original states.
200 mesh (75-µm) to No. 270 mesh (53-µm)). The only practical test for
proper grain size is in reproducibility of diffraction line intensities. The
8. Safety Precautions
ideal grain size may be in the subsieve range as small as 1 µm, but
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.
8.2 Place colorful signs displaying the international radia-
11.1 Chemical and Physical Treatment of Samples—
tion symbol near X-ray equipment.
Depending on the contents of the sample, it may or may not be
8.3 When X-ray equipment is producing radiation, illumi-
necessary to concentrate or segregate components by chemical
nate a conspicuous light. There should be no X rays if the bulb
or physical treatment (see Note 2). Many crystalline materials
burns out. Equipment without this feature can be modified.
produce sharp diffraction patterns and they are identifiable
8.4 Use a portable counter periodically to test for leakage of
when present to 1 or 2 % in a mixture. Other substances that
X rays from equipment. Lead or lead glass shielding is
canbereadilyidentifiedalonearedifficulttodetectinmixtures
sometimes needed. X rays of shorter wavelength require more
even when they are present to the extent of 50%. Separation of
caution.
phases by density, acid solubility, or magnetic properties
8.5 Film badges, dosimeters, or other monitoring devices
followed by diffraction analysis of the separated phase(s) may
shall be worn by personnel who regularly work with X-ray
help to identify various deposit components. Separation treat-
equipment.
ment is also helpful in resolving line coincidence in complex
mixtures. If concentration or segregation is not deemed neces-
9. Preliminary Testing of Analytical Sample
sary, disregard any treatment and proceed in accordance with
9.1 It may be advantageous and even necessary to perform
Section 10. When treatment is necessary, use one or more of
other analytical investigative methods to aid in the rapid
thefollowingchemicalorphysicaltreatmentsdescribedin11.2
identification of crystalline components in water-formed de-
to 11.7. It must be pointed out that the treatments provide no
posits. For other testing methods refer to Practices D 2331.
absolute separation, but serve only to concentrate or partially
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.
10.1.2 Sieves—A series of sieves from No. 100 mesh 11.2 Water-Insoluble Fraction—This treatment removes the
(150-µm) to No. 325 mesh (45-µm) as specified in Specifica-
water soluble from the water insoluble components. Soluble
tion E 11. constituents would include most sodium, potassium, and
10.1.3 Soxhlet Extractor. lithium compounds (see Note 3).
10.2 Procedure—The following procedure is to be used in
11.2.1 Weigh 0.5 g or more of sample that has been ground
preparing the sample:
and passed through a No. 100 mesh (150-µm) sieve. Add 100
10.2.1 Air-dry moist samples before grinding. If there is
mL of water to a beaker containing the powdered specimen.
special need to preserve the nature or composition of the
Heat to boiling and then cool. Allow 30 min of reaction time,
original deposit, special handling must be observed. Handle
filter through a 45-µm membrane filter, wash, and air-dry the
deliquescentdepositsinadry-boxatmosphere.Handlesamples
residue. Regrind to pass through a No. 325 mesh (45-µm)
subject to oxidation in an inert atmosphere.
sieve.
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
Soxhlet extracting apparatus. Air-dry to remove solvent from
the original crystals. Sodium phosphate compounds found dispersed in
specimen.
boiler deposits are often noncrystalline or are so complex that they are not
10.2.3 Grindthesampleinamulliteoragate(mechanicalor
easily identified. The water soluble residue from these deposits after
hand) mortar until approximately 98 % passes a No. 325 mesh evaporation is often more easily identified.
D 934 – 80 (2003)
11.3 Hydrochloric Acid-Insoluble Fraction—This treatment of the beaker, swirl, and filter.Air-dry the residues and regrind
removes carbonates, phosphates, and hydroxides. Partial de- to pass through a No. 325 mesh (45-µm) sieve.
composition occurs to some silicates such as serpentine, 11.7 Brittle Fraction— This treatment concentrates the
xonotlite, and analcite. Components such as anhydrite undergo more brittle or friable components from those that are less
only partial dissolution. 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).
11.4.2 Weigh 0.5 g or more of the sample which has been
12.1 This method covers the qualitative X-ray diffraction
ground and passed through a No. 100 mesh (150-µm) sieve.
analysisofpowderedcrystallinesubstancesusingphotographic
Add 100 ml of HNO (1 + 13) to a beaker containing the
3 film as the detector. The film-camera technique has the
powdered specimen. Allow 30 min of reaction time, filter
advantage of being less expensive initially and less costly to
through a membrane filter, wash and air-dry the residue.
maintain. The camera practice permits the use of smaller
Regrind to pass through a No. 325 mesh (45-µm) sieve.
samples.Filmcamerasdonotrequirethewell-stabilizedpower
11.5 Density Fraction— This treatment separates com-
supply as electronic detection techniques do. Often faint
pounds in water-formed deposits which differ appreciably in
diffraction lines are more readily detected with film.
density such as copper oxide and calcite.
11.5.1 Weigh 0.5 g or more of sample that has been ground
13. Summary of Practice A
and passed through a 100 mesh (150-µm) sieve. Add 100 mL
13.1 PracticeAutilizes the Debye-Scherrer type camera. In
of water to a beaker containing the powdered specimen. Stir
this method a powdered sample is placed in the center of a
the liquid with a mechanical stirrer, but do not use a magnetic
camera cylinder and a narrow film is wrapped around the inner
stirrer (Note 4). The denser particles will settle to the bottom
wall. A monochromatic X-ray beam is directed upon the
and the less dense particles will remain suspended. With
sample and the randomly oriented crystallites diffract the
continued stirring, withdraw sufficient liquid and filter through
incidentbeamintoasetofconcentricconesinaccordancewith
amembranefilter.Varyingthespeedofthestirrerwillputmore
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.