ASTM D1245-84(2007)
(Practice)Standard Practice for Examination of Water-Formed Deposits by Chemical Microscopy
Standard Practice for Examination of Water-Formed Deposits by Chemical Microscopy
SIGNIFICANCE AND USE
Chemical composition of water-formed deposits is a major indicator of proper or improper chemical treatment of process water, and is often an indicator of operational parameters as well, for example, temperature control. This practice allows for rapid determination of constituents present in these deposits, particularly those indications of improper water treatment, since they usually have very distinctive and easily recognized optical properties.
This practice, where applicable, eliminates the need for detailed chemical analysis, which is time-consuming, and which does not always reveal how cations and anions are mutually bound.
Qualitative use of this practice should be limited to those deposits whose control is generally known or predictable, based on treatment and feedwater mineral content, and whose constituents are crystalline, or in other ways optically or morphologically distinctive. If these criteria are not met, other techniques of analysis should be used, such as Practice D 2332 or Test Methods D 3483, or both.
Quantitative use of this practice should be limited to estimates only. For more precise quantitative results, other methods should be used (see 5.3).
SCOPE
1.1 This practice describes a procedure for the examination of water-formed deposits by means of chemical microscopy. This practice may be used to complement other methods of examination of water-formed deposits as recommended in Practices D 2331 or it may be used alone when no other instrumentation is available or when the sample size is very small.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D 1245–84 (Reapproved 2007)
Standard Practice for
Examination of Water-Formed Deposits by Chemical
Microscopy
This standard is issued under the fixed designation D 1245; 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 3.2 Descriptions of Terms Specific to This Standard—
Certaintermsinthispracticethatrelatespecificallytochemical
1.1 This practice describes a procedure for the examination
microscopy are described as follows:
of water-formed deposits by means of chemical microscopy.
3.2.1 anisotropic—having different optical properties in
This practice may be used to complement other methods of
different optical planes. These planes are referred to as the
examination of water-formed deposits as recommended in
alpha, beta, and omega axes.
Practices D 2331 or it may be used alone when no other
3.2.2 Becke line—a faint, halo-like line that surrounds a
instrumentation is available or when the sample size is very
crystal when the crystal is mounted in an oil of different
small.
refractiveindex.Itincreasesinintensityasthedifferenceinthe
1.2 This standard does not purport to address all of the
refractive index between the crystal and the oil increases.
safety concerns, if any, associated with its use. It is the
3.2.3 dispersion—the variation of index of refraction with
responsibility of the user of this standard to establish appro-
wavelength.
priate safety and health practices and determine the applica-
3.2.4 dispersion staining—the color effects produced when
bility of regulatory limitations prior to use.
a transparent object, immersed in a liquid having a refractive
2. Referenced Documents
indexnearthatoftheobjectisviewedunderthemicroscopeby
transmitted white light and precise aperture control.
2.1 ASTM Standards:
3.2.5 extinction angle—the angle between the extinction
D 887 Practices for Sampling Water-Formed Deposits
position and some plane, edge, or line in a crystal.
D 1129 Terminology Relating to Water
3.2.6 extinction position—the position in which an aniso-
D 1193 Specification for Reagent Water
tropic crystal, between crossed polars, exhibits complete dark-
D 2331 Practices for Preparation and PreliminaryTesting of
ness.
Water-Formed Deposits
3.2.7 index of refraction—the numerical expression of the
D 2332 Practice for Analysis of Water-Formed Deposits by
ratio of the velocity of light in a vacuum to the velocity of light
Wavelength-Dispersive X-Ray Fluorescence
in a substance.
D 3483 Test Methods for Accumulated Deposition in a
3.2.8 isotropic—having the same optical properties in all
Steam Generator Tube
directions.
3. Terminology
3.2.9 petrographic—pertaining to the description of rocks
or rocklike substances. Such description is usually in terms of
3.1 Definitions—For definitions of terms in this practice
morphology and optical properties.
relating specifically to water and water-formed deposits, refer
3.2.10 solid solution—a homogeneous mixture of two or
to Terminology D 1129.
more components, in the solid state, retaining substantially the
structure of one of the components.
1 4. Summary of Practice
This practice is under the jurisdiction of ASTM Committee D19 on Water and
is the direct responsibility of Subcommittee D19.03 on Sampling Water and
4.1 The practice is essentially chemical microscopical,
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use,
supplemented by optical data obtained by the petrographic
On-Line Water Analysis, and Surveillance of Water.
method. The identification of compounds is made by observ-
Current edition approved Dec. 1, 2007. Published January 2008. Originally
approved in 1952. Last previous edition approved in 2003 as D 1245 – 84 (2003).
ing, under the microscope, characteristic reactions and precipi-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tates resulting from the action of specific reagents on the solid
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
sample or solutions thereof, and by measuring the optical
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. properties.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 1245–84 (2007)
5. Significance and Use below the condenser and the other just above the objective;
43,103, and 453 objectives; and 53 and 103 eyepieces
5.1 Chemical composition of water-formed deposits is a
fitted with crosshairs.The optic axis of the microscope shall be
major indicator of proper or improper chemical treatment of
adjustable so that it can be brought into coincidence with the
process water, and is often an indicator of operational param-
centerofrotationoftherevolvingstage.ABertrand-Amicilens
eters as well, for example, temperature control. This practice
equipped with an iris diaphragm, or a sliding stop ocular, shall
allows for rapid determination of constituents present in these
be used for viewing interference figures. A quartz wedge,
deposits, particularly those indications of improper water
gypsum plate, and standard mica plate are necessary external
treatment, since they usually have very distinctive and easily
accessories. Aperture stops are necessary for observing the
recognized optical properties.
color effects of dispersion, that is, dispersion staining. A
5.2 This practice, where applicable, eliminates the need for
cardboard “washer” in the objective and a cover glass with a
detailed chemical analysis, which is time-consuming, and
centered dried drop of India ink are sufficient; however, a
which does not always reveal how cations and anions are
device is available commercially.
mutually bound.
7.11 Porcelain Crucibles, No. 0.
5.3 Qualitative use of this practice should be limited to
7.12 Reagent Bottles for Immersion Liquids—Glass drop-
thosedepositswhosecontrolisgenerallyknownorpredictable,
ping bottles of 30-mLcapacity.These bottles shall be equipped
based on treatment and feedwater mineral content, and whose
with groundglass stoppers with dropping rods integral with the
constituents are crystalline, or in other ways optically or
stoppers. Inert plastic bulbs and caps may be used, but
morphologically distinctive. If these criteria are not met, other
dropping bottles with rubber bulbs are unsatisfactory because
techniques of analysis should be used, such as Practice D 2332
of the effect of some of the immersion liquids on the rubber. It
or Test Methods D 3483, or both.
is essential that the bottles be marked with the refractive index
5.4 Quantitative use of this practice should be limited to
of the contained liquid. Commercially available liquids come
estimates only. For more precise quantitative results, other
in dropping bottles which are acceptable.
methods should be used (see 5.3).
7.13 Refractometer, for measuring the refractive index of
immersion liquids.
6. Interferences
7.14 Sample Vials, 45 by 15-mm.
6.1 Organic material may interfere with both the petro-
7.15 Sieve, No. 100 (149 µm).
graphic and the chemical procedures. Organics can usually be
7.16 Small Alloy Magnet.
removed by solvent extraction as recommended in Practices
D 2331.
8. Reagents
6.2 Deposits containing solid solutions present a complica-
8.1 Purity of Reagents—Reagent grade chemicals shall be
tion in that optical data vary throughout such a system, and
used in all tests. Unless otherwise indicated, it is intended that
unlessthepresenceofthiscomplicationisknown,thedatamay
all reagents shall conform to the specifications of the Commit-
be misinterpreted.
tee onAnalytical Reagents of theAmerican Chemical Society,
6.3 Extremelyfinematerialandopaquematerialaredifficult
where such specifications are available. Other grades may be
to identify. When present in appreciable amounts they may
used, provided it is first ascertained that the reagent is of
cloud over and obscure details of otherwise recognizable
sufficiently high purity to permit its use without lessening the
particles.
accuracy of the determination.
6.4 Interference with the chemical tests will be discussed in
8.1.1 Unless otherwise indicated, references to water shall
the procedures.
be understood to mean reagent water conforming to Specifi-
cation D 1193, Type II.
7. Apparatus
8.2 Ammonium Hydroxide (sp gr 0.90)—Concentrated am-
7.1 Beakers, of borosilicate glass, 30-mL.
monium hydroxide (NH OH).
7.2 Cover Glasses, No. 1 or No. 1 ⁄2 thickness, round or
8.3 AmmoniumMolybdateSolution(100g/L)—Dissolve1g
square cover glasses.
of ammonium molybdate ((NH ) Mo O ·4H O) in water, add
4 6 7 24 2
7.3 Glass Rods,150by5-mm,fortransferringdrops,and75
35 mL of nitric acid HNO (sp gr 1.42) and dilute to 1 L with
by 1-mm, for stirring and leading reagent drops on the slides.
water.
7.4 Hotplate.
8.4 Ammonium Persulfate—((NH ) S O ), crystalline.
4 2 2 8
7.5 Light Source—Microscope lamp with concentrated fila-
8.5 Barium Chloride Solution (100 g/L)—Dissolve 100 g of
ment bulb and a focusing lens.
barium chloride (BaCl ·2H O) in water and dilute to 1 L.
2 2
7.6 Micro Gas Burner.
8.6 Cesium Sulfate—Cs SO crystals, 10 to 20-mesh.
2 4
7.7 Micro Spatula.
8.7 Chloroform.
7.8 Microscope Slides, of selected grade, 25.4 by 76.2-mm
or 25.4 by 50.8-mm (1 by 3-in. or 1 by 2-in.).
7.9 Mortar and Pestle, of tool steel, mullite, or aluminum
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
oxide.
listed by the American Chemical Society, see Analar Standards for Laboratory
7.10 Petrographic Microscope—A microscope equipped
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
with a circular rotating stage, graduated in degrees.The optical
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
system shall include two polarizing devices, one mounted MD.
D 1245–84 (2007)
8.8 Chloroplatinic Acid Solution—Dissolve1gof chloro- 9. Sampling
platinic acid H PtCl ·6H O in 5 mL of water and add 0.5 mL
2 6 2
9.1 Collect the sample in accordance with Practices D 887.
of HCl (sp gr 1.19).
8.9 Diammonium Phosphate Solution (100 g/L)—Dissolve 10. Laboratory Preparation of Samples
100 g of diammonium phosphate (NH ) HPO in water and
4 2 4
10.1 Prepare the sample in accordance with Practices
dilute to 1 L.
D 2331.
8.10 Dimethylglyoxime, crystalline.
10.2 Place a portion of the ground sample (approximately
8.11 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
0.1 g or less) in a porcelain crucible, add four drops of
chloric acid (HCl).
HNO (sp gr 1.42), and evaporate to dryness over the mi-
8.12 HydrochloricAcid (1+4)—MixonevolumeofHCl(sp
croburner.Add 1 mLof water, warm, and stir with a glass rod.
gr 1.19) with four volumes of water.
Allowtheinsolublematerialtosettle.Withdrawportionsofthe
8.13 Lead Acetate Test Paper.
supernatant liquid, henceforth referred to as the test solution,
8.14 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
on the end of a glass rod and transfer to a slide for carrying out
(HNO ).
3 certain of the tests described in Section 11.
8.15 Nitric Acid (1+19)—Mix one volume of HNO (sp gr
1.42) with ten volumes of water. 11. Chemical Procedures
8.16 Phenolphthalein Indicator Solution.
11.1 The tests in this section are intended as an aid to the
8.17 Potassium Ferricyanide [K Fe(CN) ], crystalline.
3 6
petrographic section of this practice. The sensitivity of these
8.18 Potassium Iodide (KI), crystalline.
tests varies so that the operator should become familiar with
8.19 Potassium Mercuric Thiocyanate Solution (100 g/L)—
each test to be able to judge semiquantitatively the amount of
Prepare freshly precipitated mercuric thiocyanate Hg(CNS)
2 each constituent present based on the amount of sample used
by adding a concentrated solution of mercuric nitrate
and the strength of the reaction observed. Some of these tests
Hg(NO ) to a concentrated solution of potassium thiocyanate
3 2 may not be necessary if spectrographic or X-ray diffraction
KCNS.Filterandair-drytheprecipitate.ToonepartHg(CNS)
equipmentorbothareavailable.Foramoredetaileddiscussion
add three parts KCNS, dissolve in a minimum quantity of
of these tests refer to Chamot and Mason (3) or to Feigl (6).
water, and evaporate in a desiccator. Collect the first crop of
11.2 Evolution of Gas with Dilute Acid—Place a portion of
tabular crystals of potassium mercuric thiocyanate
the ground deposit on a slide and allow a drop of HCl (1+4) to
K Hg(CNS) , wash with alcohol, and dry. Dissolve 10 g of the
flow into it. Observe macroscopically or under the 43 objec-
2 4
crystals in water and dilute to 100 mL.
tive for evolution of gas bubbles which indicates that presence
8.20 Refractive Index Standards—A set of liquids having
of carbonates, sulfites, sulfides, nitrites, or metals. Effereve-
refractive indices ranging from 1.40 to 1.74 in steps of 0.01. In
scense due to carbonates is usually violent and of short
the range from 1.45 to 1.65, it is desirable to have liquids
duration.Thegasevolutionduetosulfites,nitrites,andsulfides
available in steps of 0.005. Commercially available liquids are
is usually less vigorous and there is a characteristic odor of the
recommended; however directions for the preparation of suit-
gas. Evolution of hydrogen gas from a metal is usually of
able liquids are given in U. S. Geological Survey Bulletin No.
considerable duration. Dry and examine the slide used for this
848 (1) or Elements of Optical Mineralogy (2). The index of
test. If sodium salts are present, cubic crystals of sodium
refractionoftheseliquidsmustbecheckedpriortotheiruse,as
chloride will be formed. If appreciable amounts of calcium and
they may change from loss of more volatile constituents.
sulfate ions were present, characteristic clumps of
8.21 Silver Nitrate Solution (50 g/L)—Dissolve 50 g of
CaSO ·2H O needles will be formed.
4 2
silvernitrateAgNO inwater,add20mLofHNO (spgr1.42),
11.3 Magnetic Material—Place some of the ground sample
3 3
and dilute to 1 L with water.
on a slide and bring the magnet under the slide.As the magnet
8.22 Sodium Bismuthate—Powdered NaBiO .
moves under the slide, any magnetic material in the sample
8.23 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
will respond to the magnetic field.
(H SO ).
2 4
NOTE 1—Acoating of magnetite on nonmagnetic particles may give an
8.24 Sulfuric Acid (1+19)—Add 1 volume of H SO (sp gr
2 4
erroneous indication of the total amount
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