1、Designation: D 1245 08Standard Practice forExamination of Water-Formed Deposits by ChemicalMicroscopy1This standard is issued under the fixed designation D 1245; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes a procedure for the examinationof water-formed deposits by means of chemical microscopy.This practice
3、may be used to complement other methods ofexamination of water-formed deposits as recommended inPractices D 2331 or it may be used alone when no otherinstrumentation is available or when the sample size is verysmall.1.2 The values stated in SI units are to be regarded asstandard. No other units of m
4、easurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory
5、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 887 Practices for Sampling Water-Formed DepositsD 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD 2332 Practice for Analysis
6、 of Water-Formed Deposits byWavelength-Dispersive X-Ray FluorescenceD 3483 Test Methods for Accumulated Deposition in aSteam Generator Tube3. Terminology3.1 DefinitionsFor definitions of terms in this practicerelating specifically to water and water-formed deposits, referto Terminology D 1129.3.2 De
7、scriptions of Terms Specific to This StandardCertain terms in this practice that relate specifically to chemicalmicroscopy are described as follows:3.2.1 anisotropichaving different optical properties indifferent optical planes. These planes are referred to as thealpha, beta, and omega axes.3.2.2 Be
8、cke linea faint, halo-like line that surrounds acrystal when the crystal is mounted in an oil of differentrefractive index. It increases in intensity as the difference in therefractive index between the crystal and the oil increases.3.2.3 dispersionthe variation of index of refraction withwavelength
9、.3.2.4 dispersion stainingthe color effects produced whena transparent object, immersed in a liquid having a refractiveindex near that of the object is viewed under the microscope bytransmitted white light and precise aperture control.3.2.5 extinction anglethe angle between the extinctionposition an
10、d some plane, edge, or line in a crystal.3.2.6 extinction positionthe position in which an aniso-tropic crystal, between crossed polars, exhibits complete dark-ness.3.2.7 index of refractionthe numerical expression of theratio of the velocity of light in a vacuum to the velocity of lightin a substan
11、ce.3.2.8 isotropichaving the same optical properties in alldirections.3.2.9 petrographicpertaining to the description of rocksor rocklike substances. Such description is usually in terms ofmorphology and optical properties.3.2.10 solid solutiona homogeneous mixture of two ormore components, in the s
12、olid state, retaining substantially thestructure of one of the components.4. Summary of Practice4.1 The practice is essentially chemical microscopical,supplemented by optical data obtained by the petrographicmethod. The identification of compounds is made by observ-ing, under the microscope, charact
13、eristic reactions and precipi-tates resulting from the action of specific reagents on the solidsample or solutions thereof, and by measuring the opticalproperties.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.03 on Samplin
14、g Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved May 1, 2008. Published May 2008. Originallyapproved in 1952. Last previous edition approved in 2007 as D 1245 84 (2007).2For referenced
15、ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
16、ohocken, PA 19428-2959, United States.5. Significance and Use5.1 Chemical composition of water-formed deposits is amajor indicator of proper or improper chemical treatment ofprocess water, and is often an indicator of operational param-eters as well, for example, temperature control. This practiceal
17、lows for rapid determination of constituents present in thesedeposits, particularly those indications of improper watertreatment, since they usually have very distinctive and easilyrecognized optical properties.5.2 This practice, where applicable, eliminates the need fordetailed chemical analysis, w
18、hich is time-consuming, andwhich does not always reveal how cations and anions aremutually bound.5.3 Qualitative use of this practice should be limited tothose deposits whose control is generally known or predictable,based on treatment and feedwater mineral content, and whoseconstituents are crystal
19、line, or in other ways optically ormorphologically distinctive. If these criteria are not met, othertechniques of analysis should be used, such as Practice D 2332or Test Methods D 3483, or both.5.4 Quantitative use of this practice should be limited toestimates only. For more precise quantitative re
20、sults, othermethods should be used (see 5.3).6. Interferences6.1 Organic material may interfere with both the petro-graphic and the chemical procedures. Organics can usually beremoved by solvent extraction as recommended in PracticesD 2331.6.2 Deposits containing solid solutions present a complica-t
21、ion in that optical data vary throughout such a system, andunless the presence of this complication is known, the data maybe misinterpreted.6.3 Extremely fine material and opaque material are difficultto identify. When present in appreciable amounts they maycloud over and obscure details of otherwis
22、e recognizableparticles.6.4 Interference with the chemical tests will be discussed inthe procedures.7. Apparatus7.1 Beakers, of borosilicate glass, 30-mL.7.2 Cover Glasses, No. 1 or No. 112 thickness, round orsquare cover glasses.7.3 Glass Rods, 150 by 5-mm, for transferring drops, and 75by 1-mm, fo
23、r stirring and leading reagent drops on the slides.7.4 Hotplate.7.5 Light SourceMicroscope lamp with concentrated fila-ment bulb and a focusing lens.7.6 Micro Gas Burner.7.7 Micro Spatula.7.8 Microscope Slides, of selected grade, 25.4 by 76.2-mmor 25.4 by 50.8-mm.7.9 Mortar and Pestle, of tool steel
24、, mullite, or aluminumoxide.7.10 Petrographic MicroscopeA microscope equippedwith a circular rotating stage, graduated in degrees. The opticalsystem shall include two polarizing devices, one mountedbelow the condenser and the other just above the objective;43,103, and 453 objectives; and 53 and 103
25、eyepiecesfitted with crosshairs. The optic axis of the microscope shall beadjustable so that it can be brought into coincidence with thecenter of rotation of the revolving stage.ABertrand-Amici lensequipped with an iris diaphragm, or a sliding stop ocular, shallbe used for viewing interference figur
26、es. A quartz wedge,gypsum plate, and standard mica plate are necessary externalaccessories. Aperture stops are necessary for observing thecolor effects of dispersion, that is, dispersion staining. Acardboard “washer” in the objective and a cover glass with acentered dried drop of India ink are suffi
27、cient; however, adevice is available commercially.7.11 Porcelain Crucibles, No. 0.7.12 Reagent Bottles for Immersion LiquidsGlass drop-ping bottles of 30-mL capacity. These bottles shall be equippedwith groundglass stoppers with dropping rods integral with thestoppers. Inert plastic bulbs and caps m
28、ay be used, butdropping bottles with rubber bulbs are unsatisfactory becauseof the effect of some of the immersion liquids on the rubber. Itis essential that the bottles be marked with the refractive indexof the contained liquid. Commercially available liquids comein dropping bottles which are accep
29、table.7.13 Refractometer, for measuring the refractive index ofimmersion liquids.7.14 Sample Vials, 45 by 15-mm.7.15 Sieve, No. 100 (149 m).7.16 Small Alloy Magnet.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall r
30、eagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening
31、theaccuracy of the determination.8.1.1 References to water shall be understood to mean waterthat meets or exceeds the quantitative specifications for type Ior II reagent water conforming to Specification D 1193, Sec-tion 1.1.8.2 Ammonium Hydroxide (sp gr 0.90)Concentrated am-monium hydroxide (NH4OH)
32、.8.3 Ammonium Molybdate Solution (100 g/L)Dissolve 1 gof ammonium molybdate (NH4)6Mo7O244H2O) in water, add35 mL of nitric acid HNO3(sp gr 1.42) and dilute to 1 L withwater.8.4 Ammonium Persulfate(NH4)2S2O8), crystalline.8.5 Barium Chloride Solution (100 g/L)Dissolve 100 g ofbarium chloride (BaCl22H
33、2O) in water and dilute to 1 L.8.6 Cesium SulfateCs2SO4crystals, 10 to 20-mesh.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for Labor
34、atoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D12450828.7 Chloroform.8.8 Chloroplatinic Acid SolutionDissolve1gofchloro-platinic acid H2PtCl66H2O in 5 mL of water and add 0.5 mLof HCl
35、(sp gr 1.19).8.9 Diammonium Phosphate Solution (100 g/L)Dissolve100 g of diammonium phosphate (NH4)2HPO4in water anddilute to 1 L.8.10 Dimethylglyoxime, crystalline.8.11 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).8.12 Hydrochloric Acid (1+4)Mix one volume of HCl (spgr 1.19)
36、with four volumes of water.8.13 Lead Acetate Test Paper.8.14 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).8.15 Nitric Acid (1+19)Mix one volume of HNO3(sp gr1.42) with ten volumes of water.8.16 Phenolphthalein Indicator Solution.8.17 Potassium Ferricyanide K3Fe(CN)6, crystalline.8.18 Potas
37、sium Iodide (KI), crystalline.8.19 Potassium Mercuric Thiocyanate Solution (100 g/L)Prepare freshly precipitated mercuric thiocyanate Hg(CNS)2by adding a concentrated solution of mercuric nitrateHg(NO3)2to a concentrated solution of potassium thiocyanateKCNS. Filter and air-dry the precipitate. To o
38、ne part Hg(CNS)2add three parts KCNS, dissolve in a minimum quantity ofwater, and evaporate in a desiccator. Collect the first crop oftabular crystals of potassium mercuric thiocyanateK2Hg(CNS)4, wash with alcohol, and dry. Dissolve 10 g of thecrystals in water and dilute to 100 mL.8.20 Refractive I
39、ndex StandardsA set of liquids havingrefractive indices ranging from 1.40 to 1.74 in steps of 0.01. Inthe range from 1.45 to 1.65, it is desirable to have liquidsavailable in steps of 0.005. Commercially available liquids arerecommended; however directions for the preparation of suit-able liquids ar
40、e given in U. S. Geological Survey Bulletin No.848 (1)4or Elements of Optical Mineralogy (2). The index ofrefraction of these liquids must be checked prior to their use, asthey may change from loss of more volatile constituents.8.21 Silver Nitrate Solution (50 g/L)Dissolve 50 g ofsilver nitrateAgNO3
41、in water, add 20 mLof HNO3(sp gr 1.42),and dilute to 1 L with water.8.22 Sodium BismuthatePowdered NaBiO3.8.23 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).8.24 Sulfuric Acid (1+19)Add 1 volume of H2SO4(sp gr1.84) slowly and with stirring to 19 volumes of water.8.25 Zinc DustPowdered
42、zinc metal.8.26 Zinc Uranyl Acetate SolutionDissolve1gofuranylacetate UO2(C2H3O2)22H2O and 0.1 mL of glacial acetic acidin 5 mL of water. Dissolve3gofzinc acetateZn(C2H3O2)22H2O and 0.1 mL of glacial acetic acid in 5 mLof water. Warm if necessary to complete solution. Mix the twosolutions and store
43、in a chemically resistant glass bottle. Ifprecipitation occurs, filter the solution before use.9. Sampling9.1 Collect the sample in accordance with Practices D 887.10. Laboratory Preparation of Samples10.1 Prepare the sample in accordance with PracticesD 2331.10.2 Place a portion of the ground sampl
44、e (approximately0.1 g or less) in a porcelain crucible, add four drops ofHNO3(sp gr 1.42), and evaporate to dryness over the mi-croburner. Add 1 mL of water, warm, and stir with a glass rod.Allow the insoluble material to settle. Withdraw portions of thesupernatant liquid, henceforth referred to as
45、the test solution,on the end of a glass rod and transfer to a slide for carrying outcertain of the tests described in Section 11.11. Chemical Procedures11.1 The tests in this section are intended as an aid to thepetrographic section of this practice. The sensitivity of thesetests varies so that the
46、operator should become familiar witheach test to be able to judge semiquantitatively the amount ofeach constituent present based on the amount of sample usedand the strength of the reaction observed. Some of these testsmay not be necessary if spectrographic or X-ray diffractionequipment or both are
47、available. For a more detailed discussionof these tests refer to Chamot and Mason (3) or to Feigl (6).11.2 Evolution of Gas with Dilute AcidPlace a portion ofthe ground deposit on a slide and allow a drop of HCl (1+4) toflow into it. Observe macroscopically or under the 43 objec-tive for evolution o
48、f gas bubbles which indicates that presenceof carbonates, sulfites, sulfides, nitrites, or metals. Effereve-scense due to carbonates is usually violent and of shortduration. The gas evolution due to sulfites, nitrites, and sulfidesis usually less vigorous and there is a characteristic odor of thegas
49、. Evolution of hydrogen gas from a metal is usually ofconsiderable duration. Dry and examine the slide used for thistest. If sodium salts are present, cubic crystals of sodiumchloride will be formed. If appreciable amounts of calcium andsulfate ions were present, characteristic clumps ofCaSO42H2O needles will be formed.11.3 Magnetic MaterialPlace some of the ground sampleon a slide and bring the magnet under the slide. As the magnetmoves under the slide, any magnetic material in the samplewill respond to the magnetic field.NOTE 1A coat
