1、Designation: C1720 11Standard Test Method forDetermining Liquidus Temperature of Immobilized WasteGlasses and Simulated Waste Glasses1This standard is issued under the fixed designation C1720; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These practices cover procedures for determining theliquidus temperature (TL) of nuclear waste,
3、mixed nuclearwaste, simulated nuclear waste, or hazardous waste glass in thetemperature range from 600C to 1600C. This method differsfrom Practice C829 in that it employs additional methods todetermine TL. TLis useful in waste glass plant operation, glassformulation, and melter design to determine t
4、he minimumtemperature that must be maintained in a waste glass melt tomake sure that crystallization does not occur or is below aparticular constraint, for example, 1 volume % crystallinity orT1%. As of now, many institutions studying waste and simu-lated waste vitrification are not in agreement reg
5、arding thisconstraint (1).1.2 Three methods are included, differing in (1) the type ofequipment available to the analyst (that is, type of furnace andcharacterization equipment), (2) the quantity of glass availableto the analyst, (3) the precision and accuracy desired for themeasurement, and (4) can
6、didate glass properties. The glassproperties, for example, glass volatility and estimated TL, willdictate the required method for making the most precisemeasurement. The three different approaches to measuring TLdescribed here include the following: (A) Gradient Tempera-ture Furnace Method (GT),(B)
7、Uniform Temperature FurnaceMethod (UT), and (C) Crystal Fraction Extrapolation Method(CF). This procedure is intended to provide specific workprocesses, but may be supplemented by test instructions asdeemed appropriate by the project manager or principle inves-tigator. The methods defined here are n
8、ot applicable to glassesthat form multiple immiscible liquid phases. Immiscibility maybe detected in the initial examination of glass during samplepreparation (see 9.3). However, immiscibility may not becomeapparent until after testing is underway.1.3 The values stated in either SI units or inch-pou
9、nd unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to a
10、ddress 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C162 Termin
11、ology of Glass and Glass ProductsC829 Practices for Measurement of Liquidus Temperatureof Glass by the Gradient Furnace MethodD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting
12、an Interlaboratory Study toDetermine the Precision of a Test MethodE2282 Guide for Defining the Test Result of a Test Method2.2 Other Documents:SRM-773 National Institute for Standards and Technology(NIST) Liquidus Temperature StandardSRM-674b NIST X-Ray Powder Diffraction Intensity Setfor Quantitat
13、ive Analysis by X-Ray Diffraction (XRD)SRM-1976a NIST Instrument Response Standard for X-RayPowder DiffractionZ540.3 American National Standards Institute/NationalConference of Standards Laboratories (ANSI/NCSL) Re-quirements for the Calibration of Measuring and TestEquipment3. Terminology3.1 Defini
14、tions:1This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.13 on Spent Fueland High Level Waste.Current edition approved Feb. 1, 2011. Published April 2011. DOI: 10.1520/C172011.2For referenced ASTM standards, vis
15、it 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 Conshohocken, PA 19428-2
16、959, United States.3.1.1 air quenchingto pour or place a molten glassspecimen on a surface, for example, a steel plate, and cool it tothe solid state.3.1.2 annealto prevent or remove materials processingstresses in glass by controlled cooling from a suitable tempera-ture, for example, the glass tran
17、sition temperature (Tg) (modi-fied from Terminology C162).3.1.3 annealinga controlled cooling process for glassdesigned to reduce thermal residual stress to an acceptablelevel and, in some cases, modify structure (modified fromTerminology C162).3.1.4 ASTM Type I waterpurified water with a maximumtot
18、al matter content including soluble silica of 0.1 g/m3,amaximum electrical conductivity of 0.056 V/cm at 25C anda minimum electrical resistivity of 18 MV3cm at 25C (seeSpecification D1193 and Terminology D1129).3.1.5 cleaning glassglass or flux used to remove highviscosity glass, melt insolubles, or
19、 other contamination fromplatinum-ware.3.1.6 crystallizeto form or grow, or both, crystals from aglass melt during heat-treatment or cooling.3.1.7 crystallizationthe progression in which crystals arefirst nucleated and then grown within a host medium. Gener-ally, the host may be a gas, liquid, or an
20、other crystalline form.However, in this context, it is assumed that the medium is aglass melt.3.1.8 crystallization frontthe boundary between the crys-talline and crystal-free regions in a test specimen that wassubjected to a temperature gradient heat-treatment.3.1.9 furnace profilingthe process of
21、determining theactual temperature inside of a furnace at a given location; thisinvolves different processes for different types of furnaces.3.1.10 glassan inorganic product of fusion that has cooledto a rigid condition without crystallizing (see TerminologyC162); a noncrystalline solid or an amorpho
22、us solid (2).33.1.11 glass ceramicsolid material, partly crystalline andpartly glassy (see Terminology C162).3.1.12 glass samplethe material to be heat-treated ortested by other means.3.1.13 glass specimenthe material resulting from a spe-cific heat treatment.3.1.14 glass transition temperature (Tg)
23、on heating, thetemperature at which a glass transforms from a solid to a liquidmaterial, characterized by the onset of a rapid change in severalproperties, such as thermal expansivity.3.1.15 gradient furnacea furnace in which a knowntemperature gradient is maintained between the two ends.3.1.16 haza
24、rdous waste glassa glass composed of glassforming additives and hazardous waste.3.1.17 homogeneous glassa glass that is a single amor-phous phase; a glass that is not separated into multipleamorphous phases.3.1.18 inhomogeneous glassa glass that is not a singleamorphous phase; a glass that is either
25、 phase separated intomultiple amorphous phases or is crystallized.3.1.19 liquidus temperaturethe maximum temperature atwhich equilibrium exists between the molten glass and itsprimary crystalline phase.3.1.20 melt insolublea crystalline, amorphous, or mixedphase material that is not appreciably solu
26、ble in molten glass,for example, noble metals, noble metal oxides.3.1.21 mixed wastewaste containing both radioactive andhazardous components regulated by the Atomic Energy Act(AEA) (3) and the Resource Conservation and Recovery Act(RCRA) (4), respectively; the term “radioactive component”refers to
27、the actual radionuclides dispersed or suspended in thewaste substance (5).3.1.22 molda pattern, hollow form, or matrix for giving acertain shape or form to something in a plastic or molten state.Websters43.1.23 nuclear waste glassa glass composed of glass-forming additives and radioactive waste.3.1.
28、24 observationthe process of obtaining informationregarding the presence or absence of an attribute of a testspecimen or of making a reading on a characteristic ordimension of a test specimen (see Terminology E2282).3.1.25 phase separated glassa glass containing more thanone amorphous phase.3.1.26 p
29、referred orientationwhen there is a stronger ten-dency for the crystallites in a powder or a texture to be orientedmore one way, or one set of ways, than all others. This istypically due to the crystal structure. IUCr53.1.27 primary phasethe crystalline phase at equilibriumwith a glass melt at its l
30、iquidus temperature.3.1.28 radioactiveof or exhibiting radioactivity; a mate-rial giving or capable of giving off radiant energy in the formof particles or rays, for example, a, b, and g,bythedisintegration of atomic nuclei; said of certain elements, suchas radium, thorium, and uranium and their pro
31、ducts.American Heritage6Websters73.1.29 Round-Robinan interlaboratory and intralabora-tory testing process to develop the precision and bias of aprocedure.3.1.30 sectiona part separated or removed by cutting; aslice, for example, representative thin section of the glassspecimen. Websters43.1.31 set
32、of samplessamples tested simultaneously in thesame oven.3.1.32 simulated nuclear waste glassa glass composed ofglass forming additives with simulants of, or actual chemicalspecies, or both, in radioactive wastes or in mixed nuclearwastes, or both.3.1.33 standardto have the quality of a model, gage,p
33、attern, or type. Websters73.1.34 standardizeto make, cause, adjust, or adapt to fit astandard (5); to cause to conform to a given standard, forexample, to make standard or uniform. Websters73The boldface numbers in parentheses refer to a list of references at the end ofthis standard.4Websters New Un
34、iversal Unabridged Dictionary, 1979.5IUCr Online Dictionary of Crystallography, 2011.6American Heritage Dictionary, 1973.7Websters New Twentieth Century Dictionary, 1973.C1720 1123.1.35 surface tensiona property, due to molecular forces,by which the surface film of all liquids tends to bring thecont
35、ained volume into a form having the least possible area.3.1.36 test determinationthe value of a characteristic ordimension of a single test specimen derived from one or moreobserved values (see Terminology E2282).3.1.37 test methoda definitive procedure that produces atest result (see Terminology E2
36、282).3.1.38 test observationsee observation.3.1.39 test resultthe value of a characteristic obtained bycarrying out a specific test method (see Terminology E2282).3.1.40 uniform temperature furnacea furnace in whichthe temperature is invariant over some defined volume andwithin some defined variance
37、.3.1.41 vitrificationthe process of fusing waste with glassmaking chemicals at elevated temperatures to form a wasteglass (see Terminology C162).3.1.42 volatilitythe act of one or more constituents of asolid or liquid mixture to pass into the vapor state.3.1.43 waste glassa glass developed or used f
38、or immobi-lizing radioactive, mixed, or hazardous wastes.3.2 Abbreviations:3.2.1 AEAAtomic Energy Act3.2.2 ANSIAmerican National Standards Institute3.2.3 ASTMAmerican Society for Testing and Materials3.2.4 CFcrystal fraction extrapolation3.2.5 CFcrystal fraction in a sample or specimen3.2.6 EDSenerg
39、y dispersive spectrometry3.2.7 hviscosity3.2.8 FWHMfull width of a peak at half maximum3.2.9 GFgradient temperature furnace3.2.10 GTgradient temperature3.2.11 HFhydrofluoric acid3.2.12 HLWhigh-level waste3.2.13 IDidentification3.2.14 NBSNational Bureau of Standards3.2.15 NCSLNational Conference of S
40、tandards Laborato-ries3.2.16 NISTNational Institute for Standards and Technol-ogy (formerly NBS)3.2.17 OMoptical microscope or optical microscopy3.2.18 PDFpowder diffraction file3.2.19 RCRAResource Conservation and Recovery Act3.2.20 RIRrelative intensity ratio3.2.21 RLMreflected light microscopy3.2
41、.22 SEMscanning electron microscope or scanningelectron microscopy3.2.23 SRMStandard Reference Material3.2.24 T1%temperature where glass contains 1 volume %of a crystalline phase3.2.25 Taprimary UT measurement above TL3.2.26 Tcprimary UT measurement below TL3.2.27 Tgglass transition temperature3.2.2
42、8 TLliquidus temperature3.2.29 TLMtransmitted light microscopy3.2.30 TMmelting temperature for glass preparations3.2.31 UFuniform temperature furnace3.2.32 UTuniform temperature3.2.33 WCtungsten carbide3.2.34 XRDX-ray diffraction4. Summary of Test Method4.1 This procedure describes methods for deter
43、mining theTLof waste or simulated waste glasses. Temperature is definedas the maximum temperature at which equilibrium existsbetween the molten glass and its primary crystalline phase. Inother words, TLis the maximum temperature at which a glassmelt crystallizes. Fig. 1 illustrates an example TLfor
44、a simpletwo-component liquid on a binary phase diagram.4.1.1 (A) Gradient Temperature Furnace Method (GT)This method is similar to Practice C829, “Standard Practicesfor Measurement of Liquidus Temperature of Glass by theFIG. 1 Binary Phase Diagram of Components A and B with TLof Composition C Highli
45、ghtedC1720 113Gradient Furnace Method,” though it has been modified tomeet the specific needs of waste and simulated waste glassmeasurements. The most pronounced differences between thismethod and the Practice C829 “boat method” are the samplepreparation and examination procedures.4.1.1.1 Samples ar
46、e loaded into a boat, for example, plati-num alloy (Fig. 2) with a tight-fitting lid, and exposed to alinear temperature gradient in a gradient furnace (Fig. 3) for afixed period of time. The temperature, as a function of distance,d, along the sample, is determined by its location within theGF, and
47、the TLis then related to the location of the crystalli-zation front in the heat-treated specimen (Fig. 4).4.1.1.2 Following the heat-treatment, the specimen shouldbe annealed at or near the glass transition, Tg, of the glass (thisshould be previously measured or estimated) to reduce speci-men cracki
48、ng during cutting and polishing.4.1.1.3 The specimen should then be scored or marked tosignify the locations on the specimen located at different depthsinto the gradient furnace, that is, locations heat-treated atspecific temperatures.4.1.1.4 If the specimen is optically transparent, it can beobserv
49、ed with transmitted light (that is, transmitted lightmicroscopy or TLM) or reflected light microscopy (RLM) tolook for bulk or surface crystallization, respectively. If thespecimen is not optically transparent or is barely opticallytransparent (for example, in high iron glasses with highquantities of FeO), a cut or fractured section of the glass can bepolished very thin (that is, a thin section can be made) to allowfor observation. Another option for surface observations isscanning electron mi
