1、Designation: C 1662 07Standard Practice forFor Measurement of the Glass Dissolution Rate Using theSingle-Pass Flow-Through Test Method1This standard is issued under the fixed designation C 1662; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. 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 single-pass flow-through(SPFT) test method that can be used to meas
3、ure the dissolutionrate of a homogeneous silicate glass, including nuclear wasteglasses, in various test solutions at temperatures less than100C. Tests may be conducted under conditions in which theeffects from dissolved species on the dissolution rate areminimized to measure the forward dissolution
4、 rate at specificvalues of temperature and pH, or to measure the dependence ofthe dissolution rate on the concentrations of various solutespecies.1.2 Tests are conducted by pumping solutions in either acontinuous or pulsed flow mode through a reaction cell thatcontains the test specimen. Tests must
5、be conducted at severalsolution flow rates to evaluate the effect of the flow rate on theglass dissolution rate.1.3 This practice excludes static test methods in which flowis simulated by manually removing solution from the reactioncell and replacing it with fresh solution.1.4 Tests may be conducted
6、 with demineralized water,chemical solutions (such as pH buffer solutions, simulatedgroundwater solutions, and brines), or actual groundwater.1.5 Tests may be conducted with crushed glass of a knownsize fraction or monolithic specimens having known geometricsurface area. The reacted solids may be ex
7、amined to provideadditional information regarding the behavior of the material inthe test and the reaction mechanism.1.6 Tests may be conducted with glasses containing radio-nuclides. However, this test method does not address safetyissues for radioactive samples.1.7 Data from these tests can be use
8、d to determine thevalues of kinetic model parameters needed to calculate theglass corrosion behavior in a disposal system over long periods(for example, see Practice C 1174).1.8 This practice must be performed in accordance with allquality assurance requirements for acceptance of the data.1.9 The va
9、lues stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.10 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
10、 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C92 Test Methods for Sieve Analysis and Water Content ofRefractory MaterialsC 169 Test Methods for Chemical Analysis of Soda-Limeand Borosilicate GlassC 429
11、 Test Method for Sieve Analysis of Raw Materials forGlass ManufactureC 693 Test Method for Density of Glass by BuoyancyC 1109 Practice for Analysis of Aqueous Leachates fromNuclear Waste Materials Using Inductively CoupledPlasma-Atomic Emission SpectroscopyC 1174 Practice for Prediction of the Long-
12、Term Behaviorof Materials, Including Waste Forms, Used in EngineeredBarrier Systems (EBS) for Geological Disposal of High-Level Radioactive WasteC 1220 Test Method for Static Leaching of MonolithicWaste Forms for Disposal of Radioactive WasteC 1285 Test Methods for Determining Chemical Durabilityof
13、Nuclear, Hazardous, and Mixed Waste Glasses andMultiphase Glass Ceramics: The Product Consistency Test(PCT)D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 1293 Test Methods for pH of WaterE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of
14、a Test Method1This practice 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, 2007. Published March 2007 .2For referenced ASTM standards, visit the ASTM websi
15、te, 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 19428-2959, United State
16、s.3. Terminology3.13.1.1 alteration phase, na solid phase formed as a resultof corrosion, including phases precipitated from solution,leached layers, and phases formed within leached layers.3.1.2 back reaction, nreaction between dissolved compo-nents and the glass surface to reform bonds that are br
17、okenduring glass dissolution.3.1.3 chemical durability, nthe resistance of a glass todissolution under particular test conditions.3.1.4 continuous flow, nthe continual replacement ofsolution in the reaction cell with fresh test solution.3.1.5 control test, ntest conducted without specimen tomeasure
18、background concentrations in the test solution andfrom interactions between test solution and apparatus.3.1.6 crushed glass, nsmall particles of glass produced bymechanically fracturing larger pieces of glass.3.1.7 dissolution, nthe result of reactions in which chemi-cal bonds are broken and species
19、 are released from the glassand become dissolved in the test solution.3.1.8 effluent solution, nthe solution exiting the reactioncell.3.1.9 fines, nsmall pieces of glass that adhere to the glassparticles prepared for use in the test that are not removed bysieving.3.1.10 forward glass dissolution rat
20、e, nthe rate at whichglass dissolves into solution at specific values of the tempera-ture and pH in the absence of back reactions.3.1.11 gravimetric, adjmeasured by change in mass.3.1.12 high-purity water, nASTM Type I or Type II waterwith a maximum total matter content including soluble silica of0.
21、1 g/m3and a minimal electrical resistivity of 16.67 MVcmat 25C (see Specification D 1193 and Terminology D 1129).3.1.13 influent solution, nthe solution entering the reac-tion cell.3.1.14 intrinsic rate constant, nthe component of theforward rate constant that depends only on the glass composi-tion3
22、.1.15 leached layer, nresidual material at the glasssurface from which some or all soluble components have beenleached.3.1.16 leaching , nthe preferential loss of soluble compo-nents from a material.3.1.17 mesh size fraction , na designation of the sizerange of crushed glass given by the combination
23、 of the smallestmesh size that the glass is passed through (prefixed by anegative sign) and the largest mesh size that it does not passthrough (prefixed by a positive sign). For example, the 40 +60mesh size fraction will pass through a 40 mesh sieve but willnot pass through a 60 mesh sieve.3.1.18 pu
24、lsed flow, nthe replacement of solution in thereaction cell with fresh test solution due to the regular periodicaction of a mechanical pump. Excludes manual replacement ofthe test solution.3.1.19 reaction cell, nthe container in which the sampleremains during the test.3.1.20 secondary phase, nany ph
25、ase that is not present inthe glass being tested that is formed in solution or on thesurface of the sample or apparatus by combination of compo-nents released from the glass as it dissolved or present in thetest solution.3.1.21 single-pass flow-through test (SPFT), na test inwhich solution is flushe
26、d from the system after contacting thetest specimen and is not recirculated through the reaction cell.3.1.22 steady-state, adjin this standard, the condition inwhich the concentration of a dissolved glass componentremains constant due to the opposing effects of solution flow toremove the components
27、from the vicinity of the sample andglass dissolution to add components to solution. In the presentcontext, dissolution of the glass may proceed at a steady-staterate that is fixed by the solution flow rate, temperature, solutionpH, and other rate-affecting processes.3.1.23 stoichiometric dissolution
28、, nrelease of elementsinto solution in the same proportion that they are in the glass.3.1.24 test solution, nthe solution entering the reactioncell.4. Summary of Practice4.1 Crushed or monolithic glass specimens having a knownsurface area are contacted by a solution that continuously flowsat a known
29、 flow rate and at a constant temperature through areaction cell that contains the glass sample. The concentrationof a soluble glass component (i) in the effluent solution exitingthe sample cell is used to calculate the amount of glass that hasdissolved. The flow rate is determined by dividing the ma
30、ss ofsolution that is collected for analysis by the duration overwhich it was collected. The dissolution rate of the glass iscalculated by using Eq 1:rate 5Cii! Ci#SFSDfi(1)where Ci (i) is the steady-state concentration of componenti measured in the effluent solution, Ci is the backgroundconcentrati
31、on of component i in the influent solution measuredin a blank test, F is the solution flow rate, S is the initialsurface area of the glass sample that is exposed to solution, andfi is the mass fraction of component i in the glass. Severalsamples of the effluent solution are collected during the test
32、 todetermine the steady-state concentrations of dissolved glasscomponents at a particular solution flow rate. Because the glassdissolution rate will likely be affected by the steady-stateconcentrations of dissolved silica and other solutes, tests mustbe conducted at several solution flow rates to pr
33、ovide data thatcan be extrapolated to zero concentration to determine theforward glass dissolution rate at infinite dilutions.5. Significance and Use5.1 This practice provides a prescriptive description of thedesign of a SPFT test apparatus and identifies aspects of theperformance of SPFT tests and
34、interpretation of test results thatmust be addressed by the experimenter to provide confidencein the measured dissolution rate.5.2 The SPFT test method described in this practice can beused to characterize various aspects of glass corrosion behaviorC1662072that can be utilized in a mechanistic model
35、 for calculatinglong-term behavior of a nuclear waste glass.5.3 Depending on the values of test parameters that areused, the results of SPFT tests can be used to measure theintrinsic dissolution rate of a glass, the temperature and pHdependencies of the rate, and the effects of various dissolvedspec
36、ies on the dissolution rate.5.4 The reacted sample recovered from a test may beexamined with surface analytical techniques, such as scanningelectron microscopy, to further characterize the corrosionbehavior. Such examinations may provide evidence regardingwhether the glass is dissolving stoichiometr
37、ically, if particularleached layers and secondary phases were formed on thespecimen surface, and so forth. These occurrences may impactthe accuracy of the glass dissolution rate that is measured usingthis method. This practice does not address the analysis of solidreaction materials.6. Procedure6.1
38、Fig. 1a shows a block diagram for a generic SPFT testassembly. The components of the system include a solutionreservoir, transport lines, a pump, a reaction cell, and acollection bottle. The test solution is pumped from a reservoirthrough a reaction cell that contains the sample by a peristalticFIG.
39、 1 (a) Schematic SPFT Design, (b) Basic Column Reactor Design and (c) Bottle Reactor Design.C1662073pump or similar device. Depending on the temperature ofinterest, the reaction cell may be located in a constant tem-perature oven or water bath. The leachant in the reservoir canbe heated to the test
40、temperature in the same oven. As influentsolution is pumped into the reaction cell, an equal volume ofeffluent solution will be displaced from the reaction cell. Theeffluent solution is sampled several times during the test foranalysis. The mass of effluent that is collected for analysis andthe coll
41、ection time are used to calculate the solution flow ratefor that aliquot. Chemical analysis of the effluent solution isperformed to measure the concentration of the componentsused to calculate the dissolution rate. The concentrations ofseveral glass components can be tracked to determine whetherthe
42、glass is dissolving stoichiometrically. Separate tests areconducted at several flow rates and with several sample surfaceareas to measure the effect of the solution composition (pri-marily the dissolved silica concentration) on the measuredglass dissolution rate.6.2 Either column-type or bottle-type
43、 reaction cells can beused; these are shown schematically in Fig. 1. In the columncell design, the influent solution is pumped (usually upwards)through the crushed glass (or around a monolithic sample). Inthe bottle design, the influent solution is pumped into a cellfilled with solution and displace
44、s an equal volume of effluentsolution. Polyethylene wool or an equivalent material can beused to prevent crushed glass particles from being flushed fromthe reaction cell during the test, or the effluent solution can befiltered after it is collected.6.3 Crushed glass can be used to provide high surfa
45、ce areasamples. Crushed glass is to be prepared following the proce-dure for crushed sample preparation in Test Method C 1285(see Section 19 in C 1285; see also Test Methods C92andC 429 for sieving methods). The surface area of crushed andsieved glass is estimated based on the size fraction that is
46、usedin the test. The particle size of crushed samples must be largeenough that the decrease in surface area during the test is lessthan 15 mass percent. The initial surface area can be calculatedfrom the specific surface area and using the arithmetic averageof the sizes of the sieve mesh and the den
47、sity of the glass (seeAppendix X1 in C 1285). The final surface area can becalculated based on the amount of glass that dissolved duringthe test, if the particles can be modeled to have geometricshapes. The crushed glass used in a series of SPFT tests mustbe from the same source to represent the hom
48、ogeneity of theglass on the scale of the test sample size. (A series of SPFTtests refers to tests conducted with the same glass and testsolution but with different masses of glass or at different flowrates.) It is recommended that a small amount of the crushedglass be examined with a scanning electr
49、on microscope prior totesting to document the size of the particles and the absence offines.6.4 Monolithic samples can be used to provide samples withlow surface areas. Samples can be prepared with any shape forwhich the geometric surface area can be measured directly.Monolithic samples are to be prepared following the samplepreparation procedure in Test Method C 1220 (see Section 8 inC 1220). Enough monolithic glass samples shall be preparedfor use in a series of SPFT tests. The surface finishes of themonoliths to be used in the series of tests sha
