1、Designation: C871 08a1Standard Test Methods forChemical Analysis of Thermal Insulation Materials forLeachable Chloride, Fluoride, Silicate, and Sodium Ions1This standard is issued under the fixed designation C871; the number immediately following the designation indicates the year oforiginal adoptio
2、n or, in the case of 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.1NOTEFootnote 10 was editorially corrected in February 2011.1. Scope1.1 These test meth
3、ods cover laboratory procedures for thedetermination of water-leachable chloride, fluoride, silicate,and sodium ions in thermal insulation materials in the parts permillion range.1.2 Selection of one of the test methods listed for each of theionic determinations required shall be made on the basis o
4、flaboratory capability and availability of the required equipmentand appropriateness to the concentration of the ion in theextraction solution.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are pro
5、vided for information onlyand are not considered standard.1.4 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-bil
6、ity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C168 Terminology Relating to Thermal InsulationC692 Test Method for Evaluating the Influence of ThermalInsulations on External Stress Corrosion Cracking Ten-dency of Austenitic Stainless SteelC795 Specification for
7、 Thermal Insulation for Use in Con-tact with Austenitic Stainless SteelC871 Test Methods for Chemical Analysis of ThermalInsulation Materials for Leachable Chloride, Fluoride,Silicate, and Sodium IonsD1428 Test Method for Sodium and Potassium in Water andWater-Formed Deposits by Flame Photometry32.2
8、 AWWA Standards:4500-Si D Molybdosilicate Method for Silica44500-Si E Heteropoly Blue Method for Silica43. Terminology3.1 DefinitionsRefer to Terminology C168 for definitionsrelating to insulation.4. Summary of Test Methods4.1 Insulation specimens are leached for 30 min in boilingwater. Tests to det
9、ermine quantitatively chloride, fluoride,silicate, and sodium ions are performed on aliquots of thefiltered leachate solution.4.2 Analysis for Chloride:4.2.1 Amperometric-coulometric titration test method.4.2.2 Titrimetric test method. This method is no longerrecommended as requested by ASTM Interna
10、tional due to useof a specific hazardous substance.4.2.3 Specific ion electrode test method.4.3 Analysis for Fluoride:4.3.1 Specific ion electrode test method.4.3.2 SPADNS colorimetric test method.4.4 Analysis for Silicate:4.4.1 Atomic absorption spectrophotometry test method.4.4.2 Colorimetric test
11、 methodsAWWA Methods 4500-SiD and 4500-Si E.4.5 Analysis for Sodium:4.5.1 Flame photometric test methodTest Methods D1428.4.5.2 Atomic absorption spectrophotometry test method.4.5.3 Sodium Ion-Selective electrode.5. Significance and Use5.1 Research has demonstrated that in addition to the halideion
12、chloride; fluoride ions, when deposited and concentrated on1These test methods are under the jurisdiction of ASTM Committee C16 onThermal Insulation and are the direct responsibility of Subcommittee C16.31 onChemical and Physical Properties.Current edition approved Feb. 17, 2011. Published January 2
13、009. Originallyapproved in 1977. Last previous edition approved in 2008 as C871 08. DOI:10.1520/C0871-08A.2For referenced 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 standa
14、rds Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Standard Methods for the Examination of Water and Wastewater, 17thEdition, American Public Health Association, Washington, DC, 1989.1Copyright ASTM Internation
15、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the surface of austenitic stainless steel, can contribute toexternal stress corrosion cracking (ESCC) in the absence ofinhibiting ions.5Two widely used insulation specifications thatare specific to ESCC allow the
16、 use of the same Test MethodsC692 and C871 for evaluation of insulation materials. Bothspecifications require fluoride ions to be included with chlorideions when evaluating the extractable ions.5.2 Chlorides (and fluorides) can be constituents of theinsulating material or of the environment, or both
17、. Moisture inthe insulation or from the environment can cause chlorides(and fluorides) to migrate through the insulation and concen-trate at the hot stainless steel surface.5.3 The presence of sodium and silicate ions in the insula-tion has been found to inhibit external stress corrosion crackingcau
18、sed by chloride (and fluoride) ions, whether such ions comefrom the insulation itself or from external sources. Further-more, if the ratio of sodium and silicate ions to chloride (andfluoride) ions is in a certain proportion in the insulation,external stress corrosion cracking as a result of the pre
19、sence ofchloride (and fluoride) in the insulation will be prevented or atleast mitigated (see also Specification C795).6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications o
20、f the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.6Use other grades onlyif is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of thedetermination.6.2 Purity of WaterDistil
21、led or deionized water (DI),having maximum conductivity of 2.5 S/cm and containingless than 0.1 ppm of chloride ions shall be used in all tests.7. Sampling7.1 With low-chloride insulating materials, wear clean poly-ethylene gloves while taking and handling the sample to avoidchloride contamination f
22、rom perspiration. Do not use glovesmade from chloride-containing compounds such as neopreneor saran, or materials with metallic chlorides in their formula-tions. Prior to use, rinse gloves twice, drain, and air-dry in aclean, halide-free environment. Store clean gloves in a closedcontainer or envelo
23、pe.7.2 It is suitable to handle materials with more than 25 ppmchloride with clean, dry hands with no significant contamina-tion.8. Test Specimen8.1 Apparatus and tools used for special preparation andleaching shall be clean and free of chlorides, fluorides, sili-cates, sodium, and acidic or alkalin
24、e materials that might affectthe chemical test. Distilled water must be used in all testsunless deionized water has been shown to be adequate.8.1.1 For molded insulation, use a band saw or equivalent,making several cuts through the entire cross section of eachpiece of insulation to be tested. Each s
25、pecimen shall berepresentative of the entire cross section of the piece, exceptthat metal screen, or expanded metal used as a supportivefacing shall not be included. It is recommended that thin wafersof material be cut between116 and18 in. (1.6 and 3.2 mm)thick. Cut enough material for two 20-g samp
26、les.8.1.2 Blanket fibrous materials are cut into strips across theentire width of the blanket using clean, dry scissors.8.1.3 Samples containing moisture are placed in a suitablecontainer, protected from contamination, and oven dried at 2306 10F (100 6 5C) ( or manufacturers recommendedtemperature)
27、to a constant weight (60.1 g) or overnight.9. Extraction Technique9.1 Apparatus:9.1.1 Electronic Balance, capable of weighing to 2000 gwith readability to the nearest 0.1 g.9.1.2 Blender, with jar-top thread preferred.9.1.3 Beaker, 1-L stainless or borosilicate.9.1.4 Filter, Buchner with suitable fi
28、lter paper.9.2 Using a closed-top blender, such as a 1-qt Mason jarwith blender blades, blend exactly 20.0 g of sample (or otherweight if necessary) in approximately 400 mLof DI or distilledwater for 30 s. While most materials blend to a homogeneousmixture in 30 s, some very hard materials require 6
29、0 s or more.9.3 Quantitatively transfer the mixture to a tared 1-L stain-less steel or borosilicate beaker, rinsing with distilled or DIwater.9.4 Bring to boiling and maintain at the boiling point for 306 5 min.9.5 Remove from heat, and cool in a cold water bath toambient temperature.9.6 Remove wate
30、r from the outside of the beaker and placeon a balance. Add DI (or distilled) water to bring amount ofwater up to exactly 500.0 mL(g) (or other weight if necessary).9.7 Stir mixture until it is uniform and filter through filterpaper to get a clear filtrate. If not clear after the first filtration,re
31、filter through a finer filter paper. The first small portion offiltrate is used to rinse the receiving flask and SolutionAbottle.Complete this filtration by putting this filtrate in the bottlelabeled Solution A. Since the relationship between solids andliquid has been established, it is not necessar
32、y to filter all of theextract. DO NOT WASH THE FILTER CAKE!9.8 Calculate the Gravimetric Conversion Factor (GCF) bydividing the weight of the water by the weight of the sample.In the ideal case, this is 500/20 = 25. If weights are not exactlyas prescribed, a correct GCF must be calculated and used.9
33、.9 With calcium silicate insulation it has been shown that itis not necessary to pulverize the thin chips called for in 8.1.1.5Whorlow, Kenneth M., Woolridge, Edward and Hutto, Francis B., Jr., “ Effectof Halogens and Inhibitors on the External Stress Corrosion Cracking of Type 304Austenitic Stainle
34、ss Steel”; STP 1320 Insulation Materials: Testing and Applica-tions, Third Volume, Ronald S. Graves and Robert R. Zarr, editors, ASTM WestConshohocken, PA, 1997, page 485.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the te
35、sting of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary , U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.C871 08a12Equivalent results are obtained, a
36、nd a lengthy filtration step isavoided, by extracting the unpulverized chips.10. Test Procedures10.1 Chloride DeterminationOne of the following testmethods shall be used on a fresh aliquot from Solution A. Theprecision of the test equipment is often improved through theuse of analytical techniques i
37、nvolving known addition (orsample and standard spiking) when the ion concentrations arevery low. It is recommended for chloride ion concentrationsless than 20 ppm.10.1.1 Amperometric-Coulometric Titration Test MethodUse an apparatus7in which direct current between a pair ofsilver electrodes causes e
38、lectrochemical oxidation of the anodeand produces silver ions at a constant rate. When all of thechloride ions have combined with silver ions, the appearanceof free silver ions causes an abrupt increase in current betweena pair of indicator electrodes. Because silver ions are generatedat a constant
39、rate, the amount used to precipitate the chlorideions is proportional to the elapsed time. Hence, the chloridecontent of the titration solution can be determined. Since thecoulometric titrator would not discriminate between chloride,bromide, and iodideall would test as chloridein somecases it is pra
40、ctical to differentiate between the halides to showchloride only, since the others have not been shown to causestress corrosion cracking in austenitic stainless steel. Achloride-sensitive electrode detects chloride only.10.1.2 Titrimetric Test Method8This method is no longerrecommended as requested
41、by ASTM International due to useof specific hazardous substance.10.1.3 Specific Ion Electrode Test MethodThe chloride-sensitive electrode consists of silver halide/silver sulfide mem-branes bonded into the tip of an epoxy electrode body. Whenthe membrane is in contact with a chloride solution, silve
42、r ionsdissolve from the membrane surface and the electrode developsa potential due to the silver ion concentration. This concentra-tion is in turn determined by the sample chloride ion concen-tration. This potential is measured against a constant referencepotential with a digital pH/mV meter or spec
43、ific ion meter.Operation and use should follow manufacturers recommendedprocedures, especially noting any corrections for interferencesto determinations. The chloride-sensitive electrode is notreliable for chloride levels below 2 ppm in Solution A.10.1.4 Ion ChromatographyIt is suitable to use an io
44、nchromatograph, following the manufacturers directions andappropriate techniques for the concentration of the ion in theextraction solution.10.2 Fluoride DeterminationOne of the following testmethods shall be used on a fresh aliquot from Solution A:10.2.1 Specific Ion Electrode Test Method for Fluor
45、ideThe fluoride-sensitive electrode consists of a single-crystallanthanum fluoride membrane, and an internal reference,bonded into an epoxy body. The crystal is an ionic conductorin which fluoride ions are mobile. When the membrane is incontact with a fluoride solution, an electrode potential develo
46、psacross the membrane. This potential, which depends on thelevel of free fluoride ions in solution, is measured against anexternal constant reference potential with a digital pH/mVmeter or specific ion meter. Operation and use should followmanufacturers recommended procedures, especially notingany c
47、orrections for interferences to determinations.10.2.2 SPADNS Colorimetric Test MethodThis colorimet-ric test method is based on the reaction between fluoride and azirconium-dye lake. The fluoride reacts with the dye lake,dissociating a portion of it into a colorless complex anion (ZrF62) and the dye
48、. As the amount of fluoride is increased, thecolor produced becomes progressively lighter or different inhue, depending on the reagent used.10.2.3 Ion Chromatography It is suitable to use and ionchromatograph, following the manufactures directions andappropriate techniques for the concentration of t
49、he ion in theextraction solution.10.3 Silicate DeterminationOne of the following testmethods shall be used on a fresh aliquot from Solution A. IfSolution A is cloudy, it shall be refiltered through a 0.45-mmillipore filter or centrifuged until clear before use.10.3.1 Atomic Absorption Spectrophotometry TestMethodAtomize an aliquot from Solution A by means of anitrous oxide-acetylene flame. The absorption by the siliconatoms of radiation being emitted by a silicon hollow cathodelamp source provides a measure of the amount of siliconpresent in the solutio
