1、Designation: C 1271 99 (Reapproved 2006)Standard Test Method forX-ray Spectrometric Analysis of Lime and Limestone1This standard is issued under the fixed designation C 1271; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 test method covers the X-ray emission spectromet-ric analysis of limestone, quicklime, hydrated lime, and hy
3、-draulic lime using wavelength dispersive instruments.1.2 The values stated in SI units are to be regarded as thestandard.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-
4、priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 10.2. Referenced Documents2.1 ASTM Standards:2C25 Test Methods for Chemical Analysis of Limestone,Quicklime, and Hydrated LimeC50 Practi
5、ce for Sampling, Sample Preparation, Packag-ing, and Marking of Lime and Limestone ProductsC51 Terminology Relating to Lime and Limestone (as usedby the Industry)E50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 135 Termino
6、logy Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 305 Practice for Establishing and Controlling Spectro-chemical Analytical Curves3E 456 Terminology Relating to Quality and StatisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Tes
7、t MethodE 1060 Practice for Interlaboratory Testing of Spectro-chemical Methods of AnalysisE 1361 Guide for Correction of Interelement Effects inX-Ray Spectrometric Analysis2.2 NIST Documents:4ANSI-NIST Handbook 114NIST Standards Catalog3. Terminology3.1 Definitions:3.1.1 emission spectroscopyunless
8、 otherwise specified,for definitions of terms used in this test method pertaining toemission spectroscopy, refer to Terminology E 135.3.1.2 limeunless otherwise specified, for definitions ofterms used in this test method pertaining to lime, refer toTerminology C51.3.1.3 statisticalunless otherwise s
9、pecified, for definitionsof terms used in this test method pertaining to statistics, referto Terminology E 456.4. Summary of Test Method4.1 A briquetted powder specimen or a fused-glass diskspecimen is irradiated by a high-energy X-ray beam. Thesecondary X rays produced are dispersed by means of cry
10、stals,and the intensities are measured by suitable detectors atselected wavelengths. Data are collected based on the timerequired to reach a fixed number of counts, total count for afixed time, or integration of voltage for a fixed time. Concen-trations of the elements are determined by relating the
11、 mea-sured radiation of unknown specimens to analytical curvesprepared from reference materials of known composition.5. Significance and Use5.1 This procedure is suitable for manufacturing control andverifying that the product meets specifications. It providesrapid, multi-element determinations with
12、 sufficient accuracy toensure product quality and minimize production delays. Theanalytical performance data included may be used as a bench-mark to determine whether similar X-ray spectrometers pro-vide equivalent precision and accuracy, or whether the perfor-mance of a particular X-ray spectromete
13、r has changed.6. Interferences6.1 Interelement effects or matrix effects may exist for someof the elements listed. One way to compensate for these effects1This test method is under the jurisdiction of ASTM Committee C07 on Limeand is the direct responsibility of Subcommittee C07.05 on Chemical Tests
14、.Current edition approved Feb. 15, 2006. Published March 2006. Originallyapproved in 1994. Last previous edition approved in 1999 as C 1271 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vo
15、lume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohock
16、en, PA 19428-2959, United States.is to prepare a series of calibration curves to cover thedesignated concentration ranges. The composition of the speci-men being analyzed must match closely the composition of thereference materials used to prepare the calibration curve.Mathematical corrections, deri
17、ved from empirical relationshipsor fundamental parameter calculations, may be used alterna-tively.Any of these are acceptable, providing that the analyticalaccuracy required by this test method is achieved.6.2 Calcium is the primary component of the matrix ana-lyzed by this test method. The analyst
18、must be aware of allpossible interferences and matrix effects of this element.Orders of all wavelengths may cause interference, for example,the effect of CaKb1 (2nd order) on PKa1.6.3 Contamination from the grinding apparatus is an ever-present source of interference of which the analyst must always
19、be cognizant. For example, stainless steel will impart iron,chrome, and nickel to the prepared sample.6.4 Spectral interferences from the X-ray tube may alsooccur, for example, line overlap from CrKb1onMnKa1caused by a chrome target tube.7. Apparatus7.1 Specimen Preparation Equipment:7.1.1 Jaw Crush
20、er, for initial crushing of lumps.7.1.2 Plate Grinder or Pulverizer, with one static and onerotating disk for further grinding.7.1.3 Rotary Disk Mill or Shatter Box, with hardenedgrinding containers and timer control for final grinding.7.2 Briquetting Equipment:7.2.1 Briquetting Press, capable of pr
21、oviding pressures upto 550 MPa (80 000 psi). The press shall be equipped with amold assembly that provides a briquet compatible with theX-ray specimen holder.7.3 Fusion Equipment:7.3.1 Furnace or Gas Burners, with a timer, capable ofheating the sample and flux to at least 1000 C and homog-enizing th
22、e melt.7.3.2 Fusion Crucibles:7.3.2.1 Vitreous Carbon or Graphite, 20 to 30-mL capacity,with a flat bottom 30 to 35 mm in diameter.7.3.2.2 Platinum/Gold, 95 % platinum/5 % gold alloy, 30 to35-mL capacity.7.3.2.3 Platinum/Gold Casting Dish, 95 % platinum/5 %gold alloy, 30 to 35-mL capacity, with a fl
23、at bottom 30 to 35mm in diameter.7.3.3 Polishing Wheel, suitable for polishing the fusion diskto obtain a uniform surface for irradiation. The analyst shouldbe aware at all times of possible contamination from thepolishing media used for surfacing the disk (6.3).7.4 Excitation Source:7.4.1 X-Ray Tub
24、e Power Supply, providing constant poten-tial or rectified power of sufficient energy to produce secondaryradiation of the specimen for the elements specified. Thegenerator may be equipped with a line voltage regulator andcurrent stabilizer.7.4.2 X-Ray Tubes, with targets of various high-purityeleme
25、nts, capable of continuous operation at required poten-tials and currents, and that will excite the elements to bedetermined.7.5 Spectrometer, designed for X-ray emission analysis andequipped with specimen holders and a specimen chamber. Thechamber may contain a specimen spinner, and it must beequip
26、ped for vacuum operation.7.5.1 Analyzing CrystalsFlat or curved crystals with op-timized capability for diffraction of the wavelengths of interest.7.5.2 Collimator, for limiting the characteristic X rays to aparallel bundle when flat crystals are used in the instrument. Acollimator is not necessary
27、for curved crystal optics.7.5.3 Detectors, sealed or gas flow, proportional type, Gei-ger counters, scintillation counters or equivalent.7.5.4 Vacuum System, providing for the determination ofelements whose radiation is absorbed by air (atomic numberbelow 20). The system shall consist of at least on
28、e vacuumpump, gage, and electrical controls to provide automaticpumpdown of the optical path and maintain a controlledpressure, usually 13 Pa or less.7.6 Measuring System, consisting of electronic circuits ca-pable of counting or integrating pulses received from thedetectors. The counts, count rate,
29、 or integrated voltages may bedisplayed on meters, recorders, digital counters, or voltmeters.The counts, count rates, or integrated voltages can also bepresented to a computer or programmable calculator forconversion to percent concentration. Pulse height analyzersmay be required to provide more ac
30、curate measurements forsome measurements.8. Reagents and Materials8.1 Purity and Concentration of ReagentsThe purity andconcentration of chemical reagents shall conform to the re-quirements prescribed in Practices E50.8.2 BindersVarious binders have been used successfullyto prepare briquettes suitab
31、le for presentation to the instrument.As a general rule, the binder should not contain an element thatwill be determined. In addition, the sample to binder ratio mustbe present in the analytical sample as in the reference materialsthat were used to establish the calibration.8.3 FluxesVarious fluxes
32、have been used successfully toprepare fusion disks. The flux must be capable of dissolving ordispersing the analyzed elements in an homogeneous andreproducible fashion in the melt. The prepared disks must thenbe suitable for presentation to the instrument.8.4 Detector Gas (P-10), consisting of a mix
33、ture of 90 %argon and 10 % methane for use with gas flow proportionalcounters only.9. Reference Materials9.1 Certified reference materials are available from theNational Institute for Standards and Technology (NIST) andother international certification agencies. Refer to Test Meth-ods C25for a curre
34、nt listing.9.2 Reference materials with matrixes similar to that of thetest specimen and containing varying amounts of the elementsto be determined may be used provided that they have beenanalyzed in accordance with ASTM standard test methods.9.3 Standard additions method or spiked samples may alsob
35、e used to create standards for which appropriate referenceC 1271 99 (2006)2materials are not available for an element desired to beanalyzed. The matrix material must match that of the testspecimen.10. Safety Precautions10.1 Occupational health and safety standards for ionizingradiation shall be obse
36、rved at all X-ray emission spectrometerinstallations. It is also recommended that operating and main-tenance personnel follow the guidelines of safe operatingprocedures given in current handbooks and publications fromthe original equipment manufacturer, NIST, U.S. GovernmentPrinting Office, or simil
37、ar handbooks on radiation safety. SeeNIST Standards Catalog and ANSI-NIST Handbook 114.10.2 PersonnelX-ray equipment shall be used only underthe guidance and supervision of a responsible, qualified person.10.3 Monitoring DevicesEither film badges or dosimetersshall be worn by all operating and maint
38、enance personnel.Periodic radiation surveys of the equipment for leaks andexcessive scattered radiation shall be made by a qualifiedperson using an ionization chamber detector to meet local,state, and federal radiation standards. The personal film badgesurvey record, the radiation survey record, and
39、 an equipmentmaintenance record shall be available upon request.10.4 Special precautions for operators and maintenancepersonnel shall be posted at the equipment site.10.5 Radiation caution signs shall be posted near the X-rayequipment and at all entrances to the radiation area.10.6 Fail-Safe “X-ray
40、on” warning lights shall be used onthe equipment.11. Sampling11.1 Gross sample is to be taken in accordance withMethods C50.11.2 Sample preparation is to be performed in accordancewith Methods C50and Test Methods C25.11.3 Special preparation may be required to grind theanalytical sample finer than i
41、s required in 11.2.12. Preparation of Reference Materials and TestSpecimens12.1 Treat reference materials and specimens exactly thesame way throughout the procedure. Either briquetted powderor fused disk specimens may be used.13. Preparation of Apparatus13.1 Prepare and operate the spectrometer in a
42、ccordancewith the manufacturers instructions, using the parametersgiven in Table 1. Once established, control all instrumentparameters closely to ensure repeatable analyses.14. Calibration and Standardization14.1 Calibration (Preparation of Analytical Curves)Select a sufficient number of reference m
43、aterials to cover theconcentration ranges of the elements sought.Average duplicateintensity measurements of each reference material, and estab-lish a calibration curve for each element in accordance withPractice E 305. Establish the curve by a least squares ormultiple regression fit of the X-ray int
44、ensity measurementsversus the corresponding weight percent concentrations of theelement in the reference materials.14.2 Standardization (Analytical Curve Adjustment)Verify that the calibration curve for each element has notdrifted using a control reference material. Drift is indicated bya change in
45、counts that exceeds the normal variation of countsfor that element. A change of 1 % or greater usually signifiesthat the calibration curve for that element has drifted andshould thus be adjusted. Re-measure the reference materials toverify that acceptable analyses are obtained after the adjust-ments
46、 are made.15. Procedure15.1 ExcitationIntroduce the specimen into the specimenchamber, using care not to contaminate the surface to beexcited. Produce the secondary fluorescence using the equip-ment used in 7.4.15.2 Radiation MeasurementsObtain and record thecounting rate measurement for each elemen
47、t. Either fixed countor fixed time modes may be used. A predetermined minimumcount rate is obtainable only after unacceptable long countingtimes for lime materials, with the exception of the major oxides(Si, Fe, Al, Ca, and Mg). A minimum counting time of 60 s isacceptable.15.3 Spectral Interference
48、sSome X-ray spectrometerswill not resolve radiation completely from several line over-laps. Care must therefore be exercised in these cases. Alternatewavelengths without interference may be used. Otherwise,mathematical calculations must be used to correct for theinterferences.NOTE 1If a goniometer i
49、s used, the setting for the 2 u peak must bedetermined experimentally within each laboratory. Periodic checks toverify the setting are advisable.15.4 Replicate MeasurementsMake a minimum of twomeasurements on each test specimen. The performance of anX-ray spectrometer is not improved significantly by makingmultiple measurements on the same surface of the samespecimen; however, for those elements not having sufficientcounts in the predetermined time, the statistics near thedetection limit will improve with multiple exposures. Confi-dence in the accuracy of analysis w
