1、Designation: E2403 06 (Reapproved 2012)Standard Test Method forSulfated Ash of Organic Materials by Thermogravimetry1This standard is issued under the fixed designation E2403; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 This standard describes the determination of sulfatedash content (sometimes called residue-on-ignition) of organi
3、cmaterials by thermogravimetry. The method converts commonmetals found in organic materials (such as sodium, potassium,lithium, calcium, magnesium, zinc, and tin) into their sulfatesalts permitting estimation of their total content as sulfates oroxides. The range of the test method is from 0.1 to 10
4、0 %metal content.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement 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
5、to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D874 Test Method for Sulfated Ash from Lubricating Oilsand AdditivesD914 Test Methods for EthylcelluloseD3516 Test Methods for Ash
6、ing CelluloseE473 Terminology Relating to Thermal Analysis and Rhe-ologyE1131 Test Method for Compositional Analysis by Thermo-gravimetryE1142 Terminology Relating to Thermophysical PropertiesE1582 Practice for Calibration of Temperature Scale forThermogravimetryE2040 Test Method for Mass Scale Cali
7、bration of Thermo-gravimetric Analyzers2.2 Other Standards:The United States Pharmacopeia XXII and The NationalFormulary XVII, United States PharmacopeialConvention, Rockville, MD, 1990, Section 281, p. 15273. Terminology3.1 DefinitionsTechnical terms used in this standard aredefined in Terminologie
8、s E473 and E1142.3.1.1 sulfated ash, nthe residue remaining after a speci-men has been oxidized, and the residue subsequently treatedwith sulfuric acid and heated to constant weight.3.1.2 residue-on-ignition, ROI, na commonly used aliasfor sulfated ash.3.1.3 volatiles, nfor the purpose of this test,
9、 those mate-rials evolving as gas at temperatures below 160C in an airatmosphere.4. Summary of Test Method4.1 A test specimen is ignited and burned in an air atmo-sphere at temperatures up to 600C until only ash remains.After cooling, the residue is treated with sulfuric acid andheated to 800C to co
10、nstant weight. The residue remaining isidentified as sulfated ash.4.2 This test method is similar to Test Method D874 forlubricating oils and additives, Test Methods D914 for ethylcellulose, Test Methods D3516 cellulose, and that of TheUnited States Pharmacopeia XXII and makes use of thermo-gravimet
11、ric apparatus to perform the determination.5. Significance and Use5.1 The sulfated ash may be used to indicate the level ofknown metal-containing additives or impurities in an organicmaterial. When phosphorus is absent, barium, calcium,magnesium, sodium and potassium are converted to theirsulfates.
12、Tin and zinc are converted to their oxides.5.2 This standard may be used for research anddevelopment, specification acceptance and quality assurancepurposes.6. Interferences6.1 If phosphorus is present with metals, it partially orwholly remains in the sulfated ash as metal phosphates.1This test meth
13、od is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved Sept. 1, 2012. Published September 2012. Originallyapproved in 2004. Last previous edition approved in 2006 as E2403
14、 06. DOI:10.1520/E2403-06R12.2For 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 standards Document Summary page onthe ASTM website.Copyright ASTM International, 10
15、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Sulfur and chlorides do not interfere.7. Apparatus7.1 Thermogravimetric Analyzer (TGA)The essential in-strumentation required to provide the minimum thermogravi-metric analytical capability for this standard includ
16、es:7.1.1 A thermobalance composed of:7.1.1.1 A furnace to provide uniform controlled heating of aspecimen to a constant temperature of 850C and at a constantrate of 5 to 60C/min7.1.1.2 A temperature sensor to provide an indication of thespecimen or furnace temperature to 61C.7.1.1.3 A continuously r
17、ecording balance to measure thespecimen mass with a minimum capacity of 50 mg and asensitivity of 60.01 mg.7.1.1.4 A means of maintaining the specimen or containerunder atmospheric control of air at a purge flow rate of 50 to100 mL/min 6 5 mL/min.7.1.2 A temperature controller capable of executing a
18、 spe-cific temperature program by operating the furnace betweenselected temperature limit at a rate of 5 to 60C/min and to anisothermal temperature of up to 850C which is maintainedconstant to 610C for a minimum of 70 minutes.7.1.3 A recording device, capable of recording and display-ing any fractio
19、n of the specimen mass signal (TGA curve)including signal noise.7.1.4 Containers (pans, crucibles, etc.) that are inert to thespecimen and to concentrated sulfuric acid and that will remaingravimetrically stable up to 850C. Platinum is a commonmaterial of construction for this purpose.7.2 Graduated
20、micropipette with capacity of 4050 L8. Reagents and Materials8.1 Sulfuric acid, concentrated (98 %), with a relativedensity of 1.84. (WarningPoison. Corrosive. Strong Oxi-dizer.)8.2 AirZero grade or better purity9. Hazards9.1 Sulfuric acid may be corrosive to some thermogravimet-ric apparatus. A reg
21、ular visual inspection of the apparatus willdetermine if any corrosion is taking place.9.2 The exhausted purge gas from the apparatus will containsulfuric acid fumes. This purge gas shall be treated byexhausting to a acid hood or by bubbling through a solution ofsodium bicarbonate to absorb the acid
22、ic fumes.10. Preparation of Apparatus10.1 After turning the power on, allow the instrument toequilibrate for at least one hour prior to any measurements.10.2 Perform any cleaning and calibration procedures de-scribed by the manufacturer in the apparatus OperatorsManual.11. Calibration and Standardiz
23、ation11.1 Perform temperature calibration of the thermogravi-metric analyzer according to Practice E1582 using referencematerials suitable for the temperature range of this method,namely 25 to 800C.11.2 Perform mass calibration of the thermogravimetricanalyzer according to Test Method E2040.12. Proc
24、edure12.1 Transfer 30 to 40 mg of the sample into a tared, clean,and dry sample container. Assemble the thermogravimetricanalyzer for operation. Record the initial weight of the testspecimen as Woto within 60.01 mgNOTE 1The sample container may be preconditioned by heating in anair atmosphere to 800
25、C.NOTE 2Smaller quantities of test specimen will reduce the quantifi-cation capability of this method.12.2 Heat the specimen from ambient to 600C at 10C/minunder an air purge gas with a flow rate of 50 to 100 6 5mL/min and record the thermal curve.12.3 Cool the heated sample and thermogravimetric ap
26、pa-ratus to 20 to 25C.12.4 If desired, record the weight at 150C (Wv) as the massafter apparent loss of volatiles. Record the weight at 600C asthe mass of the residue (Wr).NOTE 3Mass loss due to apparent loss of volatiles at 150C andresidue at 600C are not required for the sulfated ash determination
27、 butmay be recorded for additional sample characterization (see Test MethodE1131.)NOTE 4The temperature at which the mass loss due to volatiles isdetermined may range from 100 to 160C depending upon the material.Other values may be used but shall be reported.12.5 Using a micropipette, add 30 40 L of
28、 98 % gradesulfuric acid to the sample residue (in the container). Reas-semble the instrument for operation.12.6 Heat the specimen from ambient to 800C at 50C/minand hold isothermally at 800 6 25C for 60 6 1 minutes underan air purge at 50 to 100 6 5 mL/min.12.7 Cool the heated specimen and thermogr
29、avimetric ap-paratus to 20 to 25C.12.8 Record the residue mass Ws.12.9 Calculate percent Sulfated Ash (S) using Eq 1.12.10 In the absence of interferences and if the specificmetal in the test specimen is known, then its mass percent (M)may be calculated by multiplying the sulfated ash value by thefa
30、ctors presented in Table 1 using Eq 2.TABLE 1 Sulfated Ash FactorsMetal Sulfated Ash FactorSodium (Na) Na2SO40.3237Potassium (K) K2SO40.4487Lithium (Li) Li2SO40.1263Calcium (Ca) CaSO40.2944Magnesium (Mg) MgSO40.2019Zinc (Zn) ZnO 0.8034Tin (Sn) SnO 0.8812E2403 06 (2012)212.11 If desired, calculate th
31、e Percent Volatiles (V) andPercent Residue (R) using equations 3 and 4, respectively.13. Calculation13.1 Sulfated Ash (S) may be determined using the follow-ing equation:S 5 Ws3100 %/Wo(1)where:S = Sulfated ash, mass %,Ws= Mass of sulfated ash from Section 12.8, mg,Wo= Original mass of the test spec
32、imen from Section 12.1,mg.13.2 If the specific metal in the test specimen is known andif this is the only metal ion present, then its mass percent (M)may be calculated by multiplying the sulfated ash value by thefactors presented in Table 1 using Eq 2.M metal! 5 Factor 3 S (2)where:M = Percent of th
33、e identified metal, mass %.14. Report14.1 Report the sulfated ash (S) to three significant figures.14.2 Report to three significant figures the percent metal(M) when desired and the metal is known.14.3 Provide a copy of the original thermal curve.14.4 The specific dated version of this test method u
34、sed.15. Precision and Bias15.1 An interlaboratory study was conducted in 2005 inwhich lithium cyclohexanebutyrate and calcium oxalate mono-hydrate were tested. Eight laboratories participated in the testusing seven instrument models from two manufacturers. AResearch Report is available from ASTM Hea
35、dquarters.315.2 Precision:15.2.1 Within laboratory variability may be described usingthe repeatability value (r) obtained by multiplying the repeat-ability standard deviation by 2.8. The repeatability valueestimates the 95 % confidence limit. That is, two results fromthe same laboratory should be co
36、nsidered suspect (at the 95 %confidence level) if they differ by more than the repeatabilityvalue.15.2.1.1 The within laboratory repeatability standard devia-tion for lithium in lithium cyclohexanebutyrate was 0.057 %(RSD of 1.5 %) with 20 degrees of experimental freedom.15.2.1.2 The within laborato
37、ry repeatability standard devia-tion for calcium in calcium oxalate monohydrate was 0.24 %(RSD of 0.92 %) with 20 degrees of experimental freedom.15.2.2 Between laboratory variability may be describedusing the reproducibility value (R) obtained by multiplying thereproducibility standard deviation by
38、 2.8. The reproducibilityvalues estimates the 95 % confidence limit. That is, two resultsobtained from different laboratories, operators or apparatusshould be considered suspect (at the 95 % confidence level) ifthey differ by more than the reproducibility value.15.2.2.1 The between laboratory reprod
39、ucibility standarddeviation for lithium in lithium cyclohexanebutyrate was 0.10% (RSD = 2.5 %) with 20 degrees of experimental freedom.15.2.2.2 The between laboratory reproducibility standarddeviation for calcium in calcium oxalate monohydrate was0.32 % (RSD = 1.2 %) with 20 degrees of experimentalf
40、reedom.15.3 Bias:15.3.1 Bias is the difference between the mean value ob-tained and an accepted reference value for the same material.15.3.1.1 The lithium cyclohexanebutyrate used in this studywas supplied (by Sigma-Aldrich, St. Louis, MO) with aCertificate of Analysis indicate an ICP assay of 3.9 %
41、 lithium.The sample is 3.94 % lithium by formula weight.15.3.1.2 The mean value for lithium in lithium cyclo-hexanebutyrate characterized by this method was found to be3.93 %, indicating no detectable bias in this method.16. Keywords16.1 ash; residue on ignition; sulfated ash; thermogravimet-ric ana
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45、own to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting AS
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