1、Designation: C1318 15Standard Test Method forDetermination of Total Neutralizing Capability and DissolvedCalcium and Magnesium Oxide in Lime for Flue GasDesulfurization (FGD)1This standard is issued under the fixed designation C1318; the number immediately following the designation indicates the yea
2、r oforiginal adoption 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.1. Scope1.1 This test method covers analysis of magnesian, dolo-mit
3、ic and high-calcium limes for total neutralizing capabilityand dissolved major oxides. Dissolved calcium and magnesiumare the major species that neutralize acid under the conditionsof the test.1.2 The test conditions are chosen to measure the acid-neutralizing capacity of both calcium hydroxide and
4、magne-sium hydroxide contained in slaked lime. By controlling theneutralization pH at 6, magnesium hydroxide and magnesiumoxide are titrated in addition to calcium hydroxide fraction.1.3 This test method also determines the fraction of Mg ionspresent in the lime that will dissolve under lime flue ga
5、sdesulfurization (FGD) conditions. Because the Mg+ion altersFGD performance, it is important to know its concentration.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thes
6、afety 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:2C25 Test Methods for Chemical
7、 Analysis of Limestone,Quicklime, and Hydrated LimeC50 Practice for Sampling, Sample Preparation, Packaging,and Marking of Lime and Limestone ProductsC51 Terminology Relating to Lime and Limestone (as usedby the Industry)C110 Test Methods for Physical Testing of Quicklime,Hydrated Lime, and Limeston
8、eC1301 Test Method for Major and Trace Elements in Lime-stone and Lime by Inductively Coupled Plasma-AtomicEmission Spectroscopy (ICP) and Atomic Absorption(AA)E11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 DefinitionsUnless otherwise specified, for definitionsof t
9、erms used in these test methods refer to Terminology C51.4. Summary of Test Method4.1 Lime is slaked by boiling and is reacted with acid at apH and residence time similar to those found in full-scale FGDreaction tanks.4.2 A sample of lime is titrated with 1N hydrochloric acid,maintaining a pH of 6 f
10、or 30 min. After 30 min, the acidconsumption is recorded. The total neutralizing capacity iscalculated from the acid consumption and reported as CaO.Dissolved magnesium is determined by spectrometry or byEDTA titration and reported as percent dissolved MagnesiumOxide (as MgO).5. Significance and Use
11、5.1 There are existing lime-based flue gas desulfurizationunits in operation that require a method to measure the oxidesavailable for sulfur dioxide absorption. Dissolved magnesiumoxide varies among limes depending on the limestone sourcesand calcination conditions.6. Interferences6.1 Any substance
12、reacting with acid under the conditionsof the test will contribute to the total oxide and dissolved oxidevalues.6.2 Magnesium in forms other than MgO, which dissolveunder test conditions, may affect the dissolved MgO and totaloxide value.1This test method is under the jurisdiction of ASTM Committee
13、C07 on Limeand Limestone and is the direct responsibility of Subcommittee C07.05 on ChemicalTests.Current edition approved June 1, 2015. Published June 2015. Originallyapproved in 1995. Last previous edition approved in 2009 as C1318 95 (2009)1.DOI: 10.1520/C1318-15.2For referenced ASTM standards, v
14、isit 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, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
15、2959. United States17. Apparatus7.1 Digital Readout pH Meter, with combination electrodereadable to 0.01 pH units, or an autotitrator with an automatictemperature compensator capable of titrating to a presetendpoint (Note 1).NOTE 1Use of an automatic titrator is recommended.7.2 Stirrers and Stir Bar
16、s.7.3 Inductively Coupled Plasma Spectrometer or AtomicAbsorption Spectrometer, if not using EDTA titration.7.4 Filtering Funnel, Type AE glass fiber paper, volumetricflasks (size as needed), 500 mL volumetric flasks, and variousClass A pipettes.8. Reagents8.1 1.0 Normal Hydrochloric Acid, standardi
17、ze using pro-cedures in the section onAvailable Lime Index in Test MethodsC25.8.2 Deionized or Distilled Water, CO2free.8.3 Calcium and Magnesium Standard Solutions (commer-cially available or use the procedures in the section on Calciumand Magnesium Oxide (Alternative EDTATitration Method) inTest M
18、ethods C25.8.4 EDTA Standard Solution (0.4 %), standardize accordingto the procedure in the section on Calcium and MagnesiumOxide (Alternative EDTA Titration Method) in Test MethodsC25.9. Sample Preparation9.1 The sampling and grinding of any lime sample shall becarried out as rapidly as possible, s
19、o that the absorption ofmoisture and carbon dioxide is held to a minimum.9.2 The sample as received at the laboratory shall bethoroughly mixed and a representative sample with minimumweight of 100 g shall be taken and pulverized to pass a 300 m(No. 50) sieve for analysis. Conduct the sieve analysis
20、inaccordance with Test Methods C110.9.3 The prepared sample shall be stored in a tightly cappedcontainer.10. Procedure10.1 Slaking of Lime Sample:10.1.1 Weigh rapidly 1.402 g of the finely pulverizedsample and brush carefully into a 250 mL Erlenmeyer flaskcontaining about 50 mL of CO2free deionized
21、or distilledwater and immediately stopper the flask.10.1.2 Remove the stopper. Swirl the flask, place on a hotplate and boil actively 1 min for complete slaking. Removefrom the hot plate, stopper the flask loosely and place in acold-water bath to cool to room temperature.10.2 Titration of Sample:10.
22、2.1 Set the pH electrode, burette tip, and temperaturesensing device in place, while maintaining agitation.10.2.2 Begin the titration by adding standard 1.0 normalhydrochloric acid solution. Titrate to and maintain a pH of 6within 0.4 pH units for 30 min (Note 2). Time begins frominitial addition of
23、 acid.NOTE 2When doing a manual titration, the increment of acid additionmay require the use of partial drops (suspend a small amount of titrant onthe buret tip and wash into the titration flask with CO2free deionized ordistilled water) to avoid exceeding the 0.4 unit limit of pH 6.10.2.3 Record the
24、 amount of acid consumed after 30 min.10.2.4 Filter the solution and rinse the flask thoroughly withCO2free deionized or distilled water.10.2.5 Carefully transfer the solution to an appropriatelysized volumetric flask, add approximately 10 mL of 1:1hydrochloric acid, and dilute to volume.10.3 Determ
25、ination of Dissolved Oxides:10.3.1 Spectroscopy:10.3.1.1 From the diluted solution make the required dilu-tions and determine the dissolved magnesium in accordancewith Test Method C1301.10.3.1.2 Calculate the dissolved magnesium as MgO ac-cording to 11.2.10.3.2 EDTA Titration:10.3.2.1 From the dilut
26、ed solution pipette 20 mL of sampleinto a 500 mL Erlenmeyer flask and dilute with CO2freedeionized or distilled water to an approximate volume of100 mL.10.3.2.2 Determine the total dissolved calcium according tothe procedure for Calcium Oxide in the section on Calcium andMagnesium Oxide (Alternative
27、 EDTA Titration Method) inTest Methods C25. Record mL of EDTA required for titration.10.3.2.3 Repeat 10.3.2 and determine the total dissolvedoxides according to the procedure for Magnesium Oxide in thesection on Calcium and Magnesium Oxide (Alternative EDTATitration Method) in Test Methods C25. Reco
28、rd mL of EDTArequired for this titration.11. Calculation of Results11.1 Percent Total Neutralizing Capability (TNC):% TNC as CaO! 5A 3 B 3 C1W(1)where:A = mL HCl used in 10.2.3,B = normality HCl,C1= chemical factor = 2.804 (mequi of CaO/10), andW = sample weight, g.11.2 Spectroscopy:11.2.1 Dilution
29、Factor:Dilution factor5 Initial Volume see 10.2.5!/Pipette volume for final dilution(2)11.2.2 Percent Dissolved Magnesium:% Dissolved Mg11as MgO! 5A 3 B 3 C23 DW 31000(3)where:A = concentration of magnesium from instrument ppmMg+,C1318 152B = dilution factor,C2= chemical factor = 1.658 (MgO Mg+),D =
30、 final dilution volume, mL, andW = sample weight, g.11.3 EDTA Titration:11.3.1 Dilution Factor:Dilution factor 5 Initial Volume see 10.2.5!/titration volume 20 mL!(4)11.3.2 Percent Dissolved Calcium:% Dissolved Ca11as CaO! 5A 3 B 3 C33 DW 310(5)where:A = mL of EDTA standard solution used,B = dilutio
31、n factor,C3= chemical factor = 1.399 (CaO/Ca+),D = EDTA titer, mg Ca+/mL EDTA, andW = sample weight, g.11.3.3 Percent Total Dissolved Oxides (TDO):% TDO as CaO! 5A 3 B 3 C33 DW 310(6)where:A = mL of EDTA standard solution used,B = dilution factor,C3= chemical factor = 1.399 (CaO/Ca+),D = EDTA titer,
32、 mg Ca+/mL EDTA, andW = sample weight, g.11.3.4 Percent Dissolved Magnesium:% Dissolved Mg11as MgO! 5 A 2 B! 3 C4(7)where:A = % total dissolved oxides,B = % dissolved calcium, andC4= chemical factor = 0.7188 (MgO/CaO).12. Precision and Bias12.1 The precision and bias of this test method have notbeen
33、 determined.12.2 When sufficient data has been obtained and analyzed, astatement of precision will be provided.12.3 The user is cautioned to verify by the use of referencematerials, if available, that the bias of the test method isadequate for the contemplated use.13. Keywords13.1 dissolved calcium;
34、 dissolved magnesium; flue gasdesulfurization (FGD); lime; pH determination; total neutral-izing capabilityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised th
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