1、Designation: C1318 15C1318 15aStandard 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 indicate
2、s the year 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,
3、 dolomitic and high-calcium limes for total neutralizing capability anddissolved major oxides. Dissolved calcium and magnesium are the major species that neutralize acid under the conditions of thetest.1.2 The test conditions are chosen to measure the acid-neutralizing capacity of both calcium hydro
4、xide and magnesiumhydroxide contained in slaked lime. By controlling the neutralization pH at 6, magnesium hydroxide and magnesium oxide aretitrated in addition to calcium hydroxide fraction.1.3 This test method also determines the fraction of Mg ions present in the lime that will dissolve under lim
5、e flue gasdesulfurization (FGD) conditions. Because the Mg+2+ ion alters FGD performance, it is important to know its concentration.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to addr
6、ess all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C25 Test Methods
7、 for Chemical 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 used by the Industry)C110 Test Methods for Physical Testing of Quicklime, Hydrated L
8、ime, and LimestoneC1301 Test Method for Major and Trace Elements in Limestone and Lime by Inductively Coupled Plasma-Atomic EmissionSpectroscopy (ICP) and Atomic Absorption (AA)E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves3. Terminology3.1 DefinitionsUnless otherwise specified, f
9、or definitions of terms 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 a pH and residence time similar to those found in full-scale FGDreaction tanks.4.2 Asample of lime is titrated with 1N hydrochloric acid, mai
10、ntaining a pH of 6 for 30 min.After 30 min, the acid consumptionis recorded. The total neutralizing capacity is calculated from the acid consumption and reported as CaO.% CaO. Dissolvedmagnesium is determined by spectrometry or by EDTA titration and reported as percent dissolved Magnesium Oxide (as
11、MgO).1 This test method is under the jurisdiction of ASTM Committee C07 on Lime and Limestone and is the direct responsibility of Subcommittee C07.05 on Chemical Tests.Current edition approved June 1, 2015Dec. 1, 2015. Published June 2015January 2016. Originally approved in 1995. Last previous editi
12、on approved in 20092015 asC1318 95 (2009)C1318 15.1. DOI: 10.1520/C1318-15.10.1520/C1318-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document S
13、ummary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recomme
14、nds that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance
15、and Use5.1 There are existing lime-based flue gas desulfurization units in operation that require a method to measure the oxidesavailable for sulfur dioxide absorption. Dissolved magnesium oxide varies among limes depending on the limestone sources andcalcination conditions.6. Interferences6.1 Any s
16、ubstance reacting with acid under the conditions of the test will contribute to the total oxide and dissolved oxidevalues.6.2 Magnesium in forms other than MgO, which dissolve under test conditions, may affect the dissolved MgO and total oxidevalue.values.7. Apparatus7.1 Digital Readout pH Meter, wi
17、th combination electrode readable to 0.01 pH units, or an autotitrator with an automatictemperature compensator capable of titrating to a preset endpoint (Note 1).NOTE 1Use of an automatic titrator is recommended.7.2 Stirrers and Stir Bars.7.3 Inductively Coupled Plasma Spectrometer or Atomic Absorp
18、tion Spectrometer, if not using EDTA titration.7.4 Filtering Funnel, TypeAE glass fiber paper, volumetric flasks (size as needed), 500 mLvolumetric flasks, and various ClassA pipettes.8. Reagents8.1 1.0 Normal Hydrochloric Acid, standardizestandardized using procedures in the section on Available Li
19、me Index in TestMethods C25.8.2 Deionized or Distilled Water, CO2 free.8.3 Calcium and Magnesium Standard Solutions, (commerciallycommercially available or use the procedures in the section onCalcium and Magnesium Oxide (Alternative EDTA Titration Method) in Test Methods C25.8.4 EDTA Standard Soluti
20、on (0.4 %), standardizestandardized according to the procedure in the section on Calcium andMagnesium Oxide (Alternative EDTA Titration Method) in Test Methods C25.8.5 1:1 Hydrochloric Acid, a solution prepared by diluting concentrated Hydrochloric Acid by addition to an approximatelyequal volume of
21、 distilled or deionized water.9. Sample Preparation9.1 The sampling and grinding of any lime sample shall be carried out as rapidly as possible, so that the absorption of moistureand carbon dioxide is held to a minimum.9.2 The sample as received at the laboratory shall be thoroughly mixed and a repr
22、esentative sample with minimum weight of100 g shall be taken and pulverized to pass a 300 m (No. 50) sieve for analysis. Conduct the sieve analysis in accordance withTest Methods C110.9.3 The prepared sample shall be stored in a tightly capped container.10. Procedure10.1 Slaking of Lime Sample:10.1.
23、1 Weigh rapidly 1.402 g of the finely pulverized sample and brush carefully into a 250 mL Erlenmeyer flask containingabout 50 mL of CO2 free deionized or distilled water and immediately stopper the flask.10.1.2 Remove the stopper. Swirl the flask, place on a hot plate, and boil actively 1 min for co
24、mplete slaking. Remove fromthe hot plate, stopper the flask loosely, and place in a cold-water bath to cool to room temperature.10.2 Titration of Sample:10.2.1 Set the pH electrode, burette tip, and temperature sensing device in place, while maintaining agitation.10.2.2 Begin the titration by adding
25、 standard 1.0 normal hydrochloric acid solution. Titrate to and maintain a pH of 66.0 within0.4 pH units for 30 min (Note 2). Time begins from initial addition of acid.NOTE 2When doing a manual titration, the increment of acid addition may require the use of partial drops (suspend a small amount of
26、titrant on theburet tip and wash into the titration flask with CO2 free deionized or distilled water) to avoid exceeding the 0.4 unit limit of pH 6.10.2.3 Record the amount of acid consumed after 30 min.C1318 15a210.2.4 Filter the solution and solution, rinse the flask thoroughly with CO2 free deion
27、ized or distilled water.water, and pass therinse through the filter.10.2.5 Carefully transfer the solution combined filtrate and a rinse to an appropriately sized volumetric flask, add approximately10 mL of 1:1 hydrochloric acid, and dilute to volume.volume with distilled or deionized water. This is
28、 the “Initial Volume.”10.3 Determination of Dissolved Oxides:10.3.1 Spectroscopy:10.3.1.1 From Pipet an aliquot of the diluted solution from the volumetric flask to make the required dilutions to a “FinalVolume” and determine the dissolved magnesium in accordance with Test Method C1301.10.3.1.2 Calc
29、ulate the dissolved magnesium as MgO% MgO according to 11.2.10.3.2 EDTA Titration:10.3.2.1 From the diluted solution prepared in 10.2.5, pipette 20 mL of sample into a 500 mL Erlenmeyer flask and dilute withCO2 free deionized or distilled water to an approximate volume of 100 mL.10.3.2.2 Determine t
30、he total dissolved calcium according to the procedure for Calcium Oxide in the section on Calcium andMagnesium Oxide (Alternative EDTATitration Method) in Test Methods C25. Record mL of EDTAstandard solution required fortitration.10.3.2.3 Repeat 10.3.2 and determine the total dissolved oxides accord
31、ing to the procedure for Magnesium Oxide in the sectionon Calcium and Magnesium Oxide (Alternative EDTA Titration Method) in Test Methods C25. Record mL of EDTA standardsolution required for this titration.11. Calculation of Results11.1 Percent Total Neutralizing Capability (TNC):%TNC as CaO!5A 3B 3
32、C 1W (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 Factor:Dilution factor5Initial Volume see 10.2.5!/Pipette volume for final dilution (2)Dilution factor5 “Final Volume“ see 10.3.1.1!Pipe
33、tted volume of aliquot for final dilution (2)11.2.2 Percent Dissolved Magnesium:%Dissolved Mg11as MgO!5A 3B 3C23DW 31000 (3)%Dissolved Mg21as MgO!5A 3B 3C23D!W 310,000! (3)where:A = concentration of magnesium from instrument ppm Mg+,A = concentration of magnesium from instrument ppm Mg2+,B = dilutio
34、n factor,C2 = chemical factor = 1.658 (MgOMg+),C2 = chemical factor = 1.658 (MgOMg2+),D = final dilution volume, mL, andD = “Initial Volume,” volume, mL, andW = sample weight, g.11.3 EDTA Titration:11.3.1 DilutionAliquot Factor:Dilution factor5Initial Volume see 10.2.5!/titration volume 20 mL! (4)Al
35、iquot factor = “Initial Volume“ see 10.2.5!/titration volume20 mL!# (4)11.3.2 Percent Dissolved Calcium:%Dissolved Ca11as CaO!5A 3B 3C33DW 310 (5)C1318 15a3%Dissolved Ca21as CaO!5A 3B 3C33DW 310 (5)where:A = mL of EDTA standard solution used,B = dilution factor,B = aliquot factor,C3 = chemical facto
36、r = 1.399 (CaO/Ca+),C3 = chemical factor = 1.399 (CaO/Ca2+),D = EDTA titer, mg Ca+/mL EDTA, andD = EDTA titer, mg Ca2+/mL EDTA standard solution, andW = sample weight, g.11.3.3 Percent Total Dissolved Oxides (TDO):%TDO as CaO!5A 3B 3C 33DW 310 (6)where:A = mL of EDTA standard solution used,B = dilut
37、ion factor,B = aliquot factor,C3 = chemical factor = 1.399 (CaO/Ca+),C3 = chemical factor = 1.399 (CaO/Ca2+),D = EDTA titer, mg Ca+/mL EDTA, andD = EDTA titer, mg Ca2+/mL EDTA standard solution, andW = sample weight, g.11.3.4 Percent Dissolved Magnesium:%Dissolved Mg11as MgO!5A 2B! 3C 4 (7)%Dissolve
38、d Mg21as MgO!5A 2B! 3C 4 (7)where:A = % total dissolved oxides,B = % dissolved calcium, andB = % dissolved calcium as CaO, andC4 = chemical factor = 0.7188 (MgO/CaO).12. Precision and Bias12.1 The precision and bias of this test method have not been determined.12.2 When sufficient data has been obta
39、ined and analyzed, a statement of precision will be provided.12.3 The user is cautioned to verify by the use of reference materials, if available, that the bias of the test method is adequatefor the contemplated use.13. Keywords13.1 dissolved calcium; dissolved magnesium; flue gas desulfurization (F
40、GD); lime; pH determination; total neutralizingcapabilityASTM 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 that determination of the validity of any such paten
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