1、Designation: D1318 00 (Reapproved 2011)Standard Test Method forSodium in Residual Fuel Oil (Flame Photometric Method)1This standard is issued under the fixed designation D1318; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 the determination of sodium inresidual fuel oil by means of a flame photometer. Its prec
3、isionin low ranges limits its application to samples containing morethan 15 mg/kg sodium. Other elements commonly found inresidual fuel oil do not interfere.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 d
4、oes not purport to address all of thesafety problems associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements see 6.3,6.5, 6.
5、7, 8.2, and Note 3.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products3. Summary of Test Method3.1 A weighed sample is reduced to
6、a carbonaceous ashunder controlled conditions. The residual carbon is removed byheating in a muffle furnace at 550C. The ash is dissolved,diluted to volume, and the sodium determined by means of aflame photometer.4. Significance and Use4.1 Excessive amounts of sodium can indicate the presenceof mate
7、rials that cause high wear of burner pumps and valves,and contribute to deposits of boiler heating surfaces.5. Apparatus5.1 Flame Photometer, capable of isolating the sodiumdoublet at 589 nm and stable enough to give repeatablemeasurements that do not vary more than 5 % of their mean inthe 2 to 20 m
8、g/kg range of sodium.5.2 Platinum Dish, 100-mL capacity, approximately 35 mmin depth.5.3 Electric Muffle Furnace, capable of operating over avariable range from 200 to 600C and of maintaining atemperature of 550 6 50C.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beuse
9、d in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades can beused, provided it is first ascertained that the reagen
10、t is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II or III of Specification D1193.6.3 Hydrochloric Acid (sp gr 1.19)Concen
11、trated hydro-chloric acid (HCl). (WarningPoison. Causes severe burns.Harmful or fatal if swallowed or inhaled.)6.4 Hydrochloric Acid (1+9)Mix 1 volume of HCl (sp gr1.19) with 9 volumes of water.6.5 Hydrofluoric Acid (48 %)Concentrated hydrofluoricacid (HF). (WarningPoison. Causes severe burns. Harmf
12、ulor fatal if swallowed or inhaled.)6.6 Sodium Solution, Standard (1000 mg Na/L)Dissolve3.088 6 0.005 g of dried sodium sulfate (Na2SO4) in water anddilute to 1 L in a volumetric flask. Store in a polyethylenebottle.6.7 Sulfuric Acid (1+1)Carefully add, while stirring, 1volume of concentrated sulfur
13、ic acid (H2SO4, sp gr 1.84) to 11This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved May 1, 2011. Published May 2011. Originallyapproved in 1954. Las
14、t previous edition approved in 2005 as D1318 00 (2005).DOI: 10.1520/D1318-00R11.2For 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
15、onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Unite
16、d States Pharmacopeiaand National Formulary , U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.volume of water. (WarningPoison. Causes severe burns.Harmful or fatal if swallowed
17、 or inhaled.)7. Sampling7.1 Sampling shall be done in accordance with PracticesD4057 or Test Method D4177.7.2 Use a clear, clean glass pint bottle, previously rinsedtwice with HCl (1+9) and once with water and allowed to dry,for sampling the bulk material or plant streams. Obtain arepresentative sam
18、ple but do not fill the bottle more than abouttwo-thirds full. Warm viscous samples until they can be mixedreadily. Stir up any material that has settled out and shake thesample for 3 min just prior to weighing it out.7.3 Optimum sample size for most instruments is that whichcontains from 0.5 to 1.0
19、 mg of sodium. Estimate the samplesize as follows (see Note 1):Sample size, g 5 750/estimated sodium content, mg/kg (1)NOTE 1An estimate of the maximum amount of sodium in a samplecan be obtained from its ash value. For example, an ash of 0.01 % wouldundoubtedly have less than 0.005 % sodium (50 ppm
20、). If there is noestimate as to the probable sodium range in a sample, it is more expedientto weigh out a large amount, for example 60 g, because the test methodprovides for dilution of sample solutions that are more concentrated thanthe standards.8. Calibration8.1 Dilute the sodium solution (1000 m
21、g Na/L) so as toobtain solutions containing 2, 4, 6, 8, 10, 12, 15, 18, and 20mg/L (approximately equivalent to mg/kg). Store all dilutesodium solutions in polyethylene bottles.8.2 Prepare the flame photometer for use as described in themanufacturers instruction manual. Carefully adjust the pres-sur
22、e of the gases (WarningDangerous.) used for flamecombustion in the order described by the manufacturer untiloptimum control is achieved. Select a standard approximatelyin the middle of the optimum range of the instrument beingused. While atomizing this medium-range standard, adjust thewavelength sel
23、ector to the greatest response for the sodiumdoublet at about 589 nm and adjust all controls of theinstrument to optimum performance. Finally, adjust the sensi-tivity control to give a proper scale reading.8.3 Atomize each of the standard solutions and record thescale response for each. Run repeat c
24、hecks on the medium-range standard selected in 6.2 after each of these standards todetermine whether the flame photometer is functioning prop-erly. Make the indicated adjustments, if required, and rerun thestandards.8.4 Prepare a working curve by plotting the milligrams ofsodium per litre against th
25、e scale readings.9. Procedure9.1 Preparation of Sample:9.1.1 Weigh into a thoroughly clean, dry 100-mL platinumdish the appropriate size sample (7.3) with an accuracy of atleast 1 part per 100 parts of sample (Note 2). Samples largerthan 75 g require a second filling of the platinum dish; for suchsa
26、mples, obtain the sample weight from the difference betweenthe initial and final weights of the sample bottle. Place theplatinum dish containing the fuel oil on a silica triangleproperly supported, and heat with a bunsen burner until thecontents ignite and burn readily (Note 3). Continue heatingwith
27、 the burner in such a manner that the sample burns at auniform and moderate rate and only ash and carbon remainafter burning ceases. For samples larger than 75 g, cool the dishand fill it approximately two-thirds full with additional well-shaken sample, and burn as above.NOTE 2Handle the platinum di
28、sh only with platinum-tip tongs and donot touch it with the fingers during the test. Carefully dust the bottom ofthe dish with a clean camel-hair brush before each weighing.NOTE 3If sample contains an appreciable amount of water, asindicated by spattering when heated, add a few millilitres of ethyl-
29、alcohol(95 %) (WarningFlammable) or isopropyl alcohol (99 %) (WarningFlammable) before heating. Include the alcohol in the blank determina-tion.9.1.2 Place the dish in a muffle furnace at no more than200C (Note 3). Slowly raise the temperature to 550 6 50C.Leave the muffle door slightly ajar until o
30、nly a little carbonremains in the dish; then close the door and continue theignition until no carbon is visible.NOTE 4The platinum dishes should be placed on silica plates or silicatriangles on the floor of the muffle furnace. Particular care must beexercised to avoid contamination of the sample wit
31、h particles from theroof, walls, and the door of the furnace. During the initial ignition, theopening of the muffle door must be carefully adjusted so that the air flowinto the muffle is not excessive. Too great an air flow causes hightemperatures in the burning carbon and also possible loss of ash
32、from thedish.9.1.3 Cool the dish to room temperature, add 1 mL ofH2SO4(1+1) and about 1 mL of HF to the platinum dish (Note5), evaporate to dryness under a hood, and replace the dish inthe muffle furnace at 550 6 50C for 15 min.NOTE 5Unless the silica is removed, low values will result from theocclu
33、sion of sodium in the insoluble residue.9.1.4 Cool the platinum dish, wash down its sides withabout 10 mL of water and, by means of a dropper, add 2 dropsof H2SO4(1+1). Heat the dish on a steam bath, to effect thesolution of the sodium salts, until approximately 1 mL of liquidremains. Remove from th
34、e steam bath, add 5 to 10 mLof water,and filter the solution through an acid-washed filter paper or anacid-washed, sintered-glass filter into a 100-mL volumetricflask. Wash the dish and filter with water, collecting the washwater in the volumetric flask. Dilute to 100 mL with water andmix. If the as
35、hed sample is known to contain less than 0.5 mgof sodium, make a proportionately smaller dilution to obtain 5to 10 mg of sodium per litre in the final solution.9.2 Photometric Measurement:9.2.1 Put the flame photometer into operation, using theidentical burner and instrument settings that were deter
36、minedduring calibration in accordance with 8.2. Vaporize themedium-range standard solution (8.2) and adjust the sensitivitycontrol to give the same scale reading that was obtained whenthe calibration curve was prepared.9.2.2 Atomize a portion of the sample solution prepared in9.1.4 in the flame phot
37、ometer. If it is in the optimum range forthe instrument in use, proceed as directed in 9.2.3.Ifitistooconcentrated, place a few millilitres in a graduated cylinder,D1318 00 (2011)2dilute to a known volume with water, and atomize. If neces-sary, repeat this operation to determine the correct dilution
38、.When this is established, make the proper accurate dilution bypipetting an aliquot from the original 100-mL volumetric flaskinto another volumetric flask and dilute to the mark with water.9.2.3 Atomize the properly diluted sample solution, recordthe scale reading, and obtain the sodium concentratio
39、n inmilligrams per litre by reference to the standard curve preparedin 8.4. Also atomize standards just lower and higher than theunknown to check the validity of the calibration curve.9.2.4 Perform a blank determination on all of the reagents,including the water, in accordance with the procedure jus
40、tdescribed.10. Calculation and Report10.1 Calculate the sodium concentration, in parts per mil-lion as follows:Sodium, mg in sample 5 A 2 B! 3 CE/1000D (2)Sodium, mg/kg 5mg of sodium 3 1000!/Wwhere:A = sodium concentration of the sample solution, mg/L,B = sodium concentration in the reagent blank, m
41、g/L,C = volume to which ashed sample was originally diluted,mL,D = volume of aliquot taken from original dilution, mLE = volume to which aliquot D was diluted, mL andW = weight of sample used, g,10.2 Report the results to the nearest 1 mg/kg.11. Precision and Bias11.1 PrecisionThe following criteria
42、 should be used forjudging the acceptability of results (95 % confidence):11.1.1 RepeatabilityThe difference between successivetest results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, would, in the long run in the normal and co
43、rrectoperation of the test method, exceed the following values onlyin one case in twenty:Sodium, mg/kg Repeatability, mg/kg15 to 40 440 to 85 611.1.2 ReproducibilityThe difference between two singleand independent results, obtained by different operators work-ing in different laboratories on identic
44、al test material, would, inthe long run in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:Sodium, ppm Reproducibility, ppm15 to 25 925 to 50 1550 to 90 2311.2 BiasSince there is no accepted reference materialsuitable for determining the bias
45、 for the procedure in this testmethod, no statement on bias is being made.ASTM 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
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