1、Designation: E 223 96 (Reapproved 2002)e1Standard Test Methods forAnalysis of Sulfuric Acid1This standard is issued under the fixed designation E 223; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEThe value for the 95 % range for Repeatability of 0.004 % NVM
3、was changed from 0.007 to 0.0023 in Table 2 inJune 2003.1. Scope1.1 These test methods cover the analysis of sulfuric acid.1.2 The analytical procedures appear in the following order:SectionsTotal Acidity 8 to 16Baum Gravity 17 to 26Nonvolatile Matter 27 to 33Iron 34 to 43Sulfur Dioxide 44 to 51Arse
4、nic 52 to 611.3 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Sp
5、ecific hazardsstatements are given in Section 5.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 1 Specification for ASTM Thermometers3E 60 Practice for Analysis of Metals, Ores, and RelatedMaterials by Molecular Absorption Spectrometry4E 180 Practice for Determinin
6、g the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals5E 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis53. Significance and Use3.1 These test methods provide for the classification ofvarious grades of sulfur
7、ic acid and for the determination ofvarious impurities. Acid strength and impurity levels areimportant factors in many uses of sulfuric acid.4. Purity of Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall
8、 conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy o
9、f the determination.4.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type II or Type IIIreagent water conforming to Specification D 1193.5. Hazards5.1 Sulfuric acid is a strong corrosive acid and is dangerousif improperly handled. Avoid any skin or eye co
10、ntact.5.2 Clean up all spills immediately by covering the spillwith vermiculite or some other inert absorbent material andsweeping into a pan. Dispose of the absorbent by flooding withwater and discarding in a suitable container. Flush the area withwater.6. Photometers and Photometric Practice6.1 Ph
11、otometers and the photometric practice used in thesetest methods shall conform to Practice E 60.7. Sampling7.1 Sampling of sulfuric acid is not within the scope of thesetest methods.7.2 The sample to be analyzed shall be considered to be thatsample in a single bottle submitted to the analytical labo
12、ratory.1These test methods are under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and are the direct responsibility of Subcommit-tee E15.02 on Product Standards.Current edition approved Oct. 10, 2002. Published February 2003. Originallyapproved in 1965. Last previous e
13、dition approved in 1996 as E 223 96.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 14.03.4Annual Book of ASTM Standards, Vol 03.05.5Annual Book of ASTM Standards, Vol 15.05.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washingt
14、on, 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 United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright AS
15、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.3 The size of the sample shall be sufficient to perform allanalyses without the reuse of any portion of the sample.TOTAL ACIDITY8. Scope8.1 This test method covers the determination of the totalac
16、idity of 75 to 99 % sulfuric acid. Two test methods are givenfor weighing the sample, namely, the Dely tube and the snaketube test methods.9. Summary of Test Method9.1 A weighed sample of acid is diluted in water and titratedwith standardized 0.5 N sodium hydroxide solution, usingphenolphthalein as
17、the indicator.10. Interferences10.1 Acids other than sulfuric and compounds that consumesodium hydroxide will affect the accuracy of this test method.11. Apparatus11.1 Dely Tube (Fig. 1) or Snake Tube (Fig. 2).711.2 Buret, 100-mL, Class A, bulb-type.12. Reagents12.1 Phenolphthalein Indicator Solutio
18、n (10 g/L)Dissolve1gofphenolphthalein in 100 mL of ethanol (95 %),methanol, or isopropanol.812.2 Sodium Hydroxide, Standard Solution (0.5 N)SeePractice E 200.13. Procedure13.1 Dely Tube Test MethodInvert the sample bottleseveral times. (Hold the stopper in tight.) Insert the long arm ofa dry, weighe
19、d Dely tube and withdraw by suction a convenientsize sample depending upon the acid strength as given in Table1 (Note 1). Invert the Dely tube and wipe the acid from thelong arm with disposable tissue several layers thick. Discardthe tissue immediately to avoid burning the fingers. Reweigh tothe nea
20、rest 0.0001 g and record the weight of the sample.Incline the tube so that the acid runs back nearly to the bend ofthe short arm. Attach the short arm to an elevated waterreservoir by means of a rubber tube closed near the lower endwith a pinch clamp. Insert the long arm of the Dely tube into400-mL
21、glass beaker containing approximately 100 mL ofwater. Open the pinch clamp and flush the sample into thebeaker. Continue the flow of water until all acid is washed fromthe Dely Tube (Note 2 and Note 3). Wash the long end of theDely tube, collecting the washings in the beaker. Add 3 to 5drops of phen
22、olphthalein indicator solution. Record the tem-perature of the 0.5 N NaOH solution, and then titrate thesample to a pink end point. Record the titration to the nearest0.02 mL.NOTE 1The Dely tube can be marked at points equivalent to weightsgiven in Table 1.7Suitable Dely and snake tubes are availabl
23、e from Corning Glass Works,Corning, NY.8This reagent is also described in Practice E 200.FIG. 1 Dely TubeFIG. 2 Snake TubeTABLE 1 Sample Size for Total AcidityH2SO4, % Sample Size, g98 1.9 to 2.294 2.0 to 2.390 2.1 to 2.485 2.2 to 2.680 2.3 to 2.777 2.4 to 2.875 2.5 to 2.9E 223 96 (2002)e12NOTE 2The
24、 presence of acid in the Dely tube may be detected bycoloring the water in the reservoir with phenolphthalein indicator and theminimum amount of dilute NaOH solution that will produce a slight pink.The water flowing through the tube is dicolorized as long as acid ispresent, and the appearance of a p
25、ink color indicates the absence of acid.NOTE 3The acid and water are separated by a bubble of air.13.2 Snake Tube Test MethodInvert the sample bottleseveral times. (Hold the stopper in tight). Insert the capillaryend of a dry, weighed snake tube and withdraw by suction aconvenient size sample depend
26、ing upon the acid strength asgiven in Table 1. Invert the tube so that the double bend is ina horizontal position. Wipe the acid from the capillary withdisposable tissue several layers thick. Discard the tissueimmediately to avoid burning the fingers. Reweigh to thenearest 0.0001 g and record the we
27、ight of the sample. Sub-merge the capillary of the tube in approximately 100 mL ofwater contained in the 400-mL beaker. Force the weighedsample from the tube by a stream of water from a wash bottleby placing the delivery tip in the exposed end of the snake tube(Note 4). Wash the tube with 50 to 70 m
28、L of water. Remove thetube and wash the outside free of acid. Swirl the contents of thebeaker gently while washing. Accumulate all washings in thebeaker and add 3 to 5 drops of phenolphthalein indicatorsolution. Record the temperature of the 0.5 N NaOH solution,and then titrate the sample to a pink
29、end point. Record thetitration to the nearest 0.02 mL.NOTE 4Do not introduce the water into the snake tube too rapidly, asthis will cause spattering.14. Calculation14.1 If necessary, correct the buret reading for calibrationerrors and record the volume of titrant as V and the temperatureas t.14.2 Co
30、rrect the normality of the sodium hydroxide stan-dard solution for any difference in temperature between time ofstandardization and time of use according to the followingequation:N 5 Ns1 0.00014 s 2 t! (1)where:N = normality of NaOH solution at temperature t duringuse,Ns= normality of NaOH solution
31、at temperature s duringstandardization,s = temperature of NaOH solution during standardization,andt = temperature of NaOH solution during analysis.14.3 Calculate the total acidity as percentage of sulfuric acidas follows:Sulfuric acid, wt % 5VN 3 0.04904!W3 100 (2)where:V = corrected millilitre of N
32、aOH solution required fortitration of the sample,N = normality of the NaOH solution, andW = grams of sample used.15. Report15.1 Report the percentage of sulfuric acid to the nearest0.01 %.16. Precision and Bias16.1 The following criteria should be used for judging theacceptability of results (see No
33、te 5):16.1.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estimated to be0.069 % absolute at 56 df. The 95 % limit for the differencebetween two such runs is 0.19 % absolute.16.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability), Former
34、ly Called RepeatabilityThe stan-dard deviation of results (each the average of duplicates),obtained by the same analyst on different days, has beenestimated to be 0.104 % absolute at 28 df. The 95 % limit forthe difference between two such averages is 0.29 % absolute.16.1.3 Reproducibility (Multilab
35、oratory)The standard de-viation of results (each the average of duplicates), obtained byanalysts in different laboratories, has been estimated to be0.124 % absolute at 7 df. The 95 % limit for the differencebetween two such averages is 0.35 % absolute.NOTE 5These precision estimates are based on an
36、interlaboratorystudy of analyses performed in 1963 on three samples containingapproximately 80, 90, and 95 % sulfuric acid. One analyst in each of tenlaboratories performed duplicate determinations and repeated one daylater, for a total of 120 determinations.9Practice E 180 was used indeveloping the
37、se precision estimates.16.2 Since there is no accepted reference material fordetermining the bias for measuring the total acidity of sulfuricacid, the bias of this test method has not been determined.BAUM GRAVITY17. Scope17.1 This test method covers the determination of theBaum gravity of concentrat
38、ed sulfuric acid by means of aglass hydrometer in the range from 57 to 66.2 Baum. TheBaum gravity is determined at 15.5C (60F). This testmethod is not applicable to readings above 66.2 Baum gravityunits.18. Definition18.1 Baum Gravitya unit of density based on specificgravity and defined by the foll
39、owing equation:Baum gravity 5 145 2 145/sp gr# at 15.5/15.5C 60/60F! (3)19. Summary of Test Method19.1 A sample of sulfuric acid is placed in a hydrometercylinder and when the temperature is constant, the Baumgravity is read from the glass hydrometer.20. Significance and Use20.1 The Baum gravity is
40、used to classify various grades ofsulfuric acid. This test method is not applicable for accuratedeterminations of the concentration of sulfuric acid.9Details of the interlaboratory study are available from ASTM InternationalHeadquarters. Request RR: E15 - 1047.E 223 96 (2002)e1321. Apparatus21.1 Hyd
41、rometer,10streamline or torpedo design, precisiongrade for liquids heavier than water in ranges from 57 to 62B and 63 to 67 B. The total length shall be approximately 12in. (305 mm) divided to 0.05 B over a 6-in. (152-mm)(approximate) scale and standardized at 15.5/15.5C (60/60F)with a tolerance of
42、0.05 B throughout. The modulus is asfollows:B 5 145 2 145/sp gr# at 15.5/15.5C 60/60F! (4)Each of the hydrometers shall show on the scale themodulus.21.2 Thermometer, having a range from 2 to + 80C (30to 180F) and conforming to the requirements for Thermom-eter 15C (15F) as prescribed in Specificati
43、on E 1.21.3 Cylinder, Hydrometer, glass, with or without lip, diam-eter 38 to 40 mm, height 325 to 375 mm.22. Temperature of Test22.1 Baum gravity shall be determined at 15.5 6 0.3C (606 0.5F).23. Procedure23.1 Rinse a clean hydrometer cylinder with the sample tobe tested, add the sample, and adjust
44、 the temperature to 15.5 60.3C (60 6 0.5F). Place the cylinder in a vertical position ina location free of air currents. Insert the hydrometer in thesample. Push it down about 3 mm below the level at which itwill float and release it. Read the hydrometer when it has cometo rest, floating freely, and
45、 the temperature is 15.5C (60F).The correct reading is that point on the hydrometer scale atwhich the surface of the liquid cuts the scale. Determine thispoint by placing the eye slightly below the level of the liquidand slowly raising it until the surface, first seen as a distortedellipse, appears
46、to become a straight line cutting the hydrom-eter scale. Record as Baum gravity.24. Calculation24.1 Calculate the specific gravity for later calculations inaccordance with the following equation:sp gr 5145145 2 Be(5)25. Report25.1 Report the Baum gravity to the nearest 0.01 unit.26. Precision and Bi
47、as26.1 The following criteria should be used for judging theacceptibility of results (see Note 6):26.1.1 Repeatability (Single Analyst)The standard devia-tion for a single determination has been estimated to be 0.018unit absolute at 48 df. The 95 % limit for the differencebetween two such runs is 0.
48、05 unit absolute.26.1.2 Laboratory Precision (Within-Laboratory, Between-Days Variability), Formerly Called RepeatabilityThe stan-dard deviation of results (each the average of duplicates),obtained by the same analyst on different days, has beenestimated to be 0.016 unit absolute at 24 df. The 95 %
49、limit forthe difference between two such averages is 0.045 unit abso-lute.26.1.3 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates), obtained byanalysts in different laboratories, has been estimated to be0.063 unit absolute at 7 df. The 95 % limit for the differencebetween two such averages is 0.18 unit absolute.NOTE 6These precision estimates are based on an interlaboratorystudy of analyses performed in 1963 on three samples having Baumgravities of approximately 61,
