1、Designation: C 867 94 (Reapproved 2007)Standard Test Method forSoluble Sulfate in Ceramic Whiteware Clays (PhotometricMethod)1This standard is issued under the fixed designation C 867; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of solublesulfate ions present in water or a filtrate by mean
3、s of aphotometer measuring the turbidity of precipitated bariumsulfate. A method of standardizing the photometer for this testmethod is also given.1.2 Soluble sulfate ions may be removed from clays orclay-water slurries by leaching with water during mixing andsubsequent filter pressing. To remove al
4、l the sulfate ions wouldrequire an impractical number of washings; therefore, this testmethod should be considered a control test and not a quanti-tative analysis for SO4ions.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi
5、lity 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:2C 324 Test Method for Free Moisture in Ceramic Whitew-are ClaysD 1193 Specification for Reagent W
6、ater2.2 American Chemical Society Document:Specification for Reagent Chemicals33. Apparatus3.1 Balance, accurate to 0.0001 g.3.2 High-Speed Mixer.3.3 Filter Press, capable of operating at 690 kPa (100 psi).3.4 Glass Beakers, Erlenmeyer Flasks.3.5 Transfer Pipets.3.6 Spectrophotometer and accessories
7、.3.7 Measuring Spoon, to hold approximately 0.2 g of BaCl2or THQ Cup.3.8 Other usual laboratory equipment, including timers, etc.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specif
8、ications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the regent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2
9、 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean Type IV Grade reagentwater as defined in Specification D 1193.4.3 Barium Chloride (BaCl2H2O) crystals, 20 to 30 mesh.4.4 Salt-Acid Reagent However, it can be prepared from:23.6 ml HCl, 253.0 gm NaCl, 976.4 ml
10、distilled water. Thissolution should be stored in an automatic pipettor for accuratemeasurement.4.5 Glycerine Reagenta mixture of equal volumes of c. p.glycerine and reagent grade water or it may be purchased froma laboratory supply house. This solution should be stored in anautomatic pipettor for a
11、ccurate measurement.4.6 Standard Sulfate Solutiona solution of c. p. sodiumsulfate in reagent grade water at a concentration which containsexactly 100 ppm of sulfate ion.1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct respo
12、nsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved May 1, 2007. Published May 2007. Originallyapproved in 1977. Last previous edition approved in 2001 as C 867 94 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
13、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Chemical Society, 1155 16th Street, NW, Washing-ton, DC 20036.4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical S
14、ociety, 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 United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville
15、,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Standardization of Apparatus5.1 It should be noted that the instrument requires about 30min to warm up. Keep a blank cell in the instrument when asample is not in the holder. For
16、 SO4determination, the filterwavelength should be set at 550 nm.5.2 Using the appropriate pipettes, measure 25 ml of thestandard 100 ppm solution into a 125 ml Erlenmeyer flask.Add5 ml of glycerine reagent and 2.5 ml of salt-acid reagent andstir thoroughly.5.3 Fill a clean transmission cell with the
17、 prepared solution.Be sure to wipe off any droplets of water or solution on theoutside of the cell since this may interfere with the readings.5.4 Insert the cell into the cell holder. Put the 550 nm filterin place and adjust the transmission to read 100.0 percent.5.5 Pour the contents of the cell ba
18、ck into the flask and add1 THQ cupful of BaCl22H2O crystals. Stir thoroughly, makingsure that all crystals are dissolved. Let stand undisturbed for 5min.5.6 After the standing time, quickly fill a clean transmissioncell with the solution and insert it into the cell holder.Again, besure that no water
19、 or solution droplets are adhering to theoutside of the cell. Read percent transmission to the nearest1%.5.7 The standard 100 ppm solution is then made into a seriesof lower concentration solutions in accordance with the fol-lowing dilution chart:ml 100 ppm Sulfate Solution ml H2O ppm Sulfate ion90
20、10 9080 20 8070 30 7060 40 6050 50 5040 60 4030 70 3020 80 2010 90 100 100 05.8 Each solution is to be tested as described above andpercent transmission recorded. The percent transmission is tobe plotted against the ppm sulfate ion concentration and asmooth curve drawn through the points. The result
21、ing chart isto be used in determining the sulfate concentrations of un-known samples of water or filtrate.6. Procedure6.1 The clay sample, if in crude lump form, is to be dried at105C for 24 h, crushed with the mortar and pestle andpulverized with a micro-pulverizer. If air-floated, continue with6.2
22、. If slurry continue with 6.4.6.2 A150-g portion of the ground dried clay is then weighedto the nearest 0.1 g.6.3 Blunge the clay in 350 ml of reagent grade water for 30min at high speed using the Hamilton Beach drink mixer.6.4 Place a fresh piece of Baroid filter paper in the cylinderof a Baroid Fi
23、lter Press. Pour the slurry into the cylinder andtighten the screw on the lid of the cylinder.6.5 Pressure is applied gradually until 100 psi is obtained.Filtrate is caught in an Erlenmeyer flask. To eliminate errorsfrom initial turbidity, the first 5 ml of filtrate is discarded.6.6 Prepare the filt
24、rate for testing by carefully transferringthe desired quantity of filtrate from the Erlenmeyer flask to aclean 30 ml beaker using the appropriate pipette. A25 ml totalsample is used for testing; this sample may be comprised ofbetween 1 ml and 25 ml of filtrate depending on the sulfate ionconcentrati
25、on in the filtrate. If the selected quantities yieldreadings beyond the calibration line, further dilution is re-quired. For example, if one initially prepares a sample of 15 mlof filtrate and 10 ml of DI H2O (25 ml total) and obtains apercent transmission reading below the calibration chart, thenon
26、e should probably use 5 ml of filtrate and 20 ml of DI H2Ofor the next test. One should use very accurate measuringpipettes when transferring any filtrate or water in this test.6.7 Add 5 ml of glycerine solution and 2, 5 ml of salt-acidreagent to the solution in the 30 ml beaker.6.8 Stir thoroughly
27、with a clean glass rod.6.9 Pour the solution into a transmission cell taking care notto create any air bubbles or spill solution on the side of the cell.(Do not touch the unfrosted side of the cell).6.10 Adjust the meter to the 100 % transmission mark onthe scale by using the calibration knob.6.11 P
28、our the contents of the cell back into the beaker andthoroughly rinse and dry the cell. (Do not scratch the cell).6.12 Add 1 THQ cupful of BaCl22H2O crystals to thesolution.6.13 Stir carefully and make sure all the crystals aredissolved.6.14 Allow to stand for five min.6.15 Pour the solution into th
29、e transmission cell and insertthe cell into the holder. Record the percent transmission.7. Report7.1 From the percent transmission readings obtained, usethe following method to calculate soluble sulfate ion concen-tration in ppm.7.2 Percent transmission is converted to ppm SO4of thedilute solution b
30、y using the prepared calibration chart.7.3 The dilution factor is obtained by dividing 17.5 ml bythe number of ml of filtrate used.7.4 The water/solids factor is obtained by dividing the %water by the % solids. For 150-g clay and 350-g H2O, thefactor is 2.33.7.5 Use the following formula to calculat
31、e concentration ofsoluble sulfate:ppm SO4clay dwb!5ppm SO4dilute solution 3 dilution factor!3 water/solids factor. (1)C 867 94 (2007)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standa
32、rd are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif
33、 not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, whi
34、ch you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known 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 ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 867 94 (2007)3
