1、Designation: D 1394 76 (Reapproved 2003)Standard Test Methods forChemical Analysis of White Titanium Pigments1This standard is issued under the fixed designation D 1394; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number 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.1. Scope1.1 These test methods cover procedures f
3、or the chemicalanalysis of white titanium dioxide pigments.1.2 The analytical procedures appear in the following order:SectionsPreparation of Sample 4Qualitative Analysis 5 and 6Moisture 7Total Titanium:Jones Reductor Method 8-12Aluminum Reduction Method 13-17Aluminum Oxide 18-22Silica 23-291.3 The
4、values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 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-priat
5、e safety and health practices and determine the applica-bility of regulatory limitations prior to use. A specific hazardstatement is given in Section 19.2. Referenced Documents2.1 ASTM Standards:D 280 Test Methods for Hygroscopic Moisture (and OtherMatter Volatile Under the Test Conditions) in Pigme
6、nts2D 1193 Specification for Reagent Water3E 50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated Materials43. Reagents3.1 Purity of ReagentReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that
7、all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lesse
8、ning theaccuracy of the determination.3.2 Unless otherwise indicated, references to water shall beunderstood to mean reagent water conforming to Type IV ofSpecification D 1193.4. Preparation of Sample4.1 The sample shall, in all cases, be thoroughly mixed andcomminuted before taking portions for ana
9、lysis.QUALITATIVE ANALYSIS5. Reagents5.1 Ammonium Hydroxide (sp gr 0.90)Concentrated am-monium hydroxide (NH4OH).5.2 Ammonium Sulfate(NH4)2SO4).5.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).5.4 Hydrogen Peroxide (30 %)Concentrated hydrogenperoxide (H2O2).5.5 Hydrogen Sulfid
10、e (H2S).5.6 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).5.7 Sulfuric Acid (1+19)Carefully mix 1 volume ofH2SO4(sp gr 1.84) with 19 volumes of water.5.8 Tartaric Acid.5.9 Tin or Zinc Metal.6. Procedure6.1 Place about 0.5 g of the sample in a 250-mL glassbeaker,6and add 20 mL of H2SO4(
11、sp gr 1.84) and 7 to8gof(NH4)2SO4. Mix well and boil for a few minutes. The sampleshould go completely into solution; a residue denotes the1These test methods are under the jurisdiction of ASTM Committee D01 onPaints and Related Coatings, Materials, and Applications and are the directresponsibility
12、of Subcommittee D01.31 on Pigment Specifications.Current edition approved Oct. 1, 2003. Published October 2003. Originallyapproved in 1956. Last previous edition approved in 1976 as D 1394 76 (1999).2Annual Book of ASTM Standards, Vol 06.03.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of A
13、STM Standards, Vol 03.05.5Reagent 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
14、 United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.6Borosilicate glass has been found satisfactory for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.presence of
15、silicon dioxide (SiO2) or siliceous matter. Cool thesolution, dilute with 100 mL of water, heat to boiling, let settle,filter, wash with hot H2SO4(1+19) until free of titanium, andtest the residue for lead, etc.6.2 Test the filtrate for calcium, zinc, iron, chromium, etc.,by the regular methods of q
16、ualitative analysis.7For the irondetermination add to a portion of the filtrate5goftartaric acid,render slightly ammoniacal, pass in H2S in excess, and digeston a steam bath. No precipitate after 30 min indicates theabsence of iron, nickel, cobalt, lead, copper, etc. A blackprecipitate readily solub
17、le in dilute HCl denotes iron. Fortitanium, test a small portion of the original filtrate with H2O2(a clear yellow-orange color should result) and another portionwith metallic tin or zinc (a pale blue to violet coloration shouldresult). Negative results should be shown for sulfide, carbon-ate, or ap
18、preciable water-soluble matter.MOISTURE7. Procedure7.1 Determine moisture and other volatile matter in accor-dance with Test Method A of Test Methods D 280.TOTAL TITANIUM BY THE JONES REDUCTORMETHOD8. Scope8.1 This method gives results similar to those obtained withthe Aluminum Reduction Method, Sec
19、tions 13-17.9. Apparatus9.1 Jones Reductor8having a zinc column at least 450 mmin length, and 19 mm in diameter (Fig. 1 and Fig. 2). Thefiltering pad must be tight enough to hold all the particles ofamalgamated zinc resting on it, and may be made of asbestosor, preferably, glass-wool supported by pl
20、atinum gauze or aperforated porcelain plate. Use the least amount (0.1 to 1.0 %)of mercury that will enable satisfactory control of hydrogenevolution, since heavy amalgamation tends to reduce the rateof reaction. Prepare the amalgam by washing 20-mesh zinc for1 min in enough 1 N HCl to cover it, add
21、ing the proper amountof 0.25 M mercuric nitrate or chloride solution, and stirringrapidly for 3 min. Decant the solution and wash the amalgamwith water and store under water to which a few drops of HClhave been added. After using, keep the reductor filled withwater when not in use, in order that bas
22、ic salts will not beformed and clog it.10. Reagents10.1 Ammonium Hydroxide (sp gr 0.90)Concentrated am-monium hydroxide (NH4OH).10.2 Ammonium Sulfate (NH4)2SO4).10.3 Carbon Steel or IronPure iron or plain carbon steel.10.4 Ferric Sulfate Solution (1 mL = 0.02 g Fe)Dissolve20 g of iron or carbon stee
23、l in a slight excess of HCl, oxidizewith approximately 12 mL of HNO3, add about 80 mL ofH2SO4, and heat to dense white fumes. Cool, dilute with waterto 1 L, digest on a steam bath until sulfates are dissolved, andfilter if necessary. To oxidize any ferrous iron that may bepresent, add 0.1 N KMnO4sol
24、ution until a faint pink colorpersists for 5 min. Ferric ammonium sulfate (FeNH4(SO4)212H2O) may also be used to prepare this solution (See 15.4).10.5 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).10.6 Iron or Carbon SteelPure iron or plain carbon steel.10.7 Nitric Acid (sp gr
25、1.42)Concentrated nitric acid(HNO3).10.8 Sodium OxalateNational Institute of Standards andTechnology standard reference material No. 40 of sodiumoxalate (Na2C2O4).10.9 Potassium Permanganate, Standard Reference Mate-rial (0.1 N, 1 mL = 0.008 g TiO2)Dissolve 3.16 g of KMnO4in water and dilute to 1 L.
26、 Let stand 8 to 14 days, siphon off theclear solution (or filter through sintered glass, medium poros-ity), and standardize against the National Bureau of Standardsstandard sample No. 40 of sodium oxalate (Na2C2O4)asfollows: In a 400-mL beaker dissolve 250 to 300 mg Na2C2O4in 250 mL of hot water (80
27、 to 90C) and add 15 mL of H2SO4(1+1). Titrate at once with the KMnO4solution, stirring theliquid vigorously and continuously. The KMnO4solution mustnot be added more rapidly than 10 to 15 mL/min, and the last7Treadwell, F. P., and Hall, William T., Qualitative Analysis, John Wiley add approximately
28、3 mL in excess.20.4 Add 25 mL of EDTA solution. (If the approximatealumina level is known, use the following mathematicalformula for determining the amount of EDTA to add for bestresults: 4 3 %Al2O3+5=mL of 0.02 M EDTA.) Add,dropwise, NH4OH (1+4) until the solution color is just com-pletely changed
29、from red to orange-yellow. Add 10 mL ofbuffer solution and 10 mL of (NH4)2 HPO4solution, boil for5 min, and cool quickly to room temperature in running water.Add 3 drops of xylenol orange indicator solution. If thesolution is purple, yellow-brown, or pink, bring the pH to5.3-5.7 with acetic acid. If
30、 the pH is correct, a pink colorindicates insufficient EDTA; repeat with a new aliquot, startingwith 20.3 and using 50 mL of EDTA solution in 20.4.20.5 Titrate with ZnSO4solution to a yellow-brown or pinkend point. This titration should be performed quickly near theend point by rapidly adding 0.2-mL
31、 increments until the firstcolor change occurs. This color will fade in 5 or 10 s, but is thetrue end point. This step is critical, and failure to observe thefirst color change will result in an incorrect value. The fadingend point does not occur in the second titration. This firsttitration must be
32、greater than 8 mL of ZnSO4solution. ForD 1394 76 (2003)5most accurate work this first titration should require 10 to 15mL of ZnSO4solution.20.6 Add2gofNaF,boil for 2 to 5 min, and cool in runningwater. Titrate the EDTA, released from its aluminum complexby the fluoride, with ZnSO4solution to the sam
33、e end point asin 20.5.21. Calculation21.1 Calculate the aluminum oxide content of the pigmentsample as follows:A 5 Z 3 T!/2 3 S! (1)where:A = percent Al2O3,Z = ZnSO4solution consumed in the second titration, mLT =Al2O3per millilitre of ZnSO4solution, g, andS = specimen used, g.22. Precision22.1 Base
34、d on interlaboratory studies the following criteriashould be used for judging the acceptability of results at the95 % confidence level:22.1.1 RepeatabilityTwo results obtained by the sameoperator on the same sample should be considered suspect ifthey differ by more than 0.22 % relative.22.1.2 Reprod
35、ucibilityTwo results, each the mean of du-plicates obtained by operators in different laboratories shouldbe considered suspect if they differ by more than 0.62 %relative.SILICA23. Scope23.1 This method covers the determination of silica intitanium dioxide (TiO2) pigments.24. Summary of Method24.1 Th
36、e fusion of TiO2pigment with sodium bisulfateleaves only the silica insoluble when the melt is dissolved insulfuric acid. To assure no loss of the silica the sulfuric acid istaken to fuming to dehydrate the silica. The silica content isdetermined by volatilizing the silica in the weighed filtrationr
37、esidue with hydrofluoric acid.25. Apparatus25.1 Erlenmeyer Flask, 250-mL, high silica.25.2 Filter Paper, very fine, ashless, acid washed.25.3 Platinum Crucible and Cover.25.4 Oven, controlled at 120C.25.5 Muffle Furnace, controlled at 1000 6 25C.26. Reagents26.1 Hydrofluoric Acid (sp gr 1.15)Concent
38、rated hydrof-luoric acid (HF).26.2 Sodium Bisulfate(NaHSO4H2O).26.3 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).26.4 Sulfuric Acid (1+1)To 1 volume of water add slowlywith stirring 1 volume of concentrated H2SO4.26.5 Sulfuric Acid (1+9)To 9 volumes of water addslowly with stirring 1
39、volume of concentrated H2SO4.27. Procedure27.1 Transfer1gofpigment weighed to 0.1 mg to a250-mL high silica Erlenmeyer flask containing 10 g ofNaHSO4H2O. If an SiO2content in excess of 5 % is expecteda 0.5-g specimen of pigment may be used to facilitate completefusion with 10 g of NaHSO4H2O.27.2 Hea
40、t over a Meker burner, frequently swirling the flaskuntil decomposition and fusion is complete and clear (exceptfor SiO2). Be careful of overheating at start and of spatteringof the fusion.27.3 Allow to cool and to the cold melt, add 25 mL ofH2SO4(1+1), and heat very carefully and very slowly until
41、thefusion is dissolved. Carefully evaporate to fumes of H2SO4.27.4 Cool and carefully add 150 mL of water. Pour verysmall amounts of water down the sides of the flask withfrequent swirling of the contents to avoid overheating andspattering. Let cool and filter through fine ashless filter paper,using
42、 a 60 gravity funnel.27.5 Wash out all silica from the flask onto the filter paperwith H2SO4(1+9). Police the flask carefully.27.6 Place the filter paper in a platinum crucible and dry ina 120C oven. Heat the partly covered crucible over a bunsenburner. Avoid flaming the filter paper by heating firs
43、t the coverfrom above and then the crucible from below. When the filterpaper is consumed, heat at 1000C for 30 min in a mufflefurnace. Cool in a desiccator and weigh the crucible.27.7 Add 2 drops of H2SO4(1+1) and 5 mL of HF (sp gr1.15). Carefully evaporate to dryness, first on a low heat hotplate t
44、o remove the HF and then over a bunsen burner toremove the H2SO4. Avoid spattering, especially after removalof the HF.27.8 Ignite at 1000C for 10 min. Cool in a desiccator andweigh the crucible again. The difference in weight is silica.28. Calculation28.1 Calculate the silica content as follows:SiO2
45、,%5 W2/S3! 3 100where:W2= SiO2found, g, andS3= specimen used, g.29. Precision29.1 On the basis of an interlaboratory test of this testmethod in which six laboratories tested, in duplicate, fivesamples of titanium dioxide ranging in silica content from 1.5to 8.2 %, within-laboratory standard deviatio
46、n was found to be1.79 % and between-laboratories standard deviation was foundto be 3.44 %. Based on this, the following criteria should beused for judging the precision of results at the 95 % confidencelevel:29.1.1 RepeatabilityTwo results obtained by the sameoperator should be considered suspect if
47、 they differ by morethan 5.1% relative.D 1394 76 (2003)629.1.2 ReproducibilityTwo results, each the mean of du-plicates, obtained by operators in different laboratories shouldbe considered suspect if they differ by more than 9.7 %relative.30. Keywords30.1 aluminum oxide; aluminum reduction; chemical
48、 analy-sis; Jones Reductor; titanium pigmentASTM 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 patent rights, and
49、 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 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, which you may attend. If you feel that you
