1、Designation: E 367 03Standard Methods forChemical Analysis of Ferroniobium1This standard is issued under the fixed designation E 367; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthese
2、s indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These methods cover the chemical analysis of ferronio-biun having chemical compositions within the following lim-its:Element Concentration, %Aluminum 2.00
3、 maxCarbon 0.30 maxChromium 2.00 maxCobalt 0.25 maxLead 0.01 maxManganese 3.00 maxNiobium 40.00 to 75.00Phosphorus 0.05 maxSilicon 4.00 maxSulfur 0.03 maxTantalum 7.00 maxTin 0.15 maxTitanium 5.00 maxTungsten 0.50 max1.2 The methods appear in the following order:SectionsNiobium, Tantalum, and Titani
4、um by theIon-Exchange Method 10-311.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of whoever uses this standard to consult andestablish appropriate safety and health practices and deter-mine the applicability of regula
5、tory limitations prior to use.Specific precautionary statements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2A 550 Specification for FerrocolumbiumE 29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 32 Practices for Sampling Ferro
6、alloys and Steel Additivesfor Determination of Chemical CompositionE 50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of MetalsE 60 Practice for Photometric and SpectrophotometricMethods for Chemical Analysis of MetalsE 135 Terminology Relating to Analytical Chemis
7、try forMetals, Ores, and Related MaterialsE 173 Practice for Conducting Interlaboratory StudiesofMethods for Chemical Analysis of MetalsE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 For definition of terms used in this tes
8、t method, refer toTerminology E 135.4. Significance and Use4.1 These methods for the chemical analysis of metals andalloys are primarily intended to test such materials for com-pliance with compositional specifications. It is assumed that allwho use these methods will be trained analysts capable ofp
9、erforming common laboratory procedures skillfully andsafely. It is expected that work will be performed in a properlyequipped laboratory.5. Apparatus, Reagents, and Photometric Practice5.1 Apparatus and reagents required for each determinationare listed in separate sections preceding the procedure.
10、Theapparatus, standard solutions, and other reagents used in morethan one procedure are referred to by number and shallconform to the requirements prescribed in Practices E 50.Photometers shall conform to the requirements prescribed inPractice E 60.5.2 Photometric practice prescribed in these method
11、s shallconform to Practice E 60.6. Safety Precautions6.1 For precautions to be observed in the use of certainreagents in these methods, refer to Practices E 50.1These methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and are the d
12、irectresponsibility of Subcommittee E01.01 on Iron, Steel, and Ferroalloys.Current edition approved June 10, 2003. Published October 2003. Originallyapproved in 1970. Last previous edition approved in 2002 as E 367 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
13、TM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Sampling7.1 For procedure
14、s for sampling the material, and forparticle size of the sample for chemical analysis, refer toPractices E 32.8. Rounding Off Calculated Values8.1 Calculated values shall be rounded off to the desirednumber of places as directed in 3.4 to 3.6 of Practice E 29.9. Interlaboratory Studies9.1 These meth
15、ods have been evaluated in accordance withPractice E 173, unless otherwise noted in the precision and biassection.NIOBIUM, TANTALUM, AND TITANIUM BY THEION-EXCHANGE METHOD10. Scope10.1 These methods cover the determination of niobium,tantalum, and titanium in ferroniobium in concentrations from40 to
16、 75 %, 0.25 to 7 %, and 0.05 to 5.0 %, respectively.11. Summary of Test Method11.1 The sample is dissolved in a hydrochloric-hydrofluoricacid mixture and transferred to an anion-exchange column.Titanium, iron, and other elements are eluted with an ammo-nium chloride-hydrochloric-hydrofluoric acid mi
17、xture. Thiseluate is treated with boric acid and cupferron, and theprecipitate, containing the titanium, is ignited, fused withpotassium hydrogen sulfate, and leached in dilute sulfuric acid.The titanium is oxidized to the yellow pertitanate with hydro-gen peroxide. Photometric measurement is made a
18、t approxi-mately 410 nm. Niobium is removed by eluting with anammonium chloride-hydrofluoric acid mixture. Tantalum isremoved by eluting with an ammonium chloride-ammoniumfluoride solution adjusted to a pH of 5 to 6. The eluates aretreated with the boric acid to complex the fluorides, and eachof the
19、 elements, niobium and tantalum, is precipitated withcupferron, ignited, and weighed as the pentoxide. For tantalumin concentrations below 1 %, zirconium is added as a gathererin the cupferron separation and the tantalum is converted to thepyrogallol complex. Photometric measurement is made atapprox
20、imately 420 nm.12. Interferences12.1 Any bismuth present will appear in the tantalumfraction, but this element is seldom present in concentrationsgreater than 0.005 % in this ferroalloy. Trivalent antimony, ifpresent, is eluted with the titanium and precipitated withcupferron, but it does not interf
21、ere in the photometric methodfor titanium.13. Apparatus13.1 Ion-Exchange ColumnsThe columns must be con-structed of polystyrene tubing approximately 300-mm long and25 mm in inside diameter. A suitable column can be preparedas follows: Insert a waxed, No. 5 rubber stopper containing a5-mm hole into t
22、he bottom of the polystyrene tube. Insert intothe hole and flush with the upper surface of the stopper a150-mm length of polystyrene tubing, having a 5-mm outsidediameter and a 2-mm bore. Attach another 150-mm length ofthis tubing to the smaller tube with an approximately 50-mmlength of polyvinyl tu
23、bing,3and control the flow rate by ahosecock on the polyvinyl tubing.13.1.1 If a number of determinations are to be made, it isconvenient to arrange the columns so that they can be operatedwith a minimum of attention. Plastic columns equipped withfittings of polystyrene have been developed for such
24、anassembly.4Inlet and outlet tubes are polyethylene; flexibleconnections, where necessary, are of polyvinyl tubing. Theflow rate is controlled by hosecocks on these flexible connec-tions. The system must be carefully assembled and checked toavoid possible leakage of the solutions containing hydroflu
25、oricacid.13.2 Plastic WarePolyethylene, polypropylene, or TFE-fluorocarbon.13.2.1 Bottles, 250-mL and 1-L capacity.13.2.2 Graduated Cylinders, 50 and 250-mL capacity.13.2.3 Griffn-Form Beakers and Covers, 250 and 600-mL,and 1-L capacity.14. Reagents14.1 Ammonium Chloride Solution (240 g/L)Dissolve48
26、0 g of ammonium chloride (NH4Cl) in 1600 mL of water bywarming, cool, dilute to 2 L, and mix. Filter, if necessary. Usethis stock solution to prepare the solutions described in14.2-14.4.14.2 Ammonium Chloride-Ammonium Fluoride NeutralMixtureTransfer 600 mL of the NH4Cl solution and 40 mLof HF to a p
27、lastic beaker. Adjust the pH to 5 to 6 with NH4OH(approximately 80 to 85 mL will be required), dilute to 1 L withwater, and mix.NOTE 1This solution must be prepared with care. If the pH is too low,the volume specified will not completely elute the tantalum; if the pH istoo high, tantalum will precip
28、itate in the column, thus leading to error inthe determinations being run as well as the one which follows.14.3 Ammonium Chloride-Hydrochloric-Hydrofluoric AcidMixtureTransfer 240 mL of the NH4Cl solution, 200 mL ofHF and 150 mL of HCl to a plastic bottle. Dilute to 1 L withwater, and mix.14.4 Ammon
29、ium Chloride-Hydrofluoric Acid MixtureTransfer 600 mL of the NH4Cl solution and 40 mL of HF to aplastic bottle. Dilute to 1 L with water, and mix.14.5 Ammonium Nitrate Wash Solution (20 g/L)Dissolve20 g of ammonium nitrate (NH4NO3) in water, and dilute to 1L.14.6 Boric Acid (H3BO3).14.7 Cupferron So
30、lution (60 g/L)Reagent No. 115. Thissolution should be prepared fresh as needed and cooled to 5Cbefore use.14.8 Cupferron Wash SolutionAdd 25 mL of cupferronsolution (14.7) to 975 mL of cold HCl (1 + 9), and mix. Prepareas needed.3Tygon-R tubing has been found satisfactory for this purpose.4Columns
31、available from Ledoux and Co., Inc., Teaneck, NJ, have been foundsatisfactory for this purpose.E36703214.9 Hydrochloric-Hydrofluoric Acid MixtureAdd 250mL of HCl to 300 mL of water, add 200 mL of HF, dilute to 1L with water, and mix.14.10 Hydrogen Peroxide (H2O2), 30 %.14.11 Ion-Exchange ResinStrong
32、ly basic anion-exchangeresin, 200 to 400 mesh, 8 to 10 % divinyl-benzene crosslinkage.5Since the mesh size of the resin may vary consider-ably from lot to lot, air-dry the resin and pass it through a No.270 (53-m) sieve (Note 6). Most of the fines are removedfrom the fraction passing the No. 270 sie
33、ve as follows: Preparea suspension of the resin in HCl (1 + 9). Allow the coarserfraction to settle 10 to 15 min and remove the fines bydecantation. Repeat the process several times until most of thevery fine material has been removed from the suspension.NOTE 2Material retained on the No. 270 sieve
34、may be used for otherpurposes.14.12 Oxalate-Citrate-Sulfuric Acid SolutionDissolve 35g of ammonium oxalate (NH4)2C2O4H2O) and 35 g ofdiammonium hydrogen citrate (NH4)2HC8H5O7)in1LofH2SO4(1 + 39).14.13 Pyrogallol(C6H3-1,2,3-(OH)3).14.14 Sodium Hydroxide Solution (100 g/L)Dissolve 20 gof sodium hydrox
35、ide (NaOH) in 150 mL of water, cool, diluteto 200 mL, and mix. Store in a plastic bottle.14.15 Tantalum, Standard Solution (1 mL = 0.500 mg Ta)Transfer 0.1221 g of tantalum pentoxide (Ta2O5) to a platinumcrucible. Add 2.5 g of potassium hydrogen sulfate (KHSO4)and heat to fuse the oxide. Dissolve th
36、e cooled melt in warmoxalate-citrate-sulfuric acid solution. Transfer to a 200-mLvolumetric flask, cool, dilute to volume with oxalate-citrate-sulfuric acid solution and mix.14.16 Titanium, Standard Solution (1 mL = 0.100 mg Ti)Transfer 0.0834 g of titanium dioxide (TiO2) to a platinumcrucible. Add1
37、gofKHSO4, and heat to fuse the oxide. Cool,and dissolve the melt in 50 mL of warm H2SO4(1 + 9). Cool,transfer to a 500-mL volumetric flask, dilute to volume withH2SO4(1 + 9), and mix.14.17 Zirconium Solution (1 mL = 1 mg Zr)Dissolve 0.5g of zirconium metal in 10 mL of HF in a plastic bottle, anddilu
38、te to 500 mL. An equivalent amount of zirconyl chloridemay be substituted for the zirconium metal.15. Preparation of Ion-Exchange Column15.1 Placea6to10-mm layer of acid-resistant poly(vinylchloride) plastic fiber in the bottom of the column.6Add theresin suspension in small portions to obtain a set
39、tled bed of theresin 150 to 180-mm high. Wash the column with approxi-mately 100 mL of HNO3(1 + 9), and then perform three elutioncycles with alternate additions of 100 mL of HCl (1 + 9) and100 mL of HCl (3 + 1) to remove the remainder of the fines.Finally, wash the column with 200 mL of HCl (1 + 3)
40、 to a levelabout 20 mm above the resin.NOTE 3Resin columns prepared in this way have been used forseveral years; the only maintenance may be to empty and refill the columnwith the resin charge if the flow rate becomes excessively slow due topacking.16. Preparation of Test Solutions16.1 Transfer a 0.
41、5-g sample, weighed to the nearest 0.1 mg,to a 250-mL plastic beaker. Add 40 mL of the HCl-HF acidmixture. Place a plastic cover on the beaker, and heat gently.After the reaction ceases, add HNO3dropwise until thesolution clears (Note 4). Digest on the steam bath for 20 to 30min to remove nitrous ox
42、ide fumes. Rinse the plastic cover andwall of the beaker with the HCl-HF acid mixture, and dilute thesolution to 70 mL with the same acid mixture.NOTE 4The addition of HNO3should be kept to a minimum becauseof its strong replacing power for niobium on the exchange column.Approximately 6 to 8 drops w
43、ill be required.16.2 Transfer 50 mL of HCl-HF acid mixture to the columnin 5 to 10-mL increments. Drain the acid to a level 100 mmabove the resin bed, collecting the eluate in a 600-mL plasticbeaker. Transfer the sample solution in 5 to 10-mL incrementsto the column. As the sample solution moves dow
44、n the column,continue to add the small increments until all of the solutionhas been transferred. Wash the beaker four or five times with4-mL portions of the HCl-HF acid mixture, transferring thewashings to the column. Wash the sides of the column with 10to 15 mL of the HCl-HF acid mixture followed b
45、y severalwashings with the NH4Cl-HCl-HF acid mixture.16.3 Pass a total of 300 mL of the NH4Cl-HCl-HF acidmixture through the column at a flow rate of approximately 100to 125 mL/h. Allow the solution to drain to the top of the resin.Remove the beaker containing the first fraction and reserve thissolu
46、tion for the determination of titanium. Replace the beakerwith another 600-mL plastic beaker.16.4 Wash the sides of the column with four or five portions(a total of about 25 mL) of the NH4Cl-HF acid mixture,allowing the solution to drain to the top of the resin each time.Pass a total of 300 mL of th
47、e NH4Cl-HF acid mixture throughthe column at the flow rate specified in 16.3 (Note 5). Removethe beaker containing the second fraction and reserve thissolution for the determination of niobium. Replace the beakerwith another 600-mL plastic beaker.NOTE 5This point in the preparation of the test solut
48、ions provides aconvenient and satisfactory place to stop, for example overnight, if theelutions otherwise cannot be carried through as a continuous operation.16.5 Wash the sides of the column with five or six 5-mLportions of the NH4Cl-NH4F neutral mixture. Pass a total of350 mL of the NH4Cl-NH4F neu
49、tral mixture through thecolumn, at the flow rate specified in 16.3. Remove the beakercontaining the third fraction and reserve this solution for thedetermination of tantalum as directed in Section 24 or Section29. Prepare the column for the next sample by adding 50 mLof HCl (1 + 3) in 10-mL increments and discarding theeffluents.5Dowex I anion-exchange resin has been found satisfactory. Comparable resultsmay not be obtained with other resins.6Plastic wool available from the Union Carbide Corp., Chemicals Division,Textile Fibers Dept., 900 First Ave., Needha
