1、Designation:E87811 Designation: E878 12Standard Test Method forDetermination of Titanium in Iron Ores and RelatedMaterials by Diantipyrylmethane UltravioletSpectrophotometry1This standard is issued under the fixed designation E878; the number immediately following the designation indicates the year
2、oforiginal adoption or, in the case of revision, the year 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 titanium in
3、iron ores, concentrates, and agglomerates in the compositionalrange from 0.01 % to 6.0 % titanium.NOTE 1As used in this test method (except as related to the term relative standard deviation), percent or “%” refers to mass fraction (wt/wt) of theform g/100g.1.2 The values stated in SI units are to b
4、e regarded as standard. No other units of measurement are included in this standard.1.3 This test method has been evaluated in accordance with Practice E1601 and Guide E1763. Unless otherwise noted in 13,the lower limit in the scope of each method specifies the lowest analyte content that may be ana
5、lyzed with acceptable error (definedas a nominal 5 % risk of obtaining a 50 % or larger relative difference in results on the same test sample in two laboratories).1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof th
6、e user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE50 Practices forApparatus, Reagents, and Safety Considerations for Chemi
7、calAnalysis of Metals, Ores, and Related MaterialsE135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE877 Practice for Sampling and Sample Preparation of Iron Ores and Related Materials for Determination of ChemicalCompositionE882 Guide for Accountability and Qu
8、ality Control in the Chemical Analysis LaboratoryE1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical MethodE1763 Guide for Interpretation and Use of Results from Interlaboratory Testing of Chemical Analysis Methods3. Terminology3.1 For definitions of t
9、erms used in this test method, refer to Terminology E135.4. Summary of Test Method4.1 The sample is decomposed by treatment with hydrochloric, nitric, and sulfuric acids, or by sintering with sodium peroxide,or by fusion with sodium tetraborate and sodium carbonate. Iron is reduced in an acid medium
10、 with ascorbic acid, the color isdeveloped with diantipyrylmethane, and the absorbance is measured at approximately 385 nm.5. Significance and Use5.1 This test method is intended to be used for compliance with compositional specifications for titanium content. It is assumedthat all who use these pro
11、cedures will be trained analysts capable of performing common laboratory procedures skillfully andsafely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures willbe followed. Appropriate quality control practices must be followed suc
12、h as those described in Guide E882.1This test method is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition appro
13、ved Dec. 15, 2011.Aug. 1, 2012. Published JanuaryAugust 2012. Originally approved in 1982. Last previous edition approved in 20052011 asE87801(2005).E878 11. DOI: 10.1520/E0878-112.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.o
14、rg. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becausei
15、t may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr
16、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Interferences6.1 None of the elements normally found in iron ores interfere.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that
17、 allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.3Other grades may be used, provided it is first ascertained that the reagent is of sufficient high purityto permit its use without lessening the
18、accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toType I or II of Specification D1193. Type III or IV may be used if they effect no measurable change in the blank or sample.7.3 Ascorbic Acid Solutio
19、n (10 g/100 mL) (C6H8O6)Dissolve 10 g of ascorbic acid (C6H8O6) in water and dilute to 100 mL.Prepare fresh as needed.7.4 Diantipyrylmethane Solution (15 g/L) C23H24O2N4H2ODissolve 15 g of the reagent in about 300 mL of water and 30mL of (H2SO4) (1 + 1) and dilute to 1 L with water. If a residue rem
20、ains, filter and store the filtrate in a brown bottle.7.5 Ferric Ammonium Sulfate (100 g/L)Dissolve 100 g of ferric ammonium sulfate Fe2(SO4)3(NH4)2SO4in 800 mL of watercontaining 5 mL of H2SO4(1 + 1) and dilute to 1 L with water.7.6 Potassium Pyrosulfate (K2S2O7).7.7 Sodium Tetraborate (Anhydrous)
21、(Na2B4O7)Dry the commercial sodium tetraborate at 60 C to 70 C, then at 160 C, andfinally calcine at 400 C.7.8 Sodium Tetraborate/Sodium Carbonate (Na2B4O7/Na2CO3) Fusion Mixture Mix 1 part of Na2B4O7and 1 part ofNa2CO3and store in an airtight container.7.9 Standard Titanium Solution :7.9.1 Solution
22、 A (1 mL = 0.1 mg Ti)Transfer 0.1670 g of TiO2(previously calcined at 900 C) to a platinum crucible, add 3gto4gofK2S2O7, cover, and fuse at a temperature of 600 C until a clear melt is obtained. Place the cooled crucible and coverinto a 250-mL beaker, add 50 mL to 60 mL of H2SO4(1 + 9), and heat to
23、dissolve the melt. Wash crucible and cover with H2SO4(1 + 9) and remove, adding the washings to the 250-mL beaker. Transfer the solution of a 1-L volumetric flask, dilute to volumewith H2SO4(1 + 9), and mix.7.9.2 Solution B (1 mL = 0.02 mg Ti)Transfer 50.0 mL of standard titanium Solution A to a 250
24、-mL volumetric flask, diluteto volume with H2SO4(1 + 9), and mix.8. Hazards8.1 For precautions to be observed in this test method, refer to Practices E50.9. Sampling and Sample Preparation9.1 SamplingThe gross sample shall be collected and prepared in accordance with Practice E877.9.2 Sample Prepara
25、tionPulverize the laboratory sample to pass a No. 100 (150-m) sieve.NOTE 2To facilitate decomposition, some ores such as specular hematite require grinding to pass a No. 200 (75-m) sieve.10.4.10. ProcedureNOTE 3If the procedure is based on acid decomposition, use steps in 10.1. If the procedure is b
26、ased on alkaline sintering, use steps in 10.2. If theprocedure is based on alkaline fusion, use steps in 10.3.10.1 Acid Decomposition:10.1.1 Weigh approximately the amount of the test sample specified in the table below into a small weighing bottle previouslydried at 150 C.Ti content, %Mass of testp
27、ortion, gAmount ofH2SO4to be addedin 10.1.3, mLAliquot,mL0.010.1 1.0 20 200.10.3 1.0 20 100.31.0 0.5 10 51.06.0 0.1 10 5Dry the bottle and contents for1hat105Cto110C.Capthebottle and cool to room temperature in a desiccator. Momentarilyrelease the cap to equalize the pressure and weigh the capped bo
28、ttle and sample to the nearest 0.1 mg. Repeat the drying andweighing until there is no further loss of mass. Transfer the test sample to a 250-mL beaker and reweigh the capped bottle to thenearest 0.1 mg. The difference between the two masses is the mass of the test sample taken for analysis.3Reagen
29、t Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
30、 MD.E878 12210.1.2 Carry a reagent blank through all steps of the procedure, starting with 10.1.3.10.1.3 Decomposition of SampleMoisten the test sample with a few milliliters of water, add 30 mL of HCl, cover, and digestbelow the boiling point until no further attack is apparent. Add 5 mL of HNO3and
31、 10 mL to 20 mL of H2SO4(see amountsspecified in 10.1.1) evaporate slowly to fumes of H2SO4, then heat strongly for 10 min. Allow the solution to cool, add slowly 50mL of water and 20 mL of HCl, and warm until soluble salts are in solution.10.1.4 Filter on a fine-textured filter paper and collect th
32、e filtrate in a 250-mL beaker. Transfer the residue quantitatively to thefilter paper and wash the filter paper two or three times with hot dilute H2SO4(2 + 98) and two or three times with hot water.Reserve the filtrate.10.1.5 Treatment of Insoluble Matter Ignite the paper and residue in a platinum
33、crucible. Cool, moisten with several dropsof water, add 3 drops or 4 drops of dilute H2SO4(1 + 1) and 10 mL of HF. Evaporate slowly to expel silica and excess of H2SO4.Cool, add to the residue about2gofpotassium pyrosulfate, cover the crucible, and fuse over a burner (approximately 500 C)until a cle
34、ar melt is obtained.10.1.6 Dissolve the cool melt in the reserved filtrate from 10.1.4, remove, and wash the crucible and cover, adding the washingsto the 250-mL beaker. Transfer the solution to a 200-mL volumetric flask, dilute to volume, and mix. Continue in accordance with10.4.10.2 Alkaline Sinte
35、ring Decomposition:10.2.1 Transfer a sample weight in accordance with the table in 10.1.1 to a dried weighing bottle and dry the test sample asdescribed in 10.1.1. Finally transfer the test sample to a 40-mL nickel crucible.10.2.2 Carry a reagent blank through all steps of the procedure starting wit
36、h 10.2.3.10.2.3 Add3gofsodium peroxide and mix using a platinum or nickel spatula. Place the crucible for several minutes at theentrance of a muffle furnace set at 400 C, then place the crucible inside the furnace for about 1 h, for sintering. Remove thecrucible and allow to cool.10.2.4 Transfer the
37、 sintered mass to a 250-mL beaker, cover, and add about 75 mL of water. Wash the crucible once with waterand once with dilute HCl (1 + 4), adding the washings to the beaker. Acidify carefully with 30 mL of concentrated HCl, cover thebeaker, and heat gently until a clear solution is obtained. Add 20
38、mL of dilute H2SO4(1 + 1) and evaporate slowly to fumes ofH2SO4; then heat strongly for 10 min. Allow the solution to cool, add slowly 50 mL of water and 20 mL of concentrated HCl, andwarm until soluble salts are in solution.10.2.5 Continue as described in 10.1.4-10.1.6. Finally carry out spectropho
39、tometric measurements as described in 10.4.10.3 Alkaline Fusion Decomposition :10.3.1 Transfer a test sample weight in accordance with the table in 10.1.1 to a dried weighing bottle and dry the sample portionas described in 10.1.1. Finally transfer the sample to a platinum crucible.10.3.2 Carry a re
40、agent blank through all steps of the procedure starting with 10.3.3.10.3.3 Add5goffusion mixture (7.8) and mix, using a platinum or nickel spatula. Cover the crucible and heat in a mufflefurnace, first gently at 600 C and finally for 10 min at 1000 C to 1050 C. Remove the crucible and swirl cautious
41、ly to causethe cooling melt to solidify in a thin layer on the walls of the crucible.10.3.4 Place the cooled crucible and cover into a 250-mL beaker and add 100 mL of dilute HCl (1 + 4). Heat gently to dissolvethe melt, remove, and wash the crucible, cover, and police adding the washing to the 250-m
42、L beaker.10.3.5 Transfer the solution to a 200-mL volumetric flask, dilute to volume, and mix. Continue in accordance with 10.4.10.4 Preparation of Test Solution for Spectrophotometric MeasurementsTransfer with the help of pipet, an aliquot of the testsolution and the blank solution in accordance wi
43、th the table in 10.1 and transfer into 100-mL volumetric flasks. Add 5 mL of ferricammonium sulfate solution (7.5), and 10 mL of ascorbic acid solution (7.3), and mix. Add 15 mL of dilute HCl (1 + 1) and 30mL of diantipyrylmethane solution (7.4), dilute to volume, and mix. Allow the solution to stan
44、d for at least 10 min.TABLE 1 Grand Means and Precision of Titanium Content of the Test Samples as Determined by the Method Described Using VariousDecomposition MethodsSampleNo.DecompositionMethodsGrand MeanX,%Repeatabilityr, %PermissibleToleranceP, %Standard DeviationWithin-Laboratoriessr,%Between-
45、LaboratoriessL,%76-3 Acid 3.7944 0.0788 0.1706 0.0285 0.058276-3 Sintering 3.8137 0.0848 0.2765 0.0306 0.097476-3 Fusion 3.8122 0.0785 0.1995 0.0283 0.069276-16 Acid 0.0399 0.0023 0.0042 0.0008 0.001476-16 Sintering 0.0402 0.0026 0.0051 0.0009 0.001776-16 Fusion 0.0402 0.0015 0.0034 0.0005 0.001276-
46、17 Acid 0.1602 0.0032 0.0102 0.0012 0.003676-17 Sintering 0.1625 0.0049 0.0133 0.0018 0.004676-17 Fusion 0.1608 0.0055 0.0129 0.0020 0.004476-18 Acid 0.1796 0.0049 0.0081 0.0018 0.002776-18 Sintering . . . . .76-18 Fusion 0.1856 0.0090 0.0159 0.0032 0.0053E878 12310.5 Preparation of Calibration Solu
47、tions for Spectrophotometric MeasurementsTransfer with the help of a pipet (0.0, 1.0,3.0, 5.0, 7.0),7.0, and 10.0 mL) of the titanium standard Solution B (7.9.2) to six 100-mL volumetric flasks, add 5 mL of ferricammonium sulfate solution (7.5) and 10 mL of ascorbic acid solution (7.3), and mix. Add
48、 15 mL of dilute HCl (1 + 1) and 30 mLof diantipyrylmethane solution (7.4), dilute to volume, and mix. Allow the solution to stand for at least 10 min.11. Photometry Spectrophotometry11.1 Adjust the spectrophotometer to the initial setting, using water as the reference solution. While maintaining th
49、is setting,take spectrophotometric readings of the blank, standard, and test solutions, using a light band centered at approximately 385 nmin a 1-cm cell (see Note 2).11.2 Preparation of Calibration Curve Subtract the average absorbance of the 0-mL titanium standard solution from theaverage absorbance of each standard solution and plot the net absorbance against milligrams of titanium per 100 mL of solution.11.3 Photometric RangeThe recommended concentration range is from 0.03 mg to 0.2 mg in 100 mL using a cell depth of1 cm.NOTE 4Cells
