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1、TECHNICAL REPORT IS0 TR 11434 First edition 1992-12-01 Nickel alloys - Determination of niobium and tantalum - Ion exchange method Alliages de nickel - Dosage du niobium et du tantale - Mefhode par change d ions Reference number ISO/TR 11434:1992(E) Copyright International Organization for Standardi
2、zation Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:16:52 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOlTR 11434:1992(E) Foreword IS0 (the International Organization for Standardization) is a worldwide fed
3、eration of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that comm
4、ittee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The main task of technical committees is to
5、prepare International Stan- dards, but in exceptional circumstances a technical committee may propose the publication of a Technical Report of one of the following types: - type 1, when the required support cannot be obtained for the publi- cation of an International Standard, despite repeated effor
6、ts; - type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; - type 3, when a technical committee has collected data of a different kind from that which is normally pu
7、blished as an International Stan- dard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be revi
8、ewed until the data they provide are considered to be no longer valid or useful. ISO/TR 11434, which is a Technical Repot-t of type 1, was prepared by Technical Committee ISO/TC 155, Nickel and nickel alloys, Sub- Committee SC 4, Analysis of nickel alloys. Originally, this ion exchange method for th
9、e determination of niobium and tantalum contents was part of a composite ion exchange procedure which also included determinations of molybdenum, titanium and tung- sten contents. Because of the very complexity of the lengthy composite procedure, it was decided to rewrite the method in the present f
10、orm covering niobium and tantalum only. The interlaboratory precision test- 0 IS0 1992 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the pu
11、blisher. International Organization for Standardization Case Postale 56 l CH-1211 Gen:, Hydrofluoric acid, p20 = I,13 g/ml, 40 % (m/m) WARNING - Hydrofluoric acid is extremely irritating and corrosive to skin and mucous membranes, producing severe skin burns which are slow to heal. In the case of co
12、ntact with skin, wash well with wa- ter and seek medical advice. 4.2 Hydrochloric acid, p20 = I,18 g/ml, diluted 1 +4. 4.3 Nitric acid, pzO = I,41 g/ml, diluted 1 + 4. 4.4 Sulfuric acid, pZO = I,84 g/ml, diluted 1 + 19. 4.5 Anion exchange resin, strongly basic 109 to 200 mesh (8 % cross-linked polys
13、tyrene-divinyl benzene matrix). 4.6 Hydrofluoric acid (5,4 mol/l)-hydrochloric acid (3,0 mol/l), solution. Add 1 200 ml of hydrofluoric acid (4.1) to 1 250 ml of hydrochloric acid (Pan= I,18 g/ml), dilute to 5 litres with water and mix. Prepare and store in a plastics bottle. 1 Copyright Internation
14、al Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:16:52 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOlTR 11434:1992(E) 4.7 Ammonium chloride (4,7 mol/l), stock solution. 4.14
15、 Pyrogalfol, solution. Dissolve 750 g of ammonium chloride in 2 litres of Dissolve 100 g of pyrogallol 1,2,3-trihydroxy- water, filter through a fast filter paper, dilute to benzene, C,H,(OH), in 400 ml of the mixed oxalic- 3 litres and mix. This reagent is used to prepare citric acids solution (4.1
16、3). Dilute to 500 ml with the other reagents. mixed acids solution. 4.8 Ammonium chloride (I,4 rnol/l)-hydrochloric acid (I,4 mol/l)-hydrofiuoric acid (5,4 mol/l), sol- ution. Add 600 ml of the hydrofluoric acid (4.1) to 720 ml of the ammonium chloride stock solution (4.7). Add 310 ml of hydrochlori
17、c acid (ppO = I,18 g/ml). Dilute to 2,5 litres with water and mix. Prepare and store in a plastics bottle. 4.9 Ammonium chloride (2,6 mol/l)-hydrofluoric acid (I,1 mol/l), solution. 4.15 Tantalum, standard reference solution, 0,000 2 g/ml. Transfer 0,048 8 g of pure tantalum pentoxide (Ta,O,) to a s
18、ilica crucible. Add 1 g of potassium pyrosulfate (K,S,O,) and fuse completely. Cool the melt. With constant stirring, dissolve the melt in 75 ml of warm mixed oxalic-citric acids solution (4.13). Cool the solution. Transfer the solution to a 200 ml one-mark volumetric flask, rinsing the beaker with
19、the mixed acids solution (4.13). Dilute to the mark with the mixed acids solution. 4.16 Zirconium sulfate, solution. Add 120 ml of the hydrofluoric acid (4.1) to 1 390 ml of the ammonium chloride stock solution (4.7), dilute to 2,5 litres with water and mix. Prepare and store in a plastics bottle. D
20、issolve 3,90 g of zirconium sulfate in 75 ml of the dilute sulfuric acid (4.4). Transfer the solution to a 100 ml one-mark volumetric flask using the dilute sulfuric acid. Dilute to the mark with the dilute sulfuric acid and mix. 4.10 Ammonium chloride (2,6 mol/l)-ammonium fluoride (I,1 mol/l), solu
21、tion. 5 Apparatus Add 120 ml of the hydrofluoric acid (4.1) to 1 390 ml of the ammonium chloride stock solution (4.7). Using a pH paper, adjust the acidity to pH 5 to 6 using ammonia solution (pZO = 0,88 g/ml) (about 175 ml is required). Cool, di!ute to 2,5 litres with water and mix. Prepare and sto
22、re in a plastics bottle. Ordinary laboratory apparatus, and 5.1 Polytetrafluoroethylene (PTFE) beakers, of ca- pacity 250 ml. 5.2 Plastics beakers, of capacity 600 ml. Poly- 4.11 Cupferron, solution. methylpentene or fluorocarbon polymers have been found to be satisfactory. Dissolve 15 g of cupferro
23、n ammonium N-nitroso- phenylhydroxylarnine, C,H,N(NO).ONH, in water, dilute to 250 ml and mix: Filter through a pulp pad before use. Prepare a fresh solution when required. 5.3 Polyvinylchloride (PVC) wool 5.4 Volumetric flasks, of capacities 50 ml, 100 ml and 200 ml, in accordance with IS0 1042, Cl
24、ass A. 4.12 Cupferron-hydrochloric acid, wash solution. 5.5 Pipette, of capacity 10 ml, in accordance with IS0 648. Class A Add 50 ml of hydrochloric acid (p20 = I,18 g/ml) to 800 ml of water, mix and cool to less than IO C. Add 5 ml of cupferron solution (4.11) and dilute to 1 litre with cold ( 10
25、“C) water. 5.6 Microburette, of capacity IO ml, calibrated in divisions of 0,02 ml in accordance with IS0 385-1, Class A. 4.13 Mixed oxalic-citric acids, solution. 5.7 Molecular absorption spectrometer, suitable for measuring absorbance at 400 nm. With constant stirring, add 25 ml of sulfuric acid (
26、1 = I,84 g/ml) to 950 ml of water. Add 40 g of am- monium oxalate (COONH,),.H,O and 50 g of tri- ammonium citrate (NH,),C,H,O, and warm to dissolve. Cool, dilute to 1 litre with water, mix and filter through a fast filter paper. 5.8 Ion exchange column 5.8.1 The column is made from polyethylene tubi
27、ng with an internal diameter of 25 mm and length of 380 mm. The lower (funnel shaped) end of the col- umn is connected to a polyethylene delivery tube, 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Res
28、ale, 04/24/2007 10:16:52 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOlTR 11434:1992(E) with an internal diameter of 5 mm, fitted with a flow regulating valve (see figure 1). 5.8.2 Transfer approximately 300 g of the resin (4.5) to the 600 ml plastics beaker (5.2). 5.
29、8.3 Add 200 ml of the dilute nitric acid (4.3) to the resin and stir. Allow the resin to settle and decant the nitric acid. Repeat this process four more times. This treatment removes the very fine resin particles. 7 Procedure 7.1 Test portion and preparation of test solution 7.1.1 Weigh, to the nea
30、rest 0,l mg, a test portion of the sample according to table I. Table 1 - Mass of samPIe to be taken 5.8.4 Repeat the washing described in 5.8.3 using five 200 ml volumes of water. Expected niobium and tantalum contents Mass of sample % (m/m) 9 58.5 Repeat the washing described in 5.8.3 using five 2
31、00 ml volumes of the dilute hydrochloric acid (4.2). 5.8.8 Repeat the washing described in 5.8.3 using five 200 ml volumes of the hydrofluoric acid- hydrochloric acid solution (4.6). 5.8.7 Insert a pad of the PVC wool (5.3) in the re- stricted end of the column and pour in sufficient of the resin sl
32、urry to produce a settled column which is 260 rnm long. 5.8.8 Wash the column five times with 20 ml vol- umes of the hydrofluoric acid-hydrochloric acid sol- ution (4.6). Adjust the flow rate to 100 ml/h to 125 ml/h. 58.9 Whilst the bend in the outlet tube will prevent the resin becoming dry by drai
33、nage, the column, when not in use, should be left with the top closed and sufficient solution over the resin bed to prevent drying by evaporation. 6 Sampling and sample preparation 6.1 Sampling and preparation of the laboratory sample shall be carried out by normal agreed pro- cedures or, in the cas
34、e of dispute, according to the relevant International Standard. 6.2 The laboratory sample is norrnally in the form of millings or drillings and no further preparation of the sarnple is necessary. 6.3 If it is suspected that the laboratory sample is contaminated with oil or grease frorn the milling o
35、r drilling process, it shall be cleaned by washing with high purity acetone and dried in air. 6.4 If the laboratory sample contains particles or pieces of widely varying sizes, the test sample should be obtained by riffling. 7.1.2 Transfer the test portion to the 250 ml PTFE beaker (5.1). Dissolve t
36、he sample in a mixture of 10 ml of the hydrofluoric acid (4.1), 50 ml of hydrochloric acid (pZO = I,18 g/ml) and 10 ml of nitric acid (pZO = I,41 g/ml). Apply sufficient heat to initiate and maintain the reaction until dissolution is com- plete. Evaporate the solution just to dryness. Do not bake th
37、e salts. Cool the residue, add 25 ml of the hydrofluoric acid and again evaporate just to dryness. Cool the residue, add 100 ml of the hydrofluoric acid-hydrochloric acid solution (4.6) and heat the mixture gently to dissolve the solids. Cool the solution to room temperature. 7.2 Separation of niobi
38、um and tantalum 7.2.1 Transfer the test solution to the resin bed and pass it through the bed. Collect the eluate in a 1 000 ml plastics beaker. Allow the solution to drain to just above the resin bed. Wash the PTFE beaker with 15 ml to 20 ml of the hydrofluoric acid- hydrochloric acid solution (4.6
39、). Repeat when the previous washings drain to just above the resin bed. Wash the inside walls of the column with a fine jet of the hydrofluoric acid-hydrochloric acid solution. 7.2.2 Wash the resin bed with 300 ml of the hydrofluoric acid-hydrochloric acid solution (4.6) added in 50 ml increments. D
40、iscard the eluate. 7.2.3 Wash the resin bed with 300 ml of the am- monium chloride-hydrochloric acid-hydrofluoric acid solution (4.8) added in 50 ml increments. Discard the eluate. 7.3 Elution of niobium Elute the niobium from the resin bed with 350 ml of the ammonium chloride-hydrofluoric acid solu
41、tion (4.9) and collect the eluate in a 600 ml plastics 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:16:52 MDTNo reproduction or networking permitted without license from IHS -,-,
42、- ISOlTR 11434:1992(E) beaker. Determine the niobium content in this sol- ution as directed in 7.7. 7.4 Elution of tantalum After elution of niobium, elute the tantalum from the resin bed with 350 ml of the ammonium chloride- ammonium fluoride solution (4.10) and collect the eluate in a 600 ml plast
43、ics beaker. Determine the tantalum content in this solution as directed in 7.6 or 7.7. NOTE 1 If only tantalum is to be determined, niobium, if present, must always be eluted from the column before proceeding with the elution of tantalum. 7.5 Regeneration of the resin bed Prepare the resin bed for s
44、ubsequent separations by passing 100 ml of the hydrofluoric acid- hydrochloric acid solution (4.6) through the bed. Discard the eluate. 7.6 Determination of tantalum contents of 0,Ol % (m/m) to 0,3 % (m/m) 7.6.1 Colour development 7.6.1.1 Add 15 g of boric acid (H,BO,) to the eluate obtained in 7.4,
45、 and stir the solution until the acid dissolves. Acidify with 60 ml of hydrochloric acid (pZO= I,18 g/ml) and add I,0 ml of the zirconium sulfate solution (4.16). Mix and cool the solution to 10 “C. 7.6.1.2 Add slowly while stirring constantly, 30 ml of the cupferron solution (4.11). Then add a litt
46、le pa- per pulp, mix, and allow to stand for 15 min. 7.6.1.3 Filter the solution through an ashless pulp pad. Transfer all the particles from the beaker to the pad with the cold cupferron wash solution (4.12). Wash the pad and precipitate five times with 20 ml volumes of the cupferron wash solution.
47、 Remove excess liquid from the pad by suction and transfer the pad and precipitate to a silica crucible. 7.6.1.4 Char the pad without flaming and ignite at 600 “C for 60 min. Cool, add 1 g of potassium pyrosulfate (K,S,O,) and fuse the mixed oxides. Cool the melt. 7.6.1.5 While stirring constantly,
48、dissolve the melt in 40 ml of the warm oxalic-citric acids solution (4.13). Cool the solution. Transfer the solution to a 50 ml one-mark volumetric flask (5.4) using the oxalic-citric solution. Dilute to 50 ml with the oxalic- citric acids solution and mix. 4 7.6.1.6 Using a pipette (5.5), transfer
49、IO,0 ml of the solution to a 50 ml volumetric flask (5.4) containing 25 ml of the pyrogallol solution (4.14). Dilute to 50 ml with the oxalic-citric acids solution (4.13). Mix and allow to stand for 10 min. (This is the test sol- ution .) 7.6.1.7 Dilute 25 ml of the pyrogallol solution (4.14) to 50 ml with the oxalic-citric acids solution (4.13) in a 50 ml volumetric flask (5.4). Mix and allow to stand for 10 min. (This is the com