Tiêu chuẩn iso tr 04688 1 2017

© ISO 2017 Iron ores — Determination of aluminium — Part 1 Flame atomic absorption spectrometric method Minerais de fer — Dosage de l’aluminium — Partie 1 Méthode par spectrométrie d’absorption atomiq[.]

Iron ores — Determination of

Part 1:

Mine ais de fe — Dosage de l’aluminium—

Parti e 1: Mé th d e p r spe trométri e d ’a sorpti on atomi que d ans

l a fl amme

Refer ence n mb r

ISO/TR 4 8 -1:2 17(E)

Fir t edition

2 17-04

COPYRIGHT PROTECTED DOCUMENT

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F reword i v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 Principle 1

5 Re g ents 1

6 A pparatus 2

7 S mpl n and samples 3

7.1 L b ratory sample

3 7.2 Pr eparation of pr edried tes samples 3

8 Proc ed re .3

8.1 Numbe of dete minations 3

8.2 Tes p rtion 4

8.3 Blan tes and che k tes 4

8.4 Dete mination 4

8.4.1 De omp sition of the tes p rtion 4

8.4.2 Tr eatment of the r esid e 4

8.4.3 Pr ep ration of the tes solution 4

8.4.4 A djustment of the atomic a sorption spe tr omete 5

8.4.5 Atomic a sorption measur ement 5

9 Ex pres io of r esults 6

9.1 Calculation of mas fraction of aluminium 6

9.2 General tr eatment of r esult 6

9.2.1 Repeatabi ty an pe mis ible toleranc 6

9.2.2 Dete mination of analytical r esult 7

9.2.3 Betwe n-la oratoriesprecision 7

9.2.4 Che k for truenes 7

9.2.5 C lculation of final r esult 8

9.3 Ox ide factor 9

10 Test rep r t 9

A nne x A (informative)Flowshe t of the pr oc ed re for the ac c eptanc e of anal ytical values for test samples 10

A nne x B (informative)Deri vation of r epe tabiity and permis ible toleranc e for mula 11

A nne x C (informative) Pr ecisio data o tained by inter national anal ytical tr ials 12

Biblog raphy 13

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b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a lshed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the v lu tary natur of s an ards, the meaning of ISO spe if ic t erms an

ex r s ions r lat ed t o conformity as es ment, as wel as information a out ISO’ s adhe enc t o the

World Trade Org nization (WTO) principles in the Te hnical Bar ie s t o Trade (TBT) se the folowing

URL: www iso org iso / for word html

This document was pr p r d b ISO/TC 1 2, Iro or a d dir c t r duc ed iro , Subcommitt ee SC 2,

Chemic al a alys i s

This f irs edition Te h ical R ep rt canc ls an r plac s the se on edition (ISO 46 8-1:2 06), w hich

has be n t echnicaly r vised It has be n conve t ed t o a Te hnical R ep rt as it is no long er suita le for

det ermination of aluminium as a r fe e method

Iron ores — Determination ofaluminium —

Part 1:

WARNING — This d cument may in olve hazardo s materials, o eratio s and equipment This

document d es not p rp rt to ad res al of the safety pro lems as ociated with its use It is the

respo sibi ity of the use of this d cument to establsh appropriate he lth and safety practices

This document desc ibes a flame at omic a sorption spe trometric method for the det ermination of the

mas fraction of aluminium in iron or s

This method is a plca le t o mas fractions of aluminium betwe n 0,1 % an 5,0% in natural iron or s,

iron or conc ntrat es an a glome at es, inclu ing sint er prod ct

2 Normati ve r eferences

The e ar no normative r fe enc s in this document

3 Terms and definitions

No t erms an def initions ar lst ed in this document

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

4 Principle

The t es p rtion is de omposed b tr atment with hydrochloric acid an a smal amount of nitric acid

The mixtur is ev p rat ed t o dehydrat e si ca, folowed b diution and f iltration

The r sid e is ignit ed an si ca is r mo ed b ev poration with hydrofluoric and sulfuric acids The

r sid e is then fused with sodium carbonat e and the co led melt is dis olved in the filtrat e

The solution o tained is aspirat ed int o the flame of an at omic a sorption spe tromet er using a

dinitrog en o ide /ac ty lene burne

The a sorb nc v lues o tained for aluminium ar comp r d with those o tained from the calbration

solutions

During analy sis, use only r ag ent of r co niz d analytical grade and only dis i ed wat er or wat er of

eq iv lent purity

5.1 Sodium car bo ate (Na

2 CO

3 ), an ydr ous

5.2 Hy rochloric acid, ρ 1,1 g /ml.

5.3 Nitric acid, ρ 1,4 g /ml

5.4 Hy rochloric acid, ρ 1,1 g /ml, diuted 1 +9

5.5 Hy rofluor ic acid, ρ 1, 1 g /ml, 40% (mas fr action), or ρ 1,1 5 g /ml, 48% (mas fraction)

5.6 Sulfuric acid, ρ 1,84 g /ml, diuted 1+ 1

5.7 Backg round solution

Dis olve 1 g of high purity iron [minimum purity 9 , 9 % (mas fraction)] of mas fraction of aluminium

les than 0,0 2 %, in 5 ml of hydrochloric acid (5.2) an o idiz b ad ing nitric acid (5.3) dro b dro

Ev porat e u ti a syrup consist ency is o tained A dd 2 ml of hydrochloric acid (5.2) an di ut e t o

2 0 ml with wat er Dis olve 1 g of sodium carb nat e (5.1) in wat er and ad it t o the iron solution

Trans e the solution t o a 1 0 0 ml one-mark v lumetric flask an diut e t o v lume with wat er

5.8 A luminium standar d solutio , 5 0 µg A l/ml

Dis olve 0,5 0 0 g of high purity aluminium [minimum purity 9 , 9 % (mas fraction)] in 2 ml of

hydrochloric acid (5.2) C ol, trans e t o a 1 0 0 ml one-mark volumetric flask, diut e t o v lume with

wat er an mix

5.9 A luminium calbratio solutio s

Trans e 2,0 ml; 5,0 ml; 1 ,0 ml; 2 ,0 ml; 40,0 ml; an 5 ,0 ml p rtions of aluminium s an ard solution

(5.8)t o 2 0 ml v lumetric flasks Diut e t o a out 1 0 ml Ad 6 ml of hydrochloric acid (5.2) an 6 ml of

b ckgrou d solution (5.7) t o each flask Pr p r a z ro aluminium calbration solution b trans e ring

6 ml of the b ckgrou d solution t o a 2 0 ml volumetric flask, an ad 6 ml of hydrochloric acid (5.2)

Diut e al the solutions t o 2 0 ml with wat er and mix (F or an at omic a sorption spe tromet er ha ing

high sensitivity, smale p rtions of the s andard solution ma be used )

6 A pparatus

Ordinary la orat ory a p ratus, inclu ing one-mark pipett es an one-mark v lumetric flasks complying

with the spe if ications of ISO 648 and ISO 1 42, r spe tively, an the folowing

6.1 Platinum cr ucible, of ca acity 3 ml

6.2 Mufle furnac e, ca a le of maintaining a temper atur e of a pr ox imately 1 1 0 °C

6.3 Atomic absor ptio spectrometer, eq ip ed with a dinitr og en o ide/ c tylene burne

WARNING — F olow the manufacturer’s instructions for igniting and extinguishing the

dinitrog en o ide/acety lene flame to av id pos ible ex losio hazards We r tinted safety glas es

w heneve the flame is burning

The at omic a sorption spe tromet er used in this method should me t the folowing c it eria

a) Minimum sensitivity: the a sorb nc of the mos conc ntrat ed aluminium calbration solution

(5.9)should be at leas 0,3

b) Gra h l nearity: the slo e of the calbration gra h co e ing the t op2 % of the conc ntration rang e

(ex r s ed as a chang e in a sorb nc ) should not be les than 0,7 of the v lue of the slo e for the

bott om 2 % of the conc ntration rang e det ermined in the same wa

c) Minimum s a i ity: the s an ard deviation of the a sorb nc of the mos conc ntrat ed calbration

solution an that ofthe z ro calbration solution, each being calculat ed from a sufficient n mbe of

r petitive measur ment , should be les than 1,5 % an 0,5 %, r spe tively, of the mean v lue of

thea sorb nc of the mos conc ntrat ed calbration solution

The use of a s rip-chart r corde an / r digital r adout devic is r commen ed t o ev luat e c it eria a),

b)an c) an for al subseq ent measur ment

NOTE Instrument parameter can vary with e ch instrument T e fol owing parameter were suc es ful y

used in several la oratories an they can b used as guidelines S lutions were aspirated into a dinitro en

o ide /acety lene flame of a premix burner

Aluminium hol ow cathode lamp, mA 2

Dinitro en o ide flow rate, l/min 1 ,8

In sy st ems w he ethe v lues shown a o e for g s flow rat esdo not a ply, the ratio of the g s flow rat es

ma s i be a useful guidelne

7 Sampl ng and samples

7.1 Laboratory sample

F or analy sis, use a la orat ory sample of min s 1 0 µm p rticle siz w hich has be n taken an pr p r d

in ac ordanc with ISO 3 8 In the case of or s ha ing significant cont ent of combined wat er or

o idiza le compou ds, use a p rticle siz of min s 1 0 µm

NOTE A guideline on signif icant contents of combined water an o idiza le compou ds is incorporated in

ISO 77 64

7.2 Preparation of predried test samples

Thoroughly mix the la orat ory sample an , taking multiple inc ement , extract a t es sample in such a

wa that it isr pr sentative of the w hole cont ent of the containe Dry the t es sample at 1 5 °C ± 2°C,

as spe ified in ISO 7764 (This is the pr dried t es sample

8.1 Number of deter minations

Car y out the analy sis at leas in d plcat e in ac ordanc with An ex A, in epen ently, on one pr dried

t es sample

NOTE T e e pres ion “in epen ently” me ns that the secon an an subseq ent result is not afected

by the previous result s) F or this particular analytical method, this con ition implies that the repetition of the

proced re is car ied out either by the same operat or at a diferent ime or by a diferent operat or inclu ing, in

either case, ap ropriat e recalibration

8.2 Test por tion

Taking seve al inc ement , weigh, t o the near s 0,0 0 2 g, a pro imat ely 1 g of the pr dried t es

sample o tained in ac ordanc with 7.2

The t es p rtion should be taken and weighed q ickly t o a oid r a sorption of mois ur

8.3 Blank test and check test

In each ru , one blan t es and one analy sis of a c rtif ied r fe enc mat erial of the same ty e of or

should be car ied out in p ralel with analy sis of the or sample() u de the same con itions A

pr dried t es sample of the c rtif ied r fe enc mat erial should be pr p r d as spe if ied in 7.2

The c rtified r fe enc mat erial should be of the same ty e as the sample t o be analy sed, an the

pro e ties of the two mat erialsshould be suff iciently simi ar t o ensur that, in eithe case, no signif icant

chang es in the analytical proc d r wi l be ome ne es ary

Whe e the analy sis is car ied out on seve al samples at the same time, the blank v lue ma be

r pr sent ed b one t es , pro ided that the proc d r is the same and that the r ag ent used ar from

the same r ag ent b t les

Whe e the analysis is car ied out on seve al samples of the same ty e of or at the same time, the

analytical v lue of one c rtified r fe enc mat erial ma be used

8.4 Deter mination

8.4.1 Dec ompositio of the test por tion

Trans e the t es portion (8.2) t o a 2 0 ml beaker Moist en with a few mi i itr s of wat er, ad 2 ml

of hydrochloric acid (5.2), co e with a wat ch-glas an heat g ently Inc ease the heat and dig es jus

below b i ng, u ti no furthe at ack is a p r nt Ad 2 ml of nitric acid (5.3) an dig es for seve al

min t es R emo e the wat ch-glas an ev porat e the solution t o drynes Heat hesalt on the hot-plat e

at 1 5 °C t o 1 0 °Cfor 3 min A dd 5 ml of hydrochloric acid (5.2), co e the beake with a wat ch-glas ,

an warm for seve al min t es Ad 5 ml of wat er, heat t o b i ing, wash the wat ch-glas an the wals

of the beaker, an f ilt er the solution through a medium-t extur p pe int o a 2 0 ml beake C r fuly

r mo e al ad e ing particles with a rub er-tip ed rod or moist ened f ilt er p pe Wash thr e times

with hydrochloric acid (5.4), then with hot wat er unti the filt er p pe is fr e of iron Trans e the pa e

an r sid e t o a platin m c ucible (6.1) Ev p rat e the filtrat e t o a out 1 0 ml an r tain it

8.4.2 Treatment of the r esidue

Ignit e the p pe an r sid e in the platin m c ucible (6.1) at a low t empe atur (5 0 °C t o 8 0 °C) C ol,

moist en with a few dro s of wat er, ad 3 or 4 dro s of sulfuric acid (5.6) an 1 ml of hydrofluoric acid

(5.5), Ev p rat e slow ly t o ex el si ica an then fume t o r mo e the ex ces sulfuric acid Ignit e at a out

7 0 °C A dd 1,0 g of sodium carb nat e (5.1) t o the r sid e ( e Not e), co e the c ucible, and fuse o e a

burne or in a muf le furnac (6.2) u ti a clear melt is o tained (at a out 1 1 0 °C for 1 min)

NOTE If diff iculties are e perienced with the fusion, 2 g of sodium carb nate (5.1) can b used, with a

doubled volume of hydrochloric acid (5.2) In this case, prepare the b ckgrou d solution (5.7) with doubled

q antities of sodium carb nat e an hydrochloric acid

8.4.3 Preparatio of the test solution

Dis olve the co led melt in the r tained f iltrat e ( e 8.4.1), then r mo e an wash in the c ucible an

co e ( e next para ra h)

If the solution is clou y at this s ag e, in icating the pr senc of subs antial amount of hydroly sed

titanium, it hould be filt er d prior t o the trans e t o the 2 0 ml v lumetric flask

Trans e the solution t o a 2 0 ml one-mark v lumetric flask, diut e t o v lume with wat er and mix Use

this solution ( he t es solution) dir ctly for the at omic a sorption measur ment , if the mas fraction of

aluminium in the t es sample isbetwe n 0,1 % an 2,5 % F or mas fractions of aluminium gr at er than

2,5 %, trans e a 40 ml alq ot t o a 2 0 ml one-mark v lumetric flask ( e next para ra h), ad 5 ml

of b ckgrou d solution (5.7) an 4 ml of hydrochloric acid (5.2) Diut e t o v lume with wat er an mix

(Thissolution is the diut ed t es solution )

F or ins rument ha ing high sensitivity, smal e portions of the t es solution ma be pr fe a le In this

case, the amou t of backgroun solutions (5.7)an hydrochloric acid (5.2) should be adjust ed

Trans e a 40 ml alq ot of blank t es solution t o a 2 0 ml volumetric flask A dd 5 ml ofb ckgrou d

solution (5.7)an 4 ml of hydrochloric acid (5.2) Diut e t o v lume with wat er an mix (This solution is

the di ut ed blank t es solution )( Se next para ra h )

The t es solution should be measur d t og ethe with the blan t es solution, and the diut ed t es solution

with the diut ed blank t es solution

8.4.4 Adjustment of the atomic absorptio spectr ometer

S t the wa elength for aluminium (3 6,2 nm) t o o tain minimum a sorb nc Fit the cor e t burne

for dinitrog en o ide an , in ac ordanc with the man factur r’ s ins ructions, lght the flame Aft er

1 min of pr heating the burne , adjus the fuel flow an burne t o o tain ma imum a sorb nc w hi e

aspirating the calbration solution of highes mas fraction of aluminium (5 9) Then ev luat e the

c it eria in 6.3

Aspirat e wat er an the calbration solution of highes mas fraction of aluminium, t o es a l sh that the

a sorb nc r ading is not drif ing, an then set the r ading for wat er t o z ro a sorb nc

8.4.5 Atomic absor ptio me sur ements

Aspirat e the aluminium calbration solutions (5 9) an t es solutions ( e 8.4.3) in orde ofinc easing

a sorption, s arting with the z ro calbration solution an the blank t es or diut ed blank t es solutions

When a s a le r sp nse is o tained for each solution, r cord the r adings Aspirat e the t es solutions

or diut ed t es solutions at the a pro riat e point in the calbration se ies and r cord the r adings

Aspirat e wat er betwe n each calbration solution and t es solution

R epeat the measur ment at leas twic

If ne es ary, conve t the averag e of the r adings for each calbration solution t o a sorb nc Obtain

the net a sorb nc of each calbration solution b subtracting the a e ag e a sorbanc of the z ro

calbration solution In a simiar man e , o tain the net a sorb nc of the t es solution, or that of the

diut ed t es solution, b subtracting the a sorb nc of the blan t es solution, or that of the diut ed

blank t es solution, r spe tively

Pr p r a cal bration gra h b plot ing the net a sorb nc v lues of the calbration solutions a ains

the mas conc ntration of aluminium, in mic o rams pe mi l itr (The t es solution, or in thecase of a

diution, the diut ed t es solution, is the final t es solution )

Conve t the net a sorb nc v lue of the final t es solution t o mic o rams of aluminium pe mi l itr b

means of the calbration gra h

9 Ex pres ion of results

9.1 Calculation of mas fraction ofaluminium

The mas fraction of aluminium, w

AI

ex r s ed as a pe c ntag e, is calculat ed t o four de imal plac s

using F rmula (1):

w

m

m

A l

A l

A l

=

×

×

=

×

ρ

ρ

2 0

1 0 0

5

(1)

w he e

ρ

l

is the mas conc ntration, in mic o rams pe mi l itr , of aluminium in the final t es solution;

m is the mas , in grams, of sample contained in 2 0 ml of the final t es solution

9.2 General tr eatment of r esults

9.2.1 Repe tabiity and permis ible toleranc e

The pr cision of this analytical method is ex r s ed b the r gr s ion shown in F ormulae (2), (3), (4 )

an (5):

NOTE Ad itional information is given in An ex es B an C

d

=0 0 25

05 42

,

,

(2)

P=0 1 23X

05 38

,

,

(3)

σ

d

=0 0 91

05 42

,

,

σ

L

=0 0 63

061 1

,

,

w he e

R

d

is the in epen ent d plcat e l mit ;

P is the pe mis ible t ole anc between la orat ories;

σ

d

is the in epen ent d plcat e s an ard deviation;

σ

L

is the between-la orat ories s an ard deviation;

X is the mas fraction of aluminium, ex r s ed as a pe c ntag e, in the pr -dried tes sample,

calculat ed as folow s:

— within-la orat ory F ormulae (2) an (4 ):the arithmetic mean of the d plcat e v lues;

— betwe n-la orat ories Form ulae (3) an (5): the arithmetic mean of the final r sult (9.2.3)

of the two la orat ories