Tiêu chuẩn iso 13312 2017

© ISO 2017 Iron ores — Determination of potassium — Flame atomic absorption spectrometric method Minerais de fer — Dosage du potassium — Méthode par spectrométrie d’absorption atomique dans la flamme[.]

Iron ores — Determination of

Mine ais de fe — Dosage du p tassium— Méth de p r

spectrométrie d’a sorption atomique da s la flamme

T ir d edition

2 17-0

Reference n mb r

ISO 1 3 2:2 17(E)

COPYRIGHT PROTECTED DOCUMENT

© ISO 2017, P blshed in Sw itz rlan

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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 2

6 A pparatus 2

7 S mpl n and samples 4

7.1 L b ratory sample

4 7.2 Pr eparation of pr edried tes samples 4

8 Proc ed re .4

8.1 Numbe of dete minations 4

8.2 Tes p rtion 4

8.3 Blan tes and che k tes 4

8.4 Dete mination 5

8.4.1 General 5

8.4.2 De omp sition of the tes p rtion 5

8.4.3 Tr eatment of the solution .5

8.4.4 Pr ep ration of the set of calbration solutions 5

8.4.5 A djustment of atomic a sorption spe tromete 6

8.4.6 Atomic a sorption measur ement 6

9 Ex pres io of r esults 6

9.1 Calculation of mas fraction of p tas ium 6

9.2 General tr eatment of r esult 7

9.2.1 Repeatabi ty an pe mis ible toleranc 7

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 8

9.2.5 C lculation of final r esult 9

9.3 Ox ide factor 9

10 Test rep r t 9

A nne x A (normative) Flowshe t of the pr oc edure 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

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

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 Te h ical C mmitt ee ISO/TC 1 2, Iro or a d dir c t r duc ed iro ,

Subcommitt ee SC2, Chemic al a alys i s

This third edition canc ls an r plac s the se on edition (ISO 1 3 2:2 0 ), of w hich it cons itut es a

minor r vision with the folowing chang es:

— in 7.2, a new sent enc t o make r fe enc t o ISO 2 9 has be n inclu ed;

— in 9.2.4, F ormula (7)an the r lev nt desc iptions ha e be n modif ied t o harmoniz this subcla use

ac os al Int ernational Stan ards for w hich ISO/TC1 2 SC2 is r sp nsible;

— in 5.4, 5.5, 8.4.2 and 9.2.1, the fo tnot es ha e be n mo ed t o the a pro riat e plac

Iron ores — Determination ofpotassium — Flame atomic

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 document to establsh appro riate he lth and safety practices

and determine the applcabiity of re ulatory lmitations prior to use

This document spe if ies a flame at omic a sorption spe trometric method for the det ermination ofthe

mas fraction of p tas ium in iron or s

This method isa plca le t o mas fractions of p tas ium betwe n 0,0 2 5% an 0,5 % 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 folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 648, L b rator y glas swar — Sin le-v lume pipet es

ISO 1 42, L b rator y glas swar — One -mark v lumetric flask s

ISO 2 9 , Iro or s — Dete min tio o h gros c opic moi s tur in a aly tic al s amples — Grav imetric, Karl

Fi s che a d mas s-os s meth ds

ISO 3 8 , Iro or s — S mpln a d s ample pr p ratio proc edur s

ISO 3 9 , Wate fr a aly tic al la orator y use — S ec ific atio a d tes t meth ds

ISO 7764, Iro or s — Prep ratio o pr dried tes t s amples fr chemic al a alys i s

ISO 1 3 3, Iro or a d dir c t r duc ed iro — Voc ab lary

3 Terms and definitions

F or the purposes of this document, the t erms an def initions given in ISO 1 3 3 a ply

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

The t es p rtion is de omp sed b tr atment with hydrochloric acid an hydrofluoric acid, folowed b

ev p ration t o drynes The r sid e is wett ed an the ev poration is r peat ed with a new portion of

hydrochloric acid The r sid e is dis olved with hydrochloric acid folowed b a pro riat e diution The

solution is aspirat ed int o the air/ c ty lene flame of theat omic a sorption a paratus

The a sorb nc v lue o tained for p tas ium is measur d in comp rison with those o tained from

calbration solutions

During the analy sis, use only r ag ent of r co niz d analytical grade an only wat er that comples with

Grade 2 of ISO 3 9

R eag ent ar t o besele t ed or purif ied for the lowes pos ible blank v lue

5.1 Hy rochloric acid, ρ 1,1 g /ml to 1,1 g /ml

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

5.3 Hy rochloric acid, ρ 1,1 g /ml to 1,1 g /ml, diuted 1 + 2

5.4 Backg round solution

Dis olve 43 g of high-purity iron o ide p wde in 5 0 ml of hydrochloric acid (5.1) Alow t o co l an

diut e with wat er t o 1 0 0 ml

Inst ead of iron o ide, the use of metal c iron with a suita le o idant ispe mitt ed The alkal cont ent of

the o idant shal be low

5.5 Potas ium, s andar d solution, 2 µg K/ml

Pulve iz a out 3 g of high-purity p tas ium chloride in an a at e mortar, dry in an oven at 1 5 °C t o

1 0 °C for 2 h, an al ow t o co l t o ro m t empe atur in a desic at or Dis olve 1, 90 g in wat er, di ut e

with wat er t o 100 ml in a volumetric flask an mix

Trans e 1 ,0 ml of this solution t o a 5 0 ml volumetric flask, di ut e with wat er t o v lume an mix

NOTE Glas eq ipment can b used

St or this s an ard solution in a plas ic b t le

1 ml of this s an ard solution contains 2 µg of p tas ium

6 A pparatus

Ordinary la orat ory eq ipment, inclu ing one-mark pipett es an one-mark v lumetric flaskscomplying

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

6.1 Pol ytetrafluoroethylene (PTF ) be ker s, of ca acity 1 0 ml, pr ovided w ith P FE co e s

6.2 PTF -c oated mag netic stirr ing bar

6.3 PTF dig estio bomb

6.4 Plastic pipetes

6.5 Plastic v lumetr ic flasks and storag e bot les

6.6 Mag netic stir rin hotplates

NOTE Platin m ves els can b used inst ead of P F b aker

Ex cept w he e s at ed, glas eq ipment should be avoided, as it could contaminat e the solutions.

To o tain r la le v lues, the eq ipment should be cleaned and che ked as folows

a) Rinse al volumetric war , inclu ing the pipett esused for pr p ring the calbration solutions, with

diut e hydrochloric acid (5.3)befor use Che k the calbration r gularly or as ne ded

b) Clean PTFE ves elsan s ir ing b rs b s ir ing with 5 ml of diut e hydrochloric acid (5.3) an b

heating for 1 min Discard the rinsings an cond ct a blank t es in each ves el in turn, ex ctly as

spe ified in 8.3 If any a sorb nc v lue is a o e the lmit spe if ied in 8.3, the cleaning proc d r

should be r peat ed or acid r ag ent of a highe purity should be used A t no s ag e should the

s ir ing b rs be han led with the fing ers

c) Platin m ves els, ex clusively used for potas ium analy sis ac ording t o this document, can be

cleaned b the same method as the P FE ves els [se b)] Othe wise, they should be pr -cleaned b

fusion with lthium t etra orat e or l thium b rat e, u ti the a sorb nc r adingsfal t o those for the

l thium salt alone

d) Rinse st orag e b t les with diut e hydrochloric acid (5.3) befor use

6.7 Atomic absorptio spectrometer

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

air/ cety lene flame to av id pos ible ex losio hazards We r tinted safety glas es w henever

the burne is in o eratio

The at omic a sorption spe tromet er shal me t he folowing c it eria

a) Minimum sensitivity:The a sorb nc of themos conc ntrat ed calbration solution ( e 8.4.4) shal

be at leas 0,2

b) Gra h lnearity: The slo e of the calbration gra h co e ing the t op 2 % of the conc ntration rang e

(ex r s ed as a chang e in a sorb nc ) shal not be les than 0,7 of the v lue ofthe 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: Thes an ard deviation of the a sorbanc 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 petitivemeasur ment , shal be les than 1,5 % an 0,5 %, r spe tively, of the mean v lue of the

a sorb nc of the mos conc ntrat ed cal bration 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 wil vary with e ch instrument The folowing parameter were suc es ful y

used in several la orat ories an they can b used as guidelines S lutions were aspirated into an air/acety lene

flame of a premix burner

— hol ow cathode lamp, mA 1

— acetylene flow-rate, l/min 2

In sy st ems where the values shown for g s flow-rates do not ap ly, the ratio of the g s flow-rates can stil b a

useful guideline

7 Sampl ng and samples

7.1 Laborator y sample

F or analy sis, use a la orat ory sample of − 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 − 6 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 pr edr ied test samples

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

such a manne that it is r 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

F or or s ha ing signif icant cont ent of combined wat er or o idiza le comp u ds, an air-eq i ibrat ed

t es sampleshal be pr p r d in ac ordanc with ISO 2 96

8 Proc edure

8.1 Number of determinations

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

t es sample

NOTE The e pres ion “in epen ently” me ns that the secon an an subseq ent result are not afect ed

by the previous result (s) For the particular analytical method, this con ition implies that he repetition of the

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

either case, ap ropriate recalibration

8.2 Test por tion

Taking seve al inc ement , weigh, t o near s 0,0 0 2 g, 0,2 g t o 0,5 g (depen ing on the p tas ium

conc ntration)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

Befor proc eding t o the tr atment of t es p rtions, ensur that the cleaning proc d r s cond ct ed

in 6.6 ( e ls it ems), t og ethe with the q al ty of the r ag ent being used, ha e prod c d a blank t es

v lue for the p tas ium det ermination not gr at er than the eq iv lent of 0,0 2 % (mas fraction)

p tas ium in the or

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

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

t es sampleof thec rtif ied r fe enc mat erial shal be pr p r d as spe if ied in 7.2

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 an the r ag ent 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

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 be ome ne es ary Whe ea c rtif ied r fe enc mat erial is not

a ai a le, a r fe enc mat erial ma be used ( e 9.2.4)

8.4 Determination

8.4.1 General

To pr vent contamination d ring analy sis, the folowing pr cautions shal be taken:

a) f ing er contact with sample, solutions an s ir ing b rs shal be a oided;

b) mouth suction of pipett es shal not be pe mitt ed

8.4.2 Dec ompositio of the test portion

Trans e the t es p rtion ( e 8.2) t o a 1 0 ml PTFE beaker (6.1) S e Not e in 6.6

Moist en it with a few dro sof wat er, then ad 1 ml of hydrochloric acid (5.1) an 1 ml of hydrofluoric

acid (5.2) Ad a PTFE-co t ed ma netic s ir ing b r (6.2) an co e with a P FE cover Adjus the

t empe atur of the ma netic s ir ing hotplat e (6.6) so that a t empe atur of a out 9 °C wi l be

maintained in wat er in a co e ed PTFE beaker Heat, with s ir ing, for 45 min or u ti no furthe

dis olution of the t es portion oc urs R emo e the co e , st op the s ir e , lea ing the b r in the solution,

an ev porat e t o drynes A dd 5 ml of hydrochloric acid (5.1) an ev p rat e a ain t o drynes Dis olve

the salt in 5 ml of hydrochloric acid (5.1) and 40 ml of wat er, an trans e t o a 1 0 ml one-mark plas ic

v lumetric flask (6.5) Diut e t o v lume with wat er an mix

NOTE If an signif icant amou t of resid e remains, con uct the dig stion proces in a stir ed P F dig stion

b mb (6.3) for 45 min at 160°C

8.4.3 Tr eatment of the solution

If the conc ntration of p tas ium is t oo high, it is ne es ary t o di ut e the t es solution Trans e , using

a plas ic pipett e (6.4), y ml of the t es solution t o a 1 0 ml one-mark plas ic v lumetric flask, ad

0,1 × (1 0 − y) ml of the b ckgrou d solution (5.4), di ut e with wat er t o v lume an mix ( e Ta le 1)

A di ut ed t es solution shal be measur d t og ethe with a diut ed blan t es solution, containing the

same amou t of b ckgroun solution as the t es solution Pr p r the di ut ed blank t es solution as

folow s: pipett e y ml of the blan t es solution int o a 1 0 ml one-mark plas ic v lumetric flask, ad

0,1 × (1 0 − y) ml of the b ckgrou d solution, diut e t o volume with wat er an mix

Table 1 — Diution guide for test solution

Potas ium mas -fraction

rang e

%

Alquot from 1 0 ml

y

8.4.4 Pr eparatio of the set of calbr atio solutio s

From the p tas ium s an ard solution (5.5), pr p r calbration solutions as folow s

Using plas ic pipett es, trans e 0 ml;2,0 ml; 5,0 ml;1 ,0 ml; 1 ,0 ml of p tas ium s an ard solution (5.5),

r spe tively, t o 1 0 ml one-mark plas ic v lumetric flasks A dd, using a plas ic pipett e, 1 ml of the

b ckgrou d solution (5.4) t o each, diut e with wat er t o v lume an mix These calbration solutions

co e the conc ntration rang e 0 µg K /ml t o 3 µg K / ml and contain 3 00 µg F e / ml

St or the calbration solutions in plas ic b t les

8.4.5 Adjustment of atomic absorption spectrometer

Optimiz the r sp nse of theins rument as spe ified in 6.7 S t the wavelength of p tas ium (766,5 nm)

t o o tain minimum a sorb nc Aft er 1 min pr heating of the burne , adjus the fuel flow an burne

p sition t o o tain ma imum a sorb nc , w hie aspirating the mos conc ntrat ed cal bration solution

( e 8.4.4) Aspirat e wat er an the calbration solution t o es a lsh 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

8.4.6 Atomic absorptio me sur ements

Aspirat e the calbration an t es solutions or diut ed t es solutions in orde of inc easing a sorption,

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

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

diut ed t es solutions at the pro e p int in the calbration se ies an r cord their r adings Aspirat e

wat er betwe n each calbration an t es solution R epeat the measur ment at leas twic

Obtain the net a sorb nc of each cal bration solution b subtracting the a e ag e a sorb nc of the

z ro calbration solution In a simi ar man e , o tain the net a sorb nc of the t es solution or diut ed

t es solution b subtracting the a sorb nc of the cor esp n ing blank t es solution

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

the conc ntration, in mic o rams of potas ium pe mi i itr ( he t es solution or, if diut ed, the diut ed

t es solution is the final t es solution)

Conve t he net a sorb nc of the f inal t es solution t o mic o rams of potas ium pe mi l ltr b means

of the calbration gra h

W ith conc ntration r adings, the calculation should be made from a sorb nc s t o pe mit che king of

the gra h ’ s lnearity an the blank t es v lue

9 Ex pres ion of results

9.1 Calculation of mas fraction ofpotas ium

The mas fraction of potas ium, ex r s ed asa pe c ntag e, is calculat ed t o f ive de imal plac sfor mas

fractions highe than 0,0 %, an t o six de imal plac s for mas fractions lowe than 0,0 %, using

F ormula (1):

w

m

K

M

=

× ρ

1

1 0

(1)

w he e

w

K

is the mas fraction of p tas ium, ex r s ed as a pe c ntag e, of the t es sample;

ρ

M

is the conc ntration, in mic o rams pe mi l itr , of p tas ium in the f inal t es solution;

m

1

is the mas , in grams, of t es sample r pr sent ed in 1 0 ml of the f inal t es solution (8.4.6),

calculat ed from the fol owing formula:

m

1

1 0

=

×

m being the mas , in grams, of the t es p rtion ( e 8.2);

V being the v lume, in mi i tr s, of the alquot taken in 8.4.3 If no di ution has be n made,

V =1 0