Tiêu chuẩn iso 04689 2 2017

© ISO 2017 Iron ores — Determination of sulfur content — Part 2 Combustion/titration method Minerais de fer — Dosage du soufre — Partie 2 Méthode par combustion et titration INTERNATIONAL STANDARD ISO[.]

Iron ores — Determination ofsulfur

Part 2:

Mine ais de fe — Dosage du sour —

Partie 2: Méth de p r comb stion et titration

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F reword i v

Introduction 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 5

7.1 L b ratory sample 5

7.2 Pr eparation of pr edried tes samples 5

8 Proc ed re .5

8.1 Numbe of dete minations 5

8.2 Tes p rtion 5

8.3 Blan tes and che k tes 5

8.4 Dete mination

6 9 Ex pres io of r esults 7

9.1 Calculation of sulfur content 7

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 8

9.2.3 Betwe n-la oratoriesprecision 8

9.2.4 Che k for truenes 8

9.2.5 C lculation of final r esult 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 11

A nne x B (informative)Deri vation of r epe tabiity and permis ible toleranc e eq ations 12

A nne x C (informative) Pr ecisio data o tained by inter national anal ytical tr ial 13

Biblog raphy 14

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 46 9- 2:2 1 ), w hich cons itut es a minor

r vision with the folowing chang es:

— 6.7:f irs l ne, aft er “a pro imat ely inse t “1 g

— 9.2.4: modify F ormula (7) an the r lev nt desc iptions, t o harmoniz this subclause ac os al

s an ardsfor w hich ISO/TC 1 2 SC 2 isr sp nsible

A l s of al p rt in theISO 46 9 se ies can be fou d on the ISO websit e

This document was original y publshed as ISO 46 0:1 86 Unde a polcy of rational zation of the

n mbe ing sy st em used in ISO/TC 1 2, it has be n de ided t o r -designat e this document as ISO 468 - 2

It was furthe de ided t o introd c a combus ion/infrar d method, n mbe ed ISO 46 9-3

When next r vised, ISO 46 9:1 8 wi l be r -designat ed as ISO 46 9-1

Iron ores — Determination ofsulfur content —

Part 2:

WARNING — This document may inv lve 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 ifies a combus ion/titration method for the det ermination of the sulfur cont ent of

iron or s

This method is a plca le t o sulfur cont ent betwe n 0,00 % (mas fraction) and 0,2 % (mas

fraction) in natural iron or s, iron or conc ntrat es, an a glome at es, inclu ing sint er prod ct The

r sult ar not afe t ed b the pr senc of fluoride

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 3 5, L b rator y glas swar — B ur ttes

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

ISO Guide 3 , R efe enc e mate ial s — G ene al a d s tati s tic al princ iples fr c ertific atio

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 sample is mix ed with tu gst en(VI) o ide an heat ed at 1 2 0 °C in a r sis anc furnac , using

nitrog en asa car ie g s

The ev lved sulfur dio ide is a sorbed in diut e hydrochloric acid solution containing s ar h an

p tas ium iodide, an thesolution is titrat ed contin ously d ring ev lution with a s an ard v lumetric

solution of p tas ium iodat e

2, an ydr ous, free flow ing , p rticle siz 0,5 mm to 2 mm

5.2 T ung sten(VI) ox ide, (WO

3)

5.4 Sodium h ydrox ide c oated si ica, p rticle siz 0,5 mm to 2 mm

5.5 Hy rochloric acid, ρ, 1,1 g/ml to 1,1 g /ml, di uted 1 + 66

5.6 Potas ium iodide, KI, 3 % (mas fraction) solution

5.7 Star ch, 2 % (mas fraction) solution

Make a suspension of 2,0 g of s ar h in 1 ml of wat er, add t o 5 ml of b i ng wat er an s ir C ol, di ut e

t o 1 0 ml and mix

Pr p r this solution immediat ely prior t o use

5.8 Potas ium iodate, K IO

3, stan ar d v lumetric solution, 0,0 1 042 mol/l

Thep tas ium iodat e should be pr viously dried for 2 h at 1 0 °C

Weigh, t o the near s 0,00 2 g, 0,2 3 g of dried p tas ium iodat e an dis olve in wat er C ol, trans e

t o a 1 l volumetric flask, diut e t o v lume an mix

1 ml of this s an ard v lumetric solution is eq iv lent t o 0,1 mg of sulfur

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, as wel as the folowing S e Figur 1

6.1 Nitr og en suppl y

6.2 Dr ying tower , containing sodium hydr oxide co ted si ca (5.4) an mag nesium per chlorate (5.1)

6.3 Flow meter, g rad ated fr om 0 to 1l/min

6.4 Resistanc e fur nac e, ca a le of maintaining a temper atur e of 1 2 0 °C ± 2 °C

6.5 Refractor y c ombustio tube, ca a le of w ithstan ing a temperatur e of 1 2 0 °C ± 2 °C

6.6 Refractor y c omb stion b at, with lo se-fitting ld, or a suita le refr actory combus ion b at

ca a le of ac ommodating a p r ous cartridg e, as show n in Fig ure 2 a) or b)r espe tively

The folowing dimensions can be used as guidelnes

6.7 Tin(I ) chlor ide absor ptio tu e, of narrow glas tubing containing a pr ox imately 10 g of sold

tin(I ) chloride (5.3), suita ly plug g ed with ine t wo l to pr event the reag ent being blown into the

a sorption ves el

A U-tube is suita le Whe e ne es ary, this is inse t ed in the train at the exit of the combus ion tube at

p int X in Figur 1

If the sample is k own or thought t o contain chloride, e.g in the form of sodium chloride, chlora atit e,

or sca ol t e, the chlorine formed d ring combus ion of the sample should be r mo ed b p s ing theg s

s r am through sold tin(I ) chloride in a suita le tube or ves el (6.7) prior t o a sorption an titration

If n me ous samples ha ing chloride cont ent > (mas fraction) ar t o be analy sed, it is advisa le t o

det ermine the a sorption ca acity of the tin(I ) chloride in orde t o be a le t o ju g e the mos suita le

int erv l for r ag ent r plac ment In such cases, a larg er a sorption ves el ma be pr fe r d

The tin(I ) chloride a sorption tube should also be f itt ed if the chloride cont ent of the t es sample is

un nown

6.8 C lnder, 1 0 ml, tal form, to hold the a sor bing solution

6.9 Bu bler, multi-hole, to reach to the bottom of thecyln e (6.8)

6.10 Bur et e, conforming to ISO 3 5, g rad ated in divisions of 0,0 ml

F or det ermination of low sulfur cont ent [< ,0 5 % (mas fraction)], alt ernative titration devic s such

as a pist on bur tt e or a suita le mic o-syring e ca a le of del ve ing smal, pr cise alq ot of titrant

ma be used

1 sodium h dr ox ide co ted silica

2 an y r ous mag nesium per chlor ate

7 Sampl ng and samples

7.1 Laboratory 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 predried 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 entir cont ent of the containe Dry the t es sample at

1 5 °C ± 2°C as spe ified in ISO 7764 This isthe 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 sample shal be pr p r d in ac ordanc with ISO 2 96

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 2g, a pro imat ely the mas of thepr dried t es

sample spe if ied in Ta le 1

F or 1 g of sample, the combus ion b at or cartridg e should ac ommodat e the inc eased bulk of sample

plus tu gst en(VI) o ide

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

Table 1 — Mas of test portio

Sulfur cont ent

8.3 Blank test and check test

In each ru , one blank t es an one analysis 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 sample of thec rtified r fe enc mat erial shal be pr p r d as spe ified 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 erials should be sufficiently simi ar t o ensur that in eithe case no significant

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 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

8.4 Deter mination

Plac the t es p rtion in a smal weighing b t le containing 1,0 g of tu gst en(VI) o ide (5.2) and mix

thoroughly

Trans e 8 ml of hydrochloric acid (5.5), 1 ml of p tas ium iodide solution (5.6), an 1 ml of s ar h

solution (5.7) t o the a sorption cy linde (6.8) and plac this in p sition at the en of the combus ion

train Adjus the nitrog en flowrat e t o between 1 0 ml/min an 2 0 ml/ min an titrat e the a sorbing

solution with p tas ium iodat e solution (5.8) u ti the colour of the solution is pale blue Normal y, a

few dro s of the p tas ium iodat e solution (5.8)ar sufficient

Trans e the mixtur of t es portion an tu gst en(VI)o ide t o a r fract ory combus ion b at fitt ed with

a lo se-f it ing ld (6.6)an inse t int o the hot zone of the furnac (6.4) at 1 2 0 °C

Alt ernatively, the mixtur of t es p rtion an tungst en(VI) o ide can be plac d inside a p rous

cartridg e, w hich is plac d in a r fract ory combus ion b at [se Figur 2 b)]

Lea e the b at s an ing in the hot zone for a pro imat ely 1 min an then p s nitrog en at a flowrat e

of 1 0 ml/ min t o 2 0 ml/min through the furnac W ith the nitrog en flowing contin ously, titrat e the

a sorbing solution with p tas ium iodat e solution (5.8), keeping the solution jus blue in colour

Titration should be car ied out d ring the ev lution of sulfur g ses in orde t o pr vent sulfur dio ide

being swept out of solution b the flow of car ie g s It ma be ne es ary t o r d c the g s flow t o

1 0 ml/min w hen titrating samples of high sulfur cont ent A fast er flow rat e of 3 0 ml/min ma be

ne es ary w hen analy sing samples of ve y low sulfur cont ent, t o ensur complet e trans e of ev lved

sulfur g ses int o the a sorbing solution

Contin e t o pas nitrog en through the a p ratus for at leas 5 min or unti the a sorbing solution

r mains pe manently blue, w hicheve inv lvesthe long er time

If the sample contains larg e amou t of combined wat er, a film of mois ur ma a pear on theinside of

the a p ratus This should be complet ely v p riz d befor completion of the t es

F or samples of normal sulfur cont ent, combus ion times of 4 min t o 8 min ar usualy suff icient W ith

samples of high sulfur cont ent howeve , it ma be ne es ary t o inc ease combus ion times t o 1 min or

mor t o ensur complet e extraction of sulfur from the sample

Wash the inside of the bub le (6.9) seve al times b r peat edly r leasing the inlet bu g t o the

combus ion tube (alowing the a sorbant t o flow b ck up the bub le ) an then r placing the bu g t o

r st or the nitrog en flow through the a p ratus Finaly, titrat e the solution t o a pale blue en -p int

an r cord the volume of p tas ium iodat e solution (5.8) used R ecord also the v lume of p tas ium

iodat e solution used in the blank t es

If high blanks oc ur [>the eq iv lent of 0,00 % (mas fraction) in the t es sample ], this ma be d e t o

the pr senc of sulfur comp u ds eithe in the tu gst en(VI) o ide or in the r fract ory b ats /p rous

cartridg es used T ngst en(VI) o ide (5.2) can be pr -tr at ed b heating for 2 h at a t empe atur of

8 0 °C, an the blan in the combus ion bo ts /cartridg es can be r d c d b alowing them t o s an

o e night in a suita le furnac at a t empe atur of 1 2 0 °C an then st oring in a desic at or prior t o

use Such pr -tr atment of tu gst en(VI) o ide an the combus ion b at is also r q ir d if the sulfur

cont ent of the t es sample is les than 0,0 % (mas fraction)