BS ISO 04689-2:2017 pdf download

BS ISO 04689-2:2017 pdf download.Iron ores — Determination of sulfur content — Part 2: Combustion/titration method
1 Scope
This document specifies a combustion/titration method for the determination of the sulfur content of iron ores.
This method is applicable to sulfur contents between 0,002 % (mass fraction) and 0,25 % (mass fraction) in natural iron ores, iron ore concentrates, and agglomerates, including sinter products. The results are not affected by the presence of fluoride.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 2596, Iron ores — Determination of hygroscopic moisture in analytical samples — Gravimetric, Karl Fischer and mass-loss methods
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
ISO Guide 35, Reference materials — General and statistical principles for certification
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Principle
The sample is mixed with tungsten(VI) oxide and heated at 1 200 °C in a resistance furnace, using nitrogen as a carrier gas.
5 Reagents
During analysis, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity.
5.1 Magnesium perchlorate, Mg(ClO 4 ) 2 , anhydrous, free flowing, particle size 0,5 mm to 2 mm.
5.2 Tungsten(VI) oxide, (WO 3 ).
5.3 Tin(II) chloride, SnCl 2 ·2H 2 O, particle size 0,5 mm to 2 mm.
5.4 Sodium hydroxide coated silica, particle size 0,5 mm to 2 mm.
5.5 Hydrochloric acid, ρ, 1,16 g/ml to 1,19 g/ml, diluted 1 + 66.
5.6 Potassium iodide, KI, 3 % (mass fraction) solution.
5.7 Starch, 2 % (mass fraction) solution.
Make a suspension of 2,0 g of starch in 10 ml of water, add to 50 ml of boiling water and stir. Cool, dilute to 100 ml and mix.
Prepare this solution immediately prior to use.
5.8 Potassium iodate, KIO 3 , standard volumetric solution, 0,001 042 mol/l.
The potassium iodate should be previously dried for 2 h at 130 °C.
Weigh, to the nearest 0,000 2 g, 0,223 g of dried potassium iodate and dissolve in water. Cool, transfer to a 1 l volumetric flask, dilute to volume and mix.
1 ml of this standard volumetric solution is equivalent to 0,10 mg of sulfur.