SIST ISO 2598-2:1998 PDF

Overview

ISO 2598-2:1992 specifies a reduced molybdosilicate spectrophotometric method for determining silicon (Si) content in iron ores. The method applies to natural iron ores, concentrates and agglomerates (including sinter) with silicon contents from 0.1 % to 5.0 % by mass and is particularly suited to ores containing fluorine (fluorine does not interfere). The procedure converts silicate to a molybdosilicate complex, reduces it to molybdenum blue, and measures absorbance spectrophotometrically at about 600 nm.

Key topics and technical requirements

• Sample preparation and size
  • Predried laboratory sample prepared per ISO sampling/preparation standards; typical test portion ≈ 0.50 g (after predrying).
• Decomposition by fusion
  • Fusion of the test portion with sodium tetraborate or a specified fusion mixture (carbonate + tetraborate) at ~1 100 °C, followed by dissolution in dilute nitric acid.
• Formation and reduction of the molybdosilicate complex
  • Addition of ammonium molybdate to form the molybdosilicate complex and reduction with ascorbic acid to yield molybdenum blue.
• Spectrophotometric measurement
  • Measure absorbance of molybdenum blue at approximately 600 nm; correct readings against a blank/background solution.
• Calibration and quality control
  • Calibration with silicon standard solutions and background solution prepared similarly to samples.
  • Use of blank tests, duplicate determinations, and analyses of certified reference materials for acceptance (repeatability and between-laboratory tolerances are specified).
• Reagents and apparatus
  • Analytical-grade reagents (sodium tetraborate, ammonium molybdate, oxalic and ascorbic acids, dilute nitric and sulfuric acids) and a spectrophotometer suitable for ~600 nm.

Practical applications and users

ISO 2598-2 is intended for:

• Laboratory analysts in mineral analysis and metallurgy performing Si assays on iron ore feedstocks, concentrates and sinter products.
• Mining company QA/QC teams verifying ore chemistry for beneficiation and smelting control.
• Research and regulatory laboratories requiring standardized, comparable silicon determinations.
• Metallurgists evaluating silicon’s effect on blast-furnace charge and product quality.

Benefits include reliable quantification in fluorine-bearing ores, standardized calibration and acceptance criteria, and clear procedural controls for reproducible results.

Related standards

• ISO 2598-1 - Iron ores: Gravimetric methods (Part 1).
• ISO 3081 / ISO 3082 / ISO 3083 - Sampling and sample preparation for iron ores.
• ISO 7764 - Preparation of predried test samples.

Keywords: ISO 2598-2, iron ores, silicon determination, reduced molybdosilicate spectrophotometric method, molybdenum blue, spectrophotometry 600 nm, fusion with sodium tetraborate, ore analysis, QA/QC.