ISO 549:1981

Overview

ISO 549:1981 specifies a gravimetric analytical method to determine the combined water content (water of constitution) in manganese ores. The method separates water by heating a prepared test portion in a stream of dry air and collects the evolved water in absorbent traps. It is intended to be read in conjunction with ISO 4297 and used with appropriate sampling and sample preparation procedures (see ISO 4296/1 and ISO 4296/2).

This standard is aimed at laboratories and quality-control teams within mining, mineral processing and analytical services that require repeatable, comparable moisture measurements for manganese ore characterization.

Key Topics

• Principle: Separation of combined water from the ore by heating a measured test portion in a current of dry air and gravimetric measurement of the water collected in absorbent tubes.

• Apparatus highlights:

  • Quartz (or porcelain) tube approx. 500–600 mm long, 18–20 mm internal diameter with a tapered end (50 mm taper, 1–2 mm bore).
  • Two tubular electric furnaces to heat different tube zones (one to ca. 800–900 °C, one to lower temperatures for the sample zone).
  • Filling materials: mixtures of lead oxide (PbO), lead dioxide (PbO2) and calcined pumice, or alternatively a silver coil in the tube.
  • Absorbent traps filled with magnesium perchlorate [Mg(ClO4)2], and a drying train using a wash bottle with sulfuric acid.

• Sampling and sample preparation: Use procedures described in ISO 4296/1 and ISO 4296/2 to obtain an analytical test portion (typically ground to <100 µm and air-dried under laboratory conditions).

• Typical test portion: 0.5–1 g placed in a platinum or porcelain boat for introduction into the heated zone.

Applications

• Quality control: Determining water of constitution supports ore grading, blending and process control in mining and smelting operations.
• Laboratory analysis: Provides a standardized gravimetric approach for moisture-related characterization used by mineral analysis laboratories.
• Compliance and reporting: Enables consistent reporting of combined water content across suppliers and customers.

Related Standards

• ISO 4296-1: Manganese ores - Sampling - Part 1: Field sampling (guidance for sampling).
• ISO 4296-2: Manganese ores - Sampling - Part 2: Preparation of test samples for analysis.
• ISO 4297: Manganese ores and concentrates - General instructions for chemical analysis methods.

By following ISO 549:1981, laboratories ensure a reproducible gravimetric determination of combined water in manganese ores, improving comparability of moisture data for analytical, commercial and process-control purposes.