ISO 8833:1989

Overview

ISO 8833:1989 - "Magnetite for use in coal preparation - Test methods" defines standardized sampling and laboratory test methods for magnetite used as the solid phase in dense medium coal preparation. The standard is intended to support purchase/sale agreements, plant design and quality control by providing reproducible procedures for assessing the key properties that determine suitability of magnetite in coal separation processes.

Key topics and requirements

• Scope and material: Methods apply primarily to milled magnetite (largest particles usually < 250 µm) and are also applicable to unmilled material with particle sizes up to about 500 µm.
• Sampling: Prescribes representative sampling techniques (manual increment spear, screw-type auger) and bagged-bulk sampling procedures; recommends gross sample sizes (≈1 kg for consignment samples, 100 g for laboratory samples) and multiple sample splits for purchaser/seller/arbitration.
• Moisture determination: Two accepted approaches - one-stage oven drying or two-stage (free moisture + air-dried moisture); oven drying at 105–110 °C to constant mass. Results reported as percent by mass.
• Particle size distribution: Wet sieve analysis (ISO 2591) down to 38 µm; sub-sieve (< 38 µm) analysis using centrifugal classifiers to avoid magnetic agglomeration. Guidance on preventing/reversing agglomeration (gentle mechanical breakdown) is provided.
• Magnetic and chemical tests:
  • Total magnetics content and relative density measurement methods are specified.
  • Total iron content and iron(II) content are included as chemical parameters to assess magnetite quality.
  • Fundamental magnetic properties (e.g., coercivity, saturation magnetic moment) are acknowledged as relevant but not prescribed - these require specialized apparatus and are usually performed by research institutes or universities. Coercivity may indicate ease of recovery; saturation moment may indicate grain purity.
• Sample preparation: Conforms with ISO 3081 / ISO 3083 sample division and preparation principles to preserve representativeness.

Applications and users

• Applications:
  • Selection and acceptance testing of magnetite for dense medium coal separation.
  • Quality control of incoming magnetite consignments and stockpiles.
  • Input data for design and commissioning of magnetic separators and dense medium plants.
  • Regulatory compliance related to shipping moisture and material stability.
• Primary users:
  • Coal preparation engineers and plant operators
  • Magnetite suppliers and purchasers
  • Metallurgical and analytical laboratories
  • Magnetic separator manufacturers and R&D institutes

Related standards

ISO 8833 references and aligns with other ISO methods, notably:

• ISO 3081 / ISO 3083 (sampling and sample preparation)
• ISO 2591 (test sieving)
• ISO 3310-1 (test sieve requirements)
• ISO 2597 (iron ore iron determination) and ISO 648 (laboratory glassware)

Keywords: ISO 8833, magnetite test methods, coal preparation, sampling, moisture content, particle size distribution, total magnetics, relative density, iron content, magnetic properties.