Overview
ISO 3087:2020 specifies an internationally accepted method to determine the moisture content of a lot of iron ore. Applicable to all iron ores (natural or processed), the standard defines sampling prerequisites, test portion sizes, drying and weighing procedures, acceptance criteria and reporting rules for reliable moisture determination used in laboratory and commercial trade contexts.
Key topics and technical requirements
- Scope & sampling: Test samples must be prepared in accordance with ISO 3082. Nominal top size of the moisture test sample shall be ≤ 31.5 mm; larger material must be crushed before testing.
- Test portion mass (minimums):
- Over 22.4 mm up to 31.5 mm: 10 kg
- Over 10.0 mm up to 22.4 mm: 5 kg
- ≤ 10.0 mm: 1 kg
- (A 10 kg test portion may be split into two 5 kg portions and averaged.)
- Apparatus:
- Drying pan with smooth uncontaminated surface, sample layer thickness ≤ 31.5 mm.
- Drying oven capable of maintaining 105 °C ± 5 °C with controlled air circulation (fan).
- Weighing device with readability equivalent to at least 0.01% of the minimum test portion mass and protected from heat.
- Reference drying methods:
- Normal: spread test portion, dry at 105 °C for ≥ 4 h, then re-weigh; continue additional 1 h drying cycles until consecutive mass loss ≤ 0.05% of initial mass.
- Optional for ores with ≥ 8% combined water: dry at 105 °C for ≥ 24 h and weigh.
- Calculation: moisture w (%) for each test portion:
- w = (m1 − m2) / m1 × 100, reported to two decimal places (m1 = initial mass, m2 = dried mass).
- Alternative methods: permitted (e.g., different ovens, higher temperatures up to 140 °C or adjusted drying times) only if validated by ISO 3086 (bias ≤ 0.05% with CI including zero) and ISO 3085 (precision equivalent or better).
- Verification & quality control: routine checks on oven temperature, air circulation, weighing device, and measurement of environmental water (e.g., rainfall, sprinkled water) as applicable.
Practical applications and users
- Who uses it: mining companies, ore processing plants, quality control laboratories, trading houses, inspection bodies and independent laboratories involved in iron ore production, shipping and commercial transactions.
- Why it matters: accurate moisture determination affects mass-based commercial settlements, freight calculations, metallurgical processing performance and material handling/storage decisions.
- Typical uses: routine QC of incoming/outgoing lots, dispute resolution in trade, process control for DR-grade ores, and validation of alternative moisture-testing technologies.
Related standards
- ISO 3082 - Iron ores: sampling and sample preparation
- ISO 3085 - Precision checking methods for sampling and measurement
- ISO 3086 - Bias checking methods for sampling
- ISO 11323 - Vocabulary for iron ore and direct reduced iron
- ISO 2596 - Hygroscopic moisture (for chemical analysis; separate purpose)
Keywords: ISO 3087:2020, moisture content, iron ores, moisture determination, drying at 105 °C, iron ore sampling, test portion mass, reference method, alternative moisture methods.
