Overview - ISO 11536:2015 (Loss on Ignition, LOI)
ISO 11536:2015 specifies a gravimetric method for determining the loss on ignition (LOI) of fully‑oxidized iron ores, iron ore concentrates and agglomerates. The test quantifies the mass change when a representative test portion is ignited at 1 000 °C, providing a moisture‑corrected LOI value useful in mass balances and oxide calculations for sinter plants and blast furnaces. The method applies to LOI concentrations from 1.0 % to 10.0 % (m/m) and includes requirements for sampling, apparatus, procedure, calculation, precision and reporting.
Key topics and technical requirements
- Scope & limits: Applicable only to fully‑oxidized ores. Not suitable for ores containing metallic iron (direct‑reduced iron), sulfur > 0.2 % (m/m), or partially‑oxidized iron > 1.0 % (m/m).
- Principle: Gravimetric determination - measure mass loss after ignition and correct for hygroscopic moisture to report LOI on a dry basis.
- Test conditions:
- Ignition at 1 000 °C for 60 min ± 10 min in a muffle furnace with adequate air circulation.
- Typical test portion ≈ (2.0 ± 0.2) g (air‑equilibrated, −160 μm laboratory sample).
- Use silica or platinum crucibles preconditioned at 1 000 °C; cool in a desiccator before weighing.
- Balance capability specified to read to appropriate precision (0.1 mg level).
- Moisture correction: Hygroscopic moisture must be determined separately in accordance with ISO 2596; LOI is reported on a dry basis using the prescribed formula.
- Precision & quality control: The standard defines repeatability, between‑laboratory precision, duplicate limits and acceptance criteria; it prescribes independent duplicate determinations and rules for calculating the final analytical result.
- Reporting: Test report must reference ISO 11536 and include sample identification, analytical values, any deviations and pertinent laboratory details.
Applications and users
- Industrial laboratories in mining and mineral processing for iron ore quality control.
- Metallurgical engineers performing material and mass balances in sinter plants and blast furnaces where LOI affects oxide accounting.
- Producers of iron ore concentrates and agglomerates who require standardized LOI results for trade, process control and specification compliance.
- Accreditation and inter‑laboratory comparison programs validating LOI measurement performance.
Related standards
- ISO 2596 - Determination of hygroscopic moisture (required for moisture correction).
- ISO 3082 - Sampling and sample preparation procedures (laboratory sample preparation).
- ISO Guide 35 - Reference materials guidance (for trueness checks).
Keywords: ISO 11536:2015, loss on ignition, LOI, iron ores, gravimetric method, muffle furnace, hygroscopic moisture, ISO 2596, ISO 3082.
