Overview
ISO/TR 18230:2015 - "Iron ores - Determination of loss on ignition - Non-oxidised ores" defines a gravimetric method to measure loss on ignition (LOI) of non-oxidised iron ores, concentrates, agglomerates and sinters. The method quantifies mass loss when a test portion is ignited at 1 000 °C and is applicable over a LOI range of −3.0 % to 7.0 % (mass fraction). It is intended for in-house quality control and routine laboratory use (not for referee purposes). The Technical Report also provides acceptance criteria, precision guidance and reporting requirements.
Key topics and technical requirements
- Principle: Measure mass loss of a known test portion after heating at 1 000 °C for 60 min and cooling in a desiccator; calculate LOI as percentage of the original sample mass.
- Test portion and sampling:
- Laboratory sample: particle size −100 µm (prepare per ISO 3082).
- Typical test portion: ~2.0 g ± 0.2 g.
- Predried samples may be prepared following ISO 7764.
- Apparatus and consumables:
- Muffle furnace capable of 1 000 °C ± 25 °C with adequate air circulation.
- Silica, porcelain or platinum crucibles (15–25 ml) with lids; crucibles pre-conditioned at 1 000 °C for 60 min.
- Balance with at least 0.1 mg (0.0001 g) readability.
- Vacuum desiccator with dried silica gel (replace daily).
- Procedure essentials:
- Pre-treat crucible, weigh, add test portion, ignite at 1 000 °C for 60 min ± 10 min, cool under vacuum 30 min, reweigh.
- Calculate LOI = (m2 − m3) / (m2 − m1) × 100, where m1 = crucible + lid, m2 = crucible + lid + dry test portion, m3 = after ignition.
- Quality and statistical control:
- At least duplicate independent determinations are required.
- The Report sets repeatability and between‑laboratory precision criteria and provides an acceptance flowsheet (Annex A) and guidance for checking trueness against CRMs.
Applications and users
- Primary uses:
- Sinter plant and blast furnace mass/charge calculations
- Routine quality control of natural iron ores, concentrates, sinters and agglomerates
- Estimation of combined water content (LOI commonly used as proxy)
- Typical users:
- Mine and concentrator laboratories, metallurgical QC labs, process engineers, and technical teams in iron and steel companies.
- Important exclusions:
- Not applicable to processed ores containing metallic iron (direct reduced iron, DRI), ores with sulfur > 0.2 % mass fraction, or internationally traded ores with combined water > 2.5 %.
Related standards
- ISO 3082 - sample preparation / particle size
- ISO 7764 - predrying of samples
- ISO Guide 35 - certification of reference materials (CRM)
Keywords: ISO/TR 18230:2015, loss on ignition, LOI, iron ores, gravimetric method, non-oxidised ores, muffle furnace, quality control.