Overview
ISO 806:2004 specifies a standardized laboratory method for determining mass loss of aluminium oxide (alumina) when heated to 300 °C and subsequently to 1 000 °C. Industry terminology treats the 300 °C mass loss as moisture (MOI) and the additional loss at 1 000 °C as loss on ignition (LOI). The method is suitable for calcined alumina with typical ranges of 0.2–5 % MOI and 0.1–2 % LOI, and it supports both manual and instrumental (thermogravimetric) analyses.
Key topics and technical requirements
- Scope and purpose: Measurement of mass loss at 300 °C (2 h) and at 1 000 °C (2 h) on defined test portions; results reported as percent mass loss.
- Sample handling: Minimize atmospheric exposure; samples may be tested “as‑received” or intentionally “air‑equilibrated” (Annex A). Air‑equilibration improves precision but raises MOI and can alter LOI.
- Apparatus:
- Platinum crucibles with lids (≈25 ml capacity)
- Oven controllable at (300 ± 2) °C with forced air circulation
- Furnace controllable at (1 000 ± 10) °C
- Balance with resolution 0.0001 g
- Vacuum desiccator with specified heat sink and desiccant tray
- Procedure summary:
- Condition crucible (1 000 °C, 15 min), weigh
- Add ~(5 ± 0.5) g test portion, heat at 300 °C for 120 min, cool in desiccator, weigh
- Ignite dried portion at 1 000 °C for 120 min, cool in desiccator, weigh
- Calculate MOI and LOI (dried or undried basis) and report to 0.01 %
- Desiccants & safety: Phosphorus pentoxide, activated alumina, or magnesium perchlorate; warnings about hazards and regeneration of magnesium perchlorate.
- Instrumental methods: Thermogravimetric analysis (TGA) is acceptable if ramp times and atmospheres are validated to match manual method accuracy and precision.
Applications and who uses it
- Quality control in primary aluminium production and smelter-grade alumina manufacturing.
- Laboratories performing compositional certification, incoming raw material inspection, and process control.
- Industrial chemists, QA/QC engineers, laboratory managers, and standards compliance officers who need reproducible MOI/LOI data for product specification, storage decisions, and process optimization.
- Useful for vendors and purchasers requiring consistent reporting of moisture and volatile content.
Practical notes
- Air exposure rapidly increases apparent MOI and LOI; follow either the as‑received or air‑equilibrated protocol consistently.
- Maintain strict temperature control and weigh immediately after controlled cooling to avoid re‑adsorption.
- Use TGA only after demonstrating equivalence with the manual method (precision data and interlaboratory validation referenced in Clause 9).
Related standards
- ISO 806:2004 prepared by ISO/TC 226 (Materials for the production of primary aluminium)
- Based on AS 2879.1‑2000; precision guidance per AS 2850
- Replaces earlier ISO 806:1976 and ISO 803:1976
Keywords: ISO 806:2004, aluminium oxide, alumina, loss on ignition, LOI, moisture (MOI), 300 °C, 1000 °C, thermogravimetric, as-received, air-equilibrated, test method.