Metso Grate Kiln upgrade: DR-grade pellet specs and risks for iron ore engineers
Reviewed by Tom Sullivan

First reported on Australian Mining
30 Second Briefing
Metso is upgrading its Grate Kiln pelletising system to produce higher-quality iron ore pellets tailored for direct reduction (DR) processes in green steelmaking, targeting tighter control of pellet size, strength and metallisation behaviour. The system integrates travelling grate, rotary kiln and annular cooler units, enabling consistent firing temperatures and uniform induration suited to gas-based DR furnaces and potential hydrogen-based reduction. For miners and pellet plants, the move signals growing technical pressure to supply DR-grade pellets with low gangue, high Fe content and predictable reducibility indices.
Technical Brief
- Grate Kiln upgrade centres on optimising heat transfer profiles across travelling grate, rotary kiln and annular cooler.
- Metso is targeting tighter residence-time control in each unit to stabilise pellet thermal histories.
- System configuration allows decoupling of drying, pre-heating, firing and cooling zones for finer process tuning.
- Enhanced burner and airflow management in the rotary kiln aims to minimise temperature gradients across the bed.
- Upgraded process control uses continuous off-gas and temperature feedback to adjust firing and cooling in real time.
- Metso is marketing the Grate Kiln as suitable for both magnetite and hematite pellet feed blends.
- Retrofit potential is emphasised, allowing existing pellet plants to upgrade induration lines without full greenfield builds.
- For other pellet producers, the move signals competitive pressure to reconfigure induration lines around DR-focused process windows.
Our Take
Metso’s push on the Grate Kiln pelletising system for iron ore dovetails with its Metso–Loesche vertical roller mill dry grinding work, signalling a coordinated flowsheet aimed at lower energy and water use from comminution through to DR‑grade pellets.
The Sangdong tungsten mine restart, which also features Metso equipment, shows that the company is already embedded in critical‑minerals projects; leveraging the Grate Kiln in Australia’s iron ore sector could similarly position Metso as a default vendor for low‑carbon pellet feed into emerging green steel hubs.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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