Ferrexpo pellets · RobSimmons223311 / CC BY-SA 4.0
A specification is an interface
Pellets connect the mine, the pellet plant and the ironmaking operation. A procurement decision therefore needs a shared definition of the intended product and its downstream use. Iron content is one part of that definition; a commercial specification also needs agreed sampling, test methods, limits and responsibilities. Treat the specification as an interface between businesses, not simply a list of laboratory results.
What the operating evidence tells us
A June 2024 article published by Midrex describes the use of different pellet feedstocks at Cleveland-Cliffs’ Toledo HBI plant. It shows why the downstream customer and the intended HBI product matter when assessing feed choices. This is a plant-specific operating account, not evidence that every DR installation can accept the same feed substitution.
Build a qualification dossier
A useful qualification dossier brings together the proposed ore source, pellet production route, available test results and the range of expected variability. Identify which results come from laboratory work, a pilot campaign or sustained industrial production. Keep those evidence levels separate. Ask the receiving plant which tests and acceptance procedures it requires before making a commercial commitment.
Make the trial answer a decision
Before a trial, agree what decision the result will support: approval of a new source, a change in blend, or a change to an operating envelope. Record the baseline and the variables that will be held constant. Define how results will be reviewed and what evidence would trigger further testing. A well-designed trial can produce a useful negative result; a poorly defined trial can leave both buyer and seller with different interpretations.
A practical perspective
The strongest project discussions begin with the intended iron product and work backwards through the feed chain. For pellet producers, EPC teams and technology suppliers, the opportunity is to make these interfaces explicit early enough to influence design. A generic “DR-ready” label is less informative than a documented qualification plan. This article offers a decision framework, not a universal pellet specification.
Follow iron units through the receiving route
A pellet is purchased by mass but used for its recoverable iron and its behaviour in the receiving process. Compare delivered cost per tonne of pellet, delivered cost per tonne of total iron and the expected cost per tonne of usable iron product. These are different measures. The last requires plant-specific assumptions for reduction, handling, melting and losses; it cannot be obtained from an assay alone.
Illustrative purchase comparison
At the same delivered price of $150/t, a pellet with 67% total Fe costs about $224 per tonne of contained Fe; a pellet with 65% Fe costs about $231 per tonne of contained Fe. This arithmetic excludes metallisation, yield losses, gangue treatment, energy, freight differences and commercial penalties. It demonstrates a comparison basis, not an estimate of an actual contract.
Cold strength, reducibility and clustering answer different questions
A pellet can resist a room-temperature compression test yet behave differently as its oxide phases are reduced. Qualification should therefore separate transport survival, reaction behaviour, degradation during reduction and the tendency of particles to adhere under the intended burden and gas conditions. Do not infer all of these from a single strength certificate.
Midrex’s raw-material discussion describes the importance of iron content, gangue and metallurgical performance for DR feed. The appropriate limits and test conditions belong to the receiving operation’s specification. A product marketed as “DR-grade” still requires a defined acceptance dossier for the proposed plant and blend.
| Question | Evidence to request | Limit of the evidence |
|---|---|---|
| Will it survive transport? | Cold physical tests and shipment history | Does not establish strength during reduction. |
| Will it reduce at the required rate? | Relevant reducibility test with gas, temperature and size basis | Does not directly guarantee plant productivity. |
| Will the burden remain stable? | Reduction degradation and clustering assessments | Must represent intended operating conditions and blend. |
| What reaches steelmaking? | Total Fe, metallic Fe, carbon and gangue balance for the intended product | A pellet assay alone does not give final liquid-steel yield. |
Plan a trial that can reject the commercial hypothesis
State the proposed benefit before the trial: lower feed cost, greater supply flexibility or improved downstream performance. Then define the measurements that could disprove it. For example, a lower purchase cost may be offset by a higher reject rate, lower usable output or additional downstream treatment. Set the review rule in advance rather than selecting favourable indicators afterwards.
Use staged qualification: document review, representative laboratory work, an agreed plant trial where appropriate, and review of repeated deliveries. Retain source, lot, blend, test methods and uncertainties. A short successful campaign establishes evidence for that campaign; it does not prove that a wide range of future ore blends will behave identically.
Read the Toledo case as a conditional operating result
The June 2024 Cleveland-Cliffs account published by Midrex describes adapting the Toledo HBI plant’s feed after the intended downstream customer mix changed. Its significance is the connection between pellet choice, shaft-furnace operation and the HBI customer’s requirements. It supports investigating flexibility, not eliminating qualification. The plant-specific learning and product destination are part of the result.
For a procurement team, the useful next step is a joint review with the pellet supplier, DR operator and steelmaker. Agreement across that chain prevents a feed substitution that is attractive to one department from transferring cost or variability to another.
Technical references
Midrex / Cleveland-Cliffs — effect of BF-grade pellets on DR plant operations (June 2024) ↗
Midrex — the iron ore challenge for direct reduction ↗
References support the underlying principles. Diagnostic sequences, worked examples and procurement questions are original engineering analysis; they are not plant operating instructions or verified supplier performance results.