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Marsaco
A cement plant with silos and a preheater tower on the waterfront

Clinker

Grey Portland clinker in bulk, sourced worldwide and shipped to cement plants wherever there is demand.

The Programme

A cement plant cannot wait for its clinker. So we build supply as a programme, not a single cargo: several origins under review, cargoes consolidated from more than one producer, and the same inspection and payment terms on every shipment.

Specification

Spec per buyer's requirements

  1. 01

    55–65%C₃S

    Alite (tricalcium silicate)

    The main strength-giving phase, and the first indicator of clinker quality.

  2. 02

    < 1.5–2%f-CaO

    Free lime

    Uncombined lime. A low value shows the clinker was burned properly.

  3. 03

    94–98LSF

    Lime saturation factor

    Balance of lime to silica, alumina and iron. Relates to strength and burnability.

  4. 04

    ≤ 5%MgO

    Magnesium oxide

    Kept low to protect the long-term soundness of the cement.

  5. 05

    < 1%Na₂O eq.

    Alkalis (Na₂O + K₂O)

    Kept low to limit alkali–aggregate reaction in concrete.

  6. 06

    5–25 mmSize

    Nodule size

    Dry, free-flowing nodules, handled in bulk.

  7. 07

    1.2–1.5t/m³

    Bulk density

    Used to plan hold stowage and storage.

Typical ranges for grey Portland clinker (HS 2523.10), shown for reference. Each cargo is supplied to the buyer's own technical specification and inspected independently at the load port (SGS, Intertek or Bureau Veritas).

30,000+

Metric tonnes, minimum cargo

20

Clinker plants in our network

What is Clinker

Clinker is the main ingredient of Portland cement: the solid material that leaves the cement kiln, sintered into hard grey nodules.

  1. 01

    4raw materials

    Blend

    Limestone, clay, bauxite and iron ore, mixed in precise proportions.

  2. 02

    1,400°C

    Kiln

    The mix is heated in a rotating kiln until it begins to sinter.

  3. 03

    3–25mm

    Clinker

    It leaves the kiln as hard grey lumps and nodules: cement clinker.

  4. 04

    +gypsum

    Cement

    Ground in a mill with gypsum into the fine powder of Portland cement.

Why clinker is traded worldwide

  • 01

    Keeps for months

    Stored dry, clinker holds its quality for several months, so it can cross oceans without losing value.

  • 02

    Easy to handle

    It moves with ordinary mineral-handling equipment at loading and discharge ports.

  • 03

    Ships in bulk

    That is why clinker is traded internationally in large volumes, mainly on bulk carriers.

Aerial view of white limestone quarry terraces

Five steps, each with a document behind it.

  • Payment by irrevocable letter of credit at sight
  • Independent inspection, certificate per cargo
  • All terms subject to a signed contract

  1. Request

    Annual volume, cargo size, Incoterm, discharge port, specification and preferred origins.

  2. Origin matching

    Checked against our network for quality, route, timing and availability.

  3. Quotation

    Indicative FOB or CFR with specification, laycan and payment terms.

  4. Inspection

    Independent sampling at loading. A certificate of analysis per cargo, tied to payment.

  5. Shipment

    Loading within laycan, documents shared, vessel tracked to your terminal.