What is clinker as a sea-borne cargo?
Clinker is the half-made product of cement. It ships in bulk as an IMSBC Group C cargo, with a stowage factor of 0.65 to 0.85 cubic metres per tonne. It wears down hold steel, and it often loads hot, at 60 to 90 degrees Celsius, straight from the kiln.
Cement clinker is what comes out of a cement kiln before grinding. The kiln heats limestone, clay and small amounts of additives to around 1,450 degrees Celsius. They fuse into hard nodules of three to twenty-five millimetres. Those nodules are clinker. A cement plant near the buyers then grinds the clinker with gypsum into finished cement powder. At sea, clinker falls under the IMSBC Code 2024 schedule CEMENT CLINKER, in Group C. Group C means the cargo will not liquefy and carries no chemical hazard. The schedule is short because clinker is simpler to carry than cement. It still flags two issues that come up on voyage after voyage: wear on hold steel and loading temperature.
Clinker trade is the safety valve of the global cement industry. The big cement groups run kilns where energy and limestone are cheap (Vietnam, Turkey, Egypt, and China in the past). They ship the clinker to grinding plants near the buyers. This split is why clinker now fixes on Supramax ships more often than cement does. For brokers, clinker is one of the easier dry bulk cargoes to fix. Normal hold preparation is enough, and small leftovers from the previous bulk cargo rarely cause trouble.
Clinker cargo properties
| Property | Value | Unit / Reference |
|---|---|---|
| Stowage factor | 0.65 to 0.85 (typical 0.75) | m3/t (IMSBC Code 2024, CEMENT CLINKER schedule) |
| Bulk density | 1.20 to 1.50 | t/m3 (loose, IMSBC schedule) |
| Angle of repose | 30 to 40 | degrees (granular) |
| IMSBC group | Group C | IMSBC Code 2024 (no liquefaction risk, no chemical hazard) |
| IMSBC schedule entry | CEMENT CLINKER | IMSBC Code 2024, individual schedule |
| Hazard classification | Not classified as IMDG | Non-hazardous bulk; wears the surfaces it touches |
| Particle size | 3 to 25 mm nodules | Producer mill certificate |
| Moisture content | Typically less than 0.5 pct | Producer despatch advice |
| Self-heating | Nil once the kiln heat has gone | IMSBC schedule |
| Temperature on load | 60 to 90 deg C when loaded straight off the kiln; ambient after silo storage | Producer despatch advice |
| Abrasion to hold steel | Significant | P and I club guidance, IMSBC schedule |
| Cleaning category | Standard bulk; no food-grade cleaning needed | Industry hold-survey practice |
Vessel typing and parcel sizes
Clinker mostly moves on Supramax and Handysize ships. That follows from the parcel sizes and the routes. Most intra-Asia and intra-Mediterranean clinker goes on geared Supramax ships. Panamax ships appear now and then on long routes, where the parcel is big enough to justify the deeper draught. Capesize ships do not carry clinker. Clinker terminals at both ends handle smaller parcels, and the wear on Capesize hold steel does not pay over the life of a cargo trade.
| Vessel class | Suitability | Typical parcel size | Notes |
|---|---|---|---|
| Capesize | Rare | Not standard for clinker | Terminal draught and parcel sizes rule it out; see Capesize |
| Panamax | Occasional, on long routes | 55,000 to 70,000 mt | Used when the producer can build one large parcel; see Panamax |
| Supramax | Dominant | 45,000 to 55,000 mt | Geared ships preferred at ports with few shore cranes; see Supramax |
| Handysize | Strong | 20,000 to 35,000 mt | The main ship on short intra-Asia and Mediterranean routes; see Handysize |
| Handymax | Used | 40,000 to 50,000 mt | An in-between size; geared 5x30 tonne ships can serve most clinker discharge ports; see Handymax |
Ship choice usually comes down to two questions. How deep is the water at the receiving port? Does the receiver expect the ship to discharge with its own gear? Grinding plant berths in Bangladesh and the Philippines usually take Handysize draught and need geared ships. Receivers in the Mediterranean and West Africa vary. Loading ports in Vietnam and Turkey can take any of the four classes above. A broker who handles clinker orders usually keeps a list of open geared Supramax ships with grabs of about five by thirty tonnes. That is the default match. See vessel size comparison for dimensions, and voyage charter for how parcel size feeds into the freight quote.
How clinker ships in practice
Producer terminals load clinker by enclosed conveyor or by grab. Vietnam’s main clinker export berths use conveyors that load 7,000 to 10,000 tonnes per day. Turkish Mediterranean terminals load at similar rates. Grab loading at less well equipped ports runs at 3,000 to 5,000 tonnes per day. The cargo trims well because the granules build a stable cone. The master normally lets the cargo settle at its angle of repose, which is the slope a loose pile takes by itself. The crew does not push it into the corners.
Hold preparation for clinker is standard. The holds must be clean and dry. You do not need the near food-grade cleaning that cement demands. A clinker cargo can follow grain, coal or iron ore, as long as the holds are swept and washed to standard. Hold surveys are lighter than for cement. A master’s certificate is usually enough, and an independent surveyor is the exception. That is why clinker fixes more easily than cement on the same ships. For the details, see notice of readiness and laytime.
Care during the voyage is light. The holds are closed and not ventilated, and the cargo stays stable. The crew does not work the cargo in heavy weather, because clinker is abrasive. Discharge is almost always by grab, and sometimes by clamshell at specialist receivers. Typical discharge rates are 4,000 to 6,000 tonnes per weather working day. Wear on hold paint and tank-top steel (the floor of the hold) is the cost that builds up. A ship that carries clinker on five voyages in a row will need hold paint touch-up sooner than its maintenance plan expects. Owners build this into the freight quote. See loading and discharge rate and demurrage for how laytime turns these rates into money.
Major trade routes
Clinker mostly moves on short and medium routes, and intra-Asia trade carries the most volume. The main routes are:
-
Vietnam to the Philippines. This is the largest intra-Asia clinker route by volume. Vietnamese cement producers (Vicem, Vissai and others) ship clinker to Philippine grinding plants on Supramax and Handysize ships. Round trips take five to eight days. The route has carried several million tonnes a year, steadily, since the late 2010s.
-
Vietnam to Bangladesh. Bangladesh has run short of clinker for a long time. Grinding plants around Chittagong and Mongla import clinker to make cement for the home market. Handysize and Supramax ships make round trips of ten to fourteen days. Draught limits at the Bangladeshi end come up often, and they push the choice toward smaller geared ships.
-
Turkey and Egypt to Africa and the Mediterranean. Turkish kilns, especially around Iskenderun and Aliaga, export clinker to West Africa, the Levant and parts of southern Europe. Voyages run from three days inside the Mediterranean to fifteen days for West Africa. Supramax is the main ship size.
-
Intra-Asia (Thailand, Indonesia, Malaysia). These smaller routes supply regional grinding plants. They often use ships from the Vietnam to Philippines route during its slack periods.
-
North-West Europe to construction-boom markets. Northern European producers ship clinker to grinding plants in West Africa and the Caribbean when local kilns cannot keep up. Volumes are lower than on the intra-Asia or Turkey routes. Brokers still see these orders regularly.
For trade volumes, we use CEMnet and Global Cement Magazine quarterly statistics and the Vietnam Cement Association annual exports report. We also use reports from Vicem, Holcim, Heidelberg Materials and CRH. Check route volumes against current Global Cement trade data before you quote numbers in a fixture pitch.
Clinker vs cement
Clinker or cement is the question brokers get asked most often. One comes from the other: clinker comes out of the kiln, and cement is the ground end product. They still trade as two separate cargoes, and they ship in different ways.
| Clinker | Cement | |
|---|---|---|
| IMSBC schedule | CEMENT CLINKER | CEMENT |
| IMSBC group | Group C | Group C |
| Stowage factor (m3/t) | 0.65 to 0.85 | 0.65 to 0.75 |
| Form | Hard granular nodules, 3 to 25 mm | Fine grey powder, less than 75 microns |
| Loading temperature | 60 to 90 deg C when loaded straight off the kiln | Ambient to about 60 deg C |
| Dust profile | Moderate (granular) | Severe (flows like a fluid in the hold) |
| Hold cleanliness | Standard bulk | Very high (near food-grade cleaning) |
| Abrasion on holds | High (wears hold steel) | Low |
| Moisture risk | Lower (granules can take some wetting) | High (sets hard for good) |
| Vessel preference | Supramax, Handysize | Handysize, Supramax, specialist cement carrier |
| Discharge complexity | Grab and conveyor; wears the equipment | Pneumatic or grab; dust complaints common |
| Relative fixture difficulty | Easier | Harder |
In chartering terms, cement cleans up after you, and clinker wears your holds down. A ship that has just discharged clinker is in good shape to load grain, coal, iron ore or fertilizer next. A ship that has just discharged cement needs a careful hold survey before it is offered for the next cargo, if leftover residue is a concern. The related page is scrap metal. Scrap is the only cargo that wears hold steel more than clinker does. Most owners keep it apart from the ships they use for cement and clinker.
Reference example
Supramax clinker, Vietnam to the Philippines
- Cargo
- 50,000 mt bulk cement clinker, loaded straight off the kiln
- Lane
- Cam Pha or Nghi Son range to Cebu or Manila range
- Vessel
- Geared Supramax, 55,000 to 60,000 dwt, 5x30 tonne grabs
- Laycan
- 7 day window
- Loading rate
- 8,000 mt per weather working day SHINC
- Discharge rate
- 5,000 mt per weather working day SHEX
- Key clauses
- GENCON 2022 amended, temperature certificate at load, demurrage USD 14,000 per day pro rata, freight on delivery
The route is around 1,200 to 1,500 nautical miles each way. It is one of the most efficient intra-Asia bulk routes. Port-to-port cycles of five to eight days keep the ship earning close to the Baltic Supramax index for the segment during the season.
The temperature certificate at load decides whether loading goes ahead. Clinker straight off the kiln above 90 deg C is rejected. Clinker cooled in a silo to below 60 deg C is accepted with no further survey. Vietnamese conveyors load at 8,000 tonnes per weather working day, and Philippine grab gear discharges at 5,000 tonnes per day. These rates give a fixed round-trip time, so owners can plan three to four lifts in a row.
Freight is paid on delivery on this route. The Vietnamese shipper and the Philippine receiver usually belong to established cement groups that deal with each other. Demurrage of USD 14,000 per day matches the daily Supramax TCE (time charter equivalent earnings) for the segment in that quarter.
The fixture is anonymised. The figures show typical market terms for the route.
Common loading and discharge issues
- Abrasion wear on hold paint and tank-top steel. Clinker nodules grind the hold steel when the cargo moves in heavy weather and during grab discharge. You will not see the damage after one voyage, but it shows over several. Owners who plan many clinker voyages should price an early hold paint touch-up into the freight quote.
- High temperature on prompt-loaded clinker. Clinker loaded straight off the kiln at 80 to 90 deg C can damage hold paint and expand the hatch coamings. It can also cause condensation on cool hold sides in the first 48 hours of the voyage. The fix is a temperature certificate at load with a written limit.
- Discharge dust restrictions at urban ports. Clinker is less dusty than cement. Grab discharge at the quay still raises enough dust to trigger air-quality stoppages at some ports, notably in the Philippines and Bangladesh. The laytime clause should say whether these stoppages count as weather interruptions.
- Quantity dispute on draught survey. Granular clinker leaves two to five per cent air space in the hold, depending on hold shape and loading speed. Draught survey differences of one per cent are routine. The freight clause should cover them with a tolerance band, so they do not turn into disputes.
- Hot weather monsoon delays on Asian lanes. Monsoon swell at Philippine and Bangladeshi anchorages can delay notice of readiness by 24 to 72 hours. The recap should say whether waiting time at anchor counts toward laytime.
- Cross-contamination with the previous cargo. Clinker loaded after salt, sugar or fertilizer can pick up a thin film of residue. That film can affect grinding at the receiver’s mill. Cement groups usually require a hold survey certificate that confirms the previous cargo or rules out certain cargo types.
Scope and what this page does not cover
This page covers bulk clinker on dry bulk ships. It does not cover grinding chemistry, kiln operation, cement plant economics or the wider cement and concrete industry. To plan a clinker programme, talk to our dry bulk brokers. We work from current Baltic Exchange and producer data. Check all IMSBC values against the current 2024 IMSBC Code at the load port. To price a clinker cargo, get a quote.