What is alumina as a sea-borne cargo?
Alumina is aluminium oxide, a fine white powder refined from bauxite and carried in dry bulk under the IMSBC Code ALUMINA schedule. Smelter-grade alumina is the feedstock for aluminium smelters, classified Group C, dusty and free-flowing rather than chemically hazardous.
Alumina sits in the middle of the aluminium value chain. Bauxite ore is mined, refined into alumina at a refinery through the Bayer process, then shipped to a smelter where it is reduced to primary aluminium. Each tonne of aluminium takes roughly two tonnes of alumina, and each tonne of alumina takes roughly two to three tonnes of bauxite, so the alumina trade is large but smaller in tonnage than the bauxite trade that feeds it. The shipping problem is distinctive: alumina is a low-value, abrasive, extremely dusty powder that flows almost like a liquid and gets everywhere.
The regulatory anchor for sea carriage is the IMSBC Code 2024, schedule entry ALUMINA. The schedule classifies smelter-grade alumina as Group C, meaning it presents neither a liquefaction risk (Group A) nor a chemical hazard (Group B). The operational concerns are physical, not chemical: dust generation during loading and discharge, free-flowing behaviour that can shift in a seaway, and abrasion of handling gear and coatings. Note that the related schedules ALUMINA HYDRATE and ALUMINA, CALCINED cover finer or chemically distinct fractions that behave differently, and a fixture should name the correct grade.
Alumina cargo properties
| Property | Value | Unit / Reference |
|---|---|---|
| Stowage factor | 0.93 to 1.11 | m3/t, smelter-grade, varies by source (generalized; verify against IMSBC ALUMINA schedule) |
| IMSBC group | Group C | Not liquefiable, not a chemical hazard (IMSBC Code 2024, ALUMINA schedule) |
| IMSBC schedule entry | ALUMINA | Smelter-grade aluminium oxide; distinct from ALUMINA HYDRATE and ALUMINA, CALCINED |
| Bulk density | 0.90 to 1.08 | t/m3, source dependent (generalized; verify against IMSBC ALUMINA schedule) |
| Angle of repose | Approximately 30 to 35 degrees | Free-flowing, non-cohesive (generalized industry value; verify against schedule) |
| Transportable moisture limit | Not applicable | Group C, TML applies only to Group A cargoes |
| Dust / flow hazard | Highly dusty, free-flowing, abrasive | IMSBC Code ALUMINA schedule, hazard and precautions text |
| Reference | IMSBC Code 2024 edition | International Maritime Solid Bulk Cargoes Code, IMO |
The defining property of smelter-grade alumina is that it behaves like a dense, dusty fluid. Particle size sits in the tens to low hundreds of microns, which is fine enough to become airborne in a cloud during loading yet coarse enough to flow and pack densely in the hold. Because it is non-cohesive and free-flowing, alumina can run and shift if a hold is not properly filled and trimmed, and its low angle of repose means cargo settles into a flat, mobile surface. The IMSBC ALUMINA schedule treats it as Group C, so there is no transportable moisture limit and no liquefaction test, but the dust and flow behaviour drives the real operational care.
Vessel typing and parcel sizes
| Vessel class | Suitability | Typical parcel size | Notes |
|---|---|---|---|
| Panamax | Dominant | 60,000 to 80,000 t | Workhorse for long-haul alumina from Australia and West Africa refineries to Middle East and Asian smelters. Sealed holds preferred for dust control. |
| Supramax | Common | 45,000 to 60,000 t | Geared tonnage for smelters without shore unloaders; gear and grabs exposed to alumina abrasion. |
| Handymax | Common | 35,000 to 50,000 t | Regional and shorter-haul lanes; flexible berth fit at smaller smelter ports. |
| Handysize | Conditional | 20,000 to 35,000 t | Niche and coastal redistribution lanes. Higher freight per tonne. |
| Capesize | Rare | Not typical | Alumina parcels and smelter receiving ports rarely justify Capesize. Bauxite, the feedstock, is the Capesize cargo. |
Alumina parcel-size economics are set by the size of the receiving smelter, the draught of the smelter port, and the dust-handling capability of the berth. The trade runs predominantly on Panamax and Supramax tonnage because smelter intake parcels are sized to a few weeks of pot-line feed rather than the very large parcels that bauxite refineries take. The feedstock bauxite trade runs on Capesize tonnage, but alumina itself rarely justifies Capesize because both the parcel sizes and the smelter ports are smaller.
Dust control drives vessel selection as much as parcel size. Operators favour vessels with hatch covers and hold seals in good condition, because alumina dust penetrates poorly sealed coamings and contaminates accommodation, machinery and adjacent cargo on a backhaul. Geared Handymax and Supramax vessels are common where the smelter lacks a dedicated pneumatic or screw unloader, but the abrasive cargo accelerates wear on the ship’s own cranes and grabs.
How alumina ships in practice
Alumina loads predominantly by enclosed conveyor or pneumatic system at refinery export terminals, which are designed to contain the dust. Loading rates at modern refinery berths are high, often in the tens of thousands of tonnes per day, because the cargo flows freely and the terminal handling is automated. The loading plan must fill and trim holds to limit the free surface, since a part-filled hold of free-flowing alumina can shift in heavy weather. Hatch covers are sealed after loading to keep dust in and moisture out.
Voyage care for alumina is light compared with a chemically active Group B cargo. There is no self-heating, no gas monitoring and no liquefaction risk, so the daily regime centres on keeping hatches sealed, watching for water ingress and confirming that the trimmed surface has not slumped. Alumina is mildly hygroscopic, so the operational priority is preventing rain and spray from reaching the cargo, which can cause caking at the surface and complicate discharge.
Discharge is the more demanding end of the voyage. Many smelters take alumina through enclosed pneumatic or screw unloaders to control dust, but where the receiver discharges by grab and shore crane the dust nuisance and abrasion are significant. The fixture is almost always on FIO terms with laytime and demurrage negotiated against the smelter’s published norm. See loading and discharge rate for the contractual mechanics, and note that alumina rarely part-loads with other cargoes because of the cleaning cost and cross-contamination risk.
Major trade routes
- Australia to the Middle East: a major smelter-grade alumina flow from Australian refineries to Gulf smelters, Panamax and Supramax dominant. (Volume estimate open; desk-flag.)
- Australia to China and Northeast Asia: alumina into Chinese and other Asian smelters, Panamax dominant, sensitive to Chinese domestic refinery output and policy. (Volume estimate open; desk-flag.)
- West Africa and Brazil to smelters worldwide: refinery output from Atlantic-basin alumina plants moving to Middle Eastern and other smelters, Panamax and Supramax. (Volume estimate open; desk-flag.)
- India to regional smelters: Indian refinery output serving domestic and nearby smelters, Supramax and Handymax. (Volume estimate open; desk-flag.)
- Intra-Atlantic and intra-Pacific balancing flows: shorter-haul alumina movements that balance refinery surplus against smelter deficit within a basin, Handymax and Handysize. (Volume estimate open; desk-flag.)
The alumina trade map is downstream of where bauxite refineries and aluminium smelters are located, which often do not sit in the same country. Gulf smelters in particular are large alumina importers because they are sited for cheap energy rather than near bauxite or refining capacity. For per-lane tonnage, the authoritative public sources are the International Aluminium Institute, UNCTAD and Clarksons trade-flow data, and any figure here should be verified against them before quoting. For the wider lane catalogue across dry bulk see the dry-bulk-shipping hub.
Alumina vs bauxite
Alumina and bauxite are consecutive links in the same aluminium chain and are routinely conflated, but they are very different cargoes to ship. Bauxite is the raw ore that is refined into alumina; alumina is the refined intermediate that is smelted into aluminium.
| Alumina (smelter-grade) | Bauxite | |
|---|---|---|
| Stage in chain | Refined intermediate (aluminium oxide) | Raw mined ore |
| IMSBC group | Group C | Group A or C depending on grade and moisture |
| Liquefaction risk | None (Group C) | Possible for fine, wet grades (some bauxites carried as Group A) |
| Physical form | Fine white free-flowing powder | Lumpy to fine reddish ore, often moist |
| Dominant hazard | Dust, free-flowing shift, abrasion | Liquefaction (fine grades), dust |
| IMSBC schedule | ALUMINA | BAUXITE / BAUXITE FINES |
| Typical vessel | Panamax, Supramax | Capesize |
The most important difference for chartering is the liquefaction profile. Smelter-grade alumina is Group C and does not liquefy, so it carries no transportable moisture limit and no can-test obligation. Certain fine, wet bauxites by contrast have been carried as Group A and require moisture-limit certification, a distinction that has driven major casualty investigations in the bauxite trade. A fixture written against the wrong cargo description or the wrong schedule will fail the loadport survey, so the cargo name on the booking must be precise.
Reference example
Panamax smelter-grade alumina, Western Australia to the Arabian Gulf
- Cargo grade
- 70,000 mt smelter-grade alumina (aluminium oxide), in bulk
- Lane
- Western Australia refinery berth to Arabian Gulf smelter port
- Vessel band
- Modern Panamax, 76,000 dwt, well-sealed hatch covers
- Parcel size
- 70,000 mt
- Loading rate
- 30,000 T/D SHINC, enclosed shiploader
- Discharge rate
- 15,000 T/D SHINC, pneumatic / screw unloader at smelter
- Notable clause
- Dust-control and hold-sealing clause, hatch covers weather-tight on departure, cargo carried under IMSBC ALUMINA schedule, freight prepaid against original BL
The lane is a representative long-haul alumina flow feeding an energy-sited Gulf smelter that has no domestic refining capacity. Loading at the refinery export berth uses an enclosed shiploader designed to contain dust, which keeps the rate high and the loadport claim risk low compared with grab loading.
Hold preparation focused on hatch-cover weather-tightness and seal condition rather than the chemical cleanliness a Group B cargo would demand, because the controlling risk on alumina is dust escape and water ingress, not residue contamination. The master confirmed all holds were trimmed and the free surface minimised before departure, since free-flowing alumina can shift in a seaway if a hold is left part-filled.
The fixture was on FIO terms with laytime calculated against weather working days SHINC at both ends. Discharge was the rate-limiting end because the smelter took the cargo through an enclosed unloader to control dust, which is slower than open grab discharge but contained the nuisance at a port with residential adjacency. Demurrage was set close to the spot Panamax daily TCE for the month of fixture.
Common loading and discharge issues
- Dust generation at the load and discharge berths: alumina is one of the dustiest dry bulks in routine trade. Enclosed shiploaders and pneumatic unloaders contain it; open grab handling does not, and dust complaints at ports with residential adjacency can drive discharge restrictions or fines passed back to the charterer under the cargo handling clause.
- Free-flowing cargo shift: because alumina is non-cohesive with a low angle of repose, a part-filled or poorly trimmed hold can shift in heavy weather. The IMSBC ALUMINA schedule treats trimming and hold filling as the primary stability precaution rather than a liquefaction can-test.
- Water ingress and surface caking: alumina is mildly hygroscopic, so rain or spray reaching the cargo through a leaking hatch can cake the surface and slow pneumatic discharge. Hatch-cover seal condition is the controlling pre-loading check.
- Abrasion of cranes, grabs and coatings: alumina is abrasive and accelerates wear on the ship’s own gear and on tank-top and hopper coatings over repeated voyages, a hidden cost that compounds across an alumina-heavy fleet’s drydock cycle.
- Wrong-schedule or wrong-grade booking: confusing smelter-grade ALUMINA with ALUMINA HYDRATE or ALUMINA, CALCINED, which are separate IMSBC schedules with different dust and density behaviour, causes certificate delays at the loadport. The booking must name the exact grade and schedule.
- Cross-contamination on backhaul: residual alumina dust in coamings and on deck can contaminate a subsequent clean cargo, so an alumina voyage usually requires a full hold and deck wash before resetting to grain or another sensitive cargo.
Scope and what this page does not cover
This page explains smelter-grade alumina as a sea-borne dry bulk commodity, the IMSBC operational regime that governs its carriage, and the dominant vessel-class and lane structure. It does not forecast alumina or aluminium prices, opine on which refinery or smelter to fix from in the next quarter, or interpret jurisdiction-specific cargo-claim case law. The cargo properties here are generalized industry values and should be confirmed against the IMSBC Code 2024 ALUMINA schedule for any specific fixture; trade-volume and route figures should be confirmed against International Aluminium Institute, UNCTAD or Clarksons data before quoting. For those, work with chartering counsel and a desk broker against current Baltic Exchange and named market data. To price an alumina fixture, get a quote.