Interactive: Aluminum supply chain: Indonesia emerges from ores to ingots

Indonesia is currently restructuring its mineral industries following the nickel boom. Aluminum now sits at the center of this national industrial strategy, especially at a time when the global aluminum market is facing mounting uncertainties amid war in the Middle East.

With the government doubling down on resource nationalism and pushing downstream integration, Indonesia is attempting to build an end-to-end value chain that moves from bauxite ores to downstream aluminum ingots.

Ban on raw bauxite exports

In a bid to build its end-to-end aluminum chain, Indonesia implemented a ban on raw bauxite exports in 2023, redirecting ore flows into the domestic market and forcing investment in refining and smelting capacity.

However, Indonesia still imports a small amount of bauxite, totaling 512 dry metric tons in 2025, according to Statistics Indonesia.

Potential bauxite supply curbs in Guinea are likely to further add to Indonesia's importance in the global aluminum space, given the country's well-integrated alumina and aluminum facilities.

The objective is clear: replicate the success of Indonesia's nickel playbook by capturing more value onshore, anchoring industrial ecosystems, and reducing exposure to imported materials. However, that policy now intersects with a global aluminum market under acute strain.

The global aluminum market is tipping deeper into deficit following damage to major Middle Eastern smelters, pushing LME aluminum prices above $3,600/mt and widening the projected 2026 deficit to 764,000 mt, according to analysts with S&P Global Energy CERA. Indonesia's downstream build-out is, hence, no longer a policy experiment -- it is increasingly relevant to regional and global supply resilience.

Alumina: from bottleneck to strategic export lever

Alumina -- a product of bauxite and the feedstock for aluminum -- remains the most critical hinge in Indonesia's ambition for its aluminum supply chain. While Indonesia still relies on imported alumina for part of its smelting needs, it has also emerged as an alumina exporter, with capacity expanding as refineries with Chinese investments continue to ramp up.

China-backed alumina projects have reached commercial operation over the past two years, allowing Indonesia to process more domestic bauxite and export surplus alumina into the seaborne market. Indonesia's alumina exports in 2025 stood at 5.26 million mt, accounting for around 66% of its alumina production capacity in 2025, according to S&P Global Commodities at Sea data.

Further Indonesian alumina capacity is expected to come online this year, reinforcing the country's position as a meaningful midstream supplier. Indonesia's alumina refining capacity is expected to reach around 9 million mt/year this year, according to market sources.

Indonesia's growing alumina refining capacity, however, currently coincides with persistent global alumina oversupply, intensified by Middle East smelter curtailments that reduced demand faster than refinery output could adjust.

Platts, part of S&P Global Energy, assessed alumina FOB Australia at $310/mt FOB Western Australia April 30.

Platts also assessed CIF China spot bauxite at $66/dmt April 30 for low temperature ore with 45% alumina and 3% silica, while FOB Guinea spot bauxite was assessed at $33/dmt April 30.

Middle East disruptions redefine aluminum supply

The conflict in the Middle East has disrupted global aluminum supply through damage to major smelters in the Gulf, potentially removing 1.4 million-2 million mt of annualized capacity, with recovery timelines extending up to a year.

Although global aluminum output showed headline growth in March, production in the Gulf fell 6% year over year in March to 495,000 mt.

Concurrently, the effective closure of the Strait of Hormuz has stranded raw materials and finished metal, further tightening global metal availability.

Emergency supply responses spotlight Indonesia

Smelters outside of the Middle East have mobilized spare capacity where possible. Alcoa has restarted and ramped up smelters across Australia, Europe and Brazil to backfill disrupted supply. Century Aluminum has also announced the early restart of the second potline of its Norðurál smelter in Grundartangi, Iceland, bringing operations back online several months ahead of schedule. These restarts, however, underscore a broader market reality: new, politically insulated aluminum units are scarce and increasingly valuable.

Structural aluminum smelting capacity growth in Indonesia, driven by new production ramp-ups over the past years and in the coming years, is likely to provide buyers in the global space, especially in Asia, to reassess sourcing strategies. Indonesia was a net exporter of 326,235 mt of unwrought aluminum in 2025. Meanwhile, the country's aluminum smelting capacity is expected to reach 7.6 million mt/year in the next two years, according to market sources.

Indonesia's strategic role expands

Indonesia's rising importance, however, extends beyond capacity growth. Recent critical minerals cooperation agreements with Japan and South Korea explicitly emphasized energy and resource security amid disruptions in the Middle East. The agreements cover multiple critical minerals and reinforce Indonesia's position as a long‑term industrial supply partner for the two key aluminum‑consuming economies.

"We expect the continued smooth ramp-up of new capacity in Indonesia to help to offset losses [from the Middle East]," said S&P Global CERA analysts, adding that "Indonesian projects are facing some internal opposition at present, but we do not expect this to have an impact on shorter-term plans."

Platts assessed the CIF Japan spot premium for 99.7% P1020/P1020A aluminum ingot at the Main Japanese Ports at $315/mt plus London Metal Exchange cash on April 30.

Platts assessed the CIF main Asian ports spot premium for 99.7% P1020/1020A aluminum ingot at $280/mt plus LME cash on April 30.