Stacked aluminium billets in a factory, illuminated by bright overhead lights.

How aluminium is made and why it matters

The journey from red rock to the metal we use every day.

Aluminium is everywhere. It’s light, strong, and durable, making it the ideal material for things like window frames, vehicle parts, food or drink packaging and power cables. 

But where does aluminium come from and how is it made?

Understanding the journey from red rock to metal helps explain aluminium’s versatility and why the way it's produced matters. 

Key takeaways: 

  1. Aluminium starts as bauxite, a reddish-brown rock found in the ground. Bauxite is refined into alumina, a fine white powder, which is then smelted into aluminium metal. 
  2. Aluminium is widely used because it’s light, strong, corrosion-resistant, conductive, malleable, and recyclable.  
  3. Global demand for aluminium is expected to increase by almost 40% by 20301. Producing aluminium is energy-intensive - how it’s made matters. 
  4. Rio Tinto is investing in technologies like ELYSIS® and AP60 while expanding recycling to produce more of our aluminium more efficiently while working to reduce production-related emissions.

How do you make aluminium?

From red rock to white powder – how we get alumina from bauxite 

To make aluminium, we need to start in the ground with bauxite, a naturally-occurring, reddish-brown ore often found in tropical and subtropical regions like Brazil, Guinea and parts of Australia. 

A site worker with gloves holding a handful of bauxite
Bauxite is known for its reddish hue – a result of the iron oxides present in the ore.
Covered conveyor system transporting bauxite ore through a steel-framed industrial structure, with mountainous terrain visible in the background.
A conveyor at our BC Works operations in Kitimat in Canada moves alumina across the site

After bauxite is mined, the ore is transported to a refinery where it’s processed to extract a fine white powder called alumina using a multistep industrial process called the Bayer process.

From powder to molten metal – how alumina becomes aluminium 

After alumina is refined, it gets transported to a smelter where it's dissolved in a molten bath and an electric current is passed through it, separating aluminium from oxygen.  

The result is molten aluminium which is then cast into different forms like ingots, billets or slabs. These can then be rolled, extruded or shaped depending on what customers need. 

  • How is aluminium made?

    Before aluminium becomes the shiny metal we all recognise, it starts as bauxite, a reddish-brown ore found in the ground. Bauxite is mined and processed into a fine white powder called alumina which is then used to produce aluminium.

4-5

tonnes

bauxite needed to produce about 2 tonnes of alumina

~2

tonnes

alumina needed to produce 1 tonne of aluminium

556

pounds

projected amount of aluminium per vehicle by 2030.

Source

What is aluminium used for? 

Aluminium is useful because it combines several useful properties in one material: 

  • light, but strong
  • resistant to corrosion
  • a good conductor of electricity
  • malleable, which means it can be shaped, rolled, cast and extruded
  • recyclable, so it can be used again and again.

Often, it does several of these things at once.  

And because it’s so versatile, aluminium can be mixed and combined with other elements to form specialised alloys or products, depending on what it’ll be used for. 

That’s why aluminium appears in so many parts of everyday life.

  • Why is aluminium used in so many things?

    Aluminium is widely used because it’s light, strong, corrosion-resistant, conductive, malleable and recyclable.

    It can also be combined with small amounts of other elements to make specialised alloys for different uses.

    These properties make aluminium useful in buildings, transport, packaging, electrical systems and renewable energy infrastructure.

  • Does aluminium rust?

    No. Aluminium does not rust in the same way iron or steel can rust.

    Rust is a form of iron oxide, and aluminium doesn’t contain iron in its pure form.  

    Instead, when aluminium is exposed to air, it naturally forms a very thin oxide layer on its surface. This layer helps protect the metal from further corrosion which is one reason it's used in buildings, vehicles, and packaging. 

  • Does aluminium conduct electricity?

    Yes. Aluminium conducts electricity.

    It’s not as conductive as copper, but it’s lightweight and can be cost-effective in many electrical applications. That combination makes aluminium useful in power cables, transmission lines, electrical components and renewable energy infrastructure.

    Because aluminium is lighter than copper, it can be especially useful where weight matters or where long spans of electrical conductor are needed.

  • What is the melting point for aluminium?

    The melting point of aluminium is about 660°C or 1,220°F.

    This means aluminium changes from solid to liquid at a much lower temperature than some other metals like steel. This is important in casting, recycling and manufacturing, where aluminium can be melted and reshaped into new products.

Why does the way aluminium is made matter? 

Aluminium is already part of everyday life, and demand is expected to keep growing — by almost 40% globally by 20301 — which makes how it’s produced increasingly important. 

From bauxite mining to alumina refining, smelting and recycling, each stage of the value chain has environmental considerations. 

We’re working across several areas to produce more of the aluminium the world needs, responsibly:

Energy

How does energy affect aluminium’s carbon footprint? 

Energy is one of the biggest factors in aluminium’s carbon footprint: smelting one tonne of primary aluminium uses about 14 megawatt hours of electricity2 – roughly the amount an average Canadian household uses over 15 months3. 

Our 7 hydropower plants in Quebec and British Columbia generate most of the electricity we use at our aluminium operations in Canada. New Zealand’s aluminium smelter (NZAS) and Tasmania’s Bell Bay smelter also primarily use hydroelectricity to convert alumina into aluminium.  

In Australia, we’ve been working on a competitive repowering solution for our aluminium operations at Gladstone for several years to transition away from fossil fuels.

Repowering large industrial assets with renewables, when they were built to run on coal and gas, is complex but we’re making good progress. We’ve contracted more than 2.8 gigawatts (GW) of new renewable energy and more than 600 megawatts (MW) of storage capacity including: 

  • 1.1GW of solar electricity from Upper Calliope Solar Farm, to be built near Gladstone 
  • 1.1GW of wind energy from the Bungaban Wind Farm in Queensland 
  • 90% of electricity and battery storage capacity from Edify Energy’s Smoky Creek and Guthries Gap Solar Power Stations, which includes a 600MW solar farm and a 2,400MWh battery energy storage system 
  • 40% of Lightsource bp’s Lower Wonga Solar Power Station under construction near Gympie, equivalent to 112MW/3.24MWh of power and associated battery storage. 

We also have support from the Queensland and Australian governments to help secure internationally competitive energy to continue aluminium production at Boyne smelter until at least 2040.

Together, these agreements help preserve Queensland’s fully integrated aluminium value chain from bauxite mining to smelting and supports thousands of regional jobs and onshore manufacturing.

They also position Boyne smelter to be one of the world’s first aluminium smelters underpinned by solar and wind power, making Rio Tinto Australia’s largest industrial offtaker of renewable energy. 

Research and innovation

What technologies are changing aluminium smelting?

Technology is changing how we produce aluminium: providing the potential for more metal, more efficiently with fewer emissions. 

One example is AP60, is our proprietary aluminium smelting technology.  

It’s designed to produce more aluminium per cell than conventional smelting technologies, helping improve productivity and efficiency.  

  • What is AP60?

    Developed by our research and development teams, the AP60 smelting technology is:

    • highly productive - each pot produces more than 4.5 tonnes of aluminium per day
    • space-efficient - AP60 produces more aluminium per square metre needing less physical infrastructure to achieve the same output.

    When powered by carbon-free electricity, as it is with hydropower at our Arvida smelter in Quebec, it can produce aluminium with a significantly lower carbon footprint than the global average4.  

Anodes - large carbon blocks - are essential in the process of turning alumina into aluminium metal. Their job is to help carry the electric current that separates aluminium from oxygen.   

In traditional smelting, carbon anodes are “consumed” as they react with oxygen, creating direct greenhouse gas emissions.
Anode before and after consumption in the aluminium smelting process.
Carbon anode before and after consumption in the aluminium smelting process.

ELYSIS, our joint venture with Alcoa, has developed technology that replaces carbon anodes with inert anodes. The venture is supported by the governments of Canada and Quebec, through Investissement Québec, as well as Apple.  

Compared to the conventional smelting process, using inert anodes eliminates direct greenhouse gas emissions from the smelting process, producing oxygen instead. We’re currently testing the commercial-sized cell in an industrial demonstration plant at our smelter in Alma in Quebec.  

While technology doesn’t remove every challenge in the aluminium value chain, it’s an important part of how we’re working to produce aluminium more efficiently and with a lower emissions profile.

Circularity

Is aluminium recyclable?

Aluminium can be recycled again and again, using up to 95% less energy than producing primary aluminium5. 

This makes recycled aluminium, also known as secondary aluminium, an important part of meeting rising demand for lower-carbon aluminium while reducing the strain on primary production.

Animated gif showing recycling journey of aluminium

We’re helping to bolster aluminium supply with our Matalco joint venture, which produces recycled aluminium products in North America. We’ve also developed closed-loop systems with partners in Australia to keep the metal circulating and in use.  

Aluminium will remain essential to everyday life and the infrastructure of the future. The challenge and opportunity are to meet growing demand, while continuing to improve how the metal is produced and kept in circulation.