How Aluminium Is Made
From bauxite ore to precision-extruded architectural profiles: discover how aluminium is refined, smelted, shaped, finished and transformed into high-performance windows, doors and façades.
From mineral ore to architectural material.
Aluminium combines low weight, strength, corrosion resistance and exceptional design flexibility, making it one of the most important materials in contemporary architecture.
Yet aluminium does not occur naturally as ready-to-use metal. It begins with bauxite, a mineral-rich ore from which alumina — aluminium oxide — is extracted.
Alumina is then converted into primary aluminium through electrolysis. The metal can subsequently be alloyed, cast into billets, extruded into complex profiles, finished and fabricated into architectural systems.
Six stages from bauxite to aluminium profiles.
Primary aluminium production is based on two fundamental industrial processes — the Bayer process and the Hall–Héroult process — followed by casting and further processing into the forms required by industry.
Bauxite Mining
Bauxite ore is extracted as the principal raw material used for primary aluminium production.
Alumina Refining
The Bayer process separates aluminium oxide, known as alumina, from the bauxite ore.
Electrolysis
The Hall–Héroult process uses electrical energy to convert alumina into molten aluminium.
Casting
Molten aluminium is cast into forms such as ingots, slabs or billets for further processing.
Extrusion
Heated aluminium billets are forced through precision dies to create long architectural profiles.
Finishing & Fabrication
Profiles are finished, machined and assembled into windows, doors, façades and other building systems.
The material journey in numbers.
Producing primary aluminium requires several stages of concentration and refinement. Industry guidance commonly uses the following approximate mass relationship to explain the transformation from bauxite to aluminium.
It begins with bauxite.
Aluminium is one of the most abundant metallic elements in the Earth's crust, but it is naturally bound to other elements rather than found as pure metal.
The world's principal source of primary aluminium is bauxite, a mineral-rich ore containing aluminium oxide compounds together with iron oxides, silica and other minerals.
After mining, the bauxite is transported to a refinery, where the aluminium-bearing material begins its first major transformation.
The objective of the first production stage is not to make aluminium metal directly, but to isolate and refine aluminium oxide.
Turning bauxite into alumina.
The Bayer process is the industrial refining method used to separate aluminium oxide from bauxite and produce alumina — a fine white powder that becomes the feedstock for aluminium smelting.
Crushing
Bauxite is crushed and prepared so that its aluminium compounds can be efficiently processed.
Digestion
The ore is treated with caustic soda under controlled temperature and pressure.
Separation
Insoluble impurities are separated from the aluminium-rich solution.
Calcination
Aluminium hydroxide is heated to remove water, producing aluminium oxide — alumina.
The chemical building block of aluminium.
Alumina is aluminium oxide, chemically represented as Al₂O₃. After refining it appears as a fine white granular powder.
At this stage the aluminium is still chemically bonded to oxygen. A second industrial process is required to separate these elements and obtain metallic aluminium.
That transformation takes place inside large electrolytic cells using the Hall–Héroult process.
From alumina to molten aluminium.
Primary aluminium is produced through the Hall–Héroult electrolytic process, developed independently by Charles Martin Hall and Paul Héroult in 1886.
Alumina is dissolved in a molten electrolyte inside carbon-lined cells. A powerful electric current passes through the cell, separating the aluminium from its oxygen.
Molten aluminium collects at the bottom of the cell and is periodically removed for further processing.
Giving the metal its first usable form.
Once produced, molten aluminium is transferred to holding furnaces where its composition can be controlled and alloying elements may be added to obtain specific mechanical and processing properties.
The metal is then cast into semi-finished forms that can be processed by rolling, forging, extrusion or other manufacturing methods.
How aluminium becomes a window profile.
Architectural aluminium systems are based primarily on extruded profiles. A billet is heated until the metal becomes sufficiently malleable and is then pushed under pressure through a specially designed steel die.
From extruded profile to finished window.
Extrusion creates the aluminium profile, but a complete architectural window requires several additional manufacturing stages before it is ready to be installed in a building.
Thermal Break
Insulating elements separate the internal and external aluminium sections in thermally broken systems.
Surface Finish
Profiles may receive powder coating, anodising or specialised architectural finishes.
Machining & Assembly
Profiles are precisely cut, machined, joined and fitted with the specified hardware.
Glazing & Testing
Glass, seals and accessories complete the final high-performance aluminium element.
Aluminium naturally resists corrosion — and can be protected further.
When aluminium is exposed to air, a thin protective oxide layer forms naturally on its surface. This layer contributes significantly to aluminium's well-known resistance to corrosion.
Powder Coating
Architectural powder coating provides colour, surface protection and a wide choice of textures and finishes for windows, doors and façades.
Anodising
Anodising is an electrochemical process that increases the thickness of aluminium's natural oxide layer, creating a durable architectural surface.
Super Durable Finishes
Enhanced architectural coatings can be specified where increased resistance to weather exposure and long-term colour stability are required.
A material particularly suited to modern architecture.
The combination of structural, aesthetic and manufacturing characteristics explains why aluminium is widely used for windows, doors, façades and large glazed openings.
Aluminium combines relatively low weight with useful structural strength.
Appropriate alloys and engineered profile geometries can support demanding architectural applications.
Its naturally forming oxide layer helps protect the underlying metal.
Complex profile geometries can be created to integrate seals, hardware, glazing and thermal-break technology.
Aluminium supports slim profiles, large openings, custom geometries and a wide range of finishes.
Aluminium can return to the production cycle and be used again as a valuable secondary raw material.
Aluminium can return to the production cycle again and again.
Used aluminium can be collected, sorted, remelted and transformed into new aluminium products.
Producing secondary aluminium from scrap requires only a fraction of the energy associated with producing primary aluminium from ore.
Correct separation by alloy and controlled recycling are important because they allow high-quality aluminium to remain a valuable raw material for future applications.
The final product is the result of an entire industrial chain.
The aluminium frame visible in a modern building is the final result of mineral extraction, chemical refining, electrolysis, alloy development, casting, extrusion, surface finishing and precision fabrication.
Each stage contributes to the material characteristics that make aluminium suitable for contemporary windows, doors and façade systems.
From aluminium profile to complete architectural solution.
Mparolas Aluminium Systems manufactures high-performance aluminium windows, doors and façade solutions for residential, commercial and international architectural projects.