Primary smelting: metal production before alloy manufacture

What electrolysis achieves

Conventional primary production uses electrolysis to separate aluminium from alumina in a molten electrolyte. Hydro describes carbon anodes reacting with the oxygen released from alumina and producing carbon dioxide. The resulting liquid metal is then transferred to the casthouse. This distinction explains why the smelter process and the subsequent alloy-manufacturing stage should have separate entries in a route description.

Power claims need a boundary

An electricity-related claim does not automatically describe all emissions associated with production. Ask whether reported information covers electrolysis, anode manufacture, alumina refining, casting and transport. Record the reporting year, methodology and verification evidence before comparing two offers. A renewable-electricity statement alone is insufficient evidence for a whole-product footprint.

Alloy identity is downstream

At the casthouse, alloy additions and casting convert liquid metal into feedstock for particular manufacturing routes. Ask for the specified chemistry and lot documentation for that supplied product. Avoid inferring finished extrusion strength or plate quality directly from the smelter’s name, energy source or the purity of its initial metal. Those requirements need product-specific evidence.

What to verify before ordering

Use a purchase checklist covering alloy, product form, applicable specification, shipment identity and the requested sustainability documentation. Establish whether primary and recycled inputs are described separately and how the claim is allocated to the delivered material. This is a process overview, not an operating procedure or a verification of the supplier’s environmental performance.

Sources and verification

Selected facts checked 14 October 2026. Source data is reference information, not certification of supplied material.

• Hydro • Trust, transparency and transition — Public PDF excerpt; publication revision not established · checked 2026-10-14

Separate smelting from casthouse alloy manufacture

Primary metal production and later melting, holding, casting and heat treatment are different operations. Gautschi organises equipment around the latter functions. A smelter-origin claim therefore does not establish the finished product temper or dimensional acceptance. Preserve the connection from primary metal through the actual casthouse and fabrication route when documenting a product.

Source: www.hydro.com, www.gautschi.cc