The Auby smelter is a mid-scale electrolytic zinc smelter. It produces cathodes as finished products, rather than casting into ingots. Feedstock of both zinc concentrates and zinc secondaries is consumed at the plant using the RLE process to produce zinc cathode.

The Auby smelter produces zinc primarily from zinc concentrates and, to a lesser extent, recycled zinc secondary feeds. The Auby smelter can process a high percentage of secondary feed material input without adversely affecting overall plant productivity, efficiency or residue output.

The Auby smelter produces SHG cathode and some extra pure quality cathodes, the latter sold as battery-grade zinc. The site also produces by-products of sulphuric acid, Auby Leach Product (a product containing both lead and silver), copper and indium.

An indium refinery, producing 99,998% pure indium was commissioned in May 2012.

Quick facts

Technology: roast, leach, electrolysis (RLE) smelting

Products: special high grade (SHG) zinc, battery zinc, sulphuric acid, indium metal

Employees: ~350

Nyrstar Auby holds certificates for:


The Auby smelter is located in the town of Auby in the north of France, approximately 35 kilometers south of the city of Lille. It is adjacent to the Canal de la Deule, which connects to the seaports of Calais and Antwerp, and is well connected to several motorways.


The Auby plant was established in 1869 by Compagnie Royale Asturienne des Mines, in the middle of the coal mine era in order to access energy required for the industrial thermical process of refining zinc. This process remained almost unchanged until 1954, when the plant modernized its process introducing a vertical furnace.

Later in 1975, the refining technology moved from thermical to hydrometallurgic (electrolysis), which is still the current process today. Available infrastructure on site paved the way for the establishment of Indium Cement in 2007, coinciding with the plant’s integration into the Nyrstar Group.

Between 2009 and today, the plant has increased zinc production capacity and developed an indium metal refining process.

Nyrstar Auby on the map