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12.09.2011

Befesa Escorias Salinas, own technology for “zero discharge” in the aluminium cycle

In 1993 the factory begins its activity trying to resolve the environmental problems which exist with the spilling of salt slag. Befesa Escorias Salinas develops its own technology, aimed to the concept of "zero discharge" in the aluminum cycle.

In the process of secondary aluminum melting, sodium and potassium salts are added, which generate salt slag by retaining the oxides present in the recycling. The process key is to recover each of the fractions present in the salt slag: unrecovered aluminum and salts which return to the refined, and aluminum oxide (Paval), that is traded.

The production process begins with the reception and classification of the salt slag, then the material is mechanically grinded. This treatment makes possible to extract metallic aluminum containing the salt slag and, also, reduce the size of the particles to ensure a perfect dissolving of salts. Next stage consists of dissolving in water the grinded particles, their controlled reaction and the filtrate under vacuum to obtain the oxides. Finally, the resulting brine in the solution is crystallized by the evaporators.

Nowadays, the plant can value this remainder, as well as aluminum slags, filter dust, foundry sand and funds aluminum electrolytic cells (SPL), for which there was no technical response to treatment.

Befesa Escorias Salinas is located in the municipality of Valladolid. It employs 57 people between workers and managers, who support the treatment of 150,000 t of aluminum wastes and give technical support to other group plants in the United Kingdom and Germany. The company is certified to ISO 14001, ISO 9001, EMAS, OSHAS 18001 and it is being audited to get ISO 14064 certification.

A pile of salt slags

A pile of salt slags

Unrecovered aluminium.

Unrecovered aluminium.

Heaps of paval.

Heaps of paval.

Facilities for crystallization process.

Facilities for crystallization process.

View of Befesa Escorias Salinas.

View of Befesa Escorias Salinas.

Process diagram.

Process diagram.