Factors Affecting the Metal Recovery Yield During Induction Melting of Aluminium Swarf

• Type: Article in International Conference Proceedings Book
• Date: 2013

Authors

Puga, H (Author) Other; Barbosa, J (Author) Other; Carlos Silva Ribeiro (Author) FEUP

Conference proceedings International

Title: ADVANCED MATERIALS FORUM VI, PTS 1 AND 2

Pages: 781-+

6th International Materials Symposium (MATERIALS 2011)/15th Meeting of SPM

Guimaraes, PORTUGAL, APR 18-20, 2011

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 1 Citation

Other information

Authenticus ID: P-005-3PY

DOI: 10.4028/www.scientific.net/msf.730-732.781

Abstract (EN): Machining operations of cast parts usually generate considerable amounts of waste in the form of chips (usually 3-5% of the casting weight). Traditionally, swarf is sold to scrapers and remelters, but this option is quite expensive because the selling price is roughly 30% of the acquisition price of the commercial 2nd melt raw material. For most aluminium foundries that incorporate machining operations in their products, reusing aluminium chips as raw material for the melting stocks is perhaps the best option as waste management policy in what concerns to economical and technical aspects. Nevertheless, aluminium swarf is a low density product (0.25 kg/dm(3)) and is usually covered by a thin film of aluminium oxide and machining fluid. Melting such a product without suitable previous preparation leads to very low metal recovery rates, high energy consumption, gases and smoke generation and very low quality of the final product. During the last years, the authors have developed a high efficient and environmentally friend aluminium swarf recycling technique, using direct incorporation in aluminium melts. The influence of processing parameters, namely melt temperature and holding time, melting atmosphere, swarf briquetting pressure and melting charge composition in the metal recovery yield and dross generation was studied and characterized, and the optimal processing parameters were established. The microstructure of the final product obtained in those conditions was evaluated and is also presented. It is shown that the recycling efficiency depends on the swarf conditioning, the melting technique and the melt treatment methodology. Swarf moisture reduction, induction melting under protective atmosphere and a specially developed degassing technique were found the most important factors influencing the recycling process. By using the developed technique, cast ingots with microstructure and sanity similar to commercially available AlSi12Cu1 2nd melt raw material were successfully obtained with minimal dross formation and metal recovery rates around 90%, without using traditional salts and fluxes.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 2