(19)

(11)

EP 0 843 743 A1

(12)

(43) Date of publication: 27.05.1998 Bulletin 1998/22 (21) Application number: 96926475.0 (22) Date of filing: 06.08.1996

(51) International Patent Classification (IPC):  C22C 21/ 00( . ) C22F 1/ 04( . ) (86) International application number: PCT/GB1996/001895 (87) International publication number: WO 1997/006284 (20.02.1997 Gazette 1997/09)

(84) Designated Contracting States: AT BE CH DE DK FI FR GB IE IT LI LU NL SE (30) Priority: 07.08.1995 EP 19950305503 (71) Applicant: ALCAN INTERNATIONAL LIMITED Montreal Quebec H3A 3G2 (CA)	(72) Inventor: MARSHALL, Graeme, John Banbury, Oxfordshire OX17 2DY (GB) (74) Representative: Pennant, Pyers  Stevens, Hewlett & Perkins 1 Serjeants' Inn Fleet Street London EC4Y 1LL London EC4Y 1LL (GB)