(19)

(11)

EP 0 750 685 A1

(12)

(43) Date of publication: 02.01.1997 Bulletin 1997/01 (21) Application number: 95911439.0 (22) Date of filing: 17.03.1995

(51) International Patent Classification (IPC):  C22C 21/ 00( . ) C22F 1/ 04( . ) C22F 1/ 00( . ) (86) International application number: PCT/GB1995/000608 (87) International publication number: WO 1995/025825 (28.09.1995 Gazette 1995/41)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU NL PT SE (30) Priority: 18.03.1994 GB 19940005415 (71) Applicant: ALCAN INTERNATIONAL LIMITED Montreal Quebec H3A 3G2 (CA)	(72) Inventors: MAHON, Gary, John Leamington Spa Warwickshire CV32 5TA (GB) MARSHALL, Graeme, John Banbury Northamptonshire OX17 2DY (GB) RICKS, Ricky, Arthur Freeland Oxfordshire OX8 8AQ (GB) (74) Representative: Pennant, Pyers, et al  Stevens, Hewlett & Perkins 1 Serjeants' Inn Fleet Street London EC4Y 1LL London EC4Y 1LL (GB)