(19)

(11)

EP 0 931 170 A1

(12)

(43) Date of publication: 28.07.1999 Bulletin 1999/30 (21) Application number: 97941125.0 (22) Date of filing: 24.09.1997

(51) International Patent Classification (IPC):  C22C 21/ 02( . ) C22F 1/ 047( . ) C22F 1/ 043( . ) (86) International application number: PCT/GB1997/002600 (87) International publication number: WO 1998/014626 (09.04.1998 Gazette 1998/14)

(84) Designated Contracting States: AT BE CH DE ES FI FR GB IE IT LI LU NL SE (30) Priority: 30.09.1996 EP 19960307146 (71) Applicant: ALCAN INTERNATIONAL LIMITED Montreal Quebec H3A 3G2 (CA)	(72) Inventors: RICKS, Ricky, Arthur Warwickshire CV35 0JL (GB) GATENBY, Kevin, Michael Oxon OX17 3RD (GB) CARR, Alan, Robert Daventry, Northants NN11 3SQ (GB) (74) Representative: Pennant, Pyers  Stevens, Hewlett & Perkins 1 Serjeants' Inn Fleet Street London EC4Y 1NT London EC4Y 1NT (GB)