(19)

(11)

EP 0 804 383 A1

(12)

(43) Date of publication: 05.11.1997 Bulletin 1997/45 (21) Application number: 96900640.0 (22) Date of filing: 22.01.1996

(51) International Patent Classification (IPC):  C01B 33/ 32( . ) C09K 8/ 16( . ) (86) International application number: PCT/GB1996/000126 (87) International publication number: WO 1996/022245 (25.07.1996 Gazette 1996/34)

(84) Designated Contracting States: DK GB NL (30) Priority: 20.01.1995 GB 19950001099 (71) Applicant: BRUNNER MOND & COMPANY LIMITED Northwich, Cheshire CW8 4DT (GB)	(72) Inventors: THORPE, Malcolm, John Cheshire CW9 8GG (GB) HUGHES, Philip, George Cheshire WA5 2AX (GB) (74) Representative: Atkinson, Peter Birch, et al  MARKS & CLERK, Sussex House, 83-85 Mosley Street Manchester M2 3LG Manchester M2 3LG (GB)