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(11)

EP 0 553 139 A1

(12)

(43) Date of publication: 04.08.1993 Bulletin 1993/31 (21) Application number: 91917639.0 (22) Date of filing: 07.10.1991

(51) International Patent Classification (IPC):  B01J 2/ 22( . ) B01J 21/ 16( . ) B01J 35/ 00( . ) C01B 33/ 40( . ) C01B 39/ 02( . ) B01J 21/ 06( . ) B01J 29/ 00( . ) C01B 33/ 26( . ) C01B 39/ 00( . ) C04B 33/ 20( . ) (86) International application number: PCT/GB1991/001737 (87) International publication number: WO 1992/006783 (30.04.1992 Gazette 1992/10)

(84) Designated Contracting States: BE DE FR GB NL (30) Priority: 17.10.1990 GB 19900022474 (71) Applicant: Laporte Industries Limited London WC1B 3RA (GB)

(72) Inventors: TAYLOR, Roger, Skelton 26 Bembridge Close Cheshire WA8 9AA (GB) MOBBS, David, Barry Cheshire SK9 3NN (GB) BUCK, Malcolm, Johnstone 8 Coulton Road Cheshire WA8 0DX (GB) SHAW, David, Brian 26 Franklin Close Old Hall Cheshire WA5 5QL (GB) JENNESS, Patrick 387 Liverpool Road Great Sankey Cheshire WA5 1RE (GB) (74) Representative: Green, Mark Charles  Urquhart-Dykes & Lord, 91 Wimpole Street London W1M 8AH London W1M 8AH (GB)