(19)

(11)

EP 0 204 696 A1

(12)

(43) Date of publication: 17.12.1986 Bulletin 1986/51 (21) Application number: 85900154.0 (22) Date of filing: 11.12.1984

(51) International Patent Classification (IPC):  C01B 21/ 26( . ) B01J 12/ 00( . ) B01J 35/ 06( . ) B01D 46/ 10( . ) B01J 19/ 00( . ) C01G 55/ 00( . ) (86) International application number: PCT/GB1984/000428 (87) International publication number: WO 1986/003479 (19.06.1986 Gazette 1986/13)

(84) Designated Contracting States: AT BE CH DE FR GB LI LU NL SE (71) Applicant: JOHNSON MATTHEY PUBLIC LIMITED COMPANY London EC1N 8JP (GB)	(72) Inventors: BISHOP, David, Cyril Southfields London SW18 5SJ (GB) HEYWOOD, Alan, Edward St. Albans Herts AL4 9JA (GB) (74) Representative: Arthur, Bryan Edward, et al  Withers & Rogers 4 Dyer's Buildings Holborn London EC1N 2JT London EC1N 2JT (GB)