(19)

(11)

EP 0 408 549 A1

(12)

(43) Date of publication: 23.01.1991 Bulletin 1991/04 (21) Application number: 88907847.0 (22) Date of filing: 12.09.1988

(51) International Patent Classification (IPC):  C01B 33/ 037( . ) (86) International application number: PCT/SE1988/000469 (87) International publication number: WO 1989/002415 (23.03.1989 Gazette 1989/07)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI NL SE (30) Priority: 15.09.1987 SE 19870003561 (71) Applicant: CASCO NOBEL AB S-100 61 Stockholm (SE)	(72) Inventors: MELLSTRÖM, Rolf S-840 10 Ljungaverk (SE) ANDERSSON, Olaus S-840 10 Ljungaverk (SE) HLUND, Göran S-840 10 Ljungaverk (SE) JOHANSSON, Ingemar S-840 21 Erikslund (SE) (74) Representative: Schöld, Zaid  Eka Nobel AB Patent Department Box 11556 S-100 61 Stockholm S-100 61 Stockholm (SE)