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(11)

EP 4 573 221 A1

(12)

(43) Date of publication: 25.06.2025 Bulletin 2025/26 (21) Application number: 23761622.2 (22) Date of filing: 18.08.2023

(51) International Patent Classification (IPC):  C21B 13/00(2006.01) C25B 1/042(2021.01) C22B 5/12(2006.01) (52) Cooperative Patent Classification (CPC): C21B 13/0073; C21B 2100/66; C21B 2100/44; C21B 2100/22; C22B 5/12; C25B 1/042; C21B 2300/04; C25B 15/081 (86) International application number: PCT/SE2023/050837 (87) International publication number: WO 2024/039280 (22.02.2024 Gazette 2024/08)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA Designated Validation States: KH MA MD TN (30) Priority: 18.08.2022 SE 2250977 (71) Applicant: LUOSSAVAARA-KIIRUNAVAARA AB 971 28 Luleå (SE)	(72) Inventors: ERIKSSON, Ola 981 33 Kiruna (SE) ÅSTRÖM, Björn 981 37 Kiruna (SE) MARJAVAARA, Daniel 981 37 Kiruna (SE) TUOMAS, Göran 972 39 Luleå (SE) (74) Representative: Zacco Sweden AB  P.O. Box 5581 Löjtnantsgatan 21 114 85 Stockholm 114 85 Stockholm (SE)