30 June 2025

RHI Magnesita N.V.

("RHI Magnesita" or the "Company" or "Group")

DIRECTOR DECLARATION

In accordance with LR 6.4.9, RHI Magnesita announces that Janet Ashdown, Non-Executive Director, has been appointed, with effect from 1 July 2025, as a Non-Executive Director and Chair-elect of the Remuneration Committee of Synthomer Plc, a UK listed company.

For further enquiries, please contact:

Chris Bucknall, Head of Investor Relations

Tel: +43 699 1870 6490

E‐mail: [email protected]

About RHI Magnesita

RHI Magnesita is the leading global supplier of high-grade refractory products, systems and solutions which are critical for high-temperature processes exceeding 1,200°C in a wide range of industries, including steel, cement, non-ferrous metals and glass. With a vertically integrated value chain, from raw materials to refractory products and full performance-based solutions, RHI Magnesita serves customers around the world, with over 20,000 employees and contractors in 65 main production sites (including raw material sites), 12 recycling facilities and more than 70 sales offices. RHI Magnesita intends to leverage its leadership in terms of revenue, scale, product portfolio and diversified geographic presence to target strategically those countries and regions benefiting from more dynamic economic growth prospects.

The Group is listed within the Equity Shares (Commercial Companies) category ("ESCC") of the Official List of the London Stock Exchange (symbol: RHIM) and is a constituent of the FTSE 250 index, with a secondary listing on the Vienna Stock Exchange (Wiener Börse). For more information please visit: www.rhimagnesita.com