Avalon Successfully Produces Lithium Hydroxide and Analcime Using Metso's Alkaline Leach Process

Toronto, Ontario--(Newsfile Corp. - October 9, 2025) - Avalon Advanced Materials Inc. (TSX: AVL) (OTCQB: AVLNF) ("Avalon" or the "Company") is pleased to announce the successful production of lithium hydroxide and analcime, a byproduct that can be used in the aggregate business, using Metso's proprietary Alkaline Leach Process (ALP). This achievement represents a significant milestone in Avalon's strategy to establish a sustainable, low-impact processing solution for North America's emerging lithium supply chain at its Thunder Bay Lithium Processing Facility in Ontario, Canada.

Technical Highlights:

• Avalon successfully demonstrated the conversion of lithium-bearing mineral concentrate into lithium hydroxide, confirming both high recovery and purity levels.
• The process simultaneously produced analcime, an inert, neutral, and reusable byproduct, eliminating the formation of sodium sulfate waste common in acid-based systems.
• The trial validated that no sulfuric acid or sulfate reagents are required, removing the generation of corrosive effluents and significantly reducing handling and environmental risk.
• Early assessments indicate potential reductions of up to 60% in water use and a smaller carbon footprint compared to conventional acid leach or roasting flowsheets.
• The Metso process is environmentally safe relative to other processes, produces environmentally benign byproducts like analcime, reducing effluent treatment requirements, tailings risk, and carbon emissions-a major advantage under Canada's environmental frameworks.
• This alkaline leach route consumes less energy and water than traditional acid roasting, contributing to a smaller environmental footprint and achieves close to zero discharge.
• Metso's technology directly advances the objectives of Canada's Critical Minerals Strategy, Strategic Innovation Fund, and Clean Growth Hub-facilitating the production of clean, innovative lithium hydroxide at a time when governments are seeking to establish more secure lithium supply chains and Canada faces a significant projected shortage of lithium refining capacity.

Leadership Commentary
"This is an exciting breakthrough and transformational for Avalon," said Scott Monteith, CEO of Avalon Advanced Materials. "Successfully producing lithium hydroxide using Metso's Alkaline Leach Process demonstrates that clean, efficient, and scalable lithium processing can be achieved right here in Canada. This innovation supports Avalon's commitment to building a truly sustainable battery materials supply chain for North America. Our team is most encouraged by these results as they are a clear indication of the achievable final product once in commercial production. Importantly, this process sets a new benchmark for environmental responsibility across the industry, achieving near-zero discharge - a significant advancement over existing practices."

Mark N.J. Ashcroft, P.Eng, Strategic Consultant to Avalon Advanced Materials' proposed Lake Superior Lithium facility, added: "The environmental advantages of Metso's Alkaline Leach Process are truly transformative. By eliminating strong acids and sulfates, the process produces neutral, stable residues, reduces water and energy consumption, and minimizes the overall environmental footprint. It represents a step change toward responsible resource conversion aligned with the principles of circular mineral processing."

Next Steps:
Following this successful demonstration, Avalon intends to advance to engineering scale-up, process optimization, and commercialization of its lithium hydroxide product. The Company also intends to evaluate commercial pathways for analcime use within industrial and construction applications, including its application in the cement industry. When used as a substitute for conventional additives, analcime has demonstrated the ability to reduce CO₂ emissions while improving the circular-economy profile of cement production through the diversion of by-products from landfills.

Qualified Person (QP) and NI 43-101 Disclosure
Andrew Ramcharan, P.Eng, PhD, VP, Corporate Development is the designated Qualified Person for this news release within the meaning of National Instrument 43-101 ("NI 43-101") and has reviewed and verified that the technical information contained herein is accurate and approves of the written disclosure of same.

About Metso's Alkaline Leach Process (ALP)
Metso's ALP is an acid-free, Planet Positive technology that converts lithium minerals directly to lithium hydroxide using an alkaline pressure leach approach. The process minimizes reagent use, reduces waste volumes, and generates inert byproducts such as analcime, offering a cleaner, safer, and more efficient route to battery-grade lithium production.

About Avalon Advanced Materials Inc.

Avalon Advanced Materials Inc. is a Canadian critical minerals company advancing the supply of materials essential for Canada's future. The Company is focused on developing strategic assets that support secure, domestic supply chains and long-term economic growth. Avalon is focused on vertically integrating the Ontario lithium supply chain through the development of Lake Superior Lithium Inc., Ontario's first midstream lithium hydroxide processing facility, located in Thunder Bay. This facility will serve as a vital link between northern Ontario's lithium resources and the growing EV battery manufacturing base in southern Ontario and North America. Through a joint venture with SCR-Sibelco NV, Avalon is advancing the Separation Rapids Lithium Project near Kenora, Ontario, as well as continuing exploration at its Snowbank lithium and Lilypad lithium-cesium deposits. The Company is also advancing the Nechalacho Rare Earths and Zirconium Project in the Northwest Territories. This deposit contains all light and heavy rare earth elements, as well as yttrium, zirconium, tantalum, and niobium-critical minerals used in advanced technologies across the communications, defense, clean tech, and energy sectors.

Cautionary Statement Regarding Forward-Looking Information

This news release contains "forward-looking information" within the meaning of applicable Canadian securities legislation. Generally, forward-looking information can be identified by the use of forward-looking terminology such as "add" or "additional", "advancing", "anticipates" or "does not anticipate", "appears", "believes", "can be", "conceptual", "confidence", "continue", "convert" or "conversion", "deliver", "demonstrating", "estimates", "encouraging", "expand" or "expanding" or "expansion", "expect" or "expectations", "forecasts", "forward", "goal", "improves", "increase", "intends", "justification", "plans", "potential" or "potentially", "promise", "prospective", "prioritize", "reflects", "robust", "scheduled", "suggesting", "support", "top-tier", "updating", "upside", "will be" or "will consider", "work towards", or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might", or "will be taken", "occur", or "be achieved".

Forward-looking information is subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of the Company to be materially different from those expressed or implied by such forward-looking information, including those risk factors discussed or referred to in the annual information form of the Company dated November 28, 2024 (the "AIF") under the heading "Description of the Business - Risk Factors". Forward-looking information is based on the reasonable assumptions, estimates, analysis and opinions of management made in light of its experience and perception of trends, current conditions and expected developments, as well as other factors that management believes to be relevant and reasonable in the circumstances at the date that such statements are made, but which may prove to be incorrect. Although the Company believes that the assumptions and expectations reflected in such forward-looking information are reasonable, undue reliance should not be placed on forward-looking information because the Company can give no assurance that such expectations will prove to be correct. Although the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such information. Accordingly, readers should not place undue reliance on forward-looking information. The Company does not undertake to update any forward-looking information, except in accordance with applicable securities laws.

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