The extraction of raw materials for metal hydride hydrogen storage, including rare earth elements (REEs) and magnesium, presents a complex interplay of environmental and social challenges. These materials are critical for advancing hydrogen storage technologies, but their procurement must be carefully managed to mitigate adverse effects. This article examines the impacts of mining these materials, explores responsible sourcing practices, evaluates recycling opportunities, and considers alternatives to reduce reliance on critical minerals. Geopolitical risks and lifecycle sustainability are also addressed to provide a comprehensive perspective.

Mining activities for REEs and magnesium often lead to significant environmental degradation. Rare earth elements, such as neodymium and lanthanum, are typically extracted through open-pit mining, which results in extensive land disturbance. The process generates large volumes of waste rock and tailings, which can contaminate surrounding ecosystems with heavy metals and radioactive materials. For example, the Bayan Obo mine in China, one of the largest REE producers, has been associated with soil and water pollution due to inadequate waste management. Magnesium production, primarily derived from dolomite or seawater, also carries environmental costs. Electrolytic processes used in magnesium extraction consume substantial energy, often sourced from fossil fuels, leading to high carbon emissions. Additionally, the release of sulfur hexafluoride, a potent greenhouse gas, during magnesium smelting exacerbates climate impacts.

Social impacts of mining these materials are equally concerning. Many REE deposits are located in regions with weak governance, where labor rights and environmental regulations are poorly enforced. Artisanal and small-scale mining operations, common in countries like the Democratic Republic of Congo, often involve hazardous working conditions and child labor. Local communities near mining sites frequently face displacement, loss of livelihoods, and health problems due to exposure to toxic substances. In contrast, magnesium mining tends to be more industrialized, but it still poses risks to workers and nearby populations, particularly in areas with lax safety standards.

Responsible sourcing practices are essential to address these challenges. Certification schemes, such as the Initiative for Responsible Mining Assurance, provide frameworks for ensuring ethical mining practices. Companies can adopt traceability systems to verify the origins of raw materials and avoid conflict zones or environmentally sensitive areas. For REEs, diversifying supply chains beyond dominant producers like China can reduce geopolitical risks and encourage better environmental stewardship. The European Union and the United States have initiated programs to develop domestic REE production with stricter environmental controls. Similarly, magnesium producers can transition to renewable energy sources to lower the carbon footprint of extraction and processing.

Recycling presents a viable pathway to reduce the demand for newly mined materials. Metal hydrides used in hydrogen storage can often be recovered and reprocessed, though technical and economic barriers remain. REE recycling rates are currently low due to the complexity of separating these elements from end-of-life products. However, advancements in hydrometallurgical and pyrometallurgical techniques are improving recovery efficiencies. Magnesium recycling is more established, with post-industrial scrap being widely reused in manufacturing. Expanding recycling infrastructure and incentivizing collection programs could further enhance material recovery rates.

Exploring alternatives to critical minerals is another strategy to mitigate supply chain risks. Researchers are investigating non-rare earth metal hydrides, such as those based on titanium or zirconium, which offer comparable performance with lower environmental impacts. Sodium-alanate, a lightweight hydride, has shown promise as a substitute for REE-based storage materials. Additionally, advancements in adsorption-based storage systems using porous materials like metal-organic frameworks could reduce reliance on metal hydrides altogether. These alternatives must be evaluated for scalability, cost, and performance to ensure they meet industrial requirements.

Geopolitical risks associated with REE and magnesium supply chains cannot be overlooked. China dominates the global REE market, controlling over 80% of production, which creates vulnerabilities for importing nations. Trade disputes or export restrictions could disrupt supply, as seen in past geopolitical tensions. Magnesium supply is also concentrated, with China producing nearly 85% of the world’s primary magnesium. Diversifying supply sources and investing in domestic production capabilities are critical steps to enhance resilience. International collaborations, such as the Minerals Security Partnership, aim to secure stable supplies of critical minerals through strategic alliances.

Lifecycle sustainability assessments are vital for evaluating the long-term impacts of metal hydride storage systems. These assessments must account for all stages, from raw material extraction to end-of-life disposal. Studies indicate that the environmental footprint of REE-based hydrides is heavily influenced by mining and processing, while magnesium hydrides are more energy-intensive during production. Optimizing material use, improving energy efficiency, and integrating circular economy principles can significantly reduce overall impacts. Policies promoting extended producer responsibility and eco-design guidelines can further support sustainable lifecycle management.

In conclusion, the environmental and social impacts of mining raw materials for metal hydride hydrogen storage are substantial but manageable through concerted efforts. Responsible sourcing, enhanced recycling, and the development of alternative materials are key strategies to minimize harm. Addressing geopolitical risks and adopting lifecycle sustainability approaches will ensure that hydrogen storage technologies contribute positively to the energy transition. By prioritizing these measures, stakeholders can advance hydrogen storage solutions while upholding environmental and social integrity.