Beyond ore: Unveiling the hidden potential for developing nickel agromining in Brazil

Nickel (Ni) is a critical metal in the global transition to low-carbon technologies, yet conventional extraction through laterite strip-mining imposes severe environmental damage and social costs. As a biotechnological alternative, agromining uses (hyper)accumulator plants to extract and recover Ni from metalliferous substrates, linking metal recovery with sustainable land management and circular economy goals. This review provides the first comprehensive assessment of the sustainable potential of nickel agromining in Brazil, a country that hosts the world's third-largest Ni reserves (16 Mt), ∼25,000 km² of ultramafic soils, and exceptional biodiversity with more than 34,000 native plant species. Here, we summarise the current state of conventional Ni mining, the distinctive geochemical and pedological characteristics of Brazilian ultramafic soils, and the latest progress in botanical exploration, agronomic practices, and plant improvement. Although several native hyperaccumulators have been identified, no hypernickelophores (plants with >1 wt% Ni in leaves) have been discovered, highlighting the need for expanded field surveys and large-scale herbarium screening. We also underline the dual threat posed by deforestation and the expansion of mining to endemic species, many of which are still poorly understood. In parallel, we evaluate Ni recovery pathways, from biomass combustion to hydrometallurgy, emphasizing both opportunities and technical bottlenecks. Despite its promise, agromining in Brazil is constrained by limited infrastructure, fragmented research-industry-policy collaboration, and weak regulatory support. Overcoming these barriers will require long-term investment, ESG-driven policies, and public-private partnerships, which could unlock an economic potential exceeding US$1.2 billion annually, while contributing to critical metal security, climate-smart technologies, and sustainable resource governance in Brazil and beyond.