Mafic igneous rocks, such as basalt, are composed of abundant calcium- and magnesium-rich silicate minerals widely proposed to be suitable for scalable carbon dioxide removal (CDR) by enhanced rock weathering (ERW). Here, we report a detailed characterization of the mineralogy, chemistry, particle size and surface area of six mined basalts being used in large-scale ERW field trials. We use 1-D reactive transport modelling (RTM) of soil profile processes to simulate inorganic CDR potential via cation flux (Mg²⁺, Ca²⁺, K⁺ and Na⁺) and assess the release of the essential plant nutrients phosphorus (P) and potassium (K) for a typical clay-loam agricultural soil. The basalts are primarily composed of pyroxene and plagioclase feldspar (up to 71 wt%), with accessory olivine, quartz, glass and alkali feldspar. Mean crushed particle size varies by a factor of 10, owing to differences in the mining operations and grinding processes. RTM simulations, based on measured mineral composition and N₂-gas BET specific surface area (SSA), yielded potential CDR values of between c. 1.3 and 8.5 t CO₂ ha⁻¹ after 15 years following a baseline application of 50 t ha⁻¹ basalt. The RTM results are comparative for the range of inputs that are described and should be considered illustrative for an agricultural soil. Nevertheless, they indicate that increasing the surface area for slow-weathering basalts through energy intensive grinding prior to field application in an ERW context may not be warranted in terms of additional CDR gains. We developed a function to convert CDR based on widely available and easily measured rock chemistry measures to more realistic determinations based on mineralogy. When applied to a chemistry dataset for >1300 basalt analyses from 25 large igneous provinces, we simulated cumulative CDR potentials of up to c. 8.5 t CO₂ ha⁻¹ after 30 years of weathering, assuming a single application of basalt with a SSA of 1 m² g⁻¹. Our RTM simulations suggest that ERW with basalt releases sufficient phosphorus (P) to substitute for typical arable crop P-fertiliser usage in Europe and the USA offering potential to reduce demand for expensive rock-derived P.

玄武岩等镁铁质火成岩由丰富的富含钙和镁的硅酸盐矿物组成，被广泛认为适用于通过增强岩石风化 (ERW) 进行可扩展的二氧化碳去除 (CDR)。在这里，我们报告了在大规模 ERW 现场试验中使用的六种开采玄武岩的矿物学、化学、粒度和表面积的详细表征。我们使用土壤剖面过程的一维反应迁移模型 (RTM) 通过阳离子通量（Mg ²⁺、Ca ²⁺、K ⁺和 Na ⁺) 并评估典型粘壤土农业土壤中必需植物养分磷 (P) 和钾 (K) 的释放。玄武岩主要由辉石和斜长石组成（高达 71 wt%），辅以橄榄石、石英、玻璃和碱长石。由于采矿作业和研磨工艺的差异，平均粉碎粒度的变化为 10 倍。RTM 模拟，基于测量的矿物成分和 N ₂ - 气体 BET 比表面积 (SSA)，产生了介于c之间的潜在 CDR 值。1.3 和 8.5 t CO ₂ ha ^-1在基线应用 50 t ha ^-1后 15 年玄武岩。RTM 结果与所描述的输入范围相比具有可比性，应被视为对农业土壤的说明。然而，他们表明，在 ERW 环境中的现场应用之前，通过能源密集型研磨来增加慢风化玄武岩的表面积可能无法保证额外的 CDR 增益。我们开发了一种功能，可将基于广泛可用且易于测量的岩石化学测量的 CDR 转换为基于矿物学的更现实的测定。当应用于来自 25 个大型火成岩省的 >1300 玄武岩分析的化学数据集时，我们模拟了高达c 的累积 CDR 潜力。8.5 吨二氧化碳₂公顷^-1经过 30 年的风化，假设单次使用 SSA 为 1 m ²  g ^-1的玄武岩。我们的 RTM 模拟表明，含有玄武岩的 ERW 会释放足够的磷 (P)，以替代欧洲和美国典型的耕作作物磷肥的使用，从而有可能减少对昂贵的岩石衍生磷的需求。