Mineralogically complex feedstocks, including kimberlite, serpentinite, and wollastonite skarns, have vast capacities to sequester carbon dioxide (CO₂) through enhanced rock weathering and CO₂ mineralization. However, only a small reactive fraction of these feedstocks will be accessible for carbon dioxide removal at Earth's surface conditions. We have developed a new method to evaluate the reactivity of mineral feedstocks that consists of a batch leach test using CO₂ coupled with total inorganic carbon (TIC) analysis to quantify easily extractable Mg and Ca from non-carbonate (desirable) cation sources. Kimberlite residues from the Venetia Diamond Mine (South Africa), serpentinites, wollastonite skarn, and brucite ore were tested and the results were compared to those from commercial ammonium acetate (NH₄OAc) leach tests. A strong correlation (R² = 0.99) between leached Ca and TIC showed that carbonate minerals (e.g., calcite in kimberlite) are a substantial and undesirable source of easily extractable cations that must be excluded in calculating CO₂ sequestration potential. Silicate dissolution (e.g., serpentine) was inferred from the strong positive correlation (R² = 0.94) between Mg and Si concentrations leached from kimberlites and serpentinites. Strong correlations between leached Ca and Si were only detected for wollastonite skarns, whereas Mg leaching from samples with high abundances of brucite showed weak or no relationship to TIC or Si. The ability to distinguish between sources (non-carbonate versus carbonate) of easily extractable cations is necessary to accurately assess CO₂ sequestration potential. The maximum CO₂ storage capacity of the Venetia kimberlites was 268–342 kg CO₂/t, and our leach test estimated an accessible potential in the range of 3–9 kg CO₂/t when only accounting for non-carbonate sources. Our CO₂ batch leach test is useful to evaluate the reactivity of mineralogically complex feedstocks at Earth's surface conditions for the purpose of carbon dioxide removal.

矿物结构复杂的原料，包括金伯利岩，蛇纹石和硅灰石矽卡岩，具有通过增强岩石风化和CO ₂矿化来隔离二氧化碳（CO ₂）的强大能力。但是，在地球表面条件下，这些原料中只有一小部分可用于去除二氧化碳。我们已经开发了一种评估矿物原料反应性的新方法，该方法包括使用CO ₂的分批浸出试验结合总无机碳（TIC）分析来量化易于从非碳酸盐（理想）阳离子源中提取的Mg和Ca。测试了来自Venetia钻石矿（南非），蛇纹岩，硅灰石矽卡岩和水镁石矿石中的金伯利岩残余物，并将结果与​​商业醋酸铵（NH ₄ OAc）浸出试验的结果进行了比较。 浸出的Ca与TIC之间具有很强的相关性（R ² = 0.99），表明碳酸盐矿物（例如金伯利岩中的方解石）是易于提取的阳离子的重要且不理想的来源，在计算CO ₂螯合势时必须排除这些来源。从强正相关推断硅酸盐溶解（例如蛇纹石）（R ² = 0.94）从金伯利岩和蛇纹岩中浸出的Mg和Si浓度之间。仅从硅灰石矽卡岩中检出了浸出的Ca和Si之间的强相关性，而从高含量的水镁石样品中浸出的Mg与TIC或Si的关系很弱或没有。区分容易提取的阳离子的来源（非碳酸盐和碳酸盐）的能力对于准确评估CO ₂螯合潜力是必需的。Venetia kimberlites的最大CO ₂储存容量为268–342 kg CO ₂ / t，我们的浸出试验估计，仅考虑非碳酸盐来源时，可利用的潜力在3–9 kg CO ₂ / t范围内。我们的CO ₂ 分批浸出试验可用于评估矿物复杂原料在地球表面条件下的反应性，以达到去除二氧化碳的目的。