Abstract：
Many countries have made pledges to reduce CO2 emissions over the upcoming decades to meet the Paris Agreement targets of limiting warming to no >1.5 °C, aiming for net zero by mid-century. To achieve national reduction targets, there is a further need for CO2 removal (CDR) approaches on a scale of millions of tonnes, necessitating a better understanding of feasible methods. One approach that is gaining attention is geochemical CDR, encompassing (1) in-situ injection of CO2-rich gases into Ca and Mg-rich rocks for geological storage by mineral carbonation, (2) ex-situ ocean alkalinity enhancement, enhanced weathering and mineral carbonation of alkaline-rich materials, and (3) electrochemical separation processes. In this context, Spain may host a notionally high geochemical CDR capacity thanks to its varied geological setting, including extensive mafic-ultramafic and carbonate rocks. However, pilot schemes and large-scale strategies for CDR implementation are presently absent in-country, partly due to gaps in current knowledge and lack of attention paid by regulatory bodies. Here, we identify possible materials, localities and avenues for future geochemical CDR research and implementation strategies within Spain. This study highlights the kilotonne to million tonne scale CDR options for Spain over the rest of the century, with attention paid to chemically and mineralogically appropriate materials, suitable implementation sites and potential strategies that could be followed. Mafic, ultramafic and carbonate rocks, mine tailings, fly ashes, slag by-products, desalination brines and ceramic wastes hosted and produced in Spain are of key interest, with industrial, agricultural and coastal areas providing opportunities to launch pilot schemes. Though there are obstacles to reaching the maximum CDR potential, this study helps to identify focused targets that will facilitate overcoming such barriers. The CDR potential of Spain warrants dedicated investigations to achieve the highest possible CDR to make valuable contributions to national reduction targets.
摘要：
许多国家已承诺在未来几十年内减少二氧化碳排放，以实现《巴黎协定》将变暖限制在不超过1.5°C的目标。目标是在本世纪中叶实现净零。实现国家减排目标,进一步需要数百万吨规模的二氧化碳去除(CDR)方法，需要更好地了解可行的方法。一种引起注意的方法是地球化学CDR，包括（1）将富含CO2的气体原位注入富含Ca和Mg的岩石中，以通过矿物碳化进行地质储存，(2)非原位海洋碱度增强，增强富碱物质的风化和矿物碳酸化，和(3)电化学分离过程。在这种情况下，由于其不同的地质环境，西班牙可能拥有名义上较高的地球化学CDR容量，包括广泛的镁铁质-超镁铁质和碳酸盐岩。然而,目前国内缺乏CDR实施的试点计划和大规模战略，部分原因是当前知识的差距和监管机构缺乏关注。这里,我们确定可能的材料，西班牙未来地球化学CDR研究和实施战略的地点和途径。这项研究强调了西班牙在本世纪剩余时间内的千吨至百万吨规模的CDR选项，注意化学和矿物学上合适的材料，合适的实施地点和可以遵循的潜在战略。Mafic,超镁铁质和碳酸盐岩，尾矿,飞灰,炉渣副产品，在西班牙托管和生产的海水淡化盐水和陶瓷废物具有重要意义，工业,农业和沿海地区提供了启动试点计划的机会。虽然有障碍，以达到最大的CDR潜力，这项研究有助于确定有助于克服这些障碍的重点目标。西班牙的CDR潜力需要进行专门的调查，以实现尽可能高的CDR，为国家减排目标做出宝贵贡献。
