Hexavalent chromium (Cr6+) is a toxic carcinogenic pollutant that might be released by the mining and processing of ultramafic rocks and nickel laterites and which requires permanent removal from the contaminated biosphere. Ultramafic material can also serve as a feedstock for the sequestration of CO2 resulting from the growth of new minerals, raising the intriguing proposition of integrated sequestration of both pollutants, CO2 and chromium, into magnesium carbonates. Such a synergistic process downstream of ore recovery and mineral processing could be an elegant proposition for more sustainable utilisation and management of the Earth's resources. We have therefore carried out an experimental and microanalytical study to investigate potentially suitable carbonate minerals. Uptake of chromium in carbonate phases was determined, followed by identification of the crystalline phases and characterisation of the local structural environment around the incorporated chromium centres. The results suggest that neither nesquehonite nor hydromagnesite have the structural capacity to incorporate Cr6+ or Cr3+ significantly at room temperature. We therefore propose that further research into this technology should focus on laboratory assessments of other phases, such as layered double hyroxides, that have a natural structural capacity to uptake both chromium and CO2.

六价铬 (Cr 6+ ) 是一种有毒的致癌污染物，可能在超镁铁岩和镍红土的开采和加工过程中释放出来，需要从受污染的生物圈中永久去除。超镁铁质材料还可以作为新矿物生长产生的CO 2封存的原料，提出了将污染物、CO 2和铬综合封存成碳酸镁的有趣主张。这种矿石回收和矿物加工下游的协同过程可能是更可持续地利用和管理地球资源的一个优雅的提议。因此，我们进行了实验和微量分析研究，以研究潜在合适的碳酸盐矿物。测定碳酸盐相中铬的吸收，然后鉴定结晶相并表征结合的铬中心周围的局部结构环境。结果表明，三水菱镁矿和水菱镁矿都不具有在室温下显着结合Cr 6+或Cr 3+的结构能力。因此，我们建议对该技术的进一步研究应侧重于其他相的实验室评估，例如具有吸收铬和CO 2的天然结构能力的层状双氢氧化物。