In this study, we investigated Ni2+, Zn2+, and Co2+ mineralogical incorporation and its effect on green rust transformation to magnetite. Mineral transformation experiments were conducted by heating green rust suspensions at 85 °C in the presence of Ni2+, Zn2+, or Co2+ under strict anoxic conditions. Transmission electron microscopy and powder X-ray diffraction showed the conversion of hexagonal green rust platelets to fine grained cubic magnetite crystals. The addition of Ni2+, Zn2+, and Co2+ resulted in faster rates of mineral transformation. The conversion of green rust to magnetite was concurrent to significant increases in metal uptake, demonstrating a strong affinity for metal sorption/co-precipitation by magnetite. Dissolution ratio curves showed that Ni2+, Zn2+, and Co2+ cations were incorporated into the mineral structure during magnetite crystal growth. The results indicate that the transformation of green rust to magnetite is accelerated by metal impurities, and that magnetite is a highly effective scavenger of trace metals during mineral transformation. The implications for using diagenetic magnetite from green rust precursors as paleo-proxies of Precambrian ocean chemistry are discussed.

中文翻译：

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Ni2+、Zn2+、Co2+对绿锈向磁铁矿转化的影响

在这项研究中，我们研究了 Ni2+、Zn2+ 和 Co2+ 的矿物结合及其对绿锈向磁铁矿转化的影响。在严格缺氧条件下，在 Ni2+、Zn2+ 或 Co2+ 存在的情况下，通过在 85 °C 下加热绿锈悬浮液来进行矿物转化实验。透射电子显微镜和粉末 X 射线衍射显示六方绿锈片转变为细粒立方磁铁矿晶体。添加 Ni2+、Zn2+ 和 Co2+ 可加快矿物转化率。绿锈向磁铁矿的转化与金属吸收的显着增加同时发生，表明磁铁矿对金属吸附/共沉淀具有很强的亲和力。溶解比曲线表明，Ni2+、Zn2+、和 Co2+ 阳离子在磁铁矿晶体生长过程中结合到矿物结构中。结果表明，金属杂质加速了绿锈向磁铁矿的转变，磁铁矿是矿物转化过程中痕量金属的高效清除剂。讨论了使用来自绿锈前体的成岩磁铁矿作为前寒武纪海洋化学的古代用物的意义。