Carbon capture and storage is needed to achieve deep cuts in industrial carbon dioxide (CO) emissions. One option for storing carbon dioxide is its mineralization, which is especially useful in regions with available mine tailings but no nearby geological formations suitable for carbon dioxide storage. A multi-step mineralization route has been developed at Åbo Akademi University. In this study the first step, thermal extraction of magnesium, was further improved for two magnesium-rich Finnish mine tailings as raw materials. In the experiments, the maximum yield of extracted magnesium was similar (57–65%) to that of previous studies for both tailings with a ratio of 1:3 of mine tailings to ammonium sulfate ((NH)SO), but only slightly better than with a ratio of 1:2 (55–58%). It was also found that increasing the average temperature from 410 to 460 °C slightly decreased the yield. Moreover, increasing the amount of the extracting agent, ammonium sulfate, can increase the possibility of obtaining efremovite ((NH)Mg(SO)) instead of magnesium sulfate (MgSO). This new knowledge of the effect of the reagent ratios on the formation of extraction products like efremovite could be exploited in further studies to minimize water consumption and thus energy use in ammonium sulfate recycling.

中文翻译：

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从尾矿中提取镁用于二氧化碳矿化：硫酸铵与尾矿比例对产品和产量影响的初步研究

需要碳捕获和封存来大幅削减工业二氧化碳 (CO) 排放量。储存二氧化碳的一种选择是矿化，这在有可用尾矿但附近没有适合二氧化碳储存的地质构造的地区特别有用。奥博学术大学开发了多步矿化路线。在这项研究中，以两种富镁的芬兰尾矿为原料，进一步改进了第一步，即热提取镁。在实验中，尾矿与硫酸铵 ((NH)SO) 比例为 1:3 时，两种尾矿的最大提取镁收率与之前的研究相似 (57–65%)，但仅稍好一些比例为 1:2 (55–58%)。研究还发现，将平均温度从 410 °C 提高到 460 °C 会略微降低产量。而且，增加萃取剂硫酸铵的用量，可以增加获得钾镁铁矿（(NH)Mg(SO)）而不是硫酸镁（MgSO）的可能性。关于试剂比例对钾铁矿等提取产物形成影响的新知识可以在进一步的研究中利用，以最大限度地减少水消耗，从而最大限度地减少硫酸铵回收中的能源使用。