Characterisation of Antimony-bearing Scorodite for Remediation of Toxic Mine Waste

自文明诞生以来，人类一直在开采金属和矿物，用于生产商品、能源和建筑。这些活动创造了巨大的财富，但也产生了大量的固体和液体废物，统称为“矿山废物”。据估计，世界各地产生的固体矿山废物的数量与全球基本地质过程所搬运的地球物质的数量相当，每年约为数十亿吨。矿山废物含有有毒的锑(Sb)，对生态系统、健康和生计构成严重危害。人类可能会因为摄入或吸入含Sb的颗粒而患上DNA损伤和肺癌等问题。接触Sb带来的风险可以通过形成吸收Sb的不溶矿物来减轻，因此它的生物可获得性很低。一种这样的矿物是蝎子石，水合砷酸铁(FeAsO4.2H20)。尽管Sb和As(砷)具有相似的化学性质，而且它们已被证明在其他矿物中相互替代，但没有人评估过蝎子石吸收Sb的潜力。我们在玻利维亚分解后的尾矿中发现了一种富含Sb的蝎石，但尚未对其吸收Sb的全部潜力进行调查。因此，本研究旨在回答“与砷相比，蝎子石对Sb的吸收效率如何？”、“富Sb蝎子石的化学和矿物学性质是什么？”以及“含Sb蝎子石的预测生物可获得性是什么？”通过回答这些问题，我们将能够设计出利用含Sb的蝎子修复受Sb污染的矿山废物的方案，从而改善世界各地数万至10万人的生活。

Since the dawn of civilization, humankind has been extracting metals and minerals for the production of goods, energy and buildings. These activities have created great wealth, but they have also produced huge quantities of solid and liquid waste, known collectively as 'mine waste'. It has been estimated that the quantity of solid mine waste generated throughout the world matches that of Earth materials moved by fundamental global geological processes, at approximately several thousand million tonnes per year. Mine wastes contain toxic antimony (Sb) in concentrations that pose serious hazards to ecosystems, health and livelihoods. Humans can develop problems such as DNA damage and lung cancer from ingestion or inhalation of Sb-bearing particles. The risks posed by exposure to Sb can be mitigated by the formation of insoluble minerals that take up the Sb so it has low bioaccessibility. One such mineral is scorodite, hydrated iron arsenate oxide (FeAsO4.2H20). No one has evaluated the potential for scorodite to take up Sb, even though Sb and As (arsenic) have similar chemical properties, and they have been shown to substitute for one another in other minerals. We have discovered an Sb-rich scorodite in decomposed mine tailings from Bolivia, but the full potential of scorodite to take up Sb has not been investigated. Therefore, this study is aimed at answering the questions 'How efficient is scorodite at taking up Sb compared to As?', What are the chemical and mineralogical properties of Sb-rich scorodites?', and 'What are the predicted bioaccessibilities of Sb-bearing scorodites?' By answering these questions, we will be able to design schemes for remediating Sb-contaminated mine wastes using Sb-bearing scorodites, and thus improve the lives of 10s to 100s of thousands of people worldwide.