Solubility controls for molybdenum in neutral rock drainage
Solubility controls for molybdenum in neutral rock drainage
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中性岩石排水中钼的溶解度控制
DOI：
10.1144/1467-7873/10-ra-043
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Beckie
中科院分区：
文献类型：
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作者：
M. Conlan;K. Mayer;R. Blaskovich;R. Beckie
研究了矿物对钼（MoO 42 −）溶解度的控制，以更好地了解钼（Mo）在中性岩石排水中的命运。持续46-110天的批实验和柱实验预测，在中性pH条件下，存在水溶液Ca和Pb时，钼铅矿（MoO 42 −）的迁移率受到钼铅矿（CaMoO 4）和钼铅矿（PbMoO 4）沉淀的限制。批实验表明，钼铅矿几乎瞬间形成，并有效地从溶液中除去铅的浓度低于检测限。粉云母的形成是动力学限制，但有能力显着降低钼浓度的方解石的存在下。观察到的初始抑制powellite形成，可能是由于缺乏可用的成核位点。在成核阶段之后，过饱和条件下的powellite形成遵循与Ca 2+和MoO 42-线性相关的二级速率表达式。柱实验提供了进一步的证据，快速纤锌矿形成和动力学限制powellite形成。从桶大小的野外细胞风化实验中取样的含铼富碳酸盐废石中也发现了powellite和wulfenite，这为这些矿物影响野外条件下Mo的流动性提供了直接证据。与Pb和Ca相反，Cu和Zn都没有形成明显的沉淀。
Mineral controls on molybdate (MoO42−) solubility were studied to better understand the fate of molybdenum (Mo) in neutral rock drainage. Batch and column experiments lasting from 46–110 days predict that molybdate (MoO42−) mobility is limited by powellite (CaMoO4) and wulfenite (PbMoO4) precipitation under neutral pH conditions with aqueous Ca and Pb present. Batch experiments demonstrate that wulfenite forms almost instantaneously and effectively removes Pb from solution to concentrations below detection limits. Powellite formation is kinetically limited, but has the capacity to significantly reduce Mo concentrations in the presence of calcite. An initial inhibition of powellite formation is observed, likely due to a lack of available nucleation sites. After the nucleation phase, powellite formation from supersaturated conditions follows a second order rate expression with linear dependence on Ca2+ and MoO42−. A column experiment provides further evidence of rapid wulfenite formation and kinetically limited powellite formation. Both powellite and wulfenite have also been identified in molybdenum-bearing carbonate-rich waste rock sampled from barrel-sized field cell weathering experiments, providing direct evidence that these minerals affect Mo mobility under field conditions. In contrast to Pb and Ca, both Cu and Zn did not form distinct molybdate precipitates.