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您的检索式：作者名="Allan PRING"
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| 1 | Mechanism and kinetics of hydrothermal replacement of magnetite by hematite显示文摘The replacement of magnetite by hematite was studied through a series of experiments under mild hydrothermal conditions(140 -220℃, vapour saturated pressures) to quantify the kinetics of the transformation and the relative effects of redox and non-redox processes on the transformation. The results indicate that oxygen is not an essential factor in the replacement reaction of magnetite by hematite, but the addition of excess oxidant does trigger the oxidation reaction, and increases the kinetics of the transformation. However, even under high O_2(aq) environments, some of the replacement still occurred via Fe^(2+) leaching from magnetite. The kinetics of the replacement reaction depends upon temperature and solution parameters such as pH and the concentrations of ligands, all of which are factors that control the solubility of magnetite and affect the transport of Fe^(2+) (and the oxidant) to and from the reaction front. Reaction rates are fast at ~200℃, and in nature transport properties of Fe and,in the case of the redox-controlled replacement, the oxidant will be the rate-limiting control on the reaction progress. Using an Avrami treatment of the kinetic data and the Arrhenius equation, the activation energy for the transformation under non-redox conditions was calculated to be 26 ± 6 kJ mol^(-1).This value is in agreement with the reported activation energy for the dissolution of magnetite, which is the rate-limiting process for the transformation under non-redox conditions. | Jing Zhao Joel Brugger Allan Pring | 2019 | Geoscience Frontiers2019，10，1： | 2 |
| 2 | 紫硫镍矿交代镍黄铁矿的水热反应机理及动力学显示文摘本工作首次在实验室条件下对浅生区紫硫镍矿(Ni,Fe)3S4交代镍黄铁矿(Ni,Fe)9S8水热反应的机理及动力学进行了研究。起始反应矿物采用高纯自然镍黄铁矿,合成纯镍黄铁矿或合成镍黄铁矿-磁黄铁矿集合体。反应pH值采用0.2M醋酸-醋酸纳缓冲溶液控制在3~5的范围内。反应进程由X-射线衍射物相定量分析及扫描电镜观察进行跟踪。结果表明,当反应温度恒定在80℃时,交代20(4)%的镍黄铁矿需792h。相同条件下加入少量H2S可将反应速率提高一倍。当反应在125℃饱和蒸汽压水热环境下进行时,完全交代纯镍黄铁矿需约168h。此过程由于磁黄铁矿的存在而被催化,交代集合体中的镍黄铁矿仅需68h,进一步反应磁黄铁矿被交代成白铁矿。磁黄铁矿的催化作用可能源于溶解产生的微裂纹加速了流体的传质过程。当反应温度升高至145℃时,速率反而下降,不遵循Arrhenius经验规律。动力学分析得80℃速率常数介于5.8×10-8~3.0×10-7/s之间,125℃及145℃速率常数分别介于2.8×10-6~2.08×10-5/s及1×10-6~5.1×10-6/s之间,远高于同温度下固相扩散反应的速率常数,表明该反应在地质时标上为一快速反应。此外,用背散射电子显微技术对矿物表面形貌进行了分析,发现交代产物紫硫镍矿具有颗粒细小及存在微裂纹等特征,与自然界浅生矿床中的紫硫镍矿非常相似;电镜实验还表明该交代作用是一个典型的耦合溶解-再沉淀反应。其耦合机制的驱动力可能与反应界面处微空隙对流体饱和度的控制有关。 | 夏方 陈国荣 Allan PRING Joёl BRUGGER Yung NGOTHAI Brain O'NEILL Chris COLBY Christophe TENAILLEAU 王海鹏 杨云霞 | 2007 | 地质学报2007，81，10： | 2 |
| 3 | Trace and minor elements in sphalerite: A LA-ICPMS study显示文摘 | Nigel J. Cook Cristiana L. Ciobanu Allan Pring William Skinner Masaaki Shimizu Leonid Danyushevsky Bernhardt Saini-Eidukat Frank Melcher | 2009 | Geochimica et Cosmochimica Acta2009，，16： | 1 |
| 4 | Trace and minor elements in sphalerite: A LA-ICPMS study显示文摘 | Nigel J. Cook Cristiana L. Ciobanu Allan Pring William Skinner Masaaki Shimizu Leonid Danyushevsky Bernhardt Saini-Eidukat Frank Melcher | 2009 | Geochimica et Cosmochimica Acta2009，，16： | 1 |
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