Partitioning of In, Ga, and Sc between aqueous phase and secondary ferric minerals

酸性和中性矿山排水系统伴随着世界各地的采矿废物，通常沉淀大量的次生铁矿物。由于Fe3+与关键金属In， Sc和Ga的三价阳离子之间的晶体化学相似性，可以合理地假设这些元素进入了铁矿物的结构并在固溶体中保留在那里。在这项工作中，我建议量化Fe， In， Sc和Ga在MD系统中常见的水溶液和矿物之间的分配。这一目标将通过量热测量和涉及这些金属的端元和固溶体的热力学计算来实现。要研究的体系包括但不限于α - feooh - InOOH、α - feooh - ScOOH、α - feooh - GaOOH、FeAsO4·2H2O - InAsO4·2H2O和（H5O2）Fe2（SO4）·H2O - (H5O2)In2（SO4）·H2O。利用溶液和弛豫量热法，可以确定端元的生成焓和熵。用同样的技术，热力学混合参数将被计算为固溶体，元素的分配将被量化。常见MD矿物的合成方案将与In， Sc和Ga一起进行，并对所得相进行表征。如果它们应该是同结构的或类似于常见的铁MD矿物，它们的热力学性质也将被测量。在这项工作中获得的数据可以用来确定相(s)浓缩关键金属in， Sc和Ga强，从而可以用于经济地从采矿废物中提取这些金属。

Acid and neutral mine drainage (MD) systems accompany the mining wastes worldwide and precipitate often copious amounts of secondary ferric minerals. Because of crystal chemical similarities between Fe3+ and the trivalent cations of the critical metals In, Sc and Ga, it is reasonable to assume that these elements enter the structure of the ferric minerals and remain there in solid solutions. In this work, I am proposing to quantify the partitioning of Fe, In, Sc and Ga between aqueous solutions and minerals common in MD systems. This goal will be achieved by calorimetric measurements and thermodynamic calculations for end-members and solid solutions that involve these metals. The systems to be investigated include, but are not limited to alpha-FeOOH – InOOH, alpha-FeOOH – ScOOH, alpha-FeOOH – GaOOH, FeAsO4·2H2O – InAsO4·2H2O, and (H5O2)Fe2(SO4)·H2O – (H5O2)In2(SO4)·H2O. Using solution and relaxation calorimetry, the enthalpies of formation and entropies will be determined for the end-members. With the same techniques, the thermodynamic mixing parameters will be calculated for the solid solution, and the partitioning of the elements will be quantified. Synthesis protocols for common MD minerals will be carried out with In, Sc and Ga and the resulting phases will be characterized. If they should be isostructural or similar to the common ferric MD minerals, their thermodynamic properties will be measured as well. The data obtained in this work could serve to identify the phase(s) which concentrate the critical metals In, Sc and Ga strongly and thus could be used for economic extraction of these metals from mining waste.