Thermodynamics of the natural assemblages of Ni-Co-Mn-Cu-Fe-Zn arsenates

提出的工作的第一个目标是确定从Jáchymov中选定的次生矿物的合成类似物的热力学性质。这些矿物是：1)镁辉石组矿物[M（AsO3OH）·H2O矿物，M = Mn、Zn、Co、Mg、Ca或Ca/Mn]； 2)砷酸盐组矿物[M3(AsO4)2·8H2O，其中M = Ni、Co、Zn、Mg、Mn、Fe和Cu]； 3)酸性砷酸铁硫酸盐硫酸盐[Fe（AsO2(OH)2）·5H2O]和铁辉石[Fe2(AsO4)(SO4)（OH）·5H2O]。将从这些组中选择矿物进行合成，并通过结合量热技术确定其热力学性质。该选择是基于对历史悠久的Ag-Ni-Co-U（-As-Bi）矿床Jáchymov （Joachimsthal）地下空间的实地工作。历史悠久的Ag-Ni-Co-U（-As-Bi）矿床Jáchymov的地下空间为我们在之前的工作中研究过的许多当地环境提供了一个自然实验室。在拟议的工作中获得的数据将用于了解和数值模拟次生矿物的形成。该项目的第二个目标是扩展在0-200℃温度之间的二次矿物的大型热力学数据集的适用性。这项工作将通过结合德拜-爱因斯坦函数来拟合现有的数据集，使用适当的软件（SUPCRT）计算不同温度下的溶解度常数并将结果制表来实现。这项工作将允许整个地球化学界使用这些数据来模拟涉及许多次生砷酸盐、硫酸盐或氧化物的任何过程。

The first goal of the proposed work is the determination of thermodynamic properties of synthetic analogs of selected secondary minerals from Jáchymov. These are i) minerals of the krautite group [M(AsO3OH)·H2O minerals with M = Mn, Zn, Co, Mg, Ca, or Ca/Mn], ii) arsenates of the vivianite group [M3(AsO4)2·8H2O, where M = Ni, Co, Zn, Mg, Mn, Fe, and Cu], and iii) acidic ferric arsenate-sulfates kaatialaite [Fe(AsO2(OH)2)·5H2O] and sarmientite [Fe2(AsO4)(SO4)(OH)·5H2O]. Selected minerals from these groups will be synthesized and their thermodynamic properties determined by a combination of calorimetric techniques. The selection is based on the field work in the underground spaces in a historical Ag-Ni-Co-U(-As-Bi) ore deposit Jáchymov (Joachimsthal). The underground spaces of the historical Ag-Ni-Co-U(-As-Bi) deposit Jáchymov offer a natural laboratory with many local environments which we investigated in our previous work. The data obtained within the proposed work will be used to understand and numerically model the formation of the secondary minerals.The second goal of the project is the extension of applicability of a large thermodynamic data set for secondary minerals for temperatures between 0-200 oC. This work will be achieved by fitting the already existing data sets by a combination of Debye-Einstein functions, calculating the solubility constants at various temperatures using the appropriate software (SUPCRT) and tabulating the results. This work will allow the entire geochemical community to use the data to model any process involving many secondary arsenates, sulfates, or oxides.