四川盆地富锶地下卤水多温相平衡与相图研究

Sr (strontium) and its compounds play very important roles in many industrial fields. At present, the main Sr resources in China are solid Sr ore deposits. Besides, the underground brines in the mineralization belts with associated Sr in the Sichuan basin are rich in Sr, K (potassium) and Br (bromine). These brines are also important liquid Sr-K-Br resources. In order to exploit and utilize Sr-K-Br resources in the underground brines in the Sichuan basin, and to understand the dissolution and crystallization behavior of Sr, K and Br salts in the underground brine-mineral system, it is necessary to systematically study the phase equilibria and phase diagrams of the above Sr-rich underground brine system. So far, there is no report on the systematic study of the phase equilibria and phase diagrams of the Sr-rich underground brines at different temperatures. Considering the compositional characteristics of Sr-rich polylayer underground brines that widely distribute in Sichuan basin, this work is designated to study the solid-liquid equilibria and phase diagrams in Sr-bearing subsystems of the six-component systems Na-K-Ca-Mg-Sr-Cl-H2O and Na-K-Ca-Mg-Sr-Br-H2O at 298 K, 323 K and 348 K. The principal tasks of this project include: (1) Measure the solubilities of salts and the densities of saturated slutions in the Sr-bearing ternary, quaternary and quinary subsystems at each temperature; (2) Determine the crystallization regularity of salt minerals at the corresponding temperatures; (3) Plot the phase diagrams of the six-component systems and its Sr-bearing ternary to quinary subsystems; (4) Use the above results to guide the comprehensive utilization of the Sr-rich underground brines, and to explain the mineralization regularity of salt minerals and relative geochemical behavours of the underground brines.

锶及其化合物在许多工业领域中都有重要用途。我国目前锶矿产资源主要为固体锶矿床，此外，四川盆地伴生锶的成矿带地下卤水含有丰富的锶，该卤水中钾溴含量也很高，是重要的液态锶钾溴资源。为了开发利用这些液态资源，揭示地下卤水-岩盐体系中锶钾溴盐的溶解和结晶规律，有必要开展富锶地下卤水体系的多温相平衡与相图研究。四川盆地富锶地下卤水体系多温相平衡的系统研究至今未见研究报道。针对四川盆地分布广泛的富锶多层地下卤水体系组成，本项目拟开展多温（298K,323K和348K）条件下六元体系Na-K-Ca-Mg-Sr-Cl-H2O和Na-K-Ca-Mg-Sr-Br-H2O中含锶子体系相平衡与相图研究，测定上述温度条件下含锶三元子体系，四元子体系及五元子体系固液相平衡的溶解度数据和密度，确定盐类矿物多温条件下的结晶规律，绘制上述含锶子体系的多温平衡相图，指导卤水的综合利用，阐明地下卤水的地球化学行为和成矿规律。

根据项目的研究计划，针对四川盆地广泛分布的富锶多层地下卤水的组成特点，本项目开展了多温（298K,323K和348K）条件下六元体系Na-K-Ca-Mg-Sr-Cl-H2O和Na-K-Ca-Mg-Sr-Br-H2O中含锶溴子体系相平衡与相图的研究，测定了上述温度条件下含锶溴三元子体系，四元子体系及五元子体系固液相平衡的溶解度数据和密度，确定了有关盐类矿物多温条件下的结晶析盐规律，绘制上述含锶溴三元子体系的平衡相图，四元子体系的干盐相图，水含量图， 以及五元子体系干盐相图，水含量图等，补充开展了部分含锶溴体系热力学性质和相平衡模拟计算的研究，补充开展了部分体系373K相平衡的研究。上述相平衡与相图的研究成果，可用于指导富锶钾溴地下卤水综合利用提取方案，预测该富锶钾溴地下卤水的地球化学平衡行为和成矿规律。依托本项目，发表了第一标注学术论文48篇，其中SCI收录英文学术论文38篇，此外发表第二标注学术论文6篇，参加了第十二届盐湖国际会议和第十八届全国化学热力学和热分析学术会议，提交会议摘要论文6篇，培养了7名硕士研究生和2名博士研究生，超额完成了项目的预期成果。