The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500 degrees C
The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500 degrees C
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DOI：
10.1016/0016-7037(95)00365-7
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发表时间：
1996-01-01
影响因子：
5
通讯作者：
Fournier, RO
中科院分区：
文献类型：
--
作者：
Bischoff, JL;Rosenbauer, RJ;Fournier, RO
本文测定了CaCl_2-H_2 O体系在380-500 ℃范围内的汽液关系（P-T-x），并导出了临界参数。结果表明，该系统的两相区是非常大的，并占据了相当大的一部分的P-T空间，在地壳中的流体循环的限制。结果还表明，该系统产生大量的HCl（高达0.1mol/kg）在气相中由液体在令人惊讶的高压下缓冲（在380 ℃下小于或等于230巴，在500 ℃下小于或等于580巴），推测是通过CaCl 2：CaCl_2 + 2 H（2）O = Ca（OH）（2）+ 2 H overdot Cl.我们解释了HCl在气相中的丰度是由于它优先于气相，而Ca（OH）_2优先于液相或固相。最近认识到的丰富的氯化钙在地壳深部卤水和他们的热液活动，使水解氯化钙的地质重要性。富钙盐水的沸腾产生大量的HCl，在中等压力下，由于液体的存在而得到缓冲。由此产生的Ca（OH）2与硅酸盐反应形成各种蚀变产物，如绿帘石，而蒸汽则产生岩石的酸蚀变，并通过其上升。
We determined vapor-liquid relations (P-T-x) and derived critical parameters for the system CaCl2-H2O from 380-500 degrees C. Results show that the two-phase region of this system is extremely large and occupies a significant portion of the P-T space to which circulation of fluids in the Earth's crust is constrained. Results also show the system generates significant amounts of HCl (as much as 0.1 mol/kg) in the vapor phase buffered by the liquid at surprisingly high pressures(less than or equal to 230 bars at 380 degrees C, less than or equal to 580 bars at 500 degrees C), presumably by hydrolysis ofCaCl2: CaCl2 + 2H(2)O = Ca(OH)(2) + 2 H overdot Cl.We interpret the abundance of HCl in the vapor as due to its preference for the vapor phase, and by the preference of Ca(OH)2 for either the liquid phase or solid. The recent recognition of the abundance of CaCl2 in deep brines of the Earth's crust and their hydrothermal mobilization makes the hydrolysis of CaCl2 geologically important. The boiling of Ca-rich brines produces abundant HCl buffered by the presence of the liquid at moderate pressures. The resultant Ca(OH)2 generated by this process reacts with silicates to form a variety of alteration products, such as epidote, whereas the vapor produces acid-alteration of rocks through which it ascends.