铜在水蒸气相中溶解的初步实验

A Preliminary Study of the Solubility of Copper in Water Vapor

近年来地质证据和少量的实验研究证实,相当量的铜可以在气相中迁移,人们认识到铜在气相中迁移是一种重要的地球化学过程,但目前关于铜在气相中溶解反应机理的研究还相当缺乏.本文通过溶解度法,在310～350℃,压力为4.2～10MPa的条件范围内,实验研究了铜在不饱和水蒸气相中的溶解度.结果表明:水蒸气的存在大大增强了铜在气相中的溶解度;恒定温度下,铜在气相中的溶解度随着水蒸气压的增加而增大;气相中铜可能以水合物的形式存在,铜在气相中的溶解可由以下反应表述:CuClsolidm+nH2Ogas=CuClm·(H2O)gasn(m=1,2),其中水合数随着温度升高而下降,温度为310℃水合数n为～6,330℃为～5,350℃为～4.研究结果明确显示,气体溶剂H2O与铜之间的反应可大大增强铜在气相中的溶解和迁移能力.

In recent years, geological evidence and the available experimental data have shown that a significant quantity of copper can be transported in vapor. It has been recognized that the transport of copper in vapor may be an important geochemical process. But, up to now, little work has been done on the mechanisms of dissolution of copper in vapor. In this paper, the solubility of copper in undersaturated water vapor was investigated experimentally at temperatures of 310 to 350℃and pressures from 4. 2 to 10 MPa. Results of these experiments show that the presence of water vapor increases the concentration of Cu in the gas. At the same temperature, the solubility of copper increases with the increase of water vapor pressure. Copper may exist as hydrated gaseous particles in the vapor phase. The dissolution process can be described by the reaction：CuClm^solid ＋nH2O^gas=CuClm·（H2O）n^gas（m=1,2）. The hydration number decreases with increasing temperature, varying from -6 at 310 ℃, to -5 at 330 ℃ and -4 at 350℃. The results show that the interactions between gas-solvent H2O and copper significantly enhance the capacity of dissolution and transport of copper in the gas phase.