石膏溶解相变过程中流体效应的拉曼光谱研究

Raman Spectroscopic Study on the Fluid Effects in Dissolution and Phase Transition Mechanisms of Gypsum

应用拉曼光谱仪,原位观测了不同流体中石膏随温度变化的溶解相变过程。纯水流体升温过程中,石膏在170～190℃范围内发生脱水,相变为无水石膏,随后升至250℃再快速降至常温,无水石膏无变化,脱水相变过程不可逆;1mol.L-1 Na2SO4溶液升温过程中,石膏在170～190℃范围内发生脱水,相变为无水石膏,升至250℃再快速降至常温,无水石膏重新相变为含水石膏,脱水相变过程可逆。该研究反映流体效应会影响矿物溶解相变机制,研究过程中不可忽视。

Raman spectroscopic studies on the process of dissolution and phase transition of gypsum in different fluids were taken.Gypsum took phase transition to be anhydrite in the range from 170 ℃ to 190 ℃ in pure water,and no more change happened with decreasing temperature to room temperature.Gypsum took phase transition to be anhydrite in the range from 170 ℃ to 190 ℃ too in Na2SO4 solution,but anhydrite can regain to be gypsum when temperature decreases to room temperature.The process of phase transition of gypsum in pure water is not reversible,but it happens in Na2SO4 solution.The study shows that fluid effects can influence the dissolution and phase transition mechanisms of minerals and cannot be ignored.