南翼山深部卤水蒸发结晶过程中铵、钾共析行为研究  

Co-precipitation of ammonium and potassium in carnallites in the process of evaporation of deep brine in Nanyishan structure

作　　者：高丹丹[1,2] 李东东 冯海涛[1,2] 李武 董亚萍[1,2] GAO Dandan;LI Dongdong;FENG Haitao;LI Wu;DONG Yaping(Key Laboratory of Green and High-end Utilization of Salt Lake Resources,Xining,Qinghai 810008,China;Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources,Xining,Qinghai 810008,China;Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province,Xinning,Qinghai 810008,China)

机构地区：[1]中国科学院青海盐湖研究所盐湖资源绿色高值利用重点实验室,青海西宁810008 [2]青海省盐湖资源综合利用工程技术中心,青海西宁810008 [3]青海省盐湖资源化学重点实验室,青海西宁810008

出　　处：《地质学报》2024年第10期2968-2977,共10页Acta Geologica Sinica

基　　金：青海省自然科学基金项目(编号2024-ZJ-901)资助的成果。

摘　　要：高铵卤水的蒸发过程中通常会形成掺杂NH+4的钾石盐和光卤石等含铵盐类。固溶体或复盐被用于解释铵和钾在光卤石中的共析出现象。然而,NH_(4)^(+)进入光卤石矿床的机制一直未得到更好的理解。重新审视这一问题,对于深入了解蒸发岩中NH+4的地球化学行为具有重要意义。本研究从相平衡实验和热力学建模方面重新审视了KCl+NH_(4)Cl+MgCl_(2)+H_(2)O四元体系中光卤石(推测是KMgCl_(3)·6H_(2)O、NH_(4)MgCl_(3)·6H_(2)O、K_(2)NH_(4)Mg_(3)Cl_(9)·18H_(2)O、KNH_(4)Mg_(2)Cl_(6)·12H_(2)O和光卤石型固溶体)与水相的平衡。此外,对南翼山地下卤水进行室温蒸发实验,并与相平衡结果进行比较。本文模拟和实验结果均显示在298.15 K时该体系会形成富钾和富铵两种类型的光卤石固溶体,不形成纯盐相KCl、NH_(4)Cl及复盐相KMgCl_(3)·6H_(2)O和NH_(4)MgCl_(3)·6H_(2)O。南翼山卤水实际蒸发实验、相平衡实验和模型模拟结果一致,表明南翼山深部卤水蒸发过程形成了富含铵的光卤石固溶体,而不是新的光卤石型复盐。本文研究结果对于南翼山深部卤水钾资源开发利用提供了基础理论支撑。Ammonium-containing salts,e.g.NH_(4)-doped sylvite and NH_(4)-doped carnallite,usually form during the evaporation of brines with high NH_(4)^(+)content.Solid solutions or double salts have been proposed for interpreting the co-precipitation phenomenon of ammonium and potassium in carnallite.However,the mechanism of NH_(4)^(+)into carnallite deposit has never been well understood.Revisiting the problem critically is of importance for deeply understanding the geochemistry behavior of NH_(4)^(+)in evaporites.In this study,we revisited the equilibrium of carnallite(possibly KMgCl_(3)·6H2O,NH_(4)MgCl_(3)·6H2O,K_(2)NH_(4)Mg_(3)Cl_(9)·18H2O,KNH_(4)Mg_(2)Cl_(6)·12H_(2)Oand carnallite-type solid solutions)with aqueous phase in the quaternary KCl+NH_(4)Cl+MgCl_(2)+H_(2)Osystem from experimental and thermodynamic modeling.Besides,the evaporation experiments of the Nanyishan oil-field brine were performed at room temperature to make a comparison with the phase equilibrium results.Our results support the formation of two types of carnallite solid solutions(K-enriched and NH_(4)-enriched).There is no pure KCl,NH_(4)Cl,KMgCl_(3)·6H_(2)Oand NH_(4)MgCl_(3)·6H_(2)Oin the quaternary system at 298.15 K.Our brine evaporation results also agree with the experimental and thermodynamic modeling results of phase equilibrium,indicating the formation of a NH_(4)-enriched carnallite solid solution instead of new carnallite-type double salt.

关 键 词：深部卤水 铵 钾 光卤石 固溶体 

分 类 号：TS392[轻工技术与工程]