盐害是多孔材质文物中较普遍、 较严重的病害。 可溶盐在复杂的水盐活动中会持续对文物本体造成破坏。 精确鉴别文物中可溶盐的种类是研究文物盐害机理、 开展盐害治理、 设计开发相应的文物保护材料的必要前提。 为此, 建立了一套文物中可溶盐提取和鉴定的操作流程, 通过离子色谱（IC）、 光学显微镜、 红外光谱（FTIR）、 拉曼光谱（Raman）、 扫描电子显微镜（SEM-EDS）等多种技术方法的优化组合, 实现对文物中常见可溶盐的精确鉴别。 研究表明, NaCl可通过IC（浸出液中含有Na+、 Cl-）、 显微观察（立方晶体）以及SEM-EDS（主要含有Na、 Cl元素）进行鉴别; CaCl2可通过IC（Ca2+、 Cl-）以及SEM-EDS（Ca、 Cl元素）进行鉴别; Na2SO4可通过IC（Na+、 SO2-4）、 显微观察（丛状或团簇状晶体）、 FTIR（主峰1 134、 637、 615 cm-1）、 Raman（主峰993 cm-1）以及SEM-EDS（Na、 S、 O元素）进行鉴别; CaSO4可通过IC（Ca2+、 SO2-4）、 显微观察（六棱柱状、 针状或棒状晶体）、 FTIR（1 144、 668、 603 cm-1）、 Raman（1 017 cm-1）以及SEM-EDS（Ca、 S、 O元素）进行鉴别; NaNO3可通过IC（Na+、 NO-3）、 FTIR（1 379、 1 353和837 cm-1）、 Raman（1 071 cm-1）以及SEM-EDS（Na、 N、 O元素）进行鉴别; Ca(NO3)2·4H2O可通过IC（Ca2+、 NO-3）、 FTIR（1 437、 1 367、 1 047 cm-1）、 Raman（1 059 cm-1）以及SEM-EDS（Ca、 N、 O元素）进行鉴别。 另外, 通过显微形貌观察可直接鉴别出立方块状的NaCl, 丛状、 团簇状或薄片状的Na2SO4, 以及六棱柱状、 针状或棒状的CaSO4。 CaCl2、 NaNO3、 Ca(NO3)2·4H2O具有强吸湿性, 暴露在室温下有快速潮解现象, 据此可判断结晶盐中是否含有强潮解盐。 该鉴别技术组合使用常见仪器设备, 成本较低, 简单易操作, 结果可靠, 可用于不同材质文物中可溶盐的精确鉴定, 具有较好的应用推广前景。

Salt damage is a common and serious disease in porous cultural relics. Complex water and salt activities make the salt continuously destroy the cultural relics. Accurate identification of soluble salts in cultural relics is anessential prerequisite for studying the salt damage mechanism and management, and the design and development of appropriate protection materials for cultural relics. In this study, an operational procedure for the extraction and identification of soluble salts in cultural relics was established. Through the optimization of ion chromatography (IC), optical microscopy, infrared spectroscopy (FTIR), Raman spectroscopy (Raman), and scanning electron microscopy (SEM-EDS), accurate identification of common soluble salts in cultural relics has been achieved. The research shows that NaCl can be identified by IC (Na+ and Cl- in leachate), microscopic observation (cubic crystal) and SEM-EDS (mainly containing Na and Cl elements); CaCl2 can be identified by IC (Ca2+, Cl-) and SEM-EDS (Ca, Cl elements); Na2SO4 can be identified by IC (Na+, SO2-4), microscopic observation (clumped or cluster crystal), FTIR (main peaks 1 134, 637, 615 cm-1), Raman (main peak 993 cm-1) and SEM-EDS (Na, S, O elements); CaSO4 can be identified by IC (Ca2+, SO2-4), microscopic observation (hexagonal prism, needle or rod-shaped crystal), FTIR (1 144, 668, 603 cm-1), Raman (1 017 cm-1) and SEM-EDS (Ca, S, O elements); NaNO3 can be identified by IC (Na+, NO-3), FTIR (1 379, 1 353, 837 cm-1), Raman (1 071 cm-1) and SEM-EDS (Na, N, O elements); Ca(NO3)2·4H2O can be identified by IC (Ca2+, NO-3), FTIR (1 437, 1 367, 1 047 cm-1), Raman (1 059 cm-1) and SEM-EDS (Ca, N, O elements). In addition, cubic NaCl, clumped, cluster or flake Na2SO4, hexagonal prism, needle or rod-shaped CaSO4can be directly identified through microscopic morphology observation. CaCl2, NaNO3 and Ca(NO3)2·4H2O have strong hygroscopicity and have rapid deliquescence when exposed to room temperature, according to which it can be determined. This identification technology combines common instruments, has relatively low cost, is simple and easy to operate, and has reliable results. It can be used to accurately identify of soluble salts in cultural relics of different materials, with good prospects for application and promotion.