典型硫酸盐环境中砖质文物的脱盐与加固材料

中国保存有众多砖质文物建筑,目前这些文物多处于户外环境中,面临严重盐害导致的掏蚀损毁问题。因而,研究兼具脱盐功能的加固材料成为砖质文物等保护的一种创新思路,加固材料的研制和工艺技术的开发是其重点和难点,具有重大的社会需求和急迫性。为此,本工作从可溶性盐的破坏机制出发,研究出一种双组分无机加固材料,加固方法是Ba(OH)_2甲醇溶液与H_2C_2O_4、H_3PO_4乙醇溶液交替滴加,并模拟可溶性盐(NaCl、KCl、Na_2SO_4)分布的典型环境,进行加固、除盐,借助X射线衍射仪(XRD)、X射线荧光光谱仪(XRF)和无线阻尼抗钻仪等现代科学仪器,追踪盐的流出与转化过程。结果表明,本材料不仅能够加固模拟样品,同时能对最具破坏性的盐Na_2SO_4实现不可逆转化,生成重晶石的主要成分BaSO_4,加固与脱盐一次完成,是一种具有实际应用潜力的新材料。

A new procedure for desalination and reinforcement of brick cultural relics in typical sulfate environments

China has many outdoor brick cultural relics which are suffering severely from problems caused by salt damage. With a view to understanding the failure mechanism caused by soluble salts, and overcoming the problem, we have developed a two-component inorganic reinforcement material. The reinforcement method is alternate dropping of barium hydroxide solution in methanol and oxalic acid (H₂C₂O₄) and phosphoric acid (H₃PO₄) solution in ethanol and simulating typical environments of distribution of soluble salts [sodium chloride (NaCl), potassium chloride (KCl) and sodium sulfate (Na₂SO₄)]. The operating steps accomplish both reinforcement and desalination. We tracked the flowing and conversion of salts by means of various modern scientific methods such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microcopy (SEM)-Mapping and wireless damping anti-drillers. The final results show that this procedure can not only reinforce samples, but is also able to irreversibly convert Na₂SO₄ (the most destructive salt) to BaSO₄ (the main component of barite). Reinforcement and desalination can be accomplished simultaneously. In summary, this new method has great application potential.