水热制备中国紫BaCuSi2O6的条件探索及各条件产物分析研究

中国紫BaCuSi₂O₆是中国古代人工颜料硅酸铜钡的一种，是中国古代科技史中独树一帜的文明成果，代表了当时中国的科技水平和科技成就。水热合成法通过高温高压的水蒸气使那些在大气条件下不溶或难溶的物质溶解，并且重结晶来进行无机合成与材料处理，是近年来比较新兴的方法。参考前人研究，采用水热合成法，选择BaCl₂·2H₂O，CuO，Na₂SiO₃·9H₂O为原料，按照目标产物化学计量比称取，调控溶液pH、合成温度和保温时间等影响因素，制备出高纯度的中国紫。产物的物相与纯度使用XRD表征。实验结果表明，当10≤pH≤12时可生成纯度较高的中国紫，160 ℃时生成的中国紫纯度较180 ℃更高，且随着水热时间的延长，中国紫的纯度提高。考虑到绿色安全、能耗低、操作简便等因素，最终得出水热制备中国紫的最佳制备条件是pH 12，温度为160 ℃，保温时间48 h。中间产物BaSi₂O₅和Ba₄Si₆O₁₆的发现，表明在硅酸铜钡晶体的生长过程中Ba与Si先与O以不同形式结合，Cu最后参与构筑硅酸铜钡晶体。该工作提供了一种新方法用于合成纯净中国紫，可用来做文物保护修复材料；同时在中国紫的合成机理研究方面提供依据和线索，对中国古代科技史研究具有促进作用。

Study on the Conditions of Hydrothermal Synthesis of Chinese Purple BaCuSi2O6 and the Analysis of Its Products

Chinese purple BaCuSi₂O₆ is a kind of the ancient Chinese artificial pigment named barium copper silicate, representing a unique civilization achievement and a high level of science and technology in ancient China. Hydrothermal synthesis is a relatively new method in recent years to dissolve substances insoluble or sparingly insoluble under atmospheric conditions by means of high temperature and pressure water vapor, recrystallize them for inorganic synthesis and material treatment. Based on previous studies, this paper adopted the hydrothermal synthesis method, selected BaCl₂·2H₂O, CuO, Na₂SiO₃·9H₂O as raw materials, and weighed them according to the stoichiometric ratio of the target products, the influence factors such as the pH environment of the solution, the synthesis temperature and the holding time of the solution were adjusted to prepare high-purity Chinese purple. XRD characterized the phase and purity of the product. The experimental results showed that Chinese purple with higher purity could be produced at 10 ≤ pH ≤ 12, and the purity of Chinese purple at 160 ℃ was higher than that at 180 ℃, and the purity of Chinese purple increased with the extension of the hydrothermal time. It is concluded that the optimal preparation condition for the hydrothermal preparation of Chinese purple is that pH 12, the temperature reaches 160 ℃, and the holding time lasts for 48 h. In addition, the discovery of intermediates BaSi₂O₅ and Ba₄Si₆O₁₆ demonstrates that Ba and Si first combined in different forms through O during the growth of barium copper silicate crystals, and Cu finally participated in the construction of barium copper silicate crystals. To sum up, this study provides a new method for the synthesis of pure Chinese purple, which can be used to protect and restore cultural relics. It can also provide a basis and clue for the synthesis mechanism of Chinese purple, which has a considerable role in promoting the research on the history of ancient Chinese science and technology.