阅读说明：本技术 一种文物表面石膏层的处理方法 (Method for treating gypsum layer on surface of cultural relic ) 是由 杨富巍 鹿瑞聪 刘妍 于 2021-09-29 设计创作，主要内容包括：本发明涉及文物保护材料领域,具体涉及一种文物表面石膏层的处理方法,先将钡物质的醇溶液以表面渗透的方法导入石膏层,然后再将蒸馏水导入并保持环境湿度进行养护,使钡物质与石膏层之间发生反应,将不稳定的石膏层转化为稳定的硫酸钡-碳酸钙混晶层。本发明方法简单,处理过程可控,在醇溶液中,钡物质不与石膏层发生作用,可以保证其良好的渗透性,从而使其充分渗透进石膏层；钡物质的醇溶液完成渗透后,导入水即可引发钡物质与石膏层之间的化学反应,从而直接转化为硫酸钡-碳酸钙混晶层,得到的硫酸钡-碳酸钙混晶层属于难溶物质,化学性质稳定,对碳酸盐岩类石质文物、壁画的石灰地仗层、古建筑砌体及石膏制品都能起到具有较好的保护作用。(The invention relates to the field of cultural relic protection materials, in particular to a method for treating a gypsum layer on the surface of a cultural relic. The method is simple, the treatment process is controllable, and in the alcohol solution, the barium substance does not react with the gypsum layer, so that the good permeability of the barium substance can be ensured, and the barium substance can fully permeate into the gypsum layer; after the alcoholic solution of the barium substance is permeated, water is introduced to initiate chemical reaction between the barium substance and the gypsum layer, so that the barium substance and the gypsum layer are directly converted into a barium sulfate-calcium carbonate mixed crystal layer, the obtained barium sulfate-calcium carbonate mixed crystal layer belongs to an insoluble substance, has stable chemical properties, and has better protection effect on carbonate rock stone cultural relics, lime ground layer of murals, ancient building masonry and gypsum products.)

1. A method for processing a gypsum layer on the surface of a cultural relic is characterized by comprising the following steps: firstly, introducing an alcoholic solution of a barium substance into the gypsum layer by a surface penetration method, then introducing distilled water, maintaining the environment humidity, and maintaining to ensure that the barium substance reacts with the gypsum layer, so that the unstable gypsum layer is converted into a stable barium sulfate-calcium carbonate mixed crystal layer.

2. The method according to claim 1, wherein the barium substance is one or more of barium methoxide, barium ethoxide and barium isopropoxide.

3. The method according to claim 1, wherein the solvent of the alcoholic solution is one or more of methanol, ethanol, and isopropanol.

4. The method of claim 1, wherein the concentration of said alcoholic barium substance solution is 5% to 20% w/v.

5. The method according to claim 1, wherein the mass ratio of the barium species introduced to the water is 1:35 to 1: 45.

6. The method of claim 1, wherein the curing conditions are an ambient humidity of 60% to 70% for a period of not less than 30 days.

Technical Field

The invention relates to the field of cultural relic protection materials, in particular to a method for treating a gypsum layer on the surface of a cultural relic.

Background

The gypsum layer is commonly found on the surfaces of carbonate rock type stone cultural relics, lime ground layer of murals and ancient building masonry, and is the result of long-term erosion of calcium element in the cultural relic preparation material by sulfur oxide type acid gas in the air. Such gypsum layers are unstable due to their high solubility, which causes severe damages such as erosion, flaking and chalking of the surface of the cultural relics. For the gypsum layer on the surface of the cultural relic, a selective removing method for the gypsum layer on the surface of the stone cultural relic and the stone material [ YangfuWei, and the like ], a national invention patent, CN201510621975.0] and surface sealing and protecting [ mechanical industry investigation and design research institute, Limited company, composite desalting and sealing and protecting material for the brick and the stone cultural relic, a preparation method and application thereof, and a national invention patent, CN201510990645.9] are two commonly used treatment methods at present. However, removal of the gypsum layer to some extent can cause changes in the appearance of the cultural relics and loss of the cultural relic's body [ Zhao Linjuan. 85-87]. The surface sealing protection is to prepare a layer of protective film on the surface of the stone cultural relic by a coating method, and the protective film can isolate the influence of external harmful environmental factors on the cultural relic. However, The compatibility of The commonly used Organic polymer protective film with inorganic stone cultural relics is poor, and The protective effect is limited because The commonly used Organic polymer protective film is corroded by factors such as light, heat and microorganisms in The open air environment [ Zhang Hui, Liu Qiang, Liu Ting and Zhang Bingjian. In essence, the instability of the gypsum layer results from its high solubility. If the solubility of the cultural relics can be reduced, the problem of protection of the cultural relics can be better solved.

Disclosure of Invention

In order to solve the problems, the invention provides a method for treating a gypsum layer on the surface of a cultural relic, which can realize the protection of a lime ground layer of a carbonate rock type stone cultural relic and a mural, an ancient building masonry and a gypsum product.

In order to achieve the purpose, the invention adopts the technical scheme that: a process for treating the gypsum layer on the surface of cultural relics includes such steps as introducing the alcohol solution of barium substance into the gypsum layer by surface osmosis, introducing distilled water, maintaining the ambient humidity, and reacting to transform the unstable gypsum layer to stable barium sulfate-calcium carbonate crystal mixture layer.

Further, the barium substance is one or a mixture of more of barium methoxide, barium ethoxide and barium isopropoxide.

Further, the solvent of the alcoholic solution is one or a mixture of methanol, ethanol and isopropanol.

Further, the concentration of the barium substance alcohol solution is 5-20% w/v.

Further, the mass ratio of the introduced barium substance to water is 1: 35-1: 45.

Further, the curing condition is that the environmental humidity is 60-70%, and the time is not less than 30 days.

The invention has the following beneficial effects: the method is simple, the treatment process is controllable, and in the alcohol solution, the barium substance does not react with the gypsum layer, so that the good permeability of the barium substance can be ensured, and the barium substance can fully permeate into the gypsum layer; after the alcoholic solution of the barium substance is permeated, water is introduced to initiate chemical reaction between the barium substance and the gypsum layer, so that the barium substance and the gypsum layer are directly converted into a barium sulfate-calcium carbonate mixed crystal layer, the obtained barium sulfate-calcium carbonate mixed crystal layer belongs to an insoluble substance, has stable chemical properties, and has better protection effect on carbonate rock stone cultural relics, lime ground layer of murals, ancient building masonry and gypsum products.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described in detail below with reference to examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

1. Preparation of gypsum layer simulation sample

The semi-hydrated gypsum and deionized water are uniformly mixed according to the mass ratio of 1:1, injected into a 2cm multiplied by 1cm mould, demoulded, maintained in a 60% relative humidity environment for 3 days, and dried in a drying oven at 50 ℃ to constant weight for later use.

2. Protective treatment of gypsum layer simulation sample

(1) Introducing 1.0ml of 10% w/v methanol-barium alcohol solution into the gypsum layer simulation sample by a surface dripping and permeating method, standing for 1 day after complete permeation, and naturally volatilizing the methanol solvent;

(2) 4.5ml of distilled water is introduced into the gypsum layer simulation sample by a surface dripping method, and the gypsum layer simulation sample is maintained in an environment with relative humidity of 60% for 30 days.

3. Simulated sample treatment effect of gypsum layer

The changes of the simulated sample of the gypsum layer before and after the treatment are shown in Table 1.

TABLE 1 Gypsum layer simulation sample treatment effect

The results show that after the gypsum layer simulation sample is treated by using the method disclosed by the invention, the porosity of the sample is reduced by 3.9%, which indicates that the test block becomes more compact; the color difference E of the sample is far lower than the allowed threshold value of 5.0 in the protection of the cultural relics, which shows that the appearance of the sample is not affected basically; the maximum conductivity of the sample in aqueous solution decreased by more than 85%, indicating a significant increase in its water stability as a result of the conversion of the highly soluble unstable gypsum layer into an insoluble stable barium sulfate-calcium carbonate mixed crystal layer.

In conclusion, the barium sulfate-calcium carbonate mixed crystal layer obtained by the invention has better protection effect on carbonate rock stone cultural relics, lime ground layer of murals, ancient building masonry and gypsum products.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.