1. Acid cleaning: Hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid are mostly used in inorganic acids; citric acid, oxalic acid, and sulfamic acid are mostly used in organic acids. If sulfuric acid is used for Marble Sculpting to remove rust, sulfuric acid reacts with iron oxide to form iron sulfate, which can be dissolved in water, so rust can be removed. However, the corrosion problem of inorganic acid cleaning deserves great attention, especially for carbonates such as marble. The acid or acid radicals remaining in the micropores may damage the stone for a long time. Even if a buffer is added, it is difficult to avoid the corrosion problem. Therefore, foreign countries have tended to It should be cleaned with less corrosive organic acids or other organic substances that are easy to purify.
2. Alkali cleaning: Use the saponification and emulsification functions of alkaline chemicals to loosen and disperse dirt. Commonly used alkaline solutions are aqueous solutions of sodium hydroxide and sodium carbonate, which are mainly used to eliminate oil stains. There are two types of oil stains, saponifiable and non-saponifiable. Saponifiable oils are animal and vegetable oils, which can form soaps and dissolve in water when exposed to alkali, so they are easier to remove. Non-saponified oil stains are mineral oil stains. To clean such oil stains, emulsifiers are needed to reduce the binding force between oil stains and attachments and fall off. Common emulsifiers include trisodium phosphate and sodium silicate.
3. Active agent: Marble Sculpting is currently a common method for cleaning dirt on the surface of stone floors such as terrazzo and marble. There are two types of surfactants: ionic and non-ionic. Their molecules contain two kinds of genes, polar and non-polar. The principle of cleaning is to use the properties of surfactants to reduce interfacial tension, wetting, adsorption, emulsification, solubilization, and dispersion to make dirt molecules fall off and disperse, thereby achieving cleaning. Effect.
4. Complexing agent cleaning: Use complexing agent to complex or chelate various scale-forming metal ions to form soluble complexes for cleaning. Commonly used organic chelating agents include EDTA, DTPA and NTA. For example, EDTA (ethylenediaminetetraacetic acid) can generate polysodium salts, the common ones are disodium salts or trisodium salts, which have strong complexing ability to various scale-forming metal ions.
5. Electrochemical cleaning: With the help of the electric field force between the two polar plates, the ions or polar molecules in the dirt move according to a certain law, or promote the electrochemical reaction, so that the pollutants desorb, move or undergo chemical changes to achieve Cleaning purpose. For example, electric current can reduce the adsorption force of iron ions in the micropores of
stone sculpture, increase the diffusion coefficient, and generate electric pulses. Remove the rust on the surface of the
stone carving and at a certain depth below the surface.
6. Solvent cleaning: Marble Sculpting uses the solvent's ability to dissolve dirt. If the composition of pollutants is known, it is very effective to choose a specific solvent. For example, many organic solvents such as toluene, xylene, butyl acetate, etc. have a strong dissolving ability for grease or oil stains. It is generally faster to remove oil stains with organic solvents than to remove oil stains with lye. The disadvantage is that organic solvents are easy to volatilize. cause environmental impact.
7. Biochemical cleaning: mainly for biological pollutants. People have discovered the erosion and pollution of microorganisms on marble sculptures for a long time. The effective cleaning method is to use targeted biochemical cleaning agents for killing, dissolving, decomposing, and stripping.
