Stone conservation in halls and bathrooms involves a wide range of natural stone materials, each with unique mineral and rock properties, as well as distinct chemical and physical characteristics. Stones can be broadly classified into three main types: igneous, sedimentary, and metamorphic rocks. Based on their chemical composition, they are further divided into carbonates and silicates. Silicate stones include granite, diabase (gabbro), syenite, and hornfels, while carbonate stones consist of marble, limestone, and travertine. Understanding the rock properties of stone helps determine its mineral and chemical composition, which in turn reveals its resistance to chemical weathering and potential for deterioration. Similarly, analyzing structural and physical properties allows us to assess how well the stone withstands physical weathering, guiding its proper use and maintenance. Modern stone applications often face chemical pollution issues such as water stains, rust spots, efflorescence, discoloration, and organic contamination. Water stains typically occur due to high water absorption rates in the stone, leading to moisture retention and long-term damage. Rust spots, on the other hand, result from the oxidation of iron components within the stone. Ferrous iron, commonly found in rocks, is unstable and reacts with oxygen in the air to form ferric oxide, causing visible discoloration. Discoloration is more common in stones with poor chemical stability, especially when installed in areas where moisture or chemicals accumulate over time. Travertine, in particular, has low chemical stability. The presence of calcium oxide makes it vulnerable to reactions with airborne pollutants like carbon dioxide, sulfur dioxide, and nitrogen oxides. These reactions can lead to yellowish-white discolorations. Additionally, during installation, volatile substances from coatings and adhesives may react with the stone, exacerbating its instability. Efflorescence occurs when stones are installed using wet methods, as alkaline materials from the bonding agents migrate to the surface. Using dry-hanging techniques can prevent this issue, along with reducing the risk of water spots. Common Stone Diseases: 1. To prevent rust spots, effective surface treatment should be applied after stone processing to stop iron-containing minerals from oxidizing and appearing on the surface. Oil-based protective agents are commonly used for this purpose. When dealing with rust stains, specialized rust removers are applied, but these are usually acidic. It’s important to test acid-sensitive stones like marble and dolomite before application, and if necessary, dilute the solution with water. 2. Water spots and wet marks are challenging to remove once formed. Prevention involves using resin-based sealants to make the stone waterproof, minimizing moisture penetration and reducing chemical reactions. For existing water spots, infiltration dyes can be used to restore the original color. "Wet marks that don't dry" remain a major challenge in international stone conservation efforts. 3. The "white haze" phenomenon, also known as efflorescence, can be prevented by applying an osmotic sealer to all six sides of the stone. When treating white haze, the stone surface should be rinsed with water to neutralize any residual chemicals. After drying, the surface and joints should be sealed. Rust removers and cleaners should use oxygen-based, mild formulas to avoid damaging the stone while removing stains like rust, tea, straw, yellow spots, and metal oxides. If the stone has severe damage, such as loss of shine, polishing may be required. A combination of Dolby Fine Powder and F66 True Light can restore the surface. These polishing powders contain fine particles of oxidizing agents like alumina or tin oxide, and they do not contain acids. Hand polishing is ideal for small areas like hotel bathrooms and kitchens, while machine polishing is suitable for larger matte surfaces. The specific steps are as follows: 1. Ensure the stone surface is completely dry and free from protective agents. If needed, clean the surface with a neutral cleaner to prepare it for polishing. 2. Apply a small amount of polishing liquid onto the stone surface, then sprinkle an equal amount of polishing powder. Use approximately half a spoon of powder and liquid per square foot (0.093 m²) of stone surface. 3. Polish the area using a 100–140 lb floor grinder or hand grinder at 1500–2500 rpm, using white nylon pads and wool pads for optimal results. Zinc ALB Flange Nut,Zinc Flange Nut DIN934,Flange Nut DIN6923,Zinc Flange Nut Din6923 Hebei Quanfang Fastener Co., Ltd , https://www.quanfangfastener.com