Sesame gray stone is exposed to wind and sun every day on the roadside, often causing damage. Rust spots are a very common type of damage. Here are some tips for cleaning rust spots.
There are usually two types of rust spots on sesame gray stone. One is caused by external rust pollution, such as rust flowing down from advertising stands on granite surfaces washed away by rainwater; Another way is that when granite is invaded by water, iron compounds further oxidize and diffuse in the stone. For the former, if you want to achieve the desired rust removal effect, you can generally use some weakly acidic rust removers. For the latter, if only the rust spots on the surface of the stone are removed, then in damp conditions, due to its own reasons, these stones will reappear with rust spots. For this situation, it is advisable to choose composite rust removers with better performance. This is because using such rust removers can not only remove rust spots, but also convert iron oxides into some inert components, which can prevent them from rusting again. Because excessive moisture is the main cause of rust on stone, it is necessary to promptly waterproof the stone after removing the rust spots.
Try to avoid using oxalic acid to directly clean stone rust spots, as oxalic acid is only a simple oxidation-reduction rust spot. Iron ions are still unstable after oxidation-reduction and can easily oxidize with water and oxygen in the air to form rust spots again. With the flow of oxalic acid aqueous solution, the area of rust spots will further expand. Due to the different compositions of marble and granite, their properties are also different. The main component of marble is alkaline calcium carbonate, while the main component of granite is acidic silicon dioxide. Therefore, when using rust removers, marble rust removers should be distinguished from granite rust removers. Sesame gray granite rust remover cannot be used to treat marble rust spots.
When choosing rust remover, try to choose high-quality products. In addition to the acidic component, a good rust remover also needs an appropriate amount of additives to maintain the stability of iron ions during the redox process. After treating rust spots with this rust remover, even without protective treatment, they can be maintained for a long time without recurrence. In contrast, some rust removers cannot maintain the stability of iron ions during the oxidation-reduction process and have a high repetition rate, only as a mixture of acids.

The treatment of surface rust spots only requires applying rust remover to the surface. Sometimes, surface grinding and polishing methods can be used, and the treatment of deep rust spots requires a fixed dosage and reaction time, which can be relatively more complex. To achieve the expected effect, it is sometimes necessary to reuse. After using rust remover to construct the stone, it is necessary to clean the stone with water again and use high-quality stone curing agent for protection after drying. The purpose is to prevent the recurrence of oxidation reactions, so the residues after oxidation reactions are removed.