Causes of rust spots on stone:

The rust spots formed by the oxidation reaction of iron in the stone are the main reasons for the formation of rust spots. Iron, water, and oxygen are the three main factors that cause rust. Generally speaking, we divide rust spots into two categories according to their degree of reaction:

1) Deep rust spots. Many stone varieties, especially granite, contain a certain percentage of iron. When these iron components come into full contact with water and oxygen, they cause an oxidation reaction and rust. Stones that are particularly prone to such rust spots, such as American white hemp, Shandong white hemp (small flower), rust stone (slate), etc. In addition, the alkali in the cement reacts with the iron in the stone under the action of water to form rust spots.

2) Surface rust. In the process of mining, processing, transportation, installation, and irregular renovation of stone materials, a small amount of iron residues are left on the surface after contact with iron objects. These iron residues will oxidize with water and oxygen in the air. Rust spots are produced.

So how to deal with rust spots on stone?

The treatment of rust spots The treatment method of rust spots is mainly to use the principle of rust remover and film adsorption.

1. The stone surface is clean and dry

2. Apply rust remover evenly on the stone rust spots

3. After sticking the toilet paper, it is covered with film and sealed around.

4. After 24 hours, remove the covered film and toilet paper. If it is not removed, repeat the operation again until satisfactory.

5. Rinse with clean water and dry.

So what should we pay attention to when we carry out rust removal treatment?
Try to avoid using oxalic acid to directly clean stone rust spots, because oxalic acid simply oxidizes and reduces rust spots (Fe2+), and the oxidized and reduced iron ions still have
Instability, it is easy to re-oxidize with water and oxygen in the air to regenerate rust, and it will further expand with the flow of oxalic acid aqueous solution.
Area of ​​large rust spots. This is why the rust spots will be more and more removed when oxalic acid is used to remove rust.