Among the many marbles, white marble is undoubtedly one of the most widely used stones. White marble is used in high-end and luxurious walls, floors, background walls, stairs, countertops, etc.
The simplicity and elegance of white marble, noble temperament, softness and delicacy are really addictive, and the decorative effect is even better, which is simply fantastic. Its mild tones, white snow, and pure beauty like snowflakes allow many designers to make full use and display. But at the same time, it is also the most loved and feared variety. However, white marble is hypocritical, fragile, and difficult to serve in terms of anti-fouling, which makes some users regret it, especially the fact that white marble is easy to turn yellow, which makes many people love it. Users of white marble stay away. In order to solve the quality problems such as white hair and yellow hair, we have to analyze the internal and external factors, thoroughly understand the nature of marble, and the root cause of the quality problem, and then we can solve the fundamental problem. So what causes white marble to turn yellow? How to keep the original appearance of white marble? We will help you!
The ferrous iron on the stone surface is oxidized to trivalent iron by oxygen in the air and combined with water to form hydrated ferric hydroxide, which has a very low solubility. Therefore, the yellowing pollution of the marble slab surface caused by iron is not easy to be removed. The second type of yellowing pollution of white marble slabs comes from the organic matter inside the marble, which is present in the formation of the marble, and its structure is similar to humus. These water-soluble organics present in the marble react with alkaline water and often show a brownish yellow color. Due to the existence of this organic matter inside the marble, when the marble floor or wall panel without waterproofing treatment on the back of the board is wet-pasted and installed, the alkaline water of the grout seeps through the marble and reacts with the organic matter in the marble to produce a colored product , When these colored products are brought to the stone surface by water, the second pollution of the stone surface is formed.
Even during the use period after the marble stone is installed, due to climate reasons, whenever water seeps through the cement concrete and then seeps out of the marble stone surface, it will always bring colored organic pollutants to the stone surface.
Therefore, the coverage of the waterproofing agent at the crack is very limited. During installation, scraping off the side of the specification board with cement slurry back and forth with an ash knife will also destroy the waterproof treatment that has been done. If the cement water is accidentally brought into the cracks of the marble surface when wiping the board surface, the slab surface will turn yellow sooner or later, not whether it will turn yellow.
Therefore, the effective prevention of yellowing of white marble should be a comprehensive measure. In the case that the cement floor or wall is not effectively waterproofed, the treatment of the back of the marble stone slab is particularly important. Selecting a quality-assured waterproof adhesive to waterproof the back of the board is the most important step in all measures.

In view of the fact that rust removal on white marble slabs is a professional work, it is not recommended that non-professional owners or non-professional caregivers purchase unfamiliar rust removers to remove the macular or rust spots of the marble stone, so as to avoid improper use of the marble stone permanent damage.
Causes of yellowing of white marble
1.The structure and composition of the white marble stone itself
Scanning electron microscope studies on the surface of the most common white marble found that iron minerals with particle sizes ranging from 2 microns to several hundreds of microns exist on the surface and texture of white marble, some of which are distributed on the surface of the plate, and some are enriched in the surface. texture. The oxidation of iron minerals contained in white marble is considered to be the main reason for the yellowing of marble. Since most marbles have a single and uniform color except for the texture part, when the iron-containing minerals randomly dispersed in the marble are oxidized to form yellow or brown hydrated iron oxides, defects on the board surface are formed, and the aesthetic feeling is stains, especially for white marble. The iron in white marble slabs mainly exists as ferrous sulfide, iron carbonate and magnesium iron silicate. These iron minerals are dispersed in the marble matrix or enriched in the marble texture. When these ferrous minerals on the stone surface are oxidized by oxygen in the air to form ferric iron and combine with water to form hydrated ferric hydroxide, what we often call rust is formed, commonly known as spit yellow. If no protective measures are taken, this phenomenon of marble spit yellowing will appear 8-12 months after the marble is placed. An interesting phenomenon is that this phenomenon of yellowing does not occur for marbles placed next to a heat source, such as a hot water pipe, which shows that the yellowing phenomenon of white marble is closely related to water. However, contact with water does not necessarily lead to yellowing of white marble. The thermal shock test on white marble shows that the stone samples are placed in deionized water at 15-25°C for 6 hours, and then the samples are placed in an oven at 100-110°C for 18 hours. After 20 such cycles, it was found that only the surface iron-rich samples exhibited a slight yellowing phenomenon, which was much lower than the natural yellowing phenomenon. This experimental phenomenon shows that the oxidation-reduction reaction of ferrous iron to ferric iron proceeds very slowly due to the very low conductivity of deionized water. Therefore, although the sample was immersed in water for a long time and circulated for many times, there was no obvious yellowing phenomenon. This test result shows that the yellowing phenomenon of white marble is the result of the combined action of oxidation and hydration on the ferrous minerals on the stone surface, and these two conditions are indispensable. Unlike soaking in ionized water, white marble soaked in alkaline solution is very prone to yellowing. The same stone samples were placed in alkaline water at 15-25 °C for 6 hours, and then the samples were placed in an oven at 50-60 °C for 18 hours. After 20 such cycles, the test found that all white marbles selected for the experiment had yellowed, with Carrara white being the worst. The alkaline solution is easy to make the white marble turn yellow, because in the alkaline medium, the redox potential of ferrous iron is reduced to ferric iron, and it is easily oxidized to ferric iron by oxygen in the air. The water combines to form a yellow contamination of the board surface.2.Influence of external reasons on white marble
The above two types of pollution of white marble come from the internal composition and structure of the stone, and occur under the influence of external conditions. In addition to these two types of pollution related to the composition and structure of the stone, the pollution from the outside also has the following aspects:- The yellowing caused by wear and tear is caused by the wear of the marble polished surface, and the dirt is brought into the marble surface with walking. holes, which make the surface of the white marble appear yellow.
- Yellowing caused by incorrect care The most common incorrect care is to wet the ground with a dirty mop. The dirt brought by the dirty mop accumulates in the marble, making the white marble surface polluted and yellowed.
- Yellowing caused by waxing When the marble surface is polished with wax, the thick wax layer turns yellow due to its own aging.
- Yellowing caused by crystal surface treatment The steel wool used for crystal surface treatment remains in the micropores of the polished white marble slab with tiny fine powder, which becomes the source of yellowing, especially when the marble is in a wet state for crystal surface treatment, Yellowing is more likely to occur.
- The yellowing caused by the installation process The yellowing caused by the installation is easy to be ignored, but it is widespread. Before the white marble floor or wall is installed, although the so-called six-sided waterproofing treatment is performed on the stone specification board: the bottom surface is waterproof and adhesive, and the four sides and the front are treated with penetrating waterproofing agent. If such a six-sided waterproof treatment is done very well, the quality of the selected waterproof material is also guaranteed, and theoretically, water-related yellowing should not occur again. But the fact is that even the six-sided waterproofing of the marble stone slab before installation is considered to be well done, and the yellowing of the marble slab after installation still occurs from time to time.
- The yellowing phenomenon related to the installation is mainly caused by two aspects. One is that due to the installation size, the on-site cutting destroys the original waterproof treatment of a certain side; the other possible situation is that the construction environment is dirty and the construction process The medium cement slurry falls on theslabsurface. In order to prevent the dropped cement slurry from drying out on the board surface, wipe the dropped cement slurry with a wet towel. Some dark cracks, because even if the surface of the marble slab has been treated with permeable waterproofing, it is impossible for tiny water repellent molecules to form a protective film across the cracks to shield and protect the cracks.
Prevention of yellowing of white marble
To prevent quality problems such as yellowing of white marble, the following points must be paid attention to in the process of processing and installation, so that white marble can perfectly present the beauty of decoration.- Due to the internal composition of marble.
- An effective way to prevent water from passing through the interior of the stone is to waterproof the back of the slabbefore the marble stone is installed.
- For the yellowing of white marble caused by external reasons, it can be prevented through reasonable use and maintenance.
- The practitioners of stone installation must have a certain professional foundation, understand the reasons for the yellowing of the white marble stone, have the necessary skills to install the stone, keep the construction environment clean and tidy, and avoid the yellowing of the stone caused by the installation.
Methods of dealing with yellowing of white marble
- Once the yellowing of the white marble slab is found, first find out the cause of the yellowing. Before turning the suspicion of the cause of yellowing to something to do with rust, make sure that the yellowing is not caused by aging wax or other external factors.
- After eliminating factors other than iron, white marbleneed start preparing for rust removal. At present, there are various brands of iron and yellow removers in stone care shops. Although no product discloses the basic chemical composition, most of the iron and yellow removers on the market are acidic. Due to the poor acid resistance of marble, many acidic rust removers also have great erosion on the slabsurface while removing rust. Excessive erosion of the marble slab will cause permanent damage to the slab. Therefore, when using a rust remover, remember to stick several layers of toilet paper on the surface of the stone when removing yellowing, and then pour the rust remover on the paper. Wait for about two hours, the yellow will gradually decrease, and the yellow can be removed after a few times. Professional stone care personnel generally use weakly acidic or even neutral cleaning agents to minimize damage to the marble stone.
- For the stubborn rust spots, use the paste method, that is, mix the rust remover and diatomaceous earth with water to make a paste, then apply the paste on the rust spots, cover with plastic film and use self-adhesive tape around it. Seal it, remove the dried paste after 24 hours, and collect the dissolved iron with a special cleaning agent after the removal is completed.
- The last step is very important for marble, granite, sandstone and slate tiles to remove stains, yellow and dirt, because in the process of removing rust, when iron ions diffuse to the board surface, if the iron ions diffused on the board surface are not collected cleanly , the secondary yellowing will occur soon, and the area will be wider. Of course, you can also remove yellowing at home by yourself (as shown in the picture below)