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Causes and Removal of Yellowing of Stone Materials

Last Updated: May 30, 2018

People in the stone industry should have a deep understanding of stone yellowing, rust spots and grass rope printing. To solve this kind of problem, first of all, we should clarify the reasons for stone yellowing and rust spotting.



1. Rust stain caused by rust of anchor

2. The finished stone products are bundled and packaged with straw ropes. When they are exposed to water or moisture, long-term storage or long-distance transportation can easily cause stone discoloration.

3. Stone wet hanging installation, cement mortar in the curing process, through the pores of the stone out of the pigment in the mortar out of the stone surface, forming stains, especially light color or white stone (such as Jazz White Marble, Ariston white, Crema marfil ), most easy to appear this phenomenon.

4. The stone material has a high iron content (such as American white granite). Carbon dioxide and water in the air invade the stone surface, react with the iron in the stone to form iron dioxide, and discharge through the capillary pores of the stone to form a yellow spot.

5. The surface of the stone during the sawing process remains iron scraps, which are not washed clean by water and stored for a long time to form rust.


The method of clearing the stone spitting phenomenon mentioned above can be divided into physical removal and chemical removal.

First, the physical removal.

The macular was rubbed off with a polishing abrasive. However, this method is more suitable for slabs that have not yet been installed. It does not make much sense for the installed stone or special-shaped stone, and it is also expensive.

Second, chemical removal.

As we all know, the main component of rust is a mixture of iron hydroxide and iron hydroxide. Therefore, as long as the materials and methods are correct, the use of chemical removal is the most convenient and economical.

There are two kinds of traditional chemical cleaning agents, namely hydrochloric acid rust remover and oxalic acid rust remover (saturated solution prepared from oxalic acid) prepared from hydrochloric acid, corrosion inhibitor, acid mist formulation, and activator. The advantages of these two types are that the quick cleaning and low cost . However, if the water is not rinsed or flushed in time after treatment, it is often counterproductive. If the untreated yellow is not treated, the treated place will be "recurring", which will seriously damage the stone and the glossiness.


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