Removal and prevention of yellowing of stone

Removal and prevention of yellowing of stone

People in the stone industry should have a deep understanding of the phenomenon of stone spitting, rust spots and grass rope marks. Because most people have a weak concept of stone maintenance and other well-known reasons, they often have to wait until there is a problem in the project before adopting "Which" method to remedy, why don't we take the "precaution before it happens" method to prevent the problem from happening?

First of all, we should find out the causes of yellowing and rust spots on the stone.

1. The raw stone material has a high iron content (such as American white hemp). Carbon dioxide and water in the air invade the surface of the stone and react with the iron inside the stone to form iron dioxide, which is discharged through the pores of the stone to form a macula.

2. There are residual iron filings on the surface of the stone during the sawing process. If it is not cleaned after washing with water, it will form rust after long-term storage.

3. Rust spots caused by rusting of anchor steel bars.

4. The finished stone materials are bundled and packed with straw ropes. Long-term storage or long-distance transportation may cause the stone to change color when exposed to water or moisture.

5. Stone wet hanging installation, during the curing process of cement mortar, the pigment in the mortar is discharged from the stone surface through the pores of the stone, forming stains, especially light-colored or white stone (such as Jazz White, Ascot White, Spanish Beige). This phenomenon is prone to occur.

The method of removing the yellowing phenomenon of the stone can be divided into physical removal and chemical removal.

Physical removal: Use polishing abrasive to remove the macula. However, this method is more suitable for flat stones that have not been installed, and has little meaning for installed stones or special-shaped stones, and it is laborious and costly.

Chemical removal: As we all know, the main component of rust is a mixture of iron hydroxide and ferric hydroxide. Therefore, as long as the materials and methods are correct, chemical removal is the easiest and most economical. There are mainly two traditional chemical cleaning agents, namely hydrochloric acid rust remover prepared by hydrochloric acid, corrosion inhibitor, acid mist preparation, activator, etc. and oxalic acid rust remover (a saturated solution of oxalic acid). The advantages of these two types are quick cleaning and low cost. However, if you do not rinse with water in time or do not rinse thoroughly after treatment, things are often counterproductive. The untreated ones will not turn yellow. Instead, the treated areas will "relapse" and severely damage the stone. The gloss.

At present, there are many brands of imported and domestic stone rust remover on the market. Because my country's research and development work on this product started late, the product quality and use effect need to be further improved and improved. Below we take the stone rust remover and related products produced by the German AKEMI company as an example, and put forward some of my experience and use situation to discuss with you.