Silicon Carbide Powder Burning, Do You Believe?

Recently, the domestic many large media are reporting the news of the fire in a silicon carbide warehouse and picked up by numerous websites. But some experts have questioned. Silicon carbide can be used as refractory material, whose chemical property is very stable. How are these happening? Finally, the author understood the cause of the incident and would like to share with readers after communicating with silicon carbide production enterprise.

First of all, we should know some main business firstly of the factory where the fire happened. According to the information provided by the insiders, the company is mainly engaged in recycling sand processing business, and stacking of silicon carbide materials in the warehouse are likely to be recycling sand instead of silicon carbide powder. If it is recycling pure silicon carbide powder, silicon carbide is very different to burn as the refractory. Therefore, it is obviously not scientific that silicon carbide powder can burn.

Next, we will have a look at why reused sand caught fire. Actually, untreated reused sand is mixed with a large number of impurities, such as silicon powder, silicon carbide powder, pollutants, cutting fluid residue and so on. The culprit here may be the monocrystalline or polycrystalline silicon powder, that is to say, it produces the superfine silicon crystal powder when cutting silicon wafers. The ultrafine silicon powder can react with water and will release the heat. Si+4H2O=H4SiO4+2H2↑, from the point of chemical equation, we can understand the real cause of the fire. Hydrogen gas accumulation is very dangerous. Although hydrogen gas ignition energy is small, it can easily catch fire, and even the small spark is also easy to catch fire.

So we are clear about the reason of the fire now. It is not like factory employees said “Silicon carbide combustion generates silicon oxide and silicon oxide will react in water, which can produce strong reaction and generate the hydrogen gas. From the explosion on the scene, it is likely that silicon oxide met water and then exploded in a small rang". Silicon carbide and silicon oxide both have very stable chemical properties and can be used for refractory material. It is not possible to burn for silicon carbide under natural conditions, and silicon oxide is also difficult to react with water.