Will Silicon Carbide Abrasives Explode?

1. What is silicon carbide?

Silicon carbide, whose chemical formula is SiC, commonly known as emery, is a ceramic-like compound formed by bonding silicon and carbon.

The industrial manufacturing method of silicon carbide is to use high-quality quartz sand and petroleum coke to be refined in a resistance furnace. The refined silicon carbide blocks are crushed, acid-base washed with magnetic separation and sieving or water selection to make products of various particle sizes.

Commonly used silicon carbide abrasives have two different crystals, one is green silicon carbide, which contains more than 97% SiC, and is mainly used for grinding hard gold-containing tools. The other is black silicon carbide, which has metallic luster and contains more than 95% SiC. It is stronger than green silicon carbide, but has lower hardness. It is mainly used for grinding cast iron and non-metallic materials.

Silicon carbide abrasives are second only to diamond, cubic boron nitride and boron carbide because of their hardness performance higher than that of corundum. Therefore, it is widely used in abrasives, electronic product grinding, refractory materials, special ceramics, coating plastic modification, auto parts, military aviation, etc. It is one of the basic abrasives in the domestic tool and abrasive industry.

2. Will silicon carbide with stable performance explode?

Silicon carbide is a high-temperature resistant inorganic non-metallic material with very stable properties. In addition, the quality of silicon carbide is relatively large, it is not easy to float in the air, and the possibility of dust explosion is very, very low. What is the cause of this explosion accident?

Kong Yong, an associate professor at the School of Materials Science and Engineering of Nanjing University of Technology in China, analyzed in an interview: "The production process of quartz sand and silicon carbide is not complicated, and other flammable and explosive substances are generally not added in the production process. The reason for the explosion is the by-product-'carbon monoxide' produced in the production of silicon carbide."

According to an investigation by the domestic media Science and Technology Daily, major foreign silicon carbide manufacturers have basically achieved closed smelting, while almost all of China's silicon carbide smelting is open smelting, and most of the carbon monoxide is discharged directly. This may be one of the reasons that have caused the explosion accident.

But as far as we know, in the silicon carbide production process, only in the smelting process will produce "carbon monoxide", and some people believe that the cause of the explosion may be due to "dust explosion." When processing silicon carbide micro-powder, if the micro-powder is too fine and reaches a certain concentration at the same time, the micro-powder itself will be charged with static electricity. If it encounters sparks, even the very subtle sparks generated by mobile phones, switches, etc., there is a possibility of explosion.

Regarding the specific cause of the accident, we still need to wait for the final investigation results of relevant experts. However, this accident has once again sounded the alarm for the safety of China's abrasives industry.

Now that the global economy is slowing down, many materials companies have meager profits due to the weak demand in the downstream manufacturing market, and safety production measures are most likely to be ignored. But no matter what the environment at any time, safety production should also be placed on the most important position.