1. Main features of lightweight refractories
As a kind of refractory materials, lightweight refractories also have certain high-temperature mechanical properties and good volume stability, and are necessary materials for various high-temperature thermal equipment. Compared with dense refractories, gas-filled lightweight refractories have high apparent porosity, low bulk density, good thermal insulation performance, which has a shielding effect on heat. Therefore, the main features of lightweight refractories are:
(1) High apparent porosity
One of the main performance indicators to measure the quality of lightweight refractories is apparent porosity. The pores are composed of the pores in the refractory material and the pores between the particles after molding. It can be divided into three types: closed pores that are closed in the product and do not communicate with the outside world; open pores that are closed at one end and communicated with the outside at the other end; and vented pores that penetrate the product and communicate with the outside at both ends. Apparent porosity refers to the ratio of the gas volume in the refractory material to the total volume of the material. The apparent porosity of dense refractories is generally less than 20%, and the apparent porosity of lightweight refractories is very high, generally 65-78%.
Next issue we will continue to introduce characteristics of light weight refractories. Please stay tuned!