also known as open porosity. Percentage of open porosity volume and total product volume in refractory products. Unless specified, the porosity referred to in the Chinese refractory industry usually refers to the apparent porosity. Apparent porosity is an important index to evaluate the quality of refractory raw materials or products, which not only reflects the density of refractory materials, but also indicates whether the manufacturing process is reasonable. In addition to lightweight refractory products, raw materials or products with low porosity are beneficial for improving product quality, improving the mechanical strength of products, reducing the contact area and slag, and extending the Use life.

apparent porosity formulas:

Apparent porosity = (s-w/s-i) * 100

s - weight of piece soaked

w - weight of dry piece

i - weight of the piece soaked and immersed.