- Time:Apr 06, 2023
Bulk density is the ratio of the total volume of refractory bricks to the sum of solid and pore volumes. The level of bulk density affects the porosity, strength, erosion resistance and wear resistance of refractory bricks.
The porosity is the percentage of the pore volume contained in the refractory brick to the total volume of the product. That is to say, the higher the bulk density, the smaller the porosity. Because there are also three types of pores, and the porosity of refractory bricks is closed pores, which is the apparent porosity indicated on the inspection sheet. The apparent porosity of heavy refractory bricks is generally between 10% and 28%, and the standard is less than 16% to be called low porosity products. However, as raw material resources become less and less, and the aluminum ore is harvested, the ingredients are not artificially added and fired. In the actual production process, heavy refractory bricks with less than 20% are called low-porosity bricks.
Porosity is the basic technical index of refractory bricks. Its size affects the performance of refractory bricks, especially strength, thermal conductivity, slag resistance and thermal shock resistance. As the porosity increases, the strength decreases, and low porosity is beneficial to the load softening temperature and creep properties of refractory bricks. However, the impact of porosity on thermal shock resistance is more complicated, and the thermal shock resistance is better when the porosity is within a certain range. However, if the porosity is too low, thermal shock is not good, and not all indicators are high or low.
To produce dense refractory bricks with low porosity, it is necessary to choose raw materials with low porosity. Formulate a reasonable particle gradation, rationally use the binder, fully and evenly knead, high-pressure molding and increase the firing temperature, and then extend the holding time to reduce the porosity. In an amorphous castable, adding ultra-fine powder and dispersant can form a tighter packing and obtain a product with low porosity.
The relationship between bulk density and porosity in refractory bricks is that the higher the bulk density, the smaller the porosity.
ZHENJIN REFRACTORIES has a production and office area of 7,000 square meters, 3 ultra-high temperature tunnel kilns with intelligent automatic control system, 20 sets of 400-2,500 tons of various types of CNC automatic brick presses, with an annual output of 100,000 tons of refractory materials. As one of the well-known Chinese refractory brands, Zhenjin Refractory has been established for nearly 40 years. It has rich project experience and has completed a number of large-scale high-temperature kiln masonry projects, providing cost-effective refractory solutions for many users at home and abroad. . Zhenjin Refractory goes deep into the project site to understand the actual needs, provides each user with a complete set of suitable program design, establishes a good brand image of Chinese refractory materials, and is favored by many overseas customers.
