To understand the calculation method of the density of refractory castables, we must first understand what stomata are. There are three types of stomata: The ones that are closed on one side and the other side communicate with the outside are called open pores, and those that are closed in the sample and do not communicate with the outside are called closed pores. The pores, which penetrate through several sides of the sample, are called through pores. The total porosity, the true porosity, refers to the percentage of the total volume of the pores in the sample to the total volume of the sample; in general, the through pores are combined with open pores, and there are fewer closed pores and it is difficult to directly measure. Therefore, the porosity is expressed by the open porosity, that is, the apparent porosity. The apparent porosity refers to the percentage of the total volume of open pores in the sample to the total volume of the sample.
Bulk density refers to the ratio of the amount of pouring material to the total volume of the sample after drying, that is, the ratio of the amount of pouring material to the total volume of the porous body, expressed in Kg/m3 or g/cm3. Obvious porosity and bulk density are one of the basis for controlling the amount of castable in refractory castable construction. The two performance indexes can be measured with the same sample.
The following are the bulk density and apparent porosity of commonly used refractory castables.
CA-50 cement high alumina castable 2.3--2.6g/cm3 17-20
CA-50 cement clay castable 2.2—2.35g/cm3 18-22
clay combined high alumina castable 2.25-2.45g/cm3 16-21
Low cement high alumina castable 2.4--2.7g/cm3 10-16
Ultra low cement high alumina castable 2.3--2.6g/cm3 10-16
CA-70 cement corundum castable 2.7--3.0g/cm3 12-16
Water glass clay castable 2.10--2.35g/cm3 15-19
High alumina phosphate castable 2.3--2.7g/cm3 17-20
Aluminum phosphate high alumina castable 2.3--2.6g/cm3 16-20
The following is a brief introduction to the density of low-cement castables.
Low-cement castables use calcium aluminate cement as a binder. Castables with a CaO content of less than 2.5% are generally called low-cement castables. Different from traditional castables: low-cement castables are used to replace most or all of the high-alumina cement with the same or similar chemical composition of the main material and have the same or similar cohesive and combined ultra-fine powder (particle size less than 10 microns) to optimize the particle gradation, micro-powder, It is formulated by adding a small amount of dispersant (water reducing agent) and an appropriate amount of retarder and other compound additives to factors such as particle shape.
The density of clay-based low-cement refractory castable is about 2.26g/cm³
The density of high-aluminum low-cement refractory castable is about 2.3~2.6g/cm³
The density of corundum-based low-cement refractory castable is about 2.65~2.9g/cm³
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