It is highly essential to measure pore size and its distribution to get the desired optimum properties in any refractory brick. Actually ‘pore size’ and ‘pore size distribution’ are two different things. First, let us discuss the difference between these two terms. The ‘pore size’ is a measure of the diameter of the largest pore whereas; the ‘pore size distribution’ is a measure of the range of pore sizes. The range of pore sizes can be normally distributed, and the spread can be quite narrow (e.g. the ratio of largest to smallest may be less than 2). On the other hand, pore size distribution can be very heterogeneous. In the case of large spreads and heterogeneity, which is not desired, the pore size will be far less predictive.
It is measured by analytical instrument known as Porosimeter based on mercury intrusion and capillary flow methods. The volume of mercury penetrating the pores measured directly as function of applied pressure. Pore Size information is best described graphically, rather than with a single number. An alternative method of describing the distribution curve is to use a collection of values that better describe the distribution curve in more detail, i.e., upper limit, lower limit, mean, standard distribution, etc. This P-V information serves as unique characterization of pore structure. This data together with Microstructural analysis and few other test reports of the refractory sample can be of great help in optimizing the properties as well as for any failure analysis.
Types of Testing of Refractories [Read]
Apparent Porosity and True Porosity of Refractory Samples [Read]
Manipulating the Test Results of Apparent Porosity (AP) During Testing of Refractory Bricks [Read]