refractory ceramic cooked

ceramic refractory fired product whose structure is> 90% by mass of at least one of the following groups of materials: a) ZrSiO4 b) ZrSiO4 + ZrO2 c) Al2O3d) Al2O3 + ZrO2 e) has an open porosity of 2 to 30% by volume, wherein f) more than half of the open porosity consists of pores whose diameter 1! m whose maximum diameter is 15! my these pores are in a range of pore size, the maximum value is less than or equal to 10 times the minimum value.