Porous shaped ceramic bodies prodn. - using as pore former foamed coal granulate contg. wood bark

摘要

Method of producing porous ceramic shaped bodies esp. lightweight crucibles in a raw material, esp. loam or clay in which prior to pressing a pore forming material is added, consisting of comminuted bark and/or foamed coal granulate. The bark is pref. of spruce, fir or pine-wood. The heat value of the pore forming material is 1-6 (1-4).106 kJ/m3. The pore forming material is cheap, pref. waste material. The crucibles made by this process can be fired by the normal furnace process without requiring prior burnout at below 500 degrees C at slow burnout rates due to low O2 in diffusion as in prior art, by excess burn out temp. due to excess heat of combustion of material contained. Esp. for mfr. of light weight crucibles.