Heat treating refractory bricks contg. tar - to remove volatile constituents in tar content by heating in oxygen free inert gas

摘要

The refractory materials are bonded or impregnated with tar, and are esp. bricks made of dolomite and/or magnesite or chamotte. Treatment consists of heating the bricks in an inert gas (a) free from O2; and then cooling the bricks in inert gas (b) free from tar constituents until the bricks are below the ignition temp. of the carbon remaining in the bricks. In the pref. process and plant, a tunnel kiln is used, and gases (a,b) are obtd. by burning gas or liq. fuels; and the volatile constituents in the tar are burned in the inert gas with the aid of heat and O2 so that new inert gas free from O2 is obtd. The kiln has an air lock followed by tempering and cooling zones fed with inert gas, then an air cooling zone. The bricks are heated to >=700 degrees C so they are suitable for use without causing environmental pollution; and without explosions in the heat treatment plant. The bricks are used to make converter linings.