Recycling of coal flotation residues for the production of porous light-weight materials.

Green bodies were prepared from dewatered coal flotation tailings and from mixtures comprising 70 wt% dewatered tailings/30 wt% glass and 50 wt% dewatered tailings/30 wt% glass/20 wt% coal mining waste. Porous bricks were prepared using H2O2 as foaming agent. Optimum results were obtained for all three formulations using 3 wt% H2O2. The green bodies were fired using different temperature profiles. The products obtained could easily be cut to standard dimensions. Addition of glass reduced the total shrinkage. Firing of the 70 wt% dewatered tailings/30 wt% glass formulation at 850 degrees C produced a porous reddish brick with a bulk density of 700 kg/m3 and a porosity of more than 70 wt%.
Green bodies were prepared from dewatered coal flotation tailings and from mixtures comprising 70 wt% dewatered tailings/30 wt% glass and 50 wt% dewatered tailings/30 wt% glass/20 wt% coal mining waste. Porous bricks were prepared using H2O2 as foaming agent. Optimum results were obtained for all three formulations using 3 wt% H2O2. The green bodies were fired using different temperature profiles. The products obtained could easily be cut to standard dimensions. Addition of glass reduced the total shrinkage. Firing of the 70 wt% dewatered tailings/30 wt% glass formulation at 850 degrees C produced a porous reddish brick with a bulk density of 700 kg/m3 and a porosity of more than 70 wt%.