A New Brick Prepared from Municipal Sewage Sludge and Shale

Abstract

Series of experimental tests on the forming technique, sintering technique, performance and effectiveness of a new fired brick by mixing municipal sewage sludge and shale are carried out. Test results show that adding sludge properly in the process of manufacture shale fired common brick is feasible. Along with increase of sludge content, the compacting of uniformity of unburned brick decreased and its porosity increased. When shale-sludge mixtures were calcined, the heavy metal solidified, the ignition lost and organic substance volatilized that reduced the unconfined compressive strength (UCS) of the brick and improve its thermal insulation ability. The phase composition and leaching toxicity of sewage sludge-shale baked brick can be up to national standard. Good quality brick can be produced by blending mixture with the optimum moisture content (OMC) 18.0%-20.0%, drying at 105°C and sintering at 960°C. With all being considered in manufacturing brick, the content of sewage sludge shall be controlled within 9.0% that can make UCS of the new brick reach MU10 criterion and it has a superior heat preservation effect to normal brick from clay or shale alone.