Preparation of porous cordierite from coal gangue and abandoned refractory materials

Porous cordierite ceramics were synthesized from coal gangue,wasted slide gates and wasted magnesia carbon bricks with graphite,starch and compound additives as pore-forming materials.The relationships between properties and synthesis conditions,such as the type and addition of pore-forming materials and heating temperature,were investigated.The result showed that high-purity porous cordierite was synthesized from coal gangue and used refractories at 1 350 to 1 400 ℃ while the compound additives was used as pore-forming materials and their addition is 15% to 25%.At the addition of the compound additives of 20%,1 350 ℃ and sintering for 3 h,porous cordierite ceramics with homogeneous pores distribution were obtained,their apparent porosity is 44.9%,thermal expansion coefficient is 2.14×10^-6 K^-1,and softening point load is 1 290 ℃.Because of these good comprehensive performances,all bricks can meet the demands of service at high temperature.