Process for making macro porous ceramic spheres

Process for making macro porous ceramic spheres with or without a central cavity having cross/inter linked web of macro porous zigzag conduits embedded in the sphere comprising

• dry pulverizing a composition comprising talc, calcined talc, china day, calcined clay and calcined alumina homogenized with <20% combustible particles to form filler-binder;
• uniformly sprinkling said homogenized mass in a pan pelletizer separately wetted with cold water mixed <2% PVA aqua sol binder while being continuously rolled there within to forming green spheres with <25% moisture and burnable core particles;
• dry roll compacting said green spheres before oven drying at 90-110 deg. C. until moisture and burnable core particles are partially removed therefrom before being sintered in a rotary kiln at temperature between 1350 and 1380 deg. C. for 45-60 minute kiln time duration, giving a rotary motion to the spheres which enables uniform thermal treatment in air atmosphere allowing said sintered spheres cool down rapidly to ambient temperature before sieving, and
• recovering therefrom >90% ceramic spheres with <5% volume shrinkage and <2% cracked/broken spheres ideal for uses as low-to-high temperature loose fill catalyst carriers for mobile or stationary application or for being moulded into bricks/monoliths forming high temperature refractory applications having product characteristics comprising indialite as the XRD major phase and an average crush strength of 11 to 32 pounds.