a white roll or spherical particle,insoluble in water and organic solvent,soluble in acidic and alkaline solutions,moisture absorptive in air,not expanding and cracking after adsorbing water,with the characters of high strength and good thermal stability. speicfication: roll diameter 3*3--8mm sphere diameter 2--3mm used as catalyst carrier for hydrogenation and de-sulfuration in petrochemical industry and chemical fertilizer production. Al2O3:more than 92% Bulk density:less than 0.80g/ml BET:170--230m2/g Porosity Volume:more than 0.35ml/g