... in an electric arc furnace. White electro corundum is iron-free, ultra pure and extremely hard.White electro corundum for Abrasive and ... /cm33.50minMohs hardness---9.00minPrincipal crystalline phase---α-Al2O3Refractory gradeGrainmm0-50,0-1, 1-3, 3-5,5-8Finesmesh-200 ... /cm33.50minMohs hardness---9.00minPrincipal crystalline phase---α-Al2O3Refractory gradeGrainmm0-50,0-1, 1-3, 3-5,5-8Finesmesh-200 ...