... factory for refractory and ceramic products best quality&cheap Calcined Alumina It adopts high quality indutrial Al2O3 as raw materials ,then ... calcined by 1400-1600 celsius degree, then crushed, into powder etc.Spec:Calcined alumina powder: Al2O3%≥99.7 Na2O%≤0 ... marble, granite,stainless steel, etc.doing ceramic products, etc. calcined alumina (refractory grade )