Item Technical Requirement/ Index (Grade A) 　Technical Requirement/ Index (Qualified Product) AL2O3 % ≥15. 80 15. 80＞ Fe ≤0. 005 0. 004 Insoluble matter in water % ≤0. 3 0. 3 PH (1% solution) % 　≥3. 0 3. 0 Granularity 　mm 15 15