Aluminium Sulphate (Powder) (Factory Direct Sale) Specification: Al2O3: 15.6%-17%; Fe:0.005%-1.0%; PH: 3.0min (1% water solution); Water Insolubles: 0.15%max; Size:Below 10mesh-20mesh. Aluminium Sulphate (Powder) (Factory Direct Sale) Specification: Al2O3: 15.6%-17%; Fe:0.005%-1.0%; PH: 3.0min (1% water solution); Water Insolubles: 0.15%max; Size:Below 10mesh-20mesh.