... % 1.Direct manufacturer,cheap price 2.Fe:20%min 3.FeSO4.7H2O:98%min Textile wash agent Ferrous Sulfate 99% Ferrous ... 1.Direct manufacturer,cheap price 2.Fe:20%min 3.FeSO4.7H2O:98%min 4.Insoluble matter:0.015%max Product ... to produce magnetic ferric oxide.Technical Index: ItemNational IndexEnterprise index (FeSO4 · H2O), % , ≥ 98 99 Fe,%, ≥ 19.7 20 Insoluble matter,%,≤ 0.5 ...