Abstract: Acid leaching filtrate of tailings from Jinchuan Company contains not only large amount of Fe²⁺ but also small amount of Si⁴⁺.Using CaO as neutralizer and polyacrylamide as flocculation reagent，the optimum technological conditions of removal of silicon from the acid leaching filtrate were obtained by orthogonal experiments.After silicon was removed，goethite was prepared under the conditions of 85 ℃ and stirring by using MgO as neutralizer and air together with H₂O₂ as oxidant.Finally the high purity ferric oxide red（α-Fe₂O₃） was prepared by calcining goethite at calcining temperature of 800 ℃ for 2 h followed by washing with 5% dilute HNO₃. The mass fraction of main content of the as-prepared iron red was 99.2%，which could be classified as the qualified product according to the national standard of HG/T 2574—2009.

Key words: acid leaching filtrate of tailings, flocculation, removal of silicon, ferric oxide red