尾矿酸浸液除硅以及制备高纯铁红的研究

金川公司尾矿酸浸液中除含有较高含量的铁之外，还含有一定量的杂质硅。以氧化钙为中和剂，聚丙烯酰胺为絮凝剂，通过正交设计与实验，得出了从该酸浸液中除硅的较佳工艺条件；随后，以氧化镁为中和剂，空气和双氧水为氧化剂，将除硅后滤液在85 ℃搅拌加热，制得针铁矿沉淀；最后将沉淀在800 ℃煅烧2 h并经过5%稀硝酸洗涤得到了高纯铁红，其主成分质量分数为99.2％，符合HG/T 2574-2009工业氧化铁国家标准。

Study on removal of silicon and preparation of high purity ferric oxide red from acid leaching filtrate of tailings

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.