中文摘要：

在高压水热反应釜内，以纤维素为还原剂将黄钾铁矾渣中的Fe（Ⅲ）还原为可磁选分离的磁铁矿（Fe3O4）。系统考察了水热温度及还原时间等对Fe（Ⅲ）还原的影响，并借助XRD及SEM等分析了不同还原条件下还原产物的微观形貌和物相构成。结果表明，在260℃还原6h的条件下，Fe（Ⅲ）的还原率可达到51．8％。反应产物经磁选后可获得磁铁矿精矿。

英文摘要：

Fe（Ⅲ） in jarosite slag was reduced and magnetically separated as magnetite （Fe3O4） in high pressure hydrothermal reactor with cellulose as reductant. Effects of hydrothermal temperature and reduction time on reduction of Fe （Ⅲ） were investigated. Microstructure and phase composition of reduction products were analyzed by XRD and SEM. The results show that reduction rate of Fe（Ⅲ） is 51.8% under the conditions of temperature 260 ℃ and reaction time of 6 h. Magnetite concentrates can be obtained from reaction products by magnetic separation.