SiO_2-CaO-MgO-Al_2O_3熔渣中铁氧化物的分解电压

Decomposition voltage of iron oxide in SiO_2-CaO-MgO-Al_2O_3 molten slag

电解含有铁氧化物的熔融电解质提铁是一种钢铁冶炼短流程新工艺,该工艺可以减少甚至消除CO2排放。为测定熔渣中铁氧化物的分解电压,采用一端封闭的氧离子传导的氧化锆基固体电解质管内装熔渣,并以烧结在固体电解质管封闭端外侧表面的多孔铂金作为阳极,构建一种阴、阳极相互隔离的新型管状电解池。将该电解池的多孔铂金阳极置于恒定氧分压的气氛下,在熔渣中分别插入铱丝、铁棒作为阴极,利用线性扫描伏安法测定了1 723K下SiO2-CaO-MgO-Al2O3熔渣中FeO的分解电压,研究了熔渣碱度、阴极材料以及阳极气氛氧分压等因素对FeO分解电压的影响。结果表明,增大熔渣碱度、阴极还原合金化以及降低电解产物气体O2的分压,均可降低FeO的分解电压,有利于FeO的电解。测定结果与采用FactSage 6.1热力学软件理论计算的结果一致。证实采用氧离子传导的固体电解质管构建新型管状电解池,测定固体电解质管内熔渣中氧化物的分解电压是可行的。

Iron electrowinning in molten electrolyte containing iron oxide is a new technology of steelmaking process, which can reduce or eliminate the emission of CO2. In order to measure the decomposition voltage of iron oxide in molten slag, a novel tubular electrolytic cell with the isolated cathode and anode was constructed. Molten slag was contained in a one-end-closed zirconia base solid electrolyte tube with only oxygen ion conduction. Porous platinum sintered on the outside surface of the closed-end of tube was served as an anode. The porous platinum an- ode was put into an atmosphere with a constant oxygen partial pressure. An iridium wire （or iron rod）inserted into molten slag was used as a cathode. The decomposition voltage of FeO in SiO2-CaO-MgO-Al2O3 molten slag was measured by the linear sweep voltammetry at 1 723 K. The effects of some important factors such as molten slag basici- ty, cathode materials and oxygen partial pressure of the anodic gas on the decomposition voltage of FeO were investigated. The results show that the decomposition voltage of FeO in molten slag can be decreased by increasing the molten slag ba- sicity, the cathode alloying and decreasing the oxygen partial pressure of the anodic gas, which is beneficial to the electrol- ysis of FeO. The measured results were consistent with the calculations by using the FactSage 6.1 thermodynamic soft- ware. The feasibility of the novel tubular electrolytic cell constructed by one-end-closed zirconia base solid electrolyte tube for measuring the decomposition voltage of oxide in molten slag was verified.