菱铁矿作为我国复杂难选铁矿石的代表之一,资源储量巨大.实现菱铁矿资源的有效开发利用,对我国钢铁工业的可持续发展具有重要的战略意义.在对菱铁矿开展悬浮磁化焙烧试验及冷却氧化试验基础上,通过X射线衍射分析(XRD)及振动样品磁强计(VSM)等手段重点研究了冷却氧化过程中的物相转化和磁性转变规律.结果表明:氧化温度和氧化时间对氧化过程有显著的影响,O2 浓度的影响较小.随着氧化温度的升高,焙烧产物的氧化程度不断加深,氧化产物饱和单位质量磁矩不断减小.在氧化温度为 200℃至 400℃时氧化反应剧烈,不断生成γ-Fe2O3 和α-Fe2O3.焙烧产物氧化过程中,磁铁矿主要以Fe3O4→γ-Fe2O3→α-Fe2O3 顺序发生氧化,氧化产物磁性不断减弱,氧化反应基本完成的时间为 6 min.
Study on Cooling Oxidation Process of Siderite by Magnetization Roasting
As one of the representatives of complex refractory iron ore in China,siderite possessed huge resource re-serves.The effective development and utilization of siderite resources were of great strategic significance to the sustainable de-velopment of China's iron and steel industry.Based on the experiments of suspension magnetization roasting and cooling oxida-tion of siderite,the phase transformation and magnetic transformation during cooling oxidation were studied by means of X-ray diffraction(XRD)and vibrating sample magnetometer(VSM).The results revealed that the oxidation temperature and time had a significant effect on the oxidation process,whereas the effect of O2 concentration was minimal.As the oxidation tempera-ture increased,the oxidation degree of the roasting products deepened,and the saturated magnetic moment per unit mass of the oxidation products decreased.At 200 ℃ to 400℃,the oxidation reaction was intense,with γ-Fe2O3 and α-Fe2O3 being contin-uously generated.During the oxidation process of the roasting products,magnetite was primarily oxidized in the sequence of Fe3O4 → γ-Fe2O3 → α-Fe2O3,and the magnetic properties of the oxidation products continued to weaken.The oxidation reac-tion was essentially completed when the oxidation time reached 6 min.
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