镜铁矿悬浮磁化焙烧过程中的铁物相与磁性转变研究

Study on Iron Phase Transformation and Magnetic Transformation during Suspension Magnetization Roasting of Specularite

甘肃某镜铁矿石主要有价元素为铁,TFe含量为59.61%,原矿中94.79%的铁以赤褐铁的形式存在,脉石矿物主要为石英,含量为8.11%。为考察焙烧过程主要影响因素对焙烧产物的物相转化与磁性转变的影响,进行了悬浮焙烧试验。结果表明:镜铁矿经悬浮磁化焙烧后,焙烧产物中铁主要以磁铁矿的形式存在,磁性明显增强;随着焙烧温度升高、焙烧时间延长、CO浓度增加、总气量增加,焙烧产品中镜铁矿含量均逐渐降低,磁铁矿含量均逐渐增加,焙烧产品饱和磁化强度和最大比磁化系数均先提高后降低;在焙烧温度为550℃、焙烧时间为4 min、CO浓度为20%、总气量为600 mL/min时,焙烧产物的比饱和磁化强度为63.66 A·m2/kg、最大比磁化系数为5.02×10-4m3/kg;焙烧过程铁物相按照Fe2O3→Fe3O4→FeO的反应顺序进行,焙烧产物铁物相的转化会影响铁矿物磁性的强弱,并且主要与磁铁矿的含量相关。试验结果可以为我国镜铁矿资源悬浮焙烧过程机理研究提供理论依据。

The main valuable element of a specularite ore in Gansu Province is iron. The content of TFe is 59.61%.94.79% of the iron in the raw ore exists in the form of hematite and limonite. The gangue mineral is mainly quartz and the con?tent is 8.11%. In order to investigate the effect of main factors on phase transformation and magnetic transformation of roasted products,suspension roasting experiments were carried out. The results show that after the suspension magnetization roasting of specularite,the roasted product iron mainly exists in the form of magnetite,and the magnetism is obviously enhanced.With the increase of roasting temperature,roasting time,CO concentration and total gas volume,the content of specularite in roasted products decreases gradually,the content of magnetite increases gradually,and the saturation magnetization and max?imum specific magnetization coefficient of roasted products increase first and then decrease. The specific saturation magnetiza?tion of the roasted product is 63.66 A·m2/kg and the maximum specific magnetization coefficient is 5.02×10-4 m3/kg when the roasting temperature is 550 ℃ and the roasting time is 4 min,the concentration of CO is 20% and the total gas volume is 600 mL/min. The iron phase in the roasting process changes in the order of Fe2 O3→Fe3 O4→FeO. The transformation of the phase of the roasted product will affect the magnetic strength,and is mainly related to the content of magnetite. The experimental re?sults can provide theoretical basis for the mechanism of suspension roasting of specularite resources in China.