赤褐铁矿磁化焙烧矿物组成和物相变化规律

磁化焙烧—磁选工艺是有效处理难选弱磁性氧化铁矿的最有效方法之一,所得到的铁精矿性质与天然磁铁矿性质具有较大的差别。反浮选结果表明,人工磁铁矿和天然磁铁矿在浮选性能方面具有较大的差异,采用XRD(X-ray diffraction)、显微镜测试技术观察磁化焙烧矿物组成和物相变化,原矿中硅以碎屑石英和硅质泥岩形式存在,焙烧后有部分硅质泥岩,还有部分石英是被铁矿包裹,分布较原矿分散,即磁化焙烧形成的磁铁矿有一定的包裹、充填和浸染现象,具有不完整的晶体结构,分布分散,矿石内部组织结构的不均匀程度增加。原矿有用矿物主要以Fe2O3形式存在,脉石矿物主要是石英;焙烧后铁矿物的赋存由Fe2O3转变成Fe3O4为主,并掺杂Fe2O3,FeO,Fe,矿物组成发生变化,矿物不均匀性增强。焙烧物中还出现高铁橄榄石和铁硅酸盐峰,一部分橄榄石和硅酸盐矿物进入反浮选精矿,造成铁损失。

Regulation of Mineral Composition and Phase Transformation in Hematite and Limonite Magnetic Roasting Process

Magnetizing reduction followed by magnetic separation is one of the most effective unit operations in the treatment of refractory iron ores. Physical and chemical properties of magnetite by magnetic roasting-magnetic separation which was named artificial magnetite were different from natural magnetite. Reverse flotation results show that flotation performance has great difference between artificial magnetite and natural magnetite, X-ray diffraction and microscope testing technology were adopted to analysis flotation performance of artificial magnetite by observing change in mineral composition and phase in magnetic roasting process. Silicon of raw ore existed in the form of detrital quartz and siliceous mudstone, while silicon of roasting ore existed in the form of silica quartz, and part of the quartz was coated with iron ore, more widely spread than raw ore, incomplete crystal structure is emerged. Mineral phase composition is changed and inhomogeneity is enhanced in internal ore structure after roasting, iron mainly existed in magnetite and maghemite, peak of laihunite and iron silicate appeared in roasting ore; there were laihunite, quartz in magnetic separation concentrate of roasting ore, quartz, and in natural magnetite silicon existed in the form of quartz; part of quartz still existed in reverse flotation concentrate, part of laihunite and iron silicate entered the reverse flotation concentrate.