梅山自产铁矿石矿物工艺学研究

为更好地开发利用梅山铁矿石资源,开展了工艺矿物学研究。结果表明:①半自熔性混合铁矿石中有回收价值的铁矿物磁铁矿、赤褐铁矿、假象赤铁矿中的铁总分布率达73.97%;磁铁矿多为粒状、不规则粒状、多孔不规则状,粒度悬殊,一般在0.03~0.6 mm,粗粒中常包裹有不等量的细小脉石颗粒,磁铁矿普遍发生了氧化蚀变,生成假象赤铁矿及赤铁矿,因而磁铁矿与赤铁矿共生关系紧密;假象赤铁矿部分与磁铁矿紧密交生产出,部分形成独立的矿粒,粒度一般在0.02~0.3 mm;赤铁矿多为不规则粒状、多孔状,粒度一般在0.015~0.4 mm,只有少部分赤铁矿呈单独矿物出现,与脉石矿物的嵌布关系较磁铁矿紧密。②不同种类的脉石矿物常构成脉石集合体,部分嵌布在不同种类铁矿物间隙,方解石、白云石结晶粒度较粗,与菱铁矿嵌布密切;石英晶粒较细小,部分聚集为集合体,分布较为分散,在脉石矿物及铁矿物间隙中均有嵌布;长石、云母等硅酸盐矿物分布较分散,多与细小石英混杂呈岩屑嵌布在不同矿物间。③在碎至-2 mm样品中,磁(赤)铁矿、菱铁矿单体较少,磁(赤)铁矿单体加富连生体合计占68.55%,这为在较粗粒度下进行预富集创造了条件,有利于减少后续磨选矿量,提高后续磨选给矿品位,减少细粒尾矿量,达到良好的节能减排、降本增效效果。

Mechanism of improved magnetizing roasting of siderite–hematite iron ore using a synergistic CO–H2 mixture

A fluidized-bed magnetizing roasting-magnetic separation process was selected to treat this type of material.Phase transformations and microstructural changes in the product resulting from magnetizing roasting under different reducing gases(CO,H2,CO+H2)were clarified by vibrating sample magnetometry,X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray spectroscopy.The results indicated that the conversion ratio and saturation magnetization of samples roasted in a mixed gas of CO and H2 were higher than those of samples produced under CO or H2 alone.This indicated that synergy of the combined CO and H2 gas had a positive effect on the fluidized-bed magnetizing roasting process.The mechanism and kinetics of the improved magnetizing roasting of a siderite-hematite iron ore mixture under this synergistic CO-H2 system were investigated under isothermal conditions.The results indicated that the apparent activation energies of the reactions of the iron oxides decreased from 37.7 and 17.9 to 15.9 kJ/moI when the roasting atmosphere was changed from pure H2 or CO to a gas mixture of CO and H2,respectively.The mixed CO-H2 gas promoted the conversion ratio of hematite and siderite to magnetite,thereby improving the conversion ratio in the fluidized-bed magnetizing roasting process.

某微细粒复合菱-磁铁矿石综合回收研究

针对某铁矿石矿物组成复杂、菱铁矿和磁铁矿共生密切,且磁铁矿嵌布粒度细、分布分散,有害元素硫含量较高等复杂条件。在探索试验的基础上,最终确定阶段磨矿、原矿磁选预富集-细磨反浮选脱硫-磁选-焙烧-磁选的工艺流程,产出以磁性铁为主的高品位铁精矿和以菱铁矿焙烧产物为主的低品位铁精矿。全流程试验获得高品位铁精矿铁品位62.56%、回收率26.38%,中品位铁精矿铁品位55.54%、回收率48.12%的指标。