甘肃某微细粒极难选铁矿石工艺矿物学研究

Process Mineralogy Study of a Fine-grained Extremely Refractory Iron Ore in Gansu

为开发利用甘肃某微细粒极难选铁矿石,采用化学成分分析、铁物相分析、能谱分析、光学显微镜、扫描电镜等方法对其进行工艺矿物学研究。结果表明,矿石TFe品位为32.70%,铁主要以磁铁矿形式存在,其次为褐铁矿和菱铁矿,有害元素S、P含量分别为0.21%和0.28%;脉石矿物主要为角闪石和石英,少量黏土矿物、磷灰石。矿石主要构造为块状构造和层状构造,主要结构为浸染状结构、粒状结构、针状结构、纤维状结构及斑状结构等。矿石中磁铁矿主要呈自形、半自形细粒浸染状嵌布于脉石矿物中,褐铁矿主要呈针状、纤维状及不规则细粒状与脉石矿物共生嵌布,菱铁矿主要呈不规则粒状集合体与石英、磁铁矿共生嵌布;3种铁矿物嵌布粒度极细,-0.040 mm粒级分布率分别为94.23%、85.06%、66.79%,-0.015 mm粒级分布率分别为64.53%、57.56%、31.50%,很难完全解离。矿石在磨至-0.022 mm占90%时,磁铁矿、褐铁矿、菱铁矿的单体解离度分别为67.92%、70.88%、84.16%,欲使铁矿物充分解离需进一步细磨。依据工艺矿物学研究结果,推荐矿石采用“原矿阶段磨矿—弱磁选—强磁选—反浮选”的选矿工艺。

In order to develop and utilize a certain fine-grained and extremely difficult-to-separate iron ore in Gansu,chemical composition analysis,iron phase analysis,energy spectrum analysis,optical microscope,scanning electron microscope and other methods were used to study its process mineralogy.The results show that the TFe grade of the ore is 32.70%,the iron mainly exists in the form of magnetite,followed by limonite and siderite,the content of harmful elements S and P are 0.21%and 0.28%respectively;the gangue minerals are mainly horn flash stone and quartz,small amounts of clay minerals,apatite.The main structures of the ore are massive structure and layered structure,and the main structures are disseminated structure,granular structure,needle-like structure,fibrous structure and spot-like structure.In the ore,magnetite is mainly euhedral and semi-hedral fine-grained disseminated inlaid in gangue minerals,limonite is mainly in needle-like,fibrous and irregular finegrained shapes and intergrown with gangue minerals,siderite.The ore is mainly in the form of irregular granular aggregates,symbiotically embedded with quartz and magnetite;the three iron minerals are embedded with extremely fine particle size,and the particle size distribution rates of-0.040 mm are 94.23%,85.06%,66.79%,and-0.015 mm respectively.The particle size distribution rates were 64.53%,57.56%,and 31.50%,respectively,and it was difficult to dissociate completely.When the ore is ground to-0.022 mm and accounts for 90%,the monomer dissociation degrees of magnetite,limonite,and siderite are 67.92%,70.88%,and 84.16%,respectively.To fully dissociate iron minerals,it is necessary to further dissociate finely ground.According to the research results of process mineralogy,it is recommended to adopt the beneficiation process of"raw ore stage grinding-low intensity magnetic separation-high intensity magnetic separation-reverse flotation".