玻利维亚穆通铁矿石工艺矿物学研究

玻利维亚穆通铁矿石主要有价元素为铁,矿石铁品位为57.87%,99%以上的铁以磁铁矿和赤褐铁矿的形式存在。矿石中有害元素Si、Al含量稍高,主要分布在石英、硅酸盐矿物和水铝氧石等脉石矿物中。矿石构造主要有块状构造、斑状构造、浸染状构造,矿石结构主要有斑状结构、包含结构、粒状结构、残余—骸晶结构、假象结构。赤铁矿常呈不规则粒状嵌布,并以稀疏浸染状嵌布于脉石矿物中,假象赤铁矿呈斑状嵌布,斑晶中含较多脉石包裹体,局部未被完全交代的磁铁矿与假象赤铁矿共生;磁铁矿多呈自形、半自形晶粒状嵌布,常被赤铁矿交代形成残余-骸晶结构;褐铁矿主要呈斑状嵌布,与铁质黏土紧密共生。矿石铁矿物嵌布粒度粗细不均,且部分铁矿物包裹细粒石英、绢云母,即使细磨也很难使其单体解离,这就导致与铁矿物连生的脉石矿物进入铁精矿而影响精矿品位。磨矿细度为-0.074 mm占85%时,矿石中77%以上磁铁矿、赤铁矿、褐铁矿均达到单体解离,而再继续磨细时,铁矿物单体解离度随磨矿增加提高幅度不大,应选择-0.074 mm占85%的磨矿细度进行选别。

Study on the Process Mineralogy of Bolivia Mutum Iron Ore

Iron is the main valuable element of Bolivia Mutum iron ore， iron grade in the ore is 57.84%. More than 99% of the iron exists in the magnetite， hematite and limonite. The harmful impurity Si and Al in the ore is slightly higher， and it is distributed in minerals such as quartz， silicate minerals and gibbsite. Ore structure has massive structure， porphyritic structure and disseminated structure. Ore texture mainly includes porphyric structure， inclusion structure， granular structure， residual-skeletal structure， pseudomorphic structure. Hematite is usually irregularly in granular form and sparsely disseminated in gangue minerals. Martite is porphyritic and contains a lot of gangue inclusions in the phenocryst， and it is coexisted with locally untransformed magnetite. Magnetite is mostly idiomorphism and subhedral shaped grain， and it is often metasomatized by hematite to form residual-skeletal structure. Limonite is porphyritic closely intergrowth with ferric clay. The disseminated grain size of iron minerals is inhomogeneous. Part of iron minerals contain fine quartz and sericite， which are difficult to dissociate even through fine grinding. So the gangue minerals associated with iron minerals enter iron concentrate and affect concentrate grade. More than 77% of the magnetite， hematite and limonite in the ore can be liberated when the grinding fineness is -0.074 mm accounting for 85%. However， the liberation degree of iron mineral is not significantly increased when grinding fineness is increased. As a result， the grinding fineness with -0.074 mm accounting for 85% should be selected for separation.