东鞍山贫铁矿石磁选预富集行为

针对东鞍山贫铁矿石(Fe质量分数34.60%)中含有赤铁矿、磁铁矿和少量的菱铁矿，提出了一种弱磁粗选-高梯度扫选的预富集工艺，并借助XRD、铁的化学物相分析及扫描电镜(SEM)考察了磁场强度和原料磨矿细度对东鞍山铁矿石预富集行为的影响.结果表明，在磨矿细度-0.074mm占70%(质量分数)、弱磁粗选磁场强度120mT、高梯度扫选Ⅰ磁场强度300mT及高梯度扫选Ⅱ磁场强度800mT的条件下，可获得Fe质量分数42.67%、回收率95.45%的预富集精矿;磁铁矿富集于弱磁粗选作业中，赤铁矿和菱铁矿在高梯度扫选作业中得到有效富集，尾矿中丢失的铁矿物主要为微细粒赤铁矿(＜10μm)，由于受到的磁性捕获力弱而无法得到回收.

Pre-enrichment Behaviors of Low-Grade Donganshan Iron Ore Using Magnetic Separation

A pre-enrichment process of low-intensity magnetic roughing followed by high-gradient magnetic scavenging was proposed， and the effects of magnetic field intensity and grinding fineness on pre-enrichment behaviors of low-grade(w(TFe)=34.60%) Donganshan iron ore simultaneously containing hematite， magnetite and a bit of siderite were studied by XRD， chemical phase analysis of iron， and scanning electron microscope(SEM). The results showed that the optimized grinding fineness of raw ore was 70% passing 0.074mm， the magnetic field intensity for roughing， scavenging Ⅰ and Ⅱ were 120mT， 300mT and 800mT， respectively. Under the optimized conditions， a magnetic pre-concentrate assaying 42.67% iron (mass fraction) with an iron recovery of 95.45% was achieved. The analyses revealed that ferromagnetic magnetite was enriched in low-intensity magnetic concentrate， and weakly magnetic hematite and siderite were recovered successfully by high-gradient magnetic separation. However， some ultra-fine hematite particles(＜10μm) were lost in tailing due to their weak magnetic trapping force.