Effect of magnetic field orientation on high gradient magnetic separation performance

The magnet has a dominant role in a high gradient magnetic separator; it provides the passage for the magnetic field and the working space where the matrix is placed to produce magnetic gradients and magnetic forces high enough to capture magnetic particles from the slurry. The effect of the magnetic field orientation of the magnet on high gradient magnetic separation (HGMS) performance has been comparatively investigated on a pilot pulsating HGMS separator with vertical and horizontal magnets respectively. The results of the investigation indicate that the magnetic field orientation has a significant effect on the performance. It was concluded that a properly designed magnet in a HGMS separator greatly improves the performance.     

基于单元介质分析法的磁介质单丝捕获试验

本研究应用一种“单元介质分析法”,以钛铁矿为试样,对不同直径圆柱形磁介质进行单丝捕获试验。研究结果表明：相同磁场强度条件下,磁性矿物捕获量随磁介质丝径变小而减少;相同丝径磁介质,在任一固定的磁场强度,磁介质丝对应一个饱和捕获值;随着磁场强度的增强,不同丝径磁介质对矿粒捕获具有一定的粒级选择特征。本试验方法可以有效用于磁介质单丝捕获的准确测定,对有关磁介质单丝捕获的相关理论或模拟分析的准确性,可以进行试验验证,对磁介质在生产实践中的优化设计具有一定指导意义。     

A realistic description of influence of the magnetic field strength on high gradient magnetic separation

The magnetic field strength is a very important parameter in high gradient magnetic separation (HGMS). It was usually thought that the increase of magnetic field strength will lead to the decrease of the minerals’ susceptibility and the matrices’ surface area available for the buildup of the magnetic particles, which was responsible for the decrease of the mineral recovery in high magnetic field. But the detailed influence of the magnetic field strength on the behavior of the particles of different characteristics in HGMS is still not clear. A very important factor was usually ignored in the process of HGMS, namely the behavior of the low grade intergrowths. In this article, the influence of magnetic field strength on the behavior of the magnetic monomers and intergrowths in HGMS was investigated with the particle buildup model and the particle capture model. The buildup profile of the magnetic monomers increases with the increase of the magnetic field strength despite the decrease of the minerals’ susceptibility. The low grade intergrowths can hardly accumulate on the matrices in a low magnetic field but can largely accumulate on the matrices in a high magnetic field. In a high magnetic field, there exists the competitive accumulation between the low grade intergrowths and the fine monomers. Coarse intergrowths may have larger buildup profile and shorter capture time than the fine monomers and will accumulate preferentially on the matrices. In some circumstances, the competitive accumulation of the particles will lead to the decrease of the recovery in a high magnetic field. A moderate high magnetic field can ensure a high recovery. For a magnetic product of high grade and recovery, high monomer dissociation degree is necessary and the over grinding of the minerals should be avoided, and classifying the minerals to handle the coarse fraction and the fine fraction separately can also be considered.     

细粒嵌布硫化钼矿铜钼高效分离技术

在硫化钼矿选矿中,铜钼分离一直是矿物加工领域的难题,绿色高效黄铜矿抑制剂的研发是研究方向.本文针对中原某地细粒嵌布型极低品位硫化钼矿,基于其钼分选指标差、铜钼分离难度大等技术难题,依次开发出了辉钼矿组合捕收剂、黄铜矿绿色抑制剂以及浮选起泡剂,采用“阶段磨矿-铜钼富集-铜钼分离”工艺流程,获得了钼品位49.72％、钼回收率84.55％,铜含量0.16％的钼精矿,实验指标优异,研究成果为细粒嵌布型硫化钼矿铜钼高效分离提供了有益借鉴.     

SLon高梯度磁选机在国外某进口铁矿石的研究与应用

国外某进口铁矿TFe含量49.11%,工艺矿物学研究发现块状赤铁矿中包裹粒状磁铁矿、褐铁矿交代共生,呈脉状、网状穿插嵌布于脉石矿物中,部分赤铁矿和褐铁矿嵌布粒度过细,难以解离,影响磁选铁精矿中铁的品位和回收率。通过条件试验确定该矿物磁选条件为在弱磁选磁场强度1 000 Gs下、强磁粗选和扫选场强分别采用7 000 Gs和11 000 Gs、强磁选机脉动冲次采用210 r/min。在条件试验基础上进行了连续扩大半工业试验,弱磁选机采用SCT-44永磁磁选机、强磁选机采用SLon-500立环脉动高梯度磁选机,可获得综合精矿铁品位63.24%、铁回收率93.67%的良好指标,为国内进口铁矿采用SLon高梯度磁选机磁选回收利用提供了参考及试验依据。     

立环脉动高梯度磁选机聚磁介质优化的研究与应用

通过聚磁介质更换的工业试验,证明了优化后1.5mm和2mm混合聚磁介质,对微细粒难选赤铁矿石的分选效果更好,作业回收率提高了10%,对原矿来说提高金属回收率1.3%。尾矿中-325目粒级的损失率平均下降了5%,给公司年增加经济收入2381万元。     

高压水力冲孔半径及影响半径测试方法研究

高压水力冲孔半径和影响半径的确定直接关系着这项技术的应用设计和实施效果。为了更好地掌握高压水力冲孔范围与影响范围,增强高压水力冲孔在各煤层的适应性,通过返水法及瓦斯抽采变化获得合理的冲孔参数,优化工作面穿层高压射流冲孔钻孔的布置,进一步强化瓦斯抽采效果,需对己_15-16煤层高压水力冲孔影响半径进行测试,该研究对钻孔措施参数设计有着重要的意义。     

基于PFC 2D高梯度磁场下煤粉干式磁选行为模拟

为了清晰认识煤粉磁选行为的特性,选取矩形磁钢-锥形聚磁介质闭合磁系提供高梯度磁场环境,建立了煤粉干式磁选过程磁性颗粒动力学模型。基于二维离散元软件PFC 2D,研究了干式磁分离过程磁性颗粒运动行为,考察了磁场强度、极距、比磁化率、锥角对颗粒运动轨迹中位移、速度、平均不平衡力的影响。结果表明：磁场强度、比磁化率越大,颗粒在磁场中受力越大,位移、速度变化越明显,有益于颗粒的磁力捕集;保持颗粒距锥尖相对距离l/2,极距越小,位移、速度变化趋势越大,越有利于磁性颗粒的吸附、系统的稳定;锥角为π3时,颗粒所受磁场力最大,系统易达到平衡状态;锥角对系统影响最弱,比磁化率较极距、磁场强度对系统影响大。     

棒介质排列组合对高梯度磁选指标的影响研究

脉动高梯度磁选是微细粒弱磁性矿物的高效选矿技术,通过用微细粒赤铁矿进行脉动高梯度磁选试验,研究棒介质排列组合对高梯度磁选指标的影响。试验发现,棒介质排列组合对高梯度磁选指标具有明显影响,交叉排列优于矩形排列,可以获得更高的精矿品位、铁回收率和分选效率;随介质丝间距的增大和介质丝层数的减小,介质丝对磁性矿物的捕获能力降低,导致尾矿铁品位上升,分选效率下降,而精矿品位变化不明显。可以得出结论,棒介质排列组合优化,可以明显提升高梯度磁选的效能。     

棒介质层数对高梯度磁选指标的影响

棒介质作为高梯度磁选的一种分选介质,广泛应用于氧化铁矿、钛铁矿、黑钨矿等弱磁性金属矿的选矿和高岭土、石英、长石等非金属矿的除铁提纯。棒介质作为分选过程的载体,其结构构造(如排列、丝径、丝距、层数等)对棒介质堆内部的磁场特性和磁性矿粒动力学具有决定性影响,从而显著地影响高梯度磁选的效能。运用"单元介质"分析法,进行棒介质脉动高梯度磁选微细粒赤铁矿试验,分别研究2 mm和3 mm棒介质的介质丝层数对高梯度磁选指标的影响。试验结果表明,对每种层数的棒介质,随着磁感应强度上升,介质丝对磁性矿物的捕获能力增强,精矿产率和铁回收率增大,而精矿和尾矿品位下降,分选效率规律不明显;随棒介质层数的增加,高梯度磁选指标则明显提高。     

气流型干式磁选机在细粒磁铁矿中的应用及机理分析

目前工业界普遍采用湿式弱磁选工艺获得合格磁铁矿精矿,然而湿式工艺盛行的同时也使得缺水、寒冷等地区的同类型资源难以得到有效利用。相比于湿式,干式磁选具有环境友好、适应性强等特点,是此类资源开发利用的极佳途径。但由于细粒磁铁矿间的相互作用与磁团聚效应,干式磁选一直存在难以分散、分层、分离的技术瓶颈。针对该情况,近年来国内外科研工作者做了大量工作,基本确定了在原有设备的基础之上引入气流来实现微细粒的分散与分离的研究思路。主要围绕国内外正处于研发阶段的几类干式气流型磁选机进行论述,同时借助COMSOL有限元计算软件对各类设备的磁场、流场、粒子轨迹等机理性内容进行深入分析,综合比较各类设备的优缺点及适用范围,探究气流的最佳引入方式,以期对后续干式气流磁选机的研制和磁性矿物的干法分离提供一定的借鉴意义。     

立环脉动高梯度磁选机在梅山铁矿的应用

介绍了ＳＬＯＮ－１５００立环脉动高梯度磁选机的工业试验和应用情况,总结了该设备的优点及存在的问题。     

提高某原生钨细泥选矿指标的研究

为了充分利用矿产资源,并提高企业效益,进行了提高某原生钨细泥中黑钨矿选别指标的技术研究。经过大量的试验,最终确定采用强磁选预富集,磁选粗精矿分级进行摇床回收钨的工艺流程。原矿品位0.45%,全流程闭路试验指标为:钨精矿的产率为1.41%,WO3品位为25.50%,WO3回收率为79.90%。     

In situ observation of quartz particles entrained into magnetite coagulates in a uniform magnetic field

The entrainment of fine quartz particles into magnetite coagulates in a uniform magnetic field was studied through in situ observation using a video microscope. It is shown that the mechanisms for this entrainment are attributed to the magnetic coagulation of locked quartz-magnetite particles with free magnetite particles, the entrainment of free quartz particles into magnetite pearl chains, and wrapping of magnetite circular chains round free and locked quartz particles.     

邯邢铁矿选矿厂磁尾综合利用的设想

通过对邯邢铁矿选厂多种工艺流程的进一步分析，提出了根据矿石和流程的特点，采用不同的磁尾矿物综合利用方案，可获得较好的经济效益。     

螺旋面双入口旋风分离器流场及分离效率的数值模拟

采用非稳态RSM湍流模型对螺旋面单入口、螺旋面双入口(90°、120°、150°、180°)5种分离器的流场进行数值模拟。结果表明:螺旋面双入口分离器流场稳定且对称性好,"顶灰环"现象不明显,压力损失小,分离效率高;在相同气速条件下,随着入口旋转角的增加,分离器的压降不断变小,而且入口旋转角越大,压降随入口旋转角增大而变小的幅度越来越小;入口旋转角为90°的螺旋面双入口分离器分离效率最高。     

Interaction mechanism of miscible DDA–Kerosene and fine quartz and its effect on the reverse flotation of magnetic separation concentrate

In this study, a modification of oil assisted flotation processes of quartz particles has been proposed, which is based on introduction of miscible Dodecylamine (DDA)-Kerosene as collector with DDA cationic surfactant coated on kerosene to the hydrophilic quartz particles in the pulp. The property of miscible DDA–Kerosene emulsion was investigated. Due to the adsorption of DDA at kerosene/water interface, a smaller and uniform kerosene emulsion formed. Addition of cationic surfactant to the kerosene emulsion changed the zeta potential value from negative to positive, which resulted in enhancing the adhesion of the oil droplets to negatively charged quartz. The results showed that agglomeration and flotation process can be realized simultaneously with DDA–Kerosene. The agglomeration of fine quartz minerals in the presence of miscible DDA–Kerosene led to the formation of very large compact agglomerates resulting in increasing hydrophobicity of the particles and inducing a higher probability of collision and adhesion to air bubble. Experimental data indicated that miscible DDA–Kerosene had better selectivity and stronger collectability to quartz than DDA–HCl, which can be used as an efficient collector in the reverse flotation of magnetic separation concentrate of TISCO. At the same DDA dosage (60 g/t), separation efficiency got to 18.53% when using DDA–HCl as collector; while a better result was obtained with DDA–Kerosene, the efficiency of separation reached 59.07% which was identical with 120 g/t DDA–HCl.     

平行和垂直交叉排列组合棒介质高梯度磁选对比研究

为研究棒介质排列组合对高梯度磁选效果的影响,应用"单元介质分析法",选择铁品位38.10%的细粒赤铁矿,进行棒介质丝平行与垂直交叉排列组合对比研究。结果表明,与单一丝径棒介质比较,不同丝径组合式棒介质可以兼顾对不同粒级磁性矿粒的选择性捕获,有利于提高分选指标,且组合程度越高,提升分选指标越明显;介质丝平行与垂直交叉排列组合各有特点,后者捕获概率大些,但夹杂现象多些,因此精矿产率和铁回收率更高,但精矿品位更低。     

高梯度磁选微细粒赤铁矿尾矿的棒介质筛选

在赤铁矿、褐铁矿等弱磁性铁矿石的加工过程中会产生大量的-20μm微细粒级尾矿,目前该粒级弱磁性矿物的回收率低。对-20μm粒级65%、铁品位为28.99%的某微细粒赤铁矿尾矿,进行脉动高梯度磁选的棒介质直径筛选试验研究,了解棒介质丝径对分选指标的影响。结果表明,在磁感应强度为0.5T的条件下,1mm丝径棒介质可以获得品位为46.85%和回收率为59.39%的铁精矿,该指标明显优于当前应用的2mm和3mm棒介质。     

强化高梯度磁选分离细粒黄铜矿和辉钼矿的研究

黄铜矿和辉钼矿存在磁性差异，因此理论上两者可以采用高梯度磁选分离，并且物料粒度和粒度分布是影响高梯度磁选铜钼分离效果的重要因素。本研究分析了磁介质捕获不同细度黄铜矿的特性，开展了脉动高梯度磁选分离不同粒度黄铜矿-辉钼矿纯矿物混合矿试验，并对比研究了实际铜钼混合精矿分级后和全粒级入选的脉动高梯度磁选效果。研究表明：脉动高梯度磁选对细粒黄铜的回收效果较差，且细粒辉钼矿在磁力捕获产品中的机械夹杂明显比粗粒辉钼矿更严重。铜钼混合精矿分级后的脉动高梯度磁选铜钼分离效果，明显优于全粒级铜钼混合精矿入选的铜钼分离效果。将铜钼混合精矿分级成+0.025 mm和-0.025 mm两个粒级后，在最佳条件下开展脉动高梯度磁选试验，获得的铜精矿铜回收率为55.36%，Cu和Mo品位分别为30.86%和0.067%，钼精矿Mo回收率为91.72%。该研究结果可以用于指导脉动高梯度磁选分离铜钼的工业应用。