Removal of phosphate from municipal sewage by high gradient magnetic separation

The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, magnetic field intensity, pH value and flow-rate of sewage on phosphorus removal rate were investigated. The results show that addition of 200 mg/L Al2（SO4）3·18H2O and 300 mg/L Fe3O4, magnetic field intensity of 200 kA/m, pH value of 4.57.0 and flow-rate of 6.15 cm/s are both efficient and economic technical parameters for removal of phosphate. The pH value has a tremendous effect on the removal of phosphate. In the pH range of （4.5）7.0, more than 95% phosphate can be removed. Theoretical analysis indicates that the solubility of AlPO4 is minimum at pH 4.07.0 and the electrostatic attractive force between AlPO4 and Fe3O4 is maximum at pH 4.5（6.5.）

KAOLIN CLAY PURIFICATION BY DRY HIGH GRADIENT MAGNETIC SEPARATION

A new method-dry High Gradient Magnetic Separation （HGMS）-to remove iron from ultrafine kaolin powder is described. A new kind of disperser, which breaks down the particle clusters in the powder by high speed gas flow from an air compressor, is used to completely disperse the powders. The dispersed particles are passed through vibrating HGMS by a vacuum pump to remove the iron. The magnetic and nonmagnetic fractions are separately collected by cloth collectors. Dry HGMS laboratory experiments are carried out. A product containing 0.90％ Fe2O3 was obtained, and the recovery was 70％.

Study on Optimizing High-Gradient Magnetic Separation—Part 2: Experimental Evaluation of the Performance of a New Designed Magnetic Filter

The introduction of functionalized magnetizable particles and high-gradient magnetic separation represents a time and money saving alternative to conventional purification and separation unit operations in the biotechnical sector. This technique has some advantages especially for the recycling of immobilized enzymes. A new magnetic filter with sight glasses was constructed and produced to study the performance of high-gradient magnetic separation at varied parameters. By optical analysis the buildup of a clogging was identified as the major parameter which affected the separation performance. For the cleaning procedure, a two-phase flow of water with highly dispersed air bubbles was tested which led to a nearly complete cleaning of the filter chamber.

Study on Optimizing High-Gradient Magnetic Separation—Part 1: Improvement of Magnetic Particle Retention Based on CFD Simulations

The introduction of functionalized magnetizable particles for the purification of enzymes or for the multi-use of pre-immobilized biocatalysts offers a great potential for time and cost savings in biotechnological process design. The selective separation of the magnetizable particles is performed for example by a high-gradient magnetic separator. In this study FEM and CFD simulations of the magnetic field and the fluid flow field within a filter chamber of a magnetic separator were carried out, to find an optimal separator design. The motion of virtual magnetizable particles was calculated with a one-way coupled Lagrangian approach in order to test many geometric and parametric variations in reduced time. It was found that a flow homogenisator smoothed the fluid flow, so that the linear velocity became nearly equal over the cross section in the direction of flow. Furthermore the retention of magnetizable particles increases with a high total edge length within the filter matrix.

Innovative pre-concentration technology for recovering ultrafine ilmenite using superconducting high gradient magnetic separator

To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was proposed in this study.After optimizing the conditions of magnetic intensity,feeding and pulsation,an SMS concentrate with TiO_(2) grade of 16.03% and TiO_(2) recovery of 66.39% was obtained through one roughing-one cleaning pre-concentration flowsheet.The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism,and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective preconcentration of the ultrafine ilmenite in the SMS process.In addition,the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology.Furthermore,the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology.

MAGNETIC SEPARATION OF FLUID CATALYTIC CRACKING EQUILIBRIUM CATALYST

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高梯度磁选中非磁性颗粒的机械夹杂行为

非磁性矿物颗粒的机械夹杂是影响高梯度磁选选择性的重要因素。基于自主设计的高梯度磁选试验装置,对磁介质上、下游累积物进行冷冻、剥离和独立分析,系统研究了各种关键参数对非磁性颗粒机械夹杂行为的影响。结果表明,磁介质下游捕集的选择性都优于上游。非磁性矿物的机械夹杂主要发生在介质上游,增加给矿流速和减小非磁性颗粒的粒度可以提高高梯度磁选的选择性,磁场强度对介质上下游机械夹杂的影响较小。在较低流速条件下,弱化上游捕集和强化下游捕集具有重要意义,并提出了提高选择性的两种潜在技术方案。

A study on the rare earth ore containing scandium by high gradient magnetic separation

Scandium (Sc) concentration from the rare earth ore by high gradient magnetic separation (HGMS) was determined on the basis of Sc content, geophysical parameter determination and the magnetic analyses of the ore. Based on the condition experiments, expanding experiments were carried out. The results showed that the ore had a Sc grade of 48.90 g/t, and after removing iron by low-intensity magnetic separation, a Sc concentrate of 314.89 g/t grade and with 77.53% recovery was obtained by one-stage roughing-one...

脉动高梯度磁选分离微细铜钼混合精矿试验研究

黄铜矿(顺磁性)和辉钼矿(逆磁性)存在微弱的磁性差异,可以通过高梯度磁选分离。采用SLon-100型周期式脉动高梯度磁选机,对金堆城钼业某铜钼混合浮选粗精矿(铜、钼品位分别为14.42%和12.40%、-0.019 mm产率83.80%)进行了黄铜矿与辉钼矿分离试验研究。结果表明,在脉动冲程为5 mm、脉动冲次为150 r/min、棒介质直径为1.5 mm、矿浆流速为2.0 cm/s、粗选磁感应强度为1.6 T、扫选磁感应强度为1.7 T的条件下,经1粗1扫脉动高梯度强磁选,获得了产率48.64%、铜品位22.82%、钼品位4.40%和铜回收率77.82%的铜精矿,及产率51.36%、铜品位6.16%、钼品位19.96%和钼回收率82.73%的钼精矿,实现了有效的微细粒铜钼矿物分离。研究结果证明了脉动高梯度磁选分离微细粒铜钼混合精矿的有效性,可以为类似铜钼混合精矿的绿色分离提供指导。

黔北某菱锰矿高梯度脉冲磁选及影响因素研究

对贵州北部某典型低品位菱锰矿进行了工艺矿物学分析,结果表明,矿石中锰品位为12.82%,Mn/Fe3.93,P/Mn0.02,S/Mn0.15,Mg/Ca0.32,矿石属于高铁高磷高硫高硅高黏土菱锰矿。菱锰矿多呈泥晶集合体结构,矿石中Mn89.47%赋存于钙菱锰矿中,Mn与Ca类质同象严重,菱锰矿属于不均匀粒度分布。采用“一粗(1.2T)一扫(1.3T)”高梯度脉冲磁选流程,得到回收率85.01%、品位为18.19%的磁选精矿指标。经AMICS产品特征研究结果表明,精矿品位及回收率难以提高的主要原因是菱锰矿中Mn被Ca类质同象,该特征造成菱锰矿无法实现单体解离,使菱锰矿中钙质随磁选进入精矿,方解石及白云石中锰质难以回收,降低精矿品位及回收率。其次该矿石嵌布粒度不均匀,部分白云石及微晶黄铁矿在钙菱锰矿中分布,造成菱锰矿与脉石矿物形成连生体,难以实现磁选分离,恶化精矿指标;最后是菱锰矿精矿锰品位的提升需增加磨矿细度实现单体解离,而矿石中存在大量黏土矿物、颗粒过细加重泥化、团聚现象,造成细粒菱锰矿颗粒与脉石矿物形成异质团聚体,当团聚体的体积比磁化率达到磁选回收界限时,团聚体中脉石矿物也被带入精矿降低质量,当团聚体的体积磁化率未能达到磁选回收界限时,团聚体中菱锰矿随脉石矿物被水流带走,造成跑尾降低精矿回收率。

基于煤矸石中锂、镓元素赋存状态的高梯度磁选预富集试验

我国山西、内蒙古部分矿区煤矸石中蕴藏着锂、镓等战略性关键金属,其锂、镓元素富集逐渐成为研究热点。然而煤矸石中锂、镓含量很低,直接浸出需消耗大量化学药剂,高效、经济的富集锂、镓元素仍存在很大挑战。为提高煤矸石中锂、镓富集效率,针对山西朔州地区煤矸石中锂、镓元素赋存状态和预富集方法展开研究。采用逐级化学提取法、矿物物相组成、矿物解离分析、电感耦合等离子体质谱法、扫描电子显微镜和能量色散光谱,研究了煤矸石中锂、镓元素的赋存状态,利用高梯度磁选探究通过抛除黄铁矿对煤矸石中锂、镓元素预富集的可行性。结果表明,煤矸石主要由高岭土、黄铁矿、石英、方解石、白云母等矿物组成,锂、镓元素主要赋存于硅酸盐类矿物中,黄铁矿中含量较少。原矿中锂质量分数146.37μg/g,镓质量分数25.04μg/g。通过磁选方法抛除黄铁矿可对煤矸石中锂、镓元素预富集,1000 mT时,预富集效果最佳,磁选尾矿中锂质量分数210.63μg/g,为原矿中锂含量的1.45倍,锂回收率88.00%。镓质量分数31.88μg/g,高于原矿中镓元素,镓回收率80.07%。

攀西橄辉岩型低品位钛铁矿振动脉动与脉动高梯度磁选工艺对比

随开采深度的增加,攀西钛铁矿中易泥化、与钛铁矿磁性差异较小的橄辉岩型钛铁矿含量增多,降低了脉动高梯度磁选机的分选指标,使后续浮选过程中合格钛精矿的生产成本和难度增大。针对这一问题,本文开展振动脉动高梯度磁选与脉动高梯度磁选橄辉岩型低品位钛铁矿的对比试验研究。结果表明:在钛粗精矿的TiO_(2)品位为9.00%、−0.074 mm粒级产率为57.60%的条件下,采用SLon−100周期式脉动高梯度磁选机分选时,所得磁性精矿的TiO_(2)品位为15%~17%,分选精度上限较低;采用SLon-Z−100周期式振动脉动高梯度磁选机分选时,所得磁性精矿的TiO_(2)品位为20%~22%,分选精度上限明显提高。在相近的磁性精矿TiO_(2)品位(15%)或TiO_(2)回收率(73%)条件下,振动脉动高梯度磁选工艺的各项分选指标均明显优于脉动高梯度磁选工艺,表明磁介质振动动态捕获模式具有更高的捕获选择性。

缅甸某低品位复杂难选铁锡矿石综合回收试验研究

缅甸某低品位铁锡矿石含铁29.79%、锡0.495%,脉石成分主要为Si O_(2),主要有价矿物为磁铁矿和锡石,二者紧密共生,粒度较细。为确定该矿石的高效开发利用工艺,基于原矿性质研究,采用湿式弱磁选铁—锡石回收(摇床重选—摇床中矿再磨后高梯度强磁选除铁—摇床重选)—锡综合粗精矿浮选脱硫磁选除铁(弱磁选+高梯度强磁选)流程进行了选矿试验。结果表明:该工艺最终可获得锡品位57.956%、锡回收率69.08%的锡精矿,铁品位65.21%、铁回收率48.22%的铁精矿,硫品位46.35%、硫回收率38.31%的硫精矿,铁、锡和硫精矿所含杂质均未超标,总尾矿的锡品位降至0.153%,实现了铁锡矿石资源的综合回收利用。

高梯度磁选理论与技术进展

在高梯度磁选分离过程中存在机械夹带、磁性夹带、竞争捕获等现象,最终导致选择性差、分选腔堵塞、分选效率低等一系列问题。目前科研工作者针对高梯度磁选的理论研究主要集中于对颗粒受力分析并力的大小计算、颗粒轨迹模型和颗粒堆积模型的构建、聚磁介质的研发与优化。以颗粒受力为基础,通过颗粒的堆积模型和轨迹模型分析造成选择性差以及效率低的原因,综述聚磁介质的研发与优化,旨在为高梯度磁选技术在工业应用中的优化与理论研究提供参考,并对高梯度磁选技术理论研究的未来趋势进行展望。

某氰化尾渣中磁选回收铁试验研究

为综合回收利用某含金银多金属氧化矿氰化尾渣中的铁,针对氰化尾渣进行了弱磁选和强磁选回收铁的试验研究。试验结果表明:在弱磁粗选磁场强度为238.85 kA/m,弱磁精选磁场强度为159.24 kA/m,弱磁粗选尾矿强磁选磁感应强度为1200 mT的条件下,通过弱磁—强磁分选工艺,获得了全铁品位为64.08%、铁回收率为21.11%的弱磁铁精矿和全铁品位为45.81%、铁回收率为40.31%的强磁铁精矿,综合全铁回收率为61.42%,达到了综合回收利用铁资源的目的。

基于转子极性判断优化的脉振高频电压注入法

在永磁同步电机零速和低速运行时,采用脉振高频注入法能够准确估计转子位置信息。针对脉振高频注入法无法实现转子极性判断,而传统极性判断方法存在响应时间长、采样和实施过程复杂以及极性误判等问题。文中提出了一种基于正负电压脉冲注入的电机转子极性判断方法。该方法给电机注入正负电压脉冲,并根据对应脉冲的响应电流峰值判断转子极性。脉振高频注入法将转子位置估计值和极性判断结果相结合,可得到准确的转子初始位置。文中通过Simulink仿真验证算法的有效性。仿真结果表明,所提转子极性判断方法能够简化采样方式和算法复杂性,降低判断转子极性的响应时间,使脉振高频注入法能够准确和快速地估计转子初始位置。

湖北鄂东某陶瓷用长石除铁增白选矿试验研究

为合理高效开发湖北鄂东某陶瓷用长石矿资源,基于原矿工艺矿物学分析,进行除铁增白试验研究。结果表明,原矿中主要有用矿物为斜长石和钾长石,脉石矿物为石英、石榴子石、云母、磁铁矿、褐铁矿及少量的赤铁矿,其中含铁杂质是影响白度的主要因素。采用“水洗脱泥-磁选脱铁”联合流程,可以获得产率为97.16%的长石精矿,其铁杂质含量从1.105%降至0.295%,白度相应由46.11%提升至64.92%,同时Na_(2)O与K2O总量略有提升,精矿产品各项指标达到QB/T 1636-2017《日用陶瓷用长石》行业标准钠长石合格品的要求,实现了该长石矿的高附加值利用。

某锂云母粗精矿磁选再富集试验研究

江西某锂云母经浮选后粗精矿锂品位2.60%左右,产品竞争力较弱。为提高该锂云母精矿的市场竞争力,达到锂品位3.0%以上的要求,进行锂云母粗精矿磁选再富集试验。研究结果表明:在磨矿细度-0.074 mm65%、给矿浓度25%、磁介质棒直径3 mm、强磁粗选1背景磁感应强度1.3T、强磁粗选2背景磁感应强度1.5 T的条件下,采用2次强磁粗选工艺流程,可获得锂品位3.03%、锂回收率82.03%的锂云母强磁选精矿;试验达到了对现场浮选精矿再富集的效果,可作为现场工艺改造的依据。

某钽铌锡混合精矿磁选分离试验研究

采用高梯度磁选机分选某重选钽铌锡混合粗精矿,研究了磁场强度、脉动冲次、磁介质及转环转速对该精矿中钽铌和锡分离效果的影响。结果表明,在给矿钽品位11.65%、铌品位9.33%、锡品位19.59%条件下,最终可获得含钽22.31%、含铌17.38%、含锡3.22%、钽回收率95.48%、铌回收率92.88%、锡回收率8.20%的钽铌精矿,同时可获得锡品位35.87%、锡回收率91.80%的锡精矿,钽铌和锡得到有效分离。

四川某低品位弱磁性铁矿脉动高梯度磁选试验研究

四川某铁矿石原矿铁品位较低为25.40%,硅酸铁分布率达55.04%,可利用的铁矿物以赤铁矿、褐铁矿等弱磁性矿物为主,理论回收率为44.06%。由于铁矿物嵌布粒度细,回收利用难度大,综合考虑经济成本和技术可行性,拟定了“磨矿—脉动高梯度磁选粗选—粗精矿再磨—脉动高梯度磁选精选”的技术路线分选该矿石。通过脉动高梯度磁选粗选条件试验着重考察了磨矿细度、磁感应强度、脉动频率和矿浆流速对粗选结果的影响,确定了最佳粗选条件为:原矿磨矿细度-0.074mm粒级占80%、磁感应强度0.6T、脉动频率250r/min、矿浆流速6cm/s,在此条件下粗选可获得铁品位34.97%、回收率67.74%的粗精矿;为进一步提高粗精矿铁品位,对粗精矿再磨后进行精选,在粗精矿再磨细度-0.038mm粒级占97.16%、磁感应强度0.4T、脉动频率350r/min、矿浆流速8cm/s的条件下,可获得铁品位41.08%、回收率37.40%的精矿产品。在上述最佳分选条件下,经过“一粗一精”开路磁选工艺流程,所得精矿产品铁品位由25.40%提升至41.08%,提升幅度较大,铁回收率37.40%接近理论回收率,有害元素S、P和As含量较低,满足了对精矿产品的质量要求,选别指标理想。采用脉动高梯度磁选工艺选别该类铁矿石,选别工艺简单、分选指标好,为低品位、弱磁性铁矿石的回收利用提供了有效的分选方案。