Multi-stage Electrostatic Separation for Recovering of Aluminum from Fine Granules of Black Dross

Separation of aluminum from fine granules of black dross, which is a waste by-product in secondary aluminum production, was investigated. The separation was performed by a multi-stage electrostatic separation method. There are three stages to complete the separation, including preliminary separation, pulse charging enhancement and secondary concentration. Chemical and mineralogical compositions of collection products were analyzed and determined by X-ray diffraction(XRD) and X-ray Fluorescence(XRF). After multistage electrostatic separation, the Al2O3 content of the collection products increases from 50.74% to 69.77%.The mineralogical phase analysis indicates that the final recovery of metallic aluminum phase increases from 8%to 37%, and the aluminum oxide phase increases from 20% to 26%. The research results show the multi-stage electrostatic separation method is effective for recovering of aluminum from fine granules of black dross, and upgrades the black dross to a recoverable material.

Evaluation of VSK separation in the classification of two mineralogically different iron ore fines

With gradually diminishing Fe grade in tandem with the ever-increasing demand for high-grade iron ores,iron ore industries are now focusing on the beneficiation of low-grade iron ore fines,mainly considered waste.Besides,the scarcity of water at many of the mines’sites and the new water conservation policies of the governments have necessitated research on suitable dry beneficiation routes.In this context,an effort has been made to evaluate the efficacy of a dry classification unit,such as the VSK separator,in upgrading the iron values of two low-grade Indian iron ore fines,named Sample 1 and Sample 2.The mineralogical studies,involving scanning electron microscopy and X-ray diffraction,suggest that Sample 1 is a low-grade blue dust sample(51.2wt%Fe)containing hematite and quartz as the major minerals,while Sample 2(53.3wt%Fe)shows the presence of goethite in addition to hematite and quartz.The experiments,carried out using Box-Benkhen statistical design,indicate that blower speed,followed by feed rate,is the most influencing operating parameter in obtaining a good product in the VSK separator.At optimum levels of the operating factors,a fines product with~55wt%Fe at a yield of~40%can be obtained from Sample 1,while Sample 2 can be upgraded to~56wt%Fe at a yield of~85%.The results suggest that the VSK separator can be employed as an efficient intermediate unit operation in a processing circuit to upgrade the iron contents of iron ore fines.

Ferronickel enrichment by fine particle reduction and magnetic separation from nickel laterite ore

Ferronickel enrichment and extraction from nickel laterite ore were studied through reduction and magnetic separation. Reduction experiments were performed using hydrogen and carbon monoxide as reductants at different temperatures （700-1000℃）. Magnetic separa- tion of the reduced products was conducted using a SLon-100 cycle pulsating magnetic separator （1.2 T）. Composition analysis indicates that the nickel laterite ore contains a total iron content of 22.50wt% and a total nickel content of 1.91wt%. Its mineral composition mainly con- sists of serpentine, hortonolite, and goethite. During the reduction process, the grade of nickel and iron in the products increases with in- creasing reduction temperature. Although a higher temperature is more favorable for reduction, the temperature exceeding 1000℃ results in sintering of the products, preventing magnetic separation. After magnetic separation, the maximum total nickel and iron concentrations are 5.43wt% and 56.86wt%, and the corresponding recovery rates are 84.38% and 53.76%, respectively.

New Technologies of Combined Agglomeration-separationfor Wolframite Fines

The new technology of combined agglomeration-separation and conditions for treating wolframite fineswere discussed. A mixture of wolframite and four kinds of gangue fines (quartz , fluorite, garnet and calcite)can be separated by this new technology. At high feed grade (wolframite : gangue = 1: 1) , wolframite con-centrate obtained by sedimentation assays 6 1 . 22 % ￣ 68. 33 % WO_3 with a recovery of 84. 4 % ￣93. 4 %. Atlow feed grade (wolframite : gangue =1 : 5) , wolframite ocncentrate obtained by combined agglomeration-separation and low-intensity magnetic separation assays 51 . 5% WO_3 with a recovery of 92. 0%. The majorfactors influencing these processes are the dosage of reagents and magnetite used, the time and the speed of agitation.

Experimental Research on Desulfurization of Fine Coal Using an Enhanced Centrifugal Gravity Separator

A desulphurization experimental study under the effects of compounding physical force fields has been de- scribed for < 0.5 mm fine particles of high sulfur coal. A statistical test using the Box-Behnken Design of experiments was conducted to evaluate the effects of individual operating variables and their interactions on desulfurization of fine coal using an enhanced centrifugal gravity separator. A model describing the relation between desulphurization effi- ciency of pyrite sulfur and different operating variables has been designed. The interactions between different factors on the pyrite sulfur desulphurization efficiency have been analysed. The optimal test conditions for desulfarization are ex- tracted from the Design-Expert 6.0 software. Finally, the advantage of centrifugal gravity separation for fine coal is pointed out.

Effect of bubbles addition on teetered bed separation

To improve the separation efficiency of a conventional Teetered Bed Separator(TBS) in beneficiation of fine coal with a wide size range,an Aeration TBS(A-TBS) was proposed in this investigation.The bubbles were introduced to A-TBS by a self-priming micro-bubble generator.This study theoretically analyzed the effect of bubbles on the difference in hindered settling terminal velocity between different density particles,investigated the impact of superficial water velocity(V_(SW)) and superficial gas velocity(V_(Sg)) on bed fluidization,and compared the performance of the TBS and A-TBS in treating 1-0.25 mm size fraction particles.The results show that the expansion degree of fluidized bed which was formed by different size particles or has different initial height,is increased by the introduction of bubbles.Compared with the TBS,at the same level of clean coal ash content,the A-TBS shows an increase in the combustible recovery of clean coal,ash content of tailings,and practical separation density by 5.26%,6.56%,and 0.088 g/cm3 respectively,while it shows a decrease in the probable error(E_p) and V_(SW) by 0.031 and 3.51 mm/s,respectively.The addition of bubbles at a proper amount not only improves the separation performance of TBS,but also reduces the upward water velocity.

THE STUDY OF THE BASIC THEORY AND THE APPLICATION OF REMOVAL PYRITE AND ASH FROM FINE COAL WITH ELECTROSTATIC SEPARATOR

The effect of removing pyrite and ash ffom fine coal with electrostatic separator is determined by the electric property of coal, the distribution of corona ion and etectrostatic field, and the disperse and even feed. The dielectric constant of coal and mineral matter is studied in this paper and the amendment has been made to survey theory. The oscillogram is adopted to study the distribution of corona ion and electrostatic field.The paper details the study of remoing pyrite and ash from fine coal, and the test results demonstrate the high efficiency of removing pyrite and ash with electrostatic separator.

Triboelectrostatic Separation-an Efficient Method of Producing Low Ash Clean Coal

At present, coal is mainly consumed as fuel. In fact, coal is also a kind of precious raw material in chemical industry on the premise that some harmful minerals should be removed from coal. The paper presents the results of the research on producing low ash (<2%) coal with triboelectrostatic separator used for producing high-grade active carbon. The test is conducted in bench-scale system, whose capacity is 30～100 kg/h. The results indicate that: 1) the ash content of clean coal increases with the increase of solid content of feedstock, on the contrary, the yield of clean coal is declining; 2) a high velocity may result in a good separation efficiency; 3) for the same solid content, the reunion caused by intermolecular force makes the separation efficiency drop down when the ultra-fine coal is separated; 4) the separation efficiency is improved with the increase of electric field intensity, but there is a good optimized match between the electric field intensity and yield of clean coal; 5) a low rank coal is easy-to-wash in triboelectrostatic separation process; 6) the yield of clean coal can be enhanced and the ash decreased through adapting optimized conditions according to various coals.

Removal of Silica and Alumina as Impurities from Low-Grade Iron Ore Using Wet High-Intensity Magnetic Separation and Reverse Flotation

This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.

细粉物料干式磁选机的国内发展现状

与湿式磁选相比,干式磁选具有节省水资源、选矿流程短、设备投资少、占地面积少、选矿成本低等优势。我国的铁矿资源品位越来越低、嵌布粒度细,亟需开发细粒级物料干式磁选机。根据现有各种型式干式磁选机的结构和工作原理将其分为磁重联合干式磁选机、直接给料风重磁联合干选机、风力送料干式磁选机等。磁重联合干式磁选机主要有固定磁系筒型干式磁选机、干式对辊强磁选机、带式旋转磁场干式磁选机、双环形移动磁系干式磁选机、干法强磁板式磁选机、干法筛式强磁选机、振动高梯度干式磁选机等典型型式。直接给料风重磁联合干选机主要有风力滚筒干式磁选机、风力带式干法磁选机、筒式流态化干式磁选机、三级干式永磁筒式磁选机、风磁耦合干式磁选机、干式风力磁选机、风重磁联合力场磁选机等典型型式。风力送料干式磁选机主要有风力送料板式磁选机、新型干式风磁联合磁选机、干式风力永磁精选矿机、风力给料干式永磁磁选机等型式。对以上20余种干式磁选机的结构、磁选原理、特点、适用范围等进行了介绍,并对各类干式磁选机的优势和劣势进行了分析。

潮湿细粒煤复合式干法分选特性研究

为研究潮湿细粒煤复合式干法分选效率,对潮湿细粒煤进行了振动强度和气速的单因素试验,结合RSM-BBD预测模型获得了最优参数;并探索了不同水分的原煤在不同分选时间内的分选效果,同时分析了气流对潮湿细粒煤分选过程的影响,并评价了分选效果。结果表明:随着分选时长的增加,分选效果明显提高,最大灰分离析度可达12.05。试验煤样在气速为0.78 m/s,振动频率为25 Hz,振幅为3 mm时达到最佳分选效果,此时可能偏差E=0.135 g/cm^(3),且在此条件下分选产品有很好的脱水效果,复合式干法分选可实现潮湿煤炭的提质。该研究可以对细粒煤炭的干法分选工艺提供理论和技术支持。

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。

煤气化细渣疏水-亲水双液炭/灰分离实验

这是一篇矿业工程领域的论文。煤气化细渣是煤气化过程中产生的一种固体废物,其中残炭严重制约了其资源化利用,从煤气化细渣中提取残炭是一个紧迫的问题。本研究应用疏水-亲水双液分离技术来提取煤气化细渣中残碳,其主要的影响因素有搅拌速度、搅拌时间、疏水液体用量、矿浆浓度、矿浆温度和疏水液体种类。疏水-亲水双液分离技术对煤气化细渣有优异的提碳降灰效果,其碳产品的灰分可达30%以下,灰质产品的灰分可达95%以上。通过表征分析揭示了分离机理,结果表明残炭对煤油的吸附强度远超灰质,使得煤油处理过的残炭疏水性大幅度增加,容易被油相捕获。本研究可为煤气化细渣的高效提碳降灰提供重要指导,有助于实现煤气化固废的综合利用。

微细粒矿物选择性絮凝理论与技术进展

我国有大量难处理的微细粒矿产资源,选择性絮凝技术是提高微细粒矿物回收的有效途径之一。首先分析了微细粒矿物的性质及其难浮选的原因,其次阐述了选择性絮凝的相关理论研究进展,最后对目前常见的选择性高分子絮凝剂进行分类,并对絮凝剂和选择性絮凝分选工艺在微细粒矿物分选中的研究和应用现状进行了分析和总结,认为絮凝剂选择性较弱、成本偏高、会产生环境影响、絮凝设备缺乏等是目前存在的主要问题,指出开发选择性强的新型絮凝剂、絮凝设备和絮凝工艺是未来的发展趋势。

米糠制粒浸出工艺的研究与实践

旨在验证改进型糠粞分离器的分离效果和为米糠制粒浸出工艺提供一定的技术参考,采用风选分离糠粞、制粒烘干、平转浸出、负压蒸发、DTDC湿粕脱溶的米糠制粒浸出工艺制取米糠原油,通过总结生产中的一些问题和操作经验,改进了风选式糠粞分离器,确定了颗粒化处理方式及米糠制粒浸出工艺关键点的参数。结果表明:采用改进的糠粞分离器,糠粞分离效果良好,处理量大;以低温制粒烘干代替膨化进行米糠的颗粒化处理,米糠制粒浸出工艺关键点的工艺参数为制粒温度60℃,颗粒直径3.7 mm,烘干机出料温度60℃,烘干后颗粒水分5%,浸出温度55℃,蒸发系统真空度70 kPa,第一蒸发器出油浓度85%、温度65℃,第二蒸发器出油浓度95%、温度98℃,汽提塔出油温度102℃,蒸脱机气相温度76℃。采用优化的米糠制粒浸出工艺可改善米糠原油及糠粕品质,并可降低能耗。

喷雾耦合降温强化旋风分离器脱除细颗粒物的研究

通过在冷凝换热器前耦合喷雾的方式,将雾化团聚和水汽相变团聚结合以提高旋风分离器对细颗粒物的脱除效果,用于湿式除尘器后近饱和高湿烟气的深度处理。通过开展实验室试验和某金属冶炼厂烟气旁路试验,考察了该技术对颗粒物的脱除特性。实验室研究结果表明,典型工况下喷雾耦合降温能够显著增强旋风分离器对颗粒物的脱除,比单独喷雾或降温具有更好的增强效果。提高喷雾量和换热器温降,细颗粒物脱除效率先升高后趋于稳定,在温降6℃、喷雾量0.046 L/m^(3)时达到最优脱除效果。烟气温度越高,湿度越接近饱和,细颗粒物脱除效率越高。工业烟气旁路试验表明,该系统适用于湿式除尘后的近饱和高湿烟气,且对波动工况的适应性强,当入口颗粒物浓度不超过2000 mg/m^(3)时,出口颗粒物浓度可保持在20 mg/m^(3)以内,平均脱除效率超过99.2%。

RefluxClassifier分离细颗粒的技术发展与应用前景

矿石综采技术带来诸多便利的同时,也导致了矿石中细颗粒比例增多。细颗粒分离成为了国内外矿物加工领域面临的难题。由于细颗粒质量小、比表面积大、表面能高、容易团聚,进而难以有效分离。本世纪初,由澳大利亚学者Galvin所研制的RefluxClassifier(回流分级机,简称RC)作为一种新型重力分选设备进入到矿物加工设备行列。该设备由液固流化床与倾斜通道组成,分为垂直段与倾斜段,具有操作简单、成本低廉和高效节能等优点。据研究,RC因其特殊的结构与工作机理可以有效解决细颗粒分离问题。本文首先归纳了国内外有关RC的理论研究,详细描述了RC倾斜段中颗粒在流体中的运动状态,阐明了倾斜通道内颗粒运动与流体流动特性之间的关系,简要分析了颗粒性质与流体之间的力与速度关系。此外,本文对目前现有RC的水速预测模型(经典动力学模型、经验模型、弱化粒度模型、平衡模型)进行了总结,并综合分析了各模型的适用范围。结合试验案例,介绍了RC在煤炭、黑金属、砂石骨料等领域的应用现状,举例分析不同试验条件下RC对细颗粒回收的分离情况。最后结合我国资源现状与现代设备发展趋势,提出如何深入优化RC分选理论模型、拓展更广阔的应用领域是国内外学者的长期研究目标,并展望RC在工业范围内的全面推广。

云南某贫细硫化铜矿石选矿工艺优化研究

云南某低品位细粒嵌布的铜矿石铜、硫品位分别为0.161%和9.704%,有价铜矿物嵌布粒度细,铜硫分离富集难度较大。为实现该硫化铜矿石资源的高效开发利用,在选厂原选矿流程及原矿工艺矿物学研究基础上,进行了系统的磨浮试验。结果表明:矿石采用磨矿—1粗2扫铜硫混合浮选—混浮粗精矿再磨—1粗3精2扫铜硫分离浮选闭路流程处理,可获得铜品位14.69%、铜回收率63.15%的铜精矿,硫品位29.16%、硫回收率75.10%的硫精矿,试验铜精矿品位较现场提高近3个百分点,铜回收率提高15个百分点以上,显著优于现场生产指标,达到了理想的综合回收铜硫效果。研究结果可作为工艺流程优化的依据。

动力煤选煤厂煤泥梯级提质及无量化研究

为了适应煤泥减量化的需求,以淮北桃园选煤厂动力煤为研究对象,基于煤泥粒度、密度和矿物组成分析,提出了三阶段煤泥减量化的技术路线,确定了粗煤泥重选和尾煤泥深度浮选的梯级降灰提质以及细煤泥新型压滤机降水提质方案。研究结果表明:粗煤泥分别采用干扰床分选机和螺旋分选机进行分选试验,以螺旋分选粗精煤产率更高,产率为88.82%,灰分为23.05%;尾煤泥采用一次浮选回收,当药剂用量为0.45kg/t,入料浓度为90g/L时,精煤产率为41.31%,灰分为15.74%,发热量可提高到20.97MJ/kg。经过粗煤泥分选、尾煤泥浮选以及细煤泥脱水,粗精煤和精煤泥的发热量分别提高了23.50%,65.30%,煤泥经降水后可全部回掺,其掺混后商品煤发热量为21.32MJ/kg,实现了动力煤选煤厂的煤泥无量化。

某金矿尾矿再磨再选半工业试验研究

某金矿矿石性质复杂,泥化严重,氧化率高,金嵌布粒度微细,载金矿物种类多,硬度及解离度差异大,属复杂难处理金矿,经重选+阶段磨矿阶段浮选联合选别流程,尾矿平均金品位0.8 g/t,金大部分以包裹金形式损失。采用艾砂磨机+微泡浮选机对现场尾矿进行高效细磨细选,取得了精矿金品位16 g/t、金回收率30%以上的选别指标。该研究成果部分已经应用于生产,并取得了显著的经济效益,为复杂难处理金矿开发及尾矿综合利用提供了一条有效途径。