实时在线颗粒分析技术在选矿行业的应用

实时在线颗粒分析技术在选矿行业中的应用梅特勒-托利多和您我们殷切地期望成为您精密仪器解决方案的唯一供应商。

全球著名纽约上市公司11’200名员工年销售额超过23亿美金梅特勒-托利多集团工业过程检测包装检测实验室零售业实验室实验室零售业工业过程检测包装检测液体分析称量移液器热分析自动化化学梅特勒-托利多实时在线颗粒分析技术梅特勒-托利多是原位条件下监控和测量颗粒和液滴的世界领导者梅特勒-托利多在颗粒体系表征方面拥有超过25年的革新技术我们全球的应用顾问团队具有超过2500台的实际安装应用经验，主要支持结晶、乳化、悬浮、选矿等多方面的颗粒及多相体系的应用全世界超过5000 名的科学家和工程师使用了该项技术Redmond, Washington, USA目录实时在线颗粒分析技术介绍 应用案例PVM® 技术颗粒录影显微镜技术P article V ideo M icroscope 显微镜质量、实时在线记录颗粒的图象信息 颗粒测量范围从2微米至1毫米FBRM ® 技术聚焦光束反射测量技术F ocused B eam R eflectance M easurement 在当前工艺条件下，实时原位在线追踪颗粒和液滴的变化情况颗粒测量范围从0.5 微米至3 毫米10 µm液滴实时在线颗粒分析技术从实验室到工厂的安装基于探头的技术，不需要取样，不需要样品制备针对颗粒体系瞬间实时响应工艺的变化安装于10mL 至20,000 L，管道、高压、危险、恶劣的环境中PVM ®技术没有额外照明的要求探头由耐化学腐蚀的材料制成（哈氏合金Alloy C22及蓝宝石窗口）紧密的焦平面所获得高精度的图片，将背景颗粒的影响减到最少 即使在快速移动的流体中，也能获得清晰的图片而不会产生模糊蓝宝石窗口照明透镜系统物镜CCD 导管CCD Camera在极端条件下高精度的图像PVM®能在极端条件下获得高精度的图像信息:8在特别粘稠或不透明的体系下，或者8在极端低或者非常高的温度和压力下8此时，不能取样PVM®增强型视窗下原油中的水PVM®测量原油中的气体水合物有机晶体11PVM® 立刻揭示聚结过程The Use of In Situ Analytics for Crystallization Process DevelopmentBrian O’Sullivan, Ph.D. Thesis, University College Dublin, 2005在线 PVM ® 图像：Crystallization midpointCrystallization endpoint离线 显微镜图像：之后： 1.过滤 2.干燥 3.制样12FBRM® 聚焦光束反射测量仪FBRM® 是一个定量化的测量工具，使化学家或工程师迅速将颗粒体系的动态变 化同工艺条件相联系。

在原位工艺条件下，追踪颗粒及液滴的变化程度和变化速率FBRM® 能直接测量颗粒的粒径、形状及数量 运用在线数据能帮助理解并优化动态过程-无需取样 固含量达到70% 实验室或者工厂环境 透明或者不透明的料液中 从亚微米至毫米实验室中试及工厂13管道FBRM® 测量方法FBRM® 在线探头的剖视图 PVM® 图像说明 FBRM® 探头 窗口看到的情况激光光源光纤 监测光纤 电子光束分裂器旋转棱镜组 FBRM® 探头导管 合成蓝宝石 窗口安装于流体中的探头聚焦光束14FBRM® 测量方法放大视图 PVM® 图片表示 FBRM® 探头 窗口观测到的情况聚焦光束经过路线探头监测脉冲式的反射散 射光 并记录所测量的弦长15FBRM® 测量方法Enlarged view 放大图Path of Focused 聚焦光束的路径 BeamFBRM® 每秒钟测量数千个弦长，从而形成 弦长分布16在线颗粒分布以及趋势变化不加权分布 #/s <50 µm#/s 50-1000 µm不需要改变条件就能实现亚微米至 毫米级的测量 按照用户自定义的粒径范围进行随 时间趋势统计 无需校准就能测量小颗粒和大颗粒17冷却速率对小颗粒产生的影响小颗粒增加冷却结晶 1L 规模冷却速率增加搅拌 - 400rpm 在80ºC下饱和溶液FBRM® 立刻揭示第二阶段冷却斜率增加，产生更多小颗粒 （二次成核） 较短批次时间需要同之后的较长过滤干燥时间达到平衡 （冷却速率快，批次时间较短，但小颗粒更多，过滤干燥时 间更长） 设计颗粒分布能确保最有效的结晶过程18过程理解风险管理工艺改进/设计空间如何定量确定颗粒分布的变化？更多小颗粒通过研究相关颗粒分布定量揭示不同 工艺之间的差异19将颗粒分布同后续工艺相关联更多细颗粒20将颗粒分布同后续工艺相关联Statistics Isolation Point AIsolation Point B#/s <10μm 799312950Median (μm)12.989.6更多细颗粒目录实时在线颗粒分析技术介绍应用案例（CSIRO, Australian ）FBRM&PVM在尾矿处理中的应用矿石经过选别之后，将有大量尾矿产生，尾矿颗粒极细，多为泥浆状，难以沉淀，难以脱水。

尾矿沉淀池使尾矿水在池中进行沉淀，以达到澄清的目的。

尾矿水往往呈胶状，为了使尾矿水很快地澄清，可加入凝聚剂，以加速颗粒的沉淀。

优化尾矿沉降工艺在线监测不同粒径颗粒的凝聚过程提高沉淀分离的效率优化工艺适用最少的絮凝剂降低设备规模/pix/FlocculationProcess.jpgLuke Kirwan, Aughinish Alumina Limited尾矿泥浆中加入规格为2% wt/V 的高岭土作为凝聚剂。

不同加入量的PVM 图像8 g t -115 g t -130 g t -1100 μm没有加入高岭土尾矿泥浆中加入4.5wt%高岭土悬浊液为凝聚剂。

FBRM 监测加入不同量的高岭土的结果对照图。

0200400600800100012001101001000CountsChord length (祄)unflocculated3643525763Dosage (g t -1)0204060801001201401601101001000Square-weighted countsChord length (祄)3643525763Dosage (g t -1)unflocculatedInvestigating bauxite residue flocculation by hydroxamate and polyacrylate flocculatsutilizing the focused beam reflectance measurement probeCathy Zheng March. 2013Luke J.KirwanInt. J. Miner. Process. 90 (2009) 74–80利用FBRM 探头研究加入异羟肟酸和聚丙烯酸酯絮凝剂铝土矿残渣的絮凝过程Introduction: Bauxite residue flocculationExtraction of alumina from bauxite generates large volumes of residue (red mud).In gravity thickenerKey performance factors: underflow density底流密度, throughput, and overflow clarity 溢流澄清度.Flocculants Starch Polyacrylate HydroxamateAdvantage Good clarity throughput of the thickeners hasbeen significantly increased better overflow clarities,lower thickener rake torque,and less scaling within the thickenersDisadvantage notparticularlygoodthroughput have adetrimental effect on claritythe underflow density achievedmuch lower密度低Usage not usually employed alonecombination with starch(Connelly et al.,1986;Hunter etal.,1991)either usedexclusively,or in combination with polyacrylate,to eliminate starch usage1980Flocculants(a) Schematic representation of the repeat monomer unit within polyacrylate聚丙烯酸酯flocculant(b) the incorporation of the hydroxamate异羟肟酸functionality into an anionicpolyacrylamide 阴离子聚丙烯酰胺flocculant.Introduction: FBRMSettling tests, measure:1) the rate of decent of the mudline formed泥水分界线形成的速度;2) the clarity of the supernatant liquor in batch cylinder 母液澄清度From this measurement, properties of the aggregates formed can be inferred FBRM:offers the potential to measure aggregate size directlyFBRM is the only tool that will give a real-time, in situ indication, be shown to be a very useful tool in the study of mineral and process flocculation (e.g. Hecker et al., 1999; De Clercq et al., 2004).Chord Length Distribution differs from Particle Size DistributionSquare-weighted distribution is a more accurate representation of volume-weighting(Heath et al., 2002). Conventional sizing instruments, such as the Malvern Mastersizer.Introduction: FBRMAfter flocculant addition there is an increase, followed by a peak, and then a gradual decay. The mean square-weighted chord length achieved fromflocculation is proportional to the measured settling rate (Heath et al., 2006).The decay behaviour is indicative of aggregate break-up caused by the continually applied mixing to the system.The rate of decay has been found to be inversely proportional to the resistance of the aggregates to breakage. A very small rate of decay indicates strong aggregates, or additionally a high rate of dynamic re-flocculation (Blanco et al., 2002).FBRM has been integrated into this flocculation study to examine the comparative performance of process hydroxamate and polyacrylate flocculants on Bayer process bauxite residue slurry. The study has focussed on clarity and aggregate strength as key performance indicators.FBRM Data focused on aggregate strength After flocculant addition there is an increase, followed by a peak, and then a gradual decay. the mean square-weighted chord length achieved fromflocculation is proportional to the measured settling rate (Heath et al., 2006).The decay shows aggregate break-up caused by mixing.The decay is an exponential function (Alfano et al., 1999).The rate of decay is inversely proportional to the resistance of the aggregates to breakage.A very small rate of decay indicating strong aggregates, or additionally a high rate of dynamic reflocculation.(Blanco etMethodsWith settling test: 250ml, equilibrate 3 min, flocculant dose, stop stirrer; After 5min, 20ml sample determined gravimetricallyWithout settling test: 150ml, 95C, equilibrate 10 min, flocculant dose for a further 10min. If add starch, added 7.5 min after experiment started.Viscosity-concentrationHydroxamate flocculant: HX300Polyacrylate flocculant: 9779At a 9779 concentration of 0.06 % and a HX300concentration of 0.13 %, equivalent viscosities.Viscosity and hence mixing issues are not aconcern for the starch solution, therefore inexperiments where starch was used, it wasadded undiluted.FBRMThe decay shows aggregate break-up caused by mixing.The decay is an exponential function (Alfano et al., 1999).The rate of decay is inversely proportional to the resistance of the aggregates to breakage.A very small rate of decay indicating strong aggregates, or additionally a high rate of dynamic reflocculation.(BlancoFlocculation Studythere is an increase in the ‘max.size’ with increasing flocculantdosage and this correspondswith a decreasing trend in the1 –5 μm‘fine’ counts.However, it can also be seenthat several experiments havebeen repeated andreproducibility was often poor.However, such variations areinevitable with plant slurriesinvolving digestion andsupersaturation.FBRM From Table 1on the same general curve,regardless of flocculant added,agitation intensity, and whetherstarch was added or not.the addition of starch wouldappear to improve theperformance of the 9779polyacrylate flocculant.Settling testFigure 5: The relationshipbetween the gravimetricsolids left behind in thesupernatant after settlingfor 5 mins with(a) the FBRM 1 –5 μm‘fine’ counts/s and;(b) the maximum meansquare-weighted chordlength.HX gave visibly muchlarger aggregates, whichexhibited faster settling,and better fines capture incomparison to 9779HX offer a greater captureefficiencySupernatant SolidsHX300 flocculation were much harder to and appeared more red in coloured compared to those from 9779 flocculation.encouragingSEM imagesFigure 6: (a) SEM image of the thickener overflow solids from the thickener utilising HX300 feedwell flocculation and(b) the thickener using 9779 feedwell flocculation.Different Hydroxamate PolyacrylateFiner and more iron rich More coarse particlesAfterflocculationEDX能量色散X射线光谱仪Figure 7 shows that the solids from the HX300 treated thickener have relatively much higher amounts of iron, but relatively less amounts of titanium, calcium, and silicon.This aggregate breakage has been examined by fitting an exponential y = Co + A.exp(-x/Tb)Co is the final size;A + Co the initial size;1/Tb the rate of decay.Tb indicates a robust aggregate structureThe aggregates formed are more robustThe use of starch with 9779 did not appear to have an influenceIndustrial ApplicationThe key difference was found to be the way the aggregates developed post-shear, with hydroxamate flocculation exhibiting a greater degree of post-shear flocculation 后剪切絮凝.Different HydroxamatePolyacrylate AggregatesGreater fines capture More dense 密度Lower solids in the supernatant 上清液More shear resistantAfterflocculationFiner and more iron richMore coarse particles剪切絮凝是利用对矿浆进行较强烈搅拌而产生的剪切力和捕收剂在矿粒表面吸附所产生的疏水键合力，使微细矿粒形成絮团，进行分离回收的浮选方法。