浮选气泡粒度分布规律

定量研究不同起泡剂的气泡粒度分布特性及其差异,选择仲辛醇、松油醇和MIBC等起泡剂,在XDF-2L实验室浮选机上利用图像分析法测定了不同类型起泡剂下气泡的粒度大小,研究了起泡剂类型和浓度对气泡粒度分布的影响。结果表明,浮选槽中不同起泡剂在不同浓度下的气泡粒度分布遵循upper-limit分布或对数正态分布规律;起泡剂种类和浓度均会影响气泡粒度分布;随起泡剂浓度的增加,小气泡所占比例迅速增多,大气泡明显减少,粒度范围变窄,当超过临界值时,气泡粒度分布基本不变;仲辛醇、松油醇和MIBC的临界兼并浓度分别为0.066,0.113和0.181 mmol/L;当起泡剂浓度大于临界兼并浓度时,仲辛醇和松油醇产生的气泡大小略低于MIBC。     

机械搅拌式浮选装置中气泡粒径分布规律

为研究机械搅拌式浮选装置各可变操作参数对气泡分布特征的影响规律,选择仲辛醇作为起泡剂,利用图像分析法测定了不同条件下气泡的粒径分布,同时采用表面张力仪测定了不同条件下的表面张力。研究表明,随着药剂浓度由0.011 mmol/L逐渐增大到0.154 mmol/L,表面张力由73.577 mN/m线性减小到72.544 mN/m,气泡粒径逐渐减小,当达到临界兼并浓度0.103 mmol/L时,气泡粒径稳定于0.593 mm,仲辛醇的吸附浓度约为0.255 μmol/m2。气泡粒径随着叶轮转速(1 494～2 494 r/min)的增大而线性减小,且药剂浓度越大,气泡粒径降幅越小。随着吸气量由0.1 L/min增大到0.9 L/min,气泡粒径逐渐增大,且药剂浓度越低,气泡粒径增幅越大。气泡上升过程中其粒径随着取样高度(0～20 cm)线性增大,但药剂浓度越高,气泡粒径增幅越小。在各操作参数的研究范围内,药剂浓度小于等于临界兼并浓度时,取样高度对气泡粒径影响最显著,药剂浓度高于临界兼并浓度时,吸气量对气泡粒径影响最显著,而叶轮转速对气泡粒径影响最不显著。     

双余弦自吸气淹没喷嘴气泡粒径分布规律

根据引射吸气方式设计了一种双余弦自吸气喷嘴,为解析该喷嘴在不同操作因素下的气泡粒径分布特征规律。选择甲基异丁基甲醇(MIBC)作为起泡剂,利用图像分析法测量了不同起泡剂浓度、入流压力、喷嘴距、不同深度下的气泡粒径分布,分析了不同入流压力下喷嘴的吸气能力。结果表明:随起泡剂浓度的增大,气泡Sauter直径逐渐减小,当浓度达到临界兼并浓度0.112 mmol/L时,气泡粒径稳定于某个常数值,且入流压力越大,常数值越小,气泡粒径分布范围越窄,小气泡含量增大,如入流压力P=0.14 MPa时,气泡Sauter直径为0.32 mm,中间粒径气泡含量为40.73%;气泡直径随入流压力的增大逐渐减小,随喷嘴距增大逐渐减小,随不同深度增加线性增大,且药剂浓度达到临界兼并浓度时,减小(增加)趋势均变缓慢;吸气量随入流压力增大线性增大,且喷嘴距越大吸气量越大。     

Bubble size as a function of impeller speed in a self-aeration laboratory flotation cell

The effect of impeller speed (power consumption) on bubble size in a self-aerated Denver laboratory flotation cell was measured. The bubble size increases with increasing impeller speed. The explanation is that the accompanying increase in gas rate causes an increase in bubble size that more than offsets any effect of increasing shear.     

Improving particle size measurement using multi-flash imaging

An accurate calculation of the size distribution of coarse particles is crucial in the mining and quarrying industry. Machine vision has the capability to overcome many inherent limitations of traditional sieving methods and is an active research area. However, inaccurate image segmentation of particles through software based algorithms is a significant source of error. In this paper, a hardware based approach to improving image segmentation is demonstrated using multi-flash Imaging (MFI), where multiple images captured with different illumination allows depth edges around a particle to be captured through shadow information. The MFI method is compared with conventional segmentation methods such as watershed and Canny edge detection. In order to provide more accurate evaluation of performance wooden spheres of known diameter were evaluated. Imaging the size distribution of pebbles provided a practical scenario in the evaluation of MFI. The results revealed that MFI produced more accurate size estimations than conventional segmentation techniques for both the wooden spheres and pebbles, demonstrating the potential for future use in the mining industry.     

The removal of zinc from liquid streams by electroflotation

The removal of heavy metals from dilute aqueous solutions (in the range of 10⁻⁷–10⁻⁴ mol dm⁻³) is often not acceptable using classical methods, which do not achieve levels in accordance with environmental quality standards. Electroflotation has certain desirable characteristics, compared to dissolved and dispersed air flotation, particularly in regard to the small bubble size distribution of the process. The aim of this work was to develop an electroflotation (EF)/electrocoagulation (EC) cell to study this combined process and the influence of some relevant parameters/variables, such as collector concentration, tension and current density variation, on the removal of zinc from synthetic solutions containing 20 mg l⁻¹ of the metal. A platinum gore (5 mm) anode and stainless steel mesh cathode were used in the electroflotation cell. The work showed that it was possible to remove zinc by electroflotation, 96% removal being achieved using sodium dodecyl sulfate (SDS) as collector in the stoichiometric ratio 1:3, current density of around 8 mA/cm² and an inlet pH of about 7.0.     

图像处理技术在矿石粒度检测中的应用

矿石粒度对碎磨工艺具有重要意义,常规的检测方法步骤多、耗时长。基于图像处理的矿石粒度检测系统具有检测快速、结果稳定的优点。本文详细介绍了矿石粒度检测中所涉及的图像处理方法,在实际生产过程中,选取合适的矿石粒度检测方法,对于提高磨碎作业的技术水平以及实现自动控制都具有重要的意义。     

气泡、油泡和活性油质气泡在浮选中的应用和机理探讨

浮选是高效回收矿产资源应用最广泛的技术方法。气泡作为浮选载体在浮选过程中有着举足轻重的作用。以气泡-油泡-活性油质气泡为线索,对比了传统气泡与改性后油泡(气泡表层包裹一薄层油性捕收剂)、活性油质气泡(气泡表层包裹一薄层含有捕收剂的中性油)的浮选特性。通过浮选动力学分析了气泡与油泡、活性油质气泡浮选的区别,传统气泡浮选与改性后的油泡浮选均为2步反应,而活性油质气泡实现了1步浮选,大大降低了气泡与矿物颗粒间的黏附功,提高了浮选效率。从油-水界面表面活性剂解离度这个角度分析了活性油质气泡的表面性质,指出活性油质气泡的表面电性由表层中性油中添加的捕收剂和p H决定。通过DLVO理论计算了不同气泡与矿物颗粒间的相互作用能,从理论上解释了活性油质气泡浮选指标更好的原因。活性油质气泡在选矿中的成功应用表明,活性油质气泡与矿物表面的作用均强于传统气泡与矿物表面的作用,即活性油质气泡对矿物具有更强的捕收能力,相较于气泡和油泡的浮选,活性油质气泡浮选有利于提高浮选效率,降低捕收剂用量。活性油质气泡作为浮选载体从气泡这一特殊视觉为浮选行业开辟了一个崭新的研究领域。     

煤粉粒度测试技术现状及发展

介绍了目前国内外有关煤粉粒度分布测试技术的各种手段和方法,综合评述了其技术现状和特点,比较了各种测试方法的优缺点.     

基于K-means的金属矿物光片嵌布粒度测量

目前金属矿物嵌布粒度的测定主要依靠技术人员在显微镜下观测,存在工作量大、观测粒度准确度和精度不高等问题。因此提出了基于K-means聚类算法的金属矿物嵌布粒度测量方法。K-means算法初始聚类中心数K值的准确预设是本方法的核心之一,本项目对此开展了深入研究,发现利用金属矿物光片显微镜下图像中的颜色特征,对原矿图像中的矿物种类进行准确判别,再将识别到的矿物颜色特征作为设置K值的依据。通过K-means算法将目的矿物的颜色聚类为单一的颜色,对聚类的图像进行颜色分割,最后利用Feret Diameter精确测量出该金属矿物嵌布粒度。结果表明：该方法明显提高了金属矿物嵌布粒度测量的准确度、精度和效率,具有极大的应用价值。     

高气泡表面积通量充气器气泡特征参数试验研究

充气器生成气泡的特征参数是影响气泡表面积通量的关键因素。利用电导探针法和拍照测径法获取了充气器产生气泡的直径、速度及其分布特征。利用CCD高速相机获取了充气器的气泡分散特征。结合浮选柱的清水试验研究,分析了充气器喷嘴直径和充气压力两个关键参数对气泡特征参数影响。研究表明,KYZ浮选柱充气器能形成高气泡表面积通量的柱内分选环境。工业应用表明,KYZ浮选柱高气泡表面积通量充气器能够实现优异的分选性能。     

上湾选煤厂煤泥水在线粒度浓度测量系统的设计

粒度、浓度是选煤厂生产过程中煤泥水的关键参数,实现两个参数的在线测量对选煤厂生产调控和智能化建设具有积极的推进作用。本文根据上湾选煤厂工艺流程和设备布置特点,同时借鉴有色金属选矿厂矿浆粒度浓度测量的实践经验,选取了洗煤流程中的4个关键测量点,设计了4套煤泥水在线取样系统,通过1台四流道的BPSM-IV粒度浓度分析仪实现4个点煤泥水粒度、浓度的在线测量。     

气-固流化床气泡行为研究进展

本文综述了气固流化床中有关气泡行为的研究概况及最新进展.对气泡的生成、形状、上升速度、尺寸及控制等方面不同的研究结果之间的差异和可能原因进行了分析.最后指出了该领域进一步研究的课题及方向.     

浮选气泡矿化机理研究

简要阐述了浮选过程中气泡矿化的形式及阶段,解析了气泡和矿粒表面的粘附机理以及其过程中受热力学、动力学和时间分布等因素的影响,深入地了解气泡在三相体系中的矿化机理,为今后对浮选工艺的改进提供了基本依据.     

微泡发生器的数值模拟分析

首先详述了射流微泡发生器的结构和工作原理,分析、研究了射流微泡发生器的工作过程,其次借助FLUENT软件分析了发生器内三相流场内流体的运动状态。通过对流体运动的模拟分析,发现设计的缺陷,并对各参数进行了优化,通过对射流微泡发生器的模拟分析,为设计提供了依据。     

Bubble spargers in column flotation: Adaptation to precipitate flotation

The limiting factor for metal-organic precipitate flotation in a column is the level of aggregate stability under the turbulence created by the rising bubbles. The hydrodynamic conditions in a 75 mm diameter pilot column were optimised by using different bubble spargers (Microcel, Flotaire, Imox) and by varying the gas flow rate into the bubble sparger, feed flow rate in the column, type and concentration of frother and recirculating pump flow rate. With the bubble spargers used, the average bubble diameter ranges from 0.30 and 1.10 mm, with up to 25% gas hold-up. The parameters influencing average bubble diameter are the superficial gas velocity and the recirculating pump flow rate. For optimal concentrations (10 to 20 mg/1), the type of frother has a negligible role.Strong interaction occurs between superficial gas and feed velocities and recirculating pump flow rate for bubble size control. The optimum operating conditions must accordingly be maintained to prevent carryover of small bubbles into the recirculating pump or the purified solution. An example of the Mo precipitate flotation confirms the assumption made for the effect of bubble size and dissipation energy on the separation results. reserved.     

松油醇液相体系中气泡的特性研究

为了研究气泡在松油醇体系中的行为变化,以不同浓度松油醇液相体系中产生的气泡为研究对象,利用高速摄像和图形图像识别系统对气泡进行形心位置和圆形度的识别,进而分析松油醇浓度对气泡直径、直径概率分布、气泡的圆形度、气泡速度等的影响。实验结果表明：松油醇浓度越大,气泡直径两极化分布越明显,从直径概率分布来看,气泡直径分布呈双峰分布|在松油醇浓度大于0.14%时,气泡的圆形度处于小形变区|松油醇浓度不同时,气泡呈现不同的速度,总体上分布在0.3m/s到0.55m/s之间,且呈现周期性变化。     

小型浮选柱中气泡运动的PIV测量方法

以旋流-静态微泡浮选柱柱段区域测量为例,使用PIV技术对其内的气泡运动进行了测量,得到了气泡运动的速度矢量图,并且达到了较高的测量精度。