浮选柱充气率的影响因素探讨

采用液位上升法,利用射流发泡器研究了充气速率和起泡剂浓度等操作参数对浮选柱充气率的影响规律。结果表明,浮选柱的充气率随着充气速率的增加急剧上升,随着起泡剂浓度的增加缓慢升高,两因素增加到一定值时,充气率达到最大值。     

浮选柱气泡发生器的研究与进展

介绍了浮选柱气泡发生器的研究与发展;论述了几种发泡方式及其优缺点;分析了各种内置发泡器和外置发泡器的结构类型和工作原理,比较了各种发泡器的优缺点及气泡尺寸情况。     

浮选柱发展历程及其在磷矿浮选中的应用现状

浮选柱的开发和应用已有120多年的历史,主要应用在煤和硫化矿的浮选,在磷矿选矿领域的应用相对较少。从浮选柱的发展历程、柱体结构、发泡器类型的介绍出发,围绕浮选柱类型和浮选柱浮选工艺详细阐述了浮选柱在磷矿选矿领域的应用,实践证明,浮选柱处理细粒级磷矿效果良好,具有较好的应用前景。     

充填静态浮选柱在胶磷矿浮选中的应用

考察了在充填式静态浮选柱中浮选低品位胶磷矿时,药剂用量、洗涤水加入位置及用量及各种操作因素对浮选结果的影响,得到了合适的浮选条件,为工业放大提供了依据。     

影响旋流微泡浮选柱工作因素的探讨

分析了旋流微泡浮选柱的工作原理以及影响浮选柱工作的各个因素;正交试验考察了入料浓度、循环压力和柱体高度三因素对浮选精煤灰分、产率及浮选完善指标影响的显著性;试验结果表明,影响程度大小的排序为循环压力最大,入料浓度居中,柱体高度最小。     

浮选柱结构及操作参数的探讨

介绍了实验室浮选柱分选五种煤泥的试验结果，证实浮选柱分选高灰细泥具有高度选择性，探讨了气泡发生器、喷洗水、浮选柱的高度和流态对分选效果的重要影响     

充填浮选柱正-反浮选胶磷矿工艺研究

通过充填浮选柱浮选胶磷矿的工艺实验,提出了串联操作的正一反浮选流程,得到了较为合适的工艺条件,为生产放大提供了理论依据。     

浮选柱作为胶磷矿浮选设备的前景

与搅拌式浮选机相比,浮选柱的优点是占地面积小、能耗低、比较适合于细粒矿物的浮选。 浮选柱的关键部件是气泡发生器。以往采用的微孔气泡发生器由于易被结垢堵塞、维修不便和所产生气泡的直径较大等缺点,使浮选柱难以推开。近年来,相继出现了冲孔盘式浮选柱、棒栅式浮选柱、充填式浮选柱和带外部气泡发生器的浮选柱,给浮选柱的工业应用开辟了广阔的前景。     

气含率与浮选动力学常数的研究

气含率大小是决定浮选柱回收能力和分选效果的重要参数之一,浮选柱内气含率直接决定了气泡荷载上浮矿物的数量与质量,从而决定了浮选过程中精矿的产率和回收率。本文考察了磷矿在充填浮选柱的浮选过程中,表观气体流速和矿浆质量分数对充填浮选柱捕集区气含率的影响。将浮选过程中的气含率与浮选动力学常数相联系,并结合充填浮选柱的工艺特征,推导出了具体的关联式。     

充填式浮选柱某些参数的相关关系研究

本文叙述了通过对充填式浮选柱模拟装置的测试，分析探讨了柱内的气泡直径与填料片波纹高度、起泡剂用量、充气量等因素之间的相关关系。     

环流浮选塔用于含油污水处理的实验研究

以空气/含柴油污水为模拟介质体系,在环流浮选塔(外筒体内径100 mm,高932 mm;导流筒内径59 mm,高780 mm)上考察了操作气速、液相流量及浮选塔上部空间填料设置对油-水分离效率的影响. 结果表明,分离效率随操作气速增大先增后降,随液体流量增大而降低;与传统空筒式浮选塔相比,环流浮选塔的分离效率比常规空筒式浮选塔有显著提高. 实验确定的最佳操作气速为0.015~0.02 m/s,最佳液相流量为20 L/h,在环流浮选塔上部设置填料的情况下,油-水分离效率最高可达57.3%. 基于实验数据建立了涉及气泡特性、液相物性、气液相流量及油滴返混影响因素在内的分离效率的经验模型,与实验值吻合较好.     

Experimental studies and numerical model validation of overflowing 2D foam to test flotation cell crowder designs

A computational fluid dynamics model of froth motion has been developed to assess different flotation cell designs. This work presents an implementation of the model in a 2D case, to compare the simulated bubble velocity distribution and streamlines to an experimental foaming system. The model uses finite elements to solve Laplace's equation for a potential function from which the foam velocity can be obtained. It requires the air recovery, or the amount of air that overflows a flotation cell as unburst bubbles, as an input parameter to calculate the foam velocity distribution and bubble streamlines. The air recovery was obtained by image analysis from a vertical, overflowing monolayer of foam (2D) created in a Hele-Shaw column, which mimicked important flowing properties of flotation froths such as coalescence. Inserts were included in the foam column to represent potential crowder designs for industrial flotation cells. Three different designs were chosen to compare the effect of insert depth and shape, including rectangles and a triangle. The effect of the insert design on the overflowing foam is obvious from visual assessment of the bubble streamlines and velocity distribution, which were closely agreed by both the experiment and model.     

The effect of air distribution on the induced air flotation of fine oil in water emulsions

The induced air flotation (IAF) of a highly stabilized oil in water (o/w) emulsion has been studied experimentally in a batch column 10 cm in diameter and 150 cm in height. Column performance was strongly affected by the method of air distribution. The main variables investigated were the type of air distributor (either porous plate, single hole plate, or multi-hole plate), initial oil concentraton (30-600 mg/L), oil drop size distribution of feed (1.0-30 μm), surfactant type, and gas superficial velocity. Results were successfully analyzed in terms of a first order kinetic rate model which yielded a removal rate constant (K₁) that varied from 2.0 to 60.0 h^?1. Corresponding total organic carbon (TOC) removal efficiencies went from 20 to 99.9 percent, illustrating the wide performance range for the flotation cell.     

A study of the bubble properties in the column flotation system

The bubble properties in the column flotation system are deeply affected by the bubble-generator type, frother dosage, and superficial gas velocity. This study is to determine the bubble-generator type, which effectively produces micro-bubbles to affect the flotation efficiency. Characteristics for two types of bubble generators like the in-line mixer and sparger are examined by bubble properties such as bubble diameter, holdup and bubble velocity. Micro bubbles generated from an in-line mixer result in the increase of the bubble rising velocity and gas holdup. Bubbles produced at the in-line mixer were more effective for operating the flotation system than that of the sparger. It means that the in-line mixer bubble generator is more effective than a sparger in designing or operating the column flotation system.     

脉冲萃取柱空气脉冲旋转阀的特性

对脉冲萃取柱的空气脉冲旋转阀产生的空气脉冲发生过程进行了分析,给出了其充气和排气过程特征,得到脉冲腿内液面在空气脉冲作用下随时间变化的理论模型,并将理论计算结果与大型空气脉冲旋转阀产生的脉冲压力变化及在其作用下在直径0.3 m、高5.6 m无筛板脉冲柱中产生的液体运动的实验结果进行了对比. 结果表明,空气脉冲旋转阀充放气时间很短,充气时间约0.2 s,放气时间不超过0.05 s,加压空气通过旋转阀后产生接近梯形波的空气脉冲压力,脉冲柱内液面随时间变化曲线为类似正弦形,理论模型计算与实验结果符合很好,验证了模型的可靠性.     

直接接触式冰浆生成器的单气泡传热特性

冰浆生成器是直接接触法冰浆制取系统的关键设备之一,而体积传热系数作为衡量冰浆生成器性能的重要参数受诸多因素影响。基于单个气泡在连续相中的上升特性,定性分析了各种因素对体积传热系数的影响。实验结果表明:进气温度下降、进气质量流量增加、水柱高度下降、喷嘴直径减小均导致体积传热系数增加。     

AN EXPERIMENTAL STUDY OF GAS HOLDUP IN TWO-PHASE BUBBLE COLUMNS WITH FOAMING LIQUIDS

Gas-liquid upward flow experiments have been performed in two bubble columns of different diameters (0.10 and 0.29 m,) using air as gas phase and several liquids: water, aqueous solutions of ethanol and glycerine, kerosene, and a solution of a surfactant in kerosene. The main goal of the study is the analysis of foaming systems, including the comparison of their behavior with respect to non-foaming systems. The gas holdup was determined experimentally as a function of the gas and liquid superficial velocities in bubbling, churn-turbulent and foaming regimes. It was found that, for foaming systems, semi-batch operation enhances foam formation, yielding higher holdups than those obtained in continuous operation at very low liquid velocities. Opposite to what is observed in non-foaming systems, the liquid superficial velocity affects the gas holdup appreciably in foaming systems. An increase in column diameter results in a decrease in gas holdup for all the systems studied. In aqueous foaming systems, this trend is more drastic since foam is inhibited as the column diameter increases.     

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions II: Continuous Mode of Operation

Abstract

The objective of this study was to investigate the relationship between interfacial tension (IFT) and foam characteristics and the efficiency of diesel oil removal from water in a continuous froth flotation column. The effects of operational parameters, including surfactant concentration, salinity, oil-to-water ratio, foam height, air flow rate, and hydraulic retention time (HRT) on the oil removal were investigated in the continuous mode of a froth flotation operation and compared to batch operation results. Unlike the batch system, for the continuous system used in the present study, having only branched alcohol propoxylate sulfate sodium salt surfactant (C_14–15(PO)₅SO₄Na) and NaCl present in the solution yielded such poor foam characteristics that a stable froth which overflowed the flotation column could not be produced, so the addition of sodium dodecyl sulfate (SDS) as a froth promoter was used to improve the foam stability. Unlike the batch froth flotation system with only C_14–15(PO)₅SO₄Na, the continuous froth flotation with the mixture of C_14–15(PO)₅SO₄Na and SDS, it was not possible to find a SDS and a NaCl concentration at which both ultralow IFT and good foaming were both achieved. Foam formation, stability, and production rate were found to be crucial parameters to the froth flotation efficiency. The continuous froth flotation system offers a high diesel oil removal of 96% in the single stage unit. Demonstration of efficient operation in the continuous mode in this work is important to the practical application of froth flotation in large scale processing.     

气浮塔处理含油废水的研究

在实验研究的基础上，结合单级气浮技术和多级板式塔理论，开发出两级气浮塔处理含油废水的新工艺，实现了塔釜一次曝气、多级气浮的分离。实验研究了气浮塔板的流体力学性能、布气性能及操作条件对废水处理效率的影响，结果表明二级气浮塔处理效果很好，是一种具有良好应用前景的新型含油废水处理装置。     

挡板式泡沫发生器内部流场分析

泡沫发生器是产生泡沫流体的设备,其发泡的基本原理是将空气引入发泡剂溶液中。应用数值模拟与PIV实验相结合,研究不同挡板角度对泡沫发生器内部气液两相流流动影响规律。该研究为疏松砂岩油藏冲砂洗井作业提供指导,为后续泡沫发生器结构设计提供理论依据。