混合物入选体积量对振动流化床分离特性的影响

利用计算机在线测量床层密度及分析颗粒在床层中的分布,考察入选体积量对流化床中床层密度及颗粒分离效率的影响。研究表明,当入选体积量的分选上限为２０％时,流化床才能对颗粒混合物进行有效的分选,并且在振动条件下比在非振动条件下的分选效率略高一些,这些研究结果对有振动重介质流化床分离细粒焦渣混合物具有一定的指导意义。     

工业焦渣混合物高效分离

中科院山西煤化所张济宇博士,采用空气重介质干法分选装置,成功地完成了“工业焦渣混合物的高效分离”试验。太化焦团公司化肥厂与煤化所协定将在化肥厂进行中间试验。     

从黄铁矿烧渣中回收铁的新工艺

硫铁矿焙烧后矿物晶形被破坏，质地疏松，呈微细粒嵌布，属难选矿物。采用简单的弱磁选和重选方法不能获得理想的分选指标。苏州硫酸厂烧渣采用细磨─酸洗─弱磁选─反浮选联合流程，可以从含铁５２．１５％的烧渣中分离出含铁５９．７５％的铁精矿，总回收率８２．７２％。为充分利用烧渣提供了新的途径。     

采用多次精选工艺浮选焦渣未燃煤的研究

由于经高炉高温燃烧后的高温焦渣和低温焦渣灰分均在46%以下,根据分步释放实验流程,设计了一次粗选多次精选的浮选工艺流程对焦渣进行分选,通过产品掺配能回收不同灰分指标的精煤;由于0.074 mm以下粒级含量的影响,高温焦渣浮选效果好于低温焦渣。     

基于视密度的煤气化渣水介质旋流炭-灰分离

煤气化利用过程中会产生大量气化渣,造成很大的环境污染,其综合利用势在必行。本文系统分析了煤气化渣不同密度组分的特性,明确了炭-灰分离是煤气化渣分质综合利用的前提与基础,并提出了基于视密度差异的炭-灰分离方法。以水介质旋流器为分选设备,通过单因素试验确定了主要工艺参数对炭-灰分离效果的影响规律,验证了水介质旋流分选对煤气化渣>0.074mm粒级炭-灰分离的可行性。借助Box-Behnken试验设计分析了旋流器锥体角度、底流口直径、溢流管插入筒体深度与产品灰分、产品产率及分选综合效率的定量关系,为煤气化渣炭-灰分离效果的预测及旋流器结构参数的选择提供了数据支持。本文研究内容对实现煤气化渣分质资源化利用具有指导意义。     

选择性絮凝在煤炭分选中的应用

介绍了选择性絮凝分选原理和选择性絮凝在煤炭分选中的应用研究。结果表明，该法既可对极细粒煤泥进行分选，又可制备洁净燃料，还可脱除单体解离的微细粒黄铁矿。用选择性絮凝对极细粒煤泥分选后，可得灰分１２％～１３％的精煤，可燃体回收率在９０％以上；两产品灰分差为５０％左右。制备洁净燃料时精煤灰分可小于３％，可燃体回收和产率均在９０％左右，最高值分别为９５．８８％和９４％。脱硫时，黄铁矿硫可从５．６９％降到０．５％以下，而且脱硫的同时可以脱灰，灰分可由１２．３％降至３％以下。     

硫酸渣除铜研究

江苏某化工厂排出的烧渣含铁一般50％左右，经我们试验，可将铁品位提高到61％，含硫则由0．96％降至0．34％。烧渣中还有1％左右的铜，必须使铜降至0．2％左右才可用作炼铁原料。为此，进行了除铜研究。l烧法样及研究方法烧渣呈黑灰色，疏松易碎，易团聚成蜂窝状。镜下观察，细粒石英浸染于赤铁矿、磁铁矿中，硬石膏和铜矿物也呈细粒嵌布于赤铁矿和磁铁矿中。烧渣的多元素分析和物相分析见表1、表人以上分析看出硫酸渣样中的矿物无明显的结晶面，分选的难度较大。矿样中的铜主要是结合氧化铜，采用常规的硫化黄药浮选法一酸浸法、离析一浮…     

云浮硫铁矿烧渣选矿试验

对云浮硫铁矿烧渣磨矿－弱磁选－阴离子反浮选试验流程、设备、工艺条件和试验结果作了介绍。在磨矿细度－２００目８８．４８％、原烧渣含铁品位４５．８７％的条件下，经磁－浮流程分选，获得综合铁精矿品位５５．４４％，回收率７７．９１％的指标。综合的尾矿品位含铁２８．５０％．     

系列药剂量分选超细粒煤试验研究

变化乳化药剂量进行超细粒煤的分选试验，贯穿运用3种细粒煤界面分选工艺方法；通过控制加药量，从少油量的泡沫浮选过渡到稍多油量的选择性疏水聚团，再逐渐增加油量，一直到大油量的油团聚，通过观察测量絮团大小，分析测定产物灰分、收率，寻找从小油量到大油量这整个过程所涉及的分选行为关系规律，此过程的研究对于细粒煤界面分选最佳条件的选择具有参考意义。     

环流旋流器的结构与性能研究

以细沙和水的混合物作实验物系,分别对4种不同结构尺寸的旋流器进行了研究．测定了不同操作条件的压降和分离效率?实验结果表明,带分离柱的环流式旋流器压降最低,效率最高。由该旋流器的粒级效率曲线可以看出,直径小于5μm的颗粒,由于比较容易被大颗粒夹带分离,其分离效率比7．5μm左右颗粒高。     

5500t/d顶级旋风预热器的综合研究与评述

本文通过冷态模型试验,结合实际生产参数的测定,对JY厂洪堡型顶部旋风预热器进行了系统研究。研究表明,在设计产量时,由于其流场的分布特点,该旋风筒具有比较理想的气固分离效果;但阻力相对较高,分离效率受风速影响较大,在提高系统产能时分离效果会明显降低,这些与实际生产情况都是相吻合的。     

Density-dependent separation of dry fine coal in a vibrated fluidized bed

The main purpose of coal separation is to reduce ash, sulfur, mercury and other mineral contaminants in the coal to increase the calorific value and benefit the environment. Dry coal beneficiation has obvious advantages over the wet process although the latter is currently the predominant method in use throughout the world. A vibrated fluidized bed was constructed for separating dry fine coal particles from unwanted gangue particles. An experimental investigation of vibrational energy transmission, and the interaction between vibration and gas flow, was performed. The motivation for these experiments was a theoretical development of the principles involved in forming a dense-media vibrated fluidized bed (DMVFB). The mechanism of bubble breaking by vibration is discussed. A formula for calculating the critical vibration frequency at which bubbles can be efficiently broken and bubble formation restrained is proposed. The experimental results demonstrate that the density of a dense-media vibrated fluidized bed is uniform, with a maximum relative error of 1.68% under optimal technological and operating conditions. The < 6 mm fine coal was efficiently separated with a probable error E value of 0.07 t/m³. A lower limit of separation of 0.5 mm was achieved. The DMVFB separation efficiency is higher than wet jig with E value of 0.11 t/m³.     

EFFECT OF DRYING ON POWDER COATING EFFICIENCY AND AGGLOMERATION IN VIBRO-FLUIDIZED BED

Glass beads of 43 μm were coated in a vibro-fluidized bed by atomizing a fine silica powder together with polyvinyl alcohol aqueous solution. The coating efficiency and weight fraction of the agglomerated particles were measured under various experimental conditions, and their dependencies on the frequency and the direction of vibration were investigated. The coating efficiency and the degree of the agglomeration among core particles correlated well with an index R. The index R was introduced to evaluate quantitatively the drying conditions in a fluidized bed.

Application of vertical vibration on the fluidized bed lowered the coating efficiency somewhat, while it prevented agglomeration. From the experimental results it was confirmed that coating with high quality and high efficiency, where few agglomerates were produced and silica powder was utilized efficiently, was possible in a vibro-fluidized bed with adequate vibration frequency and orientation of the vibration vector.     

EFFECT OF DRYING ON POWDER COATING EFFICIENCY AND AGGLOMERATION IN VIBRO-FLUIDIZED BED

Glass beads of 43 μm were coated in a vibro-fluidized bed by atomizing a fine silica powder together with polyvinyl alcohol aqueous solution. The coating efficiency and weight fraction of the agglomerated particles were measured under various experimental conditions, and their dependencies on the frequency and the direction of vibration were investigated. The coating efficiency and the degree of the agglomeration among core particles correlated well with an index R. The index R was introduced to evaluate quantitatively the drying conditions in a fluidized bed.

Application of vertical vibration on the fluidized bed lowered the coating efficiency somewhat, while it prevented agglomeration. From the experimental results it was confirmed that coating with high quality and high efficiency, where few agglomerates were produced and silica powder was utilized efficiently, was possible in a vibro-fluidized bed with adequate vibration frequency and orientation of the vibration vector.     

Recovery of Platinum and Palladium from Spent Automobile Catalyst by Solvent-Impregnated Resins

ABSTRACT

Separation of platinum and palladium, using solvent-impregnated resin (SIR) impregnating di-hexylamine (DHA), di-n-octylamine (DOA), or di-hexyl sulfide (DHS), coated by polyvinyl alcohol crosslinked by glutaraldehyde, was investigated. Coating of the SIR successfully suppressed leakage of the extractant during adsorption. The coated SIR was applied to chromatographic recovery of the two metals and quantitative adsorption–elution was performed via the frontal analysis mode. The adsorption of Pt and Pd was achieved, while adsorption of the co-existing metals in the leaching solution was suppressed. Separation of Pt and Pd was achieved by employing sequential chromatography system together with the quantitative elution of Pt from DHA-SIR with the mixture of 0.5 mol/L thiourea and 0.5 mol/L HCl and that of Pd from DHS-SIR with the mixture of 0.1 mol/L thiourea and 0.5 mol/L HCl solution. Finally, elementary Pt was then obtained from the eluent of sequential chromatography system by simultaneous precipitation and reduction of Pt with sodium borohydride with 99.2% purity.     

Effect of Volume Fraction of Material on Separation by Density Difference in a Liquid‐Fluidized Bed of Inert Particles

A liquid‐fluidized bed was used to separate a pure material from a mixture. A quantity of relatively large sized material was immersed in an inert‐particle fluidized bed and the behavior of materials was examined for different liquid velocities. In particular, the volume fraction of the material was varied and its effect on the separation characteristics was examined. The material floats on the inert‐particle fluidized bed when the density of the material is lower than the apparent density of the bed, regardless of the volume fraction of the material. The apparent density of the bed can be adjusted by changing the liquid velocity. The materials in the upper portion of the bed affect the properties of the bed below them, i.e., the void fraction decreases and the apparent density increases in the inert‐particle suspension when materials are present in the upper portion of the bed. Therefore, the materials float on the bed although the apparent density of the inert‐particle suspension obtained from the case without material is less than the density of the material at a relatively high volume fraction of material. This phenomenon occurs more easily for lighter and smaller materials. This means that small inert particles and low liquid velocities are the optimum operating conditions for the separation.     

Modeling and Simulation of Continuous Rotating Annular Ion-Exchange Chromatography for Separation of Amino Acids

Abstract

Separation of an amino acid mixture using continuous rotating annular ion-exchange chromatography is numerically simulated by a newly constructed mathematical model. Dissociation reactions of amino acids and eluent buffer components, Nernst-Planck-type intraparticle ionic transport, and a nonlinear ion-exchange equilibrium based on ion-exchange selectivity are considered in the model. The simulated and the experimental results agree well under various operation conditions. The effects of rotation speed of the annular bed and the interstitial liquid velocity on separation are studied experimentally and theoretically.     

Prediction of the Behavior of a Liquid‐Fluidized Bed of Inert Particles Used for Separation by Density

A liquid‐fluidized bed of inert particles was used to separate a pure object from a mixture. One (binary solid‐liquid‐fluidized bed) or two (tertiary solid‐liquid‐fluidized bed) types of objects with relatively large‐sized particles were immersed in an inert‐particle bed, and the bed behavior was observed for different liquid velocities. The void fraction and apparent density of the inert‐particle suspension were predicted by considering the effect of the change in object position for different liquid velocities. The prediction method, which considers the change in the minimum fluidization velocity, accurately expressed the changes in the void fraction and the apparent density of the bed with the position of the objects in the bed. Using this method, the liquid velocity required to separate a certain kind of object from a mixture can be predicted.     

Separation of Metals by Rotating Film Pertraction

Separation of zinc (II) and iron (III), present in acidic HCl solutions, with tri‐n‐octylamine was studied applying a rotating film pertraction (RFP) technique. The effect of the main process parameters, disc rotation velocity and hydrochloric acid concentration in the feed, was investigated. It was found that tri‐n‐octylamine is a suitable extractant for zinc recovery or Zn/Fe separation from chloride media. High feed acidity favors more complete zinc recovery, while moderate HCl concentration ([HCl] = 0.25 mol/L) provides much better separation of the metals. The lower acidity (less than 0.10 mol/L) is recommended when pure zinc strip solution is aimed at.