Collection zone kinetic model for industrial flotation columns

The collection zone recovery of a flotation column was modeled using a rectangular distribution function for the kinetic rate constant and a tank in series model with different vessel sizes for the residence time distribution. It was demonstrated that an analytical expression can be obtained and that data from large industrial columns fits well, keeping the parsimony principle by using a simple and practical solution. An example for the estimation of the maximum kinetic rate constant, useful for scale-up purposes, is shown using data from industrial flotation columns.     

An experimental study of the recovery of hydrophilic silica fines in column flotation

This paper presents results of tests performed to investigate the effect of gas rate (1.2–2.5 cm/s), hydrophilic fines content (5–20% w/w silica) and froth depth (10–30 cm) on fines recovery in a laboratory-scale flotation column operating without wash-water addition and absence of floatable particles. A model was developed based on the entrainment coefficients presented by [Trahar, W.J., 1981. A rational interpretation of the role of particle size in flotation. International Journal of Mineral Processing 8, 289–327], which describes the mass contribution of the different size classes to the solids recovered in the concentrate. The entrainment model of [Zheng, X., Johnson, N.W., Franzidis, J.P., 2006. Modelling of entrainment in industrial flotation cells: water recovery and degree of entrainment. Minerals Engineering 19, 1191–1203] was also tested. The results show both models described well the dependence of the mass flow rate of hydrophilic solids in the concentrate.     

Arsenopyrite enrichment by column flotation

Arsenic-rich, gold-bearing pyrite concentrates may be further enriched in arsenic to assist subsequent Au beneficiation. Among several amines tested in refloating a local Chalkidiki pyrite concentrate, 2-coco 2-methyl ammonium chloride proved successful by raising the grade from 9% to 22%, although total solids recovery was low. The use of a froth-stabilizing frother was also benefecial to the process. Optimum hydrohynamic conditions were: intermediate pulp flowrate, low wash water and gas flowrate; the latter abated the mixing/dispersion process in the collection zone.     

浮选柱研究和应用进展

简要回顾了浮选柱发展的历史，对其近几十年的研究和应用进展进行了较全面的论述，并对其今后的发展趋势进行了预测。     

Recovery of coal fines using column flotation

Tests carried out on 100mm dia × 2300mm high flotation column using coal fines from the coking coal washeries at Sudamdih, Patherdih, Kathara and Moonidih (India) have shown that the performance of the column is superior to that of the conventional cells with respect to the grade and recovery of the product. The column is found to operate efficiently both on coarse and fine fractions in the feed. The reasons for the superior performance of the flotation column have been analysed.     

The mixing characteristics of solid and liquid phases in a flotation column

This paper presents results obtained in determining the residence time distribution (RTD) characteristics of the solid and liquid phases in a laboratory column and two industrial columns using radioactively labelled solid and liquid tracers. The dispersion model is shown to be superior to other models in describing the RTD in columns with diameter between 10cm and 150cm. Smaller diameter columns can be modelled using either the dispersion model or the tanks-in-series model and larger columns can be modelled using the latter model. Feed and gangue material produce similar tailings age distribution curves. The solid dispersion coefficient is larger than the liquid dispersion coefficient. The solid dispersion coefficient increases with increasing particle size in the laboratory column but remains constant with increasing particle size in the large columns. A modified correlation is proposed to predict the solid dispersion coefficient in large columns.     

Column flotation circuits in Chilean copper concentrators

This paper reviews the column flotation practice in the largest Chilean copper-moly concentrators where this process unit has been increasingly chosen to replace multi stage cleaning circuits in new and existing operations. Process flowsheets incorporating columns are presented for selected concentrators. Procedures for scaling up, and process control are also illustrated.     

宽粒级煤浮选机流场数值模拟研究

将流态化机理与宽粒级煤浮选过程相结合,在一个浮选设备中实现细粒常规浮选与粗粒流态化浮选所需的不同流体力学环境,自行设计了一种新型宽粒级煤浮选机,并采用FLUENT 6.3.26软件进行数值模拟研究,从速度和湍流度两个方面对浮选机内流场进行分析。结果表明：在浮选机内增加格栅板后,可将浮选机内流场分为低速、弱湍流和高速、强湍流两个区域,从而可为粗、细颗粒浮选创造各自所需的流体力学条件;通过对叶轮圆周线速度比值与合速度比值和湍流强度比值变化规律的分析,找出浮选机模拟放大的运动相似准则。     

Temperature sensitive polymers as efficient and selective flotation collectors

This study investigates both the efficacy and selectivity temperature responsive of poly(N-isopropylacrylamide) PNIPAM as a flotation collector. The results of this study showed that charged poly(N-isopropylacrylamide) polymers selectively increased both the probability particle/bubble attachment as well as the floatability of coarse alumina and quartz particles respectively. These results provide a basis for considering PNIPAM as both an effective and selective collector in a flotation system. Coupled with previous studies that demonstrate the efficacy of PNIPAM as a flocculant in mineral suspensions, these results clearly demonstrate the potential use of PNIPAM as a dual function reagent which acts as both selective flotation collector and flocculant in the flotation of ultrafine particles.     

射流浮选柱的两相流数值模拟

建立了浮选柱内部流动的两相流流动方程,给出了方程中各未知变量的具体算法.对Microcel浮选柱进行了两相流数值模拟,得出不同条件下该浮选柱内部速度场的分布,并与实测速度值进行了比较和分析.研究结果表明,入料、尾矿口的布置对浮选柱内部流场有重要影响,浮选柱内部流动稳定性可以用k值评定.     

Column flotation simulation and control: An overview

Even after having been used for several years in mineral processing plants, the full potential of the column flotation process is still not fully exploited. There is obviously more than one reason explaining this, but one important contributing factor is certainly the under usage of available control capabilities. Researchers and practitioners have been interested in column flotation simulation and control for more than two decades. This paper provides an overview of the literature focused on these specific fields of research. It also discusses some future investigative issues and how the current industry may benefit from past developments.     

Molecular modelling of reagents for flotation processes

It has long been recognized that the selectivity of froth flotation processes is highly influenced by the specificity of interactions between minerals and reagents that are used to control the hydrophobic/hydrophilic character of the mineral/water interfaces. We have modelled mineral surfaces (hydroxy-apatite, calcite) and molecules of two polysaccharides (starch, ethyl-cellulose) which are candidates as depressing agents for calcite. A special parameter named “Total Fitting Number” (Ft) was developed to assess the steric compatibility between the structure of both minerals and polysaccharide species. The calculation of Ft was based on measurements of OH-OH distances that exist at reagent molecular structures versus Ca---Ca distances that exist along the most common crystallographic orientations (hkl) exhibited by mineral particles.Higher values of Ft were found for the interaction calcite/starch than calcite/ethyl-cellulose. This finding suggests that starch is a more effective depressant for calcite than ethyl-cellulose. However, low values of Ft were found for the interaction apatite/starch and apatite/ethyl-cellulose. This fact means that both substances are unlikely to act as depressants for apatite. Microflotation response of apatite and calcite with sodium oleate (pH = 10.2) in the presence of both polysaccharides corroborates the model.     

旋流-静态微泡浮选柱的应用及研究进展

简要介绍了旋流-静态微泡浮选柱的结构、浮选原理及优缺点,针对该设备的研究进展,从理论研究、计算机模拟及自动化、结构优化研究、机柱联合四个方面进行综述,同时分别总结了该设备在金属矿选矿、选煤及非金属矿选矿中的应用情况。指出该设备未来的几个研究方向,同时指出该设备将更广泛地应用于选矿业。      

Estimation of platinum flotation grades from froth image data

Features extracted online from froth images on flotation plants are potentially useful to the development of advanced control for flotation systems, provided that these features can be related to the key indicator variables of the plant, such as valuable metal loadings and recovery. Although such relationships have been established in a number of base metal plants in industry, this is not the case in the platinum industry. In this paper, estimation of flotation grades and recoveries from froth image data is therefore considered based on laboratory and industrial plant data. It is shown that grades and recoveries can be reliably estimated from a number of different features by use of linear and nonlinear models. This includes simple colour information that on the industrial plant showed a strong correlation with grade measurement.     

Supervisory control of flotation columns using multi-objective optimization

This work describes a method for supervisory control of flotation columns based on predictive trajectory generation of setpoints to be applied to the local controllers of the process. The system maximizes the profit while keeping quality constraints and engineering indices. It represents an advance over predictive supervisors using a single evaluation function or those that reduce a multi-objective problem to a single-objective one by means a weighted sum. The procedure is founded on multi-objective optimization using non-dominated genetic algorithms, and a new classification criterion of the Pareto optimal set. The system has been tested by simulation against usual perturbations affecting the flotation process and exhibits good performance, provided that the model properly represents the system operation.     

浮选尾煤再选试验研究

以钱家营选煤厂浮选尾煤为对象,进行再选试验研究。对煤样进行粒度分析,发现高灰细泥含量很高,决定采用反浮选预先脱泥,并探索了药剂用量对反浮选效果的影响;脱泥后的产品进行磨矿再选,工艺流程为:"反浮选─磨矿─再选"流程,最终得到了灰分为13.96%,产率为25.96%的精煤,采用该流程处理浮选尾煤可提高选煤厂经济效益。     

浮选回路配置的浮选动力学探讨

本文从浮选动力学的角度,对选矿厂浮选回路配置进行了探讨.认为采用目前性能先进的短柱型浮选机,单排配置槽数少,有利于矿物浮选性能的改善.     

XJM-S系列浮选机的研发及展望

浮选是目前细粒煤泥处理最有效、应用最广泛的方法.XJM-S系列浮选机在我国煤泥浮选设备中占有率最高,达70％以上.为使选煤同仁全面了解XJM-S系列浮选机技术特色、应用及发展,简述了 XJM-S系列浮选机的工作原理、设计思路及其结构特点,回顾了该设备的研发历程,介绍了指导大型设备参数设计的放大准则,以及采用流场数值模拟...     

自吸气浮选机隔板叶轮研究

叶轮的结构型式和运行参数决定了浮选机的整体性能,结合理论分析及工程经验设计了一种功能分区的隔板叶轮。利用CFD仿真方法和试验方法对隔板叶轮的整体性能进行了测试,在仿真条件下分析了槽体内的流场结构、气液分散、功耗、循环量和吸气量等,并采用试验方法进一步对隔板叶轮的性能进行了研究,结果过表明,隔板叶轮循环量增加,吸气量略微减小,功耗略微增加,槽体下方搅拌能力增强,隔板叶轮整体性能较标准叶轮相当。