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.     

Total recovery of gold,palladium, and platinum using lignophenol derivative

A tertiary amine type adsorption gel was prepared by the immobilization of dimethylamine onto crosslinked lignophenol (CLP) matrix. This novel product was studied for its adsorption behavior for Au(III), Pd(II), Pt(IV), Cu(II), Zn(II), Ni(II), and Fe(III) in 0.5–6 M hydrochloric acid medium. From our previous study, crosslinked lignophenol (CLP) is known to hold solo selectivity for Au(III). After modification to dimethylamine type adsorbent (DMA-CLP), an extended selectivity of Au(III), Pd(II), and Pt(IV) was observed. The maximum loading capacity for these three metal ions was evaluated by isotherm study. For Au(III) an impressive value of 7.2 mol/kg of DMA-CLP was observed. The feasibility of recovery of precious metals from a mixture containing several other metal ions was studied in batch mode by using both model solution and actual industrial solution obtained after aqua regia leaching of metal components in obsolate e-devices. In addition, a number of adsorption–elution cycles were produced so as to know the feasibility of multiple uses.     

Surface chemistry features in the flotation of KCl

Despite the successful industrial practice to recover KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the flotation behavior of KCl and NaCl using different collectors and captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of collector concentration and collector structure is considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt surface, with finite contact angle values of between 30° and 60°. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collector adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs.     

Review of hydrodynamics and gas dispersion in flotation cells on South African platinum concentrators

Hydrodynamic and gas dispersion parameters, obtained from industrial flotation cells on South African Platinum concentrators, are reviewed in this paper. Hydrodynamic results show that power intensities are slightly higher than those typically observed in industrial flotation cells while impeller tip speeds and Froude numbers are within the range found in industrial cells. Gas dispersion results show that air flow rates, air flow numbers and air flow velocities vary significantly from cell to cell but are within the range typically found in industrial flotation cells. Gas dispersion results also show reasonably broad variations in bubble size, gas holdup and superficial gas velocity, although bubble surface area fluxes are shown to lie within a fairly narrow range of 50–70/s.     

Experimental-analytical methods of the investigating the effect of complexing reagents on platinum flotation

The paper considers the studies into the hydrophobic properties of platinum and platinum arsenide, sperrylite, in the solution with added complexing reagents by using the method of measuring the force of the air bubble abstraction from the mineral surface. The effect of these complexing reagents on the chemical properties of sperrylite and pyrrhotine is analyzed. A new-developed procedure for treatment of pyrrhotine by chloroplatinic acid is presented, and the comparative flotation of natural pyrrhotine and platinum-pretreated pyrrhotine with the complexing reagents is described. The collecting properties of diisobutyl dithiophosphinate for platinum are determined, and the use of this reagent as an additional collector for platinum-group metals is confirmed in the course of the experimental flotation of platinum-bearing copper-nickel ore samples. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 68–75, May–June, 2008.     

Development of a flotation model incorporating liberation characteristics

A liberation/flotation model has been developed to evaluate flotation performance, in which the grade distribution of composite particles is incorporated explicitly. The grade distribution of particles at a given size fraction was calculated using a predictive liberation model developed by the authors. Flotation behaviour of these particles in narrow size fractions were evaluated using batch flotation tests. The recovery of particles in narrow size/grade classes at various flotation times under a given flotation environment were obtained from SEM images of mounted specimens of feed, concentrate and tailings samples using image analysis techniques.By describing the size, grade and recovery data of particles in narrow size/grade classes by separate matrices, a transformation matrix technique has been developed that can predict the flotation performance of a composite sample of an ore comprising various size classes. It has been shown that the predicted results agree well with the observed results.This liberation/flotation model has wide applications in geometallurgical testing and design, where the downstream flotation performance is to be determined with limited availability of ore samples and their liberation characteristics. It also alleviates the deficiencies involved with flotation models that assumes first order behaviour.     

Fundamental electrochemical and Raman spectroscopic investigations of the flotation behaviour of PtAs2

Platinum arsenide minerals are important platinum carriers in altered platinum reserves such as the Great Dyke of Zimbabwe and the Platreef (in the Bushveld Complex of South Africa). Industrial mineralogical investigations suggest these minerals to be poorly recovered during froth flotation and are believed to be slow floating. In this work, electrochemical investigations, electrochemical contact angle measurements and Raman spectroscopy have been employed to investigate the interaction of ethyl xanthate with synthetic PtAs₂. The electrochemical investigations suggest a strong interaction of the xanthate with the mineral at potentials higher than the reversible potential of the xanthate–dixanthogen couple. Raman spectroscopy has confirmed the presence of dixanthogen on the mineral surface when the surfaces are anodically polarized. Contact angle investigations indicated the surface to be hydrophobic; possible mechanisms of the slow floating behaviour are discussed.     

铅锌矿产资源特征及浮选工艺研究现状

在分析铅锌矿产资源储量和开发利用现状的基础上,重点阐述了我国铅锌矿产资源特征及其开发利用过程中所面临的难题;探讨了优先浮选、混合浮选、等可浮选、异步浮选和分支串流浮选等铅锌选矿工艺的优缺点,论述了选矿工艺技术的创新与发展方向。     

Microfluidic solvent extraction of platinum and palladium from a chloride leach solution using Alamine 336

Microfluidic solvent extraction (μSX) of platinum and palladium from chloride leach solution using Alamine 336 had been conducted. The leach solution was produced by leaching of spent automotive catalysts. A microfluidic Y–Y channel embedded in a Pyrex™ microchip was used as the extraction system. Platinum and palladium extractions (>99%) occurred at μSX contact time as fast as 1 s with subsequent marginal extraction efficiency increases for longer contact times with comparable extraction performance to that of bulk SX. Findings from this preliminary study are useful in initiating a new metallurgical technique in the field of recovering precious (high-value) metals present in low concentrations which are otherwise not technically amenable (or economically viable) to extraction using current conventional methods.     

Evaluation of alternative reagent schemes for the flotation of platinum group minerals from various ores

In the past several years, research work has been carried out on a number of different ores containing platinum group elements (PGE), with the objective of developing alternative reagent schemes that would improve PGM recovery and concentrate grade in the operating plants.It has been demonstrated that the floatability of PGE-bearing minerals largely depends on the type of deposit and how the deposit was formed. The uniqueness of PGE deposits and their formation dictates the development of the treatment process and, in particular, the reagent schemes for different ore types.In this study, a number of different new reagents, including collectors, depressants and modifiers, were identified as highly effective for the treatment of different ores containing PGE minerals. Results from bench scale research work using new reagents are presented in this paper. The type of ores and the effect on flotation are discussed in detail.     

蓝晶石矿物的晶体结构与浮选行为研究

本文选取蓝晶石纯矿物为研究对象,研究其晶体结构与表面性质之间的关系及其对浮选行为的影响,从而为有效分选蓝晶石矿物提供理论指导。结果表明:金属离子Mn+-Xn-键的强弱顺序为Si-OAl-O,蓝晶石矿物解离后表面暴露大量的化合价和配位价不饱和的Al 3+离子,在水溶液中零电点相对较高,表明在强酸性环境中采用十二烷基磺酸钠作捕收剂浮选效果极好,在中强碱性环境中则采用油酸钠作捕收剂浮选时可浮性较好。     

浮选单元搅拌类设备特性评析

作为浮选单元的主要搅拌类设备,浮选机与搅拌槽在作用机理上存在相似性,即均以搅拌机构为主体。但这2种设备隶属于不同的作业单元,各自的作用职责不同,相应作用机理特性也不同。从设备结构、搅拌机理作用下的流场特性以及搅拌过程作用条件三方面出发,对浮选机与搅拌槽的特性进行了分析与总结,实现了对相应作用特点及机能的明确界定,为各自进一步的优化设计及作用强化措施体系构建奠定了基础。同时指出,浮选机与搅拌槽应在作用效果上充分发挥其作用,共同组成实现工艺流程高效性的技术要求与保障。     

浮选体系中气泡运动特性研究进展

在浮选体系中,气泡的运动特性直接影响着矿物浮选的选别效果,因此,研究气泡的运动特性,对于优化浮选工艺与改善浮选效果有着重要意义。本文首先简述了浮选中常见的气泡生成方式,主要有机械搅拌发泡、气泡发生器发泡、电解发泡及超声波发泡四种方式;气泡参数中介绍了气泡形态特征参数、运动特征参数和分布特征参数的含义和计算公式;然后重点阐述了浮选中起泡剂、捕收剂、抑制剂、浮选机叶轮参数、浮选柱气泡发生器及充气量对气泡参数的影响;归纳了纳米气泡在微细粒矿物浮选中的应用;最后指出,完善气泡测量方法、侧重于气泡在实际浮选环境中的运动特性研究以及研发新型纳米气泡生成设备将是未来的发展方向。     

XJM-S28型浮选机技术特点及应用

为了适应选煤厂大型化发展对大型浮选设备的迫切需求,采用模拟放大方法,研制出单槽容积为28 m3的煤用机械搅拌式浮选机——XJM-S28型浮选机。XJM-S28型浮选机在山西焦煤集团、河北开滦集团、华晋焦煤集团等煤炭生产企业的应用实践表明,该机对煤泥可浮性适应能力强,分选指标稳定,工艺灵活,可较好地满足大中型选煤厂浮选生产需求。     

黄铜矿和方铅矿的电化学特性及浮选行为研究进展

黄铜矿和方铅矿作为铜铅金属最主要的冶炼矿物,浮选分离问题一直是行业内关注的重点。本文基于黄铜矿和方铅矿的半导体特性,从电化学角度分析了矿物表面的氧化规律、矿物学因素对浮选行为的影响及各种有机抑制剂在铜铅浮选分离过程中的作用机理。黄铜矿和方铅矿在矿物加工过程中均会产生不同程度的氧化,且氧化产物类型决定矿物的表面性质;矿物成矿过程中产生的流体包裹体及各种类型的晶格缺陷会影响矿物的浮选行为,电化学调控和有机抑制剂的研究和应用可以改变矿物固有的浮选行为,实现黄铜矿和方铅矿的浮选分离。分析认为,应注重矿浆电位对半导体矿物浮选行为的影响,将浮选电化学和浮选溶液化学等理论相结合是研究复杂矿浆体系的有效方法。     

一种新型浮选柱发泡器生成气泡特性研究

在自行设计的浮选柱模拟系统中,对一种新型浮选柱微泡-逆流接触式浮选柱气泡发生器的发泡特性进行系统研究;以发泡器产生的气泡为研究对象,通过高速摄像记录仪获取气泡图像,采用图像处理软件对气泡直径及速度进行提取、统计,考察气泡发生器在不同充气条件下气泡密度及气泡尺寸分布特征,探索生成气泡的尺寸和速度之间的对应关系。研究结果表明,随充气量增大,气泡平均直径增大,气泡尺寸分布由变宽,微气泡数量减少;在充气量Q=4 L/min时,气泡尺寸分布比较均匀且产生充足的微气泡;气泡上升速度主要取决于充气量和气泡尺寸,通过试验数据分析,提出了该浮选柱气泡发生器生成气泡上升速度与尺寸之间的指数关系式。