Investigating the effects of particle shape on chromite entrainment at a platinum concentrator

In flotation, entrainment is undesirable as it results in the recovery of hydrophilic gangue particles which reduces the concentrate grade. For UG2 ore, a South African platinum group mineral (PGM) ore, entrainment is particularly problematic because it leads to the recovery of chromite in the final concentrate which can cause severe problems in the smelter. It is therefore important to understand all factors affecting entrainment. These factors include froth characteristics, as well as particle size distribution and density, which have been studied widely. Theoretically, they should also include shape, as shape affects drag coefficients of particles and thus hindered settling rates of particles within plateau borders. In this study, detailed mineral-specific shape characterisation with Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN) was used to assess the effect of particle shape on chromite entrainment during flotation of UG2 ore at a South African platinum concentrator. This plant-scale study suggests that shape does affect entrainment, with more rounded particles showing higher entrainment than angular, elongated particles.     

Optical analysis of particle size and chromite liberation from pulp samples of a UG2 ore regrinding circuit

Since the early seventies high chromite and low base metal sulphide (BMS) contents of the UG2 reef imposes technological challenges to mineral processors and extractive metallurgists. Forty years later, particle size distribution and size by size mineralogy are considered as key factors to the continuous improvement of the UG-2 ore metallurgy. With the successful development of ultra fine grinding technologies, a compromise has to be found between fine grinding to achieve platinum group minerals liberation and to avoid the overgrinding of gangue minerals, especially chromite gangue which is detrimental in smelting process. Indeed, fine chromite grains, despite of being naturally hydrophobic mineral, can be recovered in flotation concentrate by entrainment. In addition, overgrinding also increase liberation of naturally floatable gangue (talc) which contaminate the concentrate and need to be controlled during flotation.In this paper, innovative techniques of single particle image analysis from both dry and wet samples have been tentatively used to assess the chromite particle size distribution and the chromite grade of samples taken from a secondary milling circuit. Preliminary results demonstrate excellent potential for online particle imaging making use of both the particle geometry (size, shape) and the optical properties (translucency).     

研磨介质形状对铁矿石磨矿动力学研究

以由粗到细的四种单粒级铁矿石为研究对象,基于磨矿动力学原理,解析了三种研磨介质(钢球、钢锻以及立方体)对铁矿石颗粒的破碎行为,探究了磨矿动力学参数k和m,获得了矿石在三种研磨介质下的比破碎速率。研究表明:随着单粒级铁矿石给料尺寸由小到大,矿石在三种研磨介质下的比破碎速率先增加后减小,其中,采用钢球为研磨介质时,矿石比破碎速率最大,钢锻次之,立方体的最小;不同给料尺寸下,采用钢球为研磨介质时的k和m始终最大,立方体的始终最小。     

The effect of breakage method on the shape properties of an iron-oxide hosted copper–gold ore

Using a mineral liberation analyser (MLA), the shape properties of an iron-oxide hosted copper–gold ore following comminution in either a hammer mill or a piston–die compression unit were examined. It was found that particle angularity distributions were able to be fitted to the beta distribution, providing a convenient way to quantify changes in particle shape properties as a function of the breakage method employed. Particles discharged from the hammer mill were less angular than particles discharged from the piston–die compression unit. This was attributed to attrition breakage mechanisms, whereby topographical features are chipped off parent particle surfaces. The results suggest that the quantification of shape properties is a convenient method for obtaining insight into the nature of breakage events that take place inside comminution devices.     

某钾盐矿层形态变化原因和应对措施探讨

某钾盐矿床为海源陆相沉积成因矿床,其重要的找矿标志为"盐背斜"。也正因为盐背斜的存在,使整个矿床在形态上表现为面积大、矿层薄、起伏大的特点。随着地质工作的深入开展,矿体形态发生了较大的变化,并伴随着资源储量的较大变化,这给矿山的开发和规划造成了很大的不确定性。因此,提高矿体的可靠性,为井巷布设、矿山开发和规划提供准确的地质资料就显得尤为重要。通过对比历次地质工作成果,分析原因并提出应对措施。     

矿石形状对浸堆结构及渗流场影响机制

为了研究筑堆矿石形状对堆内结构和渗流速度场分布的影响,选取了相同级配下的球团制粒矿石与普通原矿石进行柱浸实验。利用核磁共振成像(MRI)技术非接触地获取内部饱和结构,通过图像处理与统计研究了矿石形状与孔隙分布的关系,并利用Navier-Stokes方程模拟了相同压力和入渗速度下矿石形状对渗流速度场的与优势流分布影响。结果表明,饱和状态下的内部孔隙并不都服从正态分布,制粒矿石间孔隙分布更为均衡,服从正态分布,μ=2.0mm,原矿石间孔隙分布不服从正太分布,在8.00～11.00mm间缺失,最大当量直径为11.39mm;制粒矿石间速度场分布更加均匀,孔隙间无明显优势流,原矿石间速度场分布不均衡,存在贯穿结构的优势流和较大浸出盲区,出口边界表现为流场叠加状态;提出矿石形状均匀系数K可以有效描述矿石形状对内部孔隙和渗流的影响机制,K值小,孔隙分布均衡,渗流速度场分布均衡;K值大,容易产生大孔隙,连通成为优势流的通道,致使流场分布不均衡。     

磨机系统的计算方法

介绍了磨机系统的整体计算分析方法,比较了磨机整体计算和传统计算优、缺点.     

纳米复合瓷球在钨矿石细磨中磨矿特性研究

以湖南某钨矿石为对象,研究纳米复合瓷球作为磨矿介质在钨矿石细磨中的磨矿特性。研究表明,纳米复合瓷球作为细磨介质可以对钨矿石进行有效破碎,实验室细磨试验可以获得新生—74μm粒级产率21.08%、新生—23μm粒级产率7.59%的磨矿产品,过粉碎现象较钢锻显著改善;在介质充填率相同情况下,纳米复合瓷球比钢锻节能69.92%;纳米复合瓷球不仅磨矿产品粒度特性更均匀且不会引入铁质污染,相同细度下,纳米复合瓷球磨矿产品浮选开路试验钨回收率比钢锻高10个百分点左右,尾矿钨损失降低50%。首次将纳米复合瓷球应用于细磨作业,并获得良好效果,对以后研究具有借鉴意义。     

Use of fluorinated alcohols to intensify copper-nickel ore grinding

The experimental data are reported on intensification of the copper-nickel grinding by feeding fluorinated saturated mono-atomic alcohols of a general formula H - (CF₂CF₂) _n - CH₂ - OH into a mill. The feeding of this reagent into a mill at the rate of 25–100 g/t of feed provides better exposure of aggregates in the ore preparation circuit thus intensifying the subsequent ore flotation. The increment of copper and nickel recovery into a concentrate amounts to more than 4%. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 95–100, July–August, 2008.     

基于UG的直齿圆锥齿轮三维建模研究

对圆锥齿轮齿形进行了理论分析,对建模中齿形的处理方法进行了论述,并对直齿圆锥齿轮齿廓曲线的绘制方法和直齿圆锥齿轮在UG中的三维建模方法进行了详细介绍,最终给出了直齿圆锥齿轮的三维模型。     

藤铁矿区Ⅱ号矿体地质特征及其成矿规律

通过对广东怀集藤铁铁矿区Ⅱ号矿体地质特征的描述,论述了矽卡岩型铁矿与燕山期花岗岩的关系;分析认为赋矿层位为泥盆纪大理岩与花岗岩接触带,指出了矽卡岩型铁矿的找矿方向为燕山期花岗岩环抱的泥盆纪大理岩舌状残留体的前部及根部.     

锡石多金属硫化矿微波助磨试验研究

本文以广西某选矿厂锡石多金属硫化矿矿石为原料,研究了微波预处理对矿石磨矿产物粒度组成、磨矿动力学、破碎速率及磨机生产能力的影响。结果表明,微波预处理后,矿石在不同磨矿时间下的磨矿产物粒度均变细,-0.074mm粒级含量提高了4.41%~12.90%;微波预处理前后该矿石磨矿均符合一级磨矿动力学模型;微波预处理使矿石的破碎速率(S₁)值提高近57%,且磨机的生产能力得到了明显提升。因此,微波预处理可以降低矿石的强度,强化矿石的磨矿过程,是一种有效的降低磨矿能耗、提高磨矿效率的方法。     

浅谈磨浮自动化工程在钼矿的应用

介绍了赤峰某钼矿的磨浮自动化控制工程项目,以磨机恒定给矿自动化系统为例,介绍了调试过程中遇到的问题及解决办法。     

齐选厂与东烧厂二次磨矿介质消耗研究

提出了按矿石性质、粒度要求、工艺设备不同进行磨矿介质消耗研究的新方法.在对齐大山和东鞍山铁矿石磨矿功指数及可磨度进行研究的基础上,计算分析了齐大山选矿厂与东鞍山烧结厂二次磨矿介质理论和实际的消耗及对比情况,指出相关磨矿作业应加强降低磨矿介质消耗的研究工作.     

Semi-automated iron ore characterisation based on optical microscope analysis: Quartz/resin classification

The present study focused on overcoming the primary problem faced by any quantitative mineralogical study involving iron ore characterisation using a reflected light optical microscope; distinguishing the quartz mineral from the epoxy resin in digital images taken from mounted polished sections. Difficulties arise in this case because both phases reflect in the same colour intensity range. To overcome this problem, a digital image analysis system denominated Opt_-Lib was developed. In order to evaluate the system responsivity, a characterisation study and modal and liberation analyses were performed using typical Brazilian iron ore containing quartz and the main iron oxide/hydroxide minerals: magnetite, hematite, and goethite. For the system performance evaluation, these results were compared with those generated by the scanning electron microscopy (SEM)-based Mineral Liberation Analyzer for the same sample. The results show that the main advantage of the Opt_-Lib system over the SEM-based system is that it facilitates differentiation, classification, and quantification of not only the quartz mineral, but also the iron oxide/hydroxide minerals within the sample, thus providing a more precise qualitative response.     

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。     

Synthesis of 2-ethyl-2-hexenal oxime and its flotation performance for copper ore

A novel collector 2-ethyl-2-hexenal oxime was synthesized from 2-ethyl-2-hexenal and hydroxylamine hydrochloride. The yield of oxime was 78.05% under the optimum experimental conditions. The oxime was characterized by elemental analysis, infrared spectrum, mass spectrum, ¹H NMR and ¹³C NMR spectroscopy. The results of ultraviolet spectrum showed that the oxime exhibited stronger reaction affinity with Cu²⁺ than with Ni²⁺ or Fe³⁺, etc. Infrared spectroscopic analysis implicated that the oxime bound to Cu²⁺ through both the CC and CN groups. Microflotation tests of pure malachite mineral and chalcopyrite mineral indicated that the recovery of chalcopyrite was 91.16% under the flotation condition of rougher pH 10 and collector concentration of 200 mg/L, and the recovery of malachite reached 90.56% under the flotation condition of rougher pH 11.5 and collector concentration of 250 mg/L. The results of flotation tests of sulfide–oxide copper from Dexing copper mine showed that 2-ethyl-2-hexenal oxime achieved an excellent mean concentration containing 4.52% Cu with 79.54% Cu recovery, and the Cu average recovery increased by 2.35% compared to that of butyl xanthate.     

MCGS在选矿厂磨矿分级自动化中的应用

基于攀枝花选矿厂磨矿分级过程工艺特点和要求,介绍了MCGS(监控组态软件)在磨矿分级自动化中的应用,提出了针对磨矿分级过程的智能控制技术。     

酒钢两种粉矿矿石性质及可选性对比试验研究

酒钢镜铁山铁矿分为桦树沟和黑沟两大矿区,前者为井下矿,后者为露天矿,两者的矿物组成、结构构造及选矿参数均有较大差异,但却进入相同的工艺,采用相同的参数进行选别,造成生产技术指标不是最佳。通过对两种粉矿的矿石性质及可选性进行对比研究,查明其差异,并确定各自适宜的磨矿、选别等工艺参数,为进一步改善精矿质量、提高资源利用率提供依据。     

泥矿和高品位精矿搅拌浸出工艺研究

对堆浸前矿石的破碎分级中的泥矿和高品位精矿进行了搅拌浸出工艺的实验室试验研究和现场验证试验。泥矿酸法搅拌浸出铀浸出率达到96%以上。高品位矿石碳酸盐含量高,酸法浸出铀浸出率可达99%以上,但是酸耗高;而碱法浸出高品位矿石时,在常温条件下浸出率不到70%,提高浸出温度可显著提高浸出率。使用压滤机进行固液分离是可行的,其矿石处理能力可达到155 kg/(m2.d),洗涤效率达99%以上。