基于LabVIEW的浮选泡沫图像处理及灰分预测研究

以Lab VIEW为平台,对山东某选煤厂的煤泥浮选泡沫图像进行处理,并对泡沫图像的特征参数进行采集,而后利用这些参数基于BP神经网络模型对浮选泡沫产品的灰分进行了预测和分析,取得了较好的预测效果。     

煤泥浮选泡沫图像灰度直方图及其统计纹理特征研究

针对煤泥浮选泡沫图像灰度直方图特征问题，进行了实验室浮选柱试验，采集了50组煤泥浮选泡沫图像，分析了泡沫图像及其直方图的类别及形态，提取了浮选泡沫图像直方图统计纹理特征参数，研究了泡沫直方图统计纹理特征参数随浮选时间的变化关系。研究表明，统计纹理特征参数-方差能够表征浮选泡沫图像直方图特征，并与特定的泡沫状态相关，可为煤泥浮选视觉监控系统提供泡沫状态信息。     

浮选指标与浮选泡沫数字图像关系研究

在实验室采集了大量黄铜矿浮选的泡沫图像,并对浮选泡沫图像进行了预处理;采用数字图像分析技术分析了泡沫图像及其灰度直方图,提取了浮选泡沫图像灰度直方图的统计纹理特征参数;采用径向基神经网络建立了黄铜矿浮选指标与泡沫灰度直方图统计纹理特征参数的关系模型。仿真实验证明,所建立的模型有较高的精度。     

高砷多金属硫化矿浮选降砷途径

系统阐述了瑶岗仙钨矿高砷多金属硫化矿所进行的浮选降砷试验,作了三个方案。第一方案用活性炭脱药,以石灰作pH调整剂。乙硫氮和丁黄药作捕收剂,松醇油作起泡剂,石灰和亚硫酸钠作组合抑制剂。经一次粗选,一次扫选和三次精选,精选工尾矿和扫选泡沫产品再选,泡沫产品与其它精选尾矿集中返回粗选。槽内产品返回扫选的工艺流程;第二方案用胺醇黄药取代第一方案的乙硫氮;第三方案用YFA取代第一方案的亚硫酸钠。三个方案均取得了满意的结果。     

BFIPS―Ⅱ泡沫图像分析仪软件系统的设计与实现

基于BFIPS-Ⅱ泡沫图像分析仪的开发与应用,介绍了泡沫图像分析仪软件系统的系统架构、系统平台、系统功能,以及在系统平台下应用实现的关键技术。系统平台可以实时处理未压缩的泡沫图像视频流,计算泡沫图像的特征参数,建立特征参数与精矿品位的数学模型。     

煤泥浮选泡沫的图像处理

介绍了煤泥浮选泡沫图像灰度处理的几种方法，对泡沫图像的个体特征作了分析，并为煤泥浮选泡沫图像的识别提供算法依据。     

复杂混合浮选泡沫图像分割方法研究

针对浮选泡沫图像难以直接识别的问题,提出了一种基于形态学的分水岭改进算法,利用CLAHE、最小最大值滤波对泡沫图像进行预处理,采用形态学方法进行图像重建,最后利用分水岭算法对重建后的图像进行分割。仿真结果表明,该算法可有效地对复杂混合泡沫图像进行分割。     

煤泥浮选泡沫图像灰度行程及其统计纹理特征

针对煤泥浮选泡沫灰度图像统计纹理特征问题，通过实验室浮选柱试验，采集了大量的煤泥浮选泡沫图像，分析了泡沫图像的类别及特征，提出了描述浮选泡沫纹理特征的灰度行程矩阵提取算法，并进一步提取灰度行程矩阵的行程因子特征参数来描述浮选泡沫的视觉纹理特征，分析了各特征参数随浮选时间的变化关系.研究表明，泡沫灰度行程因子特征参数能够表征浮选泡沫图像纹理特征，并与特定的泡沫状态相关，可为煤泥浮选视觉监控系统提供泡沫状态信息.     

煤泥浮选泡沫图像滤波方法的选取

煤泥浮选泡沫图像的去噪对于后续的图像准确处理与识别有着不可忽视的影响。鉴于各传统去噪方法在去噪和保留高频信息之间的矛盾,文章将煤泥浮选泡沫图像常规滤波方法中的中值滤波和小波滤波与基于面积重构开闭滤波与交替顺序滤波结合形态学滤波进行了比较,通过对煤泥浮选泡沫去噪后的图像进行分析,得出形态学滤波方法可最大限度地压制噪声的影响,同时使图像的原貌得到了保护,取得了良好的图像降噪效果,对煤泥浮选泡沫图像而言是一种较好的图像滤波方法。     

白云鄂博稀土矿浮选泡沫图像颜色特征与品位相关性研究

在稀土矿物实际浮选中,泡沫颜色特征与稀土品位关系密切。针对白云鄂博稀土矿浮选过程中浮选槽中含气率高、气泡重叠、变形,以及不断发生气泡兼并与破裂的情况,设计建立图像采集系统,并针对LED光源特点,设定照射光源最佳角度,进行图像采集。对采集图像进行进一步颜色特征提取,对泡沫图像颜色与品位之间的相关性进行分析研究。根据浮选过程中浮选泡沫表征颜色与品位的相关性,结合计算机图像处理技术,使用Matlab数学分析软件,对泡沫图像进行预处理并且进一步对泡沫图像进行边缘提取,对泡沫色彩进行色彩效果增强处理,将颜色分类量化,并进行色彩分类统计。通过对泡沫图像灰度直方图分析,计算并统计其整体亮度情况,作为泡沫图像亮度值定量依据。结果表明:通过分析浮选图像RGB颜色值分布、颜色分级分类量化提取图像颜色特征值以及灰度信息,对泡沫颜色特征有一定代表性,并且提高泡沫图像颜色提取精度。通过BP神经网络,输入泡沫图像特征值颜色与品位信息并建立黑箱模型,通过样本训练,得到稀土品位预测值。     

基于极限树回归的浮选泡沫层厚度预测研究

泡沫浮选是一种重要的选矿方法，不同表面物理化学性质的矿物颗粒在药剂的作用下借助浮选机实现分离。浮选机的控制变量包括充气量、泡沫层厚度和药剂添加量等。泡沫层厚度是影响浮选指标的一个重要控制参数，同样，泡沫层厚度的准确测量也至关重要。传统的泡沫层厚度测量方式一般是采用传感器等装置来实现的，由于这些传感器往往需要与矿浆直接接触，所以有时会因机械故障或信号干扰而造成测量值的误差。 针对传统测量手段存在的问题，本文提出了一种浮选泡沫层厚度的软测量方法。运用极限树回归ETR方法，以浮选过程中原矿品位、入料流量、入料浓度、入料粒度、充气量、泡沫稳定度和泡沫移动速度为输入变量，建立预测模型，实现了浮选泡沫层厚度的有效预测。     

Froth-based modeling and control of flotation processes

This paper illustrates a new way for modeling and control of flotation processes based on froth appearances. As shown our previous work [Liu, J., MacGregor, J.F., Duchesne, C., Bartolacci, G., 2005. Monitoring of flotation processes using multiresolutional multivariate image analysis. Minerals Engineering 18 (1), 65–76], scores of the MR-MIA features can be viewed as numerical estimates of froth status or health. Therefore, scores of the MR-MIA features can be directly used in froth control as well as in froth modeling by employing the scores as process outputs (dependent variables).When applied to real froth images and corresponding process data, PLS regression provides good R² (the fraction of variance of dependent variables explained by the regression model) and Q² (the fraction of variance predicted for dependent variables not used in the regression model) values for both steady-state and dynamic causal models. Simulation study shows that a controller designed using the steady-state causal model provided control performances which were very satisfactory in achieving desired froth appearances.     

大型浮选机自动控制——可编程调节器在工业控制中的应用

对我国研制的KYF—38型大型浮选机的控制对象特性进行了分析。对浮选机矿浆液面检测,提出了矿浆液面和泡沫层之间无明显分界面的模糊概念。针对选矿厂的气源情况,在充气量控制回路中,采用了提高执行机构比例度和设置控制死区的方式来改善充气量控制特性。控制系统在药剂、给矿条件不变情况下,以充气量和矿浆液面作为控制参数,实现铜粗选泡沫中的品位控制。控制系统采用了集散型的可编程调节器,工作可靠,组态灵活,其性能满足设计的要求,并通过工业试验证明该系统是切实可行的。     

Flotation frother mixtures: Decoupling the sub-processes of froth stability,froth recovery and entrainment

The flotation process consists of two distinct phases: the pulp and froth phase. One of the main roles of the froth phase is to create a suitable environment for the separation of floatable, valuable minerals from non-selectively recovered, entrained gangue minerals. As a result the froth phase plays a significant role in the metallurgical performance of industrial flotation cells. Froth stability is important for the recovery of valuable minerals. However, a stable froth may contribute to increased entrainment and, consequently, a lower grade.This study compares the effect of frother mixtures with that of their single component frothers on the froth stability, froth recovery and entrainment of a platinum-bearing UG2 ore using polyglycol and alcohol frothers. The study showed that frother mixtures resulted in a greater froth stability than either of their component frothers. The increased froth stability was reflected in increased froth recoveries and greater overall recoveries. However, the important aspect in the use of frother blends was that they altered the froth structure and resulted in a lower degree of entrainment. This, together with the increased recovery, resulted in higher grades of valuable mineral recovered to the concentrate when using the frother mixtures.     

The effect of the reagent suite on froth stability in laboratory scale batch flotation tests

In batch flotation tests conducted on ores from the Merensky reef, changes in froth stability invariably occur with variations in the reagent suite. The main reagents are collectors (primary and secondary), activators, depressants and frothers. Since the particles entering and leaving the froth in a batch flotation system are continuously changing, the stability of the froth can vary. Under these conditions the simplest measure of froth stability is the measure of water recovery at a fixed froth height. The batch flotation system developed at UCT allows for the separation of gangue which is entrained relative to gangue which is floated. It has been found that the presence of naturally floatable gangue (NFG) leads to froth stabilisation, whereas the presence of hydrophobic sulfide minerals may lead to destabilisation of the froth depending on the hydrophobicity (contact angle) of the sulfide minerals. This can vary with ore type since particle shape and amount of particles present can influence the extent of destabilisation. At low depressant dosages sodium isobutyl xanthate (SIBX) always results in lower froth stability than sodium ethyl xanthate (SEX). The frothing nature of dithiophosphate leads to increased froth stability and the addition of copper sulfate results in destabilised froths. Increasing depressant dosage reduces the stabilising influence of NFG and the depressant type (guar gum or CMC) also affects froth stability. Frother can be used in an attempt to overcome the destabilising effects of high depressant dosage. This work examines the effect of variations in the reagent suite and uses water recovered at a fixed froth height as an indication of froth stability in order to analyse these effects on the recovery of sulfide minerals, floatable gangue and entrained gangue.     

泡沫降尘技术在枣庄滨湖煤矿的实验研究

降尘泡沫作为一种新兴的除尘工艺,具有优良的润湿性、覆盖性和黏附性,泡沫与粉尘之间存在的各种效应之间相辅相成,强化了泡沫降尘效率;设计的泡沫降尘工艺,利用井下已有的高压水和压缩风流为动力,通过添加器添加发泡剂,经与发泡器产生高性能泡沫,最后经喷头喷洒至掘进面,进行降尘。通过滨湖煤矿掘进面的现场测试,得出了采用泡沫降尘技术,降尘效率高可达80%,降尘后能见度在6m以上,降尘效果非常明显。     

Case studies on the performance and characterisation of the froth phase in industrial flotation circuits

This paper deals with two separate case studies investigating the froth phase performance and characterisation of two industrial rougher/scavenger flotation circuits. Froth phase performance was quantified using a mass balance approach to estimate froth zone recovery. Measured characteristics of the froth phase included frother solution concentration determined by gas chromatography, and the time taken for an equilibrium froth sample to decay to one-half of its original froth height. The latter measurement is referred to as the ‘froth half-life’ and is strongly linked to froth stability. Special methods and techniques developed to preserve frother in solution and to measure froth half-life are briefly described. The frother type in the first case study was a mixture of straight and branched alcohols, whilst the frother type in the second case study was a mixture of alcohols, aldehydes and triethoxybutane. The first case study focussed on a flotation circuit treating a low grade ore containing only a small fraction of floatable copper sulphide minerals, while the second case study focussed on a flotation circuit treating a higher grade complex sulphide ore containing significant quantities of chalcopyrite, galena, sphalerite and pyrite.It was found that froth zone recovery of valuable mineral generally decreased down-the-bank of the two industrial rougher/scavenger circuits. Moreover, decreases in froth zone recovery significantly limit the overall cell recovery of valuable mineral achievable from the plant scavenger cells. However, the decrease in froth zone recovery could not be linked to the removal of frother from the pulp solution to the concentrate product in the preceding rougher flotation stages. Measurements of residual frother in solution suggested that, approximately, only 5–10% of the added frother was removed into the rougher/scavenger concentrate, with the remainder appearing in the scavenger tailings. This finding suggested there was apparently adequate frother in solution in the scavenger stages.There was, however, a correlation to the froth half-life, with the froth half-life also generally decreasing down-the-bank. A simple, empirical model, based on the froth half-life and froth residence time of gas, is proposed here to predict froth zone recovery. Further, it is proposed that the froth stability, as measured by the froth half-life, is strongly linked to the presence of particles in the froth, with poorly mineralised scavenger froth characterised by a short half-life and, potentially, a low froth zone recovery. The importance of particles on froth stability was confirmed in separately conducted laboratory experiments. These experiments also demonstrated the wide variation in froth stability behaviour between different frother types.     

Froth recovery measurements in an industrial flotation cell

The froth phase serves an important role in upgrading the final concentrate in flotation. At present, the techniques that are used in the mineral industry to determine the effect of froth phase on the metallurgical performance of plant scale flotation cells have limitations.The aim of this paper is to investigate the performance of the froth in an industrial flotation cell. A unique device has been developed which is able to decouple the froth zone from the pulp zone. The device consists of two concentric tubes. The inner tube acts as a dropback collection chamber or catcher. The particles that return from the froth phase fall directly into the catcher and are collected as froth dropback. This technique is capable of measuring plant scale flotation cell froth recovery as well as providing valuable information on froth dropback particles.The froth recovery measurements were carried out in a rougher bank of a copper concentrator treating sulphide minerals. The dropback device is designed so that it can be immersed into an industrial size flotation cell and plant froth recovery measurements can be taken at any given location. During the experiments, the bubbles laden with valuable mineral particles entered the device from the flotation cell, subsequently rising to form a froth layer at the top of the device. The particles that detached or drained from the froth zone were collected in the dropback collection chamber whereas the concentrate sample was collected through a launder. By sizing and chemical analysis of the concentrate and dropback samples, the froth recovery was estimated on the basis of the valuable component. The effect of air rate on the froth recovery was also investigated. Metallurgical grades of the froth dropback device samples for different particle size ranges were compared to those of the concentrator to better understand the froth dropback mechanism.