旋流微泡浮选柱提高精煤回收率的试验研究

针对煤炭试样细粒级含量高的特性,依据浮选机试验确定的最优试验工艺条件,利用旋流微泡浮选柱进行了提高精煤回收率的试验,取得了精煤灰分7.78％、产率70.78％的良好分选指标.比较柱浮选和常规浮选试验,结果表明,在精煤灰分相接近的情况下,柱浮选的精煤产率要高9.32％.     

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.     

粉煤灰中难浮未燃炭的柱式浮选脱除试验研究

采用粒度分析、X射线衍射、接触角测量和X荧光分析等手段对矿样的物理化学性质进行表征,从表面性质的角度探讨未燃炭可浮性较差的内在原因;研究黏性起泡剂KD对浮选体系的泡沫稳定作用;采用实验室型旋流-静态微泡浮选柱研究未燃炭的柱式浮选行为。研究结果表明：黏性起泡剂可有效提高浮选体系的泡沫稳定性,在起泡剂KD用量400 g/t、表观充气速率1.8 cm/s、泡沫层厚度150～200 mm、浮选柱循环压力0.22 MPa的优化试验条件下,可以得到烧失量3.15%的低炭灰产品,炭脱除率达91.88%。     

煤粉粒度测试技术现状及发展

介绍了目前国内外有关煤粉粒度分布测试技术的各种手段和方法,综合评述了其技术现状和特点,比较了各种测试方法的优缺点.     

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.     

浮选柱与浮选机分选煤泥的试验研究

旋流气泡浮选柱是近年来广泛推广使用的浮选设备,通过分析浮选柱的工作原理及优点,进行浮选柱与浮选机的对比试验研究。结果表明:细粒煤分选时,浮选柱比浮选机具有明显的优势。     

An evaluation of the role of particle size in the flotation of coal using different cell technologies

A large variety of new flotation cells has been introduced in the last few years, probably as a result of the successful introduction of column flotation in the minerals processing industry. In common with the column cell, a number of these new cells employ an essentially quiescent separation zone. However, a number of novel cell designs have been introduced that use agitation mechanisms similar to those employed on conventional flotation cells. The aim of this investigation was to evaluate flotation behaviour in both an agitated and non-agitated environment, particularly with respect to particle size. A hybrid ‘agitated’ column cell was designed for the investigation, and the operation of this unit was compared to that of a column cell, and to a batch flotation cell, on a laboratory scale. The testwork was conducted on coal fines, as problems with the flotation of coarse coal particles in a column cell had previously been identified. It was demonstrated that the addition of an agitated stage to a column cell can significantly improve the coarse particle recovery in comparison to the conventional column cell, while maintaining good selectivity in the fine sizes.     

基于高浓度煤泥水的柱式主再浮试验研究

分析了目前重介质选煤工艺下选煤厂入浮煤泥水浓度升高对浮选柱分选作业带来的不利影响,提出采用柱式主再浮工艺解决高浓度煤泥水浮选的思想,通过试验验证了柱式主再浮工艺的可行性。柱式主再浮工艺通过主浮保质、再浮保量可保证浮选效果,解决了浓度高煤泥水浮选效果差的问题。通过正交试验研究影响柱式主再浮工艺分选效果的工艺参数,对精煤产率的影响程度大小为主浮压力>再浮压力>浓度;对精煤灰分的影响程度大小为主浮压力>浓度>再浮压力;对浮选完善指标影响程度大小为主浮压力>再浮压力>浓度。     

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。      

The effect of potential heap construction methods on column bioleaching of copper flotation tailings containing high levels of fines by mixed cultures

It is known that excess fines may reduce heap permeability and block channelings of leachate flow in heap bioleaching operation, and further cause low metal recovery. The purpose of this investigation was to compare the effects of three potential heap construction methods including layered heap construction method (Method A), agglomerate heap construction method (Method B) and pelletized sintering heap construction method (Method C) of copper flotation tailings on column bioleaching behaviors. In the three heap construction methods, the tailings copper extractions achieved 54.61%, 60.09% and 43.93%, respectively, in Method A, B and C on day 83. Copper extraction of Method B reached maximum. In addition, compositions and structures of microbial communities were examined using Illumina Miseq sequencing technology based on 16S rRNA amplification. Acidithiobacillus, Leptospirillum and Ferroplasma were main microorganisms in three heap construction methods. Detrended correspondence analysis showed that Method C had little effect on microbial communities. These studies revealed the influence of different heap construction methods on leaching behaviors and microbial dynamics, which will facilitate the bioleaching of fine-grained ores.     

难选煤泥可浮性分析及解离浮选工艺研究

以选煤厂细粒煤泥为研究对象,分析了该煤泥的煤质特征。探索了改变充气量对浮选结果的影响,结果表明该煤泥为难选煤泥,常规浮选很难得到低灰分的精煤产品。对浮选精煤产品进行粒度与密度组成分析,表明解离不充分与细泥夹带是造成精煤灰分偏高的主要原因。采用原煤分级 粗粒级磨矿浮选工艺,可有效降低精煤产品的灰分。     

旋流-静态微泡浮选柱用于铜精选的试验研究

为提高某斑岩型铜矿的精矿品位,引入旋流-静态微泡浮选柱进行精选工艺试验研究,以浮选柱两段替代原浮选机五段精选流程,可获得品位为26.45%的铜精矿,精选作业回收率达93.66%,并有利于金、银、钼等伴生金属的富集和回收.     

气肥煤浮选降灰试验研究

为考察山东济北矿区气肥煤煤泥降灰的可行性,分别以柴油和仲辛醇(分析纯)为浮选药剂,采用拓展化浮选试验的方法,重新设计浮选流程,对煤泥进行了粗选试验和一次精选试验.试验结果表明:最佳浮选药剂用量为1.0 kg/t、药剂比为5:1,矿浆浓度为80 g/L、搅拌速度为1 800 r/min,精选多次刮泡条件下,时间累计在15...     

Development of an index for the floatability of Indian coal fines

Batch flotation experiments were carried out on four different Indian bituminous coal samples in the size -74 μm at various levels of variables. It has been noticed from the results that at any flotation time, the yield of concentrate Y (t) follows a linear relationship of the following form with the amount of water W(t) reporting to the concentrate. Y(t)=F_w(t)+E_w(t)·W(t)The intercept value F_y(t) which is termed as the true flotation component of yield when hypothetically no water reports to the concentrate has been found to increase with flotation time as given by the equation F_w(t)=F_w(∞)·[1−exp(−k_w·t)]Based on these observations, an index called “floatability index (FI)” has been proposed to quantify the response of coals towards froth flotation. This index is defined as The floatability index varies from 0 to 100. Consequently, the higher the value of the index for any coal, the better is its response towards flotation. The floatability index has been found to be specific for a given coal and is independent of process variables like reagent dosages, solid content of feed slurry and flotation time.     

Two-stage fast flotation of coal tailings using reflux flotation

Low pulp density and low grade slurries in the coal and minerals industries are discharged as waste to tailings dams, incurring significant losses of valuable particles. This paper investigates the rapid processing and cleaning of hydrocyclone overflow coal slurry using two laboratory scale Reflux Flotation Cells in series as a means to economically beneficiate low quality tailings streams. The Reflux Flotation Cell incorporates a novel arrangement of inclined channels to enhance bubble-liquid segregation, enabling extremely high gas rates and liquid rates per unit of vessel area. Hence, in the first stage, fast flotation is employed to rapidly recover fine coal particles using a feed flux of 11.4 ± 0.5 cm/s, up to an order of magnitude increase in the throughput rate over conventional flotation systems. First stage product was then sent to a second stage for counter-current washing using fluidisation wash water to produce a fully deslimed product, having ash percent in agreement with the minimum ash attainable using flotation as determined through tree flotation analysis. The results demonstrate the potential for two-stage Reflux Flotation to deliver high throughput at a high separation efficiency from low quality slurry, with a fivefold reduction in the required vessel footprint, thus overcoming the principal economic deterrent of having to install banks of large-scale flotation cells.     

煤泥自载体浮选

粒度组成细、高灰细泥含量大的煤泥浮选时,浮选精煤易于超灰且精煤产率低、生产操作困难。针对这些问题,在总结载体浮选理论的基础上,研究了以浮选精煤作为自载体改善煤泥浮选效果的作用和机理。结果表明:用浮选出的精煤作自载体可显著改善煤泥的浮选效果。随自载体量的增加,精煤产率、浮选完善指标、尾煤灰分均提高,浮选精煤灰分降低。乌海煤泥采用该工艺浮选时,确定出最佳自载体用量为入浮煤泥的10%,加入自载体经4次循环后即可达到稳定的浮选效果,浮选精煤产率提高7.11%、灰分降低1.14%,浮选完善指标提高7.25%。EDLVO理论的计算研究表明,精煤本身的疏水性和捕收剂在煤粒表面吸附产生的疏水力,促使细煤粒黏附于粗颗粒载体,细颗粒间也会发生疏水絮凝,改善了浮选环境和浮选效果。     

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。     

浮选柱及精煤压滤机回收煤泥的实践研究

分析了兴发选煤厂煤泥水处理系统的改造原因,并介绍了改造后的工艺流程主要特点,指出在原料煤性质、入料浓度相同的情况下,采用以浮选柱与加压过滤机作为浮选精煤压滤机联合使用,可提高选煤厂煤泥水处理能力和精煤产率。     

中心选煤厂煤泥浮选工艺改造

为解决新矿内蒙能源公司中心选煤厂精煤综合产率低的问题,决定采用FCMC型旋流微泡浮选柱对原生产工艺进行改造。实践结果表明:旋流微泡浮选柱分选工艺在该厂的应用不仅满足了精煤灰分≤8.50%的要求,提高了精煤综合产率,而且为企业带来丰厚的利润。