【作者】 桂夏辉；

【导师】 刘炯天；

【作者基本信息】 中国矿业大学 ， 矿物加工工程， 2012， 博士

【摘要】 随着机械化采煤比例的提高和重介质选煤的快速发展，我国煤泥呈现微细化、高灰、连生体含量大等难选特点，煤泥分选问题进一步凸显。煤泥分选过程的完善程度直接影响到精煤产品的质量与产量、精煤和尾煤的脱水作业以及整个选煤厂的洗水平衡。然而，我国现有的煤泥分选过程仍存在回收能力弱、过程适应性差、通过牺牲处理量来保证回收率的缺陷，煤泥可浮性的非均匀性变化对煤泥分选过程设计提出了更高要求；实际生产又对分选设备大型化、精细化和适应性提出了更高要求。针对上述问题，论文以过程机理分析、过程特征试验、过程强化试验和工业实践为主线，选取唐山开滦矿区难选烟煤和河南神火矿区无烟煤两种代表性煤泥为试验样品，对煤泥分选过程强化及两段式分选机理进行了系统研究，得到了如下研究成果：研究了煤泥分选的可浮性过程变化特征。分析了唐山烟煤和永城无烟煤的浮选过程特征，研究了不同粒度级煤泥的浮选速率常数变化特征，探索了浮选药剂用量、浮选机转速、充气速率、入料浓度等参数对浮选速率常数的影响；通过对浮选速度试验产品的粒度、密度和SEM分析，探明了细泥的浮选行为特征；并理论推导和实验室试验验证了浮选入料可浮性随着分选过程非线性变差的规律。研究了煤泥分选过程的能耗变化规律。建立了煤泥分选能耗测试系统，分析了不同能耗条件下的浮选产品特性，探索了浮选功率输入与浮选速率常数的函数关系。研究表明，随着浮选的进行，上浮单位精煤可燃体回收率所消耗的能量逐渐增加，粗颗粒连生体和微细粒难浮煤粒需要在高能量条件下才能回收。提出了煤泥两段式分选过程。将煤泥分选过程分为快浮段和回收段，快浮段低能量输入快速浮出易浮物料，回收段高能量输入强制回收难浮物料；研究了两段式分选机理，从理论上证明了两段式分选过程与单段式分选过程相比的优势，即当浮选中物料的可浮性变化越大，则要求两段式分选过程一段与二段能量分配的差值越大；提出了基于能量输配的浮选过程设计理念，即构建越来越强的能量条件来适配物料可浮性在浮选中越来越差的物性变化特征，以实现过程设计与物性特征的最佳耦合，达到最佳的矿化反应状态。研究了基于柱分选的两段式煤泥分选过程。以旋流-静态微泡浮选柱为基础，结合两段式分选方法，设计了FCSMC10002000两段式柱分选试验装置，并在开滦集团钱家营选煤厂进行了连选试验，从浮选流体动力学角度研究了两段式柱分选的回收率模型，并通过连选试验对模型进行了验证。结果表明，两段式柱分选过程在整体处理能力和粗颗粒回收能力上均优于单段式柱分选过程。根据两段式柱分选的原理和煤泥浮选过程特征，确定了两段式柱分选设备的结构原型及放大准则。设计了FCSMC30006000大型两段式柱分选设备，并在开滦集团钱家营选煤厂和神火集团薛湖选煤厂得到了应用和验证，与单段柱分选设备相比，其处理能力和过程适应性均得到改善和提高。进行了难选煤泥分选的工艺强化研究。实验室中煤煤岩解离再选试验表明，在精煤灰分相当情况下，煤岩解离再选的工艺流程与原煤直接浮选相比，其精煤可燃体回收率提高8.12个百分点；难选煤泥工艺强化连选试验表明，两段式柱分选过程一段采取低压力、小中矿循环量回收易浮物料，二段采取高压力、大中矿循环量回收难浮矿物，中间连生体颗粒磨矿解离后再选回收，在精煤灰分相近条件下，可燃体回收率高于常规分选工艺10个百分点以上。提出了基于二次资源回收的高灰难选煤泥高效分选工艺。在提高精煤质量方面，提出了粗精煤入沉降过滤离心机脱水后滤液再精选流程，减小了精选压力和系统循环量；在提高精煤可燃体回收率方面，提出了粗选尾煤入旋流器浓缩分级、旋流器底流入高频筛脱水、高频筛筛上物入球磨机磨矿解离后再选的工艺流程，在开滦集团钱家营矿选煤厂建立了矿浆处理能力为400m3/h的工艺系统。工业应用结果表明，根据中煤含量的不同，在精煤灰分相当情况下，过程强化高效分选工艺与浮选机一粗一精流程相比，精煤可燃体回收率提高5-10个百分点。论文共包含131幅图，58个表格，156篇参考文献。更多还原

【Abstract】 With the improvement in the proportion of mechanical coal mining and rapiddevelopment of heavy-medium coal preparation, China’s fine coal is gradually characterizedby size reduction, ash increase and intergrowth content raise. Fine coal separation problembecomes prominent. Perfect degree of fine coal separation process directly affects the qualityand quantity of clean coal products, dewatering operation of clean coal and tailings, andwashing water balance of the whole coal preparation plant. However, there are still manydefects as weak recovery, weak flexibility, and contradiction between recovery andproductivity in the existing fine coal separation process in our country. Inhomogeneouschanges of fine coal flotability put forward higher requirement on fine coal separationprocess design. Actual production raised higher demands for large-scale, fining andadaptability of separation devices. In view of the above difficult problems, taking processmechanism analysis, process characteristics test, process intensification test and industrialpractice as the main line, the hard-to-float bituminous coal of Tangshan Kailuan mine andanthracite coal of Henan Shenhuo mine these two kinds of representative slime were taken asresearch samples, and fine coal separation process intensification and two-stage separationmechanism were systematically studied. The following findings are obtained:Flotability process features of fine coal separation were studied. Flotation processcharacteristics of Tangshan bituminous coal and Yongcheng anthracite coal were analyzed.Changes in characteristics of the flotation rate constant of different size fine coal wereresearched. Effects of parameters as the amount of flotation reagents, flotation machinerotation rate, superficial gas velocity, and feeding concentration on flotation rate constantwere explored. By analyzing the size distribution, density and SEM of the products from thetests of flotation dynamics, flotation process behavior of fine mud was provened. Theoreticalderivation and experiment verify the common law that the floatability of floating materialbecame poor with the flotation process.Change rule of energy consumption of fine coal flotation was studied. Fine coalseparation energy consumption testing system was established, flotation productscharacteristics under different energy consumption conditions were analyzed, and therelationship between energy input and flotation rate constant was also studied. The resultsshow that the energy consumption for floating unit mass of clean coal gradually increased with the flotation process. Coarse intergrowth and micro-fine hard-to-float coal particlescould only be recycled under high energy condition.Two stages separation process of fine coal was put forward. Fine coal separationprocess was divided into fast float section and recycling section. Easy floating materialswere recycled with low energy in fast float section, and hard-to-float materials werecompulsorily recycled with higher energy in recycling section. Two stages separationmechanism was studied. The superiority of two stages separation process compared withsingle stage separation process was proved theoretically, that was to say, the more thefloatability changes in flotation, the bigger the energy distribution difference between onestage and two stage separation process. Flotation process design concept based on energytransmission and distribution was put forward. To construct more and more strong energyconditions to adapt the physical property changes of the minerals in flotation, so as to realizethe best interconnection of process design and physical property characteristics and achievethe best mineralization reaction condition.Two stages fine coal separation process based on column flotation was studied.Combining two stages separation methods, a two-stage column separation test device(FCSMC1000×2000) based on Cyclonic-Static Micro-bubble Flotation Column wasdesigned, and tests were conducted in Qianjiaying Coal Preparation Plant, Kailuan Group.From flotation fluid dynamics perspective, recovery model of two stages column separationprocess was studied, and the reliability of models was tested and verified.The results showthat, two stages column separation process was both superior to single stage flotation columnin processing power and coarse particle recovery capability.According to separation principle and process characteristics of fine coal flotation,magnifying standard and structure prototype of two stages column separation device weredetermined. Large-scale two stages column separation equipment (FCSMC3000×6000) wasdesigned and applied in Qianjiaying Coal Preparation Plant, Kailuan Group and Xuehu CoalPreparation Plant, Shenhuo Group. The results show that, both the processing capability andadaptability of two-stage column separation equipment were improved averagely comparingwith that of single stage.Process Intensification of hard-to-float fine coal flotation was studied. The results ofcoal rock dissociation and re-separation tests in the laboratory show that, when clean coalash content equals, recovery of clean coal combustible in re-separation process based on coalrock dissociation were increased by8.12percentage points compared with raw coal directflotation. The results of technological intensified separation tests on hard-to-float fine coal show that, the first stage of the two-stage column flotation process recycled easy floatingmaterials under the condition of low pressure and small circulation, the second stagerecycled difficult floating minerals under high pressure and big circulation, and theintergrowth particles were recycled by re-separation process based on coal rock dissociation.In the condition of similar clean coal ash content, the recovery of combustible was higherthan conventional separation process by10percentage points.High efficient separation technology of hard-to-float high ash fine coal based on secondresource recovery was put forward. In terms of improving concentrate’s quality, there-separation process of filtrate from screen bowl centrifuge treating after the dehydrationprocess of rougher clean coal were designed in this paper, and this process reduced thecleaning pressure and system circulation. In terms of improving concentrate recovery ofcombustible, the technological process describing as classification of rougher tailings usingcyclone+dewatering of underflow from cyclone using high frequency screen+grindingdissociation and re-separation of oversize products from high frequency screen was putforward. The system with a handling capacity about400m3/h was set up in Qianjiaying coalpreparation plant in Kailuan Group. Industrial application results show that, under thecondition of similar clean coal ash content, combustion recovery of clean coal from thestudied process indicated an increase about5-10percentage points comparing with that ofonce rougher and once cleaner based on conventional flotation cell.This paper contains131pictures,58forms and156pieces of references.更多还原