【作者】 李琳；

【导师】 刘炯天；

【作者基本信息】 中国矿业大学 ， 矿物加工工程， 2010， 博士

【摘要】 随着我国铁矿资源开发力度逐步加大,贫细难选赤铁矿的开发已经势在必行。目前,围绕赤铁矿分选已经形成了弱磁-强磁-阴离子反浮选的较成熟分选工艺,但随着资源贫化,以及矿物粒度越来越细,其中的阴离子反浮选工艺逐渐暴露出分选效率低、工艺流程长、选矿成本高等问题。因此,在整体工艺框架下,开展高效的反浮选分选方法、设备和工艺研究具有十分重要的意义。首先开展了贫细赤铁矿的工艺矿物学和可浮性研究,分析了贫细赤铁矿的矿物学特性,揭示了“贫、细”对赤铁矿分选过程的显著影响,研究了贫细赤铁矿的可浮性过程特征。本文系统分析了各种分选方法及过程,特别是旋流-静态微泡浮选柱分选方法及过程的特点,提出了利用浮选柱特别是柱内管段高紊流矿化以及粗精选一体的多流态梯级强化过程来提高贫细赤铁矿的分选效率、强化分选工艺的思路。本论文对基于射流的管段高紊流矿化过程的研究始于气泡特征。指出了单个气泡在管段内运动过程中直径的变化规律,并采用摄像-图像处理法首次对管段内气泡尺寸的分布规律进行了研究。利用压差法研究了基于射流的管段内气含率的变化和分布规律。考察了循环压力、吸气量、柱体背压以及起泡剂用量条件对管段整体气含率的影响,揭示了管段内局部气含率的分布规律。利用激光多普勒测速仪(LDV)研究了基于射流的管段内单相流场的二维速度场分布,掌握了管段内单相流场的速度分布特征。利用FLUENT软件对基于射流的管段内的流场进行了单相和气液两相流数值模拟研究。研究结果表明:管段单相流数值模拟得到的速度场分布规律与利用LDV得到的实验结果在总体趋势上是一致的,说明数值模拟技术作为研究管段流场的手段是合理的。在此基础上,通过管段气液两相流数值模拟分析了管段内速度、压力、湍流动能和气含率的分布规律,掌握了管段内的基本流场特性,揭示了管段直径、柱体背压和气泡直径对管段内流场的影响。本文开展了基于中矿的管段高紊流矿化的浮选动力学研究,推导出了管段的浮选速度常数、平均停留时间和浮选回收率的表达式。本文最后开展了贫细赤铁矿分选试验研究。建立了实验室分选系统和柱式短流程工艺研究系统(工业分流试验系统),通过分选试验研究了高效柱式粗选设备的分选过程,开发出“粗-扫”两段式柱式短流程工艺,与浮选机工艺相比,简化了流程,在精矿品位相近的情况下,回收率提高了8.25个百分点,强化了对微细粒矿物的回收,该项研究也填补了我国铁矿选矿技术的空白。在工艺研究的基础上,结合磁铁矿柱式分选工艺工业应用的经验,进行了柱式分选设备的适应性改进和一粗两扫中矿顺次返回流程的工业系统设计。更多还原

【Abstract】 With the rapid development of exploration of iron resources, it is imperative to utilize lean fine hematite. At present, separation technology of weak magnetic-high intensity magnetic-anionic reverse flotation has matured for hematite, but with the depletion and increasingly fine particles of hematite, anionic reverse flotation technology gradually exposes the problems including low separation efficiency, long process flow and high separation cost, etc. Consequently, it is rather important to develop the efficient separation methods, equipment and technology based on the whole technology framework.Firstly, studies of process mineralogy and floatability of lean fine hematite were conducted; the mineralogical properties were analyzed; significant influences of“lean and fine”on separation process of hematite were revealed; and the floatability process characteristics of lean fine hematite were studied. Features of various separation methods and processes, especially FCSMC, were systematically analyzed, and the idea that enhancement of separation efficiency of lean fine hematite and intensification of separation technology could be achieved by using high turbulence mineralization of pipe section in FCSMC and multiple-flow-pattern gradient intensifying process of integrated roughing and cleaning was proposed.Study of high turbulence mineralization in pipe section based on jet started from bubble characteristics. The change in single bubble diameter in motion was analyzed; meanwhile, bubble size distribution in pipe section was studied for the first time with application of photo-image method. Pressure difference method was used to study the variation and distribution of gas holdup in pipe section based on jet. Effects of cycle pressure, gas flow rate, back pressure and frother dosage on total gas holdup of pipe section were investigated; and distribution of local gas holdup of pipe section was disclosed.The velocity distribution characteristics of single phase flow field in pipe section based on jet were mastered by study of corresponding 2-D velocity distribution using Laser Dopper Velocity (LDV). FLUENT software was used to conduct single-phase and gas-liquid two-phase fluid dynamic numerical simulation of pipe section based on jet. The results show that generally velocity distribution of single phase numerical simulation shares the similar tendency with that of LDV, indicating that it is reasonable to study flow field of pipe section with numerical simulation technology. Moreover, the gas-liquid two-phase numerical simulation was used to analyze the distributions of velocity, pressure, turbulent kinetic energy and gas holdup, and basic flow field characteristics were mastered. Besides, the influences of diameter of pipe section, back pressure and bubble size on flow field of pipe section were revealed.Expressions of flotation rate constant, average residence time and recovery for pipe section were derived from flotation kinetics research of highly turbulent mineralization in pipe section based on cycle middling.The separation research of lean fine hematite was carried out lastly. Lab separation system and column-shortened-process research system (industrial divergent stream test system) were built, through which separation process of high efficient column roughing equipment was studied. And“roughing- scavenging”two-segment column shortened process was developed, which was a simplified process with a dramatic increase of 8.25% in recovery in the case of similar concentrate grade comparing to flotation machine technology. It strengthened the recovery of micro-fine minerals. This research fills in the blank of iron ore processing technology in China.On the bases of technology development and industrial application of column separation technology for magnetite, modification of adaptation of column separation equipment was conducted and one roughing - two scavengings - middling sequential returning process was designed.更多还原