矿物材料分离与富集过程中系统优化问题研究

【作者】 许炳梁；

【导师】 陆建生； 刘殿文；

【作者基本信息】 昆明理工大学 ， 材料学， 2014， 博士

【摘要】 分离与富集是获得矿物材料的重要技术,目前针对矿物材料分离与富集过程进行系统优化的研究较少。钛铁矿是一种重要的矿物材料,我国钛铁矿资源储量处于世界第一。目前,钛铁矿分离与富集技术存在回收率低、工艺流程复杂的特点。论文以攀枝花选铁尾矿中钛铁矿的“全粒级-全浮选”回收工艺为例,探讨钛铁矿富集与分离过程中的系统优化和参数降维问题。论文以表面能参数为矿物可浮性度量,采用多粒级含量与浮选指标相关性分析、混料试验设计和响应曲面法对工艺过程中的参数进行了有效地降维处理和优化,对浮选工艺流程的系统优化有较好的指导作用。本论文从经过捕收剂作用的钛铁矿表面性质出发,根据表面能参数与矿物可浮性的关系选择了钛铁矿的捕收剂。首先对表征矿物材料表面性质的重要参数一接触角进行研究,建立了基于霍夫变换的全新接触角测量方法。该方法具有自动检测接触点、高准确性和鲁棒性的特点。用这种方法对接触角进行测量,便可得到固体表面能。测试了几种常见矿物改性前、后的表面能参数和四种合成材料的表面能参数。又对以上几种表面在减压条件下析出气泡的能力进行了研究,发现以上几种表面析出气泡的能力与其Lewis碱分量的相关性很大。本论文将这种析出气泡的能力叫做“亲气性”。通过这种亲气性,优选出了钛铁矿的捕收剂SYB1#,在无抑制剂环境下对SYB1#和其它两种捕收剂的实际浮选效果进行了对比,试验证明SYB1#的捕收性和选择性均优于其它两种捕收剂。对于磨矿的优化,提出了多粒级含量与浮选指标相关性分析确定最佳磨矿细度的方法,也分析研究了磨矿产品的多个粒级含量对浮选指标的影响。发现原矿直接入磨的方式造成大量微细粒级的产生,不利于钛铁矿的浮选。后对磨矿流程进行调整,采用筛分入磨方式进行磨矿。筛分入磨方式能产生较多-0.074～+0.045mm粒级。通过浮选指标与多个粒级含量的相关性分析得到,-0.074～+0.045mm粒级含量越多对钛铁矿的浮选越有利。在探索得到适宜的磨矿方式和有利的浮选粒级后,确定了最佳磨矿时间为3-4分钟。粒级优化得到窄粒级的入浮选物料。混料试验设计用于选择抑制剂。通过pH=5,7,9时抑制剂的混料试验设计,定性地确定了抑制剂为羧基及纤维素钠(CMC)。抑制剂混料试验设计的研究结果表明,在酸性条件(pH=5),中性条件(pH=7)和碱性条件(pH=9)下,CMC的使用均能获得较高的粗精矿品位。只是使用CMC做抑制剂时,随着pH值的升高粗精矿的回收率急剧下降。通过响应曲面法单目标优化,得到了粗选段的较优结果。在捕收剂用量为1025g/t,抑制剂用量为1025g/t,矿浆pH=5的工艺条件下。粗选获得品位超过40%、回收率达到60%的粗精矿。在粗选中,抑制剂用量、捕收剂用量和pH值对粗精矿回收率的影响并没有表现出显著的交互作用。但是,捕收剂用量与抑制剂用量、抑制剂用量与pH值的交互作用却对粗精矿品位的影响表现得很显著。在精选过程中,发现捕收剂用量与pH值的协同效应对精矿的回收率表现出了显著的有益作用。针对品位和回收率的多优化问题提出了广义满意度函数的解决办法。采用广义满意度函数可以将多目标响应转化为单目标响应。通过对品位和回收率的多目标优化后,钛铁矿全浮选工艺精矿品位达到47%,回收率超过40%。浮选指标较现有强磁-浮选工艺指标有了较大的提高。浮选稳定性模拟试验得出,精选过程有较好的稳定性。工艺条件的波动仅会引起回收率的小幅下降,精矿品位的波动不如回收率敏感。除此之外,在浮选稳定性模拟试验中发现了“补偿效应”。该效应使得捕收剂用量、抑制剂给用量和pH值三因素引起精矿回收率的波动小于pH值引起回收率的波动。通过浮选模型与浮选指标的关系提出了“工艺参数空间”的概念,即工艺条件的接受域。根据“工艺参数空间”,研究者、生产者可针对精料的应用领域对精料的质量做出调整。通过捕收剂的强化改性使得钛铁矿精矿回收率得到进一步提升,精矿回收率达45%以上。且浮选体系所需pH值也得到相应的提高。更多还原

【Abstract】 Separation and enrichment are the processing techniques of mineral materials. There are however few studies on the topic. Ilmenite is an important mineral material. And ilmenite reserve of China is ranked first in the world. At present, a large quantity of erosion and complex technique are major problems in separation and enrichment of ilmenite. All size fractions flotation for recovering ilmenite from tailings of iron in Panzhihua area, Sichuan province, is taken as an example in the paper to explore optimal design and reduction of dimensions of the parameters in separation and enrichment. The dimensions of the parameters are reduced and optimization is satisfactorily achieved.The collector of ilmenite is selected rationally from the characters or parameters of modified surface. The surface parameters are obtained from the measurements of wetting angle on bulk materials or minerals. An innovative method based on Hough Transformation is put forward for the measurement of contact angle. The contact points are detected automately with more accuracy and higher robustness, when this method is applied. The behavior that the bubbles are formed from gas evolution on the bulk materials in a vaccum is studied in our work. It is found out that the behavior is strongly correlated with the proton acceptor component, which is one of the surface energy parameters. Specifically, the less proton acceptor component, the more bubbles formed on the bulk material."Aerophilic", which is defined to measure the behavior aboved, is referred to selection of ilmenite collector that is SYB1#. The flotation tests show that the collector is superior to two constrastive collectors.Single size feed is produced by grinding optimization. The correlation between the quality of concentrate and the distribution of particle size is analysed. Meanwhile, the analysis is used to grinding optimization. An amount of fine particle is produced in case of feeding to mill without any pre-processing. Indeed, the excessive fine particle is fatal to flotation. The optimized grinding with pre-screening produces less fine particle. The correlation analysis indicates that the particles in size-0.074～ +0.045mm are beneficial to ilmenite flotation. The optimized grinding time is3-4min.The mixture experiment design is applied to select the depressor. The depressor mixture experiment at pH=5,7,9shows that carboxymethyl cellulose sodium (CMC) is the efficient depressor to flotation. In addition, high grade concentrate is recoved when CMC is used. And the recovery increases with the reduction of pH value. The satisfying rough concentrate is obtained by Response Surface Methodology (RSM). The grade and recovery of rough concentrate is40%and60%respectively in the condition that collector dosage, depressor dosage and pH is1025g/t,1025g/t, and5respectively. In addition, the grade of rough concentrate is significantly influenced by two interactions:collector dosage and depressor dosage, depressor dosage and pH value. In concentration flotation, the positive synergistic effect between collector dosage and pH value is beneficial to the recovery of ilmenite concentrate.The general desirability function is defined to convert multi-objective into single objective. The quality of concentrate is raised by optimization of multi-objective. The recovery of concentrate reaches up to40%as the grade reaches up to47%. The simulation of parameters fluctuation indicates that concentration flotation works with high robustness. The fluctuation of parameters causes only a slight decrement of the recovery. In contrast, the grade of concentrate is immune to fluctuation. Besides, a phenomenon called "complemental effect" is found in simulation. In detail, the recovery variation resulted from the fluctuation of three parameters (collector dosage, depressor dosage and pH value) is less than the variation resulted from the fluctuation of pH value. The recovery of concentrate is increased to45%by the optimization of SYB1#. And the restriction on pH value is relaxed obviously.更多还原