浮选泡沫的形成、稳定和破灭的力学分析

以浮选泡沫为研究对象,对球形气泡形成、气泡兼并、气泡表面层形成、矿粒黏附气泡、泡沫的形成以及泡沫的破灭过程进行力学分析.结果表明,搅拌形成的不规则气团在液相中受到界面附加压强作用趋于球形;气泡之间的压强差引起气泡兼并;新生表面层的内外界面的附加压强维持住气泡液上结构;液下气泡和液上气泡以不同方式与矿粒黏附;分子间作用力使气泡黏贴,形成稳定的泡沫层结构;在泡沫层中,破裂气泡能引起周围气泡的膨胀.     

湍流态下浮选矿化速率数学模型

根据湍流态下矿粒、气泡的运动情况,引用分子运动理论及胶粒凝并理论,综合考虑流体动力及表面力的作用,建立了矿粒与气泡碰撞矿化的浮选速率数学模型。经纯矿物浮选试验验证,表明所建立的数学模型合理可靠。     

煤炭浮选中存在的问题与解决的技术措施

选煤厂煤炭浮选还存在一些问题,如细粒煤的浮选选择性不好等。解决问题的技术措施主要是增加矿粒行为尺寸、减少气泡尺寸、在离心力场下进行浮选、强化浮选药剂的作用等。     

微细粒锡石的两液浮选

本文研究了-5微米锡石的两液浮选,并与相应条件下的常规浮选进行了比较。结果表明,两液浮选工艺优于泡沫浮选,锡石回收率可达99.3％,精矿含90.0％SnO_2。研究发现,捕收剂在两液浮选中起着三重作用:(1)使矿粒疏水;(2)使油相乳化;(3)影响油滴表面电性。油液表面的ζ-电位负值比矿粒-溶液间的ζ-电位还大,是两液浮选中的一个重要影响因素。两液浮选比泡沫浮选优越的原因:(1)两液浮选中产生的油/水界面较大,提高了细粒矿物的碰撞几率和附着面积;(2)油相体系的Hamaker常数比气相体系的Hamaker常数大,因而油滴比气泡更有利于疏水矿粒的粘附。     

铝土矿浮选泡沫消泡研究

以河南混合铝土矿浮选精矿泡沫为研究对象, 分析铝土矿浮选泡沫的稳定原因. 采用物理方法和化学方法, 进行三相泡沫的消泡研究. 结果表明: 油酸钠可以显著降低水溶液体系的表面张力, 同时微细疏水矿粒在气泡表面的吸附降低了气泡表面的排液速率, 并增强了气泡的机械强度, 导致铝土矿浮选泡沫稳定;另外, 转速对机械搅拌消泡有较大的影响, 消泡效果随转速的提高而增强;磷酸三丁酯、 Foamban-ms-575和BD3037对两相泡沫体系具有很好的消泡作用, 但在三相泡沫体系中由于在泡沫表面铺展速率的限制, 消泡效果并不明显;利用机械搅拌和添加消泡剂, 可以在较低的转速下, 大大改善消泡效果.     

起泡剂对硫化矿无捕收剂浮选的影响

起泡剂作用在无捕收剂浮选过程中较有捕收剂浮选过程更为显著。本文考查了起泡剂用量和种类对硫化铜矿石和钼铋硫化矿石无捕收剂浮选回收率以及精矿品位的影响。起泡剂用量增加导致精矿回收率明显增加。松醇油和丁基醚醇是硫化矿无捕收剂浮选的适宜起泡剂。探讨了起泡剂的作用方式。     

纳米气泡作用下的不同粒度煤泥浮选动力学特性

颗粒粒径的大小是影响浮选的重要因素,一般来说,浮选入料粒度过粗或过细都会对浮选效率与速率产生不利影响。纳米气泡由于尺寸小、比表面积大以及生存周期长等特质,逐渐成为浮选领域研究的热点,研究纳米气泡浮选过程中的颗粒粒度效应具有重要意义。本文采用水力空化作为纳米气泡产生方式,使用原子力显微镜观测固液界面的纳米气泡,通过浮选试验以及引入六种浮选动力学模型拟合试验数据,研究了纳米气泡对不同粒度级煤泥浮选动力学的影响。试验结果表明,固液界面的纳米气泡呈圆盘状同时具有超大的疏水角,纳米气泡的引入可以使各粒度级煤泥的浮选精煤可燃体回收率得到1%?5%的提高,同时纳米气泡会引起中等粒级精煤灰分的提高以及细粒级精煤灰分的降低。经比较,经典一级动力学模型为最佳浮选动力学模型,各粒度级浮选动力学规律不会因纳米气泡的加入而发生改变。纳米气泡可以使?0.5+0.25 mm粒级的浮选速率常数由2.70增加至4.33,但同时分别会造成?0.25+0.125 mm与?0.125+0.074 mm粒级浮选速率常数15.45%与8.59%的下降,此外,?0.074 mm粒级煤泥的浮选速率在纳米气泡作用下得到13-18%的提高,对于粗、细等难浮煤泥浮选效率与速率的提高是纳米气泡强化煤泥浮选的重要原因。     

强磁性矿粒在磁选过程中的受力分析及动力学模拟

基于磁偶极子磁场分布理论计算强磁性矿粒在磁场中所受到的力,并采用Verlet速度算法对2个磁性矿粒相互作用和9个磁性矿粒相互作用的二维动态过程进行模拟。研究结果表明:磁偶极子力和黏性阻力是影响磁性矿粒团聚的主要因素,磁偶极子力是强磁性矿粒在磁选过程中受到的最主要的力;2个磁性矿粒相互作用的动态过程由外磁场的大小和方向决定,矿粒从初始位置到接触所用时间小于8.3 ms;9个矿粒相互作用的动态过程与初始位置(随机性)有关,矿粒从初始位置到结成磁链所用时间小于30 ms,磁性矿粒最终沿外磁场方向团聚成链状结构。     

基于纳米气泡的煤炭浮选模型研究

为了探讨纳米气泡对煤炭浮选的影响,据众多研究表明,纳米气泡的桥力作用可以促进煤炭颗粒粘结,纳米气泡的气液界面和内部高压可以促进气泡矿化,纳米气泡的低密度可以使煤炭颗粒的沉降速度降低。据此,构建了煤炭颗粒在水中存在的模型及矿化过程模型,并用此模型解释了选药剂、充气量、叶轮转速对浮选效果的影响,得出了基于纳米气泡的影响解释煤炭浮选的规律。     

电浮选过程中气泡行为的研究

为了更好地研究气泡对浮选效果的影响,基于电浮选过程中气泡的特点和特性方程,分析电浮选过程中影响气泡直径的主要因素并确定粒子与气泡的碰撞概率.研究结果表明:在酸性介质中,电极材料对氢气泡直径有明显的影响,中性介质和碱性介质中电极材料对氢气泡直径的影响较小,但介质pH对氧气泡和氢气泡直径均产生较大影响;电极直径和电流密度在所研究的范围内对氢气泡直径和氧气泡直径的影响不大,只是部分气泡直径的分散性变得更加明显;随着温度的增加,最大气泡量所对应的氢气泡直径明显增大,但氢气泡的直径分布范围并未发生太大的改变;随着电流密度的增加,气泡的直径减小,当电流密度达到某一数值时,粒子与气泡碰撞概率达到最大.     

城市再生水中大肠杆菌在浮选过程中迁移规律

通过再生水模拟浮选试验和吸附、解吸附试验分析研究了城市再生水中大肠杆菌在浮选过程中的迁移规律.研究结果表明:再生水中大肠杆菌能够快速被矿物颗粒吸附,尾矿废水继续回用于浮选流程是安全的,但精矿、中矿、尾矿中吸附了大量的大肠杆菌,在特定暴露水平下会对从业人员构成健康风险;矿物颗粒对大肠杆菌的吸附是影响再生水中大肠杆菌在浮选过程迁移的主要因素;随着大肠杆菌浓度的升高,大肠杆菌衰减率、吸附速率随之下降;矿物颗粒对大肠杆菌的吸附对pH变化敏感,随着pH升高,矿物颗粒对大肠杆菌的吸附呈下降趋势,捕收剂煤油、Pj053和调整剂CaO的加入会明显提高矿物颗粒对大肠杆菌的吸附.     

蛇纹石对硼镁石浮选的影响

针对蛇纹石易恶化硼镁石浮选环境的问题,通过浮选试验研究了不同粒度蛇纹石及矿物量配比对硼镁石浮选效果的影响.试验结果表明:浮选过程中蛇纹石与硼镁石颗粒间易发生相互作用,随着矿样中蛇纹石含量增加及蛇纹石粒度减小,硼镁石回收率逐渐下降,并且细粒级蛇纹石对硼镁石回收率影响更为明显,能显著降低硼镁石回收率.结合矿物zeta电位的测定及DLVO理论计算,对溶液中矿物颗粒间作用机理进行了分析,表明矿物表面电性差异是矿物颗粒间相互作用的根本原因.     

Flotation mechanisms of molybdenite fines by neutral oils

The flotation mechanisms of molybdenite fines by neutral oils were investigated through microflotation test,turbidity measurements,infrared spectroscopy,and interfacial interaction calculations.The results of the flotation test show that at pH 2-11,the floatability of molybdenite fines in the presence of transformer oil is markedly better than that in the presence of kerosene and diesel oil.The addition of transformer oil,which enhances the floatability of molybdenite fines,promotes the aggregation of molybdenite particles.Fourier transform infrared measurements illustrate that physical interaction dominates the adsorption mechanism of neutral oil on molybdenite.Interfacial interaction calculations indicate that hydrophobic attraction is the crucial force that acts among the oil collector,water,and molybdenite.Strong hydrophobic attraction between the oily collector and water provides the strong dispersion capability of the collector in water.Furthermore, the dispersion capability of the collector,not the interaction strength between the oily collectors and molybdenite,has a highly significant role in the flotation system of molybdenite fines.Our findings provide insights into the mechanism of molybdenite flotation.     

不同分子结构药剂的煤泥浮选效果

为探究不同分子结构捕收剂对煤泥浮选效果的影响,选取碳原子数均为12、分子结构不同的邻苯二甲酸二乙酯、正十二烷、异十二烷为捕收剂,进行煤泥浮选实验、不同结构药剂与煤泥作用的润湿热测定及红外光谱分析。结果表明:邻苯二甲酸二乙酯浮选的精煤产率、可燃体回收率、浮选完善指标分别比正十二烷高3.20%、3.22%、3.25%,比异十二烷高2.03%、2.05%、2.42%;带苯环的邻苯二甲酸二乙酯的浮选效果最优,依次是异十二烷、正十二烷;含有苯环的邻苯二甲酸二乙酯与煤样作用的润湿热比正、异十二烷高;邻苯二甲酸二乙酯中的苯环更能提高煤表面的疏水性。该研究为新型浮选药剂开发提供了参考。     

用油酸捕收萤石、重晶石和方解石的研究

本文通过试验研究了萤石、重晶石和方解石的可浮性与油酸捕收剂用量及PH值的关系。试验发现浮选萤石、重晶石、方解石所需要的油酸用量不同,次序为:萤石<重晶石<方解石。萤石和重晶石在PH为7左右时可浮性最好,而方解石在强碱性条件下可浮性最好。本文还通过表面电位及清洗试验结果等探讨了油酸捕收萤石、重晶石和方解石的作用机理。     

Effect and mechanism of siderite on reverse flotation of hematite

The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between siderite and quartz are the main reasons that siderite significantly influences the floatability. The interactions are attributed to dissolved siderite species and fine siderite particles. The interaction due to the dissolved species is, however, dominant. Derjaguin-Landau-Verwey-Overbeek (DLVO) theoretical calculations reveal that adhesion on quartz increases when the siderite particle size decreases and that fine particles partly influence quartz floatability. Chemical solution calculations indicate that the dissolved species of siderite might convert the surface of active quartz to CaCO₃ precipitates that can be depressed by starch. The theoretical calculations are in good agreement with the results of adsorption tests and FTIR spectroscopy and explain the reasons why siderite significantly influences reverse flotation of hematite.     

The selective effect of food-grade guar gum on chalcopyrite-monoclinic pyrrhotite separation using mixed aerofloat(CSU11) as collector

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat(CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.     

The selective effect of food-grade guar gum on chalcopyrite-monoclinic pyrrhotite separation using mixed aerofloat (CSU11) as collector

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum (FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat (CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.     

矿浆中金属离子对蓝晶石矿物浮选行为的影响

通过蓝晶石、石英及黑云母的浮选实验,研究了金属离子对矿物浮选行为的影响.实验结果表明:Ca²⁺和Mg²⁺显著活化蓝晶石的浮选,Al³⁺及Fe³⁺对蓝晶石及石英表现很强的抑制作用.浮选溶液化学分析表明,Fe³⁺,Al³⁺可以在矿物表面生成Fe(OH)₃和Al(OH)₃,使矿物浮选受到强烈的抑制;Ca²⁺和Mg²⁺由于羟基络合物存在使蓝晶石的零电点向低pH方向发生漂移,使十二胺的静电吸附力增强,起到活化作用.根据波耳兹曼矢量场中的粒子分布理论,通过计算Fe³⁺对矿物作用前后在不同pH条件下液相内部胺离子(RNH⁺₃)浓度、界面层胺离子的浓度以及比例关系来分析金属离子的活化或抑制作用机理.