The sustained transportation of particles in a suspension commonly results in particle attrition leading to grain size reduction and shape modification. Particle attrition is a well-studied phenomenon that has mainly focussed on sediments produced in aeolian or fluvial environments. Here, we present analogue experiments designed to explore processes of attrition in the kimberlite system; we focus on olivine as it is the most abundant constituent of kimberlite. The attrition experiments on olivine use separate experimental set-ups to approximate two natural environments relevant to kimberlites. Tumbling mill experiments feature a low energy system supporting near continual particle-particle contact and are relevant to re-sedimentation and dispersal processes. Experiments performed in a fluidized particle bed constitute a substantially higher energy environment pertinent to kimberlite ascent and eruption. The run-products of each experiment are analysed for grain size reduction and shape modification and these data are used to elucidate the rates and extents of olivine attrition as a function of time and energy. Lastly, we model the two experimental datasets with an empirical rate equation that describes the production of daughter products (fines) with time. Both datasets approach a fines production limit, or plateau, at long particle residence times; the fluidized system is much more efficient producing a substantially higher fines content and reaches the plateau faster. Our experimental results and models provide a way to forensically examine a wide range of processes relevant to kimberlite on the basis of olivine size and shape properties.
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几种矿物的超细加工及对建材防氡防辐射性能的影响 总被引：3，自引：0，他引：3
采用湿法搅拌磨和气流磨,对用作防氡防辐射基元材料原料的重晶石、沸石进行超细加工和激光粒度分布测试,结果表明：重晶石、沸石通过湿法和干法粉磨加工,在一定的时间内都可以超细粉碎到d90小于10μm,从粉磨时间以及粉磨成本来比较干磨法要明显优于湿磨法;重晶石进行超细加工后所制备的水泥砂浆的外照射指数从0．51降到0．23,重晶石所配腻子的氡和放射性屏蔽率提高20％～30％。当沸石的粒度减小时,水泥砂浆对氡的屏蔽率提高的屏蔽率最大达26％。沸石从119μm降到18μm时,腻子的防氡率从37．9％提高到53．1％。防辐射性能从整体上来看是粒度越细性能越好。 相似文献
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活性白云粉生产工艺及其物化性能研究 总被引：1，自引：0，他引：1
活性白云粉（ABP）是在白云岩经过破碎、细粉碎、表面改性的基础上得到的一种新型改性功能填料。本文利用河南辉县市的拍石头和张村两地产出的白云岩作为实验原料，对其表面改性的实验方法、改性剂选择及用量、改性条件及改性效果等方面进行了一定的探讨，并且对改性前后的白云石粉体的粒度、比表面积等性能及红外光谱特征做了对比研究。生产工艺和物性测试研究表明：活性白云粉代替轻质碳酸钙作橡胶填料前景广阔；与轻钙相比，活性白云粉的粒度不够均匀，经优化和改善生产工艺条件，可望进一步提高其应用价值。 相似文献
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为了使酸性含镍氯化铁蚀刻废液资源化制备的铁黄达到颜料性能指标,通过考察改性剂的种类、改性剂用量、改性p H、改性温度和改性时间对铁黄粉体亲油化度的影响,并通过红外光谱、热分析解析了改性剂在粉体表面作用机理。研究结果表明:在最佳工艺条件下,当改性剂为十二烷基苯磺酸钠、改性剂用量为7%、p H为3.5、温度为30℃和改性时间为30 min时,其亲油化度高达54.7%。红外光谱和热分析显示,十二烷基苯磺酸钠以化学键合的方式结合在纳米铁黄的表面,其包覆量大约为5.4%,使纳米铁黄粉体具有亲油疏水性能。 相似文献
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利用激光粒度仪测试超细煤粉的粒度。对测试超细煤粉试样粒度时的试样浓度、测试温度、分散时间、分散剂的种类及浓度等方面的影响进行了实验研究，给出了激光粒度仪测试超细煤粉粒度的最佳实验条件。 相似文献
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麒麟厂铅锌矿银的工艺矿物学研究 总被引：4，自引：1，他引：4
笔者应用微区测试研究、粒度统计分析及物相分析等，对云南会泽铅锌矿麒麟厂矿床6号矿体铅锌特富矿石中银的工艺矿物特征进行了研究，认为银以类质同象和独立矿物两种状态存在，发现了11种银矿物和含银矿物，方铅矿是银的主要载体矿物，银的最佳回收指标为93．52％－99．20％。 相似文献
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为了改变松散砂土的低强度和低抗侵蚀性,本文以纳米硅材料为基础,采用聚丙烯酰胺类作为改性剂,对松散砂土进行加固研究。分别研究在不同浓度的纳米硅材料以及不同掺量的改性剂的共同作用下,加固松散砂土的无侧限抗压强度、抗剪强度以及其崩解特性的变化规律,并对其加固机理进行分析。试验结果表明,改性后的纳米硅材料对松散砂土的无侧限抗压强度、抗剪强度以及抗崩解能力都得到较大的提高。当纳米硅材料浓度一定时,砂土的抗压强度和抗剪强度随着改性剂掺量的增加出现先增大后减小的趋势;在纳米硅浓度20%、改性剂掺量0.2%时抗压强度达到最大值970 kPa;在纳米硅浓度20%,改性剂掺量0.3%时黏聚力和摩擦角分别为173.2 kPa和39.3°;在加固松散砂土的抗崩解试验中,当纳米硅浓度大于20%、改性剂掺量大于0.1%时,加固后的砂土在水中侵泡8 d后砂样的崩解率低于50%;当纳米硅浓度20%,改性剂掺量0.2%时,加固砂土不崩解。综合试验结果,建议纳米硅溶液的浓度在20%,改性剂的掺量为0.2%作为改性纳米硅材料加固松散砂土的最优配比。 相似文献
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The review is in three main sections. First, the observation that overall flotation performance deteriorates for the finest particles is confirmed, but the precise effects of particle size on recovery, grade, and flotation rate are shown to be more complex. In the second section an assessment is made of theories which have been proposed to explain the slower flotation rate of ultrafines, the effects of slime coating, and the flotation of slimes with cationic collectors. The last section of the paper gives a critical evaluation of methods which are claimed to improve the flotation of ultrafine particles. 相似文献
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福建硬质绢云母表面化学改性的研究 总被引：2，自引：1，他引：2
采用超细粉碎和表面化学改性方法对硬质绢云母进行改性，研究表面改性的机理，建立了一整套的改性工艺，制备出应用性能和价值得到较大提高的改性硬质绢云母超细粉。 相似文献
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改性粘土增强硅橡胶性能的研究 总被引：1，自引：0，他引：1
改性粘土增强硅橡胶性能的研究魏从容吴季怀沈振（华侨大学材料物理化学研究所,泉州３６２０１１）关键词粘土矿物质表面改性硅橡胶增强剂粘土矿物作硅橡胶增强剂是粘土综合开发利用的新课题,我们在这方面取得一定的成果［１］。但是,未经改性处理的粘土其增强能力是有... 相似文献
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D.P. Patil J.R.G. Andrews P.H.T. Uhlherr 《International Journal of Mineral Processing》1997,50(4):289-306
In the shear flocculation process, flocculation of ultrafine (size < 10 μm) hydrophobic particle occurs in the presence of a high shear field. Hence, it is necessary to consider both processes of coalescence and breakage, while modelling shear flocculation.In this paper, a lumped discrete population balance model is presented considering both processes of coalescence and breakage of flocs. A method is also proposed to convert discrete kernels to lumped discrete kernels by satisfying the constraints on them. The numerical solution of the model is compared with some special analytical solutions of the continuous population balance model, with which it is observed to be in agreement. The model equations are derived in such a way that it predicts correctly both the rate of change of number and the total volume of the flocs. The size distribution of a flocculating suspension can be predicted by this model. 相似文献
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Grain‐size data from different climatic zones across the Chinese Loess Plateau show that the loess generally contains an ultrafine component, which has a consistent modal grain size of ca 0·37 μm and a variable proportion of 4 to 10%. The variation of the ultrafine component through a loess section is characterized by a high proportion and fine grain size in palaeosols, and by a low proportion and coarse grain size in loess layers. Its proportional content in a stratum roughly increases from north‐west to south‐east across the Loess Plateau. Quantitative X‐ray diffraction analysis indicates that the ultrafine component is composed mainly of clay minerals (ca 70%), which are mostly illite (ca 80%), and with significant amounts of kaolinite (ca 8%) and chlorite (ca 2%). The temporal and spatial variations of the ultrafine component, and the degree of illite crystallinity, suggest that this component in aeolian sediments is linked closely to the process of pedogenesis. Weakly altered loess on the north‐western margin of the Loess Plateau contains considerable amounts of detrital clay minerals derived from the aeolian source areas. Results from a loess section with a basal age of 7·6 Ma in the central Loess Plateau show that the ultrafine component increased from 7·6 to 5 Ma, and progressively decreased thereafter. This trend was punctuated by two abrupt changes at 2·6 and 0·6 Ma. These variations reflect to a considerable extent the history of pedogenesis during the Late Cenozoic. 相似文献
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There is agreement that ultrafine maghemite grains (<100 nm) are responsible for the magnetic enhancement of Chinese loess. Recent studies show that grain size distribution of ultrafine pedogenic maghemite grains within the aeolian sequences on the central Chinese Loess Plateau deposited in the last 8 Ma is consistent. However, whether the observed grain size distribution of ultrafine pedogenic maghemite grains can be observed in the western Chinese Loess Plateau and modern soils is not entirely clear. Here we find that young surface soil samples across the Chinese Loess Plateau and early Neogene loessic soils from the western Chinese Loess Plateau also show consistent grain size distribution with that of ultrafine pedogenic maghemite grains on the central Chinese Loess Plateau. The fact that young surface soil samples show apparent magnetic enhancement suggests that the ultrafine pedogenic maghemite grains derive from oxidation of ultrafine magnetite grains. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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HELOS/BF型激光粒度仪湿法测试条件的优化 总被引：1，自引：0，他引：1
激光粒度仪以测试速度快、操作方便、重复性好等优点得到越来越广泛的应用,但仪器技术参数和测试条件不同对样品粒度测试结果有着显著影响。本文通过实验得到了HELOS/BF型激光粒度仪的优化测试条件,结果表明:对于比重小或粒径小的样品,采用低搅拌速率、高超声强度和较长超声时间;对于粒径大或比重大的样品,应采用高搅拌速率、低超声强度和较短超声时间。分散剂能加快样品颗粒的分散,且对于粒径小的样品分散效果更好。测试时进样浓度(遮光度)过低,样品中的颗粒数过少,检测不到足够的信号,使样品不具有代表性,样品粒径测定结果偏高;进样浓度过高,出现多重散射而使粒度分布范围较宽,样品粒径测定结果偏低。研究认为,HELOS/BF型激光粒度仪的合适进样浓度为10%～25%。 相似文献
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