Some breakage characteristics of ultra-fine wet grinding with a centrifugal mill

A centrifugal mill is a high-power intensity media mill that can be used for ultra-fine grinding, employing centrifugal forces generated by gyration of the axis of the mill tube in a circle. The mill charge motion is quite different depending on the ratio of the gyration diameter to the mill diameter (G / D ratio), varying from a motion similar to that of a conventional tumbling media mill to that of a vibration mill. In this study, a centrifugal mill was constructed with an arrangement where the gyration diameter could be readily adjusted. The batch grinding characteristics of three different minerals (limestone, talc and illite) in water with dispersing agent were investigated at various G / D ratios. It was found that the optimum G / D ratio in terms of the specific energy consumption to give a desired fineness of product was different for the three minerals. This was due to their different reactions to the breakage mechanisms provided by the mill charge motion at varying G / D ratios. The size distributions became progressively narrower at increased grinding times, and particles finer than about 0.1 μm were not detected even for prolonged grinding times. Measurement of specific surface areas indicated that this was not due to an artifact of the size measurements by laser diffractometry. This implies that there is a limitation in which particles finer than 0.1 μm are not produced under the conditions tested in this type of mill, but further investigation is needed for experimental verification of this limit of comminution.     

Modeling of the classification behavior of the diaphragms used in multi-chamber cement mills

A new approach has been developed for describing the classification that arises at the diaphragm in multi-chamber ball mills. Fourteen industrial scale cement mills have been sampled in this study and after mass balancing, model fits of the equipment were done. Successive mill product predictions for the sampled conditions were achieved, and requirements to build up an optimization capable model are discussed.     

A Solution to the Problem of Predicting the Suitability of Silty–clayey Materials for Cement-stabilization

Major geotechnical problems in construction involving silty–clayey soils are due to their low strength, durability and high compressibility of soft soils, and the swell–shrink nature of the overconsolidated swelling soils. Confronted with these problems, a suitable ground improvement technique is needed, for deep excavations in soft clays, for stability, durability and deformation control. Cement-stabilization is one of the alternatives. An increase in strength and durability, reduction in deformability are the main aims of this method. Conventional cement-stabilization methods are used mainly for surface treatment. However, the use of cement has recently been extended to a greater depth in which cement columns were installed to act as a type of soil reinforcement (deep cement–soil mixing and cement jet grouting). In situ engineering properties of these silty–clayey soils are often variable and difficult to predict. For this reason cement-stabilization methods have a basic target to control the aforementioned engineering properties of these clays so that the properties of a silty–clayey soil become more like the properties of a soft rock such as clayey shale or lightly cemented sandstone. So cement-stabilization of these soils is essential to control their engineering properties and to predict their engineering behaviour for construction. In an effort to predict, classify and study the suitability of silty–clayey soils for cement-stabilization both slaking and unconfined compressive strength tests were carried out on clayey–sand mixtures consisted of two types of clays, kaolin and bentonite. Finally diagrams were prepared to study the variation of slaking and strength due to compaction, curing time and cement percentage and also to predict areas of efficient cement-stabilization.     

机械研磨对平鲁煤系高岭石热行为的影响

对煤系高岭石进行0-2h的研磨之后，再在900℃、1000℃、1400℃的温度条件下分别对其加热1h，然后利用X射线衍射（XRD）、差热分析（DTA）、红外光谱（IR）等手段，研究机械研磨对于煤系高岭石晶体结构的破坏作用以及对其热行为的影响。结果显示，煤系高岭石被研磨1h之后，高岭石的晶体结构几乎全部跨塌。把研磨1h的煤系高岭石加热到1000℃（加热1h），便能形成结晶良好的莫来石。     

“96.8”特大暴雨的中尺度对流云团特征

１９９６年８月３－５日河北省的西南部地区出现了特大暴雨过程。此次特大暴雨，主要是８６０８号台风登陆后减弱为低气压西北上，副热带高压加强西进，低层从东北部有弱冷空气扩散南下，在暴雨区域形成湿斜压锋区，触发不稳定能量释放，致使台我低压北方形成３个中尺度对流云团所致。     

柏井采空区地基注浆加固技术

通过目前国内外现有资料的对比研究，对严重影响石太高速公路修建和运营的柏井采空区采用压力注浆的方法，充填采空区上覆的裂隙冒落带，以达到加固地基的目的。灌注材料选用水泥和粘土，水固比为１：１．５，依据地面构造物不同，在桥涵地段采用１：０．８：０．７（水：水泥：粘土，下同）的配比，在边坡地段采用１：０．５：１的与比，在一般路段采用１：０．３：１的配比，灌注浆液的结石体在采空区及上覆的裂隙冒落带中充填率达     

钙膨润土钠化技术

利用我国丰富的钙膨润土资源，人工改性和为钠膨润土，钠化原理是利用膨润土中主要矿物成分蒙脱石晶层表面吸附性能，在水存在的条件下进行盐基交换反应。泥浆性能全部达到天然优质钠膨润土的指标，完全符合国际通用ＡＰＩ标准。     

中国东部6区域近1000年干湿序列的重建和气候跃变分析

本文利用我国的历史气候记载，为东部6区域重建了最近1033年的时间分辨率为1年的区域于湿气候序列，讨论其可靠性，并分析其变化的准周期性和跃变特征。跃变分析采用移动t检验方法，分析各区域干湿气候的世纪尺度和10～20年尺度的跃变现象，辨识跃变信号的参考年代，指出北方各区域的跃变趋势相同，但有时与长江下游地区相反，以及跃变信号在寒冷气候背景下较多出现等特点。     

立方氮化硼的应用与机械加工的技术进步

立方氮化硼内其具有“三高”特性，而成为一种理想的硬磨料得以发展，着重介绍了立方氮化硼磨具和刀具及其推广应用，并阐述其技术的发展对机械加工技术的进步具有重要的意义。     

Discovery and analysis of ultra-micro grinding grain texture in slipping lamellae of ductile-brittle zone

In the 1990s of the 20th century, we participated in the research of the stress field in fissure tectonics of scientific deep bore cores for the Deep Observation and Sampling of the Earths Continental Crust (DOSECC for short). Spherical and enriched ul-tra-micro granular textures (nm size), which enriches Nb element (Wang & Sun, 1990; Sun & Wang, 1993)[1,2], were found during the observation of ul-tra-micro slipping lamellae of ductile and brittle oc-curring in Late Mesozoic granites us…