行星磨中物料填充率对水泥熟料破碎参数的影响

为了评估行星磨的粉磨效率,对卧式行星磨中物料填充率对水泥熟料的破碎速率和初始破碎分布函数进行研究。实验所用的物料填充率为0.07、0.08、0.09、0.10、0.12,物料为>2.36~3.35、>2.0~2.36 mm粒级的水泥熟料,对不同物料填充率下的破碎速率进行比较。结果表明,不同物料填充率下对水泥熟料进行粉磨遵循一级粉磨动力学方程,两个粒级的物料破碎速率都是在填充率为0.10时最大,此时的粉磨速率最快;初步研究认为物料填充率对初始破碎分布参数影响较大;>2.36~3.35 mm粒度的物料填充率为0.07时曲线下半段的斜率最小,下半段的截距和上半段的斜率在物料填充率为0.12时达到最大值;2.0~2.36 mm粒度的物料填充率为0.09时曲线下半段的斜率最小,下半段的截距和上半段的斜率在物料填充率为0.12时达到最大值。     

Estimation of the Bond Grindability Index From the Sink-Float Test Data of Two Different Particulate Pumices

In this study, equations for estimating the Bond grindability index by the sink-float test data of pumice were developed. Primarily, the cumulative weight and porosity content of the floating fraction were determined for two different pumice samples in all relative densities. Then, grindability of the pumice samples was determined for its constituent specific gravity fractions. Though the grindability of the constituent specific gravity fractions of both the pumices varies in a systematic manner, certain differences, it can be observed in the variation pattern between the two pumices. These differences included easy washability and moderate difficult washability characteristic pumices. The relationships between the Bond grindability and relative densities and between the Bond grindability and porosity were stated as simple equations, and the calculated values from equations were compared with the experimental results. Finally, the float–sink test results can be stated by simple equations relating to the Bond grindability value. The Bond grindability (G_bg) was easily measured by carrying out sink-float tests, and by measuring the constituent relative density fractions and porosity content.     

研磨体形状对水泥熟料破碎参数的影响

为探讨研磨体形状对破碎参数的影响,采用钢球和钢段两种形状研磨体对水泥熟料进行粉磨,通过对粉磨产物的筛分处理,分析其粒度分布情况,研究粉磨过程中粉磨动力学方程的表述形式,最后运用非线性拟合技术进行回归分析。结果表明:采用上述两种形状研磨体,水泥熟料的粉磨均遵循一级粉磨动力学方程。钢段的破碎速率高于钢球的破碎速率,钢段粉磨物料可以在较短时间内达到预定细度。进一步研究证实:破碎分布函数基本不受研磨体形状的影响,与进料粒度有关。     

酸洗-冷轧联合机组闪光焊接头断带原因分析

采用宏观分析、力学性能测试、金相检验和断口分析等手段对某酸洗-冷轧机组闪光焊低碳Stb35L钢薄板接头在冷轧过程中频繁出现断带的原因进行了分析。结果表明:闪光焊接头发生开裂和断带的主要原因是其热轧原料钢板的头尾板形较差,而闪光焊前又未对其进行校平或剪切,从而导致接头局部出现焊缝搭接错边现象;在冷轧过程中,焊缝搭接处产生折叠和缺口裂纹,裂纹不断扩展最终导致断带;另焊缝中存在未挤压干净的链状氧化物是导致接头开裂和断带的另一个原因。     

Dry Comminution of Silicon Carbide Particles in a Fluidized Bed Opposed Jet Mill: Kinetics of Batch Grinding

This study investigated the batch grinding kinetics of silicon carbide (SiC) particles in a fluidized bed opposed jet mill by population balance modeling. The selection and breakage functions were obtained by the first Kapur function method. The breakage behaviors for various SiC particles obtained under different experimental conditions (such as inlet air pressure, feed load, and distance between nozzle outlet and jet meeting point) in the jet mill were discussed. In addition, a polynomial model was proposed to predict the relation between the Kapur function and the particle size in the jet mill. The product size distributions obtained under various operating conditions from the jet mill could be simulated by modeling.     

低品位铝土矿在振动磨机中的选择性磨矿研究

以氧化铝与氧化硅的质量比为4.4的铝土矿为研究对象,采用振动磨机对铝土矿进行了选择性磨矿试验研究。结果表明:磨矿浓度为70%(质量分数)时,磨矿产品粗粒级的氧化铝与氧化硅的质量比较高,选择性较好;料球比为0.9时,其选择性磨矿效果较好;湿式磨矿较干式磨矿的选择性效果更好;在此最适宜条件下,磨矿产品中大于0.23mm的粗粒级氧化铝与氧化硅的质量比可达到7.5以上,产率为25%,Al2O3回收率为27%,说明对低品位铝土矿选择性粉碎脱硅是可行的。     

立磨选粉机操作参数对分级流场影响的数值模拟

采用离散相流体模型和RNG k-ε湍流模型,对涡轮式立磨选粉机内的气-固两相流场进行数值模拟,对比分析不同操作参数下的速度场、压力场和设备分级效率,获得转笼转速和系统风量对选粉机分级流场的影响规律,并进行相关的试验研究。结果表明,较低的转笼转速和过大的系统风量均会引起叶片间退行面处正漩涡的产生;转笼转速过高或系统风量较小时,分级叶片间的进入面处会出现反漩涡。正、反漩涡的产生均加剧了分级叶片间的速度波动,严重影响了分级流场的稳定性,同时也导致选粉机循环负荷的增加。综合数值模拟与试验分析,系统风量为5 500 m3/min与转笼转速为55 r/min是SMG5500型立磨选粉机的最佳参数匹配。     

卧式行星磨粉磨水泥熟料的最佳参数研究

采用自行设计的卧式行星球磨机,在公转转速为300 r/min、自转与公转转速比为2.5的条件下,研究装球率、料球体积比、填充率对水泥熟料粉磨的影响。结果表明:成品粉体产率随装球率的增大呈增加趋势,在装球率为6.00%～10.51%时尤为明显,装球率大于10.51%时,增加趋势开始变缓;在固定填充率下,料球体积比为0.5时,成品粉体产率最大为65.80%;料球体积比为0.5,总填充率为35%时,成品粉体产率最大为68.56%。     

Effect of Various Operating Factors on Wet Stirred Mill Performance

In this study, the effects of various operating factors, such as initial particle size, feed quantity, filling volume of the ball, and ball size distribution on fine grinding of calcite powders (CaCO₃) were studied using a laboratory stirred mill under wet conditions. A series of laboratory experiments using 2⁴ full factorial designs was conducted to determine the optimum grinding parameters. The main and interaction effects on the specific surface area (m²/g) of the ground product were evaluated using Yates' analysis. The test results showed that the main factors that influence the mill grinding performance are the feed quantity and the ball size distribution.     

衬板对卧式行星磨粉磨水泥熟料的影响

采用自行设计的卧式行星球磨机,研究衬板厚度、粉磨时间、公转转速等因素对水泥熟料粉磨的影响。结果表明:3 mm厚度衬板对实验所用卧式行星球磨机粉磨水泥熟料最有利;使用3 mm厚度衬板、离心加速度为14G、粉磨5 min时效果最好,此时成品粉体产率可达66.62%;使用3、5、7 mm厚度衬板时,临界自转与公转转速比分别为2.5、2.0、2.0。     

矿物颗粒形状对球磨机磨矿性能的影响

为了探究矿物颗粒形状对球磨机研磨作业的影响机制,运用离散单元法,采用球体和由球形颗粒凝聚而成的正四面体、平行六面体矿物颗粒模型,数值模拟球磨机的磨矿过程,分析矿物颗粒形状对运动形式、碰撞形式以及球磨机磨矿性能的影响。结果表明,矿物颗粒形状对球磨机磨矿性能的影响很大,相同条件下,球形矿粒碰撞能最大,正四面体矿粒次之,平行六面体矿粒最小。     

憎水剂对钢铁表面不同涂层破损处的修复行为研究

飞机部件在组装、运输等过程中易造成表面涂层的破损划伤,一些零部件的连接形成的缝隙等都是环境介质侵蚀的通道和发生腐蚀的敏感区域。为此以环氧有机硅涂层、聚氨酯涂层、AV15涂层(国外产品)为基础,用航空零件用憎水剂(BH-102)对涂层破损划伤处进行修复,考察了修复后的涂层在中性盐雾、湿热环境中的腐蚀特性。结果表明:憎水剂在这三种涂层的破损划伤处修复都能得到具有明显憎水效果的表面膜层,可以有效抑制破损划伤处的腐蚀过程;相比憎水剂对环氧有机硅涂层、聚氨酯涂层破损处的修复来说,憎水剂对AV15涂层的修复效果(防腐蚀性能)优异是因为憎水剂与这种涂层中的成膜物和阻蚀成分产生协同作用的缘故。     

纳米粉体超细纳米研磨技术交流

纳米科技是21世纪科技发展的重要技术领域,纳米科技将创造另一波技术创新及产业革命。其应用领域非常广,遍及电子、光电、医药生化、化纤、建材、金属及各基础产业。不论其应用领域为何,所需要用的材料均为次微米或纳米级尺度材料。如何得到纳米级粉体及将纳米级材料分散到其最终产品已成为目前产业、经济及学术界共同的研究课题。文章针对如何得到纳米粉体研磨及将纳米材料分散到其最终产品等技术进行探讨。     

高能球磨法制备铁、钨金属微粉的研究

用高能机械球磨法制备了金属铁、钨微粉，对振动磨的结构及破碎原理作了简要介绍，分析了铁、钨粉末产品的粒度分布特性、比表面积变化情况，讨论了原料性质、球磨时间、球磨强度、球料比等因素对高能球磨过程的影响。     

KHM170型卧辊磨制备钢渣超细粉工业试验研究

基于KHM170型卧辊磨的钢渣超细粉制备终粉磨工业试验系统,在给定钢渣粉、矿渣粉、水泥熟料粉的质量和粒度范围内,进行用钢渣粉部分代替矿渣粉制作水泥混凝土的强度试验。结果表明,KHM卧辊磨终粉磨系统可以实现钢渣超细粉终粉磨,可用于以热焖渣、滚筒渣为原料制备钢渣微粉的工业化生产;矿渣粉中掺加质量分数不超过30%的钢渣粉,且在满足钢渣粉比表面积大于矿渣粉比表面积和水泥熟料粉比表面积时,可以作为优选的混合材料大量用于混凝土。     

高速动车组噪声测试及其声品质客观参量分析

在高速动车组减振降噪设计中,声品质已成为舒适性评价的重要指标之一。以Zwicker提出的对噪声进行主观评价的客观量化方法为基础,通过响度、尖锐度、粗糙度和抖动强度4种噪声客观评价参量计算方法对某高速铁路动车组车内噪声试验测试数据进行分析,得到车内典型位置不同运行速度时各心理声学参量的现状和分布规律,可为高速铁路动车组车内声品质研究提供参考依据。     

气流磨生产过程中喂料速率对粒度的影响

为在流化床式气流磨进行生产时合理选择喂料速率,以获得较好的产品,通过小型气流磨加工滑石粉实验,分析不同分级轮转速下磨腔料位、产品中位径与喂料速率之间的关系,以及喂料速率对产品粒度的影响。结果表明,提高分级轮转速,可以很明显地减小产品中位径;当物料粉碎过程进入稳定状态以后,分级轮的每一个转速都对应一个喂料速率的临界值,在一定的分级轮转速下,把喂料速率调整到最佳值,可以获得粒度更细、分布更窄的产品;喂料速度控制不好将引起分级轮电机过载,产品粒度不稳定,设备产能降低。     

助磨剂对煅烧高岭土在振动磨中粉体流动度的影响

为解决用振动磨进行煅烧高岭土的细磨过程中常出现磨机出料困难的问题,采用实验室的振动磨进行粉体流动度实验,通过添加不同种类和用量的助磨剂改善振动磨粉体的流动度,以改善振动磨内粉体的研磨效果。结果表明,煅烧高岭土的最佳研磨时间为40 min左右,当研磨时间超过40 min时,产品的颗粒粒度不会变得更细;加入助磨剂后,粉体在振动磨中的流动度得到改善,同时也能使产品的细度得到有效调整;有机助磨剂对流动度的影响明显好于无机助磨剂,但助磨剂的用量必须控制在合适的范围才能使流动度达到最佳指标;有机助磨剂用量在0.50%时流动度最好,无机助磨剂用量在0.10%时流动度最好。     

Influence of high-pressure grinding rolls on physical properties and impact breakage behavior of coarsely sized cement clinker

ABSTRACT

High-pressure grinding rolls (HPGR) are widely used in cement clinker grinding prior to ball milling. The efficiency of HPGR was previously related to two capabilities: (a) efficient stressing mechanism and (b) weakening of particles which lead to finer product sizes after subsequent ball milling. This study aimed to investigate the influence of HPGR on the impact breakage behavior of coarsely sized cement clinker. Drop weight tests were conducted on three single-size samples from both feed and product streams of an industrial HPGR, so as to obtain impact breakage parameters: breakage probability and impact breakage functions. Radiographic, Vickers micro-hardness, BET, SEM, XRD, XRF, and image processing methods were utilized to explain the variations in impact breakage parameters. The product samples were found to have less porosity than feed samples but they contained HPGR-induced micro-cracks. Those cracks are believed to be responsible for lower hardness and higher breakage probability of product particles than of feed ones under impact. However, fragments generated from the product samples by drop weight tests were coarser than those generated from feed samples. That was due to elimination of pores by HPGR action. At excess energy levels, both samples were broken to same extent regardless of structural differences.