哈氏可磨指数不确定度评定

哈氏可磨指数反映了煤的易磨损程度,为评定其合成不确定度和扩展不确定度,将煤样制备成哈氏可磨样品进行测定,测定时分别计算出称量、重复性、曲线变动、有证标准物质带来的不确定度,从而完成合成不确定度和扩展不确定.     

基于矿物结构的高铝黏土矿选择性磨矿分析

通过对我国一水硬铝石-高岭石型高铝黏土中主要矿物的结构与形态及矿石硬度的分析,指出高铝黏土矿含铝矿物和铝硅矿物之间存在可磨性差异。对我国典型高铝黏土矿石进行湿法磨矿及浮选试验表明：湿法磨矿产品中-0．010mm粒级质量分数为38．33％,其铝质量分数比其他各粗粒级产品的铝含量低2～9个百分点;浮选产品中不论是精矿还是尾矿-0．010mm粒级的铝含量较其他各粒级均低3％～6％。说明两种矿物之间确实存在可磨性差异,这种可磨性差异可以作为高铝矾土选矿中磨矿工艺参数选择的基础。     

水渣变化对UM43.6R立磨工况影响及应对

通过分析水渣指标和立磨工况的变化,找出水渣变化对生产的影响因素,提出解决措施：调整水渣堆存和使用、堆焊材料和尺寸、主辊碾磨压力、增加入磨前磁选除铁和增加外排料的筛选等,从而提高了效率、降低了能耗。     

A new approach for the testing method of coal grindability

In this study, a total of 26 hard coal sample (either clean or original) from Zonguldak Coal Basin (17 from Zonguldak, 9 from Amasra) and a total of 17 low grade Turkish coals from various locations in Turkey were collected. So, a total of 69 samples were analyzed initially with standard method of coal grindability, i.e. HGI values were determined. In addition, an alternative method (does not require a standard HGI mill) for grindability measurement was proposed in this study. The abovementioned alternative method includes a ring mill with specified conditions and Malvern Mastersizer. As regards to the procedure of the new proposed method for the determination of coal grindability, samples were prepared in the size range of −1.7 + 1.18 mm size group and they were ground in ring mill. Here, ring mill was chosen because of the fact that it is very widely used for sample preparation and it is very commonly available in every laboratory. Procedure proposed includes placing abovementioned specified samples in ring mill (See Material and Method) and having the samples ground in a previously determined time period. After this grinding process (with ring mill) they have rather different size distribution at the end depending on their nature of grindability. For better understanding, having the ground samples of (−1.7 + 1.18 size group for 20 s for 50 g samples) and analyzing their size distributions with Malvern Mastersizer, ground samples have different D₁₀, D₅₀, D₉₀, D₃₂ and D₄₃ at the end. Comparing these size parameter results with previously determined HGI values, it can be claimed that coal grindability can be easily determined with this method, since evaluated HGI values with the method proposed are ±0.05% different than the determined HGI values.     

Study of Iron Ore Mixtures Behavior in the Grinding Pelletizing Process

The main unit operations of pelletizing process are grinding, filtering, pressing, pelletizing, and firing. Grinding, the first operation in the process, is a crucial step for the subsequent operations. Three iron ore mixtures with different grindability index (low, medium, and high) were used in order to verify the influence in the operational parameters such as production rate, discharge density, and pump pressure. Through Design of Experiments (DOE), nine experiments over each iron ore mixture were done, varying the minimum and maximum grinding operational parameters. Independent variables (responses) were the specific surface area or Blaine index (BI) and the particle size (PS), which were measured by the automatic PS analyzer system (PSI). The main objectives of this study are to know the behavior of iron ore mixtures with different grindability indexes in the industrial plant and develop a regression model that can be used for real-time measurement of PS and BI for different grindability indexes in the industrial operations. The results showed satisfactory correlations between the factors and responses.     

高性能难加工材料可磨削性研究进展

高性能难加工材料在高端制造业中的应用越来越广泛,关键零部件的精度要求极高,而材料的可磨削性差,对磨削加工工艺提出了严峻挑战.为了提高难加工材料磨削表面完整性,降低砂轮磨损,国内外学者开展了大量研究.全面回顾了难加工金属材料、硬脆材料以及复合材料可磨削性的国内外研究进展,包括工件表面完整性、砂轮堵塞与磨损、磨削颤振以及改...     

石油焦焦质特性对水焦浆稳定性影响的实验研究

为了优化水焦浆的稳定性,实验研究了4种石油焦成浆的静态稳定性,分析了石油焦的可磨性、表面电性和孔隙结构对水焦浆稳定性的影响规律。实验结果表明:4种不同的石油焦,在同等条件下制备水焦浆,静置7 d后,水焦浆在硬沉淀产生量和析水产生量方面呈现较大差异,浆体稳定性悬殊。不同石油焦的可磨性不同,致使各焦粉的粒度分布特征有异,焦粉粒度分布峰高且窄、粒径集中时,颗粒堆积效率低,浆体稳定性差;粒度分布峰扁平且宽、粒径均匀时,不同粒度级间能够达到较好的填充效果,颗粒堆积效率高,成浆浓度高,浆体稳定性好。石油焦颗粒表面荷电量也各不相同,焦粒Zeta电位绝对值越大,焦粒间的静电排斥力越强,越能有效的阻碍颗粒间的凝聚,从而使颗粒在浆体体系中得以稳定分散,使浆体呈现较好的静态稳定性。石油焦微观孔隙结构特征与水焦浆的稳定性之间存在一定的内在联系,石油焦比表面积越小、平均孔径越大,水焦浆的稳定性就越好。     

高炉喷吹用煤粉的可磨性试验研究

对4种高炉喷吹用煤(晋城北、冬田良、青州和邯郸)进行了煤岩显微分析和工业分析,并且对各单煤的可磨性指数进行了测定,研究了磨煤温度对不同煤化程度单煤的哈氏可磨性指数的影响以及不同煤种混合煤的可磨性。试验结果表明,4种煤中冬田良煤含硫量以及青州和邯郸2种煤的灰分略高于指标要求,其他指标均可以满足喷吹用煤的指标要求;不同煤种单煤的可磨性指数相差较大,晋城北无烟煤的可磨性指数最低,不符合喷吹指标,需进行配煤提高其可磨性;随着磨煤温度的升高,不同煤化程度单煤的可磨性指数均有一些增加,对煤化程度较高的无烟煤的影响较小;不同煤种混合后煤样的可磨性指数并不等于各单一煤种的可磨性指数的加权平均值。     

酒钢两种粉矿矿石性质及可选性对比试验研究

酒钢镜铁山铁矿分为桦树沟和黑沟两大矿区,前者为井下矿,后者为露天矿,两者的矿物组成、结构构造及选矿参数均有较大差异,但却进入相同的工艺,采用相同的参数进行选别,造成生产技术指标不是最佳。通过对两种粉矿的矿石性质及可选性进行对比研究,查明其差异,并确定各自适宜的磨矿、选别等工艺参数,为进一步改善精矿质量、提高资源利用率提供依据。     

高炉喷吹用煤的可磨性研究

在对高炉喷吹用煤和兰炭进行工业分析的基础上,对不同比例兰炭与煤混合试样的可磨性分别进行了测试分析。结果表明,试验用煤和兰炭的水分含量均高于喷吹用煤指标要求,可磨性指数普遍偏低,其中高挥发分烟煤的可磨性最低,不符合喷吹用煤要求。