The physiochemical effect on the microcutting of pure copper is studied through characterization on the cross-sectioned microgroove. An obvious reduction in cutting force and thrust force can be obtained with the application of ink surfactant. The surface roughness of microgroove with physiochemical effect is 12 nm, and that without physiochemical effect is 17 nm. The average grain size of the ink-affected sample is 67.9 µm within the microgroove zone, and that of the ink-free sample is 48.3 µm within the microgroove zone, moreover, the grain size of ink-free microgroove near the microgroove surface is larger than that far away from the microgroove surface. Additionally, the grain orientations of ink-affected cross-sectioned surface present anisotropy, while that of ink-free cross-sectioned surface are towards {101} direction. Based on the calculation and analysis of geometrically necessary dislocation, it can be inferred that the induced stress and temperature in the sample with physiochemical effect are higher than that without physiochemical effect, which can provide enough driving energy for recrystallization.
不锈钢渣中铬赋存在尖晶石相中,可防止Cr6+浸出.将不锈钢中重金属Cr选择性富集、稳定化,有利于提高不锈钢渣综合利用率.本文基于熔渣非平衡凝固理论,研究了碱度、MgO及FeO含量对CaO-SiO2-MgO-Al2O3-FeO-Cr2O3不锈钢渣体系凝固过程中尖晶石相析出温度、析出量及化学组成的影响.计算结果表明:CaO-SiO2-MgO-Al2O3-FeO-Cr2O3 渣析出相主要有Ca2SiO4、Ca2MgSi2O7、Ca2Al2SiO7、尖晶石相等.MgCr2O4尖晶石析出量随碱度增加而逐渐增大,提高碱度可抑制FeCr2O4析出.当温度降低至1 000℃,MgO含量为8％～12％时,渣中MgCr2O4尖晶石析出量最大,FeCr2O4尖晶石析出量随MgO含量的增加而降低.随着FeO含量升高,MgCr2O4尖晶石析出量降低,FeCr2O4尖晶石析出量增加,FeO不利于Cr在MgCr2O4尖晶石相中的富集.不锈钢渣中含铬尖晶石相析出的实验结果验证了热力学计算结果,碱度为1.5时,不锈钢渣中铬在尖晶石相中的富集率约为93％.
采用循环伏安、线性伏安、电化学阻抗谱等分析测试手段并结合电解实验,系统地研究了硫酸体系下Mn2+的电化学氧化行为.结果表明,Mn2+ → MnO2的电氧化过程存在钝化现象,为实现MnO2的高效电解,需合理控制阳极电位,从而避免析氧和生成MnO4‒.升高电解温度可有效改善电解MnO2过程的界面钝化;通过控制合理的阳极电流可获得更高的电流效率.在50 g/L H2SO4 + 25 g/L Mn2+电解液中,80℃下,当阳极电流密度为6 mA/cm2时,电流效率可达到96.6%.
搅拌桨叶层数对导流筒搅拌槽的搅拌特性有着极其重要的影响.以赣南某稀土企业容积为10 m3的导流筒搅拌槽实物模型数据为参考,利用Solidworks三维软件建立了导流筒搅拌槽及不同搅拌桨叶层数的三维模型.运用流体软件Fluent对其进行网格等数据处理,然后根据相关公式选取桨叶层间距450 mm为基础数据,以相近性原则选取甘油水溶液为载体,对料液在不同搅拌桨叶层数的导流筒搅拌槽中的混合过程进行仿真模拟.以时均速度分布、速度、湍流动能和功率消耗等参数作为评价依据,选不同桨叶层数的导流筒搅拌槽的搅拌特性进行分析评价,验证了双层搅拌桨叶的导流筒搅拌槽的搅拌特性较好.
为掌握磁黄铁矿成分对黄铁矿粉尘爆炸的影响,在20 L爆炸球及粉尘云最低着火温度测试装置中,评价了磁黄铁矿对矿山采集的原生黄铁矿(简称原矿)、黄铁矿纯矿物的最大爆炸压力、最大爆炸压力上升速率、爆炸下限浓度、粉尘云最低着火温度4种爆炸特性参数的影响;结合爆炸产物成分与表面结构测定结果,分析了磁黄铁矿影响黄铁矿粉尘爆炸化学反应机理.结果表明:磁黄铁矿成分可以提高氧气与原矿中黄铁矿颗粒发生化学反应的概率,降低黄铁矿粉尘云最低着火温度和爆炸下限浓度,进而提高黄铁矿粉尘云最大爆炸压力和爆温.黄铁矿、磁黄铁矿粉尘爆炸产物受爆温控制,最终产物为磁铁矿Fe3O4及SO2.爆炸反应过程符合缩核—含挥发分的颗粒燃烧模型.
