碱金属在白云鄂博铁精矿还原中的催化作用研究

利用失重法对碳的气化反应、CO气体以及碳还原白云鄂博铁精矿进行了实验,使用矿相、XRD分析了还原后样品的相组成与显微结构。研究结果表明：加入催化剂后,碳的气化反应速率和铁精矿还原速率提高,且K2CO3和Na2CO3的催化效果明显优于CaCO3的催化效果。催化剂的加入有助于碳的活性提高,加速了碳的气化反应,从而促进了白云鄂博铁精矿还原反应进行。     

Kinetics study of leaching arsenic from Ni-Mo ore roasting in dust mixture of hydrochloric and sulfuric acids

The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated. The effects including leaching temperature, particle size of the smelter dust, stirring speed, the coefficient β（the molar ratio of sodium chlorate to arsenic in the smelter dust） and the initial H＋ concentration on leaching arsenic were studied. The results indicate that the leaching of arsenic increases sharply with the decrease of particle size. The orders of reaction with respect to H＋ concentration and particle size are determinted to be 1.136 and 1.806, respectively. The leaching of arsenic reaches 99% under experimental conditions, the apparent activation energy is determined to be 11.157 kJ/mol, which is consistent with the values of activation energy for diffusion model The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η （1 -η）^2/3 = k0（c[H＋]）^1.136ro^-1.806 exp[（-11157 /RT）t].     

304不锈钢GTAW背面保护焊剂性能研究

为了研究单面焊接双面成形背面保护剂的保护效果,采用光学显微镜、电子显微镜、能谱仪、显微硬度计等对接头组织及性能进行表征和分析。结果表明,采用Solar TYPE B型焊接保护剂可以获得成形良好的焊缝;熔合线附近的焊缝组织为联生结晶的奥氏体柱状晶,焊缝中心组织为细小均布的奥氏体枝晶,平均枝晶间距为8.9μm;焊缝背部表层有较低含量的O元素,从而说明保护剂对焊缝背部的保护具有效果良好;焊接接头热影响区的硬度较低,而焊缝区硬度较高,但总体硬度值波动不大。     

Low-temperature phase formation in the SrF2–LaF3 system

Phase formation in the SrF₂–LaF₃ system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF₃ in SrF₂ decreases with decreasing temperature. The equilibrium width of the solid solution region Sr_1−xLa_xF_2+x at 400°C, it is 44.6 ± 0.4 mol% LaF₃ (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF₃ (x = 0.383), and decreases almost to zero at 300°C.     

一种新型的缓倾斜多层矿体采矿技术

针对传统缓倾斜多层矿体的采矿方法 ,如全面法、中深孔落矿下盘漏斗法和爆力运搬法等 ,生产能力小、劳动强度大、安全性差、成本高等缺点 ,从云南锡业公司松树脚锡矿“大马芦”矿段的实际开采技术条件出发 ,提出了一种新型颇有特色的缓倾斜多层矿体的采矿方法———深孔合采井下矿废分离连续采矿法。它采用大直径深孔合采矿岩、井下矿岩集中分离、连续采矿等技术 ,变革了传统的分采工艺 ,有效地克服了传统采矿方法的弊端 ,为缓倾斜多层矿体的高效、低耗和安全开采提供了新的技术方案。     

焊接工艺对2205双相不锈钢焊接接头综合性能的影响

采用等离子弧焊打底 TIG焊盖面及等离子弧焊打底 MIG焊盖面焊接工艺焊接了2205双相不锈钢,研究了2205双相不锈钢的焊接性,并对焊后固溶处理与未进行固溶处理的焊件组织特征、力学性能及抗腐蚀性进行了比较,研究了不同焊接热输入和固溶处理工艺对焊接接头综合性能的影响.     

碳基钨涂层在退火过程中的组织和结构变化

用真空等离子体喷涂(VPS)技术在C／C复合材料基体上制备了厚度为0．5mm的钨(W)涂层，涂层的表面通过物理气相沉积(PVD)预沉积钨、铼(Re)多层作为碳(C)的扩散势垒。涂层经过1200℃--2000℃的电子束退火，其微观结构和化学构成发生变化。经测量涂层的再结晶温度约为1400℃，再结晶的活性能为63kJ／mol。当退火温度高于1300℃时，涂层表面的多层W、Re结构将由于W、Re和C之间的相互扩散而发生改变，并在1600℃以上退火lh后由于脆性碳化钨在界面的形成而完全失效，碳化钨层的厚度将随着退火漏度的升高和退火时间的延长而迅速增加。     

A scanning tunneling microscopy tip with a stable atomic structure

A single stable adatom on a {110}-type plane of a tungsten tip is created via field-evaporation in a field-ion microscope (FIM) operating at room temperature. This single adatom has sufficient surface mobility at room temperature and migrates, in one-dimension, along a <111>-type direction toward an edge of a {110}-type plane, due to the existence of an electric field gradient. The plane edge has a higher local electric field than its center, since it has a higher local geometric curvature. This result implies that the stable position of a single adatom during a scan of a scanning tunneling microscope (STM) tip on a surface is at the edge and not at the center of a {110}-type plane at room temperature. Therefore, the electron wave function of a tip is not symmetric and this fact should be taken into account in a careful analysis of STM images. Also a tip with a dislocation emerging at a {110}-type plane is suggested as an improved STM tip configuration, as the step at the surface, created by the intersection of the dislocation with it, is a perpetual source of single adatoms.     

几种提高微晶石锯片综合应用性能的方法

近年来，微晶石作为新型的装饰材料在我国获得了广泛的应用。针对微晶石的难加工与锯切，从在金刚石刀头胎体中添加钨粉、采用制粒工艺以及设计多层结构刀头三方面探讨提高微晶石锯片的综合应用性能。结果表明：钨粉的添加能改善金刚石刀头的性能并提高锯片的寿命；制粒技术的应用可改善金刚石在胎体中的均匀分布和提高对金刚石的把持力；多层结构刀头有效提高了锯片的锋利度和切削质量。     

云锡塘子凹矿体矿岩物理力学参数研究

通过对 31- 1#矿体矿岩物理力学参数的研究 ,对矿岩特性及稳固性进行了科学、合理地评价 ,为矿体开采过程中采矿方法的选择、采场结构参数的确定及回采过程中 ,地压的管理提供了科学依据 ,从而保证了矿山生产的安全可靠性