Molecular Dynamics Simulations of Dislocation Activity in Single-Crystal and Nanocrystalline Copper Doped with Antimony

Recent experimental and simulation results have indicated that high-temperature grain growth in nanocrystalline (NC) materials can be suppressed by introducing dopant atoms at the grain boundaries. However, the influence of grain boundary dopants on the mechanical behavior of stabilized NC materials is less clear. In this work, molecular dynamics (MD) simulations are used to study the impact of very low dopant concentrations (<1.0 at. pct Sb) on plastic deformation in single-crystal and NC Cu. A new interatomic potential for low Sb concentration Cu-Sb solid-solution alloys is used to model dopant/host and dopant/dopant interatomic interactions within the MD framework. In single-crystal models, the strained regions around the Sb atoms act as heterogeneous sources for partial dislocation nucleation; the stress associated with this process decreases with increasing Sb concentration. In NC models, MD simulations indicate that Sb dopants randomly dispersed at the grain boundaries cause an increase in the flow stress in NC Cu, implying that Sb atoms at the grain boundaries retard both grain boundary sliding and dislocation nucleation from grain boundary regions.     

Fast Sintering of Nanocrystalline Copper

The behavior of nanocrystalline (nc) copper specimens obtained by high energy ball milling (HEBM) and electromagnetic field-assisted sintering under stress and mechanical compression is explored. High yield stress values combined with plastic behavior are observed. The basic densification mechanisms involved in the production process and the peculiar action on the dislocation network are discussed.     

Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper

The influences of relatively high manganese (0.45 through 1.0 wt pct) and copper (0.56 through 1.13 wt pct) contents on microstructure development and phase transformation in three austempered ductile irons have been studied. The experimental ductile irons alloyed with copper and manganese are found to be practically free from intercellular manganese segregation. This suggests that the positive segregation of manganese is largely neutralized by the negative segregation of copper when these alloying elements are added in appropriate proportions. The drop in unreacted austenite volume (UAV) with increasing austempering temperature and time is quite significant in irons alloyed with copper and manganese. The ausferrite morphology also undergoes a transition from lenticular to feathery appearance of increasing coarseness with the increasing austempering temperature and time. SEM micrographs of the austempered samples from the base alloy containing manganese only, as well as copper plus manganese-alloyed irons, clearly reveal the presence of some martensite along with retained austenite and ferrite. X-ray diffraction analysis also confirms the presence of these phases. SEM examination further reveals the presence of twinned martensite in the copper plus manganese-alloyed samples. The possibility of strain-induced transformation of austenite to martensite during austempering heat treatment is suggested.     

离子交换树脂脱除铜电解液中的锑和铋

采用新型树脂SF-11脱除铜电解液中的锑和铋。结果表明,SF-11树脂可有效脱除电解液中的Sb、Bi、Fe3+,同时对Cu2+、Ni 2+等基本不吸附;当流速为4BV/h时,锑的脱除率≥95%,铋的脱除率≥75%。用EDTA作为脱附剂,树脂可再生使用。     

Mechanical Property Stability of Cu-Mo-Ni Alloyed Austempered Ductile Iron

The aim of present work is to investigate the influencing factors on mechanical property stability of Cu-Mo-Ni alloyed austempered ductile iron （ADI）. The results show that after austenitized at 900℃ for 2 h followed by austempered at 370℃for another 2 h, the mechanical property of the alloyed ADI can reach the Germanite GGG-100 standard, i.e. σb≮1000 MPa,δ≮5%, at 95% confidence level. And the satisfactory mechanical properties were obtained when the alloyed ADI was austenitized at 850℃ to 1 000 ℃ for 1-4 h, and austempered at 355℃ to 400℃ for another 1 h to 4 h. The microstructures, including nodule number, white bright zone content （martensite-containing interdendritic segregation zone） and retained austenite content, can significantly influence the mechanical properties of the ADI. In order to obtain the good combinations of strength and ductility, the volume fraction of white bright zone should he less than 5%, and the retained austenite contents maintain hetween 30 % and 40%. The application of inoculation techniques to increase graphite nodule number can effectively reduce the white bright zone content in the structure.     

Mechanical Properties and Friction／Wear Behavior of Copper Alloyed Powder Composites

Copper alloyed powder composites containing nanoparticles were developed by hot pressing. Effects of nanoscale activated sintering aid and fine ceramic particles Al2O3 on hardness, working quality, and behaviors of friction and wear of the composites have been studied, compared with the composites including mieroscale activated sintering aid and microscale ceramic particles. The microstructures of the samples were analyzed by SEM. The resuits show that the materials with nanoscale sintering aid and fine ceramic particles have better mechanical properties and abrasive resistance than the materials with microscale activated sintering aid and microceramic particles. Moreover, element mutual transfer occurs between samples (strip) and abrasive wheel (ring).     

原子吸收光谱法测定铜精矿中锑

铜精矿中锑作为杂质元素在铜精矿化验分析中是必检项目。微量锑的测定一般采用萃取富集后用分光光度法测定。但是该方法要使用苯或甲苯等有机试剂,这些有机试剂会对人员和环境造成伤害和污染。在国家标准铜精矿化学分析法中采用原子荧光光谱法测定微量锑。但许多中、小化验室因缺乏原子荧光光谱仪而无法开展。本方法充分利用铜精矿的铁,使其形成氢氧化铁与少量锑共沉淀而与铜、镍等元素分离,在稀盐酸介质中用原子吸收光谱法测定。方法简单快速,便于掌握。     

浅析砷锑在铜电解过程中的行为

通过对铜电解过程中阳极铜、阳极泥、砷锑渣、电解液悬浮物、电铜中杂质元素存在形态的分析 ,探讨砷锑在铜电解过程中的行为 ,以寻求稳定铜电解生产过程和提高电铜质量的方法     

高铜粗锑火法精炼除铜研究

采用熔析———加硫除铜两段工艺研究了综合回收得到的高铜粗锑火法精炼除铜的反应机理 ,并确定了除铜的最佳条件。在略高于锑熔点温度 (6 5 0℃ )下 ,熔析可以除去粗锑中 90 %以上的铜 ,铜与砷形成Cu3 As、Cu5As2 化合物进入渣相 ,粗锑含砷量越高 ,熔析效果越好。加硫除铜反应由生锑与锑液间的扩散过程控制 ,通过改进加硫方式 ,能除去熔析后残余铜的 75 %。通过两段除铜 ,锑中铜含量降至 0 0 4 %。     

从铜阳极泥分银渣中回收铋和锑

采用硫酸与氯化钠的混合溶液浸出铜阳极泥卡尔多炉分银渣。结果表明,铋、锑被浸出进入溶液,铅转化为硫酸铅留在浸出渣中,从而实现铅与锑、铋的分离。在硫酸浓度2.5mol/L、氯化钠浓度125g/L、液固比4∶1、温度95℃、浸出时间4h的条件下,铋、锑、铅、银的浸出率分别为98.67%、91.17%、0.56%和0.76%,金几乎不被浸出。     

萃取法回收铜电解液中锑铋研究与实践

以铜电解液为研究对象,采用有机相组成(N1923+磺化煤油+异辛醇)的萃取体系,物质A酸性络合反萃体系对铜电解液中锑铋回收工艺进行研究,确定工艺参数,并将研究成果应用于工业生产,结果表明,锑铋萃取率分别达84.1%和98.1%,锑铋反萃率分别达95.7%和90.6%,且不造成铜损失,对电解工艺无不良影响。     

高砷锑铜精矿水蒸气脱砷锑工艺试验

伴生有黝铜矿和砷黝铜矿的黄铜矿是一种比较典型的铜矿种。因其砷锑含量高,直接冶炼时会严重恶化冶炼环境,故在冶炼前必须进行脱砷脱锑预处理。文章研究采用水蒸气焙烧处理富含砷锑的黄铜精矿,考察了焙烧温度、焙烧时间、物料粒度、水蒸气流量和气氛对脱砷脱锑的影响。结果证明采用水蒸气焙烧的方法可以较为彻底地脱去砷和锑,达到冶炼的要求,并且和传统的预处理措施相比,成本低,污染程度轻。     

铜电解液中锑氧化还原规律及其价态转化途径

以含H2SO4、As、Sb、Bi的酸性溶液为研究体系,采用化学分析及电化学测试,研究了电解液中锑的氧化还原规律及价态转化途径。实验表明,在铜电解液中,溶解的氧气在一定温度下将Sb(III)氧化,其中砷可显著促进Sb(III)的氧化。通过向电解液中加入适量双氧水可实现电解液中锑的氧化,促进砷锑铋的共沉淀反应。电化学测试表明,加入Sb(III)后,阴极过程在-0.13 V出现还原峰,阳极过程在0.03 V出现氧化峰,随着三价锑浓度增加,阳极过程氧化峰电流先增大再减小。加入Sb(V)后,阴极过程在-0.1 V出现还原峰,阳极过程在0.05 V出现氧化峰,随着五价锑浓度的增加,阳极过程峰电流逐渐增大。采用H2O2氧化方法调节电解液中nSb(III)/nSb(V)至1∶4附近,Sb、Bi在一定条件下脱除率分别达到68.2%和83.7%。     

真空蒸发法从硫化锑渣中回收锑

针对锑工业生产过程中产生大量硫化锑渣的物料特性,通过理论分析研究,采用真空蒸发的方法处理硫化锑渣,并考察了物料粒径、体系压强、蒸发时间和蒸发温度对硫化锑渣蒸发率的影响。结果表明,在物料粒径0.106～0.075mm、体系压强50Pa、蒸发时间30min、蒸发温度923K的条件下,蒸余物中锑含量降至0.2%,硫化锑渣的蒸发率为27.9%,锑分离效率为98.6%。     

ICP-AES直接测定粗铅中锑、铜、铋

介绍了采用电感耦合等离子体原子发射光谱仪直接测定粗铅中的锑、铜、铋的方法,以硝酸-酒石酸消解试样,在10％硝酸介质中进行标准基体匹配,选择合适谱线进行测定,结果显示检出限低,回收率好,相对标准偏差较小,且测定范围广.     

合金化管铸铁冷却壁内冷却水管的变形研究

根据合金化管铸铁冷却壁热态试验数据确定了合金化管铸铁冷却壁温度场数值模拟的边界条件,利用ANSYS软件、采用热-结构耦合的方法计算了高温状态下合金化管铸铁冷却壁内钢质冷却水管的变形,分析了气隙层和水管热变形对合金化管铸铁冷却壁寿命的影响,得出保证合金化管铸铁冷却壁长寿的最佳气隙层厚度和相应的最佳使用热负荷.     

自旋阀结构多层膜的热稳定性

研究了Si/Ta/NiFe/Cu/NiFe/FeMn/Ta结构的自旋阀的热稳定性及层间扩散问题.高分辨电镜(HREM)观察表明,各层呈柱状晶生长.低于200℃退火能有效地提高钉扎场.高于200℃退火后,钉扎场下降,300℃时降为零.利用俄欧电子能谱仪(AES)研究了在相同的条件下制备的基片/Ta/NiFe/FeMn/Ta结构多层膜.结果表明,200℃以下时薄膜层之间主要发生沿晶界的扩散,300℃时体扩散的作用不能忽略.     

Producing Metallic Antimony with Low Arsenic Content from Antimony Concentrate

The basis of the concentrate is sodium hexahydroxoantimonate or mineral mopungite. Upon reduction of the concentrate with coke, ground antimony containing 0.34% arsenic was obtained. To reduce the arsenic content in the rough metal to 0.1% and exclude the stages of antimony refining from arsenic, reductive melting is proposed in the presence of lead compounds. Because of the smelting reduction of the antimonate concentrate in the presence of sodium plumbite or lead oxide, a rough antimony with an arsenic content of 0.07–0.1% was obtained. The process of reductive smelting of the antimonate concentrate on black antimony was carried out in an oven with silicate heaters in alundum crucibles with batches of charge of 100–150 grams. The content of impurities and the base metal in antimony was determined by chemical and atomic absorption methods. The form of arsenic in the concentrate was determined by X-ray phase analysis. The analysis was carried out on an automated diffractometer DRON-3 with CuK_α radiation, ß-filter. The concentration of arsenic in the slag phase in the form of lead diarsenate Pb₂As₂O₇ is shown. Thermal gravimetric analysis of the smelting reduction process of the antimonate concentrate was studied on the Q-1000/D derivatograph of the F. Paulik, J. Paulik and L. Erdey systems of the “MOM” company. Thermogravimetric researches of process of recovery melting of the furnace charge consisting of an antimony concentrate, lead oxide and coke as a result of which it is established that process of formation of metal antimony proceeds in the range of temperatures 445–950°C are conducted.     

薄型铜冷却壁的热性能

 为了降低高炉铜冷却壁的造价,开发了一种厚度为90 mm的薄型铜冷却壁。通过热态试验测量了高温下冷却壁的温度分布和冷面应变分布,通过数值模拟计算了冷却壁的温度场和应力应变场。热态试验和数值模拟结果符合较好。研究结果表明,薄型铜冷却壁能承受的最大热负荷为220 kW/m2,在高炉炉况下的基体温度以及由此产生的热应力都不足以使其破坏,满足长寿高炉的要求。