钢中稀土对化学热处理的影响与作用机理

介绍了钢中稀土对离子氮化、离子硫氮碳共渗及气体渗碳的影响，提出了钢中稀土促渗的“气团－通道”模型。指出稀土是通过直接和间接作用来加速氮、碳的扩散与氮、碳化物的形成。因此，钢中稀土具有显著的促渗作用，并提高渗层硬度。     

On the Mechanism of Sodic Removal from Bauxite Residue and Bauxite Desilication Products (BDP) Using Acetic Acid

JOM - Bauxite desilication products (BDPs) are fundamental causes of persistent alkalinity and salinity in bauxite residue. Previous studies have shown that significant amounts of acetic acid and...     

从锌浸出渣中回收银的方法

一般湿法炼锌厂所产出的锌浸出渣含有相当数量的银、锌及稀散金属。近２０年来，人们从这类残渣中回收银及人价金属的研究和生产方法归纳起来可分为３类；浮选富集，火法富集和直接浸出银。讨论了各种方法的基本原理，优点和缺点，以及研究方向。     

Micro-alloying of Rare Earths in Heavy Rail Steel

In the present study, heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects of Rare earths (RE) on microstructure and mechanical properties of heavy rail steel were systematically investigated by metallographic microscope, SEM, integrated mechanical testing machine, impact tester and so on. Metallographic analysis shows that, a few of RE can evidently delay the growth of austenite grain and fine pearlite. When the RE content is 0.016%, both anneal...     

稀土在电工用铝母线中的应用实践

介绍了生产电工用稀土铝母线的主要工艺技术，分析了稀土在电工用铝母线生产中的作用。生产实践表明：稀土具有良好的净化铝熔体、细化晶粒和对杂质相的变质作用，当Ce加入量为0.066％时，铝母线成品的平均抗拉强度、伸长率及导电率分别比国家标准值提高29.7％、50.0％和4.4％，可满足大多数场合的使用要求。     

氮甲醇渗碳气氛中稀土的催渗作用

研究了在氮甲醇渗碳气氛中加入稀土元素,在860℃渗碳温度下,稀土元素对渗碳过程的影响。发现在该温度及不同渗碳时间（从0.5h到4h0下,对不同钢（15CrNi3Mo,20CrNiMo和20钢渗碳,稀土均有明显的催渗效果。     

中国灯用稀土荧光粉行业的发展现状

介绍了我国灯用稀土荧光粉行业的现状及存在的主要问题，阐述了提高灯用荧光粉质量的途径，并对稀土荧光粉的发展趋势提出了建议。     

稀土在高温超导材料中的应用

简要介绍了迄今后发现的各类含稀土超导材料;论述了稀土钡铜氧高温超导体在工艺上和技术应用上的进展;指出轻稀土钡铜氧特别是钕钡铜氧块材适于批量生产,具有经济。潜力。     

Refining and Mutual Separation of Rare Earths Using Biomass Wastes

Two different types of adsorption gels were prepared from biomass wastes. The first gel was produced from astringent persimmon peel rich in persimmon tannin, a polyphenol compound, which was prepared by means of simple dehydration condensation reaction using concentrated sulfuric acid for crosslinking. This adsorption gel was intended to be employed for the removal of radioactive elements, uranium (U(VI)) and thorium (Th(IV)), from rare earths. The second gel was prepared from chitosan, a basic polysaccharide, produced from shells of crustaceans such as crabs, shrimps, prawns, and other biomass wastes generated in marine product industry, by immobilizing functional groups of complexanes such as ethylendiaminetetraacetic acid and diethylentriaminepentaacetic acid (DTPA). This gel was developed for the mutual separation of rare earths. Of the two adsorption gels evaluated, the DTPA immobilized chitosan exhibited the most effective mutual separation among light rare earths.     

矿用纳米稀土硬质合金的磨损性能研究

以石英砂为磨料,研究了YG12硬质合金的冲击磨料磨损性能与其纳米稀土添加量、硬度及断裂韧度之间的关系。结果表明,随着纳米稀土含量的增加,该硬质合金的磨损体积先减小再增大,加入1wt%纳米稀土时,其磨损量最小;随着硬度、断裂韧度的增加,合金的抗磨损性能提高。岩石颗粒的混合、粘结相的脆变和WC晶粒的破碎是矿用纳米稀土硬质合金的主要磨损机制。     

稀土对6063铝合金阳极氧化膜厚度的影响

在硫酸、硫酸亚锡溶液中对添加稀土的６０６３铝合金进行阳极氧化和电解着色,系统地研究了氧化电解液浓度、温度、时间、电流密度对膜层厚度的影响．结果表明：稀土可以明显地提高６０６３铝合金氧化膜厚度,稀土含量以０．２０％为好．     

等离子质谱法测定铝土矿中的稀土元素

称0．2000g试样于根坩埚中，经KOH和Na2O2熔融分解，热水浸取、HClO4沉淀钾离子，和蒸发脱水除SiO2后，用Rh和Re作内标ICP-MS法测定稀土元素。方法的测定限小于0.93ng/g，经标准样品分析验证，其结果与标准值基本吻合，3次平行测定的RSD在0.044%-3.88%之间。     

Dealkalization of Bauxite Residue Through Acid Neutralization and Its Revegetation Potential

Bauxite residue is a highly alkaline industrial solid waste generated through the alumina production process. Its high alkalinity causes serious environmental pollution. In this article, a fast, high-efficiency, low-cost dealkalization process was developed. Bauxite residue was dealkalized by sulfuric acid and CAM, a calcium-containing compound. The revegetation potential of dealkali bauxite residue was also studied. The dealkalization rate reached up to 94.31% when 18.4% sulfuric acid was added, and 2% CAM leaching occurred at room temperature for 10–30 min. The filtration speed increased by about 70 times with the addition of CAM up to 4.5%. The subsequent pot experiment showed that the dealkali bauxite residue met the growth requirements of plants. Scanning electron microscopy analysis showed that the particle size of neutralized bauxite residue was enlarged, thereby accelerating the soil formation process of the bauxite residue. This work provides technical support for ecologic restoration of a bauxite residue disposal area.

     

从含铂碘化银渣中回收银铂的新工艺

提出了一种从碘化银渣中回收银铂的新方法。经过水合肼还原、熔炼铸锭、浓硫酸分银三步分离银铂。用传统的方法精炼铂,海绵铂的纯度为99.95%,铂回收率为99.5%。得到的银粉制硝酸银,银的回收率为99%。     

氰渣综合利用提取金银的试验研究

通过正交试验详细考察了矿浆浓度、硫酸过剩系数、反应温度和反应时间等因素对氰渣浸铁率的影响.结果表明矿浆浓度为35%、硫酸过剩系数为1.3、反应温度为100℃、反应时间为2.5 h的试验条件下,铁的浸出率最高,可达97.80%.对比氰渣和浸铁渣金、银的氰化浸出效果发现氰渣再氰化金、银的浸出率分别为5%和10%,而浸铁渣再氰化金、银的浸出率则分别高达87%和80%,因此氰渣浸铁再氰化是提高金、银回收率的有效途径之一.     

含铑树脂中铑的回收工艺研究

采用水溶液氯化法、王水溶解法和水溶液氯酸钠氧化法等3种湿法工艺从含铑树脂中回收铑,重点研究了溶解体系、反应温度、反应时间和液固比等对铑溶解率的影响。结果表明,在液固比12:1 mL/g、反应温度90℃、反应时间20 h的条件下,采用水溶液氯化法铑溶解率达到95%,经精炼后得到合格铑粉,铑的回收率达到92%。     

稀土含量对38CrMoAl钢渗氮层性能的影响

为了克服38CrMoAl钢渗氮速度慢,渗层脆性大,稀土添加到渗氮气氛中只能作用于工件表面等缺点,研究了38CrMoAl钢中不同稀土添加量对渗氮层性能的影响,并初步分析了其影响机制。研究结果表明：稀土对38CrMoAl钢渗氮具有明显的催渗作用,且能提高渗层性能。原因是稀土加入钢中后,引起周围铁原子的点阵畸变,有利于氮原子的吸附和扩散,且稀土易与渗氮气氛中的氧结合,削弱了氧对渗氮的阻碍作用;同时稀土的晶粒细化、固溶体强化、微合金化也是其改善渗层性能的重要原因。     

镧铈混合稀土变质Al-28%Si活塞合金

采用镧铈型混合稀土对过共晶Al-28%Si活塞合金进行了变质处理,对其显微组织和力学性能进行了研究。结果表明:与单一稀土铈变质相比较,镧铈型混合稀土对该合金具有较好的变质效果,初晶硅的尺寸基本保持在20μm左右,且尖角大多钝化呈团球化状,共晶硅呈短杆状均匀分布;合金经过混合稀土变质后,晶界处产生复杂化合物组织起到了弥散强化作用,使其综合力学性能明显提高,尤其是高温强度的显著提高,已完全满足活塞合金在使用性能上对高温强度的要求。