川北某黑色页岩型铼矿工艺矿物学研究

通过矿相显微镜、扫描电镜、电子探针、X射线能谱元素面分析等多种手段综合研究了川北某黑色页岩型铼矿中铼的赋存状态。样品为黑色页岩,有机碳含量较高。粘土矿物总量为14.6%,黄铁矿含量16.2%,石英含量37.7%。样品具典型的粘土结构,矿物粒度微细。铼有两种赋存状态,一种呈类质同象形式赋存于黄铁矿内,另一种则以分散形式存在。典型黄铁矿测点Re平均含量为0.024%。黄铁矿是Re的重要载体矿物。建议通过浮选分离黄铁矿,从而实现Re的富集。      

铬黑T-溴酸钠催化动力学分光光度法测定铼

基于在硫酸介质中,铼催化溴酸钠氧化铬黑T的褪色反应,建立了测定铼的光度分析新方法。确定了催化体系的动力学条件,计算得出催化反应的表观活化能Ea=39.12KJ/mol,反应速率常数为K=1.248×10-3/s。在选定的试验优条件下,铼的浓度在0~10.02mg/L范围内与相对吸光度呈良好的线性关系,检出限为2.7675mg/L。方法所用仪器简单,操作简便。     

The Effect of Sintering on the Properties of Ultrafine

研究了一种化学气相沉积(CVD)制备超细铼粉的新方法,即以NH4ReO7为原料,通过将其分解为Re2O7后气相输运至还原区,经氢气还原生成超细铼粉。对不同还原温度下制备的超细铼粉样品,采用XRD、SEM、激光粒度分析进行表征,实验揭示了烧结作用对晶粒尺寸、形貌、表面状态及粒度等粉末性能的影响规律。结果表明,随还原温度升高,烧结作用增强,制备的超细铼粉晶粒尺寸增大,具有更好的球形度,表面趋于光洁,平均粒径增大。     

加压浸出法从失效重整催化剂中分离铂铼

失效铂铼催化剂中铂铼性质相似,难以分离,采用碳酸钠加压浸出选择性分离铼,研究了浸出条件对铼浸出效率的影响。在反应温度为160℃,反应时间为150 min,浸出剂碳酸钠用量为物料量的8%,搅拌速率为500 r/min,液固比为4:1,反应压力为0.5 MPa的条件下,铼浸出率98.5%,铂基本不溶解而留在渣中,实现铂和铼的初步分离。     

Adsorption and separation of rhenium(VII) using N‐methylimidazolium functionalized strong basic anion exchange resin

BACKGROUND: Rhenium is a rare and valuable metal coexisting with molybdenum in molybdenite and sulfide copper ores and is hard to separate. Methods such as solvent extraction, ion exchange, adsorption, precipitation, etc. have been used to separate and purify Re(VII), and resin ion exchange has been widely investigated and used owing to its convenient operation and relatively low‐cost. The main challenge comes from the preparation of resins having high performance and stability. In an earlier study, an N‐methylimidazolium functionalized strong basic anion exchange resin was successfully synthesized and used for Cr(IV) extraction. This paper, reports on further synthesis and application of this resin for adsorption and separation of Re(VII) and Mo(VI), especially from copper arsenic filter cake. RESULTS: At pH 6.25, Re(VII) and Mo(VI) can be effectively separated with the N‐methylimidazolium functionalized strong basic anion exchange resin, giving a Re(VII) recovery of up to 93.3%, but only 5.1% for Mo(VI). When using the copper arsenic filter cake sample 89.1% Re(VII) recovery was achieved. CONCLUSION: The N‐methylimidazolium functionalized strong basic anion exchange resin exhibited high selectivity and recovery for Re(VII) in a mixed system. © 2012 Society of Chemical Industry     

Dehydrogenation of Light Alkanes Over Rhenium Catalysts on Conventional and Mesoporous MFI Supports

Recently, Re/HZSM-5 (Si/Al = 15) was shown to be an efficient catalyst for ethane dehydrogenation and aromatization at 823 K and atmospheric pressure. In this reaction, the major initial products were benzene, toluene and xylene (BTX), but increasing amounts of ethene were produced with time on stream due to deactivation of the catalyst. We show that by use of rhenium impregnated MFI supports with very few or no acidic sites (Si/Al > 500), highly selective ethane dehydrogenation catalysts are obtained with ethene selectivities of 98%. By use of mesoporous MFI supports (Si/Al >500) the lifetime of the catalyst appears to be slightly improved compared to conventional MFI crystals. The beneficial effect of a mesoporous MFI support is convincingly demonstrated in propane dehydrogenation, where both conversion and selectivities on the mesoporous MFI (Si/Al > 500) impregnated with Re are significantly higher than on Re supported on a comparable conventional MFI support.     

The Effect of Water on the Activity and Selectivity for γ-Alumina Supported Cobalt Fischer–Tropsch Catalysts with Different Pore Sizes

The effect of water on the activity and selectivity for a series of γ-Al₂O₃ supported cobalt Fischer–Tropsch catalysts has been studied in an isothermal fixed-bed reactor at T = 483 K, P = 20 bar, and H₂/CO = 2.1. The catalysts were produced applying incipient wetness impregnation and consisted of 20 wt.% cobalt and 0.5 wt.% rhenium deposited on γ-Al₂O₃ supports with different pore characteristics. For the narrow-pore catalysts, addition of water corresponding to an inlet partial pressure ratio of P_H2O/P_H2 = 0.4 reduced the reaction rates. In contrast, for a catalyst with larger pores the same water pressure increased the reaction rates. For all catalysts, water amounts equal to P_H2O/P_H2 = 0.7 at the reactor inlet suppressed the reaction rates and led to permanent deactivation. The addition of water increased the C₅₊ selectivity and decreased the CH₄ selectivity for all catalysts. The pore characteristics seem to determine the effect of water on the rates.     

CVD法制备的Ir/Re涂层复合材料界面扩散研究

采用化学气相沉积(CVD)技术制备了Ir/Re 涂层复合材料,并在高温高真空条件下对复合材料样品进行扩散热处理。应用电子扫描波谱法探针研究了Ir/Re复合材料界面Re元素在Ir涂层中的扩散规律。应用半无限大扩散模型进行处理,得到了1400-2000℃温度范围的实验扩散系数,扩散系数与温度之间符合Arrhenius方程。根据实验结果推算,Ir/Re复合材料在2200℃时的工作寿命为47.6小时。     

铼的回收技术研究进展

综述了从矿石、冶炼废液、废催化剂、废旧合金物料中回收铼的主要工艺技术,并对其关键技术进行了分析。结果表明,从矿石及冶炼废液中回收铼的技术相对较为成熟;高效、清洁的离子交换树脂、萃取剂的开发将会是铼冶金领域的重大革新。从废催化剂、废旧合金等铼的二次资源中回收铼的研究较少,尚需开发适合于规模化、工业化应用的回收技术,这是今后铼回收方面的重要研究课题。