通过对拉拉矿床矿物共生组合、矿物生成顺序、矿石特征的研究,发现其矿石矿物以磁铁矿为主,铁和铜的硫化物次之,并含有大量稀土矿物和自然金。拉拉矿床至少经历了两期成矿作用:早期为区域变质成矿作用,晚期为热液成矿作用。早期形成Fe R...通过对拉拉矿床矿物共生组合、矿物生成顺序、矿石特征的研究,发现其矿石矿物以磁铁矿为主,铁和铜的硫化物次之,并含有大量稀土矿物和自然金。拉拉矿床至少经历了两期成矿作用:早期为区域变质成矿作用,晚期为热液成矿作用。早期形成Fe REE P矿化,晚期为Cu Mo Au Co (U)矿化。根据这些特征,首次指出该矿床属于铁氧化物 铜 金 铀 稀土型矿床,而不是以往所称的块状硫化物型铜矿。展开更多
Hydriding-dehydriding process has been widely employed to comminute uranium alloys. Developments have been made to improve this process because it is a cheaper way to obtain powder of uranium alloys compared to the ot...Hydriding-dehydriding process has been widely employed to comminute uranium alloys. Developments have been made to improve this process because it is a cheaper way to obtain powder of uranium alloys compared to the other methods, such as atomization. This work presented an innovative comminution process of U-10Mo alloy in laboratory scale where a Sievert type equipment was utilized and only hydriding cycles were employed without repetition of the dehydriding procedure. Experiments of comminution of the U-10Mo alloy were carried out by employing alloy samples which were submitted to different heat treatment conditions and, subsequently, to different hydriding cycles. The heat treatments considered were hot rolled at 800 ℃, homogenization at 900 ℃ or 1,000 ℃ and aging at 520℃. It was observed that the number of hydriding cycles and heat treatment conditions have influenced the particle size distributions. Samples that were hot-rolled, homogenized at 1,000 ℃ and aged, and comminuted with five cycles of hydriding have produced powders with particle size distribution more uniform with the major quantity of particles in the range from 50μm to 200 μm while the other conditions have obtained a great quantity above 200 μm.展开更多
ABSTRACT Urania-paUadium-graphene nanohybrids were synthesized via a solvothermal process in ethylene glycol. With the solvothermal treatment, the Pd nanocrystals sur- rounded by well-crystallized urania supported on ...ABSTRACT Urania-paUadium-graphene nanohybrids were synthesized via a solvothermal process in ethylene glycol. With the solvothermal treatment, the Pd nanocrystals sur- rounded by well-crystallized urania supported on graphene oxide was obtained. This ternary hybrid showed consid- erably higher catalytic activity than palladium-graphene hybrids toward the reduction of 4-nitrophenol by NaBH4. Besides the smaller sizes of palladium nanoparticles in the ternary hybrids, in which the aggregation of Pd nanoparticles was prevented by urania, the charge transfer between the nano-structured Pd and urania may also contribute to the enhancement of catalytic activity by offering more active sites for adsorption and reaction.展开更多
文摘通过对拉拉矿床矿物共生组合、矿物生成顺序、矿石特征的研究,发现其矿石矿物以磁铁矿为主,铁和铜的硫化物次之,并含有大量稀土矿物和自然金。拉拉矿床至少经历了两期成矿作用:早期为区域变质成矿作用,晚期为热液成矿作用。早期形成Fe REE P矿化,晚期为Cu Mo Au Co (U)矿化。根据这些特征,首次指出该矿床属于铁氧化物 铜 金 铀 稀土型矿床,而不是以往所称的块状硫化物型铜矿。
文摘Hydriding-dehydriding process has been widely employed to comminute uranium alloys. Developments have been made to improve this process because it is a cheaper way to obtain powder of uranium alloys compared to the other methods, such as atomization. This work presented an innovative comminution process of U-10Mo alloy in laboratory scale where a Sievert type equipment was utilized and only hydriding cycles were employed without repetition of the dehydriding procedure. Experiments of comminution of the U-10Mo alloy were carried out by employing alloy samples which were submitted to different heat treatment conditions and, subsequently, to different hydriding cycles. The heat treatments considered were hot rolled at 800 ℃, homogenization at 900 ℃ or 1,000 ℃ and aging at 520℃. It was observed that the number of hydriding cycles and heat treatment conditions have influenced the particle size distributions. Samples that were hot-rolled, homogenized at 1,000 ℃ and aged, and comminuted with five cycles of hydriding have produced powders with particle size distribution more uniform with the major quantity of particles in the range from 50μm to 200 μm while the other conditions have obtained a great quantity above 200 μm.
基金supported by the Ministry of Science and Technology of China (2016YFA0201904)National Natural Science Foundation of China (21631002 and U1632119)
文摘ABSTRACT Urania-paUadium-graphene nanohybrids were synthesized via a solvothermal process in ethylene glycol. With the solvothermal treatment, the Pd nanocrystals sur- rounded by well-crystallized urania supported on graphene oxide was obtained. This ternary hybrid showed consid- erably higher catalytic activity than palladium-graphene hybrids toward the reduction of 4-nitrophenol by NaBH4. Besides the smaller sizes of palladium nanoparticles in the ternary hybrids, in which the aggregation of Pd nanoparticles was prevented by urania, the charge transfer between the nano-structured Pd and urania may also contribute to the enhancement of catalytic activity by offering more active sites for adsorption and reaction.
