查看更多>>摘要：In this paper,we analyzed the physical characteristics of the ternary alloys RE2Rh3Ge(RE=Pr and Sm)using the first principles calculation based on functional density theory integrated in the Wien2k code.The calculated formation energies of Pr2Rh3Ge and Sm2Rh3Ge are-5.3827 and-5.2782 eV/atom,respectively,showing that these alloys may exist stably.The results of the band structure and density of states indicate that all of the compounds tested are magnetic metals,and their magnetism is mostly related to the contribution of Pr and Sm atoms.The total magnetic moments of Pr2Rh3Ge and Sm2Rh3Ge are 4.07245 and 11.16161 μB/f.u,respectively.Thermodynamic parameters such as heat capacity at constant pressure,entropy,Debye temperature,lattice volume,compressibility coefficients,and Grü-neisen parameter alloys were calculated using the Gibbs algorithm and studied in depth over a large temperature range of 0-900 K.The Debye temperature increases with increasing pressure and decreases with decreasing temperature.Moreover,the Debye temperatures calculated at p=0 GPa and T=300 K are equal to be 342 and 322 K for Pr2Rh3Ge and Sm2Rh3Ge,respectively.The optical characteristics such as the real and imaginary portions of the dielectric function,the absorption coefficient,the energy-loss function,and the refractive index were investigated and discussed in more depth.
查看更多>>摘要：Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most common mining method.The high contents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A comprehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ leaching.This paper improves a five-step sequential extraction method to analyze the occurrence and vertical distri-bution of rare earths and aluminum in vertical profiles from Chongzuo and Longyan.Experimental re-sults demonstrate that soil solution pH is the main factor affecting the vertical distribution of ion-exchangeable rare earths.Both samples have distinct areas of enrichment for ion-exchangeable rare earths or aluminum.Ion-exchangeable rare earths are primary concentrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay minerals.The inorganic hydroxy aluminum concentration in Chongzuo samples decreases continuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the concentration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling depth.These results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the consumption of leaching agent.
NETL
NSTL
万方数据