白云鄂博中贫氧化矿弱磁-强磁-浮选联合流程综合回收稀土研究

本文洋细分析讨论了采用弱磁—强磁—浮选工艺流程,稀土矿物的分选行为和规律,认为强磁选作业能有效地将磁性很弱的稀土矿物预先富集在强磁中矿。强磁中矿与其它流程浮选稀土的原料相比,具有矿物组成简单,未受药剂污染、且基本无细泥的优点,通过浮选易于获得高品位的稀土精矿,并使稀土回收率有较大幅度的提高。该工艺流程选别稀土具有技术先进,经济合理的特点。     

磁浮新工艺选别白云鄂博中贫氧化矿铁、稀土、铌第二阶段工业分流试验

本文简述了采用弱磁—强磁—浮选工艺流程选别(?)云鄂博主东矿(?)贫氧化矿综合回收铁、稀土、铌的第二阶段工业分流试验结果,分析讨论了主要怍业的选别效果,认为该工艺流程能较好地全面地回收铁、稀土、铌等有价成分,并为萤石等非金属资源的综合利用创造了较好的条件。     

Polymorphism in Gd2Ge2O7 ceramics: Structural,vibrational, and optical features

In this work, Gd₂Ge₂O₇ polymorphs were obtained by solid-state reactions at 1100–1300 °C. Structural and vibrational features were investigated by X-ray diffraction and Raman spectroscopy. For the triclinic (space group P1) polymorph, all the predicted phonons were discerned in perfect agreement with the group theory calculations, while for the tetragonal polymorph (space group P4₁2₁2), 53 bands of the 81 predicted modes could be identified and characterized. The Gd³⁺ 4f-4f electronic transitions were investigated by diffuse reflectance spectroscopy in the range 200–340 nm. By applying the Kubelka-Munk function, it was possible to determine the bandgap values for all ceramics studied. The tetragonal polymorph exhibited higher bandgap values (5.88 eV) than the triclinic one (5.59 eV), which are both more energetic than other pyrochlore polymorphs reported in the literature. The results indicate that the presence of polymorphism in Gd₂Ge₂O₇ ceramics can be used to produce tailor-made materials since their crystal structures have a strong influence on their optical properties. Consequently, these properties could be used to tuning the optical properties of Gd-containing materials to sensitize and transfer energy to other luminescent lanthanide ions, aiming for innovative applications.     

从包钢选矿厂尾矿中回收稀土的工艺研究

研究了包钢选矿厂尾矿经AlCl3或MgO脱氟后加碳氯化提取稀土的反应原理和工艺,考察了碳热氯化反应时间和脱氟剂对稀土提取率的影响。结果表明:700℃碳热氯化2h,在脱氟剂AlCl3存在下,稀土提取率可达77%;在脱氟剂MgO存在下,稀土提取率可达84%。     

LPE InP layers grown in the presence of rare-earth elements

Preparation and characterisation of InP layers grown by Liquid Phase Epitaxy with the addition of several rare-earth (RE) elements into the growth melt is reported and the influence of Ho, Er, Nd Pr, and Yb is compared. Low-temperature photoluminescence (PL) spectra have been measured for various levels of excitation power and temperature. The major manifestation of the RE admixture is the pronounced narrowing of PL curves and the corresponding appearence of fine spectral features. Particularly in the case of Nd and Pr admixtures the acceptor related PL band exhibits a structure that permits an individual determination of acceptor and donor binding energies. Temperature dependent Hall effect and capacitance–voltage curves also show quite dramatic impact of Pr and Nd on shallow impurity and free-carrier concentrations: they were reduced by as much as three orders of magnitude.     

磁浮联合流程全面回收白云鄂博铁、稀土、铌及钪合理性的探讨

依据白云鄂博矿中贫氧化矿主要矿物的选矿特性,在磨矿细度-74μm占90%,铁、稀土、铌单体解离度不太高的情况下,采用弱磁—强磁—浮选联合流程,首先将矿物进行合理分组,简化铁、稀土(铌)粗精矿中的矿物组成,提高铁,稀土、铌的单体解离度,并使恶化浮选作业的矿泥基本得到脱除,然后通过浮选,较经济地得到优质铁精矿、稀土精矿、稀土次精矿、富铌铁精矿等4种产品。另外,富铌铁精矿、浮铌尾矿、铁正浮尾矿中,钪有很大程度的富集,是良好的选冶提钪原料。磁浮联合流程大大提高了白云鄂博中贫氧化矿综合利用程度。     

白云鄂博大型多金属共生矿选矿研究的回顾与展望

白云鄂博矿床是世界特有的铁、稀土、铌、钪等多金属共生矿床,以矿物的贫、细、杂、难选而闻名于世。该矿的选矿研究,经过了30多年漫长而坎坷的道路,取得了巨大的成绩。本文系统地介绍了各个时期的主要研究工作,重点论述了近年来选矿研究取得的成就,并对今后的选矿研究工作提出了建议。     

贵金属与稀土金属的相互作用:(V)Rh-RE和Ir-RE系

根据现有的相图和中间相的资料,绘制了Rh-RE和Ir-RE系相图的简并示意图,讨论了Rh、Ir与RE间相互固溶度、包括共晶与包晶反应在内的各类反应,评述了主要中间相的结构特征及其分布,预测了某些中间相的存在和结构。     

Comparative study of Er3+ and Tm3+ co-doped YOF and Y2O3 powders as red spectrally pure upconverters

We prepared Er³⁺ and Tm³⁺ co-doped yttrium oxyfluoride (YOF) powder by combustion synthesis and we observed that under near-infrared (λ = 980 nm) laser excitation the characteristic green (²H_11/2, ⁴S_3/2 → ⁴I_15/2) emission of Er³⁺ was suppressed by energy transfer (ET) mechanisms between Tm³⁺ and Er³⁺. The ET process observed in YOF was much more efficient than that observed in standard Y₂O₃ powder prepared under similar conditions. YOF combines the superior mechanical and thermal properties of oxides with low phonon energy of fluorides. Our results show that this material is a serious candidate for use as a red upconversion phosphor.     

Luminescent layers for enhanced silicon solar cell performance: Down-conversion

A down-converting (DC) layer placed on the front side of a silicon solar cell has the potential to generate more than one low-energy photon for every incident high-energy photon. Recent theory has predicted that DC in conjunction with a silicon solar cell can achieve a conversion efficiency of up to 38.6%. This paper examines the application of rare-earth-doped inorganic materials for achieving external quantum efficiencies greater than unity and enhancing the conversion efficiency of silicon solar cells. Such DC mechanisms have been applied in similar phosphor materials used by the lighting and display industries. The opportunities for the DC of high-energy solar photons to multiple photons with energy greater than the silicon bandgap are discussed.