新技术与新成果

2011022独居石稀土精矿、独居石与氟碳铈混合型稀土精矿的焙烧分解方法一种独居石稀土精矿、独居石与氟碳铈混合型稀土精矿的焙烧分解方法,属于冶金技术领域,针对现有技术中高温硫酸焙烧分解稀土精矿过程中环境污染的问题,本发明采用氧化钙加氯化钠助溶剂,焙烧分解独居石稀土精矿、独居石与氟碳铈混合型稀土精矿,焙烧过程在空气下进行,助剂加入量为5%～30%,焙烧温度为600～950℃,焙烧时间为10～90     

氯化铵焙烧法从中品位氟碳铈矿精矿提取稀土的研究

采用氯化铵焙烧法分解中品位氟碳铈矿精矿(REO～30%),热水浸取焙砂后,浸取液采用环烷酸全捞制备氯化稀土产品。研究了氯化反应温度、氯化剂用量及氯化时间等因素对稀土氯化率的影响。将中品位氟碳铈矿精矿与2倍氯化铵混合并加入少量添加剂,在480℃焙烧1.5h,焙砂用90℃热水浸取得氯化稀土浸出液,稀土收率为82.8%,浸出液进一步用环烷酸全捞,浓缩结晶得相对纯度为99.2%的氯化稀土产品。     

采用固氟氯化法从氟碳铈矿中提取稀土氯化动力学的研究进展

针对我国主要的稀土矿物氟碳铈稀土矿目前在分解回收中主要采用浓硫酸焙烧法产生氟化氢污染环境的问题,清华大学核能与新能源研究院从1998年以来开展了氧化镁固氟、氯化铵选择性氯化提取氟碳铈中稀土及其动力学的研究。选择我国典型的稀土矿物包头混合型稀土矿及山东氟碳铈稀土矿展开研究,确定了适宜的工艺条件、氯化选择性和氟的转化形态。稀土以氯化稀土形式被浸取,对于两种稀土矿物稀土浸出回收率均在85%以上。氯化铵氯化稀土的氯化动力学符合Bagdasarym提出的多相区域反应动力学模型,氯化反应的速率αRE遵从Erofeev方程。氯化铵氯化不同形态氧化稀土氯化反应表观活化能的大小顺序为:EaLa2O3+CeO2相似文献   

选择性氯化法提取白云鄂博中品位混合精矿中稀土

白云鄂博中品位混合稀土精矿经脱氟处理 ,采用氯化铵法回收稀土。考察了反应温度、时间及固氟剂用量对稀土氯化的影响。在最佳条件下稀土浸出回收率达到 85 %。而浸出液中非稀土杂质的含量低 ,特别是钍的含量仅为 0 .0 0 0 1g/ L (WRE/Th=8.0 5× 10 4) ,从而实现了稀土与钍等非稀土的预分离。达到了选择性氯化混合稀土矿中稀土的目的     

氟碳铈精矿空气中焙烧的热分解研究

利用ＤＴＡ、ＴＧ、ＸＲＤ及化学分析等方法对山东微山的氟碳铈精矿在空气中焙烧的反应过程进行了研究。指出氟碳铈精矿的分解过程可分为两步，首先较低温度下，（Ｃｅ，Ｌａ）ＣＯ＿３Ｆ氧化分解为（Ｃｅ，Ｌａ）Ｏ＿（１＋ｘ），Ｆ＿（１－ｘ）；随着焙烧温度的提高，（Ｃｅ，Ｌａ）Ｏ＿（１＋ｘ）Ｆ＿（１－ｘ）继续氧化分解，得到Ｃｅ＿（０．７５）Ｎｄ＿（０．２５）Ｏ＿（１．８７５）和Ｌａ＿２Ｏ＿３等，焙烧过程中部分脱氟，样品总失重率达１９．５４％。     

冕宁氟碳铈矿除氟萃取铈(Ⅳ)工艺研究

本文研究了冕宁氟碳铈精矿加分解助剂进行焙烧时的温度、时间及分解助剂用量对稀土提取率的影响。研究了对焙烧矿进行水洗除氟过程中水温、洗涤次数、ＡｌＣｌ３加入对除氟效果的影响以及硫酸浸取除氟矿时硫酸浓度、酸浸时间对稀土提取率的影响。讨论了Ｐ２０４皂化度、浓度、料液中Ｃｅ（Ⅳ）的浓度、酸度对Ｃｅ（Ⅳ）萃取分配比的影响以及萃取络合物形式、萃取平衡时间等。     

氟碳铈稀土精矿压团工艺研究

本文研究了氟碳铈稀土精矿造块时精矿粒度、粘结剂用量、团块烘干温度及烘干时间对团块抗压强度的影响。     

AlCl3脱氟-碳热氯化法提取包钢选矿厂尾矿中稀土

研究了包钢选矿厂尾矿经AlCl3脱氟后加碳氯化焙烧提取氯化稀土的新工艺.系统考察了反应时间、温度和脱氟剂对稀土提取率的影响.结果表明在脱氟剂AlCl3存在下,800℃时氯化反应2h,稀土提取率高达88.6%.采用XRD法分析了不同温度下尾矿碳热氯化2h酸不溶物的物相组成,探讨了AlCl3脱氟-碳热氯化法从尾矿中除氟并提取氯化稀土可能发生的反应.     

硼酸焙烧氟碳铈精矿的物相变化及铈与非铈稀土的酸浸分离

物相组成为混合稀土氧化物和氟化物的氟碳铈精矿加硼酸焙烧后,发生了稀土物相的变化,铈成为难溶于酸的二氧化铈晶格,非铈稀土生成易溶于酸的硼酸镧晶格,扩大了欲分离的铈与非铈稀土之间的的性质差别。因而,从精矿分离铈与非铈稀土获得成功。借助于 x—衍射物相分析研究确定了精矿的稀土晶格结构,探讨了焙烧反应过程。其氟碳铈精矿与硼酸焙烧的主要反应为:〈1〉RxOy H_3BO_3CeO_2 LaBO_3 H_2O↑〈2〉RF_3 H_3BO_3 H_2OCeO_2 LaBO_3 HF↑     

碳酸钠焙烧盐酸浸出分解氟碳铈矿精矿工艺的研究

系统地研究了焙烧温度、焙烧时间和碳酸钠的加入量对氟碳铈矿精矿焙烧分解的影响及浸出时间、浸出温度、盐酸浓度和盐酸用量对三价稀土和铈的浸出率的影响。针对氟碳铈矿精矿的分解,提出了碳酸钠焙烧、水洗除杂、稀盐酸浸出处理氟碳铈矿精矿的简单工艺。在实验室内扩大实验的条件下,首次由焙烧、浸出两步制得了高质量的高铈抛光粉,同时也得到了制取少铈富镧氯化稀土的原料。     

Effects of Ce3＋ , Nd3＋ , Gd3＋, Tb3＋ and Lu3＋ ions on Formation of CaCO3

The effects of lanthanides at various concentrations on CaCO3 crystal growth were studied by X-ray diffraction (XRD), infrared spectra (IR), X-ray photoelectric energy spectra (XPS) and inductively coupled plasma mtms spectrometry (ICP-MS). It was found that the calcite, a stable form of CaCO3 in thermodynamics, is the predominant species. The research indicates that lanthanide ions (Ln3 ) can partly substitute the Ca2 in the lattice of CaCO3 crystals, and change the crystal characterization and direct the ordinal growth of CaCO3 crystals.     

Photoluminescence of Dy~(3 ) Ions in Ba_3La(BO_3)_3

Dy3 isanimportantactivator .Ithasbeenexten sivelyappliedinmanyluminescentmaterials .Inre centyears ,someresearchershavestudiedthespec trumcharacteristicsofluminescentmaterialsdopedDy3 [1～ 6 ] andhaveobtainedsomemeaningfulre sults .InordertodevelopnewfluorescentmaterialsanddiscussthephotoluminescentruleofDy3 inthecomplexborate ,thispaperstudiesthephotolumines centcharacteristicsofDy3 inBa3La(BO3) 3host ,anddiscussestheinfluenceofthecharge to radiusratio(z/r)ofrareearthionRE3 andthecon…     

3-Hydroxy-3-methylglutaric aciduria: deficiency of 3-hydroxy-3-methylglutaryl coenzyme A lyase

Basic principles are offered to support the suggestion that use of special care space must be made with a mind toward prevention of obsolescence. Certain conventional design features should be examined critically and decisions made as to their applicability to the needs of a particular program.     

Dy^3＋在（LaO）3BO3和（GdO）3BO3中的光致发光

研究了Ｄｙ＾３＋在（ＬａＯ）３ＢＯ３和（ＧｄＯ）３ＢＯ３中的光致发光;探讨了基质晶体结构、稀土离子ＲＥ＾３＋的电荷半径比（Ｚ／ｒ）和Ｄｙ＾３＋含量对（Ｄｙ＾３＋）发光强度及发光颜色的影响;分析了（ＧｄＯ）３ＢＯ３中Ｂｉ＾３＋对Ｄｙ＾３＋发光的敏化作用及Ｄｙ＾３＋４Ｆ９／２→＾６Ｈ１３／２超灵敏跃迁发射的自身浓度猝灭机理。     

Ca3La(BO3)3中Dy3+的光致发光

研究了Ca3La(BO3)3基质中Dy^3 的发射光谱和激发光谱。结果表明，强的激发峰值为351nm、367nm和386nm；Dy^3 的488nm和578nm发射的最佳浓度均为xDy=0．03；Dy^3 发射的黄光和蓝光强度比(用Y／B表示)随Dy^3 浓度的增加而逐渐增大；Dy^3 的^4F9/2→^6H15/2、^6H13/2跃迁发射的浓度猝灭机理均为电偶极-电偶极相互作用；同时还探讨了Ce^3 对Dy^3 发光的敏化作用。     

Optical Spectroscopy of Er^3＋ and Er^3＋/Yb^3＋ Co-doped Bi2O3-GeO2-B2O3-ZnO Glasses

The （60 - x）Bi2O3 - xGeO2-30B2O3-10ZnO （x = 5, 10, 20, 30 molar percent） glasses doped with Er^3＋ and Er^3＋/Yb^3＋ were fabricated using the melting method. The thermal stability of the glasses was studied with their DTA curves. The results show that the difference between the glass transition temperature and the crystallization onset temperature increases with the increase of GeO2 content, indicating that the thermal stability of the glass has become better. The absorption spectra were recorded and the stimulated emission cross sections were calculated using the McCumber theory. The Ω2, O4, and Ω6 parameters,the transition probability, the radiative lifetime, and the fluorescence branch ratio of Er^3＋ for optical transition were calculated from their absorption spectra in terms of reduced matrix U^（t）（λ = 2, 4, 6） character for optical transitions. The infrared emission of Er^3＋ was measured upon excitation with 970 nm light and the full width at half-maximum （FWHM） was estimated from the emission spectra. The pumping efficiency and the intensity of the emission at the 1.54 μm band of Er^3＋ were enhanced considerably by co-doping Yb^3＋ .     

K3AlF6-Na3AlF6-AlF3铝电解体系密度的研究

采用流体静力称重法研究了K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>铝电解质体系的密度.探讨了K<,3>AlF<,6>,AlF<,3>含量和温度与K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>体系密度的关系.实验结果表明:K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>体系密度与温度成较好的线性关系,温度升高,密度降低;随着AlF<,3>含量的降低,体系的密度对温度的变化更加敏感.相同过热度下,固定KR(钾冰晶石含量),随着AlF3含量的增加,体系的密度呈现出不同的变化规律,相同过热度条件下,对于较低的KR=0.1值,随着AlF<,3>含量的增加,体系的密度逐渐下降,对于较高的KR=0.5值,随着AlF<,3>含量的增加,体系密度先降低后增加,存在最低点.相同过热度下,固定AlF<,3>含量,随着KR增加,体系密度也呈现出不同的变化规律,当AlF<,3>为22%,随着KR增大,体系密度变化不大;当AlF<,3>为26%,30%,随着KR增大,体系密度先降低后增加.     

Enhanced ultraviolet upconversion in YF3：Yb^3＋/Tm^3＋ nanocrystals

Unusual intense infrared-to-ultraviolet upconversion luminescence was observed in YF3:Yb3+(20%)/Tm3+(1%) nanocrystals under 980 nm excitation. The intense ultraviolet emissions (1I6→3H6, 1I6→3F4, and 1D2→3H6) were affirmed arising from the excitation processes of five-photon and four-photon. In comparison with the bulk sample with the same chemical compositions, ultraviolet upconversion lumi-nescence of the nanocrystals was markedly enhanced. Spectral analysis indicated that the enhancement was attributed to the decrease of Judd-Ofelt parameter Ω2, which precluded the transition rate from 3F2 to 3F4, enhanced the energy transfer process and populated the 1D2 level: 3F2→3H6 (Tm3+): 3H4→1D2 (Tm3+).