(NH_4)_2HPO_4-NH_3·H_2O-H_2O系APT溶解度研究

采用溶解平衡法研究了(NH_4)_2HPO_4-NH_3·H_2O-H_2O系APT的溶解性能。随着氨水浓度增大,APT溶解度由略微下降转为较快上升,溶液中磷钨杂多酸浓度大幅降低,而同多钨酸根和正钨酸根浓度大幅升高。相同磷酸氢二铵浓度下(NH_4)_2HPO_4-NH_3·H_2O-H_2O系APT溶解度远大于(NH_4)_2HPO_4-H_2O系。     

(NH_4)_2〔Ce(NO_3)_6〕的制备及其水溶性研究

着重讨论水溶性较大的(NH_4)_2 〔Ce(NO_3)_6〕络合物制备过程中酸度、硝酸铵量、温度等对其合成的影响,并用(NH_4)_2 〔Ce(NO_3)_6〕-NH_6NO_3-H_2O的罗什布相图说明硝酸高铈铵在硝酸铵的水溶液中的溶解度变化。     

用NH3-(NH4)2CO3-H2O体系从高炉瓦斯灰中浸出锌试验研究

研究了以NH_3-(NH_4)_2CO_3-H_2O体系从高炉瓦斯灰中浸出锌,考察了温度、总氨浓度、液固体积质量比、[NH_3]/[NH~+_4]、搅拌速度和浸出时间对锌浸出率的影响。结果表明:在25℃、总氨浓度5 mol/L、液固体积质量比4 mL/g、[NH_3]/[NH~+_4]=1/1、搅拌速度300 r/min、浸出时间30 min条件下,锌浸出率达76.71%,浸出效果较好。     

（NH4）3PO4-NH3·H2O-H2O体系中磷酸铵溶解度

采用等温溶解度法测定了10～70℃时（NH4）3PO4-NH3·H2O-H2O三元系中磷酸铵的溶解度,并绘制成相应的相图。结果表明：磷酸铵的溶解度随温度降低和氨浓度升高而下降。当溶液中氨浓度相同时,温度越低,则磷酸铵的溶解度越小。采用氨溶析结晶法从磷酸铵溶液中除去钾、钠杂质时,可通过提高溶液中氨浓度以及降低温度的方式,使得磷酸铵结晶析出,钾和钠留在结晶母液中,除去钾、钠,以达到净化提纯磷酸铵的目的。     

(NH_4)_2HPO_4-H_2O系仲钨酸铵溶解性能及磷钨杂多酸形成的影响

采用溶解平衡法研究了(NH_4)_2HPO_4-H_2O系仲钨酸铵(APT)的溶解性能。结果表明:当温度低于70℃时,仲钨酸铵的溶解度随磷酸氢二铵浓度的升高而减小;当温度达到70℃以上时,仲钨酸铵的溶解度随磷酸氢二铵浓度的升高而增大。在高温下磷钨杂多酸的形成是仲钨酸铵溶解性能和溶解速率大幅提高的主要原因。     

铁粉-H_2O_2对PdCl_3SC(NH_2)_2~-的还原

以含PdCl_3SC(NH_2)_2~-溶液为原料,采用Fe-H_2O_2还原法回收溶液中的钯,研究了还原过程的机理,考察了pH、还原时间、H_2O_2用量和铁粉用量对还原率的影响。结果表明,铁粉被氧化后的Fe~(2+)可催化H_2O_2而产生氧化能力极强的·OH自由基,该自由基对复杂的PdCl_3SC(NH_2)_2~-结构具有很强的破坏力,使稳定的PdCl_3SC(NH_2)_2~-以PdCl _4~(2-)形态分离出来,提高了铁对钯的还原性能。在溶液体积20mL,25℃,pH=2,H_2O_2用量0.10mL/mL,反应时间60min和铁粉用量0.50mg/mL的条件下,钯的平均还原率可达99.25%。     

空气对Mg(NH_2)_2-2LiH材料放氢性能的影响

采用Sievert's体积法、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)和差示扫描量热仪(DSC)等分析手段研究暴露空气前后Mg(NH_2)_2-2Li H-0.07KOH储氢材料的放氢性能及其影响机制。研究表明,粉末状样品经空气暴露后,其中的Mg(NH_2)_2和LiH与空气中的O_2和H_2O发生剧烈反应,生成MgO,LiNH_2,Li_2O和Li2Mg(NH)_2,各产物之间不能够发生放氢反应,样品放氢容量几乎为零。而压实体样品经空气暴露后,仅样品表面的Mg(NH_2)_2和LiH可与空气中的O_2和H_2O反应生成Mg O,LiNH_2和Li_2O。样品的放氢容量由暴露空气前的4.68%降至3.32%(质量分数),放氢反应动力学也相应减慢,这是由于新生成的Mg O,Li NH_2和Li2O能够减慢Mg(NH_2)_2和LiH之间界面反应的传质过程,阻碍放氢过程中氢气的扩散,样品放氢反应激活能提高,放氢反应速率减慢。压制成型使Mg(NH_2)_2-2Li H-0.07KOH材料的应用安全性能显著提高。     

Na2WO4的溶剂萃取转化

本文研究了用 N235-TBP-煤油体系将较高浓度 Na_2WO_4溶液转化成高浓度(NH_4)_2WO_4溶液的萃取工艺。年产100tWO_3的半工业实验表明,强化反萃取过程的传质和降低酸浓度是克服反萃取过程中形成 APT 的有效方法。     

Mg(Ⅱ)-NH_3-NH_4Cl-H_2O体系中Mg(Ⅱ)配合平衡热力学

用双平衡法研究了Mg(Ⅱ)-NH_3-NH_4Cl-H_2O体系中Mg(Ⅱ)配合平衡热力学,得出氨水浓度和氯化铵浓度在0～5 mol/L范围内变化时体系中各物种的平衡浓度,绘制了热力学平衡图,揭示了镁在该体系中的溶解规律。该体系存在着镁的高溶解度区域,镁的溶解度随着氯化铵浓度增加而增加,最高可达1.07mol/L;而在纯氨水中,镁离子浓度不随氨水浓度变化,始终接近0;向体系中添加氯化铵并保持其浓度不变,镁离子浓度随着氨水浓度的升高先略有降低而后逐渐升高,呈现一个浅碟型,在氨水浓度为2.5mol/L附近出现最低点。     

稀土脯氨酸高氯酸盐配合物[RE_2(Pro)_6(H_2O)_4](ClO_4)_6(RE=Pr,Er)的低温热容及热力学性质

合成了两种纯度分别是 99.2 4%和 98.2 0 %的单晶稀土脯氨酸高氯酸盐配合物 [Pr2 (Pro) 6 (H2 O) 4](Cl O4) 6 和 [Er2 (Pro) 6 (H2 O) 4](Cl O4) 6 ,对该配合物进行了热容、热重、差热和标准燃烧热等测定。在 78～ 370 K温度区 ,用高精密全自动绝热量热仪测定了热容值 ,计算机拟合得其热容对温度的多项式方程分别为 :Cp=140 7.0 8 75 1.6 7X 170 .17X2 89.5 9X3- 76 .11X4和 Cp=1317.99 6 33.0 5 X 16 3.82 X2 15 0 .2 3X3- 86 .2 1X4,[Er2(Pro) 6 (H2 O) 4](Cl O4) 6 的 Cp- T曲线有一熔化峰 ,计算熔点为 35 5 .5 5 K,熔化熵为 6 9.5 42 J/(K m ol) ,熔化焓为2 472 5 .81J/m ol。 TG、DTA技术研究了其热分解过程 ,初步分析了配合物的分解机理。燃烧热实验给出了它们的标准燃烧热分别为 1772 0 .41k J/mol和 1810 1.6 5 k J/m ol     

用乳状液膜从硫酸铵型浸出液中浓缩稀土

在作者所做的＂用乳状液膜从氯化钠型浸出液中浓缩稀土＂的工作基础上，利用所获得的液膜体系和较佳工艺条件，继续进行了料液类型［即ＮａＣｌ型和（ＮＨ４）２ＳＯ４型浸出液的比较实验］、ＮａＡｃ用量、膜相中有无石蜡、膜回用等条件实验，获得了从（ＮＨ４）２ＳＯ４型浸出液中浓缩稀土的适用液膜体系Ｎ２０５－Ｐ５０７－煤油－ＨＣｌ乳状液膜浓缩稀土的浓度达１０２ｇ／Ｌ，稀土提取率达９３％。     

吐温80——硫酸铵——水固——液萃取分离金的研究

报道了吐温８０－（ＮＨ４）２ＳＯ４－水的固液萃取体系中Ａｕ（Ⅲ）溴络阴离子ＡｕＢｒ４－的萃取行为,Ｈ２ＳＯ４－ＮＨ４Ｂｒ介质中,该体系可定量萃取Ａｕ（Ⅲ）,而常见贱金属不被萃取,可用于从贱金属基体中分离金,对合成样及实际样品进行了萃取分离,并对机理进行了初步探讨。     

Polymerization of N-Phenylmaleimide Catalyzed by (ArO)_2Sm(THF)_4

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NIR emitting terephthalates(Sm_xDy_yGd_(1-x-y))_2(tph)_3(H_2O)_4 for luminescence thermometry in the physiological range

The first luminescence thermometer based on coordination compound of samarium and dysprosium is repo rted.High luminescence intensity and high signal resolution are reached thanks to the concentration quenching reduction due to the use of the trimetallic complexes of Sm-Dy-Gd.The best thermometric properties in a wide temperature range among the studied systems are demonstrated by(Sm_(0.2)Dy_(0.15)Gd_(0.65))_2(tph)3(H_2 O)_4.The sensitivity reaches 0.5%/K in visible range and 1.2%/K in NIR range at low temperatures and 0.5%/K and 0.8%/K in physiological range.     

Electronic Structure and Chemical Bonding of a Tetranuclear Neodymium Complex Nd_4O(OR)_4(NR''''_2)_6

The nonrelativistic DV-X_α-SCC method was used to study the electronic structure and chemi-cal bonding of tetranuclear neodymium complex Nd_4O(OR)_4(NR′_2)_6,with emphasis on the bonding charac-ter of the central μ_4-O atom and the four Nd atoms.The results of calculation show that the μ_4-O atom usesits sp~3 valence orbitals to contribute four O-Nd bonding MOs with character of multicenter bond apparent-ly.The Mulliken population analysis shows that the overlap population between Nd atoms is almost equal tozero,therefore there is no direct metal-metal bond between Nd atoms.The coordination number of Nd in thecomplex is discussed briefly.     

Spectroscopic properties of ytterbium doped KLu（WO_4）_2

Monoclinic Yb3+-doped KLu(WO4)2 (Yb:KLuW) crystal with large sizes was grown by top-seeded solution growth (TSSG) method. Room-temperature absorption and fluorescence spectra were measured. The ground-state energy-level splitting was 562 cm-1. The absorption cross section, peak emission cross section as well as the minimum inversion fraction ?min and the minimum absorbed pump intensity Imin were calculated. The measured emission lifetime was 0.676 ms and the emission spectral bandwidth (FWHM) was up to 55 nm. In comparison with established laser crystals the results suggested that this crystal has potential application in efficient tunable and femtosecond laser operation.     

Structure and Luminescent Enhancement Effect of Na_5Eu(MoO_4)_4 by Doping(WO_4)~(2-)

The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)~(2-) has been studied.When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0相似文献   

固溶体Er_(2-x)Ho_x(WO_4)_3的热膨胀性能研究

用固相化学反应法制取了Er2-xHox(WO4)3(x=0.0～0.4,1.2～2.0)系列固溶体,利用XRD实验及Rietveld结构精修分析研究了Er2-xHox(WO4)3系列固溶体的晶体结构和热膨胀性能,结果表明Er2-xHox(WO4)3(x=0.0～0.4,1.2～2.0)系列化合物沿着三个晶向是呈异性负热膨胀性能。     

Emission Spectra and Crystallographic Sites of Eu~(2+) in Ca_8Zn(SiO_4)_4Cl_2

The fluorescent characteristic and emission spectra of Eu~(2+) in the cubic structureCa_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu~(2+) concentra-tion and excitation conditions on fluorescent properties of Eu~(2+) are studied at 77 and 298 K.Thecoordination number of Eu~(2+) at different sites is obtained.The green and red emission bands arise fromEu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.