Thermochemical Properties of Ternary Complex Yb[（C5H8NS2）3（C12H8N2）]

Thermochemical Properties of Ternary Complex Yb[(C_5H_8NS_2)_3(C_(12)H_8N_2)]     

Precipitation-dissolution behaviors of rare earth ions in H_3PO_4-Ca(H_2PO_4)_2 solutions

In order to achieve deeper understanding of rare earth elements(REEs) behaviors during phosphate rock processing with H_3PO_4. The solubility of REEs in Ca(H_2PO_4)_2-H_3PO_4 solutions with various concentrations of Ca(H_2PO_4)_2 at different temperatures were tested. The results demonstrate that REEs solubility decreases sharply with the increasing concentration of Ca(H_2PO_4)_2. Equations between [REE~(3+)] and [H~+],[H~+] and [Ca~(2+)] in Ca(H_2PO_4)_2-H_3PO_4 solutions were built based on the precipitation-dissolution equilibrium of rare earth phosphates and the ionization equilibrium of H_3PO_4. According to the equations, the decreasing mechanism of REEs solubility caused by elevated concentration of Ca(H_2PO_4)_2 was determined. The mechanism can be illustrated as that the elevated concentration of [H_2 PO_4~-] decreases the concentration of hydrogen ion by retarding the ionization process of H_3PO_4 and directly promotes the precipitation of rare earth phosphates. Furthermore, it can be easy deduced that similar effect would be caused by the other cation impurities(Fe~(3+), Al~(3+), etc.) on REEs solubility based on the mechanism. In addition, superimposed reduction effect on REEs solubility caused by the elevated concentration of Ca(H_2PO_4)_2 and the elevated temperature is found. This superimposed effect leads to a super low solubility of REEs in Ca(H_2PO_4)_2-H_3PO_4 solution. On the basis of the experimental study, outlooks and suggestions for further development of REEs recovery method are given.     

Hp303捕收剂浮选萤石的研究

以多种石油化工和有机化工副产物为原料，辅之以一定的泡沫调整剂，合成了新型捕收剂Ｈ＿（ｐ３０３）．Ｈ＿（Ｐ３０３）浮选萤石具有良好的捕收性和选择性，工业生产试验表明：ＨＰ＿（Ｐ３０３）优于油酸．     

Ni（OH）2氢还原法制备超细镍粉过程的反应动力学研究

本文采用ＴＧ、ＤＴＧ方法研究了Ｎｉ（ＯＨ）２在Ｈ２中还原制备超细镍粉过程的反应机理。并用Ｄｏｙｌｅ－Ｏｚａｗａ法和Ｋｉｓｓｉｎｇｅｒ法测定了还原反应的动力学参数，反应的活化能力１００．２５ｋＪ／ｍｏｌ，反应级数为１．０８。还原反应为一步完成的。     

Magnetocaloric effect and magnetic properties of La_（0.9）Ce_（0.1）（Fe_（0.99）Mn_（0.01））_（11.6）Si_（1.4）H_（1.6） compound

Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.     

硅钨酸/TiO_2复合光催化材料光解水催化性能研究

采用浸渍法制备了复合杂多酸H4SiW12O40/TiO2光催化材料,并用XRD、FT-IR和UV-Vis-DRS研究了其结构形态,同时考察了H4SiW12O40/TiO2光催化剂对光解水制氧的应用研究。结果表明,H4SiW12O40/TiO2仍然保留Keggin结构,TiO2均匀固载在H4SiW12O40中,H4SiW12O40与TiO2之间仅仅是简单的物理吸附。在紫外光辐射下光催化分解水制氧的实验中,H4SiW12O40/TiO2的光催化析氧速率高达231.37μmol/(L.h),为纯H4SiW12O40的1.37倍。     

Corrosion mechanism of H_2O on Sm_2Fe_(17) and nitrogenation process of corroded Sm_2Fe_(17)

Sm_2 Fe_(17) prepared by reduction-diffusion method needs to be washed with water to remove calcium oxide. Electrochemical corrosion occurs when Sm_2 Fe_(17) powder is in contact with liquid water. Corrosion mechanism of H_2 O on Sm_2 Fe_(17) powder and nitrogenation process of corroded Sm_2 Fe_(17) were studied by analyzing the structure and morphology. It is indicated that the metallic hydroxide forms and deposits on the Sm_2 Fe_(17) powder surfaces during water corrosion. At the same time, oxygen and hydrogen enter the unit cell of Sm2 Fe_(17), causing a slight increase in Curie temperature. In the subsequent nitriding process,the hydroxide is dehydrated and hydrogen is desorbed. The resulting oxide reacts with Sm_2 Fe_(17)N_x to form a-Fe and Sm_2 O_3. Thermodynamic calculations using the HSC Chemistry 6.0 software indicate that the reaction can occur spontaneously. The effect of water corrosion on the magnetic properties of the nitride can be eliminated by hydrogen reduction prior to nitriding.     

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.     

Copolymerization of Butadiene and Isoprene by NdC_6H_6(AlCl_4)_3-AlR_3 System

This paper reported the copolymerization results of butadiene and isoprene catalyzed byNdC_6H_6(AlCl_4)_3-AlR_3 system.The results show that the catalytic activity is dependent on the weight ratioof butadiene and isoprene,the concentration of comonomers,the nature of alkylaluminium and thepolymerization temperature as well.High contents of 1,4 microstructure of copolymer are obtained by thenovel catalyst system.     

Hydrothermal synthesis and crystal structure study of two novel 3-D mellitates {Nd_2[C_6(COO)_6](H_2O)_6} and {Ho_2[C_6(COO)_6](H_2O)_6}

Two novel 3-D coordination compounds, Nd2[C6(COO)6](H2O)6 (1) and Ho2[C6(COO)6](H2O)6 (2), were hydrothermally synthe-sized from mellitic acid and neodymium perchlorate (or holmium perchlorate) in the alkaline aqueous solution and characterized with ele-mental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the ortho-rhombic system, space group Pnnm, with a=1.3531 (4) nm, b=0.6687 (2) nm, c=1.0224(3) nm, V=0.92523(5) nm3, Z=4, D=2.630 g/cm3, F(000)=696.0, Goof=1.052. Final R indices [I >2Σ(I)]: R1=0.0195, wR2=0.0382 for 1; a=1.3411(2) nm, b=0.6586(1) nm, c=1.0116(2) nm, V=0.8935(3) nm3, Z=4, D=2.877 g/cm3, F(000)=724.0, Goof=1.061. Final R indices [I >2Σ(I)]: R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.     

H_1Cr_(21)Ni_(10)Mn_6焊丝在冷拉过程中断裂原因分析及补救方法

H_1Cr_(21)Ni_(10)Mn_6不锈焊丝在冷拉过程中会出现断裂现象。其主要原因是H_1Cr_(21)Ni_(10)Mn_6钢中α相含量过高所致。为防止断裂的发生应适当增加退火道次,减少单道次变形量及控制总变形量,改善润滑条件。     

Synthesis Crystal Structureof Quaternary Mixed AnionComplex of Lanthanides[Ln(CCl_3COO)_2 (CH_3COO)(phen) (H_2O)]_2

Synthesis Crystal Structureof Quaternary Mixed AnionComplex of Lanthanides[Ln(CCl_3COO)_2 (CH_3COO)(phen) (H_2O)]_2     

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     

[Y(dbm)_3(H_2O)]:Synthesis,thermal behavior and spin-coating precursor for Y_2O_3 layer formation

The synthesis,structure and thermal behavior of [Y(dbm)_3(H_2 O)](3)(dbm = 1,3-diphenyl-1,3-propandionate) and its use as a spin-coating precursor for Y_2 O_3 deposition is reported. Complex 3 was prepared by the reaction of [Y(NO_3)_3·6 H_2 O](1) with 3 equiv of Hdbm(2) in presence of NaOH. The molecular structure of 3 in the solid-state was determined by single X-ray crystal diffraction. Both C_1 symmetric crystallographically independent species of 3 possess a YO7 coordination setup with minor deviation from an ideal capped octahedron coordination geometry(∧ enantiomer). Complex 3 forms a1 D chain, due to intermolecular hydrogen bonds between the coordinated H_2 O molecule and the 0 atom of the dbm ligand, respectively. The thermal decomposition behavior of 3 was investigated by thermogravimetric studies in the temperature range of 40-800 ℃ and 40-1300 ℃ under an oxygen and argon atmosphere, respectively. Powder X-ray diffraction(PXRD) measurements of the residues confirmed the formation of Y_2 O_3. Complex 3 was applied as a spin-coating precursor for yttrium oxide film formation on either Si wafers with a continuous 100 nm thick SiO_2 film, or with a native oxide layer.The as-deposited Y_2 O_3 layers are smooth, conformal, dense and transparent and are of a thickness of 27 and 30 nm, respectively.     

Low-temperature heat capacities of crystalline Ho(Gly)_3Cl_3·3H_2O from 78 to 348 K

Heat capacities of the rare-earth complex with glycine [Ho(Gly)3Cl3·3H2O] were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 348 K.In the experimental temperature range,the heat capacities increased in a smooth and continuous manner and no phase transition or thermal anomaly occurred.Therefore,the sample was stable in the above temperature range.The values of experimental heat capacities were fitted to a polynomial equation with least square method and ...     

Low-temperature heat capacities of crystalline Ho(Gly)_3Cl_3·3H_2O from 78 to 348 K

Heat capacities of the rare-earth complex with glycine [Ho(Gly)3Cl3·3H2O] were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 348 K.In the experimental temperature range,the heat capacities increased in a smooth and continuous manner and no phase transition or thermal anomaly occurred.Therefore,the sample was stable in the above temperature range.The values of experimental heat capacities were fitted to a polynomial equation with least square method and ...     

Effect of Cl~- on electrochemical corrosion behavior of H_2S

In the process of natural gas transportation in high-sulfur oil and gas fields,the inner wall of the pipeline absorbs large quantities of condensate water due to the different temperatures inside and outside the pipeline. This condensate water dissolves a number of other ions. On one hand,these ions lead to the dissolution of H_2S and reduce the concentration of the acid corrosion reduction due to the ions having the same effect as salt. On the other hand,the ions in the electrochemical corrosion process can promote charge transfer and accelerate electrochemical reactions. Polarization curves and AC impedance measurements were used to investigate the effects of different Cland S~(2-) concentrations on the electrochemical behavior of H_2S.     

氢气还原1～3mm铁矿粉的动力学研究

在自制的kg级高温流化床中研究了氢气还原1～3 mm矿粉的动力学试验。随着时间的增加,气体利用率下降,表明还原前期反应速度快,后期反应慢;温度越高,气体利用率越高,但随着还原时间的增加,差距在逐步缩小;对于750℃,前20 min的气体利用率为9%,金属化率达到84%,说明氢气还原矿粉反应是非常迅速的。随着气速的增加,金属化率在增加,并且几乎成线性关系,因此使用氢气作为还原剂,可以允许更高的气速,从而提高设备的生产效率。随着料高的增加,金属化率不断下降,然而气体利用率却在不断升高。使用氢气作为还原剂,可以将还原温度降低到700～750℃,避免流化床过程中的粘结难题;试验中氢气还原1～3 mm铁矿粉时的表观活化能为58.4kJ/mol。     

氢气还原氧化铁动力学的非等温热重方法研究

 用非等温热重分析法对氢气还原不同粒度细微氧化铁的动力学进行了研究。研究表明：铁矿粉粒度越小,起始反应温度越低,反应速度越快,反应达到平台期时所对应的还原率越高;平均粒度为3.5 mm的铁矿粉在400 ℃还原反应开始,700 ℃左右开始反应加快,达到平台期时的还原率为77%,而平均粒度为2 μm的铁矿粉在100 ℃已经开始反应,350 ℃反应加快,达到平台期时的还原率为98%,而且在600 ℃时还原率就达到了100%;铁矿粉粒度从3.5 mm降到2 μm后,还原反应的表观活化能从73.3 kJ/mol降低到30.46 kJ/mol;同时通过分析氢气还原氧化铁的反应机理得出,内扩散和界面化学反应均对整个反应过程起限制作用。     

蓝钨氢还原制取钨粉

探讨了蓝钨氢还原过程中影响钨粉粒度的主要因素，提出了制取细钨粉应采取的工艺措施。