Thermal and radiative characteristics of oxyfluoride glass singly doped with lanthanide ions

Rare earths-doped oxyfluoride glasses based on germanium oxide and lead fluoride were prepared from commercial raw materials. The glasses with general composition of 50GeO2-(50-x-y)PbO-yPbF2-xLnF3 (Ln=Pr3+-Yb3+), contained different concentrations of optically active dopants (x=0.2 mol.% and 2 mol.%) and PbF2 (y≤15 mol.%). The differential thermal analysis (DTA) was used to determine both thermal characteristic and thermal stability properties of the glasses in the function of the kind of dopant, its concentration, and a glass composition. Characteristic glass temperatures such as glass transition temperature (Tg), glass crystallization temperature (Tc) and temperature corresponding to the maximum of the crystallization rate (Tpc) were evaluated. On the basis of obtained results, the thermal stabilities of glasses under study were evaluated using various thermal stability criteria (Dietzel factor ?T, Saad-Poulain factors H' and S). It was found that the increase in rare earth fluoride contents influenced thermal characteristics when the characteristic temperatures of the individual glass was shifted towards higher values. The effect of the PbF2 content and the kind of rare earth impurity on the glass stability was observed. Absorption spectra of lanthanide-doped glasses were measured at room temperature and used to determine the phenomenological intensity parameters Ωt and next, to estimate radiative properties of lanthanide ions in this matrix. Radiative transition probabilities of luminescent states of Ln3+, branching ratios and radiative lifetimes were determined. The variation of the Ωt along the lanthanide series was presented and discussed.     

Process optimization of electroless copper plating and its influence on electrochemical properties of AB5-type hydrogen storage alloy

The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature,pH value and Ni2+concentration,and the relevant regression equation was expressed as y=2.1609+0.5295×10-3T2-0.0342P2-0.0265N2+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N.The results showed that the deposition rate augmented with the increasing in temperature,pH value and Ni2+concentration.The experimental parameters of the optimal coating were temperature 75 ℃,pH value 8.5 and Ni2+concentration 1.2 g/L.The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%,indicating that the treated alloy exhibited better corrosion resistance.     

Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

天铁热力风机升级改造方案设计

通过对天铁集团高炉现状、风机现状的分析,提出了对热力厂风机升级改造的规划,确定了实施方案.该方案实施后将彻底改变风机渐进式改造的现象,使新高炉的备用机组发挥更大的作用,可增加现有高炉的风压、风量,使现有高炉的产量、冶炼强度进一步提高.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

Recent progress report on DNA B-Z transition modulated by rare earth-amino acid complex and Alzheimer's disease amyloid beta

Rare earth dements have unique physical, magnetic, luminescent and catalytic properties. They have been successfully used as medicine and probes in luminescent resonance energy transfer (LRET) for bioassays, as well as reagents for diagnosis in magnetic resonance imaging (MRI). In this progress report, we will focus on recent progress on how rare earth amino complexes bind to DNA and change DNA structure, especially on DNA B-Z transition induced by rare earth amino acid complex and its potential impact on Alzheimer's disease (AD).     

Numerical Simulation on Inclusion and Bubble Entrapment in Solidified Shell in Model Experiment and in Mold of Continuous Caster With DC Magnetic Field

A model experiment investigating entrapment of inclusions and bubbles on the solidified shell was performed using molten steel,and the conditions for inclusion and bubble entrapment and mechanism of entrapment were studied.The results were applied to the flow behavior in the casting mold of a continuous caster.At the solid-liquid interface,entrapment of inclusions is greatly reduced by the existence of a low velocity flow,e.g.,0.05m/s.The above-mentioned interfacial flow velocity dependency of inclusion entrapment is considered to be largely influenced by changes in the thickness of the concentration boundary layer,which depend on the interfacial flow velocity.Specifically,bubbles and inclusions which enter the concentration boundary layer are drawn to the solid-liquid interface by a suction force which is several orders larger than the Saffman’s force.In addition to the above-mentioned suction force,the so-called cleaning effect is determined by fluid-dynamic forces such as drag force,etc.which act on particles,and furthermore,by resident time of particles at the solid-liquid interface,which depends on the solidification rate.In a FC mold with a 2-stage electromagnetic brake,flotation of bubbles entrained in the jet flow from the nozzle is accelerated with the large DC magnetic field.This is attributed to the braking effect of the DC field on the nozzle jet and the upward flow by the buoyancy of the bubbles.As a result,the interfacial flow velocity can be normalized by increasing the strength of the magnetic field,and entrapment of large bubbles and inclusions can be reduced.     

湿法炼锌浸出渣减量化浸出工艺研究

以常规湿法炼锌工艺锌浸渣为研究对象,对比研究常压酸浸和加压酸浸条件下锌浸渣的酸性浸出减量化效果,以及渣中锌、铜和铟等有价金属的浸出率。结果表明,在常压酸浸条件下,渣量可减少65%以上,渣中锌含量可降至3%左右,锌、铜和铟的浸出率均在91%以上;在加压酸浸条件下,渣量可减少40%以上,渣中锌含量可将至2%以下,锌和铜的浸出率达到95%左右,但铟浸出率仅为70%左右,相对较低。常压酸浸过程锌浸渣中的铁绝大部分浸出,有利于铟的浸出;加压酸浸过程锌浸渣中的铁大量以铅铁矾的形式留在渣中,阻碍了铟的浸出。常压浸出液中铁含量较高,达到25 g/L以上;加压浸出液中铁含量较低,小于2 g/L,有利于后续浸出液中铜、铟的回收。常压浸出渣量少,有利于渣中铅、银的富集,可单独销售;加压浸出由于铁沉淀入渣,致使渣中铅、银富集比低,适合于铅锌联合企业返回铅熔炼炉。     

中浸渣的机械活化浸出工艺研究

硫化锌精矿焙烧矿的中性浸出渣常含有锗等有价元素，常规低酸高酸两段浸出流程锗的直收率低。试验探寻了机械活化浸出工高锗浸出率的可能性，表明在试验确定的机械活化浸出条件下，两段浸出过程锗和锌的浸出率可分别提高19．98％和32．765，机械活化浸出是一有良好应用前景的工艺技术方向。     

硫化锌精矿焙烧浸出与直接浸出结合提锌同时除铁的方法

介绍了一种硫化锌精矿焙烧浸出与直接浸出结合提锌同时除铁的方法,利用硫化锌精矿氧压浸出除铁原理,浸锌同时除铁,取消了热酸浸出的除铁过程,简化了设备及工艺流程,提高了锌回收率,可以达到节能、环保、高效。     

氰化浸金过程中过氧化物的助浸作用

介绍了过氧化物在氰化浸金工艺中的应用、作用机理及主要影响因素。过氧化物在适宜条件下可以提高氰化浸金的速率，降低氰化物的耗量。     

氧压酸浸法从铌钛铀矿中选择性提取铀

采用氧压酸浸工艺选择性提取铌钛铀复杂多金属矿石中的铀,并对浸出过程铀、铌、钛、铁等元素的溶出行为进行了研究。结果表明,在硫酸用量240g/kg、矿浆液固体积质量比1.5mL/g、浸出反应温度180℃、氧气分压0.5MPa、反应时间6h条件下,铀浸出率可达到97.2%,而铌、钛、铁等则留于浸出残渣中。实现了从复杂难破解多金属矿石中高效选择性提铀的目的。     

两种加压浸出工艺处理锌浸出渣试验

开展了两种加压浸出工艺处理锌浸出渣的试验研究。“加压还原浸出+氧压浸出”取代原针铁矿工艺的“三段逆流热酸浸出+还原”,锌焙烧矿到铅渣的渣率为15.74%,锌、铁、铜、铟、镁的浸出率分别为99.32%、93.50%、95.02%、91.03%、99.97%,各项指标均优于原工艺,锌、铟的浸出率分别提高了1.82、11.03个百分点,反应时间由14 h缩短为4 h,液固分离次数由4次减少为2次。“两段逆流加压浸出”取代原黄钾铁矾工艺的“硅浸+预中和+黄钾铁矾沉铁”,锌焙烧矿到二段渣的渣率为35.88%,锌、铁、铜、铟、镁的浸出率分别为98.50%、4.94%、90.48%、2.69%、93.77%,各项指标均优于原工艺,浸出后液（相当于水解除铁后液）可以直接返回中性浸出工序,反应时间由16 h缩短为4 h,液固分离次数由3次减少为2次。加压浸出采用密闭的加压釜,更容易实现整个炼锌系统蒸汽平衡,无需额外增加蒸汽锅炉。     

不同浸出条件下硫化钴镍渣的浸出及动力学

研究了不同反应温度、固液比、氧分压、搅拌转速、浸出液浓度和反应时间对硫化镍钴渣中钴和镍的浸出规律及动力学的影响。结果表明：钴和镍浸出的较优条件为：反应温度120 ℃、固液比1︰30 g/mL、氧气分压0.7 MPa、搅拌转速230 r/min、硫酸浓度1 mol/L、反应时间130 min,镍和钴的平均浸出率分别为94.02%、94.64%。硫化钴镍渣中镍和钴的浸出符合收缩核模型,内扩散为反应的限制性环节,表观活化能分别为3.65、6.02 kJ/mol。可以通过减低渣粒度和固液比、维持较高的浸出液浓度、转速和氧分压来提高硫化镍钴渣的浸出速率。     

从高冰镍浸出渣中浸出铜

高冰镍浸出系统产出的高冰镍浸出渣中铜含量较高,研究了采用微波辅助加热、Fe_2(SO_4)_3氧化浸出工艺从渣中浸出铜,考察了微波功率、硫酸质量浓度、Fe_2(SO_4)_3用量、浸出时间、液固体积质量比对铜浸出率的影响。利用JMP软件分析试验结果,确定了Fe_2(SO_4)_3用量、硫酸质量浓度是影响铜浸出的显著因素,适宜的浸出条件为微波功率700 W,Fe_2(SO_4)_3质量浓度100g/L,硫酸质量浓度184g/L,液固体积质量比8∶1,浸出时间120min。在适宜条件下,铜浸出率为89.82%。     

碘—氨浸出体系用于废旧印刷线路板中金的浸取

为降低碘化法浸金的成本，提高浸出率，使用氨作为辅助络合剂，通过正交试验考察固液比、I₂/I^-摩尔比、KI浓度和氨水用量等影响浸出率的几个因素。研究结果表明：固液比对金的浸出效果影响最大，其后依次是氨水用量、KI浓度和I₂/I^-摩尔比。通过单因素试验获取各影响因素的最佳条件，结果表明：固液比的增加可提高金浸出率，当pH值在8～9之间，I₂/KI摩尔比为1∶8，KI质量浓度为0.25 g/mL，氨水体积浓度为1%，浸出时间为4 h时，混合体系对金的浸出效果最好，浸出率最高可达96%。氨水的添加对金的浸出有明显的促进作用，可提高金浸出率，降低碘化法浸金成本。     

湿法炼锌浸出渣与锌精矿联合浸出工艺研究

开展湿法炼锌浸出渣和锌精矿联合酸浸试验,利用硫酸浸出湿法炼锌常规浸出渣中以铁酸锌等方式存在的锌,同时采用高铁锌精矿将浸出液中的三价铁离子还原为二价铁离子,实现锌精矿中锌的同步浸出。探讨锌浸出渣和锌精矿投料比、初始硫酸浓度、反应时间、液固体积质量比和浸出温度对锌及伴生金属铜、铟和杂质金属铁浸出率的影响。结果表明,在浸出终点浸出液中硫酸浓度20～40g/L、锌浸出渣与锌精矿质量比1∶0.25、原料粒度-0.074mm、液固体积质量比6mL/g、反应温度90℃、反应时间3h的条件下,锌、铟、铜的浸出率都在96%以上,浸出液中95%以上的铁被还原为二价铁离子,满足后续工艺的要求。