富硼渣的碱解反应及活性评价方法的研究

研究了富硼渣与ＮａＯＨ溶液反应时时，液固比、ＮａＯＨ溶液及反应时间对碱解率的影响规律；考察了一定条件下碱解率与碳解率的对应关系；确定了评价富硼渣活性的适宜碱解反应条件。     

碳碱法加工硼铁矿的反应过程研究

分别以NaHCO3和CO2+ Na2 CO3为分解剂,研究了硼铁矿碳解反应过程.以NaHCO3为分解剂时,随着NaHCO3用量的增加,碳解率增大,当加入量为40 gNaHCO3/100 g矿时,碳解率可达78%.以CO2+ Na2 CO3为分解剂时,考察了各种因素对碳解反应的影响,液固比和添加二乙醇胺对碳解反应影响较小...     

低品位硼铁矿中提取硼酸

采用低温结晶法提取硼铁矿酸浸液中的硼酸,一次回收率为74.66%,并对其进行了XRD和SEM表征。分析其纯度为99.70%,达到了国家化工行业工业硼酸标准GB/T 538—2006中一等品的要求(硼酸质量含量在99.4%～100.8%之间)。最后分别测定了提取的硼酸中的杂质镁、铁和硫酸根的含量：采用火焰原子吸收光谱法测定了硼酸中杂质镁的含量,结果为硼酸中含镁1.34×10^-4;采用分光光度法测定了硼酸中杂质铁的含量,结果为硼酸中含铁8.175×10^-5;采用分光光度法测定了硼酸中杂质硫酸根的含量,结果为硼酸中含硫酸根1.116×10^-5。     

硼铁矿的开发利用

介绍了我国硼资源的总体情况。讨论了为了解决硼镁矿匮泛,开发利用硼铁资源的重要性,同时,介绍了硼铁矿开发利用的原则和工艺。     

碱提取法从虎杖中分离白藜芦醇的研究

对虎杖中的白藜芦醇采用碱性水溶液提取、调节溶液pH沉降的方法加以分离。考察了原料粒度、碱的种类、用量、酸的用量等因素对白藜芦醇提取的影响，确立了白藜芦醇碱提酸沉的最佳提取条件：提取溶剂用氢氧化钠调节pH值为10，恒速、均匀搅拌下，加热煮沸1h，滤液用1mol／L的盐酸调pH值为3，放置沉淀，真空过滤或离心分离。结果表明碱提酸沉分离方法优于传统的有机溶剂提取法。     

低品位硼铁矿中硼镁铁的共提取

采用硫酸浸出硼铁矿,通过乙醇结晶的方法从酸浸液中提取硫酸镁和硫酸亚铁,再利用低温结晶法提取硼酸,实现了低品位硼铁矿中硼镁铁的共提取。从理论上验证了采用乙醇结晶方法提取硼铁矿酸浸液中硫酸镁和硫酸亚铁的可行性,考察了溶液pH值、乙醇加入量和结晶温度对硫酸镁和硫酸亚铁在水-乙醇相中结晶析出的影响。结果表明,当溶液的pH值为2.0左右,乙醇加入体积为溶液体积的1.5倍,结晶温度为室温时,硫酸镁和硫酸亚铁有较高的结晶析出率,分别达到97.73%和97.86%,其纯度分别为99.10%和98.48%。采用低温结晶法提取硼酸的一次收率为74.66%,硼酸纯度达到99.70%,主要杂质镁和铁的含量分别为1.34×10-3%和8.54×10-3%。这种共提取方法操作条件相对温和,能耗较低,提取率高,并且所用的乙醇还可以蒸馏回收。     

硼铁矿高炉铁硼分离工艺试验研究

辽宁东部山区储有丰富的硼铁矿资源，由于矿物结构复杂，通过选矿只能得到含硼铁精矿和硼精矿。采用高炉法处理含硼铁精矿可使铁硼有效分离得到含硼生铁和富硼渣。硼精矿和富硼渣可代替面临枯竭的硼镁石作生产硼砂和硼酸的原料。     

硼铁矿闪速焙烧新工艺研究

以硼铁矿为原料生产硼酸盐产品,通常是先选出铁精矿后,含硼尾矿再加工成粉状硼精矿.而碱法加工硼矿石时,必须对硼矿石进行焙烧,以提高三氧化二硼的活性.针对硼铁矿活化焙烧过程中焙烧工艺条件难控制、熟矿粉活性差的问题,提出了将预干燥和活化焙烧有机结合的低品位硼铁矿闪速焙烧新工艺.在实验室试验及工业化生产的基础上,对此工艺进行了综合评价,对不足之处提出对应改进方案.此工艺高效可行,在一定品位下可将硼铁矿的活化率提高到85%～90%.     

翁泉沟硼铁矿的综合利用

提出了翁泉沟硼铁矿的综合利用流程:即矿石先经选矿而得硼精矿和硼铁混合精矿;硼精矿用碳碱法加工而得硼砂;硼铁混合精矿用硫酸溶解其中的硼镁石,在阻溶剂的作用下,磁铁矿溶解很少,酸解后进行固液分离,固相即为铁精矿,送去炼铁,酸解液除铁后,加入盐析剂氯化镁,在高温下蒸发析出硫酸镁,过滤后母液冷却至常温又析出硼酸,硼酸母液循环回到蒸发器,从而高回收率得到硫酸镁和硼酸。     

电炉富硼渣活性的碱解评价方法研究

介绍了电炉富硼渣活性的碱解评价方法,对液固比、碱液质量分数及反应时间等实验条件进行了研究．确定了最佳实验条件,结果表明：该方法实验耗时短且在常压下进行．重现性良好．可应用于工业生产。     

MnO2掺杂对[(Pb,Ca)La](Fe,Nb)O3介质陶瓷结构及微波性能的影响

摘要:研究了MnO2 掺杂量对[(Pb0.5Ca0.5)0.92La0.08](Fe0.5Nb0.5)O3 陶瓷结构及介电性能的影响。研究表明MnO2 是良 好的烧结助剂，可降低体系的烧结温度60 ～1 0 0℃，同时提高陶瓷体密度。X R D 图谱证明当M n O2 的质量分数≤ 2% 时，陶瓷为钙钛矿相及焦绿石相，表明M n 4 进入主相晶格。随M n O2 的增加体系介电常数先增加后减小，同 时造成品质因数及谐振频率温度系数的单调下降。     

Polymerization of epoxides catalyzed by a mixed‐valent iron trifluoroacetate [Fe3O(O2CCF3)6(H2O)3]

The readily available mixed‐valent iron trifluoroacetate complex [Fe₂^IIIFe^II(µ₃‐O)(O₂CCF₃)₆(H₂O)₃] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end‐group analysis by ¹⁹F NMR spectroscopy, a Lewis acid (LA^⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry     

Determination of 1:2 Ordered Domain Boundaries in Ba[(Co,Zn, Mg)1/3Nb2/3]O3 Dielectric Ceramics

The boundaries of 1:2 ordered domains in Ba[(Co, Zn, Mg)_1/3Nb_2/3]O₃ perovskite ceramics are comprehensively studied by high‐resolution transmission electron microscopy (HRTEM) on the base of atomic position simulation. The atomic configurations for four types of twin boundaries are determined. A‐type and B‐type boundary, which lie along (001)_c and (110)_c planes, respectively, are conservative. C‐type boundary parallels to (111)_c plane, while Г‐type boundary is perpendicular to (111)_c plane. At C‐type and Г‐type boundary, atomic intersection leads to a buffer layer, among which the B‐site cations are generally disordered. The width of Г‐type boundary is larger than that of C‐type boundary, so is the perturbation to the system. The energy of four types of twin boundaries is proved to be “A‐type & B‐type < C‐type < Г‐type” according to the magnitude of the destabilization to the system. Single antiphase boundary (APB) is considered to be nonconservative. However, when combined with conservative twin boundary, an extra ordered structure with a periodicity of 1.24 nm along [001]_c direction and a periodicity of 0.87 nm along [110]_c direction forms. The boundary regions are indeed stabilized by the new superlattice.     

P2O4萃取硫酸铝溶液中Fe^3＋离子的研究

选取P2O4为萃取剂,采用煤油作为稀释剂,考察了单级萃取硫酸铝溶液中铁离子的各影响因素,并在此基础上进行了二级逆流萃取的实验研究.结果表明:温度为80℃、萃取剂浓度50%、萃取时间90 min,铁的萃取率可达97.50%;经过二级逆流萃取后的硫酸铝溶液制备出的产品为低铁级硫酸铝产品.     

[(2Y-ZrO2)-Al2O3]纳米微粉制备的研究

本研究采用SoL-GeL法和自动引燃法制备[(2Y-ZrO)-AlO]超微粉,并进行了微观结构分析。为比对223两种超微粉性能的差异,采用注浆成型法制备样品,并分别测定抗折强度,断裂韧性和烧结温度。结果表明:自动引燃制备的ZrO-AlO掺稀土纳米微粉,工艺简单、细小均匀,由其烧造的样品较SoL-GeL法样品抗弯强度高,223断裂韧性好,烧结温度低。     

The synthesis and microwave dielectric properties of Mg3B2O6 and Mg2B2O5 ceramics

Single-phase Mg₃B₂O₆ and Mg₂B₂O₅ ceramics were synthesized and then structurally and dielectrically characterized. The highest Qxf value of 230,900 GHz was obtained for a Mg₃B₂O₆ ceramic with a density of 97% and 1000-μm grains. Considerably lower Qxf values (10,000–32,000 GHz) were determined for the Mg₂B₂O₅ ceramic. Mg₃B₂O₆ and Mg₂B₂O₅ exhibited permittivities (?) of 7.2 and 6.2–7.0, respectively. Both ceramics showed negative temperature coefficients of resonant frequency (τ_f) of ?18 to ?45 ppm/°C.     

Microwave properties of Ba(Mg1/3Ta2/3)O3, Ba(Mg1/3Nb2/3)O3 and Ba(Co1/3Nb2/3)O3 ceramics revealed by Raman scattering

Five Ba(Co_1/3Nb_2/3)O₃ samples sintered at different temperatures (form 1350 to 1550 °C), one Ba(Mg_1/3Ta_2/3)O₃ and a Ba(Mg_1/3Nb_2/3)O₃ sample were examined by Raman scattering to reveal the correlation of the 1:2 ordered perovskite structure with the microwave properties, such as dielectric constant and Q factors. The Ba(Co_1/3Nb_2/3)O₃ sample sintered at 1400 °C, which possesses the highest microwave Q value and the lowest dielectric constant among five Ba(Co_1/3Nb_2/3)O₃ samples, has the narrowest width and the highest frequency of the stretch mode of oxygen octahedron (i.e. A_1g(O) near 800 cm⁻¹). We found that the dielectric constant is strongly correlated with the Raman shift of A_1g(O) stretch modes, and the width of A_1g(O) stretch mode reflects the quality factor Q × f value in the 1:2 ordered perovskite materials. This concludes that the oxygen octahedron play an important role of the material's microwave performance. Based on the results of Q × f values and the lineshapes of A_1g(O) stretch mode, we found that the propagation of microwave energy in Ba(Mg_1/3Ta_2/3)O₃ and Ba(Mg_1/3Nb_2/3)O₃ shows weak damping behavior, however, Ba(Co_1/3Nb_2/3)O₃ samples sintered at different temperature exhibit heavily damped behavior.     

New magnetic-fluorescent bifuntional (Y0.9Ln0.1VO4/Fe3O4)@SiO2 and [(Y0.9Ln0.1VO4@SiO2)/Fe3O4@SiO2] materials

The preparation and study of new bifunctional (Y_0.9Ln_0.1VO₄/Fe₃O₄)@SiO₂ and [(Y_0.9Ln_0.1VO₄@SiO₂)/Fe₃O₄@SiO₂] samples with Ln = Nd or Tb is described in detail. The influence of Fe₃O₄ content and silica coating on Y_0.9Ln_0.1VO₄@SiO₂ samples is analyzed to decide on their potential utility. Materials of this type are currently of great interest in the biomedicine field based on their potential use as bifunctional materials. On the one hand, because they can be directed using an external magnetic field and, on the other, because they can allow the visualization of diseased cells after appropriate functionalization. Y_0.9Ln_0.1VO₄ samples with Ln = Nd or Tb were prepared by a hydrothermal process, while Fe₃O₄ sample was prepared by the coprecipitation method. These samples and different mixtures of them were treated with tetraethyl orthosilicate (TEOS) to proceed with their silica coating. All diffraction maxima of Y_0.9Ln_0.1VO₄ samples were indexed on a tetragonal symmetry of space group I4₁/amd, compatible with a zircon structure-type. In the case of Fe₃O₄ sample, all reflections were indexed to a cubic symmetry of space group Fd $\stackrel{￣}{3}$ m, characteristic of an inverse spinel structure-type. These results also agreed well with the FTIR spectra of the investigated samples. For the first time, the experimental FTIR study of Y_0.9Ln_0.1VO₄ samples was complemented with a theoretical vibrational study based on the YVO₄ structure. To carry out this theoretical study, different density functional theory (DFT) methods and different basis sets were used. Silica presence in samples was clearly verified in both, the XRD profiles and the FTIR spectra. Elongated and spherical particles are found in TEM images of these samples. The study of PL emission and magnetic behavior showed that [(Y_0.9Ln_0.1VO₄@SiO₂)/Fe₃O₄@SiO₂] samples are the most suitable for use as bifunctional materials.     

等轴晶ZrO2(Al2O3, Fe2O3)复相陶瓷的制备

讨论了以硝酸盐溶液为原料，经喷雾干燥、热解、成型、烧结或直接烧结制备等轴晶ZrO2(Al2O3, Fe2O3)复相陶瓷的过程. 研究了成型压力、烧结温度、恒温时间及Al3+, Fe3+的加入对ZrO2陶瓷的相组成、晶粒大小和形貌的影响. 结果表明：成型压力对相组成及晶粒尺寸无明显影响；无论是直接采用硝酸盐复合粉末还是采用氧化物粉末压坯作为前驱物，烧结产物的形貌、相组成不变；加入Fe2O3可克服微观结构层状堆垛，获得相对细小均匀的等轴晶粒，且随Fe2O3含量的增加，单位体积中a-(Al, Fe)2O3核心的数量增加，晶粒尺寸更加细小、均匀，Fe2O3含量相对于Al2O3在20%左右时效果最佳；各相晶粒在长时间高温烧结时生长速度较为缓慢，0.5 h为0.5 mm左右，烧结12 h才到2.0 mm左右.     

Crystal structure and microwave dielectric properties of NaPb2B2V3O12(B=Mg,Zn) ceramics

Two low temperature sintered NaPb₂B₂V₃O₁₂ (B?=?Mg, Zn) ceramics with garnet structure were synthesized through conventional solid state reaction route and their crystal structure and microwave dielectric properties were investigated for the first time. Rietveld refinements of XRD patterns show both the compounds belong to cubic symmetry with space group Ia-3d. Observed number of Raman bands and group theoretical predictions also confirm cubic symmetry with space group Ia-3d for both NPMVO and NPZVO. At the optimum sintering temperature of 725?°C NPMVO has a relative permittivity of 20.6?±?0.2, unloaded quality factor (Q_uxf) of 22,800?±?1500?GHz (f?=?7.7?GHz) and temperature coefficient of resonant frequency +25.1?±?1?ppm/°C while NPZVO has relative permittivity of 22.4?±?0.2, Q_uxf of 7900?±?1500?GHz (f?=?7.4?GHz) and near zero temperature coefficient of resonant frequency of -6?±?1?ppm/°C at 650?°C. The relative permittivity of the compounds is inversely related to the corresponding Raman shifts.