CaO和NaCl焙烧混合稀土精矿过程中的分解反应

用XRD和TG-DTA热分析技术, 研究了含独居石和氟碳铈镧矿的混合稀土精矿在100～1000 ℃焙烧过程中, 添加CaO, NaCl时, REPO4和REFCO3的分解反应. 研究结果表明: 不添加CaO和NaCl时, 仅在377～450 ℃范围内存在REFCO3的分解反应, 其产物是REOF, RE2O3, 以及Ce2O3进一步的氧化产物CeO2, 而REPO4不分解; 添加CaO后在660～750 ℃之间, CaO有3种分解作用: (1) CaO分解REPO4, 其产物是RE2O3和Ca3(PO4)2. (2) CaO分解REOF, 其产物是RE2O3和CaF2. (3) CaO和REOF的分解产物CaF2共同作用分解REPO4, 其分解产物为RE2O3, Ca5F(PO4)3; 添加CaO, NaCl后, 混合精矿的分解率明显提高, NaCl的作用是为反应体系提供了液相, 促进了固相反应物间的传质过程, 加快了反应速度. 与此同时NaCl还可能参加了CaO分解REPO4的反应.     

对硅酸聚合机制反应级数的验证

用胶凝法研究酸化了的不同摩尔比 (Si O2 /Na2 O)的硅酸钠溶液的胶凝速度 ,发现在恒盐条件下 ,硅酸胶凝速度常数是 2 ,这个结果和我们过去所提出的硅酸聚合机制符合一致。     

Formation at low surfactant concentrations and characterization of mesoporous MCM-41

At low concentrations of cetyltrimethylammonium bromide,all silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between self-assembled surfactant molecule aggregates and aniomc silicate polymers.The resulting materials are characterized by XRD,FT-IR,solid state 29Si MAS NMR,thermal analysis and N2 adsorption-desorption measurements.After soluble ions are removed,the interactors between surfactant micelles and silicate polymers are reorganized and then form mesostructures 1 he hexagonal framework is sonsistent with amorphous silica gel.The structures of materials depend on the synthesis conditions Hydrothermal process improves the interactions between molecules and increases the degree of framework silicon atom polymerization The.surface area and the mesopore volume of the material prepared at 100℃ increase by 87% and 71 %,respectively,compared with those obtained at room temperature.     

介孔分子筛MSU-1的合成

MSU X介孔分子筛具有三维立体交叉排列的蠕虫状孔道结构,有利于客体分子在其孔道内扩散[1]。目前合成MSU X的原料[2 4]TEOS水解速度慢,合成过程较易控制,但价高、易燃、有刺激性。本文采用文献[5 7]法,以水玻璃、A(EO)9为原料,在酸性至近中性的范围里合成了MSU 1介孔分子筛,与TEOS为原料的MSU 1合成进行了比较,考察了pH值和不同类型表面活性剂(脂肪醇聚氧乙烯醚和烷基酚聚氧乙烯醚)对产物结构性质的影响。1　实验部分1 1　试剂和仪器水玻璃(SiO2%≈26、Na2O%≈8),工业级,青岛海洋化工厂生产;脂肪醇聚氧乙烯醚非离子表面活性…     

无机添加剂对硝酸铵拒爆性的影响研究

考察了无机添加剂对农用硝酸铵拒爆性的影响。结果表明，当硝酸铵中添加3%的无机改性剂GXJ 1和10%的无机改性剂GXJ 2后，其拒爆性能明显增强；改性后的硝酸铵按照工业炸药配方配制成铵油炸药，不能被8号雷管起爆。而且改性后的硝酸铵颗粒强度高，不易粉化、结块和吸潮，具有优良的肥料品质。经济效益分析也表明，改性硝酸铵具有广阔的市场应用前景。通过X射线衍射分析、扫描电子显微镜分析等对改性硝酸铵进行了表征，并对拒爆机理进行了初步探讨。     

硝酸钐水合物热分解过程的研究

Sm(NO_3)_3·6H_2O热分解过程的研究工作虽有文献报道,但结果不尽相同。文献[2]不同于文献[1,3],认为分解过程中存在无水盐阶段;文献[3]不同于文献[1,2],认为分解过程中存在低水合物。而且文献尚缺低水合物热分解机理的报道。我们也曾做过一些工作,但脱水阶段也不详尽。为此,我们详细地研究了Sm(NO_3)_3·nH_2O(n=     

Electrical conductivity measurements of aqueous sodium chloride solutions to 600°C and 300 MPa

Electrical conductance measurements of dilute (<0.1>^–1) aqueous NaCl solutions were made primarily to quantify the degree of ion association which increases with increasing temperature and decreasing solvent density. These measurements were carried out at temperatures from 100 to 600°C and pressures up to 300 MPa with a modified version of the apparatus used previously in the high temperature study in this laboratory. Particular emphasis was placed on conditions close to the critical temperaturelpressure region of water, i.e., at 5° intervals from 370 to 400°C. The results verify previous findings that the limiting equivalent conductance A_o of NaCl increases linearly with decreasing density from 0.75 to 0.3 g-cm^–1 and also with increasing temperature from 100 to 350°C. Above 350°C. A_o is virtually temperature independent. The logarithm of the molal association constant as calculated exclusively from the data400°C is represented as a function of temperature (Kelvin) and the logarithm of the density of water (g-cm^–3) as follows:

过硼酸钠对于有机物的氧化作用的研究 II: 氧化偶氮硝基苯类的合成

作者曾报道过硼酸钠在醋酸溶液中可使芳氨基氧化成硝基;McKillop等曾报道将过硼酸钠用于官能团的氧化;Huestis曾报道在冰醋酸溶液中用过硼酸钠将芳胺氧化成偶氮苯。这些都表明过硼酸钠是一种优良的氧化剂,反应条件温和、选择性强、氧化剂本身。价廉且其还原后所生成的硼酸钠易于处理和排放。因此,值得深入研究其应用范围。我们在此则报道一组以过硼酸钠为氧化剂,使芳胺氧化成氧化偶氮苯的条件。最近我们发现,在乙醇-磷酸体系中,过硼酸钠能顺     

过碳酸钠-醋酸酐作用下的Baeyer-Villiger反应

在醋酸酐介质中, 过碳酸钠可以与酮进行Baeyer-Villiger反应, 将它们氧化成相应的酯。其中脂环酮的反应结果较好, 环内酯的产率约为80%。芳香酮除芳环被活化的以外, 效果欠佳。当反应施加超声辐射后可显著加快反应速度, 并对过碳酸钠的作用机理进行了讨论。     

Spreading of dipalmitoyl phosphatidylcholine on the surface of sodium deoxycholate aqueous solution

The surface pressure vs. mokcular surface area relations for dipalmitoyl phosphatidylcholine (DPPC) insoluble monolayer and sodium deoxycholate (SDC) adsorbed monolayer,L and D1, respectively, were obtained from the analyses of surface tensions measured by the Wilhelmy glass plate. Also, D1 was obtained by a drop-weight method. Next, the surface pressure time course,(t), of the SDC aq. was measured by the Wilhelmy plate before and after DPPC was spread on the liquid surface. At DPPC spreading,(t) jumped to a maximum,, and decreased along an exponential curve. The values of with various surface amounts of DPPC and bulk concentrations of SDC were analyzed using a dual surface-region model. The model enabled the estimation of. For better fitting, modified relations were constructed in place of D1. The exponential decrease of(t) was also observed on the SDC adsorbed monolayer which was rapidly compressed by a moving barrier. The(t) relaxation rate constants of the SDC monolayers which were compressed by DPPC spreading and the moving barrier agreed with each other, suggesting a desorption of SDC from the surface.