四氟化硅逸出法测定氟石中氟化钙

氟石主要成分为氟化钙、常含有二氧化硅、碳酸钙、铁、铅、锌、钡盐等杂质.一般采用EDTA容量法(GB5195—85)测定氟石中氟化钙量.但此法不适用于含锶的氟石中氟化钙量的测定;如氟石中含有可溶性硅酸钙,亦不适用;铅锌如不掩蔽,也使测定结果偏高.     

Synthesis and Characterization of Fluoro- and Chloro- bimetallic Alkoxides as Precursors for Luminescent Metal Oxide Materials via Sol-Gel Technique

Heterobimetallic alkoxides are broadly recognized as versatile precursors for luminescence materials, and efforts are being made to develop novel routes by applying the concept of geometrical molecular design, for their synthesis and to design a single source precursor suited to photoluminescent materials. Novel and new series of bimetallic alkoxides has been prepared by metathesis route. They exhibit a lower sensitivity towards hydrolysis and so they are easier to handle as compared to other alkoxides. All the compounds were characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopies. FT-IR revealed that the molecular structure of these metal alkoxides was retained to a large extent in 4 ： 1 halogenated alcohol-benzene solution. The heteronuclear NMR spectroscopy provided useful information about chemical shifts for better understanding the likely structure based on interactions with their coordinate metals. The mass spectra show similar types of fragmentation pattern. SEM-EDS analyses showed consistency with the formulation. XRD patterns show an enhanced homogeneity at high temperature. TGA measurements show that thermal decomposition occured in steps that depended entirely on the chemical compositions and the synthesis routes. SEM observation reveals that the morphology and particle size strongly depend on synthesis routes for their precursors.     

X射线荧光光谱法测定氟石中的氟化钙和杂质的含量

本文采用Ｌi２Ｂ４Ｏ７：ＬiＢＯ２＝１２：２２作熔剂制备氟石熔融片,用波长色散Ｘ射线荧光光谱仪测定氟石中的ＣaＦ２、ＳiＯ２、Ｆe２Ｏ３、ＳＯ３、Ｐ２Ｏ５。本法测量 准确度、精密度较好,所得结果与湿法化学分析结果一致。     

ICP-AES法测定萤石中的主次成分

萤石通过醋酸加热使ＣaＣＯ３溶解,再经过滤、沉淀、烘干,以碳酸钠、硼砂混合熔剂熔 融,酸学好以后,采用ＩＣＰ－ＡＥＳ法测定碳酸钙、氟化钙及二氧化硅、三氧化铁。此方法精密度好,回收率在９６．０％－１０１．４％之间。     

石杉碱甲类拟物的合成及药理研究1: (±)-14-氟石杉碱甲

用两种方法合成了(±)-14-氟石杉碱甲(6),并测定了其抑制乙酰胆碱酯酶的生物活性。其抑制活性是(-)-石杉碱甲(1)的1/62。     

新型混价稀土氟化物KEu(Ⅱ)Ce(Ⅲ)F6

用碱金属热还原法合成了含有混价稀土的新型氟化物KEuCeF6,用组成分析、X射线衍射、光电子能谱和荧光光谱对新化合物的组成、结构和稀土离子的氧化态进行了表征。KEuCeF6的晶体属gagarinite(钠钙钇氟石)和UCl3结构的相关型。空间群P3 ,a=645.4(2)pm,c=373.0(1)pm,c/α=0.578,Z=1;其中的铕和铈的氧化态分别为+2和+3.     

AAS法测定出口氟石粉中锰的研究

基于出口矿产品氟石粉需要测定锰而建立该方法.该方法是将氟石样品经过氢氟酸去除硅,高氯酸冒烟,冷却后再用盐酸、硼酸加热溶解等处理过程,标准溶液中需加入与样品相匹配的钙基体进行测定.锰的线性范围为0.09～2.5μg·mL-1,测量下限为0.001%.用不同含量水平的实际样品所测定的结果与用ISO高碘酸钠光度法测定的结果一致.该方法的特点是准确可靠、简便可行、易于推广.     

硅沸石—2在合成气制低碳烯烃中的催化作用

在n-C_4H_11N-Na_2O-SiO_2-H_2O体系中,首次用正丁胺为模板剂合成了silicalite-2(硅沸石-2)。Silicalite-2在合成气制烯烃反应中作为活性组份载体对产物C_—C_4烯烃具有较高的选择性;改变合成条件可使silicalite-2X射线衍射图谱中2θ=8.7°,23.0°两峰的峰强比发生规律性变化,而峰强比值的改变将引起催化性能变化。负载铁、钾的silicalite-2催化剂用于一氧化碳加氢合成低碳烯烃反应,在反应温度250℃、空速200h~(?)、CO/H_2摩尔比为1的条件下,产物中C_2—C_4烯烃选择性可达65%。     

氢化物连续发生等离子体原子发射光谱法测定氟石中痕量砷

将氢化物连续发生等离子体原子发射光谱(CF HG ICP AES)联用技术应用于氟石中痕量砷的测定,对方法的工作参数进行了试验,方法的线性范围为0.005 0~0.100 0 mg·L-1,检出限为0.8 g·L-1,回收率为95%,RSD为5.0%。